Image display apparatus

Abstract

To provide an image display device for a vehicle in which an image generation part hardly becomes high in temperature.SOLUTION: The HUD2 is mounted in the vehicle 1 and displays an image as a virtual image to an occupant. An HUD2 includes an image generation part 24 having an emission surface 243 for emitting light for generating an image, and a housing 22 for storing the emission surface 243 inside. The upper side 22U of the housing 22 has an upper front part 222 provided with a window 23 through which light from the image generator 24 is emitted to the outside, and an upper rear part 223 that covers the upper side of at least a part of the image generator 24. At least a part of the upper rear portion 223 is provided with a heat shielding portion 224 that suppresses heat transfer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an image display device. [Background technology]

[0002] Patent Document 1 discloses a head-up display (HUD) as an example of an image display device. The image generating device of the HUD in Patent Document 1 is provided with a heat insulating member between a light source unit and an image generating unit, the heat insulating member having a light-transmitting, low-thermal conductivity portion with lower thermal conductivity than air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-098237 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a vehicle is parked on a sunny summer day, the interior of the vehicle can reach high temperatures due to heat from sunlight. However, image display devices contain electronic components, such as an image generation unit, that are relatively susceptible to heat, so there is still room for improvement in measures to deal with heat when using image display devices.

[0005] An object of the present disclosure is to provide an image display device for a vehicle in which an image generating unit is less likely to become hot. [Means for solving the problem]

[0006] An image display device according to one aspect of the present disclosure includes: An image display device that is mounted on a vehicle and displays an image as a virtual image to a passenger, an image generating unit having an exit surface that emits light for generating the image; a housing that accommodates the light exit surface therein, The upper part of the housing is a first section provided with a window section for emitting light from the image generating section to the outside; a second portion covering at least a portion of the image generating portion; At least a part of the second portion is provided with a heat shield portion for suppressing heat transfer.

[0007] The housing of the present disclosure has a second part that covers at least a part of the image generation part from above, and a heat shield is provided on at least a part of the second part. Therefore, the heat shield blocks heat transmitted from a heat source located above the image generation part, such as a hot dashboard, and the image generation part can be prevented from becoming too hot. [Effects of the Invention]

[0008] According to the present disclosure, an image display device for a vehicle in which an image generating unit is less likely to become hot is provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a HUD according to a first embodiment provided in a vehicle, viewed from the side of the vehicle. [Figure 2] FIG. 2 is a schematic diagram of the HUD in FIG. 1 as seen from above the vehicle. [Figure 3] FIG. 3 is a schematic diagram of a HUD according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For the sake of convenience, descriptions of components having the same reference numerals as those already described in the description of the embodiments will be omitted. Furthermore, for the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0011] In addition, for the sake of convenience, in the description of this embodiment, the terms "left-right direction," "up-down direction," and "front-rear direction" may be referred to as appropriate. These directions are relative directions set for the head-up display (HUD) 2 shown in FIG. 1 . Here, the "left-right direction" refers to a direction including a "left direction L" and a "right direction R." The "up-down direction" refers to a direction including an "upward direction U" and a "downward direction D." The up-down direction is also the vertical direction. The "front-rear direction" refers to a direction including a "forward direction F" and a "rearward direction B." The front-rear direction in the HUD 2 coincides with the front-rear direction in the vehicle 1. Here, the traveling direction of the vehicle 1 is defined as the forward direction. Although not shown in FIG. 1 , the left-right direction refers to a direction perpendicular to the up-down direction and the front-rear direction. The left-right direction also corresponds to the width direction of the vehicle 1. The HUD 2 is an example of an image display device.

[0012] (First embodiment) FIG. 1 is a schematic diagram of a HUD 2 according to a first embodiment provided in a vehicle 1, viewed from the side of the vehicle 1. The HUD 2 is mounted on the vehicle 1 and configured to project a virtual image onto the windshield WS so as to be superimposed on the scenery ahead of the vehicle. At least a portion of the HUD 2 is located inside the vehicle 1. Specifically, the HUD 2 is installed in a dashboard DB of the vehicle 1.

[0013] As shown in FIG. 1, the HUD 2 includes a HUD main body 20. The HUD main body 20 has a housing 22 and a window 23. The HUD main body 20 has an image generation unit (PGU) 24, a first concave mirror 26, and a second concave mirror 28 inside the housing 22. The housing 22 is made of a light-blocking resin material. The image generation unit 24, which will be described later, is disposed in the internal space formed by the housing 22. The window 23 is provided in an upper portion 22U of the housing 22. The window 23 is closed by a transparent plate that transmits visible light.

[0014] The image generating unit 24 includes a light source (not shown) provided on a substrate 241, a lens 242, and an exit surface 243. The light source is, for example, a laser light source or an LED light source. The lens 242 guides the light emitted from the light source toward the exit surface 243.

[0015] The light exit surface 243 is accommodated inside the housing 22. The light exit surface 243 is configured to emit light emitted from the light source as light for generating an image. The light exiting the light exit surface 243 is guided to the first concave mirror 26.

[0016] The first concave mirror 26 and the second concave mirror 28 are disposed on the optical path of the light emitted from the image generator 24. The first concave mirror 26 is disposed above the image generator 24 inside the housing 22. The first concave mirror 26 is configured to reflect the light emitted from the emission surface 243 of the image generator 24 toward the second concave mirror 28. The second concave mirror 28 is disposed forward of the first concave mirror 26 and the image generator 24 inside the housing 22. The second concave mirror 28 is configured to reflect the light reflected by the first concave mirror 26 toward the windshield WS via the window 23. The second concave mirror 28 has a concavely curved reflective surface and reflects the image of the light emitted from the image generator 24 and formed at a predetermined magnification.

[0017] Light emitted from the window 23 of the HUD main body 20 is irradiated onto the windshield WS. A portion of the light irradiated from the HUD main body 20 onto the windshield WS is reflected toward the occupant's viewpoint. As a result, the occupant perceives the light (predetermined image) emitted from the HUD main body 20 as a virtual image formed at a predetermined distance in front of the windshield WS. In this way, the virtual image displayed by the HUD 2 is superimposed on the real space in front of the vehicle 1 through the windshield WS, allowing the occupant to visually perceive the virtual object as floating above the road outside the vehicle.

[0018] Next, the housing 22 will be described in detail with reference to FIGS.

[0019] FIG. 2 is a schematic diagram of the HUD 2 as viewed from above the vehicle 1. As shown in FIG. 2, the upper portion 22U of the housing 22 is composed of an upper front portion 222 and an upper rear portion 223 located rearward of the upper front portion 222. The upper front portion 222 is provided with a window portion 23. The upper front portion 222 is a frame-shaped portion that forms the window portion 23. The upper front portion 222 is configured to cover at least a portion of the image generation unit 24 from above, in a top view. The upper front portion 222 is an example of a first portion. The upper rear portion 223 is an example of a second portion.

[0020] The upper rear portion 223 of the housing 22 is composed of a design surface portion 225 and a hidden surface portion 226. The design surface portion 225 is a portion that is exposed to the outside when the HUD 2 is mounted on the vehicle 1. An opening O that exposes the window portion 23 is provided on the top surface of the dashboard DB. The design surface portion 225 is the portion of the upper rear portion 223 of the housing 22 that is exposed to the outside through the opening O of the dashboard DB. In the illustrated example, the design surface portion 225 occupies approximately one-third of the area of ​​the upper rear portion 223 of the housing 22.

[0021] The hidden surface portion 226 is a portion that is not exposed to the outside when the HUD 2 is mounted on the vehicle 1. The hidden surface portion 226 is located rearward of the design surface portion 225. The hidden surface portion 226 is covered by the dashboard DB located above the hidden surface portion 226.

[0022] 1, above the image generating unit 24, a portion of the dashboard DB that forms the opening O is close to the decorative surface portion 225 and the hidden surface portion 226 of the housing 22. When the dashboard DB becomes hot due to sunlight, the heat of the dashboard DB may be transferred to the decorative surface portion 225 and the hidden surface portion 226. As a result, heat is transferred from the decorative surface portion 225 and the hidden surface portion 226 to the image generating unit 24, and the image generating unit 24 is likely to become hot.

[0023] Therefore, in the HUD 2 of this embodiment, a heat shield 224 that suppresses heat transfer is provided in at least a part of the upper rear part 223. In a top view, the heat shield 224 is provided in the upper part 22U of the housing 22 at a position that overlaps with at least a part of the image generation unit 24.

[0024] Therefore, according to the HUD2 of this embodiment, the heat transmitted from a heat source located above the image generation unit 24, such as a hot dashboard DB, is blocked by the heat shielding portion 224, thereby preventing the image generation unit 24 from becoming too hot.

[0025] The heat shield 224 is provided on the outer surface 226a of the hidden surface portion 226. The heat shield 224 is provided so as to follow the outer shape of the hidden surface portion 226. The heat insulating property of the heat shield 224 is higher than that of the decorative surface portion 225. The heat shield 224 may be formed, for example, from a heat insulating material. Examples of the heat insulating material include organic or inorganic porous bodies (styrofoam or pumice), rubber or resin materials with low thermal conductivity, and ceramics. The heat shield 224 may be formed by attaching or forming a film of these materials as a sheet or film on the outer surface 226a of the hidden surface portion 226, or by forming a part of the hidden surface portion 226 with these materials.

[0026] When the HUD 2 operates, the image generation unit 24 generates heat. The image generation unit 24 is composed of electronic components and therefore should be cooled. However, as shown in FIG. 1 , the image generation unit 24 is located above and close to the design surface portion 225 and hidden surface portion 226 of the housing 22. Heat from the dashboard DB may be transferred to the design surface portion 225 and hidden surface portion 226. Since the design surface portion 225 and hidden surface portion 226 located above the image generation unit 24 are hot, the air heated by the image generation unit 24 is not carried upward by convection and tends to remain around the image generation unit 24, making it difficult for the image generation unit 24 to dissipate heat. Thus, in a HUD 2 provided below the dashboard DB, heat dissipation from the image generation unit 24 is likely to be insufficient. However, according to this embodiment, the heat shield 224 prevents heat from the dashboard DB from being transferred to the design surface portion 225 and hidden surface portion 226, making it easier for the image generation unit 24 to dissipate heat by convection.

[0027] In this embodiment, the upper rear portion 223 has a design surface portion 225 that is exposed to the outside when mounted on the vehicle 1, and a hidden surface portion 226 that is not exposed. The hidden surface portion 226 that is not exposed to the outside is covered by the dashboard DB, and therefore heat is easily transferred from the heated dashboard DB. Furthermore, because the HUD 2 is mounted in a limited space in the vehicle 1, the hidden surface portion 226 is disposed relatively close to the dashboard DB. Therefore, the space between the dashboard DB and the hidden surface portion 226 is relatively narrow, and heat is easily trapped.

[0028] However, in this embodiment, heat shield 224 is provided on outer surface 226a of hidden surface portion 226, which is prone to trapping heat, and therefore a rise in temperature of hidden surface portion 226 is suppressed. As a result, air heated by image generation unit 24 tends to rise from hidden surface portion 226, which tends to become hot, to image generation unit 24, making it easy to suppress heat transfer from hidden surface portion 226 to image generation unit 24. Furthermore, the temperature around hidden surface portion 226, which is located above image generation unit 24, is less likely to rise, and air heated by image generation unit 24 tends to rise, making it easier for image generation unit 24 to dissipate heat by convection.

[0029] The HUD 2 may further include a heat dissipation unit 29. The heat dissipation unit 29 is provided in the lower portion 22D of the housing 22, near the image generation unit 24. An upper end 29U of the heat dissipation unit 29 is located lower than an upper end 224U of the heat shield 224. The heat dissipation unit 29 can be configured, for example, with a plurality of plate-shaped fins extending in the front-rear and up-down directions.

[0030] 2, in a top view, at least a portion of heat dissipation section 29 overlaps with heat shielding section 224. Above heat dissipation section 29, there is a portion that is less likely to become hot due to heat shielding section 224. Therefore, air heated by heat dissipation section 29 tends to rise, and the cooling efficiency of heat dissipation section 29 is improved.

[0031] Heat shield 224 may be provided in upper portion 22U of housing 22 facing exit surface 243 of image generation unit 24. Of the heat transferred by radiation from upper portion 22U of housing 22 to exit surface 243 of image generation unit 24, the heat transferred by radiation from a portion of upper portion 22U of housing 22 directly facing exit surface 243 is large. In this embodiment, heat shield 224 is provided at a position directly facing exit surface 243, so that heat transfer to the exit surface can be effectively suppressed.

[0032] The position where heat shield 224 is provided is not limited to outer surface 226a of hidden surface portion 226. Heat shield 224 may be provided on the inner surface of hidden surface portion 226 instead of outer surface 226a of hidden surface portion 226. Alternatively, hidden surface portion 226 itself may be formed from a heat insulating material.

[0033] Second Embodiment Fig. 3 is a schematic diagram of a HUD 2A according to the second embodiment. In the configuration shown in Fig. 3, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0034] As shown in FIG. 3 , in this embodiment, the heat shield 224A includes an outer wall 227 having an air intake 228a and an exhaust 228b, and an inner wall 229 that defines a flow path 228 extending from the air intake 228a to the exhaust 228b between the outer wall 227 and the inner wall 229. In the illustrated example, the heat shield 224A is a separate component provided on the outside of the housing 22. The flow path 228 is formed between the heat shield 224A and the housing 22. The air intake 228a is provided at a lower part of the flow path 228, and the exhaust 228b is provided at an upper part of the flow path 228. The air intake 228a is located above the heat dissipation portion 29 of the HUD 2A and opens downward. The exhaust 228b opens into the space between the hidden surface 226 and the upper surface of the dashboard DB. The outer wall 227 is formed of a heat-insulating material.

[0035] According to the present embodiment, a flow path 228, which is an air layer, is formed between the heat shield 224A and the housing 22. Therefore, the heat transferred from the high-temperature dashboard DB is blocked by the flow path 228, and it is possible to prevent the image generation unit 24 from becoming too hot.

[0036] Furthermore, unlike this embodiment, if outer wall portion 227 were not made of a heat-insulating material, the inside of flow path 228 would become hot due to the high temperature of dashboard DB, and the air warmed by heat dissipation portion 29 would not be able to be taken into flow path 228. However, according to this embodiment, outer wall portion 227, which forms part of flow path 228, is made of a heat-insulating material, so the temperature inside flow path 228 can be kept lower than the temperature of the space between dashboard DB and hidden surface portion 226. The air warmed by heat dissipation portion 29 rises and enters the flow path from intake port 228a, allowing heat dissipation portion 29 to efficiently dissipate heat.

[0037] Although the embodiments of the present disclosure have been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the disclosure described in the claims. The technical scope of the present disclosure should be determined based on the scope of the disclosure described in the claims and its equivalents.

[0038] The configurations described in each item listed below also constitute part of this disclosure. Item 1: An image display device that is mounted on a vehicle and displays an image as a virtual image to a passenger, an image generating unit having an exit surface that emits light for generating the image; a housing that accommodates the light exit surface therein, The upper part of the housing is a first section provided with a window section for emitting light from the image generating section to the outside; a second portion covering at least a portion of the image generating portion; An image display device, wherein a heat shield for suppressing heat transfer is provided in at least a part of the second section. Item 2: The image display device described in item 1, wherein the second part of the housing has a decorative surface portion that is exposed to the outside when mounted on the vehicle and a hidden surface portion that is not exposed, and the outer surface or inner surface of the hidden surface portion or the hidden surface itself is the heat-shielding portion with higher thermal insulation properties than the decorative surface portion. Item 3: The image display device further includes a heat dissipation unit, an upper end of the heat dissipation portion is located lower than an upper end of the heat shield portion; 3. The image display device according to item 1 or 2, wherein at least a portion of the heat dissipation portion overlaps with the heat shielding portion in a top view. Item 4: 4. The image display device according to any one of items 1 to 3, wherein the heat shield is provided on the upper part of the housing facing the light exit surface. Item 5: 5. The image display device according to any one of items 1 to 4, wherein the heat shield is formed of a heat insulating material. Item 6: 6. The image display device according to any one of items 1 to 5, wherein the heat shielding portion has an outer wall portion having an air intake port and an exhaust port, and an inner wall portion that forms a flow path extending from the air intake port to the exhaust port between the outer wall portion and the inner wall portion. Item 7: An image display device that is mounted on a vehicle and displays an image as a virtual image to a vehicle occupant, an image generating unit having an exit surface that emits light for generating the image; a housing that accommodates the light exit surface therein, An image display device, wherein a heat shield for suppressing heat transfer is provided in an upper portion of the housing at a position overlapping at least a part of the image generation unit in a top view. [Explanation of symbols]

[0039] 1 vehicle 2,2A HUD (Head-Up Display) 20 HUD main body 22 Housing 22U top 22D lower 224U top end 222 Upper front 223 Upper rear 224,224A Heat shield 225 Design surface section 226 Hidden Face 226a Exterior 227 Exterior wall 228 Channel 228a Air intake 228b Exhaust port 229 Inner wall 23 Window 24 Image generation unit 241 PCB 242 Lens 243 Exit Surface 26 First concave mirror 28 Second concave mirror 29 Heat-generating section 29U top

Claims

1. An image display device that is mounted on a vehicle and displays an image as a virtual image to a passenger, an image generating unit having an exit surface that emits light for generating the image; a housing that accommodates the light exit surface therein, The upper part of the housing is a first section provided with a window section for emitting light from the image generating section to the outside; a second portion covering at least a portion of the image generating portion; An image display device, wherein a heat shield for suppressing heat transfer is provided in at least a part of the second section.

2. 2. The image display device according to claim 1, wherein the second part of the housing has a decorative surface portion that is exposed to the outside when mounted on the vehicle and a hidden surface portion that is not exposed, and the outer surface or inner surface of the hidden surface portion or the hidden surface itself is the heat-shielding portion that has higher insulating properties than the decorative surface portion.

3. The image display device further includes a heat dissipation unit, an upper end of the heat dissipation portion is located lower than an upper end of the heat shield portion; The image display device according to claim 1 , wherein at least a portion of the heat dissipation portion overlaps with the heat shielding portion in a top view.

4. The image display device according to claim 1 , wherein the heat shield is provided on the upper part of the housing facing the light exit surface.

5. The image display device according to claim 1 , wherein the heat shield is made of a heat insulating material.

6. The image display device according to claim 1 , wherein the heat shielding portion has an outer wall portion having an air intake port and an air exhaust port, and an inner wall portion that forms a flow path extending from the air intake port to the air exhaust port between the outer wall portion and the inner wall portion.

Images