Vehicle display device

Abstract

The present invention provides an in-vehicle display device that can suppress the transmission of reflected ambient light to the user's eyebox, and also suppress the obstruction of the display light. [Solution] The in-vehicle display device 1 is an in-vehicle display device 1 that forms a virtual image by projecting display light onto a display medium of a vehicle 2, and comprises a display device 10 that displays a virtual image by emitting display light, and an optical body 20 disposed on the display device 10, the optical body 20 having a base and an anti-reflective layer 21, the base including a plurality of prisms 22 whose cross-section is triangular when cut by a plane perpendicular to the vehicle width direction of the vehicle 2, each of the plurality of prisms 22 having a first surface 22a facing the front side of the vehicle 2 and a second surface 22b facing the rear side of the vehicle 2, and the anti-reflective layer 21 is disposed on the first surface 22a.

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle display device.

Background Art

[0002] As a conventional technique, a windshield display device is disclosed that is mounted on an automobile, projects light from a light source onto the windshield, and projects reflected light to the user's eye box, thereby making an image visible in a superimposed manner with the scene in front of the windshield.

[0003] For example, Patent Document 1 discloses a windshield display device that can achieve both suppression of reflection of a light source on the windshield and miniaturization. The windshield display device includes a housing portion provided in an instrument panel of a vehicle and having an opening, and an image generation unit in which a plurality of main pixels each composed of a plurality of sub-pixels are repeatedly arranged in one direction and another direction intersecting the one direction, and a viewpoint division element disposed over the image generation unit.

[0004] Further, Patent Document 2 discloses a head-up display device for preventing extraneous light from being reflected by a transparent panel and reaching the driver's eyes. The head-up display device is provided with a shutter in which a plurality of rotatable louvers are arranged with their respective axes parallel to each other.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of Invention

Problem to be Solved by the Invention

[0006] However, in Patent Document 1, external light may be reflected off the surface of the windshield display device and enter the user's eye box. Therefore, it is conceivable to tilt the orientation of the windshield display device to suppress the entry of external light into the eye box. However, this would create unnecessary space on the dashboard where the windshield display device is placed, or affect the design aesthetics.

[0007] In the head-up display device described in Patent Document 2, external light can be suppressed by arranging multiple louvers. Therefore, in the head-up display device of Patent Document 2, it is not necessary to tilt the orientation of the head-up display device, which can prevent the creation of unnecessary space and affect the design. However, because the head-up display device of Patent Document 2 has a structure in which multiple louvers are arranged, there is a problem that the thickness of the multiple louvers obstructs the display light.

[0008] Therefore, the purpose of this disclosure is to provide an in-vehicle display device that can suppress the external light reflected by the in-vehicle display device from reaching the user's eye box, and also suppress the obstruction of the display light. [Means for solving the problem]

[0009] An in-vehicle display device according to one aspect of the present disclosure is an in-vehicle display device that forms a virtual image by projecting display light onto a display medium of a vehicle, comprising a display device that displays the virtual image by emitting the display light, and an optical body disposed on the display device, wherein the optical body has a substrate and an anti-reflective layer, the substrate includes a plurality of prisms whose cross-section is triangular when cut by a plane perpendicular to the vehicle width direction, each of the plurality of prisms has a first surface facing the front side of the vehicle and a second surface facing the rear side of the vehicle, and the anti-reflective layer is disposed on the first surface. [Effects of the Invention]

[0010] The in-vehicle display device of this disclosure can suppress the external light reflected by the in-vehicle display device from reaching the user's eye box, and can also suppress the obstruction of the display light. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view showing a vehicle equipped with an in-vehicle display device according to an embodiment. [Figure 2] Figure 2 is a schematic diagram showing the in-vehicle display device and vehicle according to the embodiment as viewed from the right. [Figure 3A] Figure 3A is a partially enlarged cross-sectional view showing the display element and the optical body. [Figure 3B] Figure 3B is another enlarged cross-sectional view showing the display element and the optical body. [Figure 3C] Figure 3C is another enlarged cross-sectional view showing the display element and the optical body. [Figure 4A] Figure 4A is a partially enlarged cross-sectional view showing a display element such as a liquid crystal display and an optical body. [Figure 4B] Figure 4B is another enlarged cross-sectional view showing a display element such as a liquid crystal display and an optical body. [Figure 5A] Figure 5A is a schematic diagram showing an in-vehicle display device and vehicle having a display device using a light guide plate, viewed from the right. [Figure 5B] Figure 5B is a partially enlarged cross-sectional view showing a display device and optical body using a light guide plate. [Figure 5C] Figure 5C is a partially enlarged cross-sectional view showing a display device and optical body using an optical medium and a light guide plate. [Figure 6A] Figure 6A is a schematic diagram showing an in-vehicle display device and vehicle equipped with a projector, viewed from right to left. [Figure 6B] Figure 6B is a partially enlarged cross-sectional view showing a display device and optical body using a projector. [Figure 6C] Figure 6C is another enlarged cross-sectional view showing a display device and optical body using a projector. [Mode for Carrying Out the Invention]

[0012] Hereinafter, embodiments will be specifically described with reference to the drawings.

[0013] Note that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, constituent elements, arrangement positions of constituent elements, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements not described in the independent claims will be explained as optional constituent elements.

[0014] Each drawing is a schematic view, and is not necessarily strictly illustrated. Therefore, for example, the scales and the like in the respective drawings do not necessarily match. In each drawing, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions will be omitted or simplified.

[0015] Further, in the following embodiments, expressions such as full length direction, triangular shape, and substantially parallel are used. For example, the full length direction not only means a perfect full length direction, the triangular shape not only means a perfect triangle, and substantially parallel not only means perfectly parallel, but also means substantially full length direction, substantially triangular, and substantially parallel, that is, including an error of, for example, about several percent. In addition, the full length direction, triangular shape, and substantially parallel mean being in the full length direction, triangular shape, and substantially parallel within a range where the effects of the present disclosure can be achieved. The same applies to other expressions using "direction", "shape", and "substantially".

[0016] In Figure 1, the direction in which a user is seated in the vehicle and looking straight ahead, along the overall length of the vehicle, is defined as the forward direction, and the direction opposite to the forward direction is defined as the rear direction. Furthermore, in the direction perpendicular to the forward and rear directions and along the overall length of the vehicle, when a user is looking forward from inside the vehicle, the direction to the user's right hand is defined as the right direction, and the direction to the user's left hand is defined as the left direction. The direction toward the windshield relative to the in-vehicle display device is defined as the upward direction, and the direction opposite to the upward direction is defined as the downward direction. The directions in Figure 1 may also be applied in Figures 2 and later.

[0017] (Embodiment) <Structure> The in-vehicle display device 1 of this disclosure will be described in detail below with reference to Figures 1 to 3C.

[0018] Figure 1 is a perspective view showing a vehicle 2 equipped with an in-vehicle display device 1 according to an embodiment. Figure 2 is a schematic diagram showing the in-vehicle display device 1 and vehicle 2 according to an embodiment viewed along the rightward direction. Figure 3A is a partially enlarged cross-sectional view showing the display element 11 and the optical body 20. Figure 3B is another partially enlarged cross-sectional view showing the display element 11 and the optical body 20. Figure 3C is yet another partially enlarged cross-sectional view showing the display element 11 and the optical body 20.

[0019] First, the general configuration of the in-vehicle display device 1 will be described. In this embodiment, it is assumed that the in-vehicle display device 1 is mounted on the vehicle 2, and that the surface 11a of the in-vehicle display device 1 is in a position approximately parallel to the horizontal plane. Note that the position of the in-vehicle display device 1 shown in this embodiment is merely an example and is not limited to this embodiment.

[0020] As shown in Figures 1 and 2, the in-vehicle display device 1 is, for example, a head-up display positioned on the dashboard 5 (also called the instrument panel) of a vehicle 2 traveling on a road surface. Above the dashboard 5 of the vehicle 2 is a windshield 3 (also called the front shield).

[0021] The in-vehicle display device 1 is mounted on the vehicle 2 and projects an image onto a display medium that can transmit and reflect display light, thereby forming a virtual image on the side of the display medium away from the user.

[0022] For example, the in-vehicle display device 1 can display a virtual image represented by the display light to a user, such as a driver, by reflecting the display light representing the projected image emitted from the display device 10 onto a display medium such as a windshield 3 or a translucent combiner. In other words, the in-vehicle display device 1 can display the projected image indicated by the display light on the display medium by projecting the display light emitted from the display device 10 onto the display medium. As a result, the projected image projected onto the display medium of the vehicle 2 is visible to the user. Figures 1 and onward of this embodiment illustrate the case in which the in-vehicle display device 1 projects the display light onto the windshield 3.

[0023] Here, the display light is light that represents a projected image including numbers, letters, and figures, and is displayed as a virtual image in front of the windshield 3. The projected image can be a still image or a moving image, and is an image of numbers, letters, and figures.

[0024] As shown in Figure 3A, the in-vehicle display device 1 comprises a display device 10 and an optical body 20.

[0025] The display device 10 can display a virtual image on the windshield 3 by emitting display light.

[0026] Specifically, the display device 10 has a display element 11 positioned opposite the windshield 3. The display element 11 has the function of displaying a projected image, and emits light when illuminated from the back side by light from a light-emitting module such as an LED (Light Emitting Diode), emitting display light that becomes the projected image projected onto the windshield 3. Based on control instructions from the ECU (Electronic Control Unit) mounted on the vehicle 2, the display element 11 emits display light that shows a projected image including numbers, characters, figures, etc. Such a display element 11 is driven by DC power supplied from the power supply unit of the vehicle 2.

[0027] An optical body 20 is arranged on the surface 11a of the display element 11 in the display device 10. The optical body 20 is in the form of a sheet, extends along the overall length direction and the width direction of the vehicle 2, and covers the display element 11.

[0028] The optical body 20 may be attached to the surface 11a of the display element 11 with a light-transmitting adhesive or the like. In this case, the surface 11a of the display element 11 is the light-emitting surface from which the display device 10 emits display light. In this embodiment, the surface 11a of the display element 11 faces upwards towards the vehicle 2.

[0029] Furthermore, the optical element 20 may be integrally configured with the display element 11.

[0030] The optical element 20 can adjust the emission angle of the display light emitted by the display device 10. The optical element 20 is made of, for example, a light-transmitting resin material, glass, or the like.

[0031] The optical body 20 comprises a substrate and an anti-reflective layer 21.

[0032] The base includes a plurality of prisms 22, each having a triangular cross-section when cut by a plane perpendicular to the vehicle width direction of the vehicle 2. Each of the plurality of prisms 22 is a microprism with a fine structure, having an elongated shape extending along the vehicle width direction. Each of the plurality of prisms 22 plays a role in refracting the display light in a specific direction and adjusting the direction of the emitted display light. As a result, the display light emitted from the display device 10 is directed in a predetermined direction.

[0033] Each of the multiple prisms 22 in the substrate has a first surface 22a and a second surface 22b.

[0034] The first surface 22a faces the front side of the vehicle 2 and extends along the width direction of the vehicle. The first surface 22a does not necessarily have to be perfectly parallel to the width direction of the vehicle. The first surface 22a is inclined upward from the front to the rear of the vehicle 2 relative to the surface 11a of the display element 11. An anti-reflective layer 21 is provided on the first surface 22a. The inclination direction of the first surface 22a may be parallel to the direction in which the display light is emitted from the second surface 22b.

[0035] The anti-reflective layer 21 has the function of suppressing the reflection of ambient light incident on the vehicle 2. For example, an AR (Anti-Reflection) coating film can be used as the anti-reflective layer 21. The AR coating film can be made up of, for example, a dielectric multilayer film. The anti-reflective layer 21 can be formed on the first surface 22a by chemical vapor deposition or physical vapor deposition.

[0036] The anti-reflective layer 21 may, for example, have light scattering properties. In this case, it is preferable that the anti-reflective layer 21 has a gloss of 0.3 or less.

[0037] As shown in Figure 3A, the anti-reflective layer 21 may be placed over the entire surface of the first surface 22a. Alternatively, as shown in Figure 3B, the anti-reflective layer 21 may be placed over a portion of the first surface 22a.

[0038] Specifically, the anti-reflective layer 21 may be arranged on the first surface 22a from the middle to the tip of each of the multiple prisms 22. In other words, the first surface 22a may have an exposed portion 22a1 and a non-exposed portion 22a2. The exposed portion 22a1 is located below the exposed portion 22a1 and further forward of the vehicle 2 than the non-exposed portion 22a2, extending from the middle of the first surface 22a to the lower end of the first surface 22a. The non-exposed portion 22a2 is located above the exposed portion 22a1 and extends from the middle of the first surface 22a to the tip of the prism 22. The exposed portion 22a1 is formed near the bottom of the valley formed by two adjacent prisms 22. In other words, the anti-reflective layer 21 is not arranged near the bottom of the valley.

[0039] The first surface 22a may be a flat surface as shown in Figure 3A, or it may be a concave free-form surface as shown in Figure 3C. When the first surface 22a is a concave free-form surface, the anti-reflective layer 21 laminated on the first surface 22a becomes less likely to peel off, and external light is less likely to enter the inside of the display device 10, thus reducing the generation of stray light.

[0040] As shown in Figures 2 and 3A, the second surface 22b faces the rear side of the vehicle 2 and extends along the vehicle width direction. In other words, the second surface 22b is the rear side of the vehicle 2 relative to the first surface 22a. The second surface 22b slopes downward from the front to the rear of the vehicle 2 relative to the surface 11a of the display element 11.

[0041] In such an in-vehicle display device 1, the display light emitted by the display element 11 passes through multiple prisms 22 in the optical body 20 and is emitted from the second surface 22b toward the windshield 3.

[0042] Although this embodiment has been described above, the following configuration is also included in this embodiment, as shown in Figures 4A and 4B, for example.

[0043] Figure 4A is a partially enlarged cross-sectional view showing a display element 11 such as a liquid crystal display and an optical body 20. Figure 4B is another partially enlarged cross-sectional view showing a display element 11 such as a liquid crystal display and an optical body 20.

[0044] For example, the display element 11 may be a liquid crystal display, an organic EL (Electro-Luminescence) display, or an LED display.

[0045] In this case, the optical body 20 may be attached to the surface 11a of the display element 11 via a filler 30 such as an optical clear adhesive (OCA) or optical clear resin (OCR). This fills the gap between the optical body 20 and the surface 11a of the display element 11, thereby suppressing the loss of display light.

[0046] Furthermore, the display device 10 may emit display light in a direction extending along the first surface 22a with respect to the normal direction of the surface 11a.

[0047] Specifically, as shown in Figure 4B, the display device 10 may further have a long backlight 40 that extends along the entire length of the vehicle 2. Since the display element 11 is arranged to extend along the entire length, the backlight 40 may be positioned with respect to the optical body 20 in a downward sloping position from the front side of the vehicle 2 to the rear side of the vehicle 2. In this case, an air layer 90 may be formed between the backlight 40 and the back surface of the display element 11. The backlight 40 may be the light-emitting module described above.

[0048] In this case, the optical axis direction of the light emitted from the backlight 40 is toward the display element 11 and intersects with the longitudinal direction of the backlight 40. In other words, the emission angle θ1 of the display light emitted from the display element 11 can be matched with the inclination angle θ2 of the anti-reflective layer 21 with respect to the normal to the surface 11a of the display element 11. As a result, the light emitted from the backlight 40 becomes display light via the display element 11, passes through the optical body 20 via the filler 30, and is emitted toward the windshield 3 from the second surface 22b.

[0049] Alternatively, the longitudinal direction of the backlight 40 and the back surface of the display element 11 may be arranged approximately parallel to each other. In this case, this can be achieved by placing a deflection element such as a prism element or a hologram element between the backlight 40 and the display element 11.

[0050] Furthermore, as shown in Figures 5A and 5B, the following configuration is also included in this embodiment.

[0051] Figure 5A is a schematic diagram showing the in-vehicle display device 1 and vehicle 2, which have a display device 10 using a light guide plate 51, as viewed from right to left. Figure 5B is a partially enlarged cross-sectional view showing the display device 10 using the light guide plate 51 and the optical body 20.

[0052] The display device 10 may include a light guide plate 51 and an image generation unit 52.

[0053] The light guide plate 51 may be a flat plate that is translucent and has a rectangular shape that is substantially parallel to the overall length and vehicle width direction.

[0054] The light guide plate 51 may have an incident surface 51a and a surface 51b that emits display light. Display light emitted from the image generation unit 52 is incident on the incident surface 51a. The incident surface 51a may face the image generation unit 52. The incident surface 51a may be a part of the back surface of the rectangular light guide plate 51. The surface 51b of the light guide plate 51 is the display light incident from the incident surface 51a, and the display light propagated inside the light guide plate 51 may be emitted towards the windshield 3. An optical body 20 may be placed on the surface 51b of the light guide plate 51. An air layer 90 may be formed between the light guide plate 51 and the optical body 20.

[0055] The image generation unit 52 may also emit display light. The display light emitted from the image generation unit 52 may be incident on a light guide, transmitted through it, and then emitted from the light guide to illuminate the windshield 3. As a result, the display light is reflected by the windshield 3, and the display light is projected onto the windshield 3, so that a virtual image can be perceived by the user. Such an image generation unit 52 may be realized by a display element 11, multiple emitters, multiple dichroic mirrors, a focusing lens, etc.

[0056] In this in-vehicle display device 1, the display light emitted from the surface 51b of the light guide plate 51 enters the back surface of the optical body 20 through the air layer 90. The incident display light passes through the optical body 20 and is emitted from the second surface 22b toward the windshield 3.

[0057] Furthermore, as shown in Figure 5C, the display device 10 may further include a light-transmitting optical medium 53 positioned between the light guide plate 51 and the optical body 20.

[0058] Figure 5C is a partially enlarged cross-sectional view showing the display device 10 and optical body 20 using the optical medium 53 and light guide plate 51.

[0059] The optical medium 53 may be a coupling layer for efficiently propagating the display light emitted from the surface 51b of the light guide plate 51 to the optical body 20. The optical medium 53 may have a gradually increasing thickness in the vertical direction from the front side of the vehicle 2 to the rear side of the vehicle 2. The optical body 20 may be arranged on the surface of the optical medium 53.

[0060] The light guide plate 51 may be positioned with respect to the optical body 20 in a downward sloping orientation from the front side of the vehicle 2 toward the rear side of the vehicle 2. An air layer 90 may be formed between the light guide plate 51 and the optical medium 53.

[0061] In this in-vehicle display device 1, the display light emitted from the surface 51b of the light guide plate 51 enters the back surface of the optical medium 53 via the air layer 90. The display light that enters the back surface of the optical medium 53 passes through the optical medium 53 and then through the optical body 20, and is emitted from the second surface 22b toward the windshield 3.

[0062] Furthermore, as shown in Figure 5C, the display light emitted from the second surface 22b may include a first-wavelength display light with a first wavelength and a second-wavelength display light with a second wavelength different from the first wavelength.

[0063] The light guide plate 51 may adjust the emission angles of the first wavelength indicator light and the second wavelength indicator light emitted from its surface 51b so that when emitted from the second surface 22b, the emission direction of the first wavelength indicator light and the emission direction of the second wavelength indicator light are substantially parallel.

[0064] Even in this case, an air layer 90 may be formed between the light guide plate 51 and the optical body 20.

[0065] In this in-vehicle display device 1, the display light emitted from the surface 51b of the light guide plate 51 enters the back surface of the optical body 20 through the air layer 90, passes through the optical body 20, and is emitted from the second surface 22b toward the windshield 3.

[0066] Furthermore, as shown in Figures 6A to 6C, the display device 10 may also include a screen 62 and a projector 61 that projects display light onto the screen 62.

[0067] Figure 6A is a schematic diagram showing the in-vehicle display device 1 and vehicle 2, which have a display device 10 using a projector 61, as viewed from right to left. Figure 6B is a partially enlarged cross-sectional view showing the display device 10 using the projector 61 and the optical body 20. Figure 6C is another partially enlarged cross-sectional view showing the display device 10 using the projector 61 and the optical body 20.

[0068] An optical body 20 may be placed on the surface 62b of the screen 62. The screen 62 and the optical body 20 may be integrally constructed. The screen 62 may have a light scattering function. Here, integral means that the screen 62 and the optical body 20 cannot be separated without destroying the screen 62 and the optical body 20.

[0069] Furthermore, as shown in Figure 6C, the display device 10 may further include an optical film 63 sandwiched between the screen 62 and the optical body 20. The optical film 63 may have a function for controlling the diffusion of the display light. For example, the optical film 63 can concentrate or spread light in a predetermined direction. The optical film 63 is, for example, a light control film.

[0070] In this in-vehicle display device 1, the display light emitted from the projector 61 enters the back surface of the screen 62, passes through the optical film 63, the screen 62, and the optical body 20, and is emitted from the second surface 22b toward the windshield 3.

[0071] <Effects and Effects> Next, the effects and advantages of the in-vehicle display device 1 in this embodiment will be described.

[0072] As described above, the in-vehicle display device 1 of Technology 1 according to this embodiment is an in-vehicle display device 1 that forms a virtual image by projecting display light onto a display medium of a vehicle 2, and comprises a display device 10 that displays a virtual image by emitting display light, and an optical body 20 disposed on the display device 10, the optical body 20 having a base and an anti-reflective layer 21, the base including a plurality of prisms 22 whose cross-section is triangular when cut by a plane perpendicular to the vehicle width direction of the vehicle 2, each of the plurality of prisms 22 having a first surface 22a facing the front side of the vehicle 2 and a second surface 22b facing the rear side of the vehicle 2, and the anti-reflective layer 21 is disposed on the first surface 22a.

[0073] According to this, since the anti-reflective layer 21 is placed on the first surface 22a facing the front of the vehicle 2, it is possible to suppress the reflection of incident ambient light. Therefore, it is possible to suppress the reflected ambient light from reaching the user's eye box.

[0074] Furthermore, since the anti-reflective layer 21 is arranged on the inclined first surface 22a, it is possible to suppress the obstruction of the emission of display light by the anti-reflective layer 21 compared to the conventional technology.

[0075] Therefore, this in-vehicle display device 1 can suppress the external light reflected by the in-vehicle display device 1 from reaching the user's eye box, and also suppress the obstruction of the display light.

[0076] In particular, in this embodiment, since the reflection of external light is suppressed by the base body and the anti-reflective layer 21, rather than employing multiple louvers as in the conventional technology, the risk of damage can be reduced compared to the conventional technology.

[0077] Furthermore, in the in-vehicle display device 1 of Technology 2 according to this embodiment, each of the multiple prisms 22 extends along the vehicle width direction.

[0078] According to this, the anti-reflective layer 21 will be placed on the front side of the vehicle 2, thereby suppressing the reflection of ambient light from the surface 11a.

[0079] Furthermore, in the in-vehicle display device 1 of Technology 3 according to this embodiment, the anti-reflective layer 21 is arranged on the first surface 22a, extending from the middle to the tip of each of the multiple prisms 22.

[0080] According to this, even if the anti-reflective layer 21 is not placed on the bottom side of the substrate, the incidence of ambient light can be suppressed. Furthermore, it is possible to prevent the anti-reflective layer 21 from protruding from the first surface 22a and obstructing the display light emitted from the second surface 22b of the adjacent prism 22.

[0081] Furthermore, in the in-vehicle display device 1 of Technology 4 according to this embodiment, the first surface 22a is a concave free-form surface.

[0082] According to this, the anti-reflective layer 21 is less likely to peel off from the first surface 22a. This prevents external light from entering the display device 10 and becoming stray light due to the peeling off of the anti-reflective layer 21.

[0083] Furthermore, in the in-vehicle display device 1 of Technology 5 according to this embodiment, the display device 10 has a display element 11, the display element 11 is a liquid crystal display, an organic EL display, or an LED display, and an optical body 20 is arranged on the surface 11a of the display element 11 that emits display light.

[0084] According to this, because of its superior resolution, it can form a clear virtual image and provide users with detailed information.

[0085] Furthermore, because it can emit high-brightness display light, it is easy for users to see even during the daytime. Therefore, this in-vehicle display device 1 has excellent visibility.

[0086] Furthermore, in the in-vehicle display device 1 of Technology 6 according to this embodiment, the display device 10 emits display light in a direction extending along the first surface 22a with respect to the normal direction of the surface 11a.

[0087] According to this, the direction of the display light emitted from the second surface 22b can be set to a desired direction. Therefore, the display light can be projected onto a desired location on the windshield 3, thereby forming a virtual image.

[0088] Furthermore, in the in-vehicle display device 1 of Technology 7 according to this embodiment, the display device 10 further has a long backlight 40 that extends along the overall length of the vehicle 2, the display element 11 is arranged to extend along the overall length, and the backlight 40 is arranged with respect to the display element 11 in a downward sloping position from the front side of the vehicle 2 toward the rear side of the vehicle 2.

[0089] This makes it easier to emit display light in a direction extending from the second surface 22b along the first surface 22a. As a result, display light can be projected onto a desired location on the windshield 3, thereby forming a virtual image.

[0090] Furthermore, in the in-vehicle display device 1 of Technology 8 according to this embodiment, the display device 10 includes a light guide plate 51 having an incident surface 51a and a surface 51b that emits display light, and an image generation unit 52 that causes display light to be incident on the incident surface 51a of the light guide plate 51. An optical body 20 is arranged on the surface 51b of the light guide plate 51, and an air layer 90 is formed between the light guide plate 51 and the optical body 20.

[0091] According to this, the surface 51b of the light guide plate 51 can emit display light with a uniform light distribution, and can also emit display light with high brightness, making it easier for users to see even in daylight. For this reason, this in-vehicle display device 1 has excellent visibility.

[0092] Furthermore, in the in-vehicle display device 1 of Technology 9 according to this embodiment, an optical medium 53 is further provided between the light guide plate 51 and the optical body 20, the optical body 20 is arranged to extend along the overall length direction of the vehicle 2, the optical body 20 is placed on the surface 51b of the optical medium 53, the thickness of the optical medium 53 gradually increases in the vertical direction from the front side of the vehicle 2 to the rear side of the vehicle 2, and the light guide plate 51 is arranged in a position that is inclined downward from the front side of the vehicle 2 to the rear side of the vehicle 2 with respect to the optical body 20.

[0093] According to this, when the display light emitted from the surface 51b of the light guide plate 51 is incident on the optical body 20 through the air layer 90, the optical medium 53 can reduce the incident angle of the display light. Therefore, it is possible to suppress a decrease in the utilization efficiency of the display light.

[0094] Furthermore, in the in-vehicle display device 1 of the technology 10 according to this embodiment, the display light emitted from the second surface 22b includes a first wavelength display light of the first wavelength and a second wavelength display light of a second wavelength different from the first wavelength, and the light guide plate 51 adjusts the emission angle of the first wavelength display light and the emission angle of the second wavelength display light emitted from the surface 51b of the light guide plate 51 so that when emitted from the second surface 22b, the emission direction of the first wavelength display light and the emission direction of the second wavelength display light are substantially parallel.

[0095] According to this, since the display light of each wavelength is uniformly emitted from the second surface 22b and projected onto the windshield 3, the user can easily see the virtual image formed on the windshield 3.

[0096] Furthermore, according to this embodiment, it is possible to suppress color separation or moiré phenomena that occur when colors overlap and are displayed. As a result, color consistency in the virtual image is maintained, and thus, visibility is expected to be improved.

[0097] Furthermore, in the in-vehicle display device 1 of the technology 11 according to this embodiment, the display device 10 has a screen 62 and a projector 61 that projects display light onto the screen 62, and an optical body 20 is arranged on the surface 62b of the screen 62.

[0098] This allows the display light to be projected onto the windshield 3 over a wide area. As a result, visual information can be displayed over a wide area in front of the user, making it easier for the user to intuitively grasp the information they need.

[0099] Furthermore, in the in-vehicle display device 1 of the technology 12 according to this embodiment, the screen 62 and the optical body 20 are integrally configured, and the screen 62 has a light scattering function.

[0100] According to this, since the screen 62 and the optical body 20 are integrally constructed, an increase in the number of parts can be suppressed.

[0101] Furthermore, the in-vehicle display device 1 of the technology 13 according to this embodiment further includes an optical film 63 sandwiched between the screen 62 and the optical body 20, and the optical film 63 has a function for controlling the diffusion of display light.

[0102] According to this, by placing the optical film 63 between the screen 62 and the optical body 20, it is possible to suppress the emission of display light from between the screen 62 and the optical body 20. Therefore, it is possible to suppress the display light from shining on another user.

[0103] (Other variations) Although the in-vehicle display device relating to this disclosure has been described above based on the embodiments described above, this disclosure is not limited to these embodiments. Various modifications to the embodiments that a person skilled in the art could conceive of may also be included in the scope of this disclosure, as long as they do not deviate from the spirit of this disclosure.

[0104] Furthermore, this disclosure also includes forms obtained by applying various modifications to the above embodiments that a person skilled in the art could conceive, and forms realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of this disclosure. [Industrial applicability]

[0105] The in-vehicle display device of this disclosure can be used as a head-up display mounted in a vehicle. [Explanation of Symbols]

[0106] 1 In-vehicle display device 2 vehicles 3. Windshield (Display medium) 10 Display device 11 Respect Display 11a Surface of the display element 20 Optical body 21 Anti-reflection layer 22 Prism (Base) 22a 1st page 22b 2nd side 40 Backlight 51 Light guide plate 51a Incidence plane 51b Surface of the light guide plate 52 Image Generation Unit 53 Optical media 61 Projector 62 screens 62b Screen surface 63 Optical Film 90 Air layer

Claims

1. An in-vehicle display device that forms a virtual image by projecting display light onto a vehicle's display medium, A display device that emits the aforementioned display light to display the virtual image, The display device comprises an optical body arranged in the display device, The optical material comprises a substrate and an anti-reflective layer. The base includes a plurality of prisms whose cross-section is triangular when cut by a plane perpendicular to the vehicle width direction of the vehicle. Each of the plurality of prisms has a first surface facing the front side of the vehicle and a second surface facing the rear side of the vehicle. The anti-reflective layer is disposed on the first surface. In-vehicle display device.

2. Each of the aforementioned prisms extends along the vehicle width direction. The in-vehicle display device according to claim 1.

3. The anti-reflective layer is arranged on the first surface, extending from the middle to the tip of each of the plurality of prisms. The in-vehicle display device according to claim 1.

4. The first surface is a concave freeform surface. The in-vehicle display device according to claim 1.

5. The display device has a display element, The display element is a liquid crystal display, an organic EL (Electro Luminescence) display, or an LED (Light Emitting Diode) display. The optical element is arranged on the surface of the display element from which the display light is emitted. The in-vehicle display device according to any one of claims 1 to 4.

6. The display device emits the display light in a direction extending along the first surface with respect to the normal direction of the surface. The in-vehicle display device according to claim 5.

7. The display device further has a long backlight that extends along the entire length of the vehicle. The display element is arranged to extend along the overall length direction, The backlight is positioned relative to the display element in a manner that causes it to slope downward from the front of the vehicle toward the rear of the vehicle. The in-vehicle display device according to claim 5.

8. The display device comprises a light guide plate having an incident surface and a surface from which the display light is emitted, and an image generation unit that causes the display light to be incident on the incident surface of the light guide plate. The optical element is arranged on the surface of the light guide plate. An air layer is formed between the light guide plate and the optical body. The in-vehicle display device according to any one of claims 1 to 4.

9. The optical medium is further disposed between the light guide plate and the optical body, The optical body is arranged to extend along the overall length of the vehicle, The optical material is arranged on the surface of the optical medium. The optical medium has a gradually increasing thickness in the vertical direction from the front side of the vehicle towards the rear side of the vehicle. The light guide plate is positioned relative to the optical body in a manner that it slopes downward from the front side of the vehicle toward the rear side of the vehicle. The in-vehicle display device according to claim 8.

10. The indicator light emitted from the second surface includes a first wavelength indicator light of the first wavelength and a second wavelength indicator light of a second wavelength different from the first wavelength. The light guide plate adjusts the emission angles of the first wavelength indicator light and the second wavelength indicator light emitted from the surface of the light guide plate so that when emitted from the second surface, the emission direction of the first wavelength indicator light and the emission direction of the second wavelength indicator light are substantially parallel. The in-vehicle display device according to claim 8.

11. The display device comprises a screen and a projector that projects the display light onto the screen. The optical element is arranged on the surface of the screen. The in-vehicle display device according to any one of claims 1 to 4.

12. The screen and the optical body are integrally constructed, The screen has a light scattering function. The in-vehicle display device according to claim 11.

13. The system further comprises an optical film sandwiched between the screen and the optical body, The optical film has a function for controlling the diffusion of the display light. The in-vehicle display device according to claim 11.

Images