JP7382392B2 - Projection display components, windshield glass, and head-up display systems - Google Patents

Description

The present invention relates to a projected image display member used in a head-up display system, a windshield glass using the projected image display member, and a head-up display system.

Currently, there is a system called a head-up display or head-up display system that projects an image onto the windshield of a vehicle and provides the driver with various information such as a map, driving speed, and vehicle status. ing.
In a head-up display system, a virtual image of an image that is projected on a windshield and includes the various information described above is observed by a driver or the like. The imaging position of the virtual image is located on the front side outside the vehicle from the windshield, and the imaging position of the virtual image is usually 1000 mm or more forward of the windshield and located on the outside side of the windshield. This allows the driver to obtain the above-mentioned various information while looking at the outside world in front of him without having to move his line of sight. Therefore, when using a head-up display system, the driver can obtain various information while also obtaining more information. You are expected to drive safely.
Windshield glass can constitute a head-up display system by forming a projection display section using a half mirror film. Various types of half mirror films have been proposed.

Patent Document 1 describes a light reflective layer PRL-1 having a center reflection wavelength of 400 nm or more and less than 500 nm and a reflectance of 5% or more and 25% or less for normal light at the center reflection wavelength, and a light reflection layer PRL-1 having a center reflection wavelength of 500 nm or more and less than 600 nm. A light reflective layer PRL-2 having a wavelength and a reflectance for normal light at a central reflection wavelength of 5% or more and 25% or less, and a reflectance for normal light at a central reflection wavelength that has a central reflection wavelength of 600 nm or more and less than 700 nm. is 5% or more and 25% or less, at least two or more light-reflecting layers containing one or more light-reflecting layers and having mutually different center reflection wavelengths are laminated and laminated. It is described that at least two or more light-reflecting layers are light-reflecting films that reflect polarized light in the same direction.

Patent Document 2 describes a light reflecting layer PRL-1 having a center reflection wavelength of 400 nm or more and less than 500 nm in planar shape and a reflectance of 5% or more and 25% or less for normal light at the center reflection wavelength, and a light reflecting layer PRL-1 with a planar shape of 500 nm or more and less than 500 nm. A light reflecting layer PRL-2 having a center reflection wavelength of 600 nm or more and less than 700 nm and a reflectance of 5% or more and 25% or less for normal light at the center reflection wavelength, and a light reflection layer PRL-2 having a center reflection wavelength of 600 nm or more and less than 700 nm in planar shape and having a center reflection wavelength of 600 nm or more and less than 700 nm. Among the light reflective layers PRL-3, which have a reflectance for normal light at a reflection wavelength of 5% or more and 25% or less, at least two light reflective layers that include one or more light reflective layers and have mutually different center reflection wavelengths The light-reflecting layers are laminated, and at least two or more light-reflecting layers to be laminated have the property of reflecting polarized light in the same direction, and each maintains a curved shape in an unloaded state, and A curved light-reflecting film having a thickness of 50 μm or more and 500 μm or less is described.
In both of Patent Documents 1 and 2 mentioned above, each light reflection layer has a high reflectance for light emitted from an image display means that has been converted into a specific polarized light, and is used for a head-up display. be able to.

Patent Document 3 discloses that when natural light including S-polarized light as well as P-polarized light is used as projection light by a combination of a windshield glass made of a wedge-shaped laminated glass that can reduce double images and a light reflection layer made of a cholesteric liquid crystal layer. describes that the brightness of projected light is significantly improved.

International Publication No. 2016/056617 Japanese Patent Application Publication No. 2017-187685 International Publication No. 2016/133187

The light reflective films described in Patent Document 1 and Patent Document 2 mentioned above are used in head-up display systems. In addition to having high visible light transmittance, head-up display systems are required to be able to view images even when the driver is wearing polarized sunglasses. Furthermore, the reality is that the projected light from a projector used in a head-up display system often contains a large amount of S-polarized light or natural light.
However, polarized sunglasses worn while driving generally block S-polarized light to reduce glare and the like caused by reflected light from the hood that is visible to the driver.
That is, with respect to projected light including such S-polarized light, the light reflecting films described in Patent Document 1 and Patent Document 2 reflect weak P-polarized light, resulting in poor image visibility when wearing polarized sunglasses. Further, in the configuration of Patent Document 3, projection light including natural light is assumed, but image visibility is insufficient when wearing polarized sunglasses in a bright environment such as during the day.
An object of the present invention is to provide a projection image display member, a windshield glass, and a windshield glass, which have high visible light transmittance even when the projected light of a projector includes S-polarized light or circularly polarized light, and which have excellent brightness of displayed images suitable for polarized sunglasses. Our objective is to provide a head-up display system.

[1] A projected image display member that is provided on glass or resin to constitute a projected image display section on glass or resin,
It has at least a retardation layer containing a rod-like liquid crystal compound,
The retardation layer is a projection image display member characterized in that a rod-shaped liquid crystal compound is oriented obliquely with respect to the surface of the retardation layer.
[2] The average tilt angle of the rod-like liquid crystal compound in the retardation layer is 10 to 80 degrees with respect to the surface of the retardation layer,
The retardation layer has a front retardation of 100 to 500 nm at an inclination angle of 0 degrees, which is a retardation measured by entering light from a direction perpendicular to the direction of the average inclination angle with respect to the surface of the retardation layer. The projection image display member according to [1].
[3] The projection image display member according to [1] or [2], which includes a selective reflection layer.
[4] The projection image display member according to [3], wherein the selective reflection layer is a reflection layer that reflects linearly polarized light.
[5] The projection image display member according to [3], wherein the selective reflection layer is a circularly polarized light reflective layer.
[6] The projection image display member according to [3], wherein the selective reflection layer is a non-polarized reflection layer.
[7] The projection image display member according to any one of [1] to [6], which includes a polarization conversion layer.
[8] The polarization conversion layer is a layer in which a helical alignment structure of a liquid crystal compound is fixed,
The projection image display member according to [7], wherein in the polarization conversion layer, the film thickness and the pitch number of the helically oriented structure satisfy the following relational expressions (i) and (ii).
When the pitch number of the polarization conversion layer is x and the film thickness is y (unit: μm) (i) 0.1≦x≦2.0
(ii) 0.5≦y≦7.0
[9] The projection image display member according to [7], wherein the polarization conversion layer is a retardation layer and has a front retardation of 100 to 500 nm.
[10] A projected image display member that is provided on glass or resin to constitute a projected image display section on glass or resin,
having at least one retardation layer,
A projection image display member characterized in that the front retardation of the retardation layer is 100 to 350 nm.
[11] The projection image display member according to [10], which includes a selective reflection layer.
[12] The projection image display member according to [11], wherein the selective reflection layer is a reflection layer that reflects linearly polarized light.
[13] When the upper part of the vertical direction when mounted on a vehicle is set to 0 degrees,
As described in [12], the direction of the refractive index anisotropy of the linearly polarized light reflective reflective layer is tilted clockwise at an angle of 10 to 80 degrees or 100 to 170 degrees when viewed from the projection image display side. Components for displaying projected images.
[14] The projection image display member according to [11], wherein the selective reflection layer is a circularly polarized light reflective layer.
[15] The projection image display member according to [11], wherein the selective reflection layer is a non-polarized reflection layer.
[16] The projection image display member according to any one of [10] to [15], comprising a polarization conversion layer.
[17] The polarization conversion layer is a layer in which a helical alignment structure of a liquid crystal compound is fixed,
The projection image display member according to [16], wherein in the polarization conversion layer, the film thickness and the pitch number of the helically oriented structure satisfy the following relational expressions (i) and (ii).
When the pitch number of the polarization conversion layer is x and the film thickness is y (unit: μm) (i) 0.1≦x≦2.0
(ii) 0.5≦y≦7.0
[18] The projection image display member according to [16], wherein the polarization conversion layer is a retardation layer and has a front retardation of 100 to 500 nm.
[19] A windshield glass comprising a windshield glass body and the projection image display member according to any one of [1] to [18].
[20] The windshield glass according to [19], wherein the windshield glass body is a laminated glass.
[21] The windshield glass according to [20], wherein the windshield glass body is wedge-shaped glass.
[22] The windshield glass according to any one of [19] to [21], wherein a projection image display member is attached to the inner surface of the windshield glass body.
[23] The windshield glass according to [20] or [21], wherein a projected image display member is sandwiched between the windshield glass body.
[24] The projected image display according to any one of [1] to [18], which is provided on a wedge-shaped glass serving as windshield glass, a projector that projects an image onto the wedge-shaped glass, and an image projection surface from the wedge-shaped glass projector. A head-up display system having a member for use.
[25] The head-up display system according to [24], wherein the projector mainly emits S-polarized light.
[26] The head-up display system according to [24], wherein the projector mainly emits circularly polarized light.

The present invention provides a windshield glass and a combiner having a projection image display member.
It is preferable that a projection image display member is disposed between the first glass plate and the second glass plate of the windshield glass. Alternatively, the projected image display member may be arranged on the projection light incident side (concave side) of the windshield glass.
It is preferable that an intermediate film is provided between at least one of the first glass plate and the projected image display member and between the projected image display member and the second glass plate.
The windshield glass preferably has a wedge-shaped cross-section, and the wedge-shaped glass preferably has a wedge-shaped intermediate film between the first glass plate and the second glass plate. It is preferable to use the present invention as a head-up display system having a projector that irradiates a windshield glass with projection light including S-polarized light.

According to the present invention, a projected image display member and a windshield are capable of realizing high visible light transmittance and image visibility when wearing polarized sunglasses even when the projected light of a projector includes S-polarized light or circularly polarized light. Glass and head-up display systems can be provided.

FIG. 1 is a schematic diagram showing an example of a projection image display member according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the slow axis. FIG. 3 is a schematic diagram showing an example of a head-up display having a projection image display member according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing an example of a windshield glass having a projection image display member according to an embodiment of the present invention. FIG. 5 is a side view of the laminated glass in Example 1. FIG. 6 is a diagram of the laminated glass in Example 1 viewed from the first polarization conversion layer side. FIG. 7 is a diagram showing a measurement system for evaluating brightness. FIG. 8 is a diagram showing a measurement system for evaluating suitability for polarized sunglasses.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, a projection image display member, a windshield glass, and a head-up display system of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
Note that the figures described below are illustrative for explaining the present invention, and the present invention is not limited to the figures shown below.
In addition, in the following, "~" indicating a numerical range includes the numerical values written on both sides. For example, when ε ₁ is from the numerical value α ₁ to the numerical value β ₁ , the range of ε ₁ is the range including the numerical value α ₁ and the numerical value β ₁ , and expressed in mathematical symbols as α ₁ ≦ε ₁ ≦β ₁ .
Unless otherwise specified, angles such as "angle expressed in specific numerical values", "parallel", "perpendicular", and "perpendicular" include error ranges generally accepted in the relevant technical field.
Further, "same" includes the generally acceptable error range in the relevant technical field, and "overall" etc. also includes the generally acceptable error range in the relevant technical field.

"Selective" with respect to circularly polarized light means that the amount of either the right-handed circularly polarized component or the left-handed circularly polarized component of the light is greater than the other circularly polarized component. Specifically, when referring to "selective", the degree of circular polarization of light is preferably 0.3 or more, more preferably 0.6 or more, and even more preferably 0.8 or more. More preferably, it is substantially 1.0. Here, the degree of circular polarization is expressed as |I _R - I _L |/(I _R + I _L ), where the intensity of the right-handed circularly polarized component of light is I _R and the intensity of the left-handed circularly polarized component is I _L . is the value to be used.

When referring to circularly polarized light, "sense" means whether it is right-handed circularly polarized light or left-handed circularly polarized light. The sense of circularly polarized light is that when you look at the light as if it is traveling towards you, if the tip of the electric field vector rotates clockwise as time increases, it is right-handed circularly polarized light, and if it rotates counterclockwise, it is left-handed circularly polarized light. Defined as circularly polarized light.

The term "sense" is sometimes used to refer to the twist direction of the helix of cholesteric liquid crystal. When the helical twist direction (sense) of the cholesteric liquid crystal is right, it reflects right-handed circularly polarized light and transmits left-handed circularly polarized light, and when the sense is left, it reflects left-handed circularly polarized light and transmits right-handed circularly polarized light.

When we say "light," we mean visible light and natural (non-polarized) light, unless otherwise specified. Visible light is electromagnetic waves with wavelengths that can be seen by the human eye, and usually indicates light in the wavelength range of 380 to 780 nm. Invisible light is light in a wavelength range of less than 380 nm or in a wavelength range of more than 780 nm.
Although not limited to this, among visible light, light in the wavelength range of 420 to 490 nm is blue (B) light, and light in the wavelength range of 495 to 570 nm is green (G) light. , light in the wavelength range of 620 to 750 nm is red (R) light.

The "visible light transmittance" is the A light source visible light transmittance defined in JIS (Japanese Industrial Standards) R 3212:2015 (automotive safety glass testing method). That is, the transmittance of each wavelength in the wavelength range of 380 to 780 nm is measured using a spectrophotometer using A light source, and the transmittance is obtained from the wavelength distribution and wavelength interval of the CIE (Commission Internationale de l'Eclairage) photopic standard luminous efficiency. This is the transmittance obtained by multiplying the transmittance at each wavelength by the weighted coefficient given by the transmittance and taking a weighted average.
When simply referring to "reflected light" or "transmitted light", it is used in a meaning that includes scattered light and diffracted light.

Note that the polarization state of each wavelength of light can be measured using a spectroradiometer or spectrometer equipped with a circularly polarizing plate. In this case, the intensity of light measured through the right-handed circularly polarizing plate corresponds to I _R and the intensity of light measured through the left-handed circularly polarizing plate corresponds to _IL . Furthermore, measurement can also be performed by attaching a circularly polarizing plate to an illuminance meter or optical spectrometer. The ratio can be measured by attaching a right-handed circularly polarized light transmitting plate and measuring the amount of right-handed circularly polarized light, and by attaching a left-handed circularly polarized light transmitting plate and measuring the amount of left-handed circularly polarized light.

P-polarized light means polarized light that vibrates in a direction parallel to the plane of incidence of light. The incident surface refers to a surface that is perpendicular to a reflective surface (such as a windshield glass surface) and that includes incident light and reflected light. In P-polarized light, the plane of vibration of the electric field vector is parallel to the plane of incidence.

The front phase difference is a value measured using AxoScan manufactured by Axometrics. Unless otherwise specified, the measurement wavelength is 550 nm. For the front phase difference, a value measured using KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments) by making light with a wavelength within the visible wavelength range incident in the normal direction of the film can also be used. When selecting a measurement wavelength, the wavelength selection filter can be replaced manually, or the measurement value can be converted using a program or the like.

"Projection image" means an image based on the projection of light from the projector used, rather than the surrounding scenery in front or the like. The projected light is observed by the viewer as a virtual image that appears above the projected image display section of the windshield glass.
"Screen image" means an image displayed on a rendering device of a projector or an image rendered by a rendering device on an intermediate image screen or the like. An image is a real image, as opposed to a virtual image.
The image and the projected light may both be a monochrome image, a multicolor image of two or more colors, or a full color image.

<<Projected image display members>>
The projected image display member of the present invention constitutes an image display section of a head-up display system. The projected image display member of the present invention is preferably an in-vehicle projected image display member used in an in-vehicle head-up display system, which is attached to a windshield glass of a vehicle or the like.
The projection image display member has visible light transmittance. Specifically, the visible light transmittance of the projection image display member is preferably 80% or more, more preferably 82% or more, and even more preferably 84% or more. By having such high visible light transmittance, even when laminated glass is made by combining glass with low visible light transmittance, it is possible to achieve visible light transmittance that meets the standards for vehicle windshield glass. can.

It is preferable that the projection image display member exhibits no substantial reflection in a wavelength range with high visibility. Specifically, when normal laminated glass and laminated glass incorporating a projection image display member are compared with respect to light from the normal direction, they must show substantially the same reflection at a wavelength of around 550 nm. is preferred. More preferably, it is preferable to exhibit substantially equivalent reflection in the visible light wavelength range of 490 to 620 nm.
"Substantially equivalent reflection" means, for example, the reflectance of natural light (unpolarized light) at the target wavelength measured from the normal direction with a spectrophotometer such as the spectrophotometer "V-670" manufactured by JASCO Corporation. This means that the difference is 10% or less. In the above wavelength range, the difference in reflectance is preferably 5% or less, more preferably 3% or less, even more preferably 2% or less, and particularly preferably 1% or less. .
Visible light transmission that meets the standards for vehicle windshield glass, even when laminated glass is combined with glass with low visible light transmittance, by showing substantially the same reflection in the wavelength range with high visibility. rate can be achieved.

The projected image display member may be in the form of a thin film, sheet, or the like. The projected image display member may be in the form of a roll or the like as a thin film before being attached to the windshield glass.

In the case where the projected image display member has a selective reflection layer described later as a preferred embodiment, it is sufficient that the member has a function as a half mirror for at least a part of the projected light. For example, it does not need to function as a half mirror for light in the entire visible light range. Further, the projection image display member may have the above-mentioned function as a half mirror for light at all incident angles, but may have the above-mentioned function for at least some light at incident angles. All you have to do is do it.

The projected image display member has a retardation layer in the projected image display section. The retardation layer is preferably a tilted retardation layer in which rod-shaped liquid crystals are tilted. As long as the projection image display member has a retardation layer, it may also include a tilted retardation layer, a support, an alignment layer, a selective reflection layer, an adhesive layer, and the like. The projected image display member will be described in more detail below.

FIG. 1 is a schematic diagram showing an example of a projection image display member according to a first aspect of the present invention. As shown in FIG. 1, the projected image display member 10 includes, as an example, a tilted retardation layer 14, a selective reflection layer 12, and a polarization conversion layer 11, which are laminated in this order on a support 15. The projection image display member 10 of the first aspect of the present invention may have at least the inclined retardation layer 14, and the support 15, the selective reflection layer 12, and the polarization conversion layer 11 may not be provided.
In this example, the support body 15 side is the incident side of the projected light, that is, the inside of the vehicle in case of vehicle-mounted use.

<Graded retardation layer>
The tilted retardation layer is a retardation layer in which a liquid crystal compound, which will be described later, is oriented obliquely with respect to the surface of the support, that is, the tilted retardation layer, and then cured. The liquid crystal compound is a rod-shaped liquid crystal compound. Since the inclined retardation layer has a rod-like liquid crystal compound that is oriented obliquely with respect to the support, the light incident from the support side and the light incident from the wavelength selective reflection layer side have different retardations.
For example, in a vehicle-mounted head-up display system, projected light with an incident angle of approximately 60 degrees enters the windshield glass and is specularly reflected by the windshield glass. Note that the incident angle is an angle with respect to the normal to the incident surface (a line perpendicular to the incident surface).
When a sloped retardation layer is provided on the inside surface of the windshield glass, the projected light enters the sloped retardation layer from the inside surface of the car, passes through it, is reflected by the windshield glass, and is reflected from the sloped retardation layer outside the car. It will enter from the plane and pass through.
Therefore, by appropriately designing the slope of the rod-shaped liquid crystal compound in the tilted retardation layer, it is possible to convert the projected light into P-polarized light and reflect it, making it possible for drivers wearing polarized sunglasses to receive the projected light. Can be visually recognized.
In the illustrated projection image display member, for example, the function as a retardation layer is different. Specifically, the inclined retardation layer does not act as a retardation layer for light incident from the support side, and acts as a λ/4 plate and λ/4 plate for light incident from the selective reflection layer side. It acts as a retardation layer such as two plates. This point will be explained in detail later.
In the present invention, any liquid crystal compound can be used for the inclined retardation layer, but a rod-shaped liquid crystal compound (hereinafter also referred to as "CLC" or "CLC compound"), a discotic liquid crystal compound (discotic liquid crystal compound, Although it is preferable to use DLC (hereinafter also referred to as "DLC" or "DLC compound"), basically, a rod-shaped liquid crystal compound is used.
Two or more kinds of rod-like liquid crystal compounds, two or more kinds of discotic liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a discotic liquid crystal compound may be used. In order to immobilize the above-mentioned liquid crystal compound, it is more preferable to use a rod-like liquid crystal compound or a discotic liquid crystal compound having a polymerizable group, and it is preferable that the liquid crystal compound has two or more polymerizable groups in one molecule. More preferred. In the case of a mixture of two or more types of liquid crystal compounds, it is preferable that at least one type of liquid crystal compound has two or more polymerizable groups in one molecule.
As the rod-shaped liquid crystal compound, for example, those described in claim 1 of Japanese Patent Application Publication No. 11-513019 and paragraphs [0026] to [0098] of JP-A-2005-289980 can be preferably used, and discotic As the liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A No. 2007-108732 and paragraphs [0013] to [0108] of JP-A No. 2010-244038 can be preferably used. However, it is not limited to these.

(Measurement of average tilt angle of tilted retardation layer)
In the tilted retardation layer, it is difficult to directly and accurately measure the tilt angle θ1 of the rod-like liquid crystal compound on one surface and the tilt angle θ2 on the other surface. Note that the tilt angle of the rod-like liquid crystal compound on the surface of the tilted retardation layer is the angle formed between the optical axis (long axis) of the rod-like liquid crystal compound and the surface of the tilted retardation layer (interface with the adjacent layer). .
Therefore, in this specification, θ1 and θ2 are calculated using the following method. Although this method does not accurately represent the actual state of the present invention, it is effective as a means of expressing the relative relationship of some optical properties of an optical film.
In this method, in order to facilitate calculation, the following two points are assumed to be the inclination angles at the two interfaces of the retardation layer (also referred to as an optically anisotropic layer).
1. It is assumed that the retardation layer is a multilayer body.
2. It is assumed that the tilt angle of each layer changes monotonically as a linear function along the thickness direction of the retardation layer.
The specific calculation method is as follows.
(1) The angle of incidence of the measurement light on the retardation layer is changed within the plane in which the tilt angle of each layer changes monotonically with a linear function along the thickness direction of the retardation layer, and retardation is achieved at three or more measurement angles. Measure the value. In order to simplify measurement and calculation, it is preferable to set the normal direction to the retardation layer at 0 degrees and measure the retardation value at three measurement angles of -40 degrees, 0 degrees, and +40 degrees. Such measurements can be performed using KOBRA-21ADH and KOBRA-WR (manufactured by Oji Scientific Instruments), transmission type ellipsometer AEP-100 (manufactured by Shimadzu Corporation), M150 and M520 (manufactured by JASCO Corporation), and ABR10A (manufactured by Uniopto Corporation). (manufactured by).
(2) In the above model, the refractive index of ordinary light of each layer is no, the refractive index of extraordinary light is ne (ne is the same value for all layers, and no is the same), and the thickness of the entire multilayer is d. shall be. Furthermore, based on the assumption that the tilt direction in each layer and the optical axis direction of one axis of that layer match, one side of the retardation layer is Fitting is performed using the inclination angle θ1 on the surface and the inclination angle θ2 on the other surface as variables, and θ1 and θ2 are calculated.
In this specification, the average tilt angle of the rod-like liquid crystal compound in the tilted retardation layer is determined as the average value of θ1 and θ2.
Here, known values such as literature values and catalog values can be used for no and ne. If the value is unknown, it can also be measured using an Abbe refractometer. The thickness of the retardation layer can be measured using an optical interference film thickness meter, a cross-sectional photograph taken with a scanning electron microscope, or the like.

In the projection image display member of the present invention, the average tilt angle of the rod-like liquid crystal compound in the tilted retardation layer is not limited, but is preferably 10 to 80 degrees (10 to 80 degrees).
By setting the average inclination angle of the rod-like liquid crystal compound in the inclined retardation layer to 10 to 80 degrees, it is easy to retain the S-polarized light that enters the inclined retardation layer from the inside of the car, and the S-polarized light that enters the inclined retardation layer from the outside of the car. This is desirable in that it is easy to convert polarized light into P-polarized light.
The average tilt angle of the rod-like liquid crystal compound in the tilted retardation layer is more preferably 20 to 70 degrees.

In addition, in the projection image display member of the present invention, the inclination direction of the rod-shaped liquid crystal compound in the inclination retardation layer is the same as the direction of incidence of the projection light from the projector 22, as conceptually shown in FIG. is preferred.
As a result, as described above, the inclined retardation layer does not act as a retardation layer for the projection light incident from the support side, but for the projection light incident from the selective reflection layer side (windshield glass side), i.e., the selective reflection layer side (windshield glass side). The projection light reflected by the reflective layer (or windshield glass) acts as a retardation layer.

In the projection image display member of the present invention, there is no limit to the retardation of the inclined retardation layer. Therefore, the inclined retardation layer may act as, for example, a λ/2 plate or a λ/4 plate with respect to light incident from the selective reflection layer (windshield glass) side. That is, the retardation of the tilted retardation layer is determined depending on the average tilt angle of the rod-shaped liquid crystal compound, the incident direction of the projected light, the selective reflection layer, etc. The phase difference that allows the light to be appropriately P-polarized may be appropriately set.
Here, the tilted retardation layer has a front retardation of 100 to 500 nm at a tilt angle of 0 degrees, which is the retardation measured by entering light from a direction perpendicular to the direction of the average tilt angle of the rod-shaped liquid crystal compound with respect to the surface. It is preferable that
In the present invention, the tilted retardation layer particularly has both a front retardation of 100 to 500 nm at a tilt angle of 0 degrees and an average tilt angle of 10 to 80 degrees for the rod-like liquid crystal compound in the tilted retardation layer. It is preferable to meet the requirements.

Specifically, the front retardation at a tilt angle of 0 degrees is the retardation of the tilted retardation layer measured as follows.
First, a plane whose rotational axis is in a direction perpendicular to the direction of the slow axis of the inclined retardation layer is assumed. The direction of the slow axis in the inclined retardation layer usually coincides with the direction of the optical axis (long axis) of the obliquely oriented rod-like liquid crystal compound.
Next, by this rotation axis, the assumed plane is tilted in the same direction as the tilt direction of the rod-shaped liquid crystal compound by the average tilt angle of the rod-shaped liquid crystal compound. Furthermore, the front retardation at an inclination angle of 0 degrees is measured by measuring the retardation by entering light from a direction (normal direction) perpendicular to this inclined plane.

It is preferable that the front retardation at a tilt angle of 0 degrees is 100 nm or more because the amount of conversion of polarized light passing through the tilted retardation layer increases. Setting the front retardation at an inclination angle of 0 degrees to 500 nm or less is preferable in that it is possible to prevent alignment defects caused by an excessively thick film of the inclined retardation layer.
The front retardation at an inclination angle of 0 degrees is more preferably 150 to 400 nm, and even more preferably 180 to 350 nm.

<Selective reflection layer>
The selective reflection layer is a layer that selectively reflects light in a wavelength-selective manner. It is preferable that the selective reflection layer exhibits selective reflection properties in a part of the visible light wavelength range. The selective reflection layer may reflect light for displaying a projected image.
The selective reflection layer may include a plurality of selective reflection layers corresponding to each wavelength range. For example, the selective reflection layer 12 shown in FIG. 1 includes a first selective reflection layer 12G that selectively reflects light with a wavelength of 500 to 650 nm, and a second selective reflection layer 12G that selectively reflects light with a wavelength of 650 to 900 nm. The first selective reflection layer 12G and the second selective reflection layer 12R are laminated on the support 15 in this order.
In the projection image display member of the present invention, the selective reflection layer 12 is not limited to a configuration having two selective reflection layers, and for example, a third selective reflection layer that wavelength-selectively reflects blue light. It may have three selective reflection layers, or it may have four or more selective reflection layers. Alternatively, the selective reflection layer may have only one layer, such as only the first selective reflection layer 12G or only the second selective reflection layer 12R.

The selective reflection layer may be a non-polarized light reflective layer (non-polarized light reflective layer) or a polarized light reflective layer (polarized light reflective layer).
Preferably, the selective reflection layer is a polarized light reflection layer. The polarized light reflecting layer is a layer that selectively reflects linearly polarized light, circularly polarized light, and elliptically polarized light. The polarized light reflective layer is preferably a circularly polarized light reflective layer (a circularly polarized reflective layer) or a linearly polarized light reflective layer (a linearly polarized reflective layer).
The circularly polarized light reflecting layer is a layer that reflects one sense of circularly polarized light and transmits the other sense at the center wavelength of selective reflection. The linearly polarized light reflecting layer is a layer that reflects linearly polarized light in one polarization direction at the center wavelength of selective reflection and transmits linearly polarized light in a polarization direction perpendicular to the above-mentioned polarization direction.
The polarized light reflective layer can transmit polarized light that is not reflected, and can transmit some light even in the wavelength range where the selective reflective layer shows reflection. Therefore, it is preferable because the color tone of the light transmitted through the projection image display member is less likely to be deteriorated and the visible light transmittance is also less likely to be reduced.
The selective reflection layer preferably includes a cholesteric liquid crystal layer as a circularly polarized light reflection layer, and may include two or more cholesteric liquid crystal layers.
The center wavelength of the light reflected by the selective reflection layer (selective reflection center wavelength) is preferably 500 to 650 nm and/or 650 to 900 nm, and 530 to 630 nm and/or 670 nm, from the viewpoint of color and visible light transmittance. The wavelength is more preferably 550 to 610 nm and/or 680 to 800 nm.

When the selective reflection layer includes a cholesteric liquid crystal layer, the projection image display member preferably includes a retardation layer. By using a retardation layer in combination with a cholesteric liquid crystal layer, clear projected light can be displayed. By adjusting the front phase difference and the direction of the slow axis, it is possible to provide a projected image display member that can obtain high brightness in a head-up display system and can also suppress double images.
Here, it is known that in the cholesteric liquid crystal layer, the center wavelength of reflection shifts to the shorter wavelength side with respect to oblique light. The shift of the center wavelength of reflection to the shorter wavelength side is called a blue shift. In the case of oblique light, a blue shift occurs in the cholesteric liquid crystal layer because the difference in optical path length between each layer becomes smaller due to optical interference. Therefore, when observed from an oblique direction, a blue shift occurs. For this reason, when the selective reflection layer is composed of a cholesteric liquid crystal layer, it is possible to compensate in advance for the shift of the center wavelength of reflection to the short wavelength side and shift the center wavelength of reflection in front of the selective reflection layer to the long wavelength side. desirable. The center wavelength of the oblique light is the center wavelength of the oblique light, where the angle from the front when the oblique light propagates through the selective reflection layer is θ, and the center wavelength of the oblique light = center wavelength at the front × cos θ. It is possible to adopt a configuration in which the center wavelength is shifted. The wavelength range of the selective reflection layer 12 described above is set in consideration of blue shift.

[Cholesteric liquid crystal layer]
The cholesteric liquid crystal layer means a layer in which a cholesteric liquid crystal phase is fixed.
The cholesteric liquid crystal layer may be any layer in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained, and typically, the polymerizable liquid crystal compound is brought into the cholesteric liquid crystal phase alignment state and then exposed to ultraviolet rays. Any layer may be used as long as it is polymerized and cured by heating or the like to form a layer with no fluidity, and at the same time, the layer changes to a state in which the orientation form does not change due to an external field or external force. Note that in the cholesteric liquid crystal layer, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal compound in the layer does not need to exhibit liquid crystallinity anymore. For example, the polymerizable liquid crystal compound may have a high molecular weight due to a curing reaction and may no longer have liquid crystallinity.

It is known that the cholesteric liquid crystal phase exhibits circularly polarized light selective reflectivity in which it selectively reflects circularly polarized light of either right-handed or left-handed circularly polarized senses and transmits the other sense of circularly polarized light. .
Many films formed from compositions containing polymerizable liquid crystal compounds have been known as films including a layer in which a cholesteric liquid crystal phase that exhibits selective reflection of circularly polarized light is fixed. You can refer to the technology.

The center wavelength λ of selective reflection of the cholesteric liquid crystal layer (center wavelength λ of selective reflection) depends on the pitch P (=period of the helix) of the helical structure in the cholesteric liquid crystal phase, and the average refractive index n of the cholesteric liquid crystal layer and λ=n According to the relationship ×P. As can be seen from this equation, the center wavelength of selective reflection can be adjusted by adjusting the n value and the P value.
In other words, the pitch P of the helical structure (one pitch of the helix) is the length in the direction of the helical axis corresponding to one turn of the helix. (long axis direction) is the length in the helical axis direction of rotation of 360 degrees. The helical axis direction of a normal cholesteric liquid crystal layer coincides with the thickness direction of the cholesteric liquid crystal layer.

The selective reflection center wavelength and half-value width of the cholesteric liquid crystal layer can be determined as follows.
When the reflection spectrum of the cholesteric liquid crystal layer (measured from the normal direction of the cholesteric liquid crystal layer) was measured using a spectrophotometer (manufactured by JASCO Corporation, V-670), a peak of decrease in transmittance was observed in the selective reflection band. It will be done. Of the two wavelengths that give the intermediate (average) transmittance between the minimum transmittance at this peak and the transmittance before decreasing, the value of the wavelength on the shorter wavelength side is λ l (nm), and the value of the wavelength on the longer wavelength side is λ _l (nm). is λ _h (nm), the center wavelength λ and half-value width Δλ of selective reflection can be expressed by the following formula.
λ=(λ _l +λ _h )/2Δλ=(λ _h −λ _l )
The center wavelength of selective reflection determined as described above substantially coincides with the wavelength at the center of gravity of the reflection peak of the circularly polarized light reflection spectrum measured from the normal direction of the cholesteric liquid crystal layer.

In the head-up display system described below, by using the windshield glass so that light is incident obliquely, the reflectance on the surface of the glass plate on the projection light incident side can be lowered. At this time, light also obliquely enters the cholesteric liquid crystal layer. For example, light incident in air with a refractive index of 1 at an angle of 45 to 70 degrees with respect to the normal line of the projected image display section will be transmitted through a cholesteric liquid crystal layer with a refractive index of about 1.61 at an angle of about 26 to 36 degrees. do. In this case, the reflected wavelength shifts to the shorter wavelength side. In a cholesteric liquid crystal layer where the center wavelength of selective reflection is λ, the center wavelength of selective reflection is defined _as When λ _d , λ _d is expressed by the following formula.
λ _d = λ×cos θ ₂

Therefore, when θ ₂ is 2 to 36 degrees, a cholesteric liquid crystal layer having a center wavelength of selective reflection in the range of 650 to 780 nm can reflect projected light in the range of 520 to 695 nm.
Since such a wavelength range is a wavelength range with high visibility, it has a high contribution to the brightness of the projected light, and as a result, high brightness of the projected light can be realized.

Since the pitch of the cholesteric liquid crystal phase depends on the type of chiral agent used together with the polymerizable liquid crystal compound or its concentration, a desired pitch can be obtained by adjusting these. For measuring the helical sense and pitch, use the methods described in "Introduction to Liquid Crystal Chemistry Experiments," edited by the Japan Liquid Crystal Society, published by Sigma Publishing, 2007, p. 46, and "Liquid Crystal Handbook," Liquid Crystal Handbook Editorial Committee, Maruzen, p. 196. be able to.

Further, in the projection image display member, it is preferable that the cholesteric liquid crystal layers are arranged in descending order of the central wavelength of selective reflection when viewed from the viewing side (inside the vehicle).

As each cholesteric liquid crystal layer, a cholesteric liquid crystal layer whose spiral sense is either right or left is used. The sense of circularly polarized light reflected by the cholesteric liquid crystal layer corresponds to the sense of spiral. The helical senses of the cholesteric liquid crystal layers having different center wavelengths of selective reflection may all be the same, or may include different senses. However, it is preferable that the plurality of cholesteric liquid crystal layers all have the same helical sense.

Further, when the projection image display member has cholesteric liquid crystal layers that exhibit selective reflection in the same or overlapping wavelength range, it is preferable that the cholesteric liquid crystal layers do not include cholesteric liquid crystal layers with different helical senses. This is to prevent the transmittance of the projection image display member in a specific wavelength range from decreasing to less than 50%, for example.

The half-width Δλ (nm) of the selective reflection band exhibiting selective reflection depends on the birefringence Δn of the liquid crystal compound and the above-mentioned pitch P, and follows the relationship Δλ=Δn×P. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Adjustment of Δn can be performed by adjusting the type or mixing ratio of the polymerizable liquid crystal compound, or by controlling the temperature at the time of fixing the orientation.
In order to form one type of cholesteric liquid crystal layer having the same selective reflection center wavelength, a plurality of cholesteric liquid crystal layers having the same pitch P and the same helical sense may be laminated. By stacking cholesteric liquid crystal layers with the same pitch P and the same helical sense, it is possible to increase the circularly polarized light selectivity at a specific wavelength.

The selective reflection layer 12 preferably has a cholesteric liquid crystal layer with a reflection wavelength band of 540 to 850 nm and a half width of 150 nm or more. When the half width of the selective reflection layer 12 is 150 nm or more, the cholesteric liquid crystal layer having the center wavelength of selective reflection becomes a broadband selective reflection layer, and the brightness of the image can be increased.

When laminating multiple cholesteric liquid crystal layers, separately prepared cholesteric liquid crystal layers may be laminated using an adhesive or the like, or the polymerizable liquid crystal layer may be laminated directly onto the surface of the cholesteric liquid crystal layer formed by the method described below. Although the steps of applying a liquid crystal composition containing a compound and the like and repeating alignment and fixing may be repeated, the latter is preferred.
By forming the next cholesteric liquid crystal layer directly on the surface of the previously formed cholesteric liquid crystal layer, the alignment direction of the liquid crystal molecules on the air interface side of the previously formed cholesteric liquid crystal layer and the cholesteric liquid crystal layer formed thereon can be adjusted. This is because the alignment directions of the liquid crystal molecules on the lower side match, and the polarization characteristics of the stacked body of cholesteric liquid crystal layers become good. Further, interference unevenness that may be caused by uneven thickness of the adhesive layer is not observed.

The thickness of the cholesteric liquid crystal layer is preferably 0.2 to 10 μm, more preferably 0.3 to 8.0 μm, and even more preferably 0.4 to 6.0 μm. Further, in the case of having a plurality of cholesteric liquid crystal layers, the total thickness of the cholesteric liquid crystal layers in the projection image display member is preferably 1.0 to 30 μm, more preferably 1.5 to 25 μm, and 2.0 to 20 μm. More preferred.
In the projection image display member, high visible light transmittance can be maintained without reducing the thickness of the cholesteric liquid crystal layer.

(Method for producing cholesteric liquid crystal layer)
The material and method for manufacturing the cholesteric liquid crystal layer will be described below.
Examples of the material used to form the cholesteric liquid crystal layer include a liquid crystal composition containing a polymerizable liquid crystal compound and a chiral agent (optically active compound). The above-mentioned liquid crystal composition, which is further mixed with a surfactant or a polymerization initiator as necessary and dissolved in a solvent, is applied to the support, the alignment layer, the lower cholesteric liquid crystal layer, etc., and after cholesteric alignment ripening. A cholesteric liquid crystal layer can be formed by fixing the liquid crystal composition by curing it.

(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound may be a rod-like liquid crystal compound or a discotic liquid crystal compound, but is preferably a rod-like liquid crystal compound.
An example of the rod-shaped polymerizable liquid crystal compound that forms the cholesteric liquid crystal layer is a rod-shaped nematic liquid crystal compound. Rod-shaped nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines. , phenyldioxanes, tolans, and alkenylcyclohexylbenzonitrile are preferably used. Not only low-molecular liquid crystal compounds but also high-molecular liquid crystal compounds can be used.

A polymerizable liquid crystal compound can be obtained by introducing a polymerizable group into a liquid crystal compound. Examples of the polymerizable group include unsaturated polymerizable groups, epoxy groups, and aziridinyl groups, with unsaturated polymerizable groups being preferred, and ethylenically unsaturated polymerizable groups being particularly preferred. The polymerizable group can be introduced into the molecules of the liquid crystal compound by various methods. The number of polymerizable groups that the polymerizable liquid crystal compound has is preferably 1 to 6, more preferably 1 to 3 in one molecule.
Examples of polymerizable liquid crystal compounds include Makromol. Chem. , vol. 190, p. 2255 (1989), Advanced Materials vol. 5, p. 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication No. 1995/22586, International Publication No. 1995/24455, International Publication No. 1997/00600, International Publication No. 1998/23580, International Publication No. 1998/52905, JP-A-1-272551, JP-A-6-16616 JP-A No. 7-110469, JP-A No. 11-80081, and JP-A No. 2001-328973. Two or more types of polymerizable liquid crystal compounds may be used together. When two or more types of polymerizable liquid crystal compounds are used together, the alignment temperature can be lowered.

Further, the amount of the polymerizable liquid crystal compound added in the liquid crystal composition is preferably 80 to 99.9% by mass, and 85 to 99.5% by mass based on the solid mass of the liquid crystal composition (mass excluding solvent). % is more preferable, and 90 to 99% by mass is even more preferable.

In order to improve the visible light transmittance, the first selective reflection layer 12G may have a low Δn. The low Δn first selective reflection layer 12G can be formed using a low Δn polymerizable liquid crystal compound. The low Δn polymerizable liquid crystal compound will be specifically explained below.

(Low Δn polymerizable liquid crystal compound)
A narrow band selective reflection layer can be obtained by forming a cholesteric liquid crystal phase using a low Δn polymerizable liquid crystal compound and forming a fixed film. Examples of low Δn polymerizable liquid crystal compounds include WO 2015/115390, WO 2015/147243, WO 2016/035873, JP 2015-163596, and JP 2016-53149. Examples thereof include the compounds described in the above publication. Regarding the liquid crystal composition that provides a selective reflection layer with a small half width, reference can also be made to the description in International Publication No. 2016/047648.

It is also preferable that the liquid crystal compound is a polymerizable compound represented by the following formula (I) described in International Publication No. 2016/047648.

In formula (I), A represents a phenylene group which may have a substituent or a trans-1,4-cyclohexylene group which may have a substituent, L is a single bond, and -CH ₂ O-, -OCH ₂ -, -(CH ₂ ) ₂ OC(=O)-, -C(=O)O(CH ₂ ) ₂ -, -C(=O)O-, -OC(=O) -, -OC(=O)O-, -CH=CH-C(=O)O-, and -OC(=O)-CH=CH-, where m is represents an integer from 3 to 12, and Sp ¹ and Sp ² each independently represent a single bond, a straight chain or branched alkylene group having 1 to 20 carbon atoms, and a straight chain or branched alkylene group having 1 to 20 carbon atoms. One or more -CH ₂ - is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or - It represents a linking group selected from the group consisting of groups substituted with C(=O)O-, and Q ¹ and Q ² are each independently a hydrogen atom or a group represented by the following formulas Q-1 to Q-5. represents a polymerizable group selected from the group consisting of groups, provided that either one of Q ¹ and Q ² represents a polymerizable group.

In formula (I), the phenylene group is preferably a 1,4-phenylene group.
When the phenylene group and the trans-1,4-cyclohexylene group are referred to as "may have a substituent", the substituent is not particularly limited, and includes, for example, an alkyl group, a cycloalkyl group, an alkoxy group, an alkyl ether. Examples include substituents selected from the group consisting of a group consisting of a group, an amide group, an amino group, a halogen atom, and a group constituted by a combination of two or more of the above-mentioned substituents. Further, examples of the substituent include a substituent represented by -C(=O)-X ³ -Sp ³ -Q ³ described below. The phenylene group and trans-1,4-cyclohexylene group may have 1 to 4 substituents. When it has two or more substituents, the two or more substituents may be the same or different.

The alkyl group may be either linear or branched. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, and neopentyl group. 1,1-dimethylpropyl group, n-hexyl group, isohexyl group, linear or branched heptyl group, octyl group, nonyl group, decyl group, undecyl group, or dodecyl group. The above explanation regarding an alkyl group also applies to an alkoxy group containing an alkyl group. Further, specific examples of the alkylene group when referring to an alkylene group include divalent groups obtained by removing one arbitrary hydrogen atom from each of the above-mentioned examples of the alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The number of carbon atoms in the cycloalkyl group is preferably 3 to 20, more preferably 5 or more, and preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

In particular, the substituents that the phenylene group and the trans-1,4-cyclohexylene group may have include an alkyl group, an alkoxy group, and a group consisting of -C(=O)-X ³ -Sp ³ -Q ³ Substituents selected from are preferred. Here, X ³ represents a single bond, -O-, -S-, or -N(Sp ⁴ -Q ⁴ )-, or represents a nitrogen atom forming a ring structure together with Q ³ and Sp ³ . show. Sp ³ and Sp ⁴ each independently represent a single bond, a linear or branched alkylene group having 1 to 20 carbon atoms, and one or more - in the linear or branched alkylene group having 1 to 20 carbon atoms. CH ₂ - is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O- Indicates a linking group selected from the group consisting of substituted groups.

Q ³ and Q ⁴ each independently represent a hydrogen atom, a cycloalkyl group, or a cycloalkyl group in which one or more -CH ₂ - is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O-, or from a group represented by formula Q-1 to formula Q-5 represents any polymerizable group selected from the group consisting of:

In the cycloalkyl group, one or more -CH ₂ - is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O) Specific examples of the group substituted with - or -C(=O)O- include a tetrahydrofuranyl group, a pyrrolidinyl group, an imidazolidinyl group, a pyrazolidinyl group, a piperidyl group, a piperazinyl group, and a morpholinyl group. . The substitution position is not particularly limited. Among these, a tetrahydrofuranyl group is preferred, and a 2-tetrahydrofuranyl group is particularly preferred.

In formula (I), L is a single bond, -CH ₂ O-, -OCH _2- , -(CH ₂ ) ₂ OC(=O)-, -C(=O)O(CH ₂ ) ₂ -, - C(=O)O-, -OC(=O)-, -OC(=O)O-, -CH=CH-C(=O)O-, and -OC(=O)-CH=CH - represents a linking group selected from the group consisting of. L is preferably -C(=O)O- or -OC(=O)-. m-1 L's may be the same or different from each other.

Sp ¹ and Sp ² each independently represent a single bond, a linear or branched alkylene group having 1 to 20 carbon atoms, and one or more - in the linear or branched alkylene group having 1 to 20 carbon atoms. CH ₂ - is -O-, -S-, -NH-, -N(CH ₃ )-, -C(=O)-, -OC(=O)-, or -C(=O)O- Indicates a linking group selected from the group consisting of substituted groups. Sp ¹ and Sp ² each independently have a carbon number of 1 to which a linking group selected from the group consisting of -O-, -OC(=O)-, and -C(=O)O- is bonded to both ends, respectively. A group selected from the group consisting of a linear alkylene group having 10 carbon atoms, -OC(=O)-, -C(=O)O-, -O-, and a linear alkylene group having 1 to 10 carbon atoms. The linking group is preferably a linking group formed by combining one or more of the following, and is preferably a linear alkylene group having 1 to 10 carbon atoms with -O- bonded to both ends.

Q ¹ and Q ² each independently represent a hydrogen atom or a polymerizable group selected from the group consisting of the groups represented by the above formulas Q-1 to Q-5, provided that Q ¹ and Q ² Either one represents a polymerizable group.
The polymerizable group is preferably an acryloyl group (formula Q-1) or a methacryloyl group (formula Q-2).

In formula (I), m represents an integer of 3 to 12, preferably an integer of 3 to 9, more preferably an integer of 3 to 7, and even more preferably an integer of 3 to 5. .

The polymerizable compound represented by formula (I) has at least one phenylene group which may have a substituent as A and a trans-1,4-cyclohexylene group which may have a substituent. It is preferable to include at least one. The polymerizable compound represented by formula (I) preferably contains 1 to 4 trans-1,4-cyclohexylene groups, which may have a substituent, and preferably contains 1 to 3 trans-1,4-cyclohexylene groups as A. is more preferable, and it is even more preferable to contain 2 or 3 pieces. Further, the polymerizable compound represented by formula (I) preferably contains one or more phenylene groups, which may have a substituent, as A, more preferably 1 to 4, and 1 to 4. It is more preferable to contain three pieces, and it is especially preferable to contain two or three pieces.

In formula (I), when mc is the number of trans-1,4-cyclohexylene groups represented by A divided by m, it is preferable that 0.1<mc<0.9, and 0 It is more preferable that .3<mc<0.8, and even more preferable that 0.5<mc<0.7. A polymerizable compound represented by formula (I) in which the liquid crystal composition satisfies 0.5<mc<0.7 and a polymerizable compound represented by formula (I) in which 0.1<mc<0.3. It is also preferable to include.

Specifically, examples of the polymerizable compound represented by formula (I) include compounds described in paragraphs 0051 to 0058 of International Publication No. 2016/047648, as well as JP-A No. 2013-112631, JP-A No. 2010- No. 70543, Japanese Patent No. 4725516, International Publication No. 2015/115390, International Publication No. 2015/147243, International Publication No. 2016/035873, Japanese Patent Application Publication No. 2015-163596, and Japanese Patent Application Publication No. 2016-53149 Examples include the compounds described in .

(Chiral agent: optically active compound)
A chiral agent has a function of inducing a helical structure of a liquid crystal compound in a cholesteric liquid crystal phase. Chiral compounds may be selected depending on the purpose, since the helical sense or helical pitch induced by the compound differs depending on the compound.
There are no particular limitations on the chiral agent, and known compounds can be used. Examples of chiral agents include the Liquid Crystal Device Handbook (Chapter 3, Section 4-3, Chiral Agents for TN and STN, p. 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), and JP-A No. 2003-287623. , JP 2002-302487, JP 2002-80478, JP 2002-80851, JP 2010-181852, and JP 2014-034581.

Chiral agents generally contain asymmetric carbon atoms, but axially asymmetric compounds or planar asymmetric compounds that do not contain asymmetric carbon atoms can also be used as chiral agents. Examples of axially asymmetric compounds or planar asymmetric compounds include binaphthyl, helicene, paracyclophane, and derivatives thereof.
The chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound results in a repeating unit derived from the polymerizable liquid crystal compound and a repeating unit derived from the chiral agent. repeating units can be formed. In this embodiment, the polymerizable group possessed by the polymerizable chiral agent is preferably the same type of group as the polymerizable group possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and preferably an ethylenically unsaturated polymerizable group. Particularly preferred.
Moreover, a liquid crystal compound may be sufficient as a chiral agent.

As the chiral agent, isosorbide derivatives, isomannide derivatives, or binaphthyl derivatives can be preferably used. As the isosorbide derivative, commercially available products such as LC756 manufactured by BASF may be used.
The content of the chiral agent in the liquid crystal composition is preferably 0.01 to 200 mol%, more preferably 1 to 30 mol%, based on the amount of the polymerizable liquid crystal compound.

(Polymerization initiator)
It is preferable that the liquid crystal composition contains a polymerization initiator. In the embodiment in which the polymerization reaction is advanced by ultraviolet irradiation, the polymerization initiator used is preferably a photopolymerization initiator that can initiate the polymerization reaction by ultraviolet irradiation. Examples of photopolymerization initiators include α-carbonyl compounds (described in U.S. Pat. No. 2,367,661 and U.S. Pat. No. 2,367,670), acyloin ether (described in U.S. Pat. No. 2,448,828), and α-hydrocarbons. Substituted aromatic acyloin compounds (described in U.S. Pat. No. 2,722,512), polynuclear quinone compounds (described in U.S. Pat. No. 3,046,127 and U.S. Pat. No. 2,951,758), triarylimidazole dimer and p-aminophenyl ketone. combination (described in US Pat. No. 3,549,367), acridine and phenazine compounds (described in JP-A No. 60-105667, US Pat. No. 4,239,850), acylphosphine oxide compounds (described in JP-A-63-40799, JP-A-5-29234, JP-A-10-95788, JP-A-10-29997, JP-A-2001-233842, JP-A-2000-80068, JP-A-2006-342166, JP-A-2006-342166 2013-114249, JP 2014-137466, JP 4223071, JP 2010-262028, JP 2014-500852), oxime compounds (JP 2000-66385, JP 2014-500852) 4,454,067) and oxadiazole compounds (described in US Pat. No. 4,212,970). For example, the descriptions in paragraphs 0500 to 0547 of JP-A No. 2012-208494 can also be referred to.

As the polymerization initiator, it is also preferable to use an acylphosphine oxide compound or an oxime compound.
As the acylphosphine oxide compound, for example, commercially available IRGACURE810 (compound name: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) manufactured by BASF Japan Co., Ltd. can be used. Examples of oxime compounds include IRGACURE OXE01 (manufactured by BASF), IRGACURE OXE02 (manufactured by BASF), TR-PBG-304 (manufactured by Changzhou Strong Electronics New Materials Co., Ltd.), Adeka Arcles NCI-831, and Adeka Arcles NCI-930. (manufactured by ADEKA), and ADEKA Arkles NCI-831 (manufactured by ADEKA) can be used.
One type of polymerization initiator may be used, or two or more types may be used in combination.
The content of the photopolymerization initiator in the liquid crystal composition is preferably 0.1% by mass to 20% by mass, and 0.5% by mass to 5% by mass, based on the content of the polymerizable liquid crystal compound. It is even more preferable.

(Crosslinking agent)
The liquid crystal composition may optionally contain a crosslinking agent in order to improve film strength and durability after curing. As the crosslinking agent, those that are cured by ultraviolet rays, heat, moisture, etc. can be suitably used.
The crosslinking agent is not particularly limited and can be selected as appropriate depending on the purpose; for example, polyfunctional acrylate compounds such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; glycidyl (meth)acrylate; Epoxy compounds such as acrylate and ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4-bis(ethyleneiminocarbonylamino)diphenylmethane; Isocyanate compounds such as hexamethylene diisocyanate and biuret-type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; alkoxysilane compounds such as vinyltrimethoxysilane and N-(2-aminoethyl)3-aminopropyltrimethoxysilane, etc. Can be mentioned. Further, a known catalyst can be used depending on the reactivity of the crosslinking agent, and productivity can be improved in addition to improving membrane strength and durability. These may be used alone or in combination of two or more.
The content of the crosslinking agent is preferably 3 to 20% by mass, more preferably 5 to 15% by mass. By setting the content of the crosslinking agent to 3% by mass or more, it is possible to obtain the effect of improving crosslinking density, and by setting the content of the crosslinking agent to 20% by mass or less, a decrease in the stability of the cholesteric liquid crystal layer can be prevented. It can be prevented.
Note that "(meth)acrylate" is used to mean "one or both of acrylate and methacrylate."

(Orientation control agent)
An alignment control agent that contributes to stably or rapidly forming a cholesteric liquid crystal layer with planar alignment may be added to the liquid crystal composition. Examples of alignment control agents include fluorine (meth)acrylate polymers described in paragraphs [0018] to [0043] of JP-A No. 2007-272185, and paragraphs [0031] to [0034] of JP-A-2012-203237. ], compounds represented by formulas (I) to (IV) described in JP-A No. 2013-113913, and the like.
In addition, as the alignment control agent, one type may be used alone, or two or more types may be used in combination.
Examples of fluorine compounds used as alignment control agents include the compounds described in paragraphs [0086] to [0101] of Patent Document 1 (International Publication No. 2014/073616) (vertical alignment agent on the alignment film interface side); , the compounds described in paragraphs [0102] to [0113] of the same document (air interface side vertical alignment agent), the contents of which are incorporated herein by reference.
In addition, examples of fluorine compounds used as surfactants include compounds described in paragraphs [0028] to [0056] of JP-A No. 2001-330725, and [0069] of JP-A No. 2005-062673. Examples include the compounds described in paragraphs [0126] and the like, the contents of which are incorporated herein by reference.

In addition, in the present invention, as another example of the fluorine compound, the polymer defined in claim 14 of JP-A-2008-257205 (that is, the structural unit represented by the following general formula (A) and the following general A polymer containing a structural unit represented by formula (B)) and a tilt angle control agent defined in claim 15 of the same publication (i.e., a structural unit represented by the following general formula (A) and a fluorofat Specific examples thereof include the polymers described in paragraphs [0023] to [0063] of the same publication, the contents of which are described in this specification. incorporated into the book as a reference.

Here, in the general formula (A), Mp represents a trivalent group constituting a part of the main chain of the polymer, L represents a single bond or a divalent linking group, and X represents a substituted or unsubstituted aromatic group. represents a group fused ring functional group; in the general formula (B), Mp' represents a trivalent group constituting a part of the main chain of the polymer, L' represents a single bond or a divalent linking group, and Rf represents a substituent containing at least one fluorine atom.

In the present invention, the fluorine compound is preferably a polymer containing at least a structural unit derived from a fluoroaliphatic group-containing monomer.
The weight average molecular weight of such a polymer is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 10,000 to 100,000.
Here, the weight average molecular weight refers to a polystyrene (PS) equivalent value measured using gel permeation chromatography (GPC).

The amount of the alignment control agent added in the liquid crystal composition is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, and 0.02 to 1% by mass based on the total mass of the polymerizable liquid crystal compound. % by weight is particularly preferred.

(Other additives)
In addition, the liquid crystal composition may contain at least one kind selected from various additives such as a surfactant for adjusting the surface tension of the coating film and making the thickness uniform, and a polymerizable monomer. In addition, in the liquid crystal composition, if necessary, polymerization inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, coloring materials, metal oxide fine particles, etc. may be added within a range that does not deteriorate optical performance. It can be added with.

The cholesteric liquid crystal layer is prepared by preparing a liquid crystal composition in which a polymerizable liquid crystal compound, a polymerization initiator, a chiral agent, a surfactant, etc. added as necessary are dissolved in a solvent, on a support, an alignment layer, or in advance. A cholesteric liquid crystal layer with fixed cholesteric regularity is obtained by applying actinic rays to the coating film to polymerize the cholesteric liquid crystal composition. can be formed. Note that a laminated film consisting of a plurality of cholesteric liquid crystal layers can be formed by repeatedly performing the above-described manufacturing process for cholesteric liquid crystal layers.

(solvent)
The solvent used for preparing the liquid crystal composition is not particularly limited and can be appropriately selected depending on the purpose, but organic solvents are preferably used.
The organic solvent is not particularly limited and can be selected as appropriate depending on the purpose, such as ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, and ethers. etc. These may be used alone or in combination of two or more. Among these, ketones are particularly preferred in consideration of the burden on the environment.

(coating, orientation, polymerization)
The method of applying the liquid crystal composition to the support, the alignment layer, the lower cholesteric liquid crystal layer, etc. is not particularly limited and can be selected as appropriate depending on the purpose. For example, wire bar coating method, curtain coating method, Examples include extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, spin coating method, dip coating method, spray coating method, and slide coating method. It can also be carried out by transferring a liquid crystal composition separately coated onto a support. By heating the applied liquid crystal composition, liquid crystal molecules are aligned. The heating temperature is preferably 200°C or lower, more preferably 130°C or lower. This alignment treatment yields an optical thin film in which the polymerizable liquid crystal compound is twisted and oriented so that the helical axis is substantially perpendicular to the film surface.

The liquid crystal composition can be cured by further polymerizing the oriented liquid crystal compound. The polymerization may be thermal polymerization or photopolymerization using light irradiation, but photopolymerization is preferred. It is preferable to use ultraviolet light for light irradiation. The irradiation energy is preferably 20 mJ/cm ² to 50 J/cm ² , more preferably 100 mJ/cm ² to 1,500 mJ/cm ² .
In order to promote the photopolymerization reaction, light irradiation may be performed under heating conditions or under a nitrogen atmosphere. The irradiation ultraviolet wavelength is preferably 350 to 430 nm. From the viewpoint of stability, the polymerization reaction rate is preferably higher, preferably 70% or more, and more preferably 80% or more. The polymerization reaction rate can be determined by measuring the consumption rate of polymerizable functional groups by infrared absorption spectrum.

[Linearly polarized light reflective layer]
As the selective reflection layer, a linearly polarized light reflective layer may be used as long as it has the same wavelength selective reflection characteristics as the circularly polarized light reflective layer described above.
Examples of the linearly polarized light reflecting layer include a polarizer in which thin films having different refractive index anisotropies are laminated. Such a polarizer has high visible light transmittance similar to the cholesteric liquid crystal layer, and can reflect obliquely incident projection light at a wavelength with high visibility when used in a head-up display system.

As a polarizer in which thin films having different refractive index anisotropies are laminated, for example, those described in Japanese Patent Publication No. 9-506837 can be used. Specifically, polarizers can be formed using a wide variety of materials when processed under conditions selected to obtain a refractive index relationship. Generally, it is necessary for one of the first materials to have a different index of refraction in a chosen direction than the second material. This difference in refractive index can be achieved in a variety of ways, including stretching, extrusion, or coating during or after film formation. Additionally, it is preferred that the two materials have similar rheological properties (eg, melt viscosity) so that they can be coextruded.
A commercially available polarizer can be used as a polarizer in which thin films having different refractive index anisotropies are laminated. As a commercially available product, a laminate of a reflective polarizing plate and a temporary support may be used. Examples of commercially available products include commercially available optical films sold as DBEF (registered trademark) (manufactured by 3M Company) and APF (Advanced Polarizing Film (manufactured by 3M Company)).
The thickness of the reflective polarizing plate is preferably 2 to 50 μm, more preferably 8 to 30 μm.
In order to make the front transmittance 70% or more, the difference between the first maximum refractive index and the second refractive index is preferably 0.1 or more, and the number of layers is preferably 4 to 20.

[Non-polarized reflective layer]
As the selective reflection layer, a non-polarized light reflection layer may be used as long as it has the same wavelength-selective reflection characteristics as the circularly polarized light reflection layer described above.
An example of the non-polarized light reflecting layer is an isotropic dielectric multilayer film. The isotropic dielectric multilayer film is formed of a material in which the refractive indexes of the high refractive index film and the low refractive index film in the above-mentioned linearly polarized light reflecting layer are isotropic. A linearly polarized light reflective layer strongly reflects a specific linearly polarized light, whereas an isotropic dielectric multilayer film shows similar reflection for any polarized light.

<Polarization conversion layer>
The projection image display member shown in FIG. 1 has a polarization conversion layer as a preferred embodiment.
When the projection image display member has a polarization conversion layer, at least one retardation layer, at least one selective reflection layer, and at least one polarization conversion layer are provided in this order. In particular, as a projection image display member, as shown in FIG. 1, the inclined retardation layer 14, the selective reflection layer 12, and the polarization conversion layer 11 are arranged in this order from the viewing side, that is, the incident side of the projection light. Just set it up.
By including the polarization conversion layer in the projection image display member, it is possible to improve the suitability for external light of polarized sunglasses that cut S-polarized light, which is the main component of glare from reflected light from the hood of an oncoming car or a puddle. That is, by including the polarization conversion layer in the projection image display member, the suitability of the polarized sunglasses to external light can be improved, and the polarized sunglasses can suitably block the S-polarized light incident from the outside that causes glare.

An example of the polarization conversion layer is a layer in which a helical alignment structure of a liquid crystal compound is fixed.
As a layer in which a helical alignment structure of a liquid crystal compound is fixed, the following relational expression (i) and ( A polarization conversion layer that satisfies ii) is preferred.
(i) 0.3≦x≦2.0
(ii) 0.5≦y≦7.0
The pitch of the helical structure (one helical pitch) is the length in the helical axis direction in which the director of the liquid crystal compound constituting the helical alignment structure rotates 360 degrees, similar to the cholesteric liquid crystal layer. In the polarization conversion layer in which the helical alignment structure of the liquid crystal compound is fixed, one pitch in which the director of the liquid crystal compound rotates 360 degrees is defined as one pitch.
That is, the polarization conversion layer in which the helical alignment structure of the liquid crystal compound is fixed preferably has a pitch number of 0.3 to 2.0 and a film thickness of 0.5 to 7.0 μm. It is more preferable that the polarization conversion layer has a pitch number of 0.4 to 1.5 and a film thickness of 0.8 to 6.0 μm, and a pitch number of 0.5 to 1.0 and a film thickness of 1.0 μm. More preferably, the thickness is from 0 to 5.0 μm.

The reason why the suitability of polarized sunglasses against external light can be improved by providing a polarization conversion layer in which a helical alignment structure of a liquid crystal compound is fixed is that the polarization conversion layer has a helical structure similar to a cholesteric liquid crystal phase. This is because it exhibits optical rotation and birefringence for visible light, which has a shorter wavelength than the reflection peak wavelength in the infrared region, so polarization in the visible region can be controlled.
As mentioned above, polarized sunglasses block S-polarized light, which is the main component of glare from reflected light from the hood of an oncoming car or a puddle. Here, when the S-polarized light incident from the outside of the windshield glass passes through the projection image display member including the retardation layer or the selective reflection layer, the polarization changes significantly, and the transmitted light cannot be cut by polarized sunglasses. Contains polarized light components. On the other hand, a polarization conversion layer in which a helical alignment structure of a liquid crystal compound is fixed is provided in a projection image display member, and the pitch number of the polarization conversion layer is adjusted so that changes in S-polarized light incident from the outside can be optically compensated for. By controlling the film thickness, S-polarized light incident from the outside can be transmitted through the projection image display member as S-polarized light. As a result, the polarized sunglasses can block S-polarized light incident from the outside, and the suitability of the polarized sunglasses against external light can be improved.

In the projection light display member of the present invention, the polarization conversion layer is not limited to a polarization conversion layer in which a helical alignment structure of a liquid crystal compound is fixed, and a retardation layer having a front retardation of 100 to 500 nm may also be used. Available as layers.
By providing a retardation layer with a front retardation of 100 to 500 nm as a polarization conversion layer, it compensates for changes in S-polarized light incident from the outside, similar to the polarization conversion layer that fixes the helical alignment structure of the liquid crystal compound described above. By transmitting the S-polarized light through the projection image display member, the suitability of the polarized sunglasses to outside light can be improved.
The front retardation of the retardation layer as a polarization conversion layer is preferably 105 to 400 nm, more preferably 110 to 300 nm.

<Other layers>
The projection image display member may include layers other than the selective reflection layer, the polarization conversion layer, and the inclined retardation layer.
All other layers are preferably transparent in the visible light region.
Further, it is preferable that all other layers have low birefringence. Low birefringence means that the front phase difference is 10 nm or less, preferably 5 nm or less in the wavelength range in which the windshield glass or projection image display member of the present invention exhibits reflection. .
Furthermore, when the projection image display member has a cholesteric liquid crystal layer as a selective reflection layer, all other layers have a small difference in refractive index from the average refractive index (in-plane average refractive index) of the cholesteric liquid crystal layer. It is preferable.
Examples of other layers include a support, an alignment layer, an adhesive layer, and a hard coat layer.

(Support)
The support can be used as a substrate when forming a retardation layer, or can also be used as a substrate when forming a selective reflection layer such as a cholesteric liquid crystal layer, which also serves as a retardation layer.
There are no restrictions on the material of the support. The support used for forming the cholesteric liquid crystal layer or the retardation layer may be a temporary support that is peeled off after forming the cholesteric liquid crystal layer or the polarization conversion layer, and therefore can be used for the completed projected image display. It may not be included in the component or windshield glass.
Examples of the support include polyesters such as polyethylene terephthalate (PET), polycarbonates, acrylic resins, epoxy resins, polyurethanes, polyamides, polyolefins, cellulose derivatives, and plastic films such as silicones. As the temporary support, in addition to the above-mentioned plastic film, glass may be used.
The thickness of the support is not limited, but may be about 5 to 1000 μm, preferably 10 to 250 μm, and more preferably 15 to 90 μm.
Further, when the support is included in a completed projection image display member or windshield glass rather than being peeled off as a temporary support, the support is preferably transparent in the visible light region. Furthermore, when used as a substrate for forming a retardation layer, it is preferable that the material has low birefringence.

(Orientation layer)
The projection image display member may include an alignment layer as a lower layer to which a liquid crystal composition is applied when forming a cholesteric liquid crystal layer or a retardation layer.
The alignment layer is formed by rubbing an organic compound such as a polymer (resin such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, polyetherimide, polyamide, and modified polyamide), obliquely depositing an inorganic compound, and having microgrooves. The formation of layers and the accumulation of organic compounds (such as ω-tricosanoic acid, dioctadecylmethylammonium chloride and methyl stearate) using the Langmuir-Blodgett method (LB membrane) can be applied. can. Furthermore, an alignment layer that exhibits an alignment function by applying an electric field, a magnetic field, or irradiation with light may be used.
In particular, it is preferable that the alignment layer made of an organic compound such as a polymer is subjected to a rubbing treatment and then a liquid crystal composition is applied to the rubbed surface. The rubbing treatment can be carried out by rubbing the surface of the polymer layer in a certain direction with paper, cloth, or the like.
The liquid crystal composition may be applied to the surface of the support without providing an alignment layer, or to the surface of the support that has been subjected to a rubbing treatment.
When forming a liquid crystal layer using a temporary support, the alignment layer does not need to be peeled off together with the temporary support to form a layer constituting a projection image display member.
The thickness of the alignment layer is preferably 0.01 to 5.0 μm, more preferably 0.05 to 2.0 μm.

(Hard coat layer)
The projection image display member of the present invention may include a hard coat layer on the surface in order to improve scratch resistance.

[Hard coat forming composition]
The hard coat layer is formed using a composition for forming a hard coat layer, for example.
The composition for forming a hard coat layer preferably contains a compound having three or more ethylenically unsaturated double bond groups in the molecule.
Examples of ethylenically unsaturated double bond groups include (meth)acryloyl groups, vinyl groups, and polymerizable functional groups such as styryl groups and allyl groups. Among them, (meth)acryloyl groups and C(O)OCH =CH ₂ is preferred, and (meth)acryloyl group is particularly preferred. By having an ethylenically unsaturated double bond group, high hardness can be maintained and heat and humidity resistance can also be imparted. Furthermore, by having three or more ethylenically unsaturated double bond groups in the molecule, higher hardness can be exhibited.

Examples of compounds having three or more ethylenically unsaturated double bond groups in the molecule include esters of polyhydric alcohols and (meth)acrylic acid, vinylbenzene and its derivatives, vinyl sulfone, and (meth)acrylamide. can be mentioned. Among them, from the viewpoint of hardness, compounds having three or more (meth)acryloyl groups are preferred, and examples include acrylate compounds that form highly hard cured products that are widely used in this industry. Such compounds include esters of polyhydric alcohols and (meth)acrylic acid {for example, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified tri(meth)acrylate, Methylolpropane tri(meth)acrylate, PO modified trimethylolpropane tri(meth)acrylate, EO modified phosphoric acid tri(meth)acrylate, trimethylolethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol Tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol hexa(meth)acrylate, 1,2,3-chlorohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate , and caprolactone-modified tris(acryloxyethyl)isocyanurate.
Specific examples of polyfunctional acrylate compounds having three or more (meth)acryloyl groups include KAYARAD DPHA, DPHA-2C, PET-30, TMPTA, TPA-320, and Nippon Kayaku Co., Ltd. TPA-330, RP-1040, T-1420, D-310, DPCA-20, DPCA-30, DPCA-60, GPO-303, V#400 manufactured by Osaka Organic Chemical Industry Co., Ltd., and , V#36095D and other esters of polyol and (meth)acrylic acid. In addition, Shiko UV-1400B, UV-1700B, UV-6300B, UV-7550B, UV-7600B, UV-7605B, UV-7610B, UV-7620EA, UV-7630B, UV- 7640B, UV-6630B, UV-7000B, UV-7510B, UV-7461TE, UV-3000B, UV-3200B, UV-3210EA, UV-3310EA, UV-3310B, UV- 3500BA, UV-3520TL, UV-3700B, UV-6100B, UV-6640B, UV-2000B, UV-2010B, UV-2250EA, and UV-2750B (manufactured by Nippon Gosei Kagaku Co., Ltd.) , UL-503LN (manufactured by Kyoeisha Chemical Co., Ltd.), Unidic 17-806, Unidic 17-813, Unidic V-4030 and Unidic V-4000BA (all manufactured by Dainippon Ink Chemical Co., Ltd.), EB-1290K, EB-220 , EB-5129, EB-1830 and EB-4358 (manufactured by Daicel UCB), Hicorp AU-2010 and AU-2020 (manufactured by Tokushiki), Aronix M-1960 (manufactured by Toagosei), Art Trifunctional or higher functional urethane acrylate compounds such as resin UN-3320HA, UN-3320HC, UN-3320HS, UN-904, HDP-4T, Aronix M-8100, M-8030, M-9050 (all manufactured by Toagosei Co., Ltd.) , and trifunctional or higher functional polyester compounds such as KBM-8307 (manufactured by Daicel Cytec) can also be suitably used.
Further, the compound having three or more ethylenically unsaturated double bond groups in the molecule may be composed of a single compound, or a plurality of compounds may be used in combination.

[Method for manufacturing hard coat layer]
The hard coat layer can be manufactured by applying the above composition for forming a hard coat layer onto a transparent support, drying and curing the composition to form a hard coat layer.

<Hard coat layer coating method>
The hard coat layer can be formed by the following coating method, but is not limited to this method. The hard coat layer can be applied using the following methods: dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, slide coating, extrusion coating (die coating). (see JP-A No. 2003-164788) and microgravure coating method, among which microgravure coating method and die coating method are preferred.

<Drying and curing conditions of hard coat layer>
In the present invention, preferred examples of drying and curing methods when forming a layer such as a hard coat layer by coating will be described below.
In the present invention, it is effective to cure by combining irradiation with ionizing radiation and heat treatment before, at the same time as, or after the irradiation.
Some manufacturing process patterns are shown below, but are not limited to these (the "-" below indicates that no heat treatment is performed).

Before irradiation → Simultaneously with irradiation → After irradiation (1) Heat treatment → Ionizing radiation curing → -
(2) Heat treatment → ionizing radiation hardening → heat treatment (3) - → ionizing radiation hardening → heat treatment

In addition, it is also preferable to carry out heat treatment at the same time as curing with ionizing radiation.

When forming the hard coat layer, as described above, it is preferable to perform heat treatment in combination with irradiation with ionizing radiation. The heat treatment is not particularly limited as long as it does not damage the support of the hard coat film and the constituent layers including the hard coat layer, but the temperature is preferably 25 to 150°C, more preferably 30 to 80°C.

The time required for the heat treatment varies depending on the molecular weight of the components used, interaction with other components, viscosity, etc., but is preferably 15 seconds to 1 hour, more preferably 20 seconds to 30 minutes, and even more preferably 30 seconds to 5 minutes.

The type of ionizing radiation is not particularly limited, and examples include X-rays, electron beams, ultraviolet rays, visible light, and infrared rays, but ultraviolet rays are widely used. For example, if the coating film is UV-curable, it is preferable to cure each layer by irradiating UV rays with an irradiance of 10 to 1000 mJ/cm ² using an UV lamp. At the time of irradiation, the above energy may be applied all at once, or it may be irradiated in parts. In particular, from the viewpoint of reducing in-plane performance variations of the coating film and improving curl, it is preferable to divide the irradiation into two or more times, and initially with a low irradiation dose of 150 mJ/cm ² or less. It is preferable to irradiate with ultraviolet light of 50 mJ/cm ^{2 or more, and then irradiate with ultraviolet light at a high dose of 50 mJ/cm 2} or more, and apply a higher dose in the later stage than in the initial stage.

(Adhesive layer)
The adhesive layer is provided at one or more locations, for example, between the support and the tilted retardation layer, between the cholesteric liquid crystal layers, between the cholesteric liquid crystal layer and the tilted retardation layer, and between the cholesteric liquid crystal layer and the polarization conversion layer. shall be established as necessary.

The adhesive layer may be formed from an adhesive (adhesive).
Adhesives are classified into hot melt type, thermosetting type, photocuring type, reaction curing type, and pressure sensitive adhesive type that does not require curing, and the materials for each type are acrylate type, urethane type, urethane acrylate type, and epoxy. Compounds such as epoxy acrylate series, polyolefin series, modified olefin series, polypropylene series, ethylene vinyl alcohol series, vinyl chloride series, chloroprene rubber series, cyanoacrylate series, polyamide series, polyimide series, polystyrene series, and polyvinyl butyral series. can be used. From the viewpoint of workability and productivity, a photocuring type is preferred as the curing method, and from the viewpoint of optical transparency and heat resistance, it is recommended to use acrylate, urethane acrylate, or epoxy acrylate materials as the material. preferable.

The adhesive layer may be formed using a highly transparent adhesive transfer tape (OCA (Optical Clear Adhesive) tape). As the highly transparent adhesive transfer tape, a commercially available product for use in image display devices, particularly a commercially available product for use on the surface of the image display portion of an image display device may be used. Examples of commercially available products include adhesive sheets manufactured by Panac Corporation (PD-S1, etc.), adhesive sheets of the MHM series manufactured by Nichiei Kako Co., Ltd., and the like.
The thickness of the adhesive layer is preferably 0.5 to 10 μm, more preferably 1.0 to 5.0 μm. Further, the thickness of the adhesive layer formed using the highly transparent adhesive transfer tape is preferably 4 to 50 μm, more preferably 5 to 30 μm. In order to reduce color unevenness of the projected image display member, it is preferable to provide the projection image display member with a uniform thickness.

Hereinafter, a windshield glass having a projection image display member and a head-up display system will be described.

<Windshield glass>
A windshield glass having a projection image display function can be provided using the projection image display member of the present invention.
Windshield glass refers to the window glass of general vehicles such as cars and trains, airplanes, ships, motorcycles, and play equipment. The windshield glass is preferably used as a windshield or windshield in the direction of travel of the vehicle.

The visible light transmittance of the windshield glass is preferably 70% or more, more preferably more than 70%, even more preferably 75% or more, and particularly preferably 80% or more. It is preferable that the above-mentioned visible light transmittance is satisfied at any position of the windshield glass, and it is particularly preferable that the projection image display section satisfies the above-mentioned visible light transmittance. As mentioned above, projection image display members have high visible light transmittance in the wavelength range with high visibility. It is possible to have a configuration that satisfies the ratio.

The windshield glass is not particularly limited, and is appropriately determined depending on the object on which the windshield glass is placed.
For example, it may be a planar shape or a three-dimensional shape having a curved surface such as a concave surface or a convex surface. In a windshield glass molded for a vehicle to which the windshield is applied, it is possible to specify the top side, the observer side, the driver side, and the visible side such as the inside of the vehicle during normal use. The windshield glass usually has a curved surface, and the concave side is the inside of the vehicle, that is, the incident side of the projected light in the head-up display system, that is, the viewing side of the image.

The windshield glass may have a uniform thickness or may have a non-uniform thickness in the projection image display section. For example, it may have a wedge-shaped cross-sectional shape like the vehicle glass described in Japanese Patent Publication No. 2011-505330, and the thickness of the projected image display portion may be non-uniform. In the case of a wedge-shaped cross-sectional shape, double images of projected light can be eliminated by overlapping reflections from the front and back surfaces of the glass.
The windshield glass is preferably laminated glass, and more preferably has an interlayer between two glass plates. It is more preferable that the windshield glass has a wedge-shaped cross-section due to the interlayer film.

[Projected image display section]
The projected image display member of the present invention is provided in a projected image display section of a windshield glass.
In other words, in the windshield glass and head-up display system of the present invention, the portion of the windshield glass where the projected image display member is attached serves as the projected image display section. Furthermore, when the projection image display member of the present invention has a selective reflection layer, it functions as a combiner for a head-up display system.
A projected image display section can be formed by providing a projected image displaying member on the outer surface of a glass plate of a windshield glass, or by providing it on an interlayer film of a windshield glass having a laminated glass structure as described later.
When the projected image display member is provided on the outer surface of the glass plate of the windshield glass, the projected image display member may be provided on the viewing side, that is, on the inside of the vehicle, when viewed from the glass plate, but it may be provided on the opposite side, that is, on the outside of the vehicle. However, it is preferable to provide it on the viewing side. Since the projected image display member has lower scratch resistance than a glass plate, it is also preferable to provide the projected image display member on an interlayer film in order to protect the projected image display member.

Note that the windshield glass and head-up display system of the present invention are not limited to those in which the projection image display member of the present invention acts as a combiner.
That is, in the case where the projected image display member does not have a selective reflection layer, the windshield glass and head-up display system of the present invention reflect the projected light by the windshield glass so that the driver (user) The configuration may also be such that the user is allowed to observe the projected image.
Further, in the windshield glass and head-up display system of the present invention, when the projected image display member does not have a selective reflection layer, the projected light can be reflected by the combiner originally incorporated in the head-up display system. Accordingly, the configuration may be such that the driver observes the projected light. When using a combiner that is originally incorporated into a head-up display system, the projected image display member of the present invention is attached to the combiner.

The projection image display section may be located on the entire surface of the windshield glass, or may be located on a portion of the entire area of the windshield glass, but it is preferably located on a portion of the entire area of the windshield glass.
If it is part of the windshield glass, the projected image display unit may be installed at any position on the windshield glass, but when used as a head-up display system, it must be located at a position that is easily visible to an observer such as a driver. Preferably, it is provided so that a virtual image is shown. For example, the position where the projected image display section is installed may be determined based on the relationship between the position of the driver's seat of the applicable vehicle and the position where the projector is installed.
The projected image display section may have a planar shape without a curved surface, or may have a curved surface, and has a concave or convex shape as a whole, and is capable of enlarging or contracting the projected light. It may be displayed.

[Laminated glass]
The windshield glass may have a laminated glass structure in which two glass plates are combined. The windshield glass may have a configuration in which a projection image display member is disposed between the first glass plate and the second glass plate. In this case, it is preferable that an intermediate film is provided between at least one of the first glass plate and the projected image display member and between the projected image display member and the second glass plate. In the windshield glass, for example, the first glass plate is disposed at a position farther from the visible side (outside the vehicle), and the second glass plate is disposed at a position closer to the visible side (inside the vehicle).
As the glass plates such as the first glass plate and the second glass plate, glass plates commonly used for windshield glass can be used. For example, a glass plate having a visible light transmittance of 80% or less, such as 73% and 76%, such as green glass with high heat shielding properties, may be used. Even when a glass plate with low visible light transmittance is used, by using a projection image display member, windshield glass that has a visible light transmittance of 70% or more even in the projection image display part can be used. can be created.

The thickness of the glass plate is not particularly limited, but may be about 0.5 to 5.0 mm, preferably 1.0 to 3.0 mm, and more preferably 2.0 to 2.3 mm. The materials or thicknesses of the first glass plate and the second glass plate may be the same or different.

A windshield glass having a laminated glass structure can be manufactured using a known laminated glass manufacturing method. Generally, after sandwiching an interlayer film for laminated glass between two glass plates, heat treatment and pressure treatment (treatment using rubber rollers, etc.) are repeated several times, and finally, an autoclave etc. is used. It can be manufactured by a method in which heat treatment is performed under pressurized conditions.

A windshield glass having a laminated glass structure including the above-mentioned projected image display member in the interlayer film may be formed by forming the projected image display member on the surface of the glass plate and then going through a normal laminated glass manufacturing process. Often, the laminated interlayer film for laminated glass containing the above-mentioned projection image display member may be used as an interlayer film, and the above-mentioned heat treatment and pressure treatment may be performed.
When the projected image display member is provided on the surface of a glass plate, the glass plate forming the projected image display member may be either the first glass plate or the second glass plate, but the glass plate forming the projected image display member may be either the first glass plate or the second glass plate. Preferably, it is provided on a glass plate. At this time, the projected image display member is bonded to a glass plate using an adhesive, for example.

(Interlayer film that does not include projected image display members)
When using an interlayer film (interlayer film sheet) that does not include the above-mentioned projection image display member, any known interlayer film may be used, and even an interlayer film having a wedge-shaped cross-section may be used. good.
As the intermediate film, for example, a resin film containing a resin selected from the group of polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer, and chlorine-containing resin can be used. The above-mentioned resin is preferably the main component of the interlayer film. Note that the term "main component" refers to a component that accounts for 50% by mass or more of the interlayer film.

Among the above-mentioned resins, polyvinyl butyral or ethylene-vinyl acetate copolymer is preferred, and polyvinyl butyral is more preferred. The resin is preferably a synthetic resin.
Polyvinyl butyral can be obtained by acetalizing polyvinyl alcohol with butyraldehyde. The preferable lower limit of the degree of acetalization of the above-mentioned polyvinyl butyral is 40%, the preferable upper limit is 85%, the more preferable lower limit is 60%, and the more preferable upper limit is 75%.

Polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate, and polyvinyl alcohol with a saponification degree of 80 to 99.8 mol% is generally used.
Moreover, the preferable lower limit of the degree of polymerization of the above-mentioned polyvinyl alcohol is 200, and the preferable upper limit is 3,000. When the polymerization degree of polyvinyl alcohol is 200 or more, the penetration resistance of the obtained laminated glass is unlikely to decrease, and when it is 3000 or less, the moldability of the resin film is good, and the rigidity of the resin film does not become too large. Good workability. A more preferable lower limit is 500, and a more preferable upper limit is 2,000.

(Interlayer film including projected image display member)
An interlayer film having a wedge-shaped cross-section may be used as the interlayer film of the laminated glass laminated glass including the projection image display member. The projected image display member can be formed by bonding it to the surface of the above-mentioned interlayer film. Alternatively, the projected image display member may be sandwiched between two interlayer films as described above. The two interlayer films may be the same or different, but are preferably the same.
Although a known bonding method can be used to bond the projection image display member and the interlayer film, it is preferable to use lamination processing. In order to prevent the laminate and the intermediate film from peeling off after processing, it is preferable to carry out the lamination treatment under a certain degree of heating and pressure conditions.
In order to perform stable lamination, the temperature of the surface of the interlayer film on the adhesion side is preferably 50 to 130°C, more preferably 70 to 100°C.
It is preferable to apply pressure during lamination. The pressurizing conditions are preferably less than 2.0 kg/cm ² (less than 196 kPa), more preferably 0.5 to 1.8 kg/cm ² (49 to 176 kPa), and more preferably 0.5 to 1.5 kg/cm ² (49 ~147 kPa) is more preferred.

Further, in a projection image display member including a support, the support may be peeled off at the same time as lamination, immediately after lamination, or immediately before lamination. That is, the laminated interlayer film obtained after lamination may not have a support.
An example of a method for manufacturing a laminated interlayer film for laminated glass is
(1) A first step of laminating a projection image display member on the surface of the first interlayer film to obtain a first laminate, and
(2) a second step of bonding a second intermediate film to the surface of the projection image display member in the first laminate opposite to the surface to which the first intermediate film is bonded; include.
In the first step, the projection image display member and the first interlayer film are bonded together, and the support is peeled off, and in the second step, the second interlayer film is attached to the surface from which the support has been peeled off. By the method for manufacturing a laminated interlayer film for laminated glass that involves bonding, it is possible to manufacture a laminated interlayer film for laminated glass that does not contain a support. laminated glass can be easily produced. In order to stably peel the support without damage, the temperature of the substrate when peeling the support from the projection image display member is preferably 40°C or higher, more preferably 40 to 60°C.

<Heads up display system>
Windshield glass can be used as a component of a head-up display system. Preferably, the head-up display system includes a projection display device. The projection image display device here refers to a projector which will be described later.

[projector]
A projector (imager) is a device that projects light or an image, and includes a device that projects a drawn image, and emits projection light that carries an image to be displayed (projected image). .
In the head-up display system, the projector may be arranged so that projection light carrying an image to be displayed is incident on the projection image display member in the windshield glass at an oblique incident angle.
In the head-up display system, the projector preferably includes a drawing device and displays an image (real image) drawn on a small intermediate image screen by reflecting it as a virtual image using a combiner.
It is preferable that the projector has a variable imaging distance of the virtual image, that is, a variable imaging position of the virtual image. As a projector capable of changing the imaging distance of a virtual image, a projector used in a known head-up display system can be used.
Methods for changing the imaging distance of a virtual image in a projector include, for example, a method of moving the image generation surface (screen) (see Japanese Patent Application Laid-Open No. 2017-21302), and a method of switching and using multiple optical paths with different optical path lengths. (Refer to International Publication No. 2015/190157), a method of changing the optical path length by inserting and/or moving a mirror, a method of changing the focal length using a lens set as an imaging lens, a method by moving the projector 22, a virtual image Examples include a method of switching and using a plurality of projectors with different imaging distances, and a method of using a variable focus lens (see International Publication No. 2010/116912).

Note that the projector may be one that can continuously change the imaging distance of the virtual image, or one that can change the imaging distance of the virtual image at two or more points.
Here, it is preferable that at least two of the virtual images of the light projected by the projector have different imaging distances by 1 m or more. Therefore, when the projector is capable of continuously changing the imaging distance of the virtual image, it is preferable that the imaging distance of the virtual image can be changed by 1 m or more. The use of such a projector is preferable because it can suitably cope with cases where the distance of the driver's line of sight differs greatly, such as when driving at normal speed on a general road and when driving at high speed on an expressway.

(drawing device)
The drawing device in the projector may itself be a device that displays an image, or may be a device that emits light that can draw an image. In the drawing device, light from a light source may be adjusted by a drawing method such as a light modulator, laser brightness modulation means, or light deflection means for drawing. The drawing device includes a light source, and further includes a light modulator, laser brightness modulation means, light deflection means for drawing, etc. depending on the drawing method.

(light source)
The light source is not particularly limited, and LEDs (light emitting diodes), organic light emitting diodes (OLEDs), discharge tubes, laser light sources, and the like can be used. Among these, LEDs and discharge tubes are preferred because they are suitable as light sources for drawing devices that emit linearly polarized light, and LEDs are particularly preferred. This is because LEDs have non-continuous emission wavelengths in the visible light range, so they are suitable for combination with combiners that use a cholesteric liquid crystal layer that exhibits selective reflection in a specific wavelength range, as will be described later.

(Drawing method)
The drawing method can be selected depending on the use of the light source and/or projector used, and is not particularly limited.
The drawing methods include a fluorescent display tube, an LCD (Liquid Crystal Display) method that uses liquid crystal, an LCOS (Liquid Crystal on Silicon) method, a DLP (registered trademark) (Digital Light Processing) method, and a scanning method that uses a laser. etc. The drawing method may be a method using a fluorescent display tube integrated with a light source. As the drawing method, an LCD method is preferable.

In the LCD method and the LCOS method, light of each color is modulated and multiplexed by a light modulator, and the light is emitted from a projection lens.
The DLP method is a display system using a DMD (Digital Micromirror Device), in which images are drawn by arranging micromirrors equal to the number of pixels, and light is emitted from a projection lens.

The scanning method is a method in which a light beam is scanned on a screen and a contrast is created using an afterimage of the eye. For example, the descriptions in JP-A-7-270711 and JP-A-2013-228674 can be referred to. In scanning methods that use lasers, brightness-modulated laser beams of each color, for example, red, green, and blue, are bundled into a single beam using a combining optical system or a condensing lens, and the beam is It is sufficient that the image is scanned by a deflecting means and drawn on an intermediate image screen which will be described later.
In the scanning method, for example, the brightness modulation of each color of laser light, such as red light, green light, and blue light, may be performed directly by changing the intensity of the light source, or may be performed by an external modulator. Examples of the light deflection means include a galvano mirror, a combination of a galvano mirror and a polygon mirror, and MEMS (Micro Electro Mechanical Systems), among which MEMS is preferred. Examples of the scanning method include a random scan method and a raster scan method, but the raster scan method is preferable. In the raster scan method, the laser beam can be driven, for example, with a resonant frequency in the horizontal direction and with a sawtooth wave in the vertical direction. Since the scanning method does not require a projection lens, it is easy to downsize the device.

The light emitted from the drawing device may be circularly polarized light, linearly polarized light, or natural light (non-polarized light).
The light emitted from the drawing device included in the head-up display system is preferably linearly polarized light. A drawing device whose drawing method is an LCD method or an LCOS method, and a drawing device using a laser light source essentially emit light as linearly polarized light.
If the output light is a drawing device that is linearly polarized light and the output light includes light of multiple wavelengths (colors), the polarization direction (transmission axis direction) of the polarized light of the multiple lights is the same or is different from each other. Preferably, they are orthogonal. It is known that some commercially available drawing devices do not have uniform polarization directions in the red, green, and blue wavelength ranges of emitted light (see Japanese Patent Laid-Open No. 2000-221449). Specifically, an example is known in which the polarization direction of green light is orthogonal to the polarization direction of red light and the polarization direction of blue light.

(Intermediate image screen)
As mentioned above, the rendering device may use an intermediate image screen. An "intermediate image screen" is a screen on which images are drawn. That is, in cases where the light emitted from the drawing device is not yet visible as an image, the drawing device uses this light to form a visible image on the intermediate image screen.
The image drawn on the intermediate image screen may be projected onto the combiner by light passing through the intermediate image screen, or may be projected onto the combiner by reflecting the intermediate image screen.

Examples of intermediate image screens include scattering films, microlens arrays, and rear projection screens.
When a plastic material is used as the intermediate image screen, if the intermediate image screen has birefringence, the polarization plane or light intensity of the polarized light incident on the intermediate image screen will be disturbed, and color unevenness will likely occur in the combiner. However, by using a retardation film having a predetermined retardation, this color unevenness problem can be reduced.
Preferably, the intermediate image screen has the function of spreading and transmitting incident light rays. This is because enlarged display of the projected image becomes possible. An example of such an intermediate image screen is a screen composed of a microlens array. Microarray lenses used in head-up displays are described, for example, in JP-A No. 2012-226303, JP-A No. 2010-145745, and Japanese Patent Application Publication No. 2007-523369.
The projector may include a reflecting mirror or the like that adjusts the optical path of the projected light formed by the drawing device.

As described above, the projected image display member of the present invention does not have a selective reflection layer, and the projected light from the projector is reflected by the windshield glass, thereby allowing the driver to observe the image in a head-up display system. It is also available.
Regarding a head-up display system in which an image is observed by reflecting the projected light from a projector using a windshield glass, Japanese Patent Application Publication No. 2-141720, Japanese Patent Application Publication No. 10-96874, Japanese Patent Application Publication No. 2003-98470, Reference may be made to US Pat. No. 5,013,134, Japanese Patent Application Publication No. 2006-512622, and the like.

The windshield glass of the present invention is particularly useful for head-up display systems used in combination with projectors that use lasers, LEDs, OLEDs (organic light-emitting diodes), etc. as light sources whose emission wavelengths are not continuous in the visible light region. be. This is because the center wavelength of selective reflection of the cholesteric liquid crystal layer can be adjusted according to each emission wavelength. Further, it can also be used for projecting a display such as an LCD (liquid crystal display) in which display light is polarized.

[Projection light (incident light)]
The incident light is preferably incident at an oblique angle of incidence of 45 to 70 degrees with respect to the normal line of the projection image display member. The Brewster angle at the interface between glass with a refractive index of about 1.51 and air with a refractive index of 1 is about 56 degrees, and by making P-polarized light incident within the above-mentioned angle range, the incident light for projection image display can be With respect to the selective reflection layer, there is less light reflected from the surface of the windshield glass on the viewing side, making it possible to display images with less influence of double images. It is also preferred that the angle mentioned above is between 50 and 65 degrees. At this time, the projected light can be observed on the incident side of the projected light (inside the vehicle) at an angle of 45 to 70 degrees with respect to the normal to the selective reflection layer or windshield glass on the side opposite to the incident light. It is preferable to have a configuration that allows the rotation to be performed at an angle of 50 to 68 degrees.
In order to strengthen the reflected light on the windshield glass surface at the above-mentioned angle, it is preferable to make S-polarized light incident. Here, since a double image is generated by light reflected from the front and back surfaces of the windshield glass, it is preferable to use a windshield glass having a wedge-shaped cross section.

The incident light may be incident from any direction, such as the top, bottom, left, or right of the windshield glass, and may be determined in accordance with the viewing direction. For example, a configuration in which the light is incident from below at an oblique angle of incidence as described above during use is preferable.

As described above, when displaying a projected image on a head-up display used in conjunction with wedge-shaped glass, the projected light is preferably S-polarized light that vibrates in a direction perpendicular to the plane of incidence. If the emitted light from the projector is not linearly polarized, it may be made into S-polarized light by placing a linearly polarizing film on the emitted light side of the projector, and the light will be S-polarized along the optical path from the projector to the windshield glass. Good too.
As mentioned above, for projectors where the polarization direction of the emitted light is not uniform in the red, green, and blue wavelength ranges, the polarization direction is adjusted wavelength-selectively, and all color wavelength ranges are treated as S-polarized light. It is preferable to make it incident.

Next, the head-up display system will be described in more detail with reference to FIGS. 3 and 4.
FIG. 3 is a schematic diagram showing an example of a head-up display having a projected image display member according to an embodiment of the present invention, and FIG. 4 is a partially enlarged schematic diagram of a windshield glass having a projected image display member according to the present invention. It is.
The head-up display system 20 includes a projector 22 and a windshield glass 24, and is used, for example, in a vehicle such as a passenger car. Note that each component of the head-up display system 20 is as already described. Hereinafter, the head-up display system 20 will also be referred to as HUD 20.

In the HUD 20, the windshield glass 24 includes a first glass plate 28, a second glass plate 30, a projected image display member 10, an intermediate film 36, and an adhesive layer 38, as conceptually shown in FIG. has. In the windshield glass 24, the first glass plate 28, the second glass plate 30, and the intermediate film 36 constitute a windshield glass main body in the windshield glass of the present invention. The projected image display member 10 is adhered to the windshield glass body by an adhesive layer 38.
In the illustrated HUD 20, the second glass plate 30 is located on the inside of the vehicle. In a preferred embodiment of the windshield glass 24 (HUD 20), the projected image display member 10 is attached to the inside of the vehicle, that is, on the incident side of the projected light. Typically, the windshield glass body has a concave surface on the inside of the vehicle. That is, in the windshield glass of the present invention, preferably, the projection image display member 10 is attached to the concave surface of the windshield glass body.
However, the windshield glass of the present invention is not limited to a configuration in which the projected image display member 10 is provided on the outer surface of the windshield glass body, that is, the surface on the inside or outside of the vehicle, and the first glass plate 28 and the second glass plate As described above, the projection image display member 10 may be provided between the projection image display member 30 and the projection image display member 10.

As described above, the projection image display member 10 includes the polarization conversion layer 11 , the selective reflection layer 12 , the inclined retardation layer 14 , and the support 15 .
In the HUD 20, the projected image display member 10 is arranged so that the vertical direction Y of the windshield glass 24 and the axis H of the inclined retardation layer 14 shown in FIG. 2 are aligned.
When mounted on a vehicle, the vertical direction (vertical direction) Y of the windshield glass 24 is a direction in which the ground side of the vehicle, etc. on which the windshield glass 24 is placed is the lower side, and the opposite side of the lower side is the upper side. It is. Note that when the windshield glass 24 is placed on a vehicle or the like, it may be placed at an angle due to structure or design reasons, but in this case, the vertical direction Y will be The direction will be along.

The projector 22 is as described above.
As the projector 22, any known projector used in a HUD can be used as long as it carries an image to be displayed, can emit projection light, and has a variable imaging distance of the virtual image, that is, a variable imaging position of the virtual image. It is. The projection light emitted by the projector 22 may be S-polarized light, P-polarized light, circularly polarized light, or non-polarized light, but S-polarized light is preferable.

In the HUD 20, the projector 22 irradiates the windshield glass 24 (second glass plate 30) with S-polarized projection light, as a preferable embodiment.

The windshield glass 24 is a so-called laminated glass, and has an interlayer film 36 between the first glass plate 28 and the second glass plate 30, and a projected image on the projection light incident side of the second glass plate 30. It has a display member 10 and an adhesive layer 38.
As described above, the projection image display member 10 includes the polarization conversion layer 11 , the selective reflection layer 12 , the inclined retardation layer 14 , and the support 15 .
In the illustrated example, the projected image display member 10 is bonded to the second glass plate 30 (windshield glass body) with the adhesive layer 38, with the polarization conversion layer 11 facing the second glass plate 30. Therefore, the projected light from the projector 22, which will be described later, enters the projected image display member 10 from the support 15 side.
The selective reflection layer 12 is the main body of the projection image display member 10, and like a normal half mirror, it reflects part of the incident light and transmits part of it.

The first glass plate 28 and the second glass plate 30 are both known glasses (glass plates) used for windshields of vehicles and the like. Therefore, the forming material, thickness, shape, etc. may be similar to glass used in known windshields. Although both the first glass plate 28 and the second glass plate 30 shown in FIG. 4 are flat, they are not limited to this, and may have a partially curved surface or may have a curved surface entirely.

The interlayer film 36 prevents the glass from penetrating into the vehicle interior and scattering in the event of an accident, and also serves to bond the first glass plate 28 and the second glass plate 30 together. As the interlayer film 36, a known interlayer film and adhesive layer used for laminated glass windshields can be used. Examples of materials for forming the intermediate film 36 include polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer, chlorine-containing resin, and polyurethane.
Further, there is no limit to the thickness of the interlayer film 36, and the thickness may be set depending on the forming material, etc., in the same manner as the interlayer film of known windshield glass.

The adhesive layer 38 is a layer made of a coating type adhesive. The projected image display member 10 is attached to the second glass plate 30 with an adhesive layer 38.
There are no restrictions on the adhesive layer 38, and any known material can be used as long as it can ensure the transparency required for the windshield glass 24 and can adhere the projection image display member 10 and the glass with the necessary adhesion force. Various types of paint-on adhesives are available. As the adhesive layer 38, the same material as the intermediate film 36 may be used, or as an example, polyvinyl butyral (PVB) may be used. In addition to this, an acrylate adhesive or the like can also be used for the adhesive layer 38. Further, the adhesive layer 38 may be the same as the adhesive layer described above, as shown below.

The adhesive layer 38 may be formed from an adhesive similar to the adhesive layer described above.
Adhesives are classified into hot melt type, thermosetting type, photocuring type, reaction curing type, and pressure sensitive adhesive type that does not require curing, and the materials for each are acrylate type, urethane type, urethane acrylate type, and epoxy. Compounds such as epoxy acrylate series, polyolefin series, modified olefin series, polypropylene series, ethylene vinyl alcohol series, vinyl chloride series, chloroprene rubber series, cyanoacrylate series, polyamide series, polyimide series, polystyrene series, and polyvinyl butyral series. can be used. From the viewpoint of workability and productivity, a photocuring type is preferred as the curing method, and from the viewpoint of optical transparency and heat resistance, it is recommended to use acrylate, urethane acrylate, or epoxy acrylate materials as the material. preferable.

The adhesive layer 38 may be formed using a highly transparent adhesive transfer tape (OCA tape). As the highly transparent adhesive transfer tape, a commercially available product for use in image display devices, particularly a commercially available product for use on the surface of the image display portion of an image display device may be used. Examples of commercially available products include adhesive sheets manufactured by Panac (PD-S1, etc.) and MHM series adhesive sheets manufactured by Nichiei Kako.

There is also no limit to the thickness of the adhesive layer 38. Therefore, depending on the material for forming the adhesive layer 38, a thickness that provides sufficient adhesion strength may be appropriately set.
Here, if the adhesive layer 38 is too thick, the projected image display member 10 may not be able to be adhered to the second glass plate 30 while maintaining sufficient flatness, which will be described later. Considering this point, the thickness of the adhesive layer 38 is preferably 0.1 to 800 μm, more preferably 0.5 to 400 μm.

Note that the windshield glass 24 is provided with an adhesive layer 38 on the projection light incident side of the second glass plate 30, and the projected image display member 10 is attached thereto, but the present invention is not limited thereto. That is, the adhesive layer 38 is provided on the opposite side of the projection light incident side of the second glass plate 30, the projected image display member 10 is attached, and an intermediate layer is formed between the projected image display member 10 and the first glass plate 28. A configuration in which a membrane 36 is provided may also be used.
Alternatively, the windshield glass 24 may have a structure in which the interlayer film 36 is not provided, and an adhesive layer 38 may be provided on a wedge-shaped glass plate, and the projection image display member 10 may be adhered thereto.
The adhesive layer 38 may be used for adhering the projected image display member 10 and the first glass plate 28 and for adhering the projected image display member 10 and the second glass plate 30.

As shown in FIG. 3, in the HUD 20, an image observer, that is, a driver D, sees the light projected by the projector 22, which is projected by the projector 22 and reflected by the projected image display member 10 (its selective reflection layer 12). Observing virtual images.
In a typical HUD, projected light from a projector is reflected by a windshield glass, and the reflected light is observed. Here, a typical windshield is laminated glass and has two pieces of glass, an inner surface and an outer surface. Therefore, in the HUD, there is a problem in that the driver sees a double image due to the reflected light from the two pieces of glass.
In order to cope with this, in normal HUDs, the cross-sectional shape of the windshield (intermediate film) is made wedge-shaped so that the reflection from the inner glass and the reflection from the outer glass overlap, so that double images are not visible. That's what I do.

In the example shown in FIG. 3, as an example, an interlayer film 36 is provided between the first glass plate 28 and the second glass plate 30, and the projected image display member 10 is directly attached to the adhesive layer 38 made of a coated adhesive. The flatness of the projected image display member 10 is ensured by attaching it to the first glass plate 28 .

Hereinafter, the present invention will be explained in more detail by explaining the operation of the HUD 20 shown in FIG. 3.

In a preferred embodiment of the HUD 20, the projector 22 emits S-polarized projection light.
The projection light emitted by the projector 22 passes through the support 15 and enters the inclined retardation layer 14 from the support 15 side. The inclined retardation layer 14 has a rod-shaped liquid crystal compound oriented obliquely with respect to the surface of the inclined retardation layer 14 . Further, the direction of inclination of the rod-shaped liquid crystal compound is the same direction as the traveling direction of the projected light from the projector 22.
Therefore, even if the projected light emitted by the projector 22 enters the inclined retardation layer 14, it is not subjected to any optical action and is transmitted as S-polarized light. Alternatively, even if the projected light emitted by the projector 22 enters the inclined retardation layer 14, the effect of the retardation layer from the inclined retardation layer 14 is small, and the projected light is transmitted while containing many S-polarized light components. .

The projected light transmitted through the inclined retardation layer 14 is reflected by the selective reflection layer 12 (first selective reflection layer 12G and second selective reflection layer 12R).
The selective reflection layer 12 is, as a preferable example, a cholesteric liquid crystal layer. Therefore, the S-polarized projected light reflected by the selective reflection layer 12 becomes elliptically polarized light with a large S-polarized component.

The projection light reflected by the selective reflection layer 12 enters the inclined retardation layer 14 again. The projection light reflected by the selective reflection layer 12 enters the inclined retardation layer 14 from the side of the selective reflection layer 12 that is opposite to the projection light emitted by the projector 22.
Therefore, the direction of inclination of the rod-shaped liquid crystal compound of the inclined retardation layer 14 is opposite to the direction of propagation of light. Therefore, the inclined retardation layer 14 acts as a retardation layer for the projection light that enters the inclined retardation layer 14 from the selective reflection layer 12 side.
As a result, the projected light of elliptically polarized light with a large amount of S-polarized light component reflected by the selective reflection layer 12 is transmitted through the inclined retardation layer 14, and its phase changes to become elliptically polarized light with a large amount of P-polarized light component.

The projected light, which is elliptically polarized light from the P-polarized light that has passed through the inclined retardation layer 14, passes through the support 15 and is observed by the driver D.
Here, the projected light observed by the driver D is elliptically polarized light with a large P-polarized component, that is, it contains a large amount of P-polarized light. Therefore, even if the driver D wears polarized sunglasses that block S-polarized light, it is possible to observe the projected image using P-polarized light, which is included in a large amount in the projected light.

As described above, the glare caused by light reflected by puddles, bonnets, etc., which driver D finds dazzling, is often S-polarized light. Therefore, polarized sunglasses are usually designed to block S-polarized light.
On the other hand, in a HUD that allows the driver D to observe the projected light by reflecting the projected light on the windshield glass, the projector 22 projects S-polarized light in order to increase the reflectance of the image by the windshield glass. Often irradiated with light. In this case, the projected light reflected by the windshield glass is also S-polarized light.
Therefore, when driver D wears polarized sunglasses, the projected light is blocked by the polarized sunglasses, and driver D cannot observe the image on the HUD.

In contrast, according to the projection image display member, windshield glass, and HUD of the present invention, even if the HUD mounted on the vehicle is configured to reflect S-polarized projected light on the windshield glass, the projection image display member of the present invention can be used. By simply adhering the image display member to the inside surface of the windshield glass, for example, it becomes possible to irradiate the projection light of P-polarized light.
That is, according to the present invention, even if a vehicle-mounted HUD has a configuration in which S-polarized projected light is reflected by the windshield glass, the projected image display member of the present invention can be used, for example, on the inside surface of the windshield glass. By simply adhering to the polarized sunglasses, even if the driver D wears polarized sunglasses, the image on the HUD can be observed, thereby improving the suitability of the polarized sunglasses.

In addition, in the projected light from the projector 22, a component that is reflected on the surface of the projected image display member 10 (support body 15), a component that is transmitted through the projected image display member 10, and a component that is reflected by the surface of the projected image display member 10 (support body 15), a component that is reflected by the surface of the projected image display member 10, and a component that is transmitted through the projected image display member 10, A component reflected by the surface of the first glass plate 28 (glass plate on the outside of the vehicle) is also generated.
Since the component reflected on the surface of the projected image display member 10 is S-polarized light, if the driver D wears polarized sunglasses, the light will be blocked. Even when driver D is not wearing polarized sunglasses, each layer constituting the projected image display member 10 is very thin, so there is a possibility that the components reflected by the selective reflection layer 12 and the second glass plate 30 will be misaligned. is small, and the observation of double images can be suppressed.
In a preferred embodiment, the windshield glass is wedge-shaped glass. Therefore, there is no misalignment between the component reflected on the surface of the second glass plate 30 and the component reflected on the surface of the first glass plate 28, so that double images can be suppressed from being observed.

As described above, the glare caused by light reflected by puddles, bonnets, etc., which driver D finds dazzling, is often S-polarized light. Therefore, polarized sunglasses are usually designed to block S-polarized light.
The illustrated projection image display member 10 has a polarization conversion layer 11 as a preferred embodiment. Since the projected image display member 10 has the polarization conversion layer 11, it becomes possible to suitably block the glare of S-polarized light that enters from outside the vehicle with polarized sunglasses. That is, by having the polarization conversion layer 11 in the projection image display member 10, polarized sunglasses can be suitably adapted to external light entering from outside the vehicle.

The glaring S-polarized light entering from outside the vehicle first passes through the first glass plate 28, the intermediate film 36, and the second glass plate, and enters the polarization conversion layer 11. The S-polarized light that has entered and passed through the polarization conversion layer 11 is converted into elliptically polarized light with a rotation direction corresponding to the S-polarized light due to the helical structure of the liquid crystal compound in the polarization conversion layer 11 or the phase difference of the polarization conversion layer 11 .
The elliptically polarized light that has passed through the polarization conversion layer 11 then passes through the selective reflection layer 12, which is a cholesteric liquid crystal layer, and is converted into circularly polarized light with a rotation direction corresponding to the S-polarized light.
The circularly polarized light that has passed through the selective reflection layer 12 is incident on the inclined retardation layer 14 . As described above, the inclined retardation layer 14 acts as a retardation layer for light incident from the selective reflection layer 12 side. Therefore, the circularly polarized light in the rotation direction corresponding to the S-polarized light passes through the inclined retardation layer 14 and is converted into S-polarized light.
The glaring S-polarized light incident from outside the vehicle is thus returned to S-polarized light, passes through the support 15, and reaches the driver D, but is blocked by the polarized sunglasses.
That is, by having the polarization conversion layer 11, the projection image display member 10 of the present invention compensates for changes in the polarization of external light due to the inclined retardation layer 14 and the selective reflection layer 12, and reduces glare incident from outside the vehicle. S-polarized light can pass through as S-polarized light, making it possible to block the light with polarized sunglasses.

The illustrated projection image display member 10 has a selective reflection layer 12 as a preferred embodiment. However, the projection image display member of the present invention does not need to have the selective reflection layer 12.
Even if the projection image display member of the present invention does not have this selective reflection layer 12, the S-polarized light irradiated as the projected light can be used as the projected light containing the P-polarized component, so that the user can wear polarized sunglasses. images can be observed. However, it is preferable that the projection image display member of the present invention has the selective reflection layer 12 in that the image observed by the driver D can have high brightness.

Even in a projection image display member that does not have the selective reflection layer 12 , the S-polarized projection light emitted from the projector 22 similarly passes through the support 15 and enters the inclined retardation layer 14 .
As described above, the inclined retardation layer 14 does not perform any optical action on the S-polarized projected light incident from the support 15 side. Therefore, the S-polarized projected light passes through the inclined retardation layer 14 and enters the windshield glass body.
The S-polarized projected light incident on the windshield glass body is reflected by the second glass plate 30 and the first glass plate 28, and enters the inclined retardation layer 14 again as S-polarized light.

As in the previous example, the inclined retardation layer 14 acts as a retardation layer for light incident from the second glass plate 30 side. Therefore, the S-polarized projected light that is reflected by the second glass plate 30 and the like and re-enters the inclined retardation layer 14 has its phase changed by the inclined retardation layer 14, and becomes P-polarized light in a direction including the P-polarized light component. It is converted into linearly polarized light, elliptically polarized light, or circularly polarized light. Elliptically polarized light and circularly polarized light include a P-polarized component.
Therefore, even if the driver D is wearing polarized sunglasses, the P-polarized light component passes through the polarized sunglasses, so the driver D can observe the image on the HUD.
Note that this effect is the same when the selective reflection layer is a linearly polarized light reflection layer and when it is a non-polarized light reflection layer.

The projection image display member according to the first aspect of the present invention described above has an inclined retardation layer in which the rod-shaped liquid crystal compound is oriented obliquely with respect to the surface of the retardation layer.
On the other hand, the projection image display member according to the second aspect of the present invention has a retardation layer having a front retardation of 100 to 350 nm instead of the inclined retardation layer.
The projection image display member according to the second aspect of the present invention is the projection image display member according to the first aspect described above, except that it has a retardation layer having a front retardation of 100 to 350 nm instead of the inclined retardation layer. It is similar to Therefore, the following explanation will mainly focus on the different parts.

In the projection image display member according to the second aspect of the present invention having a retardation layer having a front retardation of 100 to 350 nm instead of the inclined retardation layer, the retardation layer is used to prevent the S-polarized projection light emitted by the projector 22 from being reflected. The phase difference is changed to convert the light into P-polarized light, linearly polarized light in a direction including a P-polarized light component, elliptically polarized light, or circularly polarized light.
Therefore, even if the driver D wears polarized sunglasses that block S-polarized light, the P-polarized light component allows the driver to observe the image on the HUD, thereby improving the suitability of the polarized sunglasses.

The projection image display member of the second aspect of the present invention having a retardation layer with a front retardation of 100 to 350 nm is preferably used particularly when the projection light emitted by the projector 22 is circularly polarized light.
Circularly polarized light includes a P-polarized component. Therefore, in the projection image display member according to the second aspect of the present invention, suitability for polarized sunglasses is improved, and when driver D wears polarized sunglasses that block S-polarized light, the driver D can more preferably use the HUD. images can be observed.

In the projection image display member according to the second aspect of the present invention, the front retardation of the retardation layer is 100 to 350 nm.
If the front retardation of the retardation layer is 100 nm or less, disadvantages arise in that the amount of change in polarized light passing through the retardation layer is insufficient.
On the other hand, if the front retardation of the retardation layer exceeds 350 nm, there will be problems in that the retardation layer becomes too thick and orientation defects are likely to occur.

In the projection image display member according to the second aspect of the present invention, the front retardation of the retardation layer is determined by the front retardation of the projected light of P-polarized light depending on the incident angle of the projected light, the direction of the slow axis of the retardation layer, etc. Alternatively, the wavelength may be appropriately set within the range of 100 to 350 nm so as to obtain projection light containing a P-polarized component.
In the projection image display member according to the second aspect of the present invention, the front retardation of the retardation layer is preferably 105 to 320 nm, more preferably 110 to 300 nm.

In the projection image display member according to the second aspect of the present invention, the retardation layer having a front retardation of 100 to 350 nm may also serve as a retardation layer that is a polarization conversion layer.

Like the projection image display member of the first aspect described above, the projection image display member of the second aspect of the present invention also preferably has a selective reflection layer. Further, the selective reflection layer may be a polarized light reflective layer or a non-polarized light reflective layer, but a polarized light reflective layer is preferable.
Further, the polarized light reflective layer may be a linearly polarized light reflective layer or a circularly polarized light reflective layer.

Here, in the projection image display member according to the second aspect of the present invention, when the selective reflection layer is a linearly polarized light reflection layer, when the projection image display member is provided on the windshield glass and mounted on a vehicle, , the direction of the refractive index anisotropy of the linearly polarized light reflective layer is 10 to 80 degrees clockwise when viewed from the projection image display side, when the above-mentioned vertical direction Y (vertical direction) is set to 0 degrees, or , preferably inclined at an angle of 100 to 170 degrees.
By having such a configuration, favorable results can be obtained in that more P-polarized light can be reflected when S-polarized light is projected.
The direction of the refractive index anisotropy of the linearly polarized light reflective layer is more preferably 30 to 60 degrees clockwise when viewed from the projection image display side, or more preferably 120 to 150 degrees.

The present invention is basically constructed as described above.
Although the projected image display member, windshield glass, and head-up display system of the present invention have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention. Of course, improvements or changes may be made.

The features of the present invention will be explained in more detail with reference to Examples below. The materials, reagents, amounts and ratios of substances shown in the following examples, operations, etc. can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following examples.
Examples 1 to 69 and Comparative Example 1 were manufactured with the configurations shown in Table 1 (Tables 1-1 to 1-4), and the retardation layer, selective reflection layer, and polarization conversion layer were prepared using the methods described below. It was created by.
The configurations in Table 1 are listed from the left in the order in which the projection light is incident. Comparative Example 1 has a structure consisting of only wedge-shaped glass, and does not include a retardation layer, a selective reflection layer, or a polarization conversion layer.
If the retardation layer has a rod-like liquid crystal compound tilted with respect to the support, that is, the surface of the retardation layer, the angle of inclination is described.
There are three types of selective reflection layers: a circularly polarized light reflective layer made of cholesteric liquid crystal, a linearly polarized light reflective layer made of an optically anisotropic dielectric multilayer, and a non-polarized light reflective layer made of an isotropic dielectric multilayer. .
There are two types of polarization conversion layers: one consisting of a helically aligned structure of rod-like liquid crystal compounds, and a retardation layer.

<Preparation of coating liquid>
(Coating liquid 1 and 2 for forming cholesteric liquid crystal layer)
Regarding coating liquid 1 for forming a cholesteric liquid crystal layer that forms a cholesteric liquid crystal layer that reflects light within a wavelength range of 580 nm, and coating liquid 2 for forming a cholesteric liquid crystal layer that forms a cholesteric liquid crystal layer that reflects light within a wavelength range of 700 nm. The following components were mixed to prepare a coating liquid for forming a cholesteric liquid crystal layer having the following composition.
・Mixture 1 100 parts by mass ・Fluorine-based horizontal alignment agent 1 (orientation control agent 1 below) 0.05 parts by mass ・Fluorine-based horizontal alignment agent 2 (orientation control agent 2 below) 0.02 parts by mass ・Right-handed chiral Agent LC756 (manufactured by BASF)
Polymerization initiator IRGACURE OXE01 (manufactured by BASF) adjusted according to the target reflection wavelength
1.0 parts by mass/solvent (methyl ethyl ketone) Amount for solute concentration to be 20% by mass

Coating liquid 1 for forming a cholesteric liquid crystal layer and coating liquid 2 for forming a cholesteric liquid crystal layer were prepared by adjusting the prescribed amount of the right-handed chiral agent LC756 having the above-mentioned coating liquid composition.
Using Coating Liquid 1 for Forming a Cholesteric Liquid Crystal Layer or Coating Liquid 2 for Forming a Cholesteric Liquid Crystal Layer, a film with a thickness of 3 μm is coated on a temporary support in the same manner as in the production of the projection image display member (half mirror) shown below. We fabricated a single-layer cholesteric liquid crystal layer and confirmed its visible light reflection characteristics. As a result, all of the produced cholesteric liquid crystal layers were right-handed circularly polarized light reflecting layers, and the center reflection wavelength was 580 nm for coating liquid 1 and 700 nm for coating liquid 2.

(Coating liquid for forming retardation layer)
The following components were mixed to prepare a coating liquid for forming a retardation layer having the following composition.
・Mixture 1 100 parts by mass ・Fluorinated horizontal alignment agent 1 (alignment control agent 1) 0.05 parts by mass ・Fluorinated horizontal alignment agent 2 (alignment control agent 2) 0.01 parts by mass ・Polymerization initiator IRGACURE OXE01 (BASF company)
1.0 parts by mass/solvent (methyl ethyl ketone) Amount for solute concentration to be 20% by mass

(Coating liquid for forming inclined retardation layer)
The following components were mixed to prepare a coating liquid for forming a retardation layer having the following composition. The amount of the alignment control agent 3 was adjusted to around 1.5 parts by mass so that the inclination angle of the retardation layer shown in Table 1 would be the desired value.
・Mixture 1 100 parts by mass ・Fluorine-based horizontal alignment agent 1 (alignment control agent 1) 0.05 parts by mass ・Fluorine-based horizontal alignment agent 2 (alignment control agent 2) 0.01 part by mass ・Vertical alignment agent 1 (the following alignment Control agent 3) Adjust to 1.5 parts by mass / Polymerization initiator IRGACURE OXE01 (manufactured by BASF)
1.0 parts by mass/solvent (methyl ethyl ketone) Amount for solute concentration to be 20% by mass

Orientation control agent 3

(Coating liquid for forming polarization conversion layer)
The following components were mixed to prepare a coating liquid for forming a polarization conversion layer having the following composition.
・Mixture 1 100 parts by mass ・Fluorine-based horizontal alignment agent 1 (orientation control agent 1) 0.05 parts by mass ・Fluorine-based horizontal alignment agent 2 (orientation control agent 2) 0.02 parts by mass ・Right-handed chiral agent LC756 (manufactured by BASF)
Polymerization initiator IRGACURE OXE01 (manufactured by BASF) Adjust according to the reflection wavelength that matches the target pitch number and film thickness
1.0 parts by mass/solvent (methyl ethyl ketone) Amount for solute concentration to be 20% by mass

Adjust the prescription amount of the right-handed chiral agent LC756 with the above-mentioned coating liquid composition, and use the coating liquid for forming a polarization conversion layer so that the desired selective reflection center wavelength λ is obtained when it is considered as a cholesteric liquid crystal layer. Prepared.
Since the film thickness d of the helical structure can be expressed by the relational expression of pitch (reflection center wavelength λ/in-plane average refractive index n) x number of pitches, the film thickness and number of pitches were specified, and λ (wavelength) was determined. The pitch number is the twist angle (pitch number x 360 degrees) obtained by creating a single layer cholesteric liquid crystal layer of the desired thickness on a temporary support and fitting the measured value of AxoScan (manufactured by Axometrix). I asked for it from
Table 1 shows the combinations of the pitch number, film thickness, and λ of the polarization conversion layer, which are the targets of the adjusted polarization conversion layer forming coating liquid.

<Saponification of cellulose acylate film>
A 40 μm cellulose acylate film obtained by the same production method as Example 20 of International Publication No. 2014/112575 was passed through a dielectric heating roll at a temperature of 60°C, and the film surface temperature was raised to 40°C. An alkaline solution having the composition shown below was applied to one side of the film at a coating amount of 14 mL/m ² using a bar coater, and the film was placed under a steam-type far-infrared heater (manufactured by Noritake Company Limited) heated to 110°C. It was allowed to stay for 10 seconds.
Next, 3 mL/m ² of pure water was applied using the same bar coater.
Next, washing with water using a fountain coater and draining using an air knife were repeated three times, and then the film was dried by staying in a drying zone at 70° C. for 5 seconds to produce a saponified cellulose acylate film 1.
When the in-plane retardation of the cellulose acylate film 1 was measured using AxoScan, it was 1 nm.

(alkaline solution)
・Potassium hydroxide 4.7 parts by mass ・Water 15.7 parts by mass ・Isopropanol 64.8 parts by mass ・Surfactant (C ₁₆ H ₃₃ O(CH ₂ CH ₂ O) ₁₀ H) 1.0 parts by mass ・Propylene Glycol 14.9 parts by mass

<Formation of alignment film>
On the saponified surface of the saponified cellulose acylate film 1 (transparent support) obtained above, a coating solution for forming an alignment film having the composition shown below was coated at 24 mL/m ² with a wire bar coater, and heated at 100°C. It was dried with hot air for 120 seconds.

(Coating liquid for forming alignment film)
・Modified polyvinyl alcohol shown below 28 parts by mass ・Citric acid ester (AS3, manufactured by Sankyo Kagaku Co., Ltd.) 1.2 parts by mass ・Photoinitiator (Irgacure 2959, manufactured by BASF) 0.84 parts by mass ・Glutaraldehyde 2.8 Parts by mass/Water 699 parts by mass/Methanol 226 parts by mass

(Modified polyvinyl alcohol)

<Preparation of silica particle dispersion>
AEROSIL RX300 (manufactured by Nippon Aerosil Co., Ltd.) as inorganic fine particles preferably used in the hard coat layer in the present invention was added to MiBK (methyl isobutyl ketone) so that the solid content concentration was 5% by mass, and stirred with a magnetic stirrer for 30 minutes. The mixture was stirred for a minute. Thereafter, ultrasonic dispersion was performed for 10 minutes using an ultrasonic dispersion machine (manufactured by SMT Corporation, Ultrasonic Homogenizer UH-600S) to prepare a silica particle dispersion.
A portion of the resulting dispersion was taken for measurement of the average secondary particle diameter, and the average secondary particle diameter of the silica particles in the dispersion was measured using Microtrac MT3000 (manufactured by Microtrac Bell Co., Ltd.). It was 190 nm.

<Preparation of hard coat layer coating solution>
Each component was mixed to have the following composition to prepare a hard coat layer coating solution having a solid content concentration of about 51% by mass.
(Hard coat layer coating liquid)
・Dipentaerythritol polyacrylate: A-9550W
(Manufactured by Shin Nakamura Chemical Industries, Ltd.) (6 functional) 44.8 parts by mass Irgacure 184: Alkylphenone photopolymerization initiator (manufactured by BASF) 4 parts by mass 3,4-epoxycyclohexylmethyl methacrylate: Cyclomer M100 ( Daicel Corporation, molecular weight 196) 2.5 parts by mass Compound 1 0.80 parts by mass Polymer surfactant B1176 (Dainippon Chemical Industry Co., Ltd.)
0.05 parts by mass MEK-AC-2140Z (average particle size 10 to 20 nm,
Spherical silica fine particles (manufactured by Nissan Chemical Industries, Ltd.) 8.08 parts by mass - Tinuvin928: benzotriazole ultraviolet absorber (manufactured by BASF) 1.15 parts by mass - Silica particle dispersion (MiBK solution, concentration 5%) 13 parts by mass The solvent was adjusted so that MEK:MiBK:methyl acetate=32:38:30.

Compound 1:
The above compound 1 was synthesized by the method described in Example 1 of Japanese Patent No. 4841935.

<Preparation of retardation layer>
(1) The cellulose acylate film 1 on which the above-mentioned alignment film was formed was used as a support, and one side of the cellulose acylate film 1 was rotated clockwise with respect to the longitudinal direction of the support when viewed from the coated surface (Fig. A rubbing process was performed on α: rotation angle, H: long side direction, Sa: rubbing direction). The rubbing treatment was performed using a rayon cloth under the following conditions: pressure: 0.1 kgf (0.98 N), rotation speed: 1000 rpm (revolutions per minute), conveyance speed: 10 m/min, and number of times: 1 reciprocation.
Table 1 shows the angles (azimuth angles (α in FIG. 2)) rotated during the rubbing process of Examples 1 to 28, Examples 32 to 50, and Examples 54 to 69.

(2) In Examples 1 to 24, a tilted retardation layer was first formed.
A coating solution for forming an inclined retardation layer was applied to the rubbed surface of the alignment film on the cellulose acylate film 1 using a wire bar.
Thereafter, the coating solution for forming the inclined retardation layer was dried and placed on a hot plate at 50°C, and in an environment with an oxygen concentration of 1000 ppm or less, an electrodeless lamp "D Bulb" (60 mW/cm ^{2 )} manufactured by Fusion UV Systems was used. ) for 6 seconds to fix the liquid crystal phase to obtain a tilted retardation layer.
At this time, the retardation value was measured at three measurement angles of -40 degrees, 0 degrees, and +40 degrees when the normal direction of the inclined retardation layer was 0 degrees using AxoScan (manufactured by Axometrix), The angle of inclination θ1 of the upper surface of the retardation layer and the angle of inclination θ2 of the lower surface of the retardation layer were determined from fitting of the angle dependence of retardation. The average tilt angle of the rod-like liquid crystal compound in the tilted retardation layer was determined from the average value of the tilt angle θ1 and the tilt angle θ2. The average inclination angle (inclination angle) is shown in Table 1.
The frontal retardation at an inclination angle of 0 degrees was measured as follows. First, a plane was assumed whose rotation axis was in a direction perpendicular to the direction of the slow axis of the inclined retardation layer. Next, by this rotation axis, a plane was assumed to be inclined in the same direction as the inclination direction of the rod-like liquid crystal compound by the average inclination angle of the rod-like liquid crystal compound. The front retardation at an inclination angle of 0 degrees was measured by measuring the retardation using AxoScan (manufactured by Axometrix) with light incident from a direction perpendicular to this inclined plane. Table 1 shows the front retardation (front Re) at an inclination angle of 0 degrees.

In Examples 25 to 28, Examples 32 to 50, and Examples 54 to 69, a retardation layer was first formed.
A retardation layer was formed in the same manner as described above, except that a retardation layer forming coating liquid was used as the coating liquid. The front retardation of the formed retardation layer was measured using AxoScan (manufactured by Axometrics). Table 1 shows the measurement results of front retardation (front Re).
It was the same.

<Preparation of selective reflection layer>
(1) Examples 3, 8, 11, 15, 20, 23, 31, 32, 37, 38, 43, 44, 53, 54, 59, 60, 65, 66 and 69 are then made of cholesteric liquid crystals A circularly polarized light reflecting layer was formed.
Coating liquid 1 for forming a cholesteric liquid crystal layer was coated on the surface of the formed retardation layer using a wire bar at room temperature so that the dry film thickness after drying was 0.65 μm to obtain a coated layer. Regarding the solvent, the amount of the solvent was adjusted so that the solid content concentration was 25% by mass. After drying the coating layer at room temperature for 30 seconds, it was heated in an atmosphere of 85°C for 2 minutes, and then heated at 60°C in an environment with an oxygen concentration of 1000 ppm or less using a Fusion D bulb (90 mW/cm ² lamp). The cholesteric liquid crystal phase was fixed by irradiating ultraviolet rays at 60% output for 6 to 12 seconds to obtain a cholesteric liquid crystal layer with a thickness of 0.65 μm.
Next, on the surface of the obtained cholesteric liquid crystal layer, the same process was repeated using the coating liquid 2 for forming a cholesteric liquid crystal layer, and a layer of the coating liquid 1 for forming a cholesteric liquid crystal layer having a thickness of 0.71 μm was laminated.
The cholesteric liquid crystal layer formed with the coating liquid 1 for forming a cholesteric liquid crystal layer corresponds to the first selective reflection layer, and the cholesteric liquid crystal layer formed with the coating liquid 2 for forming the cholesteric liquid crystal layer corresponds to the second selective reflection layer.
In this way, a projection image display member with a support was obtained, which had a retardation layer and a selective reflection layer comprising two cholesteric liquid crystal layers, or further had a polarization conversion layer. When the reflection spectrum of the projection display member with the support was measured using a spectrophotometer (manufactured by JASCO Corporation, V-670), a reflection spectrum having selective reflection center wavelengths at a wavelength of 580 nm and a wavelength of 700 nm was obtained.
(2) Examples 2, 7, 10, 14, 19, 22, 27-30, 35, 36, 41, 42, 49-52, 57, 58, 63 and 64 formed linearly polarized light reflective layers.
As a linearly polarized light reflecting plate, 2,6- Polyethylene naphthalate (PEN) and copolyester of naphthalate 70/terephthalate 30 (coPEN) were prepared by adjusting the thickness of each layer.
Among these, for Examples 29 to 30 and Examples 51 to 52, the directions were rotated 45 degrees clockwise with respect to the longitudinal direction of the support when viewed from the coated surface (α in FIG. 2: rotation angle, H: It was produced in a direction that reflected S-polarized light in the long side direction (Sa: rubbing direction).
(3) Examples 4, 9, 12, 16, 21, 24, 33, 34, 39, 40, 45, 46, 55, 56, 61, 62, 67 and 68 are isotropic dielectric multilayer films. A non-polarized light reflecting layer was formed.
The non-polarized light reflecting layer was vacuum-deposited using an electron beam on the surface of the retardation layer at a vacuum degree of 1×10 ^-4 Pa and a substrate temperature of 25°C. The thickness of each layer was adjusted so that the selective reflection center wavelength was 670 nm and the reflectance was 32% due to the alternating layers of silicon oxide of the refractive vapor deposition material.

<Preparation of polarization conversion layer>
(1) For Examples 5, 7 to 9, 17, 19 to 21, 35 to 40, 57 to 62, and 69, polarization conversion layers made of a helical structure of cholesteric liquid crystal were produced.
A polarization conversion layer was formed on the surface of each sample using a coating liquid for forming a polarization conversion layer in the same manner as for forming the retardation layer so as to have the target thickness shown in Table 1.
(2) For Examples 6, 10 to 12, 18, 22 to 24, 29 to 31, 41 to 46, 51 to 53, and 63 to 68, polarization conversion layers consisting of retardation layers were produced.
After rubbing the alignment film on another cellulose acylate film 1 and producing a retardation layer with a desired front Re in the same manner as for forming the retardation layer, the retardation layer was applied to the surface of each sample by DIC Co., Ltd. UV curable adhesive Exp. It was adhered using U12034-6.

<Coating of hard coat layer>
A hard coat layer was prepared by using the hard coat layer coating liquid on the surface of the 40 μm cellulose acylate film in Examples 14 to 24 and Examples 49 to 69 on which the reflective layer was not formed.
Specifically, the hard coat liquid was applied using a bar at a transport speed of 10 m/min, dried at 60°C for 150 seconds, and then further under nitrogen purge with an oxygen concentration of about 0.1% by volume at 160 W/cm ² Using an air-cooled metal halide lamp (manufactured by Eye Graphics), the coated layer was cured by irradiating ultraviolet rays at an illuminance of 400 mW/cm ² and an irradiance of 500 mJ/cm ² to form a hard coat layer.

<Thickness of hard coat layer>
The film thickness of the hard coat layer was calculated by measuring the film thickness of the hard coat layer produced using a contact type film thickness meter, and subtracting the film thickness without the hard coat measured in the same manner from there. The thickness of the hard coat layer was 6.0 μm under all conditions.

Projection image display members with supports of Examples 1 to 69 were produced through the above steps.
Each level of the obtained elongated projection image display member was cut into a size of 280 mm in the longitudinal direction x 250 mm in the width direction to obtain a sheet-shaped projection image display member.

<Production of a member attached to wedge-shaped glass>
For the projected image display members of Examples 13 to 24 and Examples 47 to 69, glasses were produced in which the projected image display member was bonded to the surface of wedge-shaped glass. The wedge-shaped glass was produced as follows.
A polyvinyl butyral film (manufactured by Sekisui Chemical Co., Ltd., S-LEC Film, thickness 15 mil (0.38 mm)) was given a thickness distribution using a roller as described in Example 2 of JP-A-2-279437. Ta. A shape was formed using two polyvinyl butyral films with a thickness distribution as described above, and this was then sandwiched between two glass plates (FL2 manufactured by Central Glass Co., Ltd., 300 x 300 mm, thickness 2 mm). The angles of the front and back of the glass were adjusted to prevent the displayed image from being duplicated.
After holding this at 90°C and 10kPa (0.1 atm) for one hour, it was heated at 115°C and 1.3MPa (13 atm) for 20 minutes in an autoclave (manufactured by Kurihara Seisakusho) to remove air bubbles and form a wedge. Got the glass.
A UV-curable adhesive Exp. made by DIC was applied to the surface of the wedge-shaped glass. Each projection image display member was adhered using U12034-6. At this time, the retardation layer side was the incident side of the projection light, and the glass was bonded so that the direction of the azimuth angle of 0 degrees of the retardation layer and the vertical direction of the wedge-shaped glass coincided.

<Production of laminated glass>
For the projected image display members of Examples 1 to 12 and Examples 25 to 46, laminated glasses were produced in which the projected image display member was sandwiched between glasses.
A 0.38 mm thick PVB film (interlayer film) made by Sekisui Chemical Co., Ltd. cut to the same size was placed on a glass plate (manufactured by Central Glass Co., Ltd., FL2, visible light transmittance 90%) measuring 300 mm long x 300 mm wide and 2 mm thick. installed.
Each sheet-shaped projection image display member was installed with the retardation layer side facing upward, and a glass plate (manufactured by Central Glass Co., Ltd., FL2, visible light transmittance 90%) were installed. This was held at 90°C and 10 kPa (0.1 atm) for one hour, and then heated in an autoclave (manufactured by Kurihara Seisakusho) at 115°C and 1.3 MPa (13 atm) for 20 minutes to remove air bubbles and combine. Got the glass.
Figure 5 shows the structure of the laminated glass viewed from the side. FIG. 6 shows the relationship with the rubbing direction Sa viewed from the retardation layer side. The upper side in FIG. 6 was defined as the starting point side of rubbing, and the lower side was defined as the end point side of rubbing.

The produced wedge-shaped glass and laminated glass (windshield glass) were evaluated as follows.
[Evaluation of visible light transmittance]
As the visible light transmittance, the A light source visible light transmittance defined in JIS R 3212:2015 (automobile safety glass test method) was determined. Visible light transmittance was evaluated based on the following evaluation criteria.
Evaluation criteria for visible light transmittance A: 83% or more B: 80% or more and less than 82% C: less than 80% The evaluation results of visible light transmittance are shown in Table 2 below (Table 2-1 to Table 2-4).

[Evaluation of brightness when wearing polarized sunglasses]
As shown in Table 1, S-polarized light or right-handed circularly polarized light is incident from the glass surface on the retardation layer side at 65 degrees to the normal direction of the laminated glass, and the specularly reflected light (in the normal direction within the incident plane) is On the other hand, the reflectance spectrum was measured using a spectrophotometer (manufactured by JASCO Corporation, V-670) on the opposite side to the incident direction (65 degrees with respect to the normal direction). At this time, the long side direction of the projection image display member was made parallel to the transmission axis of the P-polarized light incident on the spectrophotometer. At this time, the axis H of the laminated glass and the vertical direction Y are in the same direction, and the upper side of the glass becomes the starting point side of the rubbing (see FIG. 7).
According to JIS R3106, the projected light reflectance was calculated by multiplying the reflectance by a coefficient according to visibility and the emission spectrum of a general liquid crystal display device at each wavelength of 10 nm from 380 to 780 nm, and evaluated as brightness. . The brightness was evaluated based on the following evaluation criteria.
Brightness evaluation criteria A: 20% or more (images are clearly visible even under clear skies)
B 11% or more - less than 20% (The image is visible. The image is somewhat difficult to see under clear skies.)
B- 7% or more to less than 11% (The image is visible. The image is difficult to see under clear skies.)
C+ 3% or more to less than 7% (You can see the image, but it is not visible under clear skies.)
C 3% or less (The image is almost invisible.)
The evaluation results of brightness are shown in Table 2 below (Table 2-1 to Table 2-4).

[Evaluation of double image]
An image with straight lines drawn in a grid was projected in the same arrangement as in the evaluation of brightness when wearing polarized sunglasses described above (FIG. 7), and a double image of the image was visually evaluated at the position of the spectrophotometer detector 41. The double image was evaluated based on the following evaluation criteria.
Evaluation criteria for double images A: No double images are visible and there is no blur in the straight line.
B: Double images are slightly visible, and straight lines appear a little thick.
C: A double image is clearly visible, and the straight line appears to be divided into two.
The evaluation results of the double image are shown in Table 2 below (Table 2-1 to Table 2-4).

[Evaluation of suitability of polarized sunglasses against external light]
S-polarized light is incident from the glass surface on the polarization conversion layer side from a direction of 65 degrees to the normal direction of the glass, and the P-polarized light of the transmitted light is measured from the side opposite to the incident surface of the laminated glass using a spectrophotometer (manufactured by JASCO Corporation, Transmittance spectra were measured with V-670).
At this time, a linear polarizing plate was placed in the light receiving section of the spectrophotometer to make the long side direction of the projection image display member parallel to the transmission axis of the P-polarized light entering the spectrophotometer (see FIG. 8). According to the observed JIS R3106, the visible light transmittance was calculated by multiplying the coefficient according to the visibility and the emission spectrum of the D65 light source at each wavelength of 10 nm from 380 to 780 nm, and the suitability of polarized sunglasses for external light was evaluated. . The suitability of polarized sunglasses for external light was evaluated based on the following evaluation criteria.
Evaluation criteria for the suitability of polarized sunglasses against external light (external light polarized sunglasses) A: Less than 3% B: 3% or more and less than 5% C: 5% or more The evaluation results of the suitability of polarized sunglasses against external light are shown in Table 2 (Table 2-1) below. Table 2-4).

[Evaluation of appearance color]
A blank sheet of paper was placed at a position where it could be seen by specular reflection from the glass surface on the polarization conversion layer side at 65 degrees with respect to the normal direction of the laminated glass, and the color tone was confirmed. The appearance color was evaluated based on the following evaluation criteria.
Evaluation criteria for appearance color A (white): White paper appears white.
B (yellow): The white paper looks slightly yellow. B (brown): The white paper looks slightly brown. C (red): The white paper looks strongly red. The evaluation results of the appearance color are shown in Table 2 below (Table 2-1 to Table 2). -4).

As shown in Table 2, Examples 1 to 69 had high visible light transmittance, and compared to the wedge-shaped glass of Comparative Example 1, good results were obtained in brightness when wearing polarized sunglasses. .
In Examples 5 to 12, Examples 17 to 24, Examples 35 to 46, and Examples 57 to 69, similar to the wedge-shaped glass of Comparative Example 1, good results were obtained in terms of suitability for polarized sunglasses for external light.
In addition, as shown in Example 20 and Example 69, by having an inclined retardation layer in which a rod-shaped liquid crystal compound is oriented obliquely with respect to the surface as a retardation layer, visible light transmittance can be improved when wearing polarized sunglasses. The display brightness and suitability of external light for polarized sunglasses, as well as the effect of reducing double images, can be made more suitable.

10 Projection image display member 11 Polarization conversion layer 12 Selective reflection layer 12G First selective reflection layer 12R Second selective reflection layer 14 Inclined retardation layer 15 Support 20 Head-up display system (HUD)
22 Projector 24 Windshield glass 25, 30a Surface 28 First glass plate 30 Second glass plate 36 Intermediate film 38 Adhesive layer 40 Spectrophotometer light source 41 Spectrophotometer detector 42 Linear polarizing plate 43 Rotation direction during measurement D Driver H Axis Sa Slow axis Y Vertical direction

Claims (17)

A projected image display member that is provided on a glass to constitute a projected image display section on the glass,
It has at least a retardation layer containing a rod-like liquid crystal compound, a selective reflection layer , and a polarization conversion layer ,
In the retardation layer, the rod-like liquid crystal compound is tilted in one direction with respect to the surface of the retardation layer,
The selective reflection layer has wavelength selectivity, and further has polarized light reflection, which transmits one of right-handed circularly polarized light and left-handed circularly polarized light and reflects the other, or transmits one of orthogonal linearly polarized lights and reflects the other. layer ,
The polarization conversion layer is a layer that has a fixed helical alignment structure of a liquid crystal compound and does not have wavelength selective reflection characteristics, and in the polarization conversion layer, the thickness and the helical alignment structure are determined by the director of the liquid crystal compound. The number of pitches, when one pitch of 360 degree rotation is set to 1, satisfies the following relational expressions (i) and (ii),
A projection display member for a head-up display system that is attached to the windshield glass.
When the pitch number of the polarization conversion layer is x and the film thickness is y (unit: μm)
(i) 0.1≦x≦2.0
(ii) 0.5≦y≦7.0 The average tilt angle of the rod-like liquid crystal compound in the retardation layer is 10 to 80 degrees with respect to the surface of the retardation layer,
The retardation layer has a front retardation of 100 to 500 nm at an inclination angle of 0 degrees, which is a retardation measured by entering light from a direction perpendicular to the direction of the average inclination angle on the surface of the retardation layer. The projection image display member according to claim 1. A projected image display member that is provided on a glass and constitutes a projected image display section on the glass,
having at least one retardation layer and a polarization conversion layer,
The front retardation of the retardation layer is 100 to 350 nm,
The polarization conversion layer is a layer that has a fixed helical alignment structure of a liquid crystal compound and does not have wavelength selective reflection characteristics, and in the polarization conversion layer, the thickness and the helical alignment structure are determined by the director of the liquid crystal compound. The number of pitches, when one pitch of 360 degree rotation is set to 1, satisfies the following relational expressions (i) and (ii),
A projection display member for a head-up display system that is attached to the windshield glass.
When the pitch number of the polarization conversion layer is x and the film thickness is y (unit: μm) (i) 0.1≦x≦2.0
(ii) 0.5≦y≦7.0 The projection image display member according to claim 3 , comprising a selective reflection layer. 5. The projection image display member according to claim 4 , wherein the selective reflection layer is a reflection layer that reflects linearly polarized light. When the upper part of the vertical direction when mounted on a vehicle is set to 0 degrees,
According to claim 5 , the direction of refractive index anisotropy of the linearly polarized light reflective layer is tilted clockwise at an angle of 10 to 80 degrees or 100 to 170 degrees when viewed from the projection image display side. The projection image display member described above. 5. The projection image display member according to claim 4 , wherein the selective reflection layer is a reflection layer that reflects circularly polarized light. 5. The projection image display member according to claim 4 , wherein the selective reflection layer is a non-polarized reflection layer. Polarized light reflection, in which the selective reflection layer has wavelength selectivity, and further transmits one of right-handed circularly polarized light and left-handed circularly polarized light and reflects the other, or transmits one of orthogonal linearly polarized lights and reflects the other. The projection image display member according to claim 4 , which is a layer. A windshield glass comprising a windshield glass body and the projection image display member according to any one of claims 1 to 9 . The windshield glass according to claim 10 , wherein the windshield glass body is laminated glass. The windshield glass according to claim 11 , wherein the windshield glass body is wedge-shaped glass. The windshield glass according to any one of claims 10 to 12 , wherein the projection image display member is adhered to the inner surface of the windshield glass body. The windshield glass according to claim 11 or 12 , wherein the projection image display member is held between the windshield glass body. The projected image display according to any one of claims 1 to 9 , comprising a wedge-shaped glass serving as a windshield glass, a projector that projects an image onto the wedge-shaped glass, and a projection surface of the wedge-shaped glass from which the image is projected from the projector. A head-up display system having a member for use. The head-up display system according to claim 15 , wherein the projector mainly emits S-polarized light. The head-up display system according to claim 15 , wherein the projector mainly emits circularly polarized light.