Image display device

Abstract

This image display device (100) comprises: a metal housing (10) in which an opening (10a) is formed in an upper wall (11a) and which accommodates a light source that emits light toward the opening (10a); a liquid crystal display unit (20) that is disposed at a position blocking the opening (10a) and outputs light from the light source as display light (L) of an image; a glass plate (60) that is disposed between the opening of the housing and the liquid crystal display unit, is in contact with the liquid crystal display unit, and transmits light from the light source to the liquid crystal display unit side; and a heat conduction sheet (80) that is disposed between the edge of the opening in the housing and the edge of the glass plate, receives the heat of the liquid crystal display unit via the glass plate, and transfers the heat to the housing.

Description

Image display device

[0001] The present invention relates to an image display device.

[0002] For example, Patent Document 1 discloses a configuration in which a display constituting a head-up display device includes a backlight, a liquid crystal panel, and a rear light-transmitting plate. In this display, the rear light-transmitting plate is a transparent glass plate that is placed in contact with the back side of the liquid crystal panel, and one side is roughened by wet blasting. The roughened side of this rear light-transmitting plate is placed so as to overlap the liquid crystal panel as the panel-facing surface. In addition, the surface roughness of the panel-facing surface is set to a value that is sufficiently fine relative to the size of the liquid crystal panel and the angle of view at which a virtual image can be displayed. Patent Document 1 claims that the above configuration can improve the heat dissipation of the display while suppressing the occurrence of interference fringes.

[0003] Japanese Patent Application Laid-Open No. 2023-66232

[0004] Incidentally, in image display devices used in head-up displays and the like, it is desirable to improve heat dissipation and vibration resistance.

[0005] An object of the present invention is to provide an image display device that can improve heat dissipation performance and vibration resistance.

[0006] The image display device of the present invention comprises a metal housing having an opening formed in the upper wall and accommodating a light source that irradiates light toward the opening; a liquid crystal display unit that is positioned to cover the opening and emits light from the light source as light for displaying an image; a glass plate that is positioned between the opening in the housing and the liquid crystal display unit, is in contact with the liquid crystal display unit, and transmits light from the light source toward the liquid crystal display unit; and a heat conduction sheet that is positioned between the edge of the opening in the housing and the edge of the glass plate, receives heat from the liquid crystal display unit through the glass plate, and transfers it to the housing.

[0007] The image display device according to the present invention has the advantage of being able to improve heat dissipation performance and vibration resistance performance.

[0008] FIG. 1 is a schematic diagram showing a vehicle display device including an image display device according to an embodiment. FIG. 2 is a perspective view showing an image display device according to an embodiment. FIG. 3 is an exploded perspective view showing an image display device according to an embodiment. FIG. 4 is a top view showing a housing of the image display device according to an embodiment. FIG. 5 is a top view showing an image display device according to an embodiment. FIG. 6 is a top view showing an image display device according to an embodiment. FIG. 7 is a top view showing an image display device according to an embodiment. FIG. 8 is a perspective view showing an image display device according to an embodiment. FIG. 9 is a cross-sectional view showing an image display device according to an embodiment. FIG. 10 is an enlarged cross-sectional view showing an image display device according to an embodiment. FIG. 11 is an enlarged cross-sectional view showing an image display device according to an embodiment. FIG. 12 is a cross-sectional view showing an image display device according to an embodiment. FIG. 13 is an enlarged cross-sectional view showing an image display device according to an embodiment. FIG. 14 is an enlarged cross-sectional view showing an image display device according to an embodiment. FIG. 15 is an enlarged cross-sectional view showing an image display device according to an embodiment.

[0009] An image display device according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiment. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art or those that are substantially the same.

[0010] [Embodiments] An embodiment will be described with reference to Fig. 1 to Fig. 15. Fig. 1 is a schematic diagram showing a vehicle display device including an image display device according to an embodiment, Fig. 2 is a perspective view showing an image display device according to an embodiment, Fig. 3 is an exploded perspective view showing an image display device according to an embodiment, Fig. 4 is a top view showing a housing of the image display device according to an embodiment, Fig. 5 is a top view showing an image display device according to an embodiment, Fig. 6 is a top view showing an image display device according to an embodiment, Fig. 7 is a top view showing an image display device according to an embodiment, Fig. 8 is a perspective view showing an image display device according to an embodiment, Fig. 9 is a cross-sectional view showing an image display device according to an embodiment, Fig. 10 is an enlarged cross-sectional view showing an image display device according to an embodiment, Fig. 11 is an enlarged cross-sectional view showing an image display device according to an embodiment, Fig. 12 is a cross-sectional view showing an image display device according to an embodiment, Fig. 13 is an enlarged cross-sectional view showing an image display device according to an embodiment, Fig. 14 is an enlarged cross-sectional view showing an image display device according to an embodiment, and Fig. 15 is an enlarged cross-sectional view showing an image display device according to an embodiment.

[0011] In Fig. 5, the liquid crystal display unit, flexible printed circuit board, glass plate, elastic member, and bezel are omitted for the sake of explanation. In Fig. 6, the liquid crystal display unit, flexible printed circuit board, elastic member, and bezel are omitted for the sake of explanation. In Figs. 7 and 8, the elastic member and bezel are omitted for the sake of explanation. In Fig. 9, a cross-sectional view is shown along line A-A in Fig. 2, Fig. 10 is an enlarged cross-sectional view of region A1 shown in Fig. 9, and Fig. 11 is an enlarged cross-sectional view of region A2 shown in Fig. 9. In Fig. 12, a cross-sectional view is shown along line B-B in Fig. 2, Fig. 13 is an enlarged cross-sectional view of region C in Fig. 12, Fig. 14 is an enlarged cross-sectional view of the glass plate and its periphery along line C-C in Fig. 2, and Fig. 15 is an enlarged cross-sectional view of the glass plate and its periphery along line D-D in Fig. 2.

[0012] 1, an image display device 100 according to the embodiment is a display device that emits display light L of an image, and is applied to a vehicle display device 200 that is mounted on a vehicle 300 such as an automobile. The vehicle display device 200 according to the embodiment is a head-up display device.

[0013] The vehicle display device 200 is disposed inside the dashboard of the vehicle 300 and emits display light L toward a reflective surface of a display member 301 of the vehicle 300. The display member 301 in the embodiment is a windshield. In the embodiment, the display member 301 is disposed in front of the driver of the vehicle 300. The reflective surface of the display member 301 may be coated with a semi-transparent coating or the like that reflects part of the incident light and transmits other part of the light. The display light L emitted toward the reflective surface of the display member 301 is reflected from the reflective surface to the eye point EP of the vehicle 300 and is visually recognized as a virtual image by the driver.

[0014] The vehicle display device 200 is configured to include the image display device 100 according to the embodiment. In the embodiment, the vehicle display device 200 includes a case 201, a first reflecting member 202, and a second reflecting member 203 in addition to the image display device 100.

[0015] The case 201 accommodates and supports the first reflecting member 202, the second reflecting member 203, and the image display device 100. The case 201 has an opening 201a that communicates between the inside and outside of the case 201. The opening 201a is provided in the case 201 at a position facing the display member 301. The vehicle display device 200 emits display light L from the case 201 toward the display member 301 through the opening 201a. The display light L is light that is emitted from the image display device 100 and reflected by the first reflecting member 202 and the second reflecting member 203.

[0016] The first reflecting member 202 and the second reflecting member 203 are disposed on the optical path from the image display device 100 to the display member 301, and are an optical system that reflects the display light L emitted from the image display device 100 toward the display member 301. The first reflecting member 202 has a flat reflecting surface and is disposed at a position facing the image display device 100. The first reflecting member 202 reflects the display light L emitted from the image display device 100 toward the second reflecting member 203. The second reflecting member 203 has a concave curved reflecting surface and is disposed at a position facing the first reflecting member 202. The second reflecting member 203 reflects the display light L reflected by the first reflecting member 202 toward the display member 301 through the opening 201 a. In the embodiment, the second reflecting member 203 functions as a magnifying mirror. That is, the second reflecting member 203 enlarges and reflects the display image so that the display image represented by the display light L after being reflected by the second reflecting member 203 is larger than the display image represented by the display light L before being reflected by the second reflecting member 203.

[0017] The image display device 100 shown in Fig. 2 emits a display image projected onto a display member 301 as display light L. As shown in Fig. 3, the image display device 100 according to the embodiment includes a housing 10, a liquid crystal display unit 20, a bezel unit 30, a flexible printed circuit board unit 40, an elastic member 50, a glass plate 60, a diffusion plate 70, and a heat conduction sheet 80.

[0018] The housing 10 is a box-shaped member that houses a light source (not shown) therein. The light source is, for example, an LED (Light Emitting Diode) mounted on a substrate or the like. The housing 10 in this embodiment is a metal housing. The housing 10 is formed of a metal material with high thermal conductivity, such as aluminum. In this embodiment, the housing 10 is composed of an upper housing 11 and a lower housing 12.

[0019] The upper housing 11 includes a rectangular plate-shaped top wall 11a and side walls 11b extending vertically from each side of the top wall 11a, and is formed in a box shape with an open bottom. The lower housing 12 includes a rectangular plate-shaped bottom wall 12a and side walls 12b extending vertically from each side of the bottom wall 12a, and is formed in a box shape with an open top.

[0020] The housing 10 is formed into a box shape by assembling the upper housing 11 and the lower housing 12 so that the lower opening of the upper housing 11 and the lower housing 12 are aligned with each other, and are fixed with fixing members such as screws. １ , second side wall 11b ２ , third side wall 11b ３ , and the fourth side wall 11b ４ In the upper housing 11, the first side wall 11b １ and the second side wall 11b ２ The third side wall 11b faces each other in the front-rear direction perpendicular to the up-down direction from the upper housing 11 to the lower housing 12. ３ and the fourth side wall 11b ４ The two plates face each other in the width direction perpendicular to the up-down direction and the front-rear direction.

[0021] The upper wall 11a is connected to the first side wall 11b. １ to the second side wall 11b ２ The third side wall 11b is disposed so as to slope downward. ３ the upper end of the fourth side wall 11b ４ The upper ends of the first side walls 11b are aligned with the upper wall 11a. １ From the side, the second side wall 11b ２ Here, the lower side in the vertical direction is the side of the lower housing 12 relative to the upper housing 11, and the upper side in the vertical direction is the side of the upper housing 11 relative to the lower housing 12.

[0022] In the embodiment, the first side wall 11b in the vertical direction １ , second side wall 11b ２ , third side wall 11b ３ , and the fourth side wall 11b ４The positions of the lower ends of the first side walls 11b are located at substantially the same position. １ The length of the second side wall 11b in the vertical direction is ２ The upper ends of the four side walls of the lower housing 12 are located at substantially the same positions in the up-down direction.

[0023] An opening 10a is formed in the upper wall 11a of the housing 10. In this embodiment, the opening 10a is formed in a rectangular shape with the short side extending in the front-to-rear direction and the long side extending in the width direction. A light source housed in the housing 10 is arranged to irradiate light toward the opening 10a.

[0024] 3, a heat dissipation member 12A is formed on the bottom wall 12a of the housing 10. The heat dissipation member 12A protrudes from the bottom wall 12a of the lower housing 12 toward the side opposite to the upper housing 11 (i.e., downward). The heat dissipation member 12A in this embodiment is made up of a plurality of plate-like portions protruding downward from the bottom wall 12a of the lower housing 12, and functions as heat dissipation fins.

[0025] Furthermore, flange portions 12B are formed on the lower housing 12 for fixing the image display device 100 to a case 201 (see FIG. 1 ) of the vehicle display device 200. The flange portions 12B in the embodiment are formed on both side walls of the lower housing 12 in the width direction. In the embodiment, the flange portions 12B are formed as plate-like portions that protrude in the width direction from the side walls of the lower housing 12. Each flange portion 12B has an insertion hole formed therein through which a fastening member such as a bolt is inserted.

[0026] As shown in Fig. 4, a groove 11c is formed at the edge of the opening 10a in the top wall 11a of the housing 10. Here, the "edge of the opening 10a" refers to the portion surrounding the hole of the opening 10a in the top wall 11a. The groove 11c is formed in a shape that is recessed downward relative to the surrounding surface at the edge of the opening 10a. As shown in Fig. 5, a heat conduction sheet 80 is placed inside the groove 11c. In this embodiment, the groove 11c is a first groove 11c. １ and the second groove portion 11c ２The first groove portion 11c １ and the second groove portion 11c ２ The first groove portion 11c is formed at a position sandwiching the opening 10a in the front-rear direction (the short side direction of the opening 10a). １ The first side wall 11b is spaced apart from the opening 10a. １ The second groove portion 11c is located on the side of the ２ The second side wall 11b is spaced apart from the opening 10a. ２ The first groove portion 11c is located on the side of the first groove portion 11c. １ and the second groove portion 11c ２ is formed as a rectangular groove extending along the width direction (longitudinal direction of the opening 10a).

[0027] As shown in FIG. 3 , the liquid crystal display unit 20 is a so-called liquid crystal panel, and is configured, for example, by a light-transmitting or light-semitransmitting TFT liquid crystal (Thin Film Transistor Liquid Crystal Display). The liquid crystal display unit 20 emits light from its display surface on the front side when illuminated by a light source from the rear side. With this configuration, the liquid crystal display unit 20 emits light from the light source as image display light L from the display surface. Here, the light source is driven by power obtained from, for example, a battery in the vehicle 300 (see FIG. 1 ). In this embodiment, the liquid crystal display unit 20 is formed in the shape of a rectangular plate slightly larger than the opening 10 a of the housing 10 and is positioned to cover the opening 10 a.

[0028] The bezel 30 is disposed above the top wall 11a of the housing 10. The bezel 30 has an opening 30a that is rectangular when viewed from the top-bottom direction. The opening 30a of the bezel 30 is a portion through which display light L from the liquid crystal display unit 20 passes toward the first reflecting member 202 (see FIG. 1 ). In the embodiment, the bezel 30 is formed in a frame shape that follows the edge of the opening 10a of the housing 10. The bezel 30 is fixed to the housing 10 with the liquid crystal display unit 20 sandwiched between the bezel 30 and the edge of the opening 10a of the housing 10.

[0029] In this embodiment, as shown in FIG. 2, the third side wall 11b of the upper housing 11 ３ and the fourth side wall 11b ４The bezel 30 has a protrusion 11A that protrudes outward, and the bezel 30 has a locking portion 31 that engages with the protrusion 11A. The locking portions 31 are provided as a plurality of frame-shaped portions, each of which protrudes from the outer periphery of the bezel 30 toward the housing 10 and is arranged to correspond one-to-one with the protrusion 11A. The bezel 30 is attached to the housing 10 from above in the up-down direction. When the bezel 30 is attached to the housing 10, the locking portions 31 climb over the protrusions 11A and fit the protrusions 11A into the frames of the locking portions 31, thereby locking the bezel 30 to the housing 10.

[0030] The flexible printed circuit board unit 40 includes a display control unit 41 and a flexible film-like wiring unit 42. The display control unit 41 in this embodiment is a rectangular plate-like member made of, for example, an IC chip, and is provided on the surface of the wiring unit 42 and electrically connected to the wiring unit 42. In this embodiment, an end of the flexible printed circuit board unit 40 (one end of the wiring unit 42) is connected to a first display edge 20a, which is one of the four sides of the liquid crystal display unit 20. Here, the first display edge 20a is connected to the first side wall 11b. １ The display control unit 41 is driven by power obtained from a battery or the like in the vehicle 300, and controls the operation of the liquid crystal display unit 20 connected via the wiring unit 42.

[0031] The elastic member 50 is a rubber-like or sponge-like member provided between the bezel 30 and the liquid crystal display 20. The elastic member 50 is, for example, a packing. In the embodiment, the elastic member 50 includes a first elastic member 51 and a second elastic member 52.

[0032] The first elastic member 51 and the second elastic member 52 are each formed in a thin plate or rod shape. The first elastic member 51 is attached to one side of the liquid crystal display unit 20 in the extending direction of the first display edge 20a (the third side wall 11b). ３ The second elastic member 52 is disposed on the other end (fourth side wall 11b) of the liquid crystal display unit 20 in the extending direction of the first display side 20a. ４ The end of the casing is located on the side of the casing.

[0033] The glass plate 60 is disposed between the opening 10a of the housing 10 and the liquid crystal display unit 20. The glass plate 60 is a transparent glass member formed in a flat plate shape. In this embodiment, the glass plate 60 is formed in a rectangular plate shape with the front-rear direction as the short side and the width direction as the long side. The glass plate 60 is disposed so as to be interposed between the edge of the opening 10a of the housing 10 and the liquid crystal display unit 20. The glass plate 60 functions as a heat conductive member.

[0034] The diffuser plate 70 is a film-like member that diffuses light from the light source. The diffuser plate 70 in this embodiment is formed in a rectangular shape. The diffuser plate 70 is disposed between the opening 10 a of the housing 10 and the glass plate 60.

[0035] The thermally conductive sheet 80 is a sheet-like member having thermal conductivity, such as a thermal sheet. The thermally conductive sheet 80 has a thermal conductivity higher than that of air. In this embodiment, as shown in FIGS. 3 and 5 , the thermally conductive sheet 80 includes a first thermally conductive sheet 81 and a second thermally conductive sheet 82.

[0036] The first thermally conductive sheet 81 and the second thermally conductive sheet 82 are formed in the shape of linearly extending sheets. The first thermally conductive sheet 81 and the second thermally conductive sheet 82 are provided on the edge of the opening 10a in the top wall 11a of the housing 10. In this embodiment, as shown in FIG. 5, the first thermally conductive sheet 81 is provided on the edge of the opening 10a of the housing 10, and the first thermally conductive sheet 81 is provided on the first side wall 11b. １ The second heat conductive sheet 82 is disposed on the edge of the second side wall 11b. ２ That is, the first thermally conductive sheet 81 and the second thermally conductive sheet 82 are spaced apart in the front-rear direction. As described above, the first thermally conductive sheet 81 is disposed on the edge of the opening 10a in the housing 10 by the first groove 11c. １ The second thermally conductive sheet 82 is placed inside the second groove portion 11c formed on the edge of the opening 10a in the housing 10. ２ The first thermally conductive sheet 81 and the second thermally conductive sheet 82 are disposed on either side of the opening 10a of the housing 10 in the front-rear direction.

[0037] The diffusion plate 70 is located between the first thermally conductive sheet 81 and the second thermally conductive sheet 82. The diffusion plate 70 is disposed so as to cover the entire opening 10a, and diffuses light from the light source housed in the housing 10 toward the glass plate 60.

[0038] As shown in Fig. 6, the glass plate 60 is disposed on the diffuser plate 70, the first thermally conductive sheet 81, and the second thermally conductive sheet 82. Between the first thermally conductive sheet 81 and the second thermally conductive sheet 82, the surface of the glass plate 60 on the opening 10a side (the lower surface) is in contact with the diffuser plate 70 from one end to the other in the short side direction of the glass plate 60. Note that between the first thermally conductive sheet 81 and the second thermally conductive sheet 82, the surface of the glass plate 60 on the opening 10a side (the lower surface) may face the diffuser plate 70 with a gap between them from one end to the other in the short side direction of the glass plate 60. The glass plate 60 transmits light diffused by the diffuser plate 70 toward the liquid crystal display unit 20.

[0039] 7 and 8, the liquid crystal display unit 20 is disposed on a glass plate 60. The liquid crystal display unit 20 emits light transmitted through the glass plate 60 as display light L from the display surface.

[0040] In the embodiment, as shown in FIGS. 8 to 10, the flexible printed circuit board unit 40 is pulled out from the first display side 20a of the liquid crystal display unit 20 and is connected to the side wall 11b (first side wall 11b) of the housing 10. １ That is, the wiring portion 42 of the flexible printed circuit board portion 40 is attached to the outer surface of the side wall 11b (first side wall 11b) of the housing 10 with the connection end portion on the liquid crystal display portion 20 side bent. １ ) via an adhesive material. Here, for example, double-sided tape can be used as the adhesive material. In this case, for example, double-sided tape is attached to the back surface of the wiring portion 42, and in this state, the back surface of the wiring portion 42 is attached to the side wall 11b (first side wall 11b １ ) so that the wiring portion 42 can be attached to the outer surface of the side wall 11b.

[0041] In the embodiment, the first side wall 11b is formed at the edge of the opening 10a in the housing 10. １ A space is provided between the edge of the side and the bezel 30, and the wiring part 42 is connected to the first display side 20a of the liquid crystal display part 20 through the space.

[0042] In the image display device 100 according to the embodiment, the wiring section 42 is attached to the side wall 11b of the housing 10, and the display control section 41 arranged on the wiring section 42 is fixed to the housing 10 via the wiring section 42. Note that the flexible printed circuit board section 40 may be provided with a connector or the like for electrically connecting the display control section 41 to an ECU (Electronic Control Unit) or the like of the vehicle 300 (see FIG. 1 ). In this case, the connector is provided when the wiring section 42 is attached to the side wall 11b (first side wall 11b) of the housing 10. １ ), the wiring portion 42 is provided on the surface thereof so as to be positioned on the side wall 11b.

[0043] 9 , a gap SP is provided between the first elastic member 51 and the second elastic member 52, at least between the connection end of the liquid crystal display unit 20 with the flexible printed circuit board unit 40 and the bezel unit 30. By providing the gap SP between the first elastic member 51 and the second elastic member 52, between the end (connection end) of the liquid crystal display unit 20 on the first display side 20a side and the bezel unit 30, it is possible to prevent the elastic member 50 and the like from interfering with the connection portion (wiring unit 42 and the like) between the liquid crystal display unit 20 and the display control unit 41.

[0044] As shown in Figures 9 to 13, the glass plate 60 is in contact with the liquid crystal display unit 20. Contact between the glass plate 60 and the liquid crystal display unit 20 facilitates heat conduction from the liquid crystal display unit 20 to the glass plate 60. It is desirable that the contact area of ​​the glass plate 60 with the liquid crystal display unit 20 be large. For example, the glass plate 60 is in contact with the entire rear surface of the liquid crystal display unit 20. It is preferable that the glass plate 60 cover the entire image display area of ​​the liquid crystal display unit 20. This prevents stress from being applied to localized areas of the liquid crystal display unit 20, thereby preventing whitening. The thickness of the glass plate 60 may be greater than the thickness of the liquid crystal display unit 20. The glass plate 60 in contact with the liquid crystal display unit 20 can increase the thermal capacity of the liquid crystal display unit 20 and absorb heat generated by the liquid crystal display unit 20.

[0045] The glass plate 60 in this embodiment is sapphire glass, which has a thermal conductivity at least higher than that of air. Sapphire glass is formed, for example, by artificially growing high-purity alumina (aluminum oxide) into large crystals. The sapphire glass is bonded to the liquid crystal display unit 20 by optical bonding, such as OCA (Optical Clear Adhesive) or OCR (Optical Clear Resin).

[0046] Furthermore, the edge of the lower surface of the glass plate 60 is in contact with the upper surface of the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82). At least the lower surface of the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) is in contact with the housing 10. With this configuration, heat generated in the liquid crystal display unit 20 is transferred to the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) via the glass plate 60. The thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) receives heat from the liquid crystal display unit 20 via the glass plate 60 and transfers it to the housing 10. The housing 10 dissipates the heat received from the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) to the outside.

[0047] 12 and 13 , the image display device 100 of the embodiment uses the bezel 30 to press the liquid crystal display unit 20 against the housing 10 via the elastic members 50 at both ends of the liquid crystal display unit 20, thereby preventing rattling of the liquid crystal display unit 20. The bezel 30 also prevents the liquid crystal display unit 20 from lifting up in the vertical direction. Furthermore, by pressing the liquid crystal display unit 20, glass plate 60, and thermally conductive sheet 80 against the housing 10 via the elastic members 50, the bezel 30 maintains good contact between these components and improves thermal conductivity.

[0048] 14 and 15, the first groove 11c of the housing 10 １ The first groove 11c is formed as a groove having a size and shape (here, the shape when viewed from above is rectangular) corresponding to the first thermal conductive sheet 81. １ The depth of the second groove 11c of the housing 10 is slightly shallower than the thickness of the first thermally conductive sheet 81. ２ The second groove portion 11c is formed to a size and shape (here, the shape when viewed from above is rectangular) corresponding to the second thermal conductive sheet 82. ２ The depth of the recess 11c is slightly shallower than the thickness of the second thermally conductive sheet 82. Therefore, the surface (top surface) of the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) that is in contact with the glass plate 60 is located closer to the glass plate 60 than the surface surrounding the groove 11c in the housing 10. With this configuration, the glass plate 60 is held in a state where it is slightly raised relative to the edge of the opening 10a in the housing 10. With this configuration, it is possible to prevent the glass plate 60 from coming into direct contact with the housing 10, and to prevent the glass plate 60 from being scratched by the housing 10 made of hard metal, for example.

[0049] In this embodiment, the first thermally conductive sheet 81 and the second thermally conductive sheet 82 extend along the width direction. The first thermally conductive sheet 81 is disposed so as to contact one end of the glass plate 60 along the long side, and the second thermally conductive sheet 82 is disposed so as to contact one end of the glass plate 60 along the long side. The first thermally conductive sheet 81 contacts one end of the glass plate 60 along the long side from one end to the other in the width direction, and the second thermally conductive sheet 82 contacts one end of the glass plate 60 along the long side from one end to the other in the width direction. The upper surfaces of the first thermally conductive sheet 81 and the second thermally conductive sheet 82 each contact the lower surface of the glass plate 60 entirely. In this embodiment, a thermistor (not shown) mounted on an aluminum substrate is disposed below the first thermally conductive sheet 81. The thermistor is a component for measuring the temperature of the liquid crystal display unit 20 through the glass plate 60. In the embodiment, a recess is partially formed on the edge of the opening 10a in the housing 10 to accommodate a thermistor (not shown) mounted on an aluminum substrate, and the first thermally conductive sheet 81 is arranged to cover the thermistor accommodated in the recess of the housing 10. In the embodiment, the thermally conductive sheet 80 (the first thermally conductive sheet 81 and the second thermally conductive sheet 82) is provided so as to contact only both ends along the long sides of the glass plate 60. In other words, the glass plate 60 does not overlap with the thermally conductive sheet 80 (the first thermally conductive sheet 81 and the second thermally conductive sheet 82) in the up-down direction, except for both ends along the long sides.

[0050] The diffusion plate 70 is provided so as not to overlap the first thermally conductive sheet 81 and the second thermally conductive sheet 82 in the up-down direction. That is, the diffusion plate 70 forms a thermally conductive sheet-free area where the thermally conductive sheet 80 is not laminated. The surface of the glass plate 60 on the opening 10a side of the housing 10 (the lower surface of the glass plate 60) faces the diffusion plate 70 from one end to the other end in the short side direction without the thermally conductive sheet 80 (the first thermally conductive sheet 81 and the second thermally conductive sheet 82) interposed therebetween.

[0051] In this embodiment, the diffuser plate 70 and the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) are attached to the housing 10 so that their respective upper surfaces are flush with each other, and the upper surfaces of the diffuser plate 70 and the thermally conductive sheet 80 (first thermally conductive sheet 81 and second thermally conductive sheet 82) are in contact with the glass plate 60. This configuration prevents the glass plate 60 from rattling, and the diffuser plate 70 and the thermally conductive sheet 80 also function as buffers between the hard metal housing 10 and the glass plate 60. Furthermore, the first thermally conductive sheet 81 is sandwiched between the glass plate 60 and the thermistor without the diffuser plate 70 or the like interposed therebetween. This configuration allows the thermistor to properly measure the temperature of the glass plate 60.

[0052] As described above, the image display device 100 according to the embodiment includes a metal housing 10 having an opening 10a formed in an upper wall 11a and housing a light source that irradiates light toward the opening 10a, a liquid crystal display unit 20 that is positioned to cover the opening 10a and emits light from the light source as display light L for an image, a glass plate 60 that is positioned between the opening 10a of the housing 10 and the liquid crystal display unit 20 and is in contact with the liquid crystal display unit 20, allowing the light from the light source to pass through to the liquid crystal display unit 20, and a heat conduction sheet 80 that is positioned between the edge of the opening 10a in the housing 10 and the edge of the glass plate 60, and receives heat from the liquid crystal display unit 20 via the glass plate 60 and transfers it to the housing 10.

[0053] The image display device 100 according to the embodiment can improve the heat dissipation of the image display device 100 by transferring heat generated in the liquid crystal display unit 20 to the metal housing 10 via the glass plate 60 and the thermally conductive sheet 80. Furthermore, by interposing the thermally conductive sheet 80 between the glass plate 60 and the metal housing 10, it is possible to reduce the impact that the glass plate 60 receives from the housing 10 when the image display device 100 vibrates. That is, in the image display device 100 according to the embodiment, the thermally conductive sheet 80 also functions as a buffer between the glass plate 60 and the housing 10. It is also possible to suppress noise and the like that may be generated by contact between the glass plate 60 and the housing 10. With this configuration, the image display device 100 according to the embodiment can improve heat dissipation and vibration resistance.

[0054] Furthermore, in the image display device 100 according to the embodiment, the glass plate 60 is formed in the shape of a rectangular plate, and the thermal conduction sheet 80 includes a first thermal conduction sheet 81 in contact with one end along the long side of the glass plate 60 and a second thermal conduction sheet 82 in contact with the other end along the long side of the glass plate 60, and the first thermal conduction sheet 81 and the second thermal conduction sheet 82 are spaced apart in the short side direction along the short side of the glass plate 60.

[0055] In the image display device 100 according to the embodiment, the first thermally conductive sheet 81 and the second thermally conductive sheet 82, which are spaced apart in the short-side direction of the glass plate 60, are in contact with the edges of the glass plate 60 along the long side, respectively, thereby ensuring thermal conductivity and improving the manufacturing efficiency of the thermally conductive sheet 80. Furthermore, the workability of the installation work of the thermally conductive sheet 80 can also be improved. For example, when manufacturing a frame-shaped thermally conductive sheet, the shape of the thermally conductive sheet must be adapted to the shape of the edge of the housing 10, which makes the shape of the thermally conductive sheet more complex than the shape of the thermally conductive sheet 80 (the first thermally conductive sheet 81 and the second thermally conductive sheet 82). Therefore, compared to the thermally conductive sheet 80 (the first thermally conductive sheet 81 and the second thermally conductive sheet 82), it may be difficult to maintain a high yield rate with the frame-shaped thermally conductive sheet. Furthermore, if the thermal conduction sheet is frame-shaped, it is necessary to attach the thermal conduction sheet so that it surrounds the opening 10a of the housing 10, which may impair the workability of the installation work compared to the above-mentioned thermal conduction sheet 80 (first thermal conduction sheet 81 and second thermal conduction sheet 82).

[0056] In addition, the image display device 100 according to the embodiment further includes a diffuser plate 70 provided between the first thermal conduction sheet 81 and the second thermal conduction sheet 82, which diffuses light from the light source toward the glass plate 60, and between the first thermal conduction sheet 81 and the second thermal conduction sheet 82, the surface of the glass plate 60 on the opening 10a side faces the diffuser plate 70 from one end to the other end in the short side direction.

[0057] In the image display device 100 according to the embodiment, the first thermally conductive sheet 81 and the second thermally conductive sheet 82, which are spaced apart in the short-side direction of the glass plate 60, are brought into contact with the ends along the long side of the glass plate 60, respectively, thereby ensuring thermal conductivity and improving the manufacturing efficiency of the thermally conductive sheet 80. The workability of the installation work of the thermally conductive sheet 80 can also be improved. Furthermore, in the image display device 100 according to the embodiment, by providing a diffusion plate 70 between the first thermally conductive sheet 81 and the second thermally conductive sheet 82, light from the light source can be made uniform and incident on the liquid crystal display unit 20.

[0058] Furthermore, in the image display device 100 according to the embodiment, the heat conduction sheet 80 is placed inside a groove 11c formed on the edge of the opening 10a in the housing 10, and the surface of the heat conduction sheet 80 in contact with the glass plate 60 is located closer to the glass plate 60 than the surface surrounding the groove 11c in the housing 10.

[0059] In the image display device 100 according to the embodiment, by providing the groove portion 11c in the housing 10, it is possible to improve the workability of attaching the thermally conductive sheet 80 to the housing 10. It is also possible to suppress misalignment of the thermally conductive sheet 80 with respect to the housing 10.

[0060] In the above embodiment, the windshield is used as the display member 301 of the vehicle 300, but the present invention is not limited to this. The display member 301 may be, for example, a combiner.

[0061] In the above embodiment, the vehicle display device 200 has been described as having two reflective members (the first reflective member 202 and the second reflective member 203), but this is not limiting. For example, the vehicle display device 200 may have only one reflective member. Furthermore, the vehicle display device 200 may directly emit the display light L to the display member 301.

[0062] Although the above embodiment has been described using an example in which double-sided tape is used as the adhesive material, the present invention is not limited to this. For example, the adhesive material may be an adhesive agent or the like.

[0063] Furthermore, in the above embodiment, an example has been described in which the elastic member 50 includes the first elastic member 51 and the second elastic member 52, but this is not limiting. The elastic member 50 may be provided on an end of the liquid crystal display unit 20 other than the end on the first display side 20a side. For example, the elastic member 50 may be a single U-shaped elastic member arranged on an end of the liquid crystal display unit 20 other than the end on the first display side 20a side. In this case, an elastic member can also be arranged above the second thermally conductive sheet 82, thereby enabling stronger contact between the liquid crystal display unit 20, the glass plate 60, and the second thermally conductive sheet 82.

[0064] In addition, in the above embodiment, an example has been described in which the glass plate 60 is placed in contact with the liquid crystal display unit 20 using optical bonding such as OCA or OCR, but this is not limited to this, and the glass plate 60 may be placed in contact with the liquid crystal display unit 20 using other methods.

[0065] The contents disclosed in the above embodiments can be implemented in appropriate combinations.

[0066] 10: Housing 20: Liquid crystal display unit 30: Bezel unit 40: Flexible printed circuit board unit 41: Display control unit 42: Wiring unit 50: Elastic member 51: First elastic member 52: Second elastic member 60: Glass plate 70: Diffusion plate 80: Heat conduction sheet 81: First heat conduction sheet 82: Second heat conduction sheet 100: Image display device 200: Vehicle display device 300: Vehicle

Claims

1. An image display device comprising: a metal housing having an opening formed in an upper wall and accommodating a light source that irradiates light toward said opening; a liquid crystal display unit that is positioned to cover said opening and emits light from said light source as light for displaying an image; a glass plate that is positioned between said opening in said housing and said liquid crystal display unit and is in contact with said liquid crystal display unit, and that transmits light from the light source toward said liquid crystal display unit; and a heat conduction sheet that is positioned between the edge of said opening in said housing and the edge of said glass plate, and that receives heat from the liquid crystal display unit through said glass plate and transfers it to said housing.

2. The image display device according to claim 1, wherein the glass plate is formed in a rectangular plate shape, the thermally conductive sheet includes a first thermally conductive sheet in contact with one end of the glass plate along the long side, and a second thermally conductive sheet in contact with the other end of the glass plate along the long side, and the first thermally conductive sheet and the second thermally conductive sheet are spaced apart in the short side direction along the short side of the glass plate.

3. The image display device according to claim 2, further comprising a diffusion plate provided between the first thermal conduction sheet and the second thermal conduction sheet to diffuse light from the light source toward the glass plate, and between the first thermal conduction sheet and the second thermal conduction sheet, the surface of the glass plate on the opening side faces the diffusion plate from one end to the other end in the short side direction.

4. An image display device as claimed in any one of claims 1 to 3, wherein the heat conduction sheet is placed inside a groove formed in the edge of the housing, and the surface of the heat conduction sheet in contact with the glass plate is located closer to the glass plate than the surface of the housing surrounding the groove.

Images