WO2017221760A1

WO2017221760A1 - Half mirror and mirror with image displaying function

Info

Publication number: WO2017221760A1
Application number: PCT/JP2017/021699
Authority: WO
Inventors: 広敏安藤; 田口　貴雄; 美喜男都丸
Original assignee: 富士フイルム株式会社
Priority date: 2016-06-21
Filing date: 2017-06-12
Publication date: 2017-12-28

Abstract

Provided are: a half mirror configured to have a reflective polarizing plate on a resin layer formed by processes including heating and pressing, and capable of presenting a uniform mirror reflection image; and a mirror with image displaying function displaying an image that presents a uniform mirror reflection image and a bright and uniform image. The half mirror includes an observation surface, a molded resin layer, and a reflective polarizing plate in this order and includes at least one high-Re phase difference film between the observation surface and the reflective polarizing plate, the sum of the front phase differences of the high-Re phase difference film being 3000 nm or greater. The half mirror includes a first high-Re phase difference film between the observation surface and the molded resin layer as the high-Re phase difference film.

Description

Half mirror and mirror with image display function

The present invention relates to a half mirror and a mirror with an image display function including the half mirror.

For example, Patent Document 1 describes a mirror with a vehicle image display function that can display an image such as an image captured by a vehicle-mounted camera on a vehicle mirror. In the mirror with a vehicle image display function disclosed in Patent Document 1, a liquid crystal display device is provided inside the housing of the vehicle mirror, and an image is displayed through a half mirror provided on the front surface of the vehicle mirror. The image display on the mirror is realized.

As a mirror with a display function, Patent Document 2 discloses a mirror with an information display function applied to interior, cosmetic, crime prevention, and safety mirrors, and a polarizing reflector is used as a half mirror. It is described.
As a method for manufacturing a mirror, as described in Patent Document 3, a method in which a reflective film is thermocompression bonded to a resin layer obtained by injection molding is known.

JP 2014-2011146 A JP 2011-45427 A Japanese Patent Application Laid-Open No. 2004-286943

When a metal-deposited mirror or the like is used as a half mirror in the vehicle image display function mirror described in Patent Document 1, the visible light transmittance is usually about 30% to 70%, and the image does not have a half mirror. There is a potential problem of becoming darker than things.
On the other hand, when a polarizing reflector as described in Patent Document 2 is used, light loss can be eliminated. Therefore, the present inventors produced a half mirror in which a polarizing reflector is provided on the surface of a resin layer obtained by injection molding as described in Patent Document 3. However, when the mirror reflection image of the obtained half mirror was observed through polarized sunglasses, uneven brightness was confirmed. Moreover, when the image of the mirror with an image display function produced using this half mirror was also observed through polarized sunglasses, light / dark unevenness or color unevenness (rainbow color, etc.) was confirmed.

An object of the present invention is to provide a half mirror that gives a mirror reflection image without unevenness as a half mirror having a polarizing reflector on a resin layer formed by processing including heating and pressing. Furthermore, the present invention provides a mirror with an image display function including a half mirror having a polarizing reflector on a resin layer formed by processing including heating and pressurization, as well as a non-uniform mirror reflection image, and a bright, non-uniformity. It is an object of the present invention to provide a mirror with an image display function that gives a non-image.

The present inventors diligently studied to solve the above problems and completed the present invention.
The present invention provides the following [1] to [19].
[1] An observation surface, a molded resin layer, and a polarizing reflector are included in this order,
Including at least one high Re retardation film between the observation surface and the polarizing reflector, the total front retardation of the high Re retardation film is 3000 nm or more,
A half mirror including a first high Re retardation film as the high Re retardation film between the observation surface and the molding resin layer.
[2] The half mirror according to [1], wherein the front phase difference distribution of the molded resin layer is 100 nm or more.
[3] The half mirror according to [1] or [2], wherein the total front retardation of the high Re retardation film is 5000 nm or more.

[4] The half mirror according to any one of [1] to [3], wherein the front phase difference of the first high Re retardation film is 3000 nm or more.
[5] The half mirror according to any one of [1] to [4], including only the first high Re retardation film as the high Re retardation film.
[6] The half according to any one of [1] to [4], further including a second high Re retardation film as the high Re retardation film between the molding resin layer and the polarizing reflector. mirror.
[7] The half mirror according to [6], wherein the direction of the slow axis of the first high Re retardation film is the same as the direction of the slow axis of the second high Re retardation film.
[8] The half mirror according to [6] or [7], including an adhesive layer or a thermoplastic weld layer between the second high Re retardation film and the molded resin layer.

[9] Any one of [1] to [8], wherein the molded resin layer includes one or more polymers selected from the group consisting of polycarbonate, poly (meth) acrylate, polyester, and cycloolefin polymer. Half mirror described.
[10] The half mirror according to any one of [1] to [9], wherein the polarizing reflector is a circularly polarizing reflecting layer.
[11] The half mirror according to [10], wherein the circularly polarized light reflecting layer includes a cholesteric liquid crystal layer.
[12] The half mirror according to [11], wherein the circularly polarized light reflection layer includes three or more cholesteric liquid crystal layers.
[13] Further includes a quarter wave plate,
The half mirror according to any one of [10] to [12], including the molded resin layer, the polarizing reflector, and the quarter-wave plate in this order.
[14] The half mirror according to [13], wherein the polarizing reflector and the quarter-wave plate are in direct contact with each other.

[15] The half mirror according to any one of [1] to [14], which includes an adhesive layer or a thermoplastic weld layer between the molded resin layer and the polarizing reflector.
[16] The half mirror according to any one of [1] to [15], which includes an adhesive layer or a thermoplastic weld layer between the first high Re retardation film and the molded resin layer.
[17] The half mirror according to any one of [1] to [16] and an image display device,
A mirror with an image display function in which the observation surface, the molded resin layer, the polarizing reflector, and the image display device are arranged in this order.
[18] The image display device emits linearly polarized light to form an image,
The image display device has a backlight that gives a continuous emission spectrum,
The mirror with an image display function according to [17], wherein a slow axis of the first high Re retardation film forms an angle of 30 ° to 60 ° with a polarization direction of the linearly polarized light.
[19] The mirror with an image display function according to [18], wherein the image display device is a liquid crystal display device, and the backlight is a white LED.

According to the present invention, it is possible to provide a half mirror that gives a mirror reflection image without unevenness as a half mirror having a polarizing reflector on a resin layer formed by processing including heating and pressing. Moreover, as a mirror with an image display function including a half mirror having a polarizing reflector on a resin layer formed by processing including heating and pressurization, a bright and non-uniform image is displayed together with a non-uniform mirror reflection image. A mirror with an image display function can be provided.

Hereinafter, the present invention will be described in detail.
In the present specification, “to” is used in the sense of including the numerical values described before and after it as lower and upper limits.
In this specification, for example, an angle such as “45 °”, “parallel”, “vertical” or “orthogonal” is within a range where the difference from the exact angle is less than 5 ° unless otherwise specified. Means. The difference from the exact angle is preferably less than 4 °, more preferably less than 3 °.
In the present specification, the description of “(meth) acrylate” represents the meaning of “any one or both of acrylate and methacrylate”. The same applies to “poly (meth) acrylate” and the like.

In this specification, “selective” for circularly polarized light means that either the right circularly polarized light component or the left circularly polarized light component has more light than the other circularly polarized light component. Specifically, when referred to as “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. It is particularly preferred that it is substantially 1.0. Table In _{_{/ (I R + I L)}} | Here, the degree of circular polarization, the intensity of the right circularly polarized light component of the light I _R, when the strength of the left-handed circularly polarized light component and I _{_L,} | I _R -I _L Is the value to be

In this specification, “sense” for circularly polarized light means right circularly polarized light or left circularly polarized light. The sense of circularly polarized light is right-handed circularly polarized light when the electric field vector tip turns clockwise as time increases when viewed as the light travels toward you, and left when it turns counterclockwise. Defined as being circularly polarized.

In this specification, the term “sense” is sometimes used for the twist direction of the spiral of the cholesteric liquid crystal. When the twist direction (sense) of the spiral of the cholesteric liquid crystal is right, the right circular polarized light is reflected and the left circular polarized light is transmitted. When the spiral sense of the cholesteric liquid crystal is on the left, it reflects left circularly polarized light and transmits right circularly polarized light.

In the present specification, the front phase difference is a value measured using an AxoScan manufactured by Axometrics. The measurement wavelength is 550 nm unless otherwise specified. The front phase difference is a value measured by making light in a wavelength range of visible light such as the central wavelength of selective reflection of the cholesteric liquid crystal layer incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments). You can also When selecting the measurement wavelength, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like. In the present specification, the front phase difference is sometimes referred to as “Re”.

In this specification, “mirror reflection image” means an image observed based on reflection from a half mirror. The mirror reflection image only needs to be observed on the observation surface. In this specification, the term “image” refers to an image of an image display device or an image of an image display device that is observed by a mirror with an image display function when the image is displayed on an image display unit of the image display device. It means the image of origin.

<< Half Mirror >>
In this specification, a half mirror means a mirror having a function of reflecting light and a function of transmitting at least part of light having a desired wavelength.
The half mirror of the present invention includes an observation surface, a molded resin layer, and a polarizing reflector in this order, and further includes a high Re retardation film. The half mirror may include other layers such as an optical functional layer, an adhesive layer, and a thermoplastic welding layer.

The half mirror of this invention should just use the outermost surface which is a shaping | molding resin layer side seeing from a polarizing reflective plate as an observation surface. In the present specification, the observation surface is a surface on the side where the mirror reflection image is observed, and means the reflection surface of the half mirror.
The shape of a half mirror should just be a thing according to a use, and is not specifically limited, It is preferable that it is plate shape or film shape. The half mirror may have a curved surface. That is, the half mirror may be flat or curved. In particular, a curved shape can be designed with a free-form surface such as a polynomial aspherical surface or a Zernike polynomial surface according to the required optical performance other than the spherical surface. In a vehicle mirror application, a shape in which the observation surface is a convex curved surface is preferable.

<Molded resin layer (molten resin)>
In the present specification, the molded resin layer means a resin layer molded by processing including heating and pressing. The molded resin layer is preferably obtained by injection molding. The method for producing the molded resin layer will be described later.
The shape of the molded resin layer is not particularly limited, and is preferably a plate shape or a film shape. The molded resin layer may have a curved surface. That is, the molded resin layer may be flat or curved.

In the half mirror of the present invention, a transparent resin layer in the visible light region is used as the molded resin layer. Here, being transparent in the visible light region means that the light transmittance in the visible light region is 80% or more, preferably 85% or more. The light transmittance used as a scale of transparency is obtained by the method described in JIS A5759. That is, the transmittance obtained at a wavelength of 380 nm to 780 nm is measured with a spectrophotometer, and the weight obtained from the spectral distribution of CIE (International Commission on Illumination) daylight D65, the wavelength distribution of CIE light adaptation standard relative luminous sensitivity, and the wavelength interval. The light transmittance is obtained by multiplying the coefficient and performing a weighted average.

The molded resin layer is likely to have non-uniform birefringence due to processing including heating and pressing. For example, the front retardation distribution of the molded resin layer is preferably 50 nm or more, and particularly preferably 100 nm or more. The distribution of the front retardation of the molded resin layer is preferably about 500 nm at the maximum. Here, as shown in the embodiment, the distribution of the front phase difference is obtained by measuring the front phase difference of the measurement object divided into nine equal parts and calculating the difference between the maximum value and the minimum value.

The thickness of the molded resin layer may be about 100 μm to 10 mm, preferably 200 μm to 5.0 mm, more preferably 500 μm to 4.0 mm, and still more preferably 1.0 mm to 3.0 mm.

Examples of the material for forming the molded resin layer include thermoplastic resins and thermosetting resins. In the case of a thermosetting resin, the material for forming the molded resin layer may contain a monomer having a polymerizable group. As a material for forming the molded resin layer, a thermoplastic resin is preferable. The material for forming the molded resin layer is a resin that is generally used for injection molding because it is, for example, a resin that is injected into a mold in the manufacture of the molded resin layer. The material for forming the molded resin layer is used as a molten resin heated to the melting point or higher when forming the molded resin layer.

Examples of the thermoplastic resin include polycarbonate (PC), poly (meth) acrylate, polyester such as polyethylene terephthalate (PET), and cycloolefin polymer (COP). Examples of thermosetting resins include phenolic resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, diallyl phthalate resins, polyurethane resins, and silicone resins.

Of these, polycarbonate, poly (meth) acrylate, polyester, and cycloolefin polymer are preferable as the material for forming the molded resin layer, poly (meth) acrylate or polycarbonate is more preferable, and polycarbonate is more preferable.
Examples of commercially available thermoplastic resins include Iupilon S3000 l (polycarbonate, manufactured by Mitsubishi Engineering Plastics), Novalex 7022-l (polycarbonate, manufactured by Mitsubishi Engineering Plastics), Sumipex MG5 (poly (meth) acrylate, Sumitomo Chemical Co., Ltd.), PETG K2012 (polyethylene terephthalate, Eastman Chemical Co., Ltd.), Zeonex E48R (cycloolefin polymer, Nippon Zeon Co., Ltd.), Panlite L-1250Z100 (Polycarbonate, Teijin Ltd.), DURBIO T744OIR ( Polycarbonate, manufactured by Mitsubishi Chemical Corporation) can be used.

<Polarized reflector: linearly polarized reflective layer>
Examples of the polarizing reflector include a linearly polarized light reflecting layer and a circularly polarized light reflecting layer.
Examples of the linearly polarized light reflecting layer include (i) a linearly polarized light reflecting plate having a multilayer structure, (ii) a polarizer in which thin films having different birefringence are laminated, (iii) a wire grid polarizer, (iv) a polarizing prism, (v) Examples include a scattering anisotropic polarizing plate.

(I) Examples of the linearly polarized light reflecting plate having a multilayer structure include those obtained by laminating a plurality of dielectric thin films having different refractive indexes. In order to obtain a wavelength selective reflection film, it is preferable to alternately stack a plurality of high-refractive-index dielectric thin films and low-refractive-index dielectric thin films. It may be. The number of laminated layers is preferably 2 to 20 layers, more preferably 2 to 12 layers, still more preferably 4 to 10 layers, and particularly preferably 6 to 8 layers. By making the number of layers 20 or less, it is possible to prevent a decrease in production efficiency due to multilayer deposition.

The order of stacking the dielectric thin films is not particularly limited and can be appropriately selected depending on the purpose. For example, when the refractive index of an adjacent film is high, a film having a lower refractive index is first stacked. . Conversely, if the refractive index of the adjacent layer is low, a film having a higher refractive index is first deposited. The standard for the boundary of the refractive index is 1.8. Note that the refractive index level is not absolute, and among the high refractive index materials, there may be a relatively high refractive index and a low refractive index, or these may be used alternately. .

Examples of the material for the high refractive index dielectric thin film include Sb ₂ O ₃ , Sb ₂ S ₃ , Bi ₂ O ₃ , CeO ₂ , CeF ₃ , HfO ₂ , La ₂ O ₃ , Nd ₂ O ₃ , and Pr _6. O ₁₁ , Sc ₂ O ₃ , SiO, Ta ₂ O ₅ , TiO ₂ , TlCl, Y ₂ O ₃ , ZnSe, ZnS, ZrO ₂ and the like can be mentioned. Among these, Bi ₂ O ₃ , CeO ₂ , CeF ₃ , HfO ₂ , SiO, Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , ZnSe, ZnS, ZrO ₂ are preferable, and SiO, Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , ZnSe, ZnS and ZrO ₂ are particularly preferred.

Examples of the material for the low refractive index dielectric thin film include Al ₂ O ₃ , BiF ₃ , CaF ₂ , LaF ₃ , PbCl ₂ , PbF ₂ , LiF, MgF ₂ , MgO, NdF ₃ , SiO ₂ , Si ₂ O. ₃ , NaF, ThO ₂ , ThF _{4 and the} like. Among these, Al ₂ O ₃ , BiF ₃ , CaF ₂ , MgF ₂ , MgO, SiO ₂ and Si ₂ O ₃ are preferable, and Al ₂ O ₃ , CaF ₂ , MgF ₂ , MgO, SiO ₂ and Si ₂ O ₃ are preferable. Is particularly preferred.
The material of the dielectric thin film is not particularly limited with respect to the atomic ratio, and can be appropriately selected according to the purpose. The atomic ratio can be adjusted by changing the atmospheric gas concentration during film formation.

The method for forming the dielectric thin film is not particularly limited and can be appropriately selected depending on the purpose. For example, physical vapor deposition such as ion plating, vacuum deposition such as ion beam, sputtering, etc. (PVD method), chemical vapor deposition method (CVD method) and the like. Among these, the vacuum evaporation method and the sputtering method are preferable, and the sputtering method is particularly preferable.
As the sputtering method, a DC sputtering method having a high film formation rate is preferable. In the DC sputtering method, it is preferable to use a material having high conductivity.
In addition, as a method for forming a multilayer film by a sputtering method, for example, (1) a one-chamber method for forming a film alternately or sequentially from a plurality of targets in one chamber, and (2) a continuous film formation in a plurality of chambers. There is a multi-chamber method. Among these, the multi-chamber method is particularly preferable from the viewpoint of productivity and the viewpoint of preventing material contamination.
The thickness of the dielectric thin film is preferably λ / 16 to λ, more preferably λ / 8 to 3λ / 4, and more preferably λ / 6 to 3λ / 8 in the optical wavelength order.

The light propagating in the dielectric deposition layer is determined by the product of the thickness of the dielectric thin film and the refractive index of the film with respect to the light due to multiple reflections of part of the light for each dielectric thin film. Only light of a wavelength is selectively transmitted. Further, the central transmission wavelength of the dielectric vapor deposition layer has an angle dependency with respect to the incident light, and the transmission wavelength can be changed by changing the incident light.

(Ii) As a polarizer in which thin films having different birefringence are laminated, for example, those described in JP-T-9-506837 can be used. Specifically, when processed under conditions selected to obtain a specific refractive index relationship, a polarizer can be formed using a wide variety of materials. In general, it is preferred that one of the first materials has a different refractive index than the second material in the chosen direction. This difference in refractive index can be achieved in a variety of ways, including stretching, extrusion, or coating during or after film formation. Furthermore, it is preferred to have similar rheological properties (eg, melt viscosity) so that the two materials can be coextruded.
Commercially available products can be used as the polarizer in which thin films having different birefringence are laminated. Examples of commercially available products include DBEF (registered trademark) (manufactured by 3M).

(Iii) A wire grid polarizer is a polarizer that transmits one of polarized light and reflects the other by birefringence of a fine metal wire.
The wire grid polarizer is a periodic arrangement of metal wires, and is mainly used as a polarizer in the terahertz wave band. In order for the wire grid to function as a polarizer, it is preferable that the wire interval is sufficiently smaller than the wavelength of the incident electromagnetic wave.
In the wire grid polarizer, metal wires are arranged at equal intervals. The polarization component in the polarization direction parallel to the longitudinal direction of the metal wire is reflected by the wire grid polarizer, and the polarization component in the perpendicular polarization direction is transmitted through the wire grid polarizer.

As the wire grid polarizer, a commercially available product can be used, and examples of the commercially available product include a wire grid polarizing filter 50 × 50, NT46-636 manufactured by Edmund Optics.

<Polarized reflector: Circularly polarized reflective layer>
By using the circularly polarized light reflecting layer, incident light from the molding resin layer side can be reflected as circularly polarized light. Moreover, when using a half mirror for a mirror with an image display function, incident light from the image display device can be transmitted as circularly polarized light. Therefore, in a half mirror using a circularly polarized reflection layer and a mirror with an image display function using this half mirror, an image and a mirror reflection image can be observed through polarization sunglasses without depending on the direction. it can.

Examples of the circularly polarized light reflecting layer include a laminated circularly polarized light reflecting layer including a linearly polarized light reflecting plate and a quarter wavelength plate, and a cholesteric circularly polarized light reflecting layer including a cholesteric liquid crystal layer.

[Laminated circularly polarized light reflection layer including linearly polarized light reflection plate and quarter wave plate]
In the laminated circularly polarized light reflecting layer, the linearly polarized light reflecting plate and the quarter wavelength plate are arranged so that the slow axis of the quarter wavelength plate is 45 ° with respect to the polarized light reflecting axis of the linearly polarized light reflecting plate. That's fine. Moreover, the quarter wave plate and the linearly polarized light reflecting plate may be bonded by, for example, an adhesive layer.
When a half mirror is used for a mirror with an image display function, the linearly polarized light reflection plate is arranged and used in the laminated circularly polarized light reflection layer so as to be a surface close to the image display device. As a result, light for image display from the image display device can be efficiently converted into circularly polarized light and emitted from the observation surface of the mirror with an image display function. When the light for image display from the image display device is linearly polarized light, the polarization reflection axis of the linearly polarized light reflecting plate may be adjusted so as to transmit this linearly polarized light.
The thickness of the circularly polarized light reflecting layer including the linearly polarized light reflecting plate and the quarter wavelength plate is preferably in the range of 2.0 μm to 300 μm, more preferably in the range of 8.0 μm to 200 μm.
As the linearly polarized light reflecting plate, those described above as the linearly polarized light reflecting layer can be used.
As the quarter wavelength plate, a quarter wavelength plate described later can be used.

[Cholesteric circularly polarized reflective layer]
The cholesteric circularly polarized light reflection layer includes at least one cholesteric liquid crystal layer. The cholesteric liquid crystal layer included in the cholesteric circularly polarized light reflection layer may be any layer that exhibits selective reflection in the visible light region.
The circularly polarized light reflecting layer may include two or more cholesteric liquid crystal layers, and may include other layers such as an alignment layer. The circularly polarized light reflecting layer is preferably composed only of a cholesteric liquid crystal layer. Further, when the circularly polarized light reflection layer includes a plurality of cholesteric liquid crystal layers, it is preferable that they are in direct contact with adjacent cholesteric liquid crystal layers. The circularly polarized light reflection layer preferably includes three or more cholesteric liquid crystal layers such as three layers and four layers.
The thickness of the cholesteric circularly polarized light reflecting layer is preferably in the range of 1.0 μm to 300 μm, more preferably in the range of 1.5 μm to 100 μm, and still more preferably in the range of 2.0 μm to 20 μm.

In this specification, a cholesteric liquid crystal layer means a layer in which a cholesteric liquid crystal phase is fixed. The cholesteric liquid crystal layer is sometimes simply referred to as a liquid crystal layer.
The cholesteric liquid crystal phase selectively reflects circularly polarized light of either right circularly polarized light or left circularly polarized light in a specific wavelength region and selectively transmits circularly polarized light of the other sense. It is known to show. In this specification, the circularly polarized light selective reflection is sometimes simply referred to as selective reflection.

Many films formed from a composition containing a polymerizable liquid crystal compound have been known as films containing a layer in which a cholesteric liquid crystal phase exhibiting circularly polarized light selective reflection is fixed. For cholesteric liquid crystal layers, those conventional techniques are known. Can be referred to.

The cholesteric liquid crystal layer may be a layer that maintains the orientation of the liquid crystal compound that is in the cholesteric liquid crystal phase. Typically, a polymerizable liquid crystal compound is brought into an orientation state of a cholesteric liquid crystal phase, and then polymerized and cured by ultraviolet irradiation, heating, etc. to form a non-flowable layer, and simultaneously aligned by an external field or an external force. Any layer may be used as long as the shape is not changed. 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 may no longer exhibit liquid crystallinity. 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.

The central wavelength λ of selective reflection of the cholesteric liquid crystal layer depends on the pitch P (= spiral period) of the helical structure in the cholesteric liquid crystal phase, and follows the relationship between the average refractive index n of the cholesteric liquid crystal layer and λ = n × P. The selective reflection center wavelength and the half width of the cholesteric liquid crystal layer can be obtained as follows.
When the transmission spectrum of the light reflection layer (measured from the normal direction of the cholesteric liquid crystal layer) is measured using a spectrophotometer UV3150 (Shimadzu Corporation), a peak of reduced transmittance is observed in the selective reflection region. Of the two wavelengths having a transmittance of ½ of the largest peak height, the wavelength value on the short wavelength side is λ _l (nm), and the wavelength value on the long wavelength side is λ _h (nm ), The center wavelength and the full width at half maximum of selective reflection can be expressed by the following equations.
Selective reflection center wavelength = (λ _l + λ _h ) / 2 half width = (λ _h −λ _l )
The center wavelength λ of selective reflection possessed by the cholesteric liquid crystal layer, obtained as described above, usually coincides with the wavelength at the center of gravity of the reflection peak of the circularly polarized reflection spectrum measured from the normal direction of the cholesteric liquid crystal layer. In the present specification, the center wavelength of selective reflection means the center wavelength when measured from the normal direction of the cholesteric liquid crystal layer.
As can be seen from the above equation, the center wavelength of selective reflection can be adjusted by adjusting the pitch of the helical structure. The center wavelength λ can be adjusted in order to selectively reflect either the right circularly polarized light or the left circularly polarized light with respect to light of a desired wavelength by adjusting the n value and the P value.

When light is incident on the cholesteric liquid crystal layer at an angle, the center wavelength of selective reflection is shifted to the short wavelength side. Therefore, it is preferable to adjust n × P so that λ calculated according to the above formula λ = n × P becomes a long wavelength with respect to the wavelength of selective reflection required for image display. In the cholesteric liquid crystal layer having a refractive index n ₂ , the center wavelength of selective reflection when a light beam passes at an angle of θ ₂ with respect to the normal direction of the cholesteric liquid crystal layer (helical axis direction of the cholesteric liquid crystal layer) is λ _d . Λ _d is expressed by the following equation.
λ _d = n ₂ × P × cos θ ₂

When the half mirror of the present invention is used for a mirror with an image display function, the central wavelength of selective reflection of the cholesteric liquid crystal layer included in the circularly polarized light reflection layer is designed in consideration of the above, thereby making it possible to see the image from an oblique direction. Can be prevented. Also, the visibility of the image from an oblique direction can be intentionally reduced. Further, due to the selective reflection property described above, in the half mirror of the present invention or the mirror with an image display function including the half mirror of the present invention, a color may appear in an image viewed from an oblique direction or a mirror reflection image. By including a cholesteric liquid crystal layer having a central wavelength of selective reflection in the infrared light region in the circularly polarized light reflecting layer, it is possible to prevent such a color. In this case, the center wavelength of selective reflection in the infrared region is specifically 780 to 900 nm, preferably 780 to 850 nm.
When a cholesteric liquid crystal layer having a central wavelength of selective reflection is provided in the infrared light region, it is preferably outermost with respect to all the cholesteric liquid crystal layers each having a central wavelength of selective reflection in the visible light region. More preferably in a distant layer.

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 the concentration of the chiral agent, a desired pitch can be obtained by adjusting these. For the method of measuring spiral sense and pitch, use the methods described in “Introduction to Liquid Crystal Chemistry Experiments” edited by the Japanese Liquid Crystal Society, Sigma Publishing 2007, page 46, and “Liquid Crystal Handbook”, Liquid Crystal Handbook Editorial Committee, Maruzen, page 196. be able to.

In the half mirror, the circularly polarized light reflection layer includes a cholesteric liquid crystal layer having a central wavelength of selective reflection in the wavelength range of red light, a cholesteric liquid crystal layer having a central wavelength of selective reflection in the wavelength range of green light, and a wavelength of blue light. And a cholesteric liquid crystal layer having a central wavelength of selective reflection in the region. The reflective layer is, for example, a cholesteric liquid crystal layer having a central wavelength of selective reflection in 400 nm to 500 nm, a cholesteric liquid crystal layer having a central wavelength of selective reflection in 500 nm to 580 nm, and a cholesteric liquid crystal having a central wavelength of selective reflection in 580 nm to 700 nm. It is preferable to include a layer.

Further, when the circularly polarized light reflecting layer includes a plurality of cholesteric liquid crystal layers, it is preferable that the cholesteric liquid crystal layer closer to the image display device has a longer selective reflection center wavelength. With such a configuration, it is possible to suppress an oblique color tone in an image.

In particular, in a mirror with an image display function using a cholesteric circularly polarized reflection layer that does not include a quarter-wave plate, the center wavelength of selective reflection that each cholesteric liquid crystal layer has is 5 nm or more with the wavelength of the emission peak of the image display device. It is preferable to make them different. This difference is more preferably 10 nm or more. By shifting the center wavelength of selective reflection and the wavelength of the emission peak for image display of the image display device, the light for image display is not reflected by the cholesteric liquid crystal layer, and the display image can be brightened. The wavelength of the emission peak of the image display device can be confirmed by the emission spectrum when the image display device displays white. The peak wavelength may be any peak wavelength in the visible light region of the emission spectrum. For example, the above-described red light emission peak wavelength λR, green light emission peak wavelength λG, and blue light emission peak wavelength λB of the image display device. Any one or more selected from the group consisting of: The selective reflection center wavelength of the cholesteric liquid crystal layer is different from the above-described red light emission peak wavelength λR, green light emission peak wavelength λG, and blue light emission peak wavelength λB of the image display device by 5 nm or more. It is preferable that the difference is 10 nm or more. When the circularly polarized light reflection layer includes a plurality of cholesteric liquid crystal layers, the central wavelength of selective reflection of all the cholesteric liquid crystal layers is preferably 5 nm or more, more preferably 10 nm or more, with the peak wavelength of light emitted from the image display device. It should be different. For example, when the image display device is a full-color display device showing an emission peak wavelength λR of red light, an emission peak wavelength λG of green light, and an emission peak wavelength λB of blue light in the emission spectrum during white display, All of the central wavelengths of selective reflection of the cholesteric liquid crystal layer may be different from each of λR, λG, and λB by 5 nm or more, more preferably by 10 nm or more. Further, when the circularly polarized light reflecting layer includes three cholesteric liquid crystal layers having different central wavelengths of selective reflection represented by λ1, λ2, and λ3, the relationship of λB <λ1 <λG <λ2 <λR <λ3 is established. It is preferable that it is satisfy | filled.

When a half mirror is used as a mirror with an image display function, light is used by adjusting the center wavelength of selective reflection of the cholesteric liquid crystal layer to be used according to the emission wavelength range of the image display device and the usage mode of the circularly polarized reflection layer. A bright image can be displayed efficiently. Examples of the usage of the circularly polarized light reflecting layer include an incident angle of light to the circularly polarized light reflecting layer, an image observation direction, and the like.

As each cholesteric liquid crystal layer, a cholesteric liquid crystal layer whose spiral sense is either right or left is used. The sense of reflected circularly polarized light in the cholesteric liquid crystal layer coincides with the sense of a spiral. The spiral senses of the plurality of cholesteric liquid crystal layers may all be the same or different. In other words, either the right or left sense cholesteric liquid crystal layer may be included, or both the right and left sense cholesteric liquid crystal layers may be included. However, in the mirror with an image display function including a quarter wavelength plate, it is preferable that the spiral senses of the plurality of cholesteric liquid crystal layers are all the same. The spiral sense at that time may be determined according to the sense of circularly polarized light of the sense obtained as each cholesteric liquid crystal layer emitted from the image display device and transmitted through the quarter-wave plate. Specifically, a cholesteric liquid crystal layer having a spiral sense that transmits the circularly polarized light of the sense obtained from the image display device and transmitted through the quarter wavelength plate may be used.

The full width at half maximum Δλ (nm) of the selective reflection band showing selective reflection depends on the relationship of Δλ = Δn × P, where Δλ depends on the birefringence Δn of the liquid crystal compound and the pitch P. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Δn can be adjusted by adjusting the kind of the polymerizable liquid crystal compound and the mixing ratio thereof, or by controlling the temperature at the time of fixing the alignment.
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 spiral sense may be stacked. By laminating cholesteric liquid crystal layers having the same pitch P and the same spiral sense, the circularly polarized light selectivity can be increased at a specific wavelength.

<1/4 wavelength plate>
When the half mirror is used as a mirror with an image display function, the half mirror further includes a quarter wavelength plate, a molded resin layer, a polarizing reflector (preferably a circularly polarizing reflector layer, more preferably a cholesteric circularly polarizing reflector layer). ) And a quarter-wave plate in this order. It is preferable that the polarizing reflection plate and the quarter wavelength plate are in direct contact with each other. The quarter-wave plate is preferably disposed so as to be between the image display device and the cholesteric circularly polarizing reflection layer. By including a quarter-wave plate between the image display device and the cholesteric circularly polarized light reflection layer, in particular, the light from the image display device displaying an image by linearly polarized light is converted into circularly polarized light, and the cholesteric circularly polarized light is converted. It is possible to make the light incident on the reflective layer. Therefore, the light reflected by the circularly polarized light reflection layer and returning to the image display device side can be greatly reduced, and a bright image can be displayed. In addition, since a cholesteric circularly polarized light reflection layer can be configured not to generate sense circularly polarized light reflected to the image display device side by using a quarter wavelength plate, it is based on multiple reflections between the image display device and the half mirror. The image display quality is unlikely to deteriorate.
That is, for example, the center wavelength of selective reflection of the cholesteric liquid crystal layer included in the cholesteric circularly polarizing reflection layer is substantially the same as the emission peak wavelength of blue light in the emission spectrum during white display of the image display device (for example, the difference is less than 5 nm). Even in such a case, the emitted light of the image display device can be transmitted to the observation surface side without causing the circularly polarized light reflection layer to generate the sense circularly polarized light reflected to the image display side.

The quarter-wave plate used in combination with the cholesteric circularly polarized reflective layer is preferably angle-adjusted so that the image is brightest when bonded to the image display device. That is, the relationship between the polarization direction of the linearly polarized light (transmission axis) and the slow axis of the quarter-wave plate so that the linearly polarized light is transmitted best, particularly for an image display device displaying an image by linearly polarized light. Is preferably adjusted. For example, in the case of a single layer type quarter wave plate, it is preferable that the transmission axis and the slow axis form an angle of 45 °. The light emitted from the image display device displaying an image by linearly polarized light is circularly polarized light of either right or left sense after passing through the quarter wavelength plate. The circularly polarized light reflecting layer may be formed of a cholesteric liquid crystal layer having a twist direction that transmits the circularly polarized light having the above-described sense.

The quarter wave plate may be a retardation layer that functions as a quarter wave plate in the visible light region. Examples of the quarter wavelength plate include a single layer type quarter wavelength plate, a broadband quarter wavelength plate in which a quarter wavelength plate and a half wavelength plate are laminated, and the like.
The front phase difference of the former quarter-wave plate may be a length that is ¼ of the emission wavelength of the image display device. Therefore, for example, when the emission wavelength of the image display device is 450 nm, 530 nm, or 640 nm, the wavelength of 450 nm is preferably 112.5 nm ± 10 nm, more preferably 112.5 nm ± 5 nm, still more preferably 112.5 nm, 530 nm. Preferably at 132.5 nm ± 10 nm, more preferably at 132.5 nm ± 5 nm, more preferably at 132.5 nm and 640 nm, preferably at 160 nm ± 10 nm, more preferably at 160 nm ± 5 nm, more preferably at 160 nm. A reverse-dispersion retardation layer that is a phase difference is most preferable as the quarter-wave plate, but a retardation plate having a small retardation wavelength dispersion or a forward-dispersion retardation plate can also be used. The reverse dispersion means a property that the absolute value of the phase difference becomes larger as the wavelength becomes longer, and the forward dispersion means a property that the absolute value of the phase difference becomes larger as the wavelength becomes shorter.

The laminated quarter-wave plate is composed of a quarter-wave plate and a half-wave plate that are bonded to each other with the slow axis at an angle of 60 °, and the half-wave plate side is disposed on the incident side of linearly polarized light. In addition, the slow axis of the half-wave plate is used so as to cross 15 ° or 75 ° with respect to the polarization plane of the incident linearly polarized light, and is preferable because the reverse dispersion of the phase difference is good. Can be used.

There is no restriction | limiting in particular as a quarter wavelength plate, According to the objective, it can select suitably. For example, quartz plate, stretched polycarbonate film, stretched norbornene polymer film, transparent film containing inorganic particles exhibiting birefringence such as strontium carbonate, and oblique deposition of inorganic dielectric on support Thin films and the like.

Examples of the quarter-wave plate include (1) a birefringent film having a large retardation and a birefringence having a small retardation described in JP-A-5-27118 and JP-A-5-27119. A retardation film in which the optical axes are laminated so that their optical axes are orthogonal to each other; (2) a polymer film described in JP-A-10-68816 and having a quarter wavelength at a specific wavelength; And a retardation film which is obtained by laminating a polymer film made of the same material and having a ½ wavelength at the same wavelength to obtain a ¼ wavelength in a wide wavelength range, (3) JP-A-10-90521 (4) International Publication No. 00/26705 pamphlet, which can achieve a quarter wavelength in a wide wavelength range by laminating two polymer films. A retardation plate capable of achieving a quarter wavelength in a wide wavelength range using the modified polycarbonate film described above, (5) 1 in a wide wavelength range using a cellulose acetate film described in International Publication No. 00/65384 pamphlet And a retardation plate capable of achieving a / 4 wavelength.
A commercially available product can also be used as the ¼ wavelength plate. Examples of the commercially available product include Pure Ace (registered trademark) WR (polycarbonate film manufactured by Teijin Limited).

The quarter wavelength plate may be formed by arranging and fixing a polymerizable liquid crystal compound or a polymer liquid crystal compound. For example, for a quarter-wave plate, a liquid crystal composition is applied to the temporary support or the alignment film surface, and after forming a polymerizable liquid crystal compound in the liquid crystal composition in a nematic alignment in a liquid crystal state, photocrosslinking or thermal crosslinking is performed. Can be formed by immobilization. Details of the liquid crystal composition or the production method will be described later. The quarter-wave plate is aligned by applying a liquid crystal composition on the surface of a temporary support, support or alignment film to form a nematic alignment in a liquid crystal state and then cooling the composition containing a polymer liquid crystal compound. It may be a layer obtained by immobilizing.
The quarter wave plate may be adhered to the cholesteric circularly polarized light reflecting layer by an adhesive layer, or may be in direct contact with the latter, and the latter is preferred.

<Method for Producing 1/4 Wave Plate Formed from Cholesteric Liquid Crystal Layer and Liquid Crystal Composition>
Hereinafter, a preparation material and a preparation method of a quarter-wave plate formed from a cholesteric liquid crystal layer and a liquid crystal composition will be described.
Examples of the material used for forming the quarter wavelength plate include a liquid crystal composition containing a polymerizable liquid crystal compound. Examples of the material used for forming the cholesteric liquid crystal layer include a liquid crystal composition containing a chiral agent (optically active compound). If necessary, the above liquid crystal composition mixed with a surfactant or a polymerization initiator and dissolved in a solvent is used as a temporary support, a support, an alignment film, a lower cholesteric liquid crystal layer, a quarter-wave plate. After the alignment ripening, the liquid crystal composition is fixed by curing, and a cholesteric liquid crystal layer or a quarter wavelength plate can be formed.

[Polymerizable liquid crystal compound]
A rod-like liquid crystal compound may be used as the polymerizable liquid crystal compound.
Examples of the rod-like polymerizable liquid crystal compound include a rod-like nematic liquid crystal compound. Examples of rod-like nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only low-molecular liquid crystal compounds but also high-molecular liquid crystal compounds can be used.

The polymerizable liquid crystal compound can be obtained by introducing a polymerizable group into the liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, preferably an unsaturated polymerizable group, and particularly preferably an ethylenically unsaturated polymerizable group. The polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods. The number of polymerizable groups possessed by the polymerizable liquid crystal compound is preferably 1 to 6, more preferably 1 to 3. Examples of polymerizable liquid crystal compounds are described in Macromol. Chem. 190, 2255 (1989), Advanced Materials, 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, WO 95 / 22586A, WO 95 / 24455A. WO97 / 00600A, WO98 / 23580A, WO98 / 52905A, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, and JP-A-2001-328773. And the like. Two or more kinds of polymerizable liquid crystal compounds may be used in combination. When two or more kinds of polymerizable liquid crystal compounds are used in combination, the alignment temperature can be lowered.

The addition amount of the polymerizable liquid crystal compound in the liquid crystal composition is preferably 80% by mass to 99.9% by mass with respect to the solid content mass (mass excluding the solvent) of the liquid crystal composition, 85 It is more preferably from 9% by mass to 99.5% by mass, and particularly preferably from 90% by mass to 99% by mass.

[Chiral agent: optically active compound]
The liquid crystal composition used for forming the cholesteric liquid crystal layer preferably contains a chiral agent. The chiral agent has a function of inducing a helical structure of a cholesteric liquid crystal phase. The chiral compound may be selected according to the purpose because the helical sense or helical pitch induced by the compound is different.
There is no restriction | limiting in particular as a chiral agent, A well-known compound can be used. Examples of chiral agents include liquid crystal device handbook (Chapter 3, Section 4-3, TN, chiral agent for STN, page 199, edited by Japan Society for the Promotion of Science, 142th Committee, 1989), Japanese Patent Application Laid-Open No. 2003-287623. And compounds described in JP-A Nos. 2002-302487, 2002-80478, 2002-80851, 2010-181852 and 2014-034581.

A chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound containing no asymmetric carbon atom can also be used as the chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound 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, they are derived from the repeating unit derived from the polymerizable liquid crystal compound and the chiral agent by a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound. A polymer having repeating units can be formed. In this aspect, the polymerizable group possessed by the polymerizable chiral agent is preferably the same group as the polymerizable group possessed by the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred.
The chiral agent may be a liquid crystal compound.

As the chiral agent, an isosorbide derivative, an isomannide derivative, or a binaphthyl derivative can be preferably used. As the isosorbide derivative, a commercial product such as LC-756 manufactured by BASF may be used.
The content of the chiral agent in the liquid crystal composition is preferably from 0.01 mol% to 200 mol%, more preferably from 1.0 mol% to 30 mol%, based on the total molar amount of the polymerizable liquid crystal compound.

[Polymerization initiator]
The liquid crystal composition preferably contains a polymerization initiator. In the embodiment in which the polymerization reaction is advanced by ultraviolet irradiation, the polymerization initiator to be used is preferably a photopolymerization initiator capable of initiating the polymerization reaction by ultraviolet irradiation, and particularly preferably a radical photopolymerization initiator. Examples of radical photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substitution Aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850), acylphosphine oxide compounds (JP-B 63-40799, JP-B-5) -29234, JP-A-10-957 88, JP-A-10-29997), oxime compounds (JP-B 63-40799, JP-B 5-29234, JP-A 10-95788, JP-A 10-29997, JP-A 2001-233842). JP, 2000-80068, JP 2006-342166, JP 2013-114249, JP 2014-137466, JP 4223071, JP 2010-262028, and JP 2014-500852 Description) and oxadiazole compounds (described in US Pat. No. 4,221,970). For example, the description in paragraphs 0500 to 0547 of JP2012-208494A can be considered.

As the polymerization initiator, it is also preferable to use an acyl phosphine oxide compound or an oxime compound.
As the acylphosphine oxide compound, for example, IRGACURE819 (compound name: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide) manufactured by BASF Japan Ltd. can be used. Examples of the oxime compounds include IRGACURE OXE01 (manufactured by BASF), IRGACURE OXE02 (manufactured by BASF), TR-PBG-304 (manufactured by Changzhou Strong Electronic New Materials Co., Ltd.), Adeka Arcles NCI-831, Adeka Arcles NCI-930 Commercial products such as (ADEKA) and Adeka Arcles NCI-831 (ADEKA) can be used.

Only one type of polymerization initiator may be used, or two or more types may be used in combination.
The content of the polymerization initiator in the liquid crystal composition is preferably 0.1 to 20% by mass, and preferably 0.5 to 5.0% by mass with respect to the content of the polymerizable liquid crystal compound. Is more preferable.

[Crosslinking agent]
The liquid crystal composition may optionally contain a crosslinking agent in order to improve the film strength after curing and improve the durability. As the cross-linking agent, one that can be cured by ultraviolet rays, heat, moisture, or the like can be suitably used.
There is no restriction | limiting in particular as a crosslinking agent, According to the objective, it can select suitably, For example, polyfunctional acrylate compounds, such as a trimethylol propane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Glycidyl (meth) acrylate , Epoxy compounds such as ethylene glycol diglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane; hexa Isocyanate compounds such as methylene diisocyanate and biuret type isocyanate; polyoxazoline compounds having an oxazoline group in the side chain; vinyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylto Alkoxysilane compounds such as methoxy silane. Moreover, a well-known catalyst can be used according to the reactivity of a crosslinking agent, and productivity can be improved in addition to membrane strength and durability improvement. These may be used individually by 1 type and may use 2 or more types together.
The content of the crosslinking agent in the liquid crystal composition is preferably 3.0% by mass to 20% by mass, and more preferably 5.0% by mass to 15% by mass. When the content of the crosslinking agent is 3.0% by mass or more, an effect of improving the crosslinking density can be obtained. Moreover, the stability of the layer formed can be maintained by setting it as 20 mass% or less.

[Orientation control agent]
In the liquid crystal composition, an alignment control agent that contributes to stable or rapid planar alignment may be added. Examples of the alignment control agent include fluorine (meth) acrylate polymers described in paragraphs 0018 to 0043 of JP 2007-272185 A, and formulas (I) described in paragraphs 0031 to 0034 of JP 2012-203237 A, and the like. ) To (IV).
In addition, as an orientation control agent, 1 type may be used independently and 2 or more types may be used together.

The addition amount of the alignment control agent in the liquid crystal composition is preferably 0.01% by mass to 10% by mass and more preferably 0.01% by mass to 5.0% by mass with respect to the total mass of the polymerizable liquid crystal compound. 0.02% by mass to 1.0% by mass is particularly preferable.

[Other additives]
In addition, the liquid crystal composition may contain at least one selected from a surfactant for adjusting the surface tension of the coating film to make the thickness uniform, and various additives such as a polymerizable monomer. Further, in the liquid crystal composition, if necessary, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, metal oxide fine particles, and the like may be added as long as the optical performance is not deteriorated. Can be added.

[solvent]
There is no restriction | limiting in particular as a solvent used for preparation of a liquid-crystal composition, According to the objective, it can select suitably, An organic solvent is used preferably.
The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, ethers and the like. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, ketones are particularly preferable in consideration of environmental load.

[Coating, orientation, polymerization]
The method for applying the liquid crystal composition to the temporary support, the alignment film, the quarter-wave plate, the lower cholesteric liquid crystal layer, etc. is not particularly limited and can be appropriately selected according to the purpose. In addition to the application of the liquid crystal composition, the application method in this specification includes, for example, a wire bar coating method, a curtain coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method. , Spin coating method, dip coating method, spray coating method, slide coating method and the like. It can also be carried out by transferring a liquid crystal composition separately coated on a support. The liquid crystal compound is aligned by heating the applied liquid crystal composition. In forming the cholesteric liquid crystal layer, cholesteric alignment may be performed, and in forming the quarter-wave plate, nematic alignment is preferable. In the cholesteric orientation, the heating temperature is preferably 200 ° C. or lower, and more preferably 130 ° C. or lower. By this alignment treatment, an optical thin film in which the polymerizable liquid crystal compound is twisted and aligned so as to have a helical axis in a direction substantially perpendicular to the film surface is obtained. In the nematic orientation, the heating temperature is preferably 50 ° C. to 120 ° C., more preferably 60 ° C. to 100 ° C.

The aligned liquid crystal compound can be further polymerized to cure the liquid crystal composition. The polymerization may be either thermal polymerization or photopolymerization utilizing light irradiation, but photopolymerization is preferred. It is preferable to use ultraviolet rays for light irradiation. The irradiation energy is preferably ^{20mJ / cm 2 ~ 50J / cm} 2, 100mJ / cm 2 ~ 1,500mJ / cm 2 is more preferable. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions or in a nitrogen atmosphere. The irradiation ultraviolet wavelength is preferably 350 nm to 430 nm. The polymerization reaction rate is preferably high from the viewpoint of stability, more preferably 70% or more, and further preferably 80% or more. The polymerization reaction rate can be determined by measuring the consumption rate of the polymerizable group using an IR absorption spectrum.

The thickness of each cholesteric liquid crystal layer is not particularly limited as long as it exhibits the above characteristics, and is preferably in the range of 0.5 to 100 μm, more preferably in the range of 1.0 to 40 μm. The thickness of the quarter wave plate formed from the liquid crystal composition is not particularly limited, and is preferably 0.2 μm to 10 μm, more preferably 0.5 μm to 2.0 μm.

[Laminated film of layers formed from polymerizable liquid crystal compound]
When forming a multi-layer film composed of a plurality of cholesteric liquid crystal layers and a multi-layer film composed of a quarter-wave plate and a plurality of cholesteric liquid crystal layers, each is directly applied to the surface of the quarter-wave plate or the previous cholesteric liquid crystal layer. The liquid crystal composition containing a polymerizable liquid crystal compound or the like may be applied, and the steps of alignment and fixing may be repeated. A separately prepared quarter wave plate, cholesteric liquid crystal layer, or a laminate thereof is used with an adhesive or the like. The former is preferable. This is because the interference unevenness derived from the thickness unevenness of the adhesive layer becomes difficult to be observed. In the laminated film of the cholesteric liquid crystal layer, the liquid crystal on the air interface side of the cholesteric liquid crystal layer formed earlier is formed by forming the next cholesteric liquid crystal layer so as to be in direct contact with the surface of the cholesteric liquid crystal layer formed earlier. This is because the orientation direction of the molecules matches the orientation direction of the liquid crystal molecules below the cholesteric liquid crystal layer formed thereon, and the polarization property of the laminate of the cholesteric liquid crystal layer is improved.

[Temporary support, support, alignment layer]
The liquid crystal composition is preferably applied and layered on the surface of a support, a temporary support, or an alignment layer formed on the surface of the support or the temporary support. The support may not be peeled after the layer is formed, and the temporary support, or the temporary support and the alignment layer may be peeled after the layer is formed.
Examples of the temporary support and the support include a plastic film or a glass plate. Examples of the material of the plastic film include polyesters such as polyethylene terephthalate (PET), polycarbonate, acrylic resin, epoxy resin, polyurethane, polyamide, polyolefin, cellulose derivative, and silicone. It is also preferable that the temporary support which is a plastic film functions as a base film of a transfer sheet described later. The temporary support may function as a protective film until the half mirror is used, for example, until it is adhered to the image display device.

The alignment layer has a rubbing treatment of organic compounds such as polymers (resins such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, polyetherimide, polyamide, modified polyamide), oblique deposition of inorganic compounds, and microgrooves. It can be provided by means such as formation of a layer or accumulation of an organic compound (for example, ω-tricosanoic acid, dioctadecylmethylammonium chloride, methyl stearylate) using the Langmuir-Blodgett method (LB method). Further, an alignment layer that generates an alignment function by application of an electric field, application of a magnetic field, or light irradiation may be used.
In particular, the alignment layer made of a polymer is preferably subjected to a rubbing treatment and then a liquid crystal composition is applied to the rubbing treatment surface. The rubbing treatment can be performed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth.
The liquid crystal composition may be applied to the surface of the temporary support without providing the alignment layer, or to the surface on which the temporary support has been rubbed.
The thickness of the alignment layer is preferably 0.01 μm to 5.0 μm, and more preferably 0.05 μm to 2.0 μm.

<High Re retardation film>
The half mirror of the present invention includes a high Re retardation film. In this specification, the term “high Re phase difference film” means a phase difference film having a high front phase difference, which is distinguished from a quarter wave plate (phase difference plate). At least one high Re retardation film is included between the observation surface and the polarizing reflector. The half mirror of the present invention preferably includes one or two high Re retardation films.

The half mirror of the present invention includes the first high Re retardation film as the high Re retardation film between the observation surface and the molded resin layer. The half mirror of the present invention preferably includes only the first high Re retardation film as the high Re retardation film.
Further, when the half mirror of the present invention includes two or more high Re retardation films, a second high Re retardation film is further provided as a high Re retardation film between the molded resin layer and the polarizing reflector. It is preferable to include. That is, it is preferable that high Re retardation films are disposed on both surfaces of the molded resin layer.
In the present specification, when it is simply described as “high Re retardation film”, it corresponds to both “first high Re retardation film” and “second high Re retardation film”.

When the half mirror of the present invention includes two or more high Re retardation films, the direction of the slow axis of the two or more High Re retardation films is preferably the same. Specifically, when the half mirror of the present invention includes the first high Re retardation film and the second high Re retardation film, the direction of the slow axis of the first high Re retardation film and the second The direction of the slow axis of the high Re retardation film is preferably the same. By using the half mirror of the present invention in which the direction of the slow axis is the same, it is possible to provide an image display device in which image unevenness is more efficiently reduced.

The total front retardation of the high Re retardation film is preferably 3000 nm or more, and more preferably 5000 nm or more. The total front retardation of the high Re retardation film is preferably as large as possible, but is preferably 100000 nm or less, more preferably 50000 nm or less, still more preferably 40000 nm or less, and particularly preferably 30000 nm or less in consideration of production efficiency and thinning. .
The front retardation of the first high Re retardation film is preferably 3000 nm or more.

In addition, when the half mirror of the present invention includes two or more high Re retardation films, the front retardation of each high Re retardation film is preferably 1500 nm or more, more preferably 2000 nm or more, More preferably, it is 3000 nm or more. Further, it is preferable that the front phase differences of two or more high Re retardation films are equal to each other because manufacturing is easy. In particular, when the half mirror of the present invention includes the first high Re retardation film and the second high Re retardation film, the front retardation of the first high Re retardation film and the second high Re retardation film Are preferably equal.

As described above, the molded resin layer tends to have non-uniform birefringence. When a half mirror is used for a mirror with an image display function, the light for forming an image is transmitted through the molding resin layer, and therefore the image is observed through polarized sunglasses under the influence of the non-uniform birefringence described above. Then, light and dark unevenness and color unevenness occur. Similarly, since the mirror reflection image is also observed by the light that has passed through the molding resin layer twice, it is affected by the above-mentioned non-uniform birefringence, and when the image is observed through polarized sunglasses, light and dark unevenness or color unevenness occurs. Cheap.

Further, it is known that tempered glass (for example, tempered glass which is not a laminated glass) used for vehicle window glass, particularly rear glass, has a birefringence distribution. For this reason, it is considered that light and dark unevenness or color unevenness occurs in the mirror reflection image based on the light that passes through the rear glass of the vehicle and enters the front surface of the mirror with an image display function. In other words, when a polarized component with a distribution is generated in the light incident on the front surface of the mirror with the image display function due to the birefringence distribution, the reflected light on the front surface (outermost surface) of the mirror with the image display function and the selective reflection on the circularly polarized reflective layer It is considered that the difference in intensity of reflected light occurs due to interference with light, and the above-described brightness / darkness unevenness or color unevenness can occur.

Since the high Re retardation film can make the polarized light non-polarized in a pseudo manner, it is possible to eliminate light and dark unevenness and color unevenness.
The front phase difference that can make the polarized light pseudo-non-polarized is described in paragraphs 0022 to 0033 of JP-A-2005-321544. The specific numerical value of the front phase difference can be determined according to the molded resin layer and, when used as a mirror with a vehicle image display function described later, according to the molded resin layer and the vehicle.

Examples of the high Re retardation film include a birefringent material such as a plastic film and a quartz plate. Examples of the plastic film include polyester films such as polyethylene terephthalate (PET), polycarbonate films, polyacetal films, polyarylate films, and the like. JP-A-2013-257579, JP-A-2015-102636, and the like can be referred to for a retardation film having a high retardation including PET. Commercial products such as optical Cosmo Shine (registered trademark) super birefringence type (Toyobo) may be used.

In general, plastic films with high phase difference are melt extruded and cast on a drum or the like to form a film, which is heated and stretched uniaxially or biaxially 2 to 5 times. It can be formed by stretching at a magnification. In order to promote crystallization and increase the strength of the film, a heat treatment called “heat setting” may be performed at a temperature exceeding the stretching temperature after stretching.

A high Re retardation film may be produced by laminating a plurality of films having a retardation. Other layers such as an adhesive layer may be included between the films having a plurality of retardations.
The thickness of the high Re retardation film is preferably 1.0 μm to 10,000 μm, more preferably 10 μm to 1000 μm, and even more preferably 20 μm to 200 μm.

<Optical function layer>
The half mirror of the present invention may include an optical function layer. In the half mirror of the present invention, the optical functional layer is preferably provided so that the optical functional layer, the first high Re retardation film, the molded resin layer, and the reflective polarizing plate are in this order.
In the half mirror of the present invention, an optical functional layer that is transparent in the visible light region is used.
Examples of the optical functional layer include a hard coat layer, an antiglare layer, an antireflection layer, and an antistatic layer.
The optical functional layer is preferably a cured layer of a polymerizable composition provided on the first high Re retardation film. The optical functional layer is preferably provided on the molded resin layer after being provided on the first high Re retardation film and then being integrated with the first high Re retardation film.

[Hard coat layer]
The hard coat layer may be included as the outermost layer of the half mirror, and another layer may be provided outside the hard coat layer.
In this specification, the hard coat layer refers to a layer that, when formed, increases the pencil hardness of the half mirror surface. Specifically, it is a layer having a pencil hardness (JIS K5400) of H or higher after the hard coat layer lamination. The pencil hardness after laminating the hard coat layer is preferably 2H or more, and more preferably 3H or more. The thickness of the hard coat layer is preferably 0.1 μm to 100 μm, more preferably 1.0 μm to 70 μm, and further preferably 2.0 μm to 50 μm.
The hard coat layer may also serve as an antireflection layer or an antistatic layer.

Specific examples of the hard coat layer include a layer formed from a composition containing an ultraviolet curable polymerizable compound. The composition may contain other components such as particles. As the ultraviolet curable polymerizable compound, (meth) acrylate is preferable. As for the material and the production method of the hard coat layer, reference can be made to JP-A-2016-071085, JP-A-2012-168295, JP-A-2011-225846, and the like.

[Anti-glare layer]
The antiglare layer is a layer for imparting antiglare properties based on surface scattering. The antiglare layer may be included as the outermost layer of the half mirror, and another layer may be further provided outside the antiglare layer.
The antiglare layer can be formed from a composition containing a binder resin-forming compound for the antiglare layer and particles for the antiglare layer.
With respect to the material and production method of the antiglare layer, reference can be made to the descriptions of 0101 to 0109 of JP2013-178484A, JP2016-053601A, and the like.

[Antireflection layer]
The antireflection layer is preferably included on the outermost surface of the half mirror. By providing the antireflection layer, the reflected light on the outermost surface is suppressed, and a mirror reflection image based on an image derived from the light from the polarizing reflection plate can be clearly observed. For the material and manufacturing method of the antireflection layer, the description in 0049 to 0053 of WO2015 / 050202A can be referred to.

[Antistatic layer]
The antistatic layer is preferably contained on the outermost surface of the half mirror. Regarding the material and the production method of the antistatic layer, reference can be made to the description in JP-A-2012-027191, 0020 to 0028.

<Adhesive layer>
The half mirror may include an adhesive layer for bonding the layers. The adhesive layer may be formed from an adhesive. It is preferable to include an adhesive layer between the molded resin layer and the polarizing reflector. Moreover, it is preferable that an adhesive layer is included between the first high Re retardation film and the molded resin layer. Moreover, it is preferable that an adhesive layer is included between the second high Re retardation film and the molded resin layer.
Adhesives include thermal curing type, photocuring type, reaction curing type, and pressure-sensitive adhesive type that does not require curing, from the viewpoint of curing method, and acrylate, urethane, urethane acrylate, epoxy, epoxy as materials It is possible to use compounds such as acrylate, polyolefin, modified olefin, polypropylene, ethylene vinyl alcohol, vinyl chloride, chloroprene rubber, cyanoacrylate, polyamide, polyimide, polystyrene, polyvinyl butyral, etc. it can. From the viewpoint of workability and productivity, the photocuring type is preferable as the curing method, and from the viewpoint of optical transparency and heat resistance, it is preferable to use an acrylate, urethane acrylate, epoxy acrylate, or the like material.

A pressure-sensitive adhesive type adhesive layer that does not require curing can be formed using a sheet-like commercially available adhesive layer. You may form using what is called a highly transparent adhesive transfer tape (OCA tape). As the highly transparent adhesive transfer tape, a commercially available product for an image display device, particularly a commercially available product for the image display unit surface of the image display device may be used. Examples of commercially available products include PANAC Corporation pressure-sensitive adhesive sheets (PD-S1 and the like), MHI Series MHM series pressure-sensitive adhesive sheets, and the like.
For example, adhesion between the molded resin layer and the high Re retardation film can be performed by a pressure-sensitive adhesive type adhesive layer that does not require curing.

<Thermoplastic weld layer>
The half mirror may include a thermoplastic weld layer. The thermoplastic weld layer is used for adhesion between the layers. The thermoplastic weld layer is melted by heating and then cooled to adhere the layers. The thermoplastic weld layer is preferably used for adhesion between the molded resin layer and another layer, and the thermoplastic weld layer and the molded resin layer are preferably in direct contact with each other. The thermoplastic welding layer is used when a high Re phase difference film or a polarizing reflector is provided on one surface of the molded resin layer at the same time as the production of the molded resin layer by injection molding, as will be described later. It is preferred that The molded resin layer and the thermoplastic weld layer may form a mixed layer in which both components are mixed. A mixed layer may be formed between the molded resin layer and the thermoplastic weld layer. It is preferable to include a thermoplastic weld layer between the molded resin layer and the polarizing reflector. Moreover, it is preferable that a thermoplastic weld layer is included between the first high Re retardation film and the molded resin layer. Moreover, it is preferable that a thermoplastic weld layer is included between the second high Re retardation film and the molded resin layer.

The thermoplastic weld layer contains a thermoplastic resin. Examples of thermoplastic resins include vinyl chloride resin, vinyl acetate resin, copolymer resin of vinyl chloride and vinyl acetate, copolymer resin of ethylene and vinyl acetate, copolymer resin of isobutene and maleic anhydride, (meta ) Acrylic resin, (meth) acrylic copolymer resin, copolymer resin of styrene and butadiene, urethane resin, polyester resin, epoxy resin, silicone resin, modified silicone resin, rosin resin, polyvinyl acetal resin, chloroprene rubber, nitrile rubber, A nitrile resin etc. are mentioned.

The thickness of the thermoplastic weld layer may be 0.1 μm to 100 μm, preferably 0.5 μm to 30 μm, and more preferably 1.0 μm to 8.0 μm. By setting the thickness of the thermoplastic weld layer to 1.0 μm or more, sufficient adhesion with the substrate is ensured. Moreover, when the thickness of the thermoplastic weld layer is 8.0 μm or less, the surface roughness can be easily suppressed and a mirror-like shape can be easily obtained.

The thermoplastic welding layer can be formed by applying a coating liquid containing a thermoplastic resin to the surface of a polarizing reflection layer or a release sheet. Solvents for coating solutions include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane, cyclohexane), alkyl halides (Eg, chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane), alkyl alcohols (Eg, methanol, ethanol, propanol). Two or more kinds of solvents may be mixed and used. Among the above, alkyl halides, esters, ketones and mixed solvents thereof are preferable.
As the coating solution for forming the thermoplastic weld layer, a commercially available composition as it is as a heat sealant, or a solution dissolved in a solvent or a solution diluted with a solvent can be used.

<< Method of manufacturing half mirror >>
The half mirror of the present invention may be manufactured by adhering each layer using an adhesive layer, and at the same time as manufacturing of a molded resin layer by injection molding or the like, a high Re retardation film or a polarizing reflector is formed as a molded resin layer. It may be produced by providing on one of the surfaces and further bonding another layer to the surface using an adhesive layer.

A half mirror including only the first high Re retardation film as the high Re retardation film can be obtained, for example, by any of the following procedures.
Adhering a polarizing reflector on one main surface side of the molded resin layer and a first high Re retardation film on the other main surface side using an adhesive layer; one of the molded resin layers simultaneously with the production of the molded resin layer A polarizing reflector is provided on the main surface side of the first, and the first high Re retardation film is adhered to the other main surface side using an adhesive layer; one main surface side of the molded resin layer simultaneously with the production of the molded resin layer The first high-Re retardation film is provided on the other main surface, and the polarizing reflector is adhered to the other main surface side by using an adhesive layer; The first high Re retardation film is provided on the other main surface side.

Moreover, the half mirror including the first high Re phase difference film and the second high Re phase difference film as the high Re phase difference film can be obtained by any of the following procedures, for example.
A first high Re phase difference film is adhered to one main surface side of the molded resin layer, and a second high Re phase difference film is adhered to the other main surface side using an adhesive layer, and further, a second high Re level is obtained. A polarizing reflector is adhered to the surface side of the retardation film on which the molded resin layer is not adhered by using an adhesive layer; simultaneously with the production of the molded resin layer, a second high Re phase difference is formed on one main surface side of the molded resin layer. A film is provided and adhered to the second high Re retardation film side of the obtained molded body using an adhesive layer. Thereafter, a first high Re retardation film is adhered to the other main surface side of the molded resin layer using an adhesive layer; simultaneously with the production of the molded resin layer, the first high Re film is formed on one main surface side of the molded resin layer. An Re retardation film is provided, and a polarizing reflector and a second high Re retardation film are adhered in this order using an adhesive layer on the other main surface side; one of the molded resin layers simultaneously with the production of the molded resin layer A first high-Re phase difference film is provided on the main surface side, and a second high-Re phase difference film is provided on the other main surface side, and then bonded to the second high-Re phase difference film side of the obtained molded body. Adhere using layers.

<Injection molding>
The molded resin layer is preferably manufactured by injection molding. Injection molding is a method in which a resin is heated and melted, and then the molten resin is injected into a mold under pressure and solidified or cured to obtain a molded product. The inside of the mold means a space formed by the mold. Usually, the space only needs to be formed by two molds, a male mold and a female mold.

The injection speed when the molten resin is pressure-injected and filled into the mold is preferably 1 mm / second to 50 mm / second, and more preferably 5 mm / second to 30 mm / second.
Injection molding is performed by cooling the molten resin after it is heated and pressurized in the mold.
The heating temperature (mold temperature: surface temperature of the mold inner surface) may be 50 ° C. to 150 ° C., preferably 80 ° C. to 130 ° C. By setting the temperature range to 50 ° C. to 150 ° C., it is possible to suppress the occurrence of sink marks, burrs, flow marks, etc. when the molten resin is injected into the mold under pressure, and the molded resin layer has a stable dimension. Can be obtained. The pressurization may be from 0.01 MPa to 1.0 MPa, preferably from 0.05 MPa to 0.5 MPa, more preferably from 0.1 MPa to 0.3 MPa. The heating and pressurizing time is preferably 1 to 300 seconds, more preferably 10 to 120 seconds.

Cooling is preferably performed at room temperature or lower, specifically 10 ° C. to 30 ° C. It is preferable to pressurize before cooling. Furthermore, it is preferable that the pressurized state is maintained during cooling. In general, when the mold temperature is raised, the time until cooling becomes longer, which causes a problem that the molding cycle becomes longer. Therefore, it is preferable to cool the inner surface of the mold in a short time. The inner surface of the mold is preferably cooled at 1 ° C. to 100 ° C./second from the viewpoint of scratch resistance of the molded resin layer. The cooling rate of the inner surface of the mold is more preferably 30 ° C. to 90 ° C./second, and further preferably 40 ° C. to 80 ° C./second.
Injection molding can be performed by an injection molding machine. The injection molding machine may have an injection mechanism, a temperature control mechanism, a mold clamping mechanism, and the like in addition to the mold or the part where the mold is installed.

[Mold]
The mold is usually a set of two, and the space is formed by clamping the two. Any one of the two plates may be a fixed platen and the other may be a movable platen. One of them may be a female mold and the other may be a male mold. The female die may be a fixed platen or the male die may be a fixed platen, and the female die is preferably a fixed platen.

<In-mold molding or insert molding>
Simultaneously with the production of the molded resin layer, at least one of the polarizing reflector, the first high Re retardation film, and the second high Re retardation film (hereinafter referred to as “polarizing reflector or high Re retardation film”). In some cases, a method generally known as in-mold molding or insert molding can be used. Which is used is not particularly limited, and it is preferable that the polarizing reflector is provided by in-mold molding, and the high Re retardation film is provided by insert molding.

In in-mold molding, when injection molding is performed, a state in which a molding sheet including a polarizing reflector or a high Re retardation film and a base film is sandwiched between molds, for example, a molding sheet is a two-sheet mold. In a state of being sandwiched between the molds, a polarizing reflector or a high Re retardation film is adhered to the surface of the injection molded product in the mold simultaneously with the injection molding. The molten resin is injected into the mold during the injection molding, and the base film, the polarizing reflector or the high Re retardation film, and the molten resin may be arranged in this order. When a molding sheet having a thermoplastic weld layer is used, the thermoplastic weld layer and the molten resin such as a base film, a polarizing reflector, or a high Re retardation film are arranged in this order. Thereafter, the base film is peeled from the obtained molded resin layer, a polarizing reflector, a high Re retardation film, and the like, and a molded body including the base film. In in-mold molding, a half mirror can be manufactured by feeding a roll-shaped molding sheet into a mold and sequentially sandwiching necessary portions of the molding sheet.

Insert molding is a state in which a molding sheet including a polarizing reflector or a high Re retardation film is sandwiched between molds when performing injection molding, for example, a state in which a molding sheet is sandwiched between two molds. At the same time as the injection molding, a polarizing reflector or a high Re retardation film is adhered to the surface of the injection molded product in the mold. When the molding sheet has a thermoplastic weld layer, the thermoplastic weld layer and the molten resin, such as a polarizing reflector or a high Re retardation film, are arranged in this order. In insert molding, substantially the entire molding sheet is part of the finished product.

When the molding sheet is sandwiched between molds, it is preferable that the molding sheet is in contact with the inner surface of the mold. The contact of the molding sheet with the inner surface of the mold only needs to be achieved on at least a part of the molding sheet, and is preferably achieved on substantially the entire area corresponding to the mold. That is, it is preferable that the corresponding area of the molding sheet is in close contact with the entire surface. Contact may be achieved simply by placing the transfer sheet on the mold, or means may be taken to achieve contact. Examples of means for achieving the contact include vacuum suction. For vacuum suction, reference can be made, for example, to JP-A-10-264201.

When other members are bonded after molding the molded resin layer, the molded body obtained by the injection molding may be removed from the mold and then bonded. When the base film is peeled from the molded body obtained by in-mold molding, the base film may be peeled before or after adhesion of the optical functional layer.

[Sheet for molding]
The molding sheet preferably includes one or more of a polarizing reflector, a first high Re retardation film, and a second high Re retardation film. The molding sheet may include a thermoplastic welding layer. Moreover, the sheet | seat for shaping | molding may contain the base film.

When the molding sheet includes a thermoplastic welding layer, the polarizing reflector or the high Re retardation film is integrated with the molding resin layer by adhering the thermoplastic welding layer of the molding sheet to the molding resin layer (molten resin). A resin mirror can be obtained. The thermoplastic weld layer is preferably in the outermost layer of the molding sheet.

The surface of the outermost layer of the molding sheet, for example, the surface of the thermoplastic welding layer, may be provided with a protective layer for protection during transportation, etc., and the protective layer is peeled off when used as a molding sheet May be used.

(Transfer sheet)
In particular, a transfer sheet can be used as a molding sheet for providing a polarizing reflector.
In the injection molding of the molded resin layer, a transfer sheet can be used for providing the polarizing reflector on the molded resin layer. The transfer sheet may be a plate or a film. The transfer sheet may be in the form of a roll.
The thickness of the transfer sheet may be 1.0 μm to 300 μm, preferably 5.0 μm to 200 μm. By setting the thickness of the transfer sheet to 1.0 μm to 300 μm, it can be formed without generating wrinkles.
The transfer sheet has an elongation at room temperature of preferably 5% to 300%, more preferably 10% to 250%, and even more preferably 20% to 200%. The tensile elongation can be measured according to a thin plastic sheet tensile test (ASTM D882).

The transfer sheet includes a polarizing reflector. The transfer sheet preferably includes a thermoplastic weld layer. The transfer sheet may include other layers such as a base film, a release layer, an orientation layer, a protective layer, and an adhesive layer. The polarizing reflector and the thermoplastic welding layer may be in direct contact with each other or there may be other layers between them.
As the transfer sheet, the polarizing reflector produced as described above can be used as it is. What has a temporary support body in the case of preparation can use a temporary support body as a base film as it is. A transfer sheet including a thermoplastic welding layer can be produced by forming a thermoplastic welding layer on a polarizing reflector, usually on the surface of the polarizing reflector. The thermoplastic welding layer is obtained by applying a coating solution containing a thermoplastic resin on the polarizing reflector and drying it, or transferring the thermoplastic welding layer from the release sheet on which the thermoplastic welding layer is formed onto the polarizing reflector. It can produce by doing.

(Base film)
The molding sheet may include a base film. In particular, the transfer sheet preferably includes a base film.
As the base film, the same material as the temporary support for applying the liquid crystal composition to form a layer can be used. A preferred example is a polyethylene terephthalate film. It is preferable that the temporary support for forming a layer by applying the liquid crystal composition is the base film of the transfer sheet as it is. The transfer sheet may include an alignment layer used at the time of forming the polarizing reflector, and when the base film is peeled off in the half mirror manufacturing method, the orientation layer may or may not be peeled off at the same time. Good.
The thickness of the base film is usually about 5.0 to 200 μm, preferably about 20 to 100 μm.

(Release layer)
The molding sheet, particularly the transfer sheet, may include a release layer. The release layer is provided on the surface of the base film, and is disposed between the base film and the polarizing reflector or the high Re retardation film. It is a layer for facilitating separation, and when the base film is peeled off, it is peeled off together with the base film.
The release layer may cover the entire surface of the base film, or may be provided on a part of the base film. Usually, it is preferable to cover the entire surface of the base film in consideration of peelability.

The release layer is made of silicone resin, fluorine resin, acrylic resin (for example, acrylic-melamine resin), polyester resin, polyolefin resin, polystyrene resin, polyurethane resin, cellulose resin, chloride resin, Vinyl-vinyl acetate copolymer resins, thermoplastic resins such as nitrified cotton, copolymers of monomers that form this thermoplastic resin, or those modified with (meth) acrylic acid or urethane alone It can be formed by using a resin composition in which two or more are mixed. Among these, acrylic resins, polyester resins, polyolefin resins, polystyrene resins, copolymers of monomers forming these resins, and those obtained by urethane modification thereof are preferable. More specifically, an acrylic-melamine resin alone, an acrylic-melamine resin-containing composition, a resin composition in which a polyester resin and a copolymer of ethylene and acrylic acid are modified with urethane, an acrylic resin And a resin composition in which an emulsion of a copolymer of styrene and acrylic is mixed. Among these, it is particularly preferable that the release layer is composed of an acrylic-melamine resin alone or a composition containing 50% by mass or more of the acrylic-melamine resin. The thickness of the release layer is usually about 0.01 to 5.0 μm, preferably about 0.05 to 3.0 μm.

<< Use of half mirror >>
The half mirror can be used for various applications depending on the optical characteristics of the polarizing reflector. Examples of applications include vehicle (on-vehicle) mirrors, optical lenses, eyewear optical members, and the like. Of these, vehicle mirrors are preferred.

<< Mirror with image display function >>
A mirror with an image display function can be manufactured using the half mirror of the present invention. The mirror with an image display function includes a half mirror and an image display device. In the mirror with an image display function, the observation surface, the molded resin layer, the polarizing reflector, and the image display device are arranged in this order. In the mirror with an image display function, the image display device and the half mirror may be in direct contact with each other, an air layer may be present therebetween, or may be directly bonded via an adhesive layer.

In the mirror with an image display function, a half mirror having the same surface area as the area of the image display unit of the image display device may be used, and the half mirror having a surface area larger or smaller than the area of the image display unit of the image display device. A mirror may be used. By selecting these relationships, it is possible to adjust the ratio and position of the surface of the image display unit with respect to the entire surface of the mirror. In the present specification, the “surface area” refers to the area of either the front surface or the back surface of a plate-like or film-like member.

When a half mirror including a quarter wavelength plate is used, in the mirror with an image display function, it is preferable that the slow axis of the quarter wavelength plate is adjusted so that the image is brightest. That is, the relationship between the polarization direction of the linearly polarized light (transmission axis) and the slow axis of the quarter-wave plate so that the linearly polarized light is transmitted best, particularly for an image display device displaying an image by linearly polarized light. Is preferably adjusted. For example, in the case of a quarter wavelength plate, it is preferable that the transmission axis and the slow axis form an angle of 45 °. The light emitted from the image display device displaying an image by linearly polarized light is circularly polarized light of either right or left sense after passing through the quarter wavelength plate. The circularly polarized light reflecting layer described later only needs to be composed of a cholesteric liquid crystal layer having a twist direction that transmits the circularly polarized light of the above-described sense.

By including a quarter-wave plate between the image display device and the circularly polarized reflection layer, it becomes possible to convert the light from the image display device into circularly polarized light and make it incident on the circularly polarized reflection layer. Therefore, the light reflected by the circularly polarized light reflection layer and returning to the image display device side can be greatly reduced, and a bright image can be displayed.

<Image display device>
The image display device is preferably an image display device that emits (emits light) linearly polarized light to form an image. The half mirror of the present invention is arranged so that the slow axis of the high Re retardation film forms an angle of 30 ° to 60 ° with the polarization direction of the linearly polarized light emitted from the image display device, thereby producing a mirror with an image display function. Thus, an image having no brightness unevenness or color unevenness can be observed even when observed through polarized sunglasses.

The image display device may be a liquid crystal display device. In addition, the half mirror of the present invention eliminates light / dark unevenness or color unevenness in an image observed through polarized sunglasses by using it in combination with an image display device having a backlight that gives a continuous emission spectrum as a backlight. be able to. A white LED (white light emitting diode) is preferable as the backlight. Here, the continuous emission spectrum means, for example, an emission spectrum in the visible light region (eg, a spectrum in the visible light region of sunlight) having no wavelength region that does not substantially emit light. Examples of the backlight that gives a continuous emission spectrum include white LEDs, and those that show a discontinuous emission spectrum having a peak at a specific wavelength in the visible light wavelength region, such as a fluorescent lamp, are not included.

The liquid crystal display device may be a transmissive type or a reflective type, and is particularly preferably a transmissive type. Liquid crystal display devices include IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, VA (Vertical Alignment) mode, ECB (Electrically Controlled Birefringence) mode, STN (Super Twisted Nematic) mode, and TN (Twisted Nematic) mode. Any liquid crystal display device such as an OCB (Optically Compensated Bend) mode may be used.

The image displayed on the image display unit of the image display device may be a still image, a moving image, or simply text information. Further, it may be a monochrome display such as black and white, a multi-color display, or a full-color display. A preferable example of the image displayed on the image display unit of the image display device is an image taken by a vehicle-mounted camera. This image is preferably a moving image.

For example, the image display device only needs to indicate the emission peak wavelength λR of red light, the emission peak wavelength λG of green light, and the emission peak wavelength λB of blue light in the emission spectrum during white display. By having such an emission peak wavelength, full-color image display is possible. λR may be any wavelength in the range of 580 nm to 700 nm, preferably in the range of 610 nm to 680 nm. λG may be any wavelength in the range of 500 nm to 580 nm, preferably in the range of 510 nm to 550 nm. λB may be any wavelength in the range of 400 nm to 500 nm, preferably in the range of 440 nm to 480 nm.

<< Manufacturing method of mirror with image display function >>
The mirror with an image display function can be manufactured by arranging the half mirror on the image display side of the image display device and integrating the image display device and the half mirror. The half mirror is arranged so that the observation surface, the molded resin layer, the polarizing reflector, and the image display device are in this order. Further, as described above, the slow axis of the first high Re retardation film of the half mirror may be arranged so as to form an angle of 30 ° to 60 ° with the polarization direction of the linearly polarized light emitted from the image display device. It is preferable to arrange them at an angle of 40 ° to 50 °. In this case, when a half mirror including the first high Re phase difference film and the second high Re phase difference film is used, the direction of the slow axis of the first high Re phase difference film and the second high Re phase difference It is preferable to use half mirrors having the same slow axis direction of the film. Since the direction of the slow axis of the first high Re retardation film and the direction of the slow axis of the second high Re retardation film are the same, image unevenness can be reduced efficiently. For example, by using those having the same slow axis direction, even if the front phase difference is about 1500 nm or more and less than 3000 nm, it is possible to reduce image unevenness. Further, when the difference between the front phase difference of the first high Re retardation film and the front phase difference of the second high Re retardation film is 3000 nm or more, the image can be obtained even if the slow axis directions of both are different. Unevenness can be reduced.

Integrating the image display device and the half mirror may be performed by connecting with a frame or a hinge or bonding. For example, a mirror with an image display function can be manufactured by adhering a half mirror to an image display surface of an image display device. Adhesion is performed so that the molded resin layer, the polarizing reflector, and the image display device are in this order. Adhesion between the image display device and the half mirror can be performed using the above-mentioned adhesive layer, and it is preferable to use a highly transparent adhesive transfer tape.

<< Use of mirror with image display function >>
The use of the mirror with an image display function is not particularly limited. For example, it can be used as a security mirror, a beauty salon or a barber mirror, and can display images such as character information, still images, and moving images. The mirror with an image display function may be a vehicle rearview mirror, and may be used as a television, a personal computer, a smartphone, or a mobile phone.

The mirror with an image display function is particularly preferably used as a vehicle rearview mirror. The mirror with an image display function may have a frame, a housing, a support arm for attaching to the vehicle body, and the like for use as a rearview mirror. Alternatively, the vehicle image display function-equipped mirror may be formed for incorporation into a room mirror. In the vehicle-mounted image display function-equipped mirror having the above shape, it is possible to specify the vertical and horizontal directions during normal use.

By curving the mirror with an image display function and making the observation surface convex, it is possible to make a wide mirror that can visually recognize the rear visual field and the like in a wide angle. Such a curved observation surface can be produced using a curved half mirror.
The curve may be in the vertical direction, the horizontal direction, or both the vertical direction and the horizontal direction. In addition, the curvature may be a curvature radius of 500 mm to 3000 mm. More preferably, it is 1000 mm to 2500 mm. The radius of curvature is the radius of the circumscribed circle when the circumscribed circle of the curved portion is assumed in the cross section.

The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following examples.

<Production of half mirror>
Half mirrors of Examples 1 to 20, Comparative Examples 1 to 4, and Reference Examples 1 to 4 were produced using the following materials and procedures as shown in Table 3.

[Preparation of polarizing reflector]
(Preparation of coating solution)
For forming the cholesteric liquid crystal layer, the coating liquid 1, the coating liquid 2, and the coating liquid 3 and the coating liquid 4 for a quarter wavelength plate were prepared with the compositions shown in Table 1 below.

Compound 2 was produced by the method described in JP-A-2005-99248.

(Preparation of circularly polarized light reflector A)
The temporary support (100 mm × 150 mm) uses a PET film (Cosmo Shine A4100, thickness: 100 μm) manufactured by Toyobo Co., Ltd., and is rubbed (rayon cloth, pressure: 0.1 kgf (0.98 N), rotation speed: 1000 rpm. , Transport speed: 10 m / min, number of times: 1 reciprocation). The coating liquid 1 was applied to the rubbed surface of the PET film using a wire bar, then dried and placed on a 30 ° C. hot plate. Subsequently, UV irradiation was performed for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd. to fix the cholesteric liquid crystal phase to obtain a cholesteric liquid crystal layer having a thickness of 3.5 μm. The same process is further repeated on the surface of the obtained layer using the coating liquid 2 and the coating liquid 3, and a circularly polarizing reflector A having three cholesteric liquid crystal layers (layer of coating liquid 2: 3.0 μm, coating liquid 3 Layer: 2.7 μm). When the transmission spectrum of the circularly polarized light reflector A was measured with a spectrophotometer (manufactured by JASCO Corporation, V-670), transmission spectra having reflection peaks at 630 nm, 540 nm, and 450 nm were obtained.

(Production of circularly polarized light reflector B (including quarter-wave plate))
The coating liquid 4 was applied to the rubbed surface of the PET film using a wire bar, then dried and placed on a 30 ° C. hot plate. Subsequently, UV irradiation was carried out for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd., and the liquid crystal phase was fixed to obtain a quarter wavelength plate having a thickness of 0.8 μm. The same process is repeated using the coating liquid 1, the coating liquid 2 and the coating liquid 3 on the surface of the obtained layer, and a circularly polarizing reflector B (coating liquid) having three cholesteric liquid crystal layers on a quarter-wave plate. 1 layer: 3.5 μm, coating solution 2 layer: 3.0 μm, coating solution 3 layer: 2.7 μm). When the transmission spectrum of the circularly polarizing reflector B was measured with V-670, transmission spectra having reflection peaks at 630 nm, 540 nm, and 450 nm were obtained.

(Production of linearly polarized light reflector)
A linearly polarized light reflecting plate was produced based on the method described in JP-T-9-506837. 2,6-polyethylene naphthalate (PEN) and naphthalate 70 / terephthalate 30 copolyester (coPEN) were synthesized in a standard polyester resin synthesis kettle using ethylene glycol as the diol. A single layer film of PEN and coPEN was extruded and then stretched at a stretch ratio of 5: 1 at about 150 ° C. It was confirmed that the refractive index of PEN with respect to the orientation axis was about 1.88, the refractive index with respect to the transverse axis was 1.64, and the refractive index of the coPEN film was about 1.64.
Then, the thickness of the alternating layer of PEN and coPEN was formed in the film thickness shown in Table 2 (1) by co-extrusion using a 50 slot supply block supplied with a standard extrusion die. By repeating the above, the PEN and coPEN layers having the thicknesses shown in Table 2 (2) to (5) were formed in order, and the formation of the layers (1) to (5) was further repeated to measure 50 layers each. 250 layers were laminated. Thereafter, the stretched film was thermally cured at about 230 ° C. for 30 seconds in an air oven to obtain a linearly polarized light reflector.

[Preparation of quarter wave plate with temporary support]
The coating solution 4 was applied to a rubbed surface of a PET film using a wire bar, then dried and placed on a 30 ° C. hot plate. Next, UV irradiation was performed for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd., the liquid crystal phase was fixed, and a quarter-wave plate with a temporary support having a thickness of 0.8 μm. Got.

[Production of light-transmitting substrate (high Re retardation film)]
PET resin pellets having an intrinsic viscosity of 0.62 dl / g were dried under reduced pressure at 135 ° C. for 6 hours (1 Torr (133 Pa)), then supplied to an extruder and dissolved at 285 ° C. This polymer is filtered with a filter material of stainless sintered body (nominal filtration accuracy 10 μm particles 95% cut), extruded into a sheet form from the die, and then applied to a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method. It was wound and solidified by cooling to make an unstretched film.
The unstretched film was guided to a tenter stretching machine, and the end of the film was guided by a clip while being guided by a clip, and stretched in the width direction. Next, while maintaining the width stretched in the width direction, it was processed at a temperature of 225 ° C. for 30 seconds, and further subjected to a relaxation treatment of 3% in the width direction, and uniaxially oriented light having a front phase difference shown in Table 3 A permeable substrate was obtained. The front phase difference was measured using an AxoScan manufactured by Axometrics.

[Production of optical functional layer]
(Hard coat layer: HC)
DPHA (manufactured by Nippon Kayaku Co., Ltd.): 50 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.): 2.0 parts by mass Methyl ethyl ketone: 50 parts by mass Using the wire bar, a light transmission with a front phase difference of 8000 nm is used. After coating on the substrate, it was dried and placed on a 30 ° C. hot plate. Subsequently, UV irradiation was performed for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd. to form a hard coat layer having a thickness of 5.0 μm.

(Anti-glare layer: AG)
DPHA (manufactured by Nippon Kayaku Co., Ltd.): 50 parts by mass SX-350 (average particle size 3.5 μm, refractive index 1.55, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion, Polytron disperser 20 at 10,000 rpm Use after dispersion): 10 parts by weight Irgacure 184 (BASF Japan Ltd.): 2.0 parts by weight Toluene: 40 parts by weight The above coating solution is applied onto a light-transmitting substrate having a front phase difference of 8000 nm using a wire bar. After coating, it was dried and placed on a 30 ° C. hot plate. Subsequently, UV irradiation was performed for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd. to form an antiglare layer having a thickness of 5 μm.

(Antireflection layer: AR)
PETA (trade name PET-30): (Nippon Kayaku Co., Ltd.): 50 parts by mass KE-P30 (Nippon Shokubai Co., Ltd. amorphous silica particle seahoster, average primary particle size 300 nm): 10 parts by mass Irgacure 184 (BASF Japan shares) (Made by company): 2.0 parts by mass Butyl acetate: 50 parts by mass The above coating solution was applied on a light-transmitting substrate having a front phase difference of 8000 nm using a wire bar, and then dried and placed on a hot plate at 30 ° C. placed. Subsequently, UV irradiation was performed for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd. to form an antireflection layer having a thickness of 5.0 μm.

(Antistatic layer: AS)
Ion conductive compound (conductive polymer) IP-15 described in Japanese Patent No. 5674729: IP-15: 5 parts by mass A-TMMT (Shin Nakamura Chemical Co., Ltd.): 92 parts by mass 1-butanol: 10 parts by mass Methyl ethyl ketone: 90 parts by mass Part The coating solution was applied onto a light-transmitting substrate using a wire bar, dried, and placed on a 30 ° C. hot plate. Subsequently, UV irradiation was carried out for 6 seconds with an electrodeless lamp “D bulb” (60 mW / cm ² ) manufactured by Fusion UV Systems Co., Ltd., and the cholesteric liquid crystal phase was fixed to form an antistatic layer having a thickness of 5.0 μm.

<Production of Half Mirrors of Examples 1 to 6, 9, 10, Comparative Examples 1 and 2 and Reference Examples 1 to 3> (Single In Mold)
A heat sealant A-100 (made by DIC) is applied to the surface of the cholesteric liquid crystal layer of the circularly polarizing reflector B using a wire bar, and then dried to form a 3.0 μm thermoplastic weld layer. Got.

金 A mold comprising a combination of a concave mold and a convex mold was prepared as a mold for producing a flat plate. On the concave mold, the temporary support (base film) of the transfer sheet was arranged so as to contact the inner surface of the mold, and vacuum transfer was performed to bring the transfer sheet into contact with the bottom surface of the concave mold. A convex mold is combined with this concave mold, the mold is closed, and a molten resin made of PC (polycarbonate, Iupilon S3000) is brought into contact with the surface of the transfer sheet on the thermoplastic welding layer side in the formed space. Then, it was poured into a mold and molded (mold temperature 90 ° C., resin temperature: 300 ° C., pressure 100 MPa, time 30 seconds). The molded body obtained by cooling to room temperature and opening the mold was taken out. The temporary support was peeled off to obtain a molded body. In the obtained molded body, the molded resin layer was a flat plate of 150 mm × 100 mm × 3.0 mm.

At this time, the front phase difference distribution of the molded resin layer was adjusted by changing the injection speed and the cooling speed so as to take the values shown in Table 3.
In the examples, comparative examples, and reference examples shown in Tables 3 and 4, the front phase difference distribution of the molded resin layer is the front phase difference of each sample obtained by equally dividing the molded resin layer produced in the same manner. Was measured using AxoScan manufactured by Axometrics, and the difference between the maximum value and the minimum value was calculated as the front phase difference distribution.

Thereafter, an optical adhesive film PDS1 manufactured by Panac was bonded to the surface of the molded resin layer of the obtained molded body with a SEAL type precision single-wafer bonding machine SE550aa (manufactured by Climb Products), and then the same apparatus was used. Examples 1 to 6, 9, 10, Comparative Examples 1 and 2, with or without bonding a permeable substrate (first high Re retardation film: front phase difference shown in Table 3) And the half mirrors of Reference Examples 1 to 3 were obtained.

<Production of Half Mirrors of Examples 12 to 15>
Instead of the light transmissive substrate, a light transmissive substrate (first high Re retardation film: front phase difference 8000 nm) provided with the hard coat layer, antiglare layer, antireflection layer, and antistatic layer, respectively. The half mirrors of Examples 12 to 15 were produced in the same manner as the production of the half mirror of Example 1, except that (2) was used. In addition, the bonding to the adhesive film was performed so that the light-transmitting substrate side was in contact with the adhesive film.

<Production of Half Mirror of Example 11> (Single-sided in-mold / single-sided insert molding)
Heat sealant A-100 (manufactured by DIC) was applied to one side of a light-transmitting substrate (first high Re retardation film) having a front phase difference of 8000 nm using a wire bar, and then dried to heat 3.0 μm. A plastic weld layer was formed to obtain a light-transmitting substrate (molding sheet) with a thermoplastic weld layer.
A mold comprising a combination of a concave mold and a convex mold was prepared as a mold for producing a flat plate. The light transmissive substrate with the thermoplastic weld layer was disposed so that the light transmissive substrate was in contact with the inner surface of the convex mold. On the concave mold, the temporary transfer substrate (base film) of the same transfer sheet as the transfer sheet used in Example 1 is disposed so as to contact the inner surface of the mold, and vacuum transfer is performed to place the transfer sheet on the bottom surface of the concave mold. Contact. Both molds are combined and closed, and a molten resin made of PC (polycarbonate, Iupilon S3000) is injected between the light-transmitting substrate in the mold and the transfer sheet (mold temperature 90 ° C., resin temperature : 300 ° C., pressure 100 MPa, time 30 seconds). The molded body obtained by cooling to room temperature and opening the mold was taken out. The temporary support was peeled off to obtain a half mirror. The front phase difference distribution of the molded resin layer was adjusted to take the values shown in Table 3 as in Example 1.

<Production of Half Mirrors of Examples 7, 8, 16, 17, and 18>
[Production of molded resin layer]
Close the mold for producing a flat plate consisting of a combination of concave and convex molds and inject the molten resin shown in Table 3 (mold temperature 90 ° C, resin temperature: 300 ° C, pressure 100 MPa, time 30 seconds)) did. The molded resin layer (flat plate of 150 mm × 100 mm × 3 mm) obtained by cooling to room temperature and opening the mold was taken out.
In Table 3, PC of the molten resin is Iupilon S3000, acrylic is Sumipex MG5, PET is PETG K2012, and COP is ZEONEX E48R. The front phase difference distribution of the molded resin layer was adjusted to take the values shown in Table 3 as in Example 1.

An optical adhesive film PDS1 manufactured by Panac was bonded to the main surface on one side of the obtained molded resin layer using a SEAL type precision single wafer bonding machine SE550aa (manufactured by Climb Products). Subsequently, the same apparatus was used, and the circularly polarized light reflector B or the linearly polarized light reflector was bonded to the surface of the adhesive film. At this time, in the case of the circularly polarized light reflector B, the cholesteric liquid crystal layer side (the side opposite to the temporary support side) was bonded so as to contact the adhesive film, and the temporary support was peeled off. In the case of a linearly polarized light reflecting plate, it is bonded so that an arbitrary surface is in contact with the adhesive film, and the transmission axis of the linearly polarized light reflecting film and the transmission axis of the display-side polarizing plate of the image display device are matched. Pasted.

An optical adhesive film PDS1 made by Panac is pasted on the surface of the molded resin layer opposite to the circularly polarized light reflector B or the linearly polarized light reflector with a SEAL type precision single wafer pasting machine SE550aa (Crim Products), and then the same. Using the apparatus, a light-transmitting substrate (first high Re phase difference film: front phase difference 8000 nm) was bonded.

<Production of Half Mirror of Comparative Example 3>
An optical adhesive film PDS1 manufactured by Panac was bonded to the main surface of one side of the molded resin layer obtained in the same procedure as in Example 7 using a SEAL precision sheet-fed bonding machine SE550aa (manufactured by Climb Products). Subsequently, the same apparatus was used, and the optical adhesive film and the quarter wavelength plate with a temporary support were bonded. At this time, it bonded so that the quarter wavelength plate side (opposite side to a temporary support body side) might contact an adhesive film, and the temporary support body was peeled after that.
After that, the optical adhesive film PDS1 made by Panac is pasted on the surface of the molding resin layer opposite to the surface on which the quarter-wave plate is provided, using a SEAL type precision single wafer laminating machine SE550aa (manufactured by Climb Products). Then, using the same apparatus, a light transmissive substrate (first high Re retardation film: front retardation 8000 nm) was bonded.
The SEAL system precision sheet bonding machine SE550aa (manufactured by Climb Products) is used to bond the optical adhesive film PDS1 manufactured by Panac on the surface of the light-transmitting substrate, and then the same apparatus is used. A circularly polarized light reflector A was bonded to the substrate. At this time, it bonded so that the cholesteric liquid crystal layer side (opposite side to a temporary support body side) might contact an adhesive film, and the temporary support body was peeled after that.

<Production of Half Mirror of Comparative Example 4>
An optical adhesive film PDS1 manufactured by Panac was bonded to the main surface of one side of the molded resin layer obtained in the same procedure as in Example 7 using a SEAL precision sheet-fed bonding machine SE550aa (manufactured by Climb Products). Next, using the same apparatus, an optical adhesive film and a light-transmitting substrate (first high Re retardation film: front retardation 8000 nm) were bonded. An optical adhesive film PDS1 manufactured by Panac Co., Ltd. was bonded to the surface of this light-transmitting substrate with a SEAL-type precision single-wafer bonding machine SE550aa (manufactured by Crime Products Co., Ltd.). A quarter-wave plate with a support was bonded. At this time, it bonded so that the quarter wavelength plate side (opposite side to a temporary support body side) might contact an adhesive film, and the temporary support body was peeled after that. SEAL type precision single wafer laminating machine SE550aa (manufactured by Climb Products) is used on this release surface, optical adhesive film PDS1 made by Panac is used, and then the same device is used to apply circularly polarizing reflector A. did. At this time, it bonded so that the cholesteric liquid crystal layer side (opposite side to a temporary support body side) might contact an adhesive film, and the temporary support body was peeled after that.

<Production of Half Mirror of Example 19 and Reference Example 4>
A heat sealant A-100 (made by DIC) was applied to the surface of a light-transmitting substrate (second high Re retardation film: front retardation 4000 nm) using a wire bar, and then dried to heat 3.0 μm. A plastic welding layer was formed to obtain a molding sheet.
A mold comprising a combination of a concave mold and a convex mold was prepared as a mold for producing a flat plate. On the concave mold, the light-transmitting substrate of the molding sheet was arranged in such a direction as to contact the inner surface of the mold, and vacuum suction was performed to bring the molding sheet into contact with the bottom surface of the concave mold. A convex mold is combined with this concave mold, the mold is closed, and a molten resin made of PC (polycarbonate, Iupilon S3000) is brought into contact with the surface of the transfer sheet on the thermoplastic welding layer side in the formed space. Then, it was poured into a mold and molded (mold temperature 90 ° C., resin temperature: 300 ° C., pressure 100 MPa, time 30 seconds). The molded body obtained by cooling to room temperature and opening the mold was taken out. The molded resin layer in the obtained molded body was a flat plate of 150 mm × 100 mm × 3.0 mm.
The front phase difference distribution of the molded resin layer at this time was prepared by adjusting the injection speed and the cooling speed so as to take the values shown in the table.

Thereafter, an optical adhesive film PDS1 made by Panac was pasted on the light-transmitting base material (second high Re retardation film) with a SEAL-type precision single-wafer laminating machine SE550aa (Crim Products), and then the same. Using the apparatus, the circularly polarized light reflector B was bonded. At this time, in the case of the circularly polarized light reflector B, the cholesteric liquid crystal layer side (the side opposite to the temporary support side) was bonded so as to contact the adhesive film, and the temporary support was peeled off.
After that, the optical adhesive film PDS1 made by Panac is pasted on the surface of the molded resin layer opposite to the circularly polarizing reflector B using a SEAL precision single-wafer laminating machine SE550aa (manufactured by Climb Products), and then the same apparatus is used. The direction of the slow axis of the light transmissive substrate (first high Re phase difference film, front phase difference 4000 nm) is the angle shown in Table 4 with respect to the direction of the slow axis of the second high Re phase difference film. The half mirrors of Example 19 and Reference Example 4 were obtained.

<Production of Half Mirror of Example 20>
As in Example 7, the mold for producing a flat plate comprising a combination of a concave mold and a convex mold was closed, and the molten resin shown in Table 4 was injected and molded (mold temperature 90 ° C., resin temperature: 300 ° C., pressure 100 MPa. , Time 30 seconds)). The molded resin layer (flat plate of 150 mm × 100 mm × 3 mm) obtained by cooling to room temperature and opening the mold was taken out.
In Table 4, the molten resin PC is Iupilon S3000. The front phase difference distribution of the molded resin layer was adjusted to take the values shown in the table in the same manner as in Example 1.

An optical adhesive film PDS1 manufactured by Panac was bonded to the main surface on one side of the obtained molded resin layer using a SEAL type precision single wafer bonding machine SE550aa (manufactured by Climb Products). Next, using the same device, a light-transmitting substrate (second high Re retardation film, front retardation 4000 nm) is bonded to the surface of the adhesive film, and SEAL type precision single wafer bonding machine SE550aa (Climb) An optical adhesive film PDS1 manufactured by Panac Co., Ltd. was pasted with a product manufactured by Products Co., Ltd., and then the circularly polarizing reflector B was pasted using the same apparatus. At this time, in the case of the circularly polarized light reflector B, the cholesteric liquid crystal layer side (the side opposite to the temporary support side) was bonded so as to contact the adhesive film, and the temporary support was peeled off.

An optical adhesive film PDS1 manufactured by Panac was bonded to the surface of the molded resin layer opposite to the circularly polarizing reflector B using a SEAL type precision single wafer bonding machine SE550aa (manufactured by Climb Products), and then the same apparatus was used. The light transmissive substrate (first high Re phase difference film, front phase difference 4000 nm) is set so that the slow axis direction forms an angle of 0 ° with the slow axis direction of the second high Re phase difference film. The half mirror of Example 20 was obtained.

<Evaluation of half mirror>
[Evaluation of uneven color of image]
A half mirror was arranged on the image display surface of the following image display device so as to be parallel to the image display surface, and a white image was displayed.
(Image display device)
LCD monitor white LED type: (FLATORON E2260V (manufactured by LG Electronics Japan))
Fluorescent lamp type: (FLATORON W2240V (manufactured by LG Electronics Japan))

Tables 3 and 4 show the angles formed by the slow axis of the light-transmitting substrate and the polarization axis of the viewing-side polarizer of the image display device between 0 ° and 90 ° while maintaining the above parallel state. The position was set as follows. When the white image was displayed on the image display device, the image was observed from the observation surface with polarized sunglasses, and the presence and extent of color unevenness was confirmed. Evaluation was made according to the following criteria. The results are shown in Tables 3 and 4.
None: When observed from the front, color unevenness does not occur and visibility is not a problem.
Existence: Color unevenness is observed when observed from the front.

[Evaluation of unevenness of mirror reflection image]
Table 3 shows the angles formed by the slow axis of the light-transmitting substrate and the polarization axis of the viewing-side polarizer of the image display device in the range of 0 ° to 90 °, as in the case of the color unevenness evaluation of the image. The position was set as follows. The mirror reflection image when the image display device was turned off was observed from the observation surface with polarized sunglasses, and the presence and extent of color unevenness was confirmed. Evaluation was made according to the following criteria. The results are shown in Tables 3 and 4.
None: When observed from the front, color unevenness does not occur and visibility is not a problem.
Existence: Color unevenness is observed when observed from the front.

[Linear polarization transmittance]
The linearly polarized light transmittance was measured using an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation. The transmittance for linearly polarized light was measured by placing a linearly polarizing plate on the light source side of the spectrophotometer so that the polarization transmission axis and the slow axis of the quarter wavelength plate were 45 °. The average transmittance with respect to the linearly polarized light having a wavelength of 400 nm to 700 nm of the natural light transmittance thus obtained was calculated, and 80% or more was judged good and less than 80% was judged as bad. The results are shown in Tables 3 and 4.

Claims

Including the observation surface, the molded resin layer, and the polarizing reflector in this order,
Including at least one high Re retardation film between the observation surface and the polarizing reflector, the total of the front retardation of the high Re retardation film is 3000 nm or more,
A half mirror comprising a first high Re retardation film as the high Re retardation film between the observation surface and the molding resin layer.
The half mirror according to claim 1, wherein a front phase difference distribution of the molded resin layer is 100 nm or more.
The half mirror according to claim 1 or 2, wherein a total of the front phase differences of the high Re retardation film is 5000 nm or more.
The half mirror according to any one of claims 1 to 3, wherein a front phase difference of the first high Re retardation film is 3000 nm or more.
The half mirror according to any one of claims 1 to 4, wherein only the first high Re retardation film is included as the high Re retardation film.
The half mirror according to any one of claims 1 to 4, further comprising a second high Re retardation film as the high Re retardation film between the molding resin layer and the polarizing reflector.
The half mirror according to claim 6, wherein a direction of a slow axis of the first high Re retardation film and a direction of a slow axis of the second high Re retardation film are the same.
The half mirror according to claim 6 or 7, comprising an adhesive layer or a thermoplastic welding layer between the second high Re retardation film and the molding resin layer.
The half according to any one of claims 1 to 8, wherein the molded resin layer contains one or more polymers selected from the group consisting of polycarbonate, poly (meth) acrylate, polyester, and cycloolefin polymer. mirror.
The half mirror according to any one of claims 1 to 9, wherein the polarizing reflector is a circularly polarizing reflector layer.
The half mirror according to claim 10, wherein the circularly polarized light reflection layer includes a cholesteric liquid crystal layer.
The half mirror according to claim 11, wherein the circularly polarized light reflection layer includes three or more cholesteric liquid crystal layers.
A quarter wave plate;
The half mirror according to any one of claims 10 to 12, including the molded resin layer, the polarizing reflector, and the quarter-wave plate in this order.
The half mirror according to claim 13, wherein the polarizing reflection plate and the quarter-wave plate are in direct contact with each other.
The half mirror according to any one of claims 1 to 14, further comprising an adhesive layer or a thermoplastic weld layer between the molded resin layer and the polarizing reflector.
The half mirror according to any one of claims 1 to 15, further comprising an adhesive layer or a thermoplastic welding layer between the first high Re retardation film and the molding resin layer.
A half mirror according to any one of claims 1 to 16, and an image display device,
The mirror with an image display function in which the observation surface, the molding resin layer, the polarizing reflector, and the image display device are arranged in this order.
The image display device emits linearly polarized light to form an image,
The image display device has a backlight that gives a continuous emission spectrum;
The mirror with an image display function according to claim 17, wherein a slow axis of the first high Re retardation film forms an angle of 30 ° to 60 ° with a polarization direction of the linearly polarized light.
The mirror with an image display function according to claim 18, wherein the image display device is a liquid crystal display device, and the backlight is a white LED.