JP6659994B2 - Display device - Google Patents

Description

  The present invention relates to a display device that reflects projected image light.

  2. Description of the Related Art A head-up display (hereinafter, also referred to as "HUD") is a display device for a vehicle that projects image light from an image source arranged in an instrument panel to a front window and displays various information to a driver. It is. BACKGROUND ART Conventionally, as a front window of a vehicle, laminated glass in which an intermediate layer for preventing scattering is sandwiched between a pair of glass plates has been used. When the HUD image light is projected onto the laminated glass, the image light may appear double due to refraction of the light. In order to control the refraction of light, a laminated glass having an intermediate layer having a wedge-shaped cross section has been proposed (see Patent Document 1).

The mounting angle of the front window of the vehicle differs for each vehicle type. When the intermediate layer has a wedge-shaped cross section, its thickness, wedge angle, and the like are designed according to the angle of attachment to the vehicle. However, at present, it is difficult to design the wedge shape of the intermediate layer according to the mounting angle to the vehicle, and it is also difficult to manufacture the intermediate layer so that the cross section of the intermediate layer has the designed wedge shape.
When the HUD is mounted on a vehicle, the image source is arranged in a vertically lower region in front of an optical sheet provided in a front window. However, since a large number of steering wheels, instruments, and the like for operating the vehicle are arranged in this area, it is difficult to secure an area where the image source is arranged.

Japanese Patent No. 2815693 JP 2010-78860 A

  An object of the present invention is to provide a display device which can be easily designed and manufactured, can obtain good optical performance, and has an increased degree of freedom in a region where an image source is arranged.

The present invention solves the above problem by the following means. In addition, in order to make it easy to understand, description is given with reference numerals corresponding to the embodiment of the present invention, but the present invention is not limited to this.
The first invention comprises an image source (11) for projecting image light, and an optical sheet (20) for reflecting a part of the image light projected from the image source to an observer side, wherein the optical sheet A first optical shape layer (21) in which a plurality of unit optical shapes (21a) each having a first inclined surface (21b) and a second inclined surface (21c) are arranged, and the unit optics of the first optical shape layer A second optical shape layer (23) laminated on the surface on which the shape is provided; and a second optical shape layer (23) formed on at least a part of the first inclined surface to reflect a part of incident light and transmit the other. A reflection layer (22), wherein the image source is configured such that, when the optical sheet is viewed from a thickness direction, a line segment passing through the image light emission position and the geometric center of the optical sheet is It passes through the geometric center of the optical sheet and is inclined with respect to a line parallel to the vertical direction. A display device (10), characterized in that disposed.
A second invention is the display device (10) according to the first invention, wherein the arrangement direction of the first optical shape layer (21) in the optical sheet (20) is such that the optical sheet is viewed from a thickness direction. In this case, the display device is inclined to the same side as a line segment passing through the emission position of the image light and the geometric center of the optical sheet.
A third invention is the display device (10) according to the first or second invention, wherein the first support (31) arranged on the viewer side of the optical sheet (20); A first intermediate layer (32) arranged between a support and the optical sheet; a second support (34) arranged on the optical sheet on the side opposite to a viewer; And a second intermediate layer (33) disposed between the optical sheet and the second support. The first intermediate layer and the second intermediate layer each have a layer in a range from an upper end to a lower end of the optical sheet. A display device having a uniform thickness.
A fourth invention is the display device (10) according to any one of the first to third inventions, wherein the reflection layer (22) is formed of a metal formed in a specific region of the optical sheet (20). A display device characterized by being a layer.
A fifth invention is the display device (10) according to any one of the first to third inventions, wherein the reflection layer (22) is a dielectric multilayer film. is there.

  According to the present invention, it is possible to provide a display device which is easy to design and manufacture, can obtain good optical performance, and has an increased degree of freedom in a region where an image source is arranged.

FIG. 2 is a diagram illustrating the vicinity of the driver's seat of the automobile 1 on which the display device 10 according to the first embodiment is arranged. FIG. 2 is a diagram illustrating a display device 10 according to the first embodiment. FIG. 3 is a diagram illustrating a method for manufacturing the optical sheet 20 according to the first embodiment. It is a figure explaining display 10 of a 2nd embodiment. It is a figure explaining display 10 of a 3rd embodiment. It is a figure explaining front window 2 of a 4th embodiment. It is a figure explaining front window 2 of a 5th embodiment. It is a figure explaining optical sheet 20 of a 6th embodiment. It is a figure explaining each front window 2 of a 7th, 8th, and 9th embodiment. FIG. 3 is a diagram illustrating an area where an optical sheet 20 according to the first embodiment is arranged. It is a figure explaining the field which arranges optical sheet 20 of a 3rd embodiment.

Hereinafter, an embodiment in which the display device according to the present invention is applied to a head-up display (HUD) mounted on a front window of an automobile will be described. In addition, each figure shown below including FIG. 1 is a diagram schematically shown, and the size and shape of each part are exaggerated as appropriate for easy understanding.
Numerical values such as dimensions of each member and material names and the like described in this specification are examples of the embodiment, and are not limited thereto, and may be appropriately selected and used.
In the present specification, terms that specify shapes and geometric conditions, for example, terms such as parallel and orthogonal are not only strictly meaningful, but also have a similar optical function and can be regarded as parallel or orthogonal. It also includes a state having an error of

(1st Embodiment)
FIG. 1 is a diagram illustrating the vicinity of a driver's seat of an automobile 1 in which a display device 10 according to the first embodiment is arranged. FIG. 1A is a diagram illustrating a state in which the front window 2 side (the traveling direction of the vehicle) is viewed from the driver's seat of the vehicle 1. FIG. 1B is an arrow view from a section b in FIG. 1A, and FIG. 1C is a view from an arrow c in FIG. 1A, that is, the driver's seat is viewed from above. FIG.
FIG. 2 is a diagram illustrating the display device 10 according to the first embodiment. FIG. 2A is a front view of the optical sheet 20 viewed from the driver side in the thickness direction. FIG. 2B is a diagram showing a cross section on the center line of the optical sheet 20 in the left-right direction, that is, a cross section of a part b in FIG. 2A. FIG. 2C is a view showing a cross section in a section parallel to the thickness direction (Y direction) and parallel to the arrangement direction of the unit optical shapes 21a, that is, a section c in FIG. 2A.

  In addition, in the following drawings including FIG. 2 and in the following description, in order to facilitate understanding, the vertical direction of the optical sheet is defined as the Z direction, the thickness direction is defined as the Y direction, and the horizontal direction is defined as the X direction. Here, in the vertical direction (Z direction), the −Z side is the lower side, and the + Z side is the upper side. In the thickness direction (X direction), the −Y side is the back side, and the + Y side is the driver side. In the left-right direction (X direction), the −X side is the left side, and the + X side is the right side.

As shown in FIG. 1, the automobile 1 of this embodiment has a driver's seat on the right side of a front window 2 when viewed from the inside of the vehicle, and an interior panel 3 below the front window 2. The vehicle 1 is provided with a display device 10. An optical sheet 20 (to be described later) constituting the display device 10 is disposed on the right side of the surface inside the front window 2 (inside the vehicle).
The interior panel 3 is a decorative panel disposed below the front window 2, and a steering wheel 4 serving as a control stick of the vehicle and instruments 5 such as a speedometer of the vehicle are disposed on the right side thereof. Further, on the interior panel 3, an image source 11 (to be described later) constituting the display device 10 and the like are arranged.

The display device 10 is a device capable of displaying the speed of the automobile 1, the state of the turn signal, and the like on the driver's line of sight, that is, a so-called head-up display device. The state such as the speed of the vehicle 1 can be grasped without warping.
The display device 10 includes an image source 11, a projection optical system 12, an optical sheet 20, and the like. The display device 10 projects image light such as speed information emitted from the image source 11 to the driver via the optical sheet 20. Specifically, the display device 10 causes the image light formed by the image source 11 to enter the optical sheet 20 via the projection optical system 12, and reflects the image information to the driver side. In the present embodiment, the display device 10 is described as a head-up display mounted on the driver's seat of the automobile 1, but is not limited thereto, and is mounted on another vehicle, for example, an aircraft, a railway, or the like. Head-up display.

The image source 11 is a display that displays image light, and for example, a transmissive liquid crystal display device, a reflective liquid crystal display device, an organic EL, or the like can be used. As shown in FIG. 1, the image source 11 of the present embodiment is configured such that the projection optical system 12 is located below the optical sheet 20 and to the left of the optical sheet 20 when viewing the front window 2 from the driver's seat. It is arranged with.
Specifically, as shown in FIG. 2A, the image source 11 is configured such that, when viewed from the thickness direction (Y direction) of the optical sheet 20, the emission position 11a of the image light L of the image source 11 and the optical sheet The line connecting the 20 geometric centers C1 passes through the geometric center C1 of the optical sheet 20 and is inclined to the right with respect to a line parallel to the vertical direction (Z direction). . Thereby, the display device 10 can arrange the image source 11 avoiding the periphery of the steering wheel 4 and the instruments 5 in the driver's seat, and improve the degree of freedom of the arrangement position of the image source 11 in the driver's seat. it can. Here, the emission position 11a of the image source 11 is a position that is the geometric center of the surface of the image source 11 from which the image light L is emitted.
The projection optical system 12 is an optical system that is disposed at an emission position 11a of the image source 11, and is configured by a plurality of lens groups that project image light emitted from the image source 11.

  The optical sheet 20 is a layer having light transmissivity, and is attached to the right side (in front of the driver's seat) of the surface inside the front window 2 (inside the vehicle), as shown in FIG. As shown in FIG. 2B, the optical sheet 20 includes an optical shape layer (first optical shape layer) 21, a reflection layer (metal layer) 22, and a back layer (second optical shape) in order from the driver side (+ Y side). (Shape layer) 23 are laminated. The optical sheet 20 transmits a part of the light in the traveling direction of the automobile viewed from the driver's seat through the front window 2 from the back side of the optical sheet 20 to the driver side from the viewpoint of not obstructing the driver's view. It has a so-called see-through function that allows light and video light to be viewed in an overlapping manner.

The optical shape layer 21 is a layer having light transmissivity. As shown in FIG. 2A, a linear Fresnel lens shape in which a plurality of unit optical shapes 21a are arranged in parallel is formed on the back side (−Y side). The surface has.
As shown in FIG. 2C, the unit optical shape 21a is parallel to a direction (thickness direction, Y direction) orthogonal to the sheet surface (XZ plane) and parallel to the arrangement direction R1 of the unit optical shapes 21a. The cross-sectional shape in the cross section is a substantially triangular shape.
The unit optical shape 21a is convex on the back side and includes an incident surface (first inclined surface) 21b on which image light is directly incident, and an opposing surface (second inclined surface) 21c facing the incident surface 21b. I have. In the present embodiment, the unit optical shape 21a is such that the incident surface 21b is located above the opposing surface 21c (+ Z side) with the top t interposed therebetween.
The unit optical shape 21a extends in the sheet plane (XZ plane) of the optical sheet 20 in a direction orthogonal to the arrangement direction R1.

  As shown in FIG. 2A, the arrangement direction R1 of the unit optical shapes 21a is such that, when the optical sheet 20 is viewed from the thickness direction (Y direction), the emission position 11a of the image light L of the image source 11 and the optical sheet It is inclined to the same side as the line segment passing through the 20 geometric centers C1, that is, to the right (+ X side) in the present embodiment. With such a configuration, the optical sheet 20 can efficiently reflect the image light projected from the image source 11 disposed diagonally below and to the left of the optical sheet 20 toward the driver.

Here, the angle formed by the plane of incidence 21b of the unit optical shape 21a and a plane parallel to the sheet plane (XZ plane) is α. The angle formed by the facing surface 21c and a surface parallel to the sheet surface is β (β> α). Furthermore, the arrangement pitch of the unit optical shapes 21a is P, and the height of the unit optical shapes 21a (the dimension from the top t in the thickness direction to the portion v that is the valley between the unit optical shapes 21a) is h.
The arrangement pitch P is desirably formed in the range of 100 to 2000 μm from the viewpoint of suppressing a line of stripes caused by the unit optical shape 21 a from being visually recognized. Preferably, the angle α is in the range of 10 to 50 °, the angle β is in the range of 70 to 110 °, the height h is in the range of 10 to 1500 μm, the angle α is 20 to 40 °, the angle β is 90 °, It is more desirable that the thickness h be formed in the range of 100 to 1000 μm.

For ease of understanding, FIG. 2 shows that the arrangement pitch P and the angles α and β of the unit optical shapes 21a are constant in the arrangement direction of the unit optical shapes 21a. In the unit optical shape 21a of the present embodiment, the arrangement pitch P, the angle β, and the like are constant, but the angle α may gradually increase as the distance from the image source 11 in the arrangement direction of the unit optical shape 21a. Accordingly, the height h may also vary.
The arrangement pitch P is not limited to this, and the arrangement pitch P may be a form that gradually changes along the arrangement direction of the unit optical shapes 21a. For example, the size of the image projected from the image source, the projection angle of the image source 11 (optical The angle of incidence of image light on the driver's side surface of the seat 20), the size of the image reflected on the driver's side, the refractive index of each layer, and the like can be changed as appropriate.

The optical shape layer 21 is formed of an ultraviolet curable resin such as urethane acrylate or epoxy acrylate by a UV molding method or the like. The optical shape layer 21 may be formed of another ionizing radiation curable resin such as an electron beam curable resin. The optical shape layer 21 is made of a thermoplastic resin, a thermosetting resin, a resin obtained by combining the above-described ultraviolet-curable resin and thermosetting resin, a resin obtained by combining a thermoplastic resin and an ultraviolet-curable resin, or the like. It may be formed.
The optical shape layer 21 may be formed by a press molding method or the like according to the unit optical shape 21a formed on the back side. In the case of such an optical shape layer 21, a mode in which the optical shape layer 21 is laminated on a transparent substrate via a bonding layer or the like may be adopted.

The reflective layer 22 is a semi-transmissive reflective layer that reflects a part of the incident light and transmits the other light, that is, a so-called half mirror. The ratio between the reflectance and the transmittance of the reflective layer 22 can be set as appropriate. In addition, from the viewpoint of well reflecting the image light and sufficiently transmitting the light incident from the traveling direction side of the automobile and improving the visibility of the driver, the transmittance may be 70% or more. desirable.
The reflection layer 22 is formed of a metal having high light reflectivity, for example, aluminum, silver, nickel, or the like. In the present embodiment, the reflection layer 22 is formed by evaporating aluminum. The reflective layer 22 is not limited thereto, and may be formed by sputtering a metal having high light reflectivity, transferring a metal foil, applying a paint containing a metal thin film piece, or the like.
The reflective layer 22 of the present embodiment is formed to a thickness of about 40 to 60 ° by vapor deposition of aluminum. However, if the light transmittance can be set to the above-described preferable range, the thickness is determined according to the material and the like. Can be set freely.
In addition, the reflection layer 22 of the present embodiment is formed on the entire surface of the incident surface 21b, but is not limited thereto, and may be formed on a part of the incident surface 21b.

The rear surface layer 23 is a layer provided on the surface on the rear surface side (−Y side) of the optical shape layer 21, and is provided to make the rearmost surface of the optical sheet 20 flat. The back layer 23 is formed of a highly light-transmissive urethane acrylate resin, epoxy acrylate resin, or the like, and has a refractive index equivalent to that of the optical shape layer 21. The surface on the back side of the back layer 23 is a surface joined to the front window 2 via a joining layer (not shown), and is an incident surface of light that enters the optical sheet 20 from the back side via the front window 2. is there.
The bonding layer for bonding the optical sheet 20 to the front window 2 can be made of a light-transmitting adhesive or adhesive, such as an acrylic resin, a urethane resin, an epoxy resin, a phenol resin, or a silicone resin. Can be used.

Next, the image light L and the light G from the outside that enter the optical sheet 20 of the present embodiment will be described.
As shown in FIG. 1B, the image light L projected from the image source 11 is incident on the driver-side surface of the optical sheet 20 via the projection optical system 12. Part of the image light L incident on the optical sheet 20 is incident on the incident surface 21b of the unit optical shape 21a, and is reflected on the reflection layer 22 toward the driver. Then, a part of the light G from the outside is transmitted from the back side of the optical sheet 20 to the driver side. Therefore, the driver can see the light G from outside and the image light L in an overlapping manner. Further, another part of the light L <b> 2 of the image light L passes through the reflective layer 22, then passes through the back layer 23, and exits from the back surface (−Y side) of the optical sheet 20.

Next, an example of a method for manufacturing the optical sheet 20 of the first embodiment will be described.
FIG. 3 is a diagram illustrating a method for manufacturing the optical sheet 20 according to the first embodiment. Each drawing in FIG. 3 is a diagram showing a process until the optical sheet 20 is manufactured.
First, as shown in FIG. 3A, the optical sheet 20 is formed using a mold (not shown) provided with a concave / convex shape corresponding to the unit optical shape 21a (incident surface 21b, facing surface 21c). The optical shape layer 21 to be formed is formed by a UV molding method or the like.
Next, as shown in FIG. 3B, on the incident surface 21b of the unit optical shape 21a, a deposition metal (aluminum) AL is deposited by a vacuum deposition method to form the reflection layer 22. In this embodiment, the aluminum is heated and melted in a vacuum state using a vacuum deposition apparatus, and the aluminum is deposited on the incident surface 21 b of the optical shape layer 21.

  Subsequently, as shown in FIG. 3C, the surface of the optical shape layer 21 on which the unit optical shape 21a is formed is filled with a resin constituting the back layer 23, and a mold having a flat surface is formed. Press. Then, the back layer 23 can be formed by releasing the mold after curing. Through the above process, the optical sheet 20 in which the optical shape layer 21, the reflective layer 22, and the back layer 23 are sequentially laminated is completed.

  As described above, according to the display device 10 of the first embodiment, of the image light L projected from the image source 11, most of the light reaching the driver is the unit optical shape 21a of the optical sheet 20. It becomes reflected light. Therefore, in the display device 10, the image light does not look double due to the refraction of light as in the case where the HUD image light is projected on the conventional laminated glass, and a clearer image is provided to the driver. Can be displayed.

  In the unit optical shape 21a of the optical sheet 20, the angle α between the incident surface 21b and the surface parallel to the sheet surface (XZ surface) and the angle β between the facing surface 21c and the surface parallel to the sheet surface are determined by the optical sheet 20. Can be easily designed in accordance with the inclination angle when the front window 2 with the label is attached to the automobile 1, the projection angle of the image light from the image source 2, and the like. The optical shape layer 21 can be easily manufactured as designed by using a method such as a roll-to-roll method.

Further, when viewed from the thickness direction (Y direction) of the optical sheet 20, a line segment connecting the emission position 11 a of the image light L of the image source 11 and the geometric center C <b> 1 of the optical sheet 20 is a line segment of the optical sheet 20. It is inclined to the right with respect to a line passing through the geometric center C1 and parallel to the vertical direction (Z direction). Thereby, the display device 10 of the present embodiment arranges the image source 11 so as to avoid the lower area (the lower right area of the front window 2) of the optical sheet 20 on which the handle 4 and the instruments 5 are arranged. Therefore, the degree of freedom of the arrangement position of the image source 11 with respect to the driver's seat of the automobile 1 can be improved.
Therefore, in the display device 10 of the first embodiment, the design and manufacture of the optical sheet 20 are easy, and good optical performance can be obtained. Further, in the display device 10 according to the first embodiment, the degree of freedom in the area where the video source 11 is arranged can be improved.

  Further, in the display device 10 of the first embodiment, when the arrangement direction R1 of the unit optical shapes 21a is viewed from the thickness direction (Y direction) of the optical sheet 20, the emission position 11a of the image light L of the image source 11 is different from the emission position 11a. The optical sheet 20 is inclined to the same side (right side) as the line connecting the geometric center C1 of the optical sheet 20. Thereby, the display device 10 of the first embodiment can reflect the image light projected from the lower left side to the optical sheet 20 more efficiently on the driver side.

  In addition, human eyes tend to recognize lines extending in the left-right direction more easily than lines inclined in the left-right direction or lines extending in the up-down direction. Therefore, as described above, by arranging the array direction R1 of the unit optical shapes 21a on the same side (right side) as the line connecting the emission position 11a and the geometric center C1 of the optical sheet 20, the unit optical shapes 21a are inclined. The line (broken line in FIG. 2A) attributable to 21a can be inclined with respect to the left-right direction (X direction), making it difficult for the driver's eyes to visually recognize the line.

  Further, since the optical sheet 20 of the first embodiment reflects the image light L to the driver side at the reflection layer 22, the reflectance is higher than that of a conventional laminated glass having a wedge-shaped cross section of the intermediate layer, Brighter images can be displayed to the driver. Further, since it is not necessary to use a high-output light source as the image source 11, it is possible to reduce power consumption and extend the life.

(2nd Embodiment)
Next, a display device 10 according to a second embodiment will be described.
In the following description and drawings, members, devices, and the like that perform the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and overlapping descriptions are appropriately omitted (other embodiments). The same applies to).
FIG. 4 is a diagram illustrating a display device 10 according to the second embodiment. FIG. 4A is a front view of the optical sheet 20 viewed from the driver side in the thickness direction. FIG. 4B is a cross-sectional view in a section parallel to the thickness direction (Y direction) and parallel to the arrangement direction of the unit optical shapes 21a, that is, a view showing a section b in FIG. 4A.

The display device 10 of the second embodiment is different from the first embodiment in that the unit optical shape 21a provided on the optical shape layer 21 of the optical sheet 20 is formed in a circular Fresnel lens shape as shown in FIG. Of the display device 10.
The optical sheet 20 is disposed on the right side (in front of the driver's seat) of the inner surface (inside the vehicle) of the front window 2 (see FIG. 1), similarly to the optical sheet 20 of the first embodiment (see FIG. 1). An optical shape layer 21, a reflective layer 22, and a back layer 23 are sequentially stacked.

The optical shape layer 21 is a layer having light transmissivity, and as shown in FIG. 4A, a circular Fresnel lens shape in which a plurality of unit optical shapes 21a are arranged concentrically around a point C2. Side (-Y side). In this circular Fresnel lens shape, the optical center (Fresnel center) C2 is located outside the outer shape of the optical sheet 20 (in the present embodiment, the lower left side of the optical sheet 20) when viewed from the thickness direction (Y direction). ing.
In the unit optical shape 21a of the second embodiment, when viewed from the thickness direction of the optical sheet 20, a line segment connecting the optical center C2 and the geometric center C1 of the optical sheet 20 corresponds to the image of the image source 11. The light L is inclined to the same side as the line connecting the emission position 11a of the light L and the geometric center C1 of the optical sheet 20. With such a configuration, the optical sheet 20 can efficiently reflect image light projected from the lower left side to the driver side.

As shown in FIG. 4B, the unit optical shape 21a is parallel to a direction (thickness direction, Y direction) orthogonal to the sheet surface (XZ plane), and is parallel to the arrangement direction of the unit optical shapes 21a. Is a substantially triangular shape.
The unit optical shape 21a is convex on the back side, and includes an incident surface 21b on which image light is directly incident, and an opposing surface 21c facing the incident surface 21b.
In the second embodiment, in the use state shown in FIG. 2A, the unit optical shape 21a is such that the entrance surface 21b is located above the opposing surface 21c (+ Z side) with the top t interposed therebetween.

  Here, the angle formed by the plane of incidence 21b of the unit optical shape 21a and a plane parallel to the sheet plane (XZ plane) is α2. The angle formed by the facing surface 21c and the surface parallel to the sheet surface is β2 (β2> α2). Further, the arrangement pitch of the unit optical shapes 21a is P2, and the height of the unit optical shapes 21a (the dimension from the top t in the thickness direction to the point v at the valley between the unit optical shapes 21a) is h2. Preferably, the arrangement pitch P2 is 100 to 600 μm, the angle α2 is 1 to 40 °, the angle β2 is 80 to 100 °, and the height 2 is 1 to 500 μm. More preferably, the arrangement pitch P2 is 200 to 500 μm, the angle α2 is 5 to 30 °, the angle β2 is 90 °, and the height h2 is 100 to 300 μm.

In FIG. 4, for ease of understanding, the arrangement pitch P2 and angles α2 and β2 of the unit optical shapes 21a are shown to be constant in the arrangement direction of the unit optical shapes 21a. However, the unit optical shape 21a of the present embodiment actually has a constant arrangement pitch P2 and the like, but gradually increases as the angle α2 moves away from the point C2 which becomes the Fresnel center in the arrangement direction of the unit optical shapes 21a. I have. In addition, the height h2 also changes accordingly.
The arrangement pitch P2 is not limited to this, and the arrangement pitch P2 may be configured to gradually change along the arrangement direction of the unit optical shapes 21a, and the size of the image projected from the image source 11 and the projection angle ( The angle of incidence of the image light on the surface of the optical sheet 20 on the driver side), the size of the image reflected on the driver side, the refractive index of each layer, and the like can be appropriately changed.

  In the display device 10 according to the second embodiment described above, similarly to the first embodiment, the design and manufacture of the optical sheet 20 are easy, and good optical performance can be obtained. Also, in the display device 10 of the second embodiment, similarly to the first embodiment, the image source 11 is moved to the lower area of the optical sheet 20 (the right side of the front window 2) on which the handle 4 and the instruments 5 are arranged. (The lower region) can be avoided, so that the degree of freedom of the arrangement position of the image source 11 with respect to the driver's seat of the automobile 1 can be improved.

  In the display device 10 of the second embodiment, the unit optical shape 21a is formed in a circular Fresnel shape, and the optical center C2 of the circular Fresnel lens shape is defined by the optical sheet 20 when viewed from the thickness direction of the optical sheet 20. The line connecting the optical center C2 and the geometric center C1 of the optical sheet 20 is located outside the outer shape when viewed from the thickness direction of the optical sheet 20, and the line of the image light L of the image source 11 is formed. Is inclined to the same right side as the line segment connecting the emission position 11a of the optical sheet 20 and the geometric center C1 of the optical sheet 20. Thereby, the display device 10 of the present embodiment can more efficiently reflect the image light projected from the lower left side to the optical sheet 20 to the driver side.

(Third embodiment)
Next, a display device 10 according to a third embodiment will be described.
FIG. 5 is a diagram illustrating a display device 10 according to the third embodiment. FIG. 5A is a cross-sectional view on the center line of the front window 2 in the left-right direction, and is a partial cross-sectional view corresponding to a cross-section b in FIG. FIG. 5B is a cross-sectional view illustrating another configuration of the front window 2 in the third embodiment.
The display device 10 of the third embodiment includes an image source 11, a projection optical system 12, and a front window 2 including an optical sheet 20. Among them, the configurations of the image source 11 and the projection optical system 12 are the same as those of the display device 10 of the first embodiment, and therefore, only the differences will be described here.

In the display device 10 according to the third embodiment, the optical sheet 20 is disposed inside the front window 2. That is, the optical sheet 20 of the present embodiment is used in the form of a so-called laminated glass sandwiched between two glasses (31, 34) described later and integrally formed with the front window 2. The optical sheet 20 is arranged on the entire surface of the front window 2.
As shown in FIG. 5A, the front window 2 of the present embodiment includes a first glass (first support) 31, a first intermediate layer 32, an optical sheet 20, a second intermediate layer 33, and a second glass ( (Second support) 34.

  The first glass 31 is a transparent member disposed on the most indoor side of the front window 2. As the first glass 31, for example, a material such as soda lime glass (blue plate glass), borosilicate glass (white plate glass), quartz glass, soda glass, and potash glass can be used. Further, it is preferable that the thickness of the first glass 31 be in a range of 2 to 3 mm.

  The first intermediate layer 32 is a layer disposed between the first glass 31 and the optical sheet 20. The first glass 31 and the optical sheet 20 are joined by a first intermediate layer 32. The first intermediate layer 32 is arranged to prevent fragments of the first glass 31 from scattering when the front window 2 is damaged. As the first intermediate layer 32, for example, PVB (polyvinyl brilar) can be used. The thickness of the first intermediate layer 32 is preferably in the range of 0.3 to 0.8 mm. Further, it is desirable that the refractive index of the first intermediate layer 32 is equal to that of the first glass 31 and the optical shape layer 21 (optical sheet 20).

The optical sheet 20 is a sheet that, like the optical sheet 20 of the first embodiment, reflects a part of the incident light to the driver side and transmits other light. The basic configuration of the optical sheet 20 is the same as in the first embodiment. The optical sheet 20 of the present embodiment is different from the first embodiment in that a base layer 24 is provided on the driver side (+ Y side) of the optical shape layer 21.
The base material layer 24 is a flat plate-shaped member that serves as a base when the optical shape layer 21 is formed. The base layer 24 is formed of, for example, a polyester resin such as PET having high light transmittance, an acrylic resin, a styrene resin, an acrylic styrene resin, a polycarbonate resin, an alicyclic polyolefin resin, or the like.

The second intermediate layer 33 is a layer disposed between the second glass 34 and the optical sheet 20. The second glass 34 and the optical sheet 20 are joined by the second intermediate layer 33. The second intermediate layer 33 is arranged to prevent fragments of the second glass 34 from scattering when the front window 2 is damaged. As the second intermediate layer 33, PVB can be used similarly to the first intermediate layer 32. The thickness of the second intermediate layer 33 is preferably in the range of 0.3 to 0.8 mm. Further, it is desirable that the refractive index of the second intermediate layer 33 is equal to that of the first glass 31 and the optical shape layer 21.
The second glass 34 is a transparent member disposed on the rearmost side (+ Z side) of the optical sheet 20. As the second glass 34, the same material as the first glass 31 can be used. The thickness of the second glass 34 is preferably in the range of 2 to 3 mm.

  In the front window 2 of the present embodiment, the first intermediate layer 32 and the second intermediate layer 33 extend from the upper end (the uppermost end in the + Z direction) to the lower end (the lowermost end in the −Z direction) of the front window 2. In the range, the layers are formed such that the layer thicknesses are uniform. That is, in the front window 2, the cross section of the first intermediate layer 32 and the second intermediate layer 33 is not a wedge shape but a rectangular shape having a uniform layer thickness in a range from the upper end to the lower end. Therefore, the design and manufacture of the front window 2 including the optical sheet 20 become easier as compared with a conventional laminated glass having a wedge-shaped cross section of the intermediate layer.

Next, the movement of the image light L incident on the front window 2 and the light G from the outside will be described.
As shown in FIG. 5A, the image light L projected from the image source 11 enters the driver's side surface of the front window 2 via the projection optical system 12. Part of the image light L incident on the front window 2 is transmitted through the first glass 31, the first intermediate layer 32, and the base material layer 24, is incident on the incident surface 21b of the unit optical shape 21a, and is reflected. At the layer 22, the light is reflected toward the driver. Then, part of the light G from the outside is transmitted from the rear side of the front window 2 to the driver side. Therefore, the driver can see the light G from outside and the image light L in an overlapping manner. Further, other light L2 other than the image light L transmits through the reflective layer 22, then transmits through the back layer 23, the second intermediate layer 33, and the second glass 34, and the rear side of the front window 2 (+ Z Side). Further, another part of the light L3 of the image light L is reflected obliquely upward (+ Y side) by the first glass 31 of the front window 2. Therefore, most of the light L3 does not reach the driver.

Further, the optical sheet 20 in the third embodiment may have a configuration as shown in FIG. In the optical sheet 20 shown in FIG. 5B, a base layer 24 is provided between the optical shape layer 21 and the first intermediate layer 32 and between the back layer 23 and the second intermediate layer 33, respectively. This is different from the optical sheet 20 shown in FIG. Other configurations are the same as those of the optical sheet 20 shown in FIG. Also in the front window 2 including the optical sheet 20 of the present embodiment, the same optical characteristics as those of the front window 2 shown in FIG.
Further, in the present embodiment, since the base material layer 24 is disposed on the driver side, the flatness of the optical sheet 20 on the driver's seat side can be improved. Therefore, the optical performance of the optical sheet 20 can be further improved.

The front window 2 according to the third embodiment described above has a uniform layer thickness in the range from the upper end to the lower end, and is designed as compared with a conventional laminated glass having a wedge-shaped cross section of the intermediate layer. And it is easy to manufacture and can be manufactured at low cost.
Therefore, in the display device 10 including the front window 2 according to the third embodiment, similarly to the first embodiment, the design and manufacture of the optical sheet 20 are easy, and good optical performance can be obtained. Further, in the display device 10 of the third embodiment, similarly to the first embodiment, the image source 11 is arranged so as to avoid the area under the optical sheet 20 where a large number of the handles 4 and the instruments 5 are arranged. Therefore, the degree of freedom of the arrangement position of the image source 11 with respect to the driver's seat of the automobile 1 can be improved.
Further, since the optical sheet 20 of the present embodiment is formed integrally with the front window 2, the optical sheet 20 can be made inconspicuous from the front window 2. Therefore, the appearance of the automobile 1 on which the front window 2 of the present embodiment is mounted can be further improved.

(Fourth embodiment)
Next, as a fourth embodiment, a front window 2 in which a reflection layer 22 is formed on a part of the optical shape layer 21 will be described.
FIG. 6 is a diagram illustrating a front window 2 according to the fourth embodiment. FIG. 6A is a sectional view of the front window 2 in the fourth embodiment, and is a partial sectional view corresponding to FIG. 5A. FIG. 6B is a diagram illustrating a method of forming the reflection layer 22 on a part of the optical shape layer 21.

  In the third embodiment described above, the optical sheet 20 is formed integrally with the front window 2. In the configuration of the third embodiment, the reflection layer 22 is formed over the entire area of the optical shape layer 21. On the other hand, in the configuration of the third embodiment, the reflection layer 22 may be formed in a part of the optical shape layer 21. For example, as in the first embodiment, there is a case where an image is projected only in front of the driver's seat on the front window 2.

  As shown in FIG. 6A, in the optical sheet 20 of the fourth embodiment, the reflection layer 22 is formed in a part of the optical shape layer 21. In the optical shape layer 21, a resin forming the back layer 23 is filled in a region where the reflection layer 22 is not formed. That is, in the optical shape layer 21, the surface of the region where the reflective layer 22 is not formed is directly bonded to the back layer 23. Thereby, the thickness of the optical sheet 20 becomes uniform in the vertical direction (Z direction).

  In order to form the reflective layer 22 in a partial area of the optical shape layer 21, for example, as shown in FIG. 6B, a vapor deposition metal (aluminum) is formed on the entrance surface 21b of the unit optical shape 21a by a vacuum vapor deposition method. 2.) When depositing AL, the stencil mask 100 is arranged on the side of the optical shape layer 21 on which the unit optical shape 21a is formed. The stencil mask 100 is a plate-shaped member in which an opening 101 is formed only in a portion of the optical shape layer 21 where the reflection layer 22 is formed. By disposing the stencil mask 100 and masking and vapor-depositing the deposition metal AL on the incident surface 21b of the unit optical shape 21a, the reflection layer 22 can be formed in a partial region of the optical shape layer 21.

(Fifth embodiment)
Next, as a fifth embodiment, a configuration in which the optical sheet 20 is disposed in a part of the front window 2 will be described.
FIG. 7 is a diagram illustrating the front window 2 of the fifth embodiment, and is a partial cross-sectional view corresponding to FIG.
As shown in FIG. 7, in the front window 2 of the fifth embodiment, the optical sheet 20 is disposed only in a portion where the projection of an image by the reflective layer 22 is required. The configuration of the optical sheet 20 is the same as that of the third embodiment. In the front window 2, an intermediate layer 35 is disposed in a region where the optical sheet 20 is not disposed. The intermediate layer 35 is a sheet material in which only the portion where the optical sheet 20 is arranged is cut out in a rectangular shape. As the intermediate layer 35, PVB can be used as in the case of the first intermediate layer 32 and the second intermediate layer 33. By setting the thickness of the intermediate layer 35 to be the same as that of the optical sheet 20, the thickness of the layer on which the optical sheet 20 and the intermediate layer 35 are arranged can be made uniform in the vertical direction (Z direction).
The configuration of the present embodiment is applied, for example, when projecting an image only in front of the driver's seat on the front window 2 as in the first embodiment.

(Sixth embodiment)
Next, an embodiment in which a dielectric multilayer film is formed as the reflection layer 22 formed on the unit optical shape 21a (incident surface 21b) will be described. FIG. 8 is a diagram illustrating an optical sheet 20 according to the sixth embodiment, and is a partial cross-sectional view of a unit optical shape 21a on which a reflective layer 22 made of a dielectric multilayer film is formed.
The dielectric multilayer film is formed by alternately stacking a dielectric film having a high refractive index (hereinafter, also referred to as “dielectric film DH”) and a dielectric film having a low refractive index (hereinafter, also referred to as “dielectric film DL”). Film. In the present embodiment, the reflective layer 22 is formed by forming five dielectric films DH and DL (hereinafter, also referred to as “layers”) on the incident surface 21b of the unit optical shape 21a.

The ratio of the reflectance and the transmittance of the dielectric multilayer film can be controlled by the number of layers. When the number of layers of the dielectric multilayer film is increased, incident light is attenuated and becomes reflected light, so that it is hardly transmitted. Therefore, in order to make the transmittance 70% or more, it is desirable to set the number of layers of the dielectric multilayer film in the range of 3 to 7 layers.
For the dielectric multilayer film, for example, TiO ₂ , Ta ₂ O ₃ or the like can be used as the dielectric film DH. Further, as the dielectric film DL, for example, SiO ₂ , MgF ₂ or the like can be used. These dielectric films can be formed by, for example, a technique such as vacuum deposition or sputtering.

  Since the dielectric film DH and the dielectric film DL do not absorb light, a higher reflectance can be obtained as compared with a metal such as aluminum. According to the experiments of the present inventors, in the optical sheet 20 manufactured under the same conditions, when the transmittance was set to 70%, the reflectance of the deposited aluminum film was 1.5%, whereas the reflectance was 1.5%. The reflectance of the body multilayer film was 30%.

(Seventh, eighth, and ninth embodiments)
Next, each embodiment of a front window having a function of heat insulation, sound insulation and the like will be described.
FIG. 9 is a view for explaining each of the front windows 2 of the seventh, eighth and ninth embodiments, and is a partial sectional view corresponding to FIG.
FIG. 9A is a cross-sectional view of the front window 2 in the seventh embodiment.
As shown in FIG. 9A, in the front window 2 of the seventh embodiment, a heat ray reflective layer 36 is disposed between the base material layer 24 and the first intermediate layer 32. The heat ray reflective layer 36 is a layer that reflects a heat ray incident from the outside, and is disposed closer to the driver (+ Y side) than the optical sheet 20. Further, the heat ray reflective layer 36 is disposed on the entire surface of the front window 2, similarly to the optical sheet 20.

As the heat ray reflective layer 36, for example, cholesteric liquid crystal can be used. Cholesteric liquid crystals can selectively reflect only a desired wavelength in the wavelength range from visible light to infrared light. Therefore, by adjusting the composition of the cholesteric liquid crystal, visible light can be transmitted and only infrared rays (heat rays) can be reflected. As a raw material of the cholesteric liquid crystal, for example, C0319 (manufactured by Tokyo Chemical Industry Co., Ltd.) can be used.
Since the front window 2 of the present embodiment includes the heat ray reflective layer 36, it is possible to efficiently block heat rays incident from the outside. Therefore, according to the front window 2 of the present embodiment, it is possible to improve indoor cooling efficiency and to achieve power saving.

FIG. 9B is a cross-sectional view of the front window 2 in the eighth embodiment.
In the front window 2 of the eighth embodiment, the back layer 23 of the optical sheet 20 is formed of a resin having high sound insulation.
As the resin having a high sound insulation property, a resin having a lower hardness than PVB or EVA (ethylene-vinyl acetate copolymer), such as a polyolefin-based material, an elastomer, or a gel, is desirable. For example, Hibler 5127 (manufactured by Kuraray Co., Ltd.) or the like can be used. In addition, PVB generally used as a sound insulation layer can be used. It is desirable that the refractive index of the material used as the back layer 23 be equal to that of the optical shape layer 21.
In the front window 2 of the present embodiment, since the back layer 23 is formed of a resin having high sound insulation, the sound insulation in the room can be improved without increasing the thickness of the optical sheet 20.

FIG. 9C is a cross-sectional view of the front window 2 in the ninth embodiment.
As shown in FIG. 9C, in the front window 2 of the ninth embodiment, a heat ray reflective layer 36 is disposed between the base material layer 24 and the first intermediate layer 32. The heat ray reflective layer 36 is the same as in the seventh embodiment. In the front window 2, the back layer 23 of the optical sheet 20 is formed of a resin having high sound insulation. The resin having high sound insulation properties is the same as in the eighth embodiment.
According to the front window 2 of the present embodiment, it is possible to efficiently block heat rays entering from the outside world, and to improve indoor sound insulation.

(Tenth embodiment)
Next, as a tenth embodiment, an area where the optical sheet 20 is arranged in the front window 2 will be described.
FIG. 10 is a diagram illustrating a region where the optical sheet 20 according to the first embodiment is arranged, and is a diagram illustrating a state in which the front window 2 side (the traveling direction of the vehicle) is viewed from the driver's seat of the vehicle 1.
As shown in FIG. 10A, the optical sheet 20 may be attached to a lower portion of the inner surface of the front window 2 (the entire surface in the left-right direction).
Further, as shown in FIG. 10B, the optical sheet 20 may be attached to the entire inside surface of the front window 2.
The arrangement of the optical sheet 20 shown in FIGS. 10A and 10B can be applied to the optical sheet 20 of the second embodiment.

FIG. 11 is a diagram illustrating a region where the optical sheet 20 according to the third embodiment is arranged, and is a diagram illustrating a state where the front window 2 side is viewed from the driver's seat of the automobile 1. The optical sheet 20 of the third embodiment is used in the form of a laminated glass formed integrally with the front window 2.
As shown in FIG. 11A, the optical sheet 20 may be arranged in a region on the right side (in front of the driver's seat) of the front window 2.
Further, as shown in FIG. 11B, the optical sheet 20 may be disposed below the front window 2 (the entire surface in the left-right direction).

In the embodiment shown in FIGS. 11A and 11B, for example, the configuration of the optical sheet 20 shown in FIG. 7 can be applied. In the front window 2 shown in FIGS. 11A and 11B, in a region where the optical sheet 20 is not disposed, the intermediate layer 35 having a high transmittance is disposed (see FIG. 7). Good visibility can be obtained.
In addition, as shown in FIG. 11C, the optical sheet 20 of the fourth embodiment (see FIG. 6) may be arranged on the entire surface of the front window 2. In the optical sheet 20 of the present embodiment, the reflection layer 22 is formed only on the lower portion (the entire surface in the left-right direction) of the front window 2. Further, in the optical sheet 20 of the present embodiment, the reflection layer 22 is not formed on the upper portion (the entire surface in the left-right direction) of the front window 2. Therefore, the optical sheet 20 of the present embodiment can obtain a sufficient transmittance above the front window 2 without obstructing the driver's view.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made as in the modifications described below. Within the technical scope of In addition, the effects described in the embodiments merely enumerate the most preferable effects resulting from the present invention, and are not limited to the effects described in the embodiments. Note that the configurations of the above-described embodiment and modified embodiments described later can be combined as appropriate, but detailed description is omitted.

(Modified form)
(1) In the above-described embodiment, fine concavo-convex shapes may be formed on the opposing surface 21c of the unit optical shape 21a. Even if the optical shape layer 21 and the back layer 23 are formed of materials having the same refractive index, a small difference in refractive index may occur between them. In that case, a part of the light transmitted through the opposing surface 21c may be reflected on the opposing surface 21c and visually recognized by the driver as a double image (ghost). However, by forming fine irregularities on the opposing surface 21c, light incident on the opposing surface 21c can be diffused to suppress the occurrence of a double image.

(2) In the above-described embodiment, the example in which the display device 10 is disposed in the driver's seat of the automobile 1 is described. However, the display device 10 is not limited thereto, and may be disposed in the driver's seat of another vehicle. Good. Further, the display device 10 may be arranged not only in the front window 2 but also in a side window, a rear window, or the like. Further, the display device 10 can also be applied to a shop window or the like in a store or the like that transmits external light such as a background. In this case, for example, by attaching the optical sheet 20 (first embodiment) to the inner surface of the shop window and disposing the image source 11 diagonally below or above the left or right side of the optical sheet 20, the store The goods displayed in the show window can be shown from the outside, and information on the goods and the like can be displayed from the video source 11.

(3) In the above-described embodiment, the surface of the optical sheet 20 on the driver side (+ Y side) may be subjected to hard coat processing for the purpose of preventing damage. In this hard coat treatment, for example, an ultraviolet curable resin (for example, urethane acrylate or the like) having a hard coat function may be applied to the surface of the optical sheet 20 on the driver side to form a hard coat layer.

DESCRIPTION OF SYMBOLS 1 Automobile 2 Front window 10 Display device 11 Image source 20 Optical sheet 21 Optical shape layer 21a Unit optical shape 21b Incident surface 21c Opposing surface 22 Reflective layer 23 Back layer 31 First glass 32 First intermediate layer 33 Second intermediate layer 34 First 2 glass 36 heat ray reflective layer

Claims (6)

An image source for projecting image light,
An optical sheet that reflects part of the image light projected from the image source to the observer side,
With
The optical sheet,
A first optical shape layer in which a plurality of unit optical shapes each having a first inclined surface and a second inclined surface are arranged,
A second optical shape layer laminated on a surface of the first optical shape layer on which the unit optical shape is provided;
A reflection layer formed on at least a part of the first inclined surface, reflecting a part of incident light, and transmitting the other;
With
The image source is
When the optical sheet is viewed from the thickness direction, a line segment passing through the exit position of the image light and the geometric center of the optical sheet passes through the geometric center of the optical sheet and is parallel to the vertical direction. It is arranged to be inclined with respect to the line,
The arrangement direction of the first optical shape layer in the optical sheet is the same as a line segment passing through the emission position of the image light and the geometric center of the optical sheet when the optical sheet is viewed from the thickness direction. Inclined to the side,
The first optical shape layer has a fine uneven shape on the second inclined surface of the unit optical shape,
A display device characterized by the above-mentioned. The display device according to claim 1,
The first optical shape layer has a linear Fresnel lens shape in which a plurality of the unit optical shapes are arranged in parallel,
Display device. The display device according to claim 1,
The first optical shape layer has a circular Fresnel lens shape in which a plurality of the unit optical shapes are arranged concentrically.
Display device. The display device according to any one of claims 1 to 3, wherein
A first support disposed on the viewer side of the optical sheet;
A first intermediate layer disposed between the first support and the optical sheet;
A second support disposed on a side of the optical sheet opposite to a viewer;
A second intermediate layer disposed between the optical sheet and the second support;
With
The first intermediate layer and the second intermediate layer have a uniform layer thickness in a range from an upper end to a lower end of the optical sheet.
A display device characterized by the above-mentioned. The display device according to any one of claims 1 to 4, wherein
The reflective layer is a metal layer formed in a specific region of the optical sheet,
A display device characterized by the above-mentioned. The display device according to any one of claims 1 to 4, wherein
The reflection layer is a dielectric multilayer film,
A display device characterized by the above-mentioned.

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