Image projection device

Abstract

In an image projection device (10) according to the present invention, a reflection mirror (40) is provided with an effective reflection region (42) that performs reflection control on light emitted from an image generation unit (20), and an outer peripheral edge region (44) that surrounds the entire periphery of the effective reflection region (42). The outer peripheral edge region (44) is formed thicker than the effective reflection region (42). Required rigidity is thus secured without much increase in the weight of the reflection mirror (40). Consequently, the deformation of the reflection mirror (40) is suppressed, and the optical function of the reflection mirror (40) is maintained. In addition, the reflection mirror (40) is configured to be supported by a first housing (52) or the like in the outer peripheral edge region (44). Consequently, the effective reflection region (42) is prevented from being deformed.

Description

Image irradiation device

[0001] The present disclosure relates to an image projection device configured to project a display image generated by an image generation unit onto an image display unit as a virtual image.

[0002] An in-vehicle image projection device is known, which is configured to project a virtual image onto an image display unit, such as a windshield or a light-transmitting plate, disposed inside the vehicle cabin when the image projection device is disposed inside the vehicle cabin.

[0003] For example, Patent Document 1 discloses an image projection device that includes an image generation unit that generates a display image that serves as the basis for a virtual image, a reflecting mirror that reflects light emitted from the image generation unit toward an image display unit, and a reflecting mirror support member that supports the reflecting mirror.

[0004] The image projection device described in Patent Document 1 includes, as reflecting mirrors, first and second reflecting mirrors that sequentially reflect light emitted from the image generating unit toward the image display section.

[0005] Patent Document 2 discloses an image generation unit for generating a display image that serves as the basis for a virtual image in an image projection device. The image generation unit includes a liquid crystal panel and an optical unit that irradiates the liquid crystal panel with a backlight.

[0006] In the image projection device described in Patent Document 2, a heat transfer panel is disposed between the liquid crystal panel and a heat sink that supports an optical unit.

[0007] Japanese Patent Publication No. 2023-76351 Japanese Patent Publication No. 2020-3732

[0008] In the image projection device described in Patent Document 1, the reflecting mirror (specifically, the second reflecting mirror) has a relatively large reflecting surface. If the outer shape of the reflecting surface becomes even larger, the reflecting mirror becomes more susceptible to deformation, making it difficult to ensure the rigidity required to maintain the optical function of the reflecting mirror.

[0009] One way to address this issue is to increase the rigidity of the reflector by increasing its thickness, but this would increase the weight of the reflector and the time required to mold it, which would increase costs.

[0010] It is also possible to reinforce the reflector by assembling a frame member or the like, without increasing the thickness of the reflector itself, but this would result in an increase in the number of parts, which would increase costs and weight.

[0011] Furthermore, in order to project a bright virtual image onto the image display section of the image projection device, the image generation unit needs to be equipped with a high-output optical unit, but in this case, the liquid crystal panel is prone to overheating.

[0012] In response to this problem, it is conceivable to place a heat transfer panel between the liquid crystal panel and the heat sink, as described in Patent Document 2. In this case, the heat generated by the liquid crystal panel can be dissipated to the heat sink via the heat transfer panel, thereby making it possible to prevent the liquid crystal panel from overheating.

[0013] However, in this case, a new heat transfer panel is required, which increases the cost of the image projection device.

[0014] These problems may also occur in image projection devices other than those mounted on vehicles.

[0015] The present disclosure relates to an image projection device configured to project a display image generated by an image generation unit onto an image display unit as a virtual image. One of the objects of the present disclosure is to provide an image projection device that can realize a lightweight and inexpensive configuration while ensuring the optical function of the reflecting mirror that reflects light emitted from the image generation unit toward the image display unit, even if the reflecting mirror is large.

[0016] Another object of the present disclosure is to provide an image projection device that can generate a bright image for display while suppressing the cost of the image projection device.

[0017] The present disclosure aims to achieve one of the above-mentioned objects by improving the configuration of the reflecting mirror.

[0018] The image projection device according to the present disclosure is an image projection device configured to project a display image generated by an image generation unit as a virtual image on an image display unit, and includes a reflector that reflects light emitted from the image generation unit toward the image display unit, and a reflector support member that supports the reflector, wherein the reflector includes an effective reflection area that controls the reflection of the light emitted from the image generation unit, and an outer peripheral edge area that surrounds the effective reflection area all around, the outer peripheral edge area being thicker than the effective reflection area, and the reflector is supported by the reflector support member at the outer peripheral edge area.

[0019] The image projection device is not particularly limited in its specific use as long as it is configured to project a virtual image on the image display unit. The image projection device may be, for example, an in-vehicle head-up display.

[0020] The image display unit is not particularly limited in its specific configuration as long as it is configured to display a virtual image. The image display unit may be, for example, a translucent plate disposed on the front window of the vehicle or on the inside of the vehicle compartment.

[0021] In the reflecting mirror, the specific boundary position between the effective reflection area and the outer peripheral area is not particularly limited.

[0022] As long as the outer peripheral region of the reflecting mirror is thicker than the effective reflecting region, the specific thickness of each region is not particularly limited.

[0023] As long as the reflector is supported by the reflector support member in the outer peripheral region, the specific support structure is not particularly limited.

[0024] Furthermore, the present disclosure aims to achieve the other object described above by devising a configuration for the image generation unit.

[0025] The image projection device according to the present disclosure is an image projection device configured to project a display image generated by an image generation unit onto an image display unit as a virtual image, wherein the image generation unit includes a liquid crystal panel, an optical unit that irradiates the liquid crystal panel with backlight, a panel support member that supports the liquid crystal panel, and a mask member that covers the outer peripheral edge region of the liquid crystal panel, the optical unit being mounted on a heat sink fixed to the panel support member, and the mask member being made of a material having a higher thermal conductivity than the liquid crystal panel, and being fixed to the panel support member while being positioned so as to be in contact with the heat sink.

[0026] The mask member is disposed so as to cover the peripheral edge region of the liquid crystal panel. The mask member has an opening, the shape of which is not particularly limited.

[0027] The mask member is not particularly limited to a specific material as long as it is made of a material with a higher thermal conductivity than the liquid crystal panel, and the specific manner of contact between the mask member and the heat sink is not particularly limited.

[0028] The image projection device according to the present disclosure is configured to project a display image generated by an image generation unit as a virtual image on an image display section, and reflects light emitted from the image generation unit toward the image display section using a reflecting mirror. The reflecting mirror has an effective reflection area that controls the reflection of the light emitted from the image generation unit, and an outer peripheral area that surrounds the effective reflection area over its entire circumference. The reflecting mirror is formed so that the outer peripheral area is thicker than the effective reflection area, and is supported by a reflecting mirror support member at the outer peripheral area. Therefore, the image projection device according to the present disclosure can achieve the following effects.

[0029] Because the outer peripheral region is thicker than the effective reflection region, it is possible to ensure the necessary rigidity without significantly increasing the weight of the reflector, thereby suppressing deformation of the reflector and maintaining the optical function of the reflector.

[0030] The reflector is supported at its outer peripheral edge by the reflector support member, which prevents deformation in the effective reflection area that could adversely affect the function of the reflector.

[0031] In this way, the image projection device of the present disclosure is configured to project the display image generated by the image generation unit onto the image display unit as a virtual image. According to the present disclosure, in such an image projection device, even if the reflecting mirror that reflects the light emitted from the image generation unit toward the image display unit is increased in size, it is possible to realize a lightweight and inexpensive configuration while ensuring the optical function of the reflecting mirror.

[0032] The image projection device of the present disclosure may further be configured to project a first virtual image in a lower region of the image display unit and a second virtual image in an upper region thereof. In this case, the image projection device may include, as effective reflection areas of the reflecting mirror, a first reflection region that reflects a display image that is the source of the first virtual image and a second reflection region that reflects a display image that is the source of the second virtual image. Furthermore, the first reflection region is an area above the second reflection region that is narrower in width than the second reflection region, and the reflecting mirror is supported by a reflecting mirror support member at both left and right portions of the first reflection region in the outer peripheral region. In this case, the image projection device of the present disclosure can achieve the following effects.

[0033] When the effective reflection area is configured such that the first reflection area is located above the second reflection area and has a narrower left-right width than the second reflection area, it becomes easy to secure space for arranging a structure for supporting the reflector on both sides of the first reflection area in the outer peripheral area. Therefore, by effectively utilizing this space, it becomes possible to secure sufficient rigidity for the reflector supported by the reflector support member.

[0034] The reflector may be configured such that the effective reflection area is formed with a constant thickness, and an annular rib that surrounds the entire effective reflection area is formed in the outer peripheral edge area. In this case, it becomes easier to maintain the optical function required as a reflector in the effective reflection area and to ensure the rigidity required as a reflector in the outer peripheral edge area.

[0035] When the reflecting mirror is configured as a concave mirror having a rectangular outer shape, it becomes difficult to maintain the surface precision of the effective reflection area, so it is even more effective to adopt the configuration of the present disclosure.

[0036] When the reflector is supported rotatably around an axis extending in the left-right direction relative to the reflector support member, it becomes difficult to maintain the surface precision of the effective reflection area, so adopting the configuration of the present disclosure is even more effective.

[0037] The image projection device according to the present disclosure includes an image generation unit that generates a display image that is the basis for a virtual image projected on an image display unit. Specifically, the image projection device includes, as the image generation unit, a liquid crystal panel, an optical unit that irradiates the liquid crystal panel with a backlight, a panel support member that supports the liquid crystal panel, and a mask member that covers the outer peripheral area of ​​the liquid crystal panel. Therefore, the image projection device according to the present disclosure can achieve the following effects.

[0038] The mask member is disposed in the image projection device, so that the usable area of ​​the liquid crystal panel can be defined. Furthermore, even if sunlight enters the internal space of the image projection device, the light-blocking function of the mask member makes it possible to suppress the temperature rise of the liquid crystal panel to a certain extent.

[0039] Furthermore, in the image projection device according to the present disclosure, a heat sink carrying an optical unit is fixed to the panel support member. Furthermore, the mask member is made of a material having a higher thermal conductivity than the liquid crystal panel, and is fixed to the panel support member while being disposed so as to be in contact with the heat sink. Therefore, the image projection device according to the present disclosure can achieve the following effects.

[0040] Even if the LCD panel heats up due to backlight irradiation from the optical unit or sunlight, the heat can be dissipated to the heat sink via the masking material, which has a higher thermal conductivity than the LCD panel. This effectively prevents the LCD panel from overheating. Furthermore, the output of the optical unit can be increased while maintaining the functionality of the LCD panel.

[0041] Furthermore, the above-mentioned effects can be achieved by using a mask member that defines the usable area of ​​the liquid crystal panel instead of using a dedicated heat transfer panel. Therefore, according to the present disclosure, it is possible to generate a bright display image while suppressing the cost of the image projection device.

[0042] Thus, according to the present disclosure, in an image projection device configured to project a display image generated by an image generation unit as a virtual image on an image display unit, it is possible to generate a bright display image while reducing the cost of the image projection device.

[0043] Furthermore, in the image projection device according to the present disclosure, when the mask member is fixed to the panel support member by caulking, the following advantageous effects can be obtained.

[0044] According to the present disclosure, the number of parts of the image projection device can be reduced compared to fixing by screw fastening or the like.

[0045] Furthermore, compared to fixation using lance engagement, etc., excessive load is less likely to be placed on the liquid crystal panel, and gaps that could cause vibration of the mask member between the panel support member and the mask member are prevented from accidentally occurring.

[0046] In the image projection device according to the present disclosure, the panel support member is made of a resin material, and when the mask member is fixed to the panel support member by thermal crimping, the fixing can be performed more easily than by cold crimping.

[0047] In the image projection device according to the present disclosure, when openings are formed in two places in the mask member, the following effects can be obtained.

[0048] The mask member is configured with a beam-like portion formed between the two openings, which increases the rigidity of the mask member and allows the heat generated by the liquid crystal panel to be conducted to the heat sink more efficiently.

[0049] In addition, two usable areas are set on the liquid crystal panel, which allows two types of virtual images to be displayed on the image display unit in two locations.

[0050] Furthermore, if the image projection device is equipped with a concave mirror that reflects the light emitted from the image generation unit toward the image display unit, sunlight that enters the internal space of the image projection device is reflected by the concave mirror and tends to be concentrated at the edge of the liquid crystal panel. Therefore, it is particularly effective to suppress the temperature rise of the liquid crystal panel by using the light-shielding function of a mask member arranged to cover the outer peripheral area of ​​the liquid crystal panel.

[0051] FIG. 1 is a side cross-sectional view showing an image projection device according to a first embodiment of the present disclosure mounted on a vehicle. FIG. 2A is a view taken in the direction of an arrow II in FIG. 1. FIG. 2B is a view taken in the direction of an arrow II in FIG. 1. FIG. 3 is a detailed view of part III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a view taken in the direction of an arrow V in FIG. 4 showing in detail a reflecting mirror of the image projection device. FIG. 6A is a view taken in the direction of an arrow II in FIG. 1 of an image projection device according to a first modified example of the first embodiment. FIG. 6B is a view taken in the direction of an arrow II in FIG. 1 of an image projection device according to a first modified example of the first embodiment. FIG. 7 is a view taken in the direction of an arrow V in FIG. 4 of a reflecting mirror of an image projection device according to a second modified example of the first embodiment. FIG. 8 is a side cross-sectional view of an image projection device according to a third modified example of the first embodiment. FIG. 9 is a side cross-sectional view showing an image projection device according to a second embodiment of the present disclosure mounted on a vehicle. FIG. 10 is a view taken in the direction of an arrow X in FIG. 9. FIG. 11 is a detailed view of part XI in FIG. 9. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11. Fig. 13 is a perspective view showing an image generation unit of an image projection device together with a heat sink. Fig. 14 is an exploded perspective view showing the image generation unit. Fig. 15 is a perspective view showing an image generation unit of an image projection device according to a modified example of the second embodiment together with a heat sink.

[0052] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[0053] First Embodiment Fig. 1 is a side cross-sectional view showing an image projection device 10 according to a first embodiment in a state where it is mounted on a vehicle 100. Figs. 2A and 2B are views taken in the direction of the arrow II in Fig. 1 .

[0054] 1, 2A, and 2B, the direction indicated by X is the "forward" direction of the image projection device 10 (also "forward" as a vehicle), the direction indicated by Y is the "leftward" direction perpendicular to the "forward" direction, and the direction indicated by Z is the "upward" direction. This is the same in figures other than FIGS. 1, 2A, and 2B.

[0055] 1, 2A, and 2B, the image projection device 10 according to this embodiment is an in-vehicle head-up display. The image projection device 10 is configured to project two types of virtual images PIC-A and PIC-B onto an image display unit 106 provided on the inner surface of a windshield 102 when placed in the cabin of a vehicle 100.

[0056] An optical path R shown in FIG. 1 is an optical path taken by the driver 2 when the driver 2 visually recognizes the virtual images PIC-A and PIC-B projected on the image display unit 106 by the image projection device 10.

[0057] The image display unit 106 is positioned below the windshield 102 and in front of the steering wheel 104, and has a horizontally long rectangular area. This allows the driver 2 of the vehicle 100 to easily visually recognize the virtual images PIC-A and PIC-B projected on the image display unit 106.

[0058] 2A and 2B, the image display unit 106 includes a lower region 106A and an upper region 106B. The lower region 106A and the upper region 106B are both horizontally elongated rectangular regions. The upper edge of the lower region 106A partially overlaps the lower edge of the upper region 106B. The upper region 106B is slightly horizontally elongated compared to the lower region 106A.

[0059] With regard to the two types of virtual images PIC-A and PIC-B, the virtual image PIC-A is displayed in a lower region 106A of the image display unit 106, and the virtual image PIC-B is displayed in an upper region 106B of the image display unit 106.

[0060] Specifically, when the vehicle speed is in the low-to-medium speed range (for example, a speed range of 80 km / h or less), the virtual image PIC-A is displayed in the lower region 106A as shown in Fig. 2A. On the other hand, when the vehicle speed exceeds the low-to-medium speed range and enters a high-speed range, the virtual image PIC-B is displayed in the upper region 106B as shown in Fig. 2B. This ensures that when the driver 2 moves his / her viewpoint from the field of view ahead of the vehicle to the virtual images PIC-A and PIC-B, the amount of viewpoint movement by the driver 2 is kept as small as possible regardless of the vehicle speed.

[0061] 2A and 2B show a state in which a plurality of images are displayed as specific examples of virtual images PIC-A and PIC-B.

[0062] 2A, the virtual image PIC-A includes an image of an arrow bent to the left, an image showing the distance (40 m) ahead to the left turn point, an image showing the gear shift position (D), an image showing a mark with the speed limit (60 km / h) surrounded by a circle, and an image showing the actual vehicle speed (50 km / h). These images are arranged from right to left.

[0063] 2B, the virtual image PIC-B includes an image of an arrow bent to the left, an image showing the distance (80 m) ahead to the left turn point, an image showing the gear shift position (D), an image showing a mark with the speed limit (120 km / h) surrounded by a circle, and an image showing the actual vehicle speed (100 km / h). These images are arranged from right to left.

[0064] The image projection device 10 is disposed in front of the steering wheel 104 and in the vicinity of the lower part of the windshield 102 .

[0065] As shown in FIG. 1 , the image projection device 10 includes an image generation unit 20, a reflecting mirror 40, a housing 50, a light-transmitting cover 60, and a control unit 80. The image generation unit 20 generates a display image that is the basis for virtual images PIC-A and PIC-B. The reflecting mirror 40 reflects light emitted from the image generation unit 20 toward an image display section 106 on a front window 102. The housing 50 accommodates the image generation unit 20 and the reflecting mirror 40. The light-transmitting cover 60 is attached to the housing 50. The control unit 80 controls the image generation unit 20.

[0066] Fig. 3 is a detailed view of part III in Fig. 1. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3.

[0067] 3, the housing 50 includes a first housing 52 and a second housing 54. The second housing 54 is assembled to the first housing 52, which is formed to open upward. Specifically, the second housing 54 has an outer peripheral flange portion 54b, and is assembled to the first housing 52 with the outer peripheral flange portion 54b abutting against the upper end opening of the peripheral wall portion 52a of the first housing 52.

[0068] The first and second housings 52, 54 are both made of opaque resin molding. The second housing 54 has an upper opening 54a that allows reflected light from the reflecting mirror 40 to pass through toward the image display unit 106.

[0069] The light-transmitting cover 60 is made of a colorless, transparent resin panel. The light-transmitting cover 60 is arranged so as to cover the upper opening 54a of the second housing 54, in a state where it is curved downward and tilted slightly upward toward the rear of the device. The light-transmitting cover 60 allows the light emitted from the image generating unit 20, reflected by the reflecting mirror 40, to enter the image display unit 106, while ensuring that the internal space 12 of the housing 50 is dust-proof.

[0070] The second housing 54 is formed with a light-shielding piece 54c that extends diagonally downward and forward from the rear edge of the upper opening 54a toward the internal space 12. The light-shielding piece 54c prevents sunlight that has entered the internal space 12 through the front window 102 and the translucent cover 60 from reaching the image generation unit 20 as direct light.

[0071] The image generating unit 20 is arranged in the rear region of the interior space 12. The reflecting mirror 40 is arranged in the front region of the interior space 12.

[0072] 3 and 4, the reflecting mirror 40 is configured as a concave mirror. The reflecting surface 40a of the reflecting mirror 40 has a horizontally elongated rectangular outer shape when viewed from the front of the device. The image generating unit 20 is disposed relative to the reflecting mirror 40 so as to be positioned at the center of the reflecting mirror 40 in the left-right direction. The specific configuration of the reflecting mirror 40 will be described later.

[0073] The image generating unit 20 includes a liquid crystal panel 22, a plurality of light-emitting elements 24A and 24B, a substrate 26, a lens member 28, a lens holder 30, and a heat sink 32. The plurality of light-emitting elements 24A and 24B provide backlight illumination to the liquid crystal panel 22 from the rear side of the liquid crystal panel 22 (i.e., the rear side of the device). The substrate 26 mounts the plurality of light-emitting elements 24A and 24B. The lens member 28 deflects and controls the light emitted from the plurality of light-emitting elements 24A and 24B. The lens holder 30 supports the lens member 28. The heat sink 32 supports the lens holder 30.

[0074] The liquid crystal panel 22 has a horizontally elongated rectangular shape and is supported by a lens holder 30 at its outer periphery, in a state where the liquid crystal panel 22 is arranged along a vertical plane perpendicular to the front-rear direction of the device.

[0075] The plurality of light-emitting elements 24A, 24B are all white light-emitting diodes and are arranged in a vertical and horizontal lattice pattern. Specifically, the plurality of light-emitting elements 24A, 24B are arranged in four locations at equal intervals in the vertical direction and in six locations at equal intervals in the horizontal direction, for a total of 24 locations.

[0076] When the vehicle speed is in the low to medium speed range, the plurality of light emitting elements 24A located in the upper half are lit, and when the vehicle speed is in the high speed range, the plurality of light emitting elements 24B located in the lower half are lit.

[0077] The substrate 26 is supported on a heat sink 32 at the rear surface of the substrate 26, with the light-emitting surfaces of the multiple light-emitting elements 24A, 24B arranged along a vertical plane perpendicular to the front-to-rear direction of the device so that they face the front of the device.

[0078] The lens member 28 has a horizontally elongated rectangular plate-like portion disposed along a vertical plane perpendicular to the front-rear direction of the device, and multiple convex lens portions 28A, 28B are formed on the front surface of the plate-like portion. The multiple convex lens portions 28A, 28B are formed in 24 locations so as to be positioned in front of the multiple light-emitting elements 24A, 24B. As a result, the multiple convex lens portions 28A, 28B are configured to deflect the light emitted from each of the multiple light-emitting elements 24A, 24B toward the front of the device. The lens member 28 is supported by a lens holder 30 at the outer peripheral edge of the plate-like portion of the lens member 28. The lens holder 30 is supported by a heat sink 32 at the rear end surface of the lens holder 30.

[0079] The heat sink 32 is made of a metal member such as aluminum. The heat sink 32 includes a main body 32A and multiple heat dissipation fins 32B. The main body 32A extends flat along a vertical plane perpendicular to the front-to-rear direction of the device. The multiple heat dissipation fins 32B extend from the main body 32A toward the rear of the device at intervals in the left-to-right direction.

[0080] The image generating unit 20 deflects light emitted from the plurality of light emitting elements 24A and 24B using a lens member 28, and then causes the light to be incident on the liquid crystal panel 22. In this way, the image generating unit 20 is configured to generate a display image (i.e., an image that serves as the basis for the virtual images PIC-A and PIC-B) on the liquid crystal panel 22.

[0081] The reflecting mirror 40 is supported by the first housing 52 so as to be rotatable about an axis Ax extending in the left-right direction.

[0082] Specifically, an actuator 70 that rotates the reflecting mirror 40 about the axis Ax is fixed to the first housing 52. The actuator 70 is fixed by fastening screws 72 to the bottom wall of the first housing 52 at tab-shaped mounting portions 70b formed at two locations on the actuator 70.

[0083] The reflecting mirror 40 includes vertical flange portions 46. The vertical flange portions 46 are formed so as to protrude rearward from both left and right sides of the rear surface (i.e., the surface facing the front of the device) of the reflecting surface 40a of the reflecting mirror 40. A pair of left and right shaft portions 48L, 48R are formed on the pair of left and right vertical flange portions 46, protruding outward in the left-right direction along the axis Ax. The left-side shaft portion 48L (the right-side when viewed from the front of the device) is placed on a mounting portion 52b formed on the inner surface of the peripheral wall portion 52a of the first housing 52. The right-side shaft portion 48R is directly connected to the output shaft 70a of the actuator 70.

[0084] The mounting portion 52b has a mounting surface that is substantially U-shaped. The second housing 54 is formed with a contact portion (not shown) that contacts the shaft portion 48L mounted on the mounting portion 52b from above to position the reflecting mirror 40.

[0085] The control unit 80 shown in FIG. 1 is configured to control the image generating unit 20 in accordance with the vehicle driving conditions.

[0086] More specifically, the control unit 80 is configured to control the display content of the liquid crystal panel 22 in the image generation unit 20 and the turning on and off of the plurality of light-emitting elements 24A, 24B based on information related to vehicle travel, such as vehicle speed, gear position, video from an on-board camera, and vehicle position, as well as external information, such as map data, weather, and time. When the vehicle speed is in the low-to-medium speed range, the control unit 80 turns on the plurality of light-emitting elements 24A to form a virtual image PIC-A, and when the vehicle speed is in the high-speed range, the control unit 80 turns on the plurality of light-emitting elements 24B to form a virtual image PIC-B.

[0087] FIG. 5 is a view taken in the direction of arrow V in FIG. 4, showing the reflecting mirror 40 in detail.

[0088] As also shown in FIG. 5, the reflecting mirror 40 has an effective reflection area 42 that controls the reflection of light emitted from the image generating unit 20, and an outer peripheral edge area 44 that surrounds the effective reflection area 42 over the entire periphery.

[0089] The reflecting mirror 40 is formed so that the outer peripheral edge region 44 is thicker than the effective reflecting region 42. The reflecting mirror 40 is supported at the outer peripheral edge region 44 by a first housing 52 serving as a reflecting mirror support member and a drive unit.

[0090] The effective reflection area 42 includes a first reflection area 42 A and a second reflection area 42 B. The first reflection area 42 A reflects a display image formed on the liquid crystal panel 22 as an image that serves as the basis for the virtual image PIC-A. The second reflection area 42 B reflects a display image formed on the liquid crystal panel 22 as an image that serves as the basis for the virtual image PIC-B.

[0091] The first and second reflective areas 42A and 42B are both horizontally elongated rectangular reflective areas. The first reflective area 42A is located above the second reflective area 42B. The first and second reflective areas 42A and 42B partially overlap. The first reflective area 42A is narrower in width than the second reflective area 42B.

[0092] The outer peripheral edge region 44 is formed with a substantially constant width so as to surround the effective reflection region 42. The left and right side portions 44a of the first reflection region 42A are wider than the other general regions. A pair of left and right vertical flange portions 46 are formed so as to extend obliquely downward from the left and right side portions 44a of the outer peripheral edge region 44 toward the front of the device.

[0093] Next, the operation of this embodiment will be described.

[0094] The image projection device 10 according to this embodiment is configured to project virtual images PIC-A and PIC-B on the image display section 106 by reflecting light emitted from the image generation unit 20 by a reflecting mirror 40. The reflecting mirror 40 includes an effective reflection area 42 that controls the reflection of the light emitted from the image generation unit 20, and an outer peripheral edge area 44 that surrounds the effective reflection area 42 over its entire periphery. The reflecting mirror 40 is formed so that the outer peripheral edge area 44 is thicker than the effective reflection area 42, and is supported at the outer peripheral edge area 44 by a first housing 52 and an actuator 70, which serve as reflecting mirror support members. Therefore, the image projection device 10 according to this embodiment can achieve the following effects.

[0095] Since the outer peripheral edge region 44 is formed to be thicker than the effective reflection region 42, it is possible to ensure the necessary rigidity without significantly increasing the weight of the reflecting mirror 40. This makes it possible to suppress deformation of the reflecting mirror 40 and maintain the optical function of the reflecting mirror 40.

[0096] The reflecting mirror 40 is supported at the outer peripheral edge region 44 by the first housing 52 and the actuator 70. This makes it possible to prevent the effective reflecting region 42 from being deformed in a way that would adversely affect the function of the reflecting mirror 40.

[0097] In this way, the image projection device of this embodiment is configured to project the display images generated by the image generation unit 20 as virtual images PIC-A and PIC-B on the image display section 106. According to this embodiment, in such an image projection device, even if the reflecting mirror 40 that reflects the light emitted from the image generation unit 20 toward the image display section 106 becomes large, it is possible to realize a lightweight and inexpensive configuration while ensuring the optical function of the reflecting mirror 40.

[0098] The image projection device of this embodiment is configured to project a virtual image PIC-A (first virtual image) in the lower region 106A of the image display unit 106 and a virtual image PIC-B (second virtual image) in the upper region 106B. The effective reflection area 42 of the reflecting mirror 40 includes a first reflection area 42A that reflects the display image that is the source of the virtual image PIC-A, and a second reflection area 42B that reflects the display image that is the source of the virtual image PIC-B. The first reflection area 42A is located above the second reflection area 42B and has a narrower left-right width than the second reflection area 42B. Furthermore, the reflecting mirror 40 is supported by the first housing 52 and the actuator 70 at both left and right portions 44a of the first reflection area 42A in the outer peripheral edge region 44. Therefore, the image projection device 10 of this embodiment can achieve the following effects.

[0099] When the effective reflection area 42 is configured such that the first reflection area 42A is an area above the second reflection area 42B and has a narrower left-to-right width than the second reflection area 42B, it becomes easy to ensure space for arranging a structure that supports the reflecting mirror 40 on both the left and right sides of the first reflection area 42A in the outer peripheral edge area 44. Therefore, by effectively utilizing this space, it becomes possible to ensure sufficient rigidity of the reflecting mirror 40 supported by the first housing 52 and the actuator 70.

[0100] The reflecting mirror 40 of this embodiment is configured as a concave mirror having a horizontally elongated rectangular outer shape, and since it is difficult to maintain the surface precision of the effective reflecting area 42, it is more effective to adopt the configuration of this embodiment.

[0101] Furthermore, the reflector 40 of this embodiment is supported so as to be rotatable around an axis Ax extending in the left-right direction relative to the first housing 52 and the actuator 70, and since this configuration makes it difficult to maintain the surface accuracy of the effective reflection area 42, it is even more effective to adopt the configuration of this embodiment.

[0102] In the above embodiment, the image generating unit 20 is described as having 12 light-emitting elements 24A and 12 light-emitting elements 24B, but it is also possible to configure it to have a different number of light-emitting elements 24A, 24B.

[0103] In the above embodiment, the image display unit 106 is described as being set on the inner surface of the front window 102, but it is also possible to configure the image display unit using a translucent plate or the like arranged on the inside of the passenger compartment of the front window 102.

[0104] In the above embodiment, the image projection device 10 has been described as being an in-vehicle head-up display, but it may also be used for other purposes.

[0105] Next, a modification of the first embodiment will be described.

[0106] First, a first modification of the first embodiment will be described.

[0107] 6A and 6B are views taken in the direction of the arrow II in FIG. 1, showing the configuration of the image projection device according to this modified example.

[0108] The basic configuration of the image projection device according to this modification is the same as that of the above embodiment, but the content of the control of the image projection device is partially different from that of the above embodiment.

[0109] 6A, when the vehicle speed is in the low-to-medium speed range, as in the above embodiment, a virtual image PIC-A is displayed as a first virtual image in the lower region 106A of the image display unit 106. In this modification, a virtual image PIC-C different from the virtual image PIC-B of the above embodiment is further displayed as a second virtual image in the upper region 106B as needed.

[0110] Specifically, as shown in FIG. 6B, when an emergency occurs, such as when a pedestrian or the like enters the road ahead of the vehicle, a virtual image PIC-C indicating the presence and direction of the pedestrian or the like is additionally displayed in the upper region 106B.

[0111] By adopting the configuration of this modified example, it is possible to further improve safety when the vehicle is traveling.

[0112] In this modified example, it is of course possible to configure the system so that when the vehicle speed reaches a high-speed range without an emergency occurring, a virtual image similar to the virtual image PIC-B in the above embodiment is displayed as a second virtual image in the upper region 106B.

[0113] Next, a second modification of the first embodiment will be described.

[0114] FIG. 7 is a view taken in the direction of the arrow V in FIG. 4, showing a reflecting mirror 240 of the image projection device according to this modified example.

[0115] Similar to the reflecting mirror 40 of the above embodiment, the reflecting mirror 240 of this modified example also includes an effective reflection area 242 and an outer peripheral edge area 244 that completely surrounds the effective reflection area 242. The outer peripheral edge area 244 is formed to be thicker than the effective reflection area 242. Furthermore, in this modified example, the configurations of the effective reflection area 242 and the outer peripheral edge area 244 are partially different from those in the above embodiment.

[0116] In this modification, a pair of left and right vertical flanges 246 are formed on the outer peripheral edge region 244 of the reflecting mirror 240 at both left and right side portions 244a of the first reflecting region 42A. Furthermore, in this modification, the effective reflecting region 242 is formed with a constant thickness. In addition, this modification differs from the above embodiment in that an annular rib 244b is formed on the outermost peripheral edge of the outer peripheral edge region 244, surrounding the effective reflecting region 242 over the entire circumference.

[0117] Even when the configuration of this modified example is adopted, substantially the same effects as those in the above embodiment can be obtained.

[0118] As in this modification, an annular rib 244b is additionally formed in the outer peripheral edge region 244 of the reflecting mirror 240. This makes it easier to ensure the rigidity required for the reflecting mirror 240 in the outer peripheral edge region 244 while maintaining the optical function required for the reflecting mirror 240 in the effective reflection region 242.

[0119] Next, a third modification of the first embodiment will be described.

[0120] FIG. 8 is a side cross-sectional view of an image projection device 310 according to this modified example.

[0121] The basic configuration of this modified example is the same as that of the above embodiment, but this modified example differs from the above embodiment in that light emitted from image generation unit 320 is sequentially reflected by first and second reflecting mirrors 340P and 340S toward image display unit 106.

[0122] Accordingly, the configuration and arrangement of the image generating unit 320 differ from those in the above embodiment, and the configuration of the housing 350 also differs in part from those in the above embodiment.

[0123] In this modification, the first reflecting mirror 340P is disposed in a rear region of the internal space 12, and the second reflecting mirror 340S is disposed in a front region of the internal space 12. The image generating unit 320 is supported by the first housing 352, positioned between the first reflecting mirror 340P and the second reflecting mirror 340S and below the first reflecting mirror 340P and the second reflecting mirror 340S.

[0124] Similar to the image generating unit 20 of the above embodiment, the image generating unit 320 includes a liquid crystal panel 322, a plurality of light emitting elements 324A and 324B, a lens member 328, a lens holder 330, and a heat sink 332. The image generating unit 320 is disposed facing the first reflecting mirror 340P. The image generating unit 320 has fewer light emitting elements 324A and 324B and convex lens portions 328A and 328B of the lens member 328 than the image generating unit 20 of the above embodiment.

[0125] The second reflecting mirror 340S has an effective reflecting area 342 and an outer peripheral area 344, similar to the reflecting mirror 40 of the above embodiment.

[0126] The first reflecting mirror 340P is located diagonally above and rearward of the image generating unit 320 and is configured to reflect light emitted from the image generating unit 320 forward. The reflecting surface 340Pa of the first reflecting mirror 340P has an outer shape that is horizontally elongated and rectangular when viewed from the front of the device. The horizontal cross-sectional shape of the reflecting surface 340Pa is configured as a convex curve, and the vertical cross-sectional shape of the reflecting surface 340Pa is configured as a concave curve.

[0127] First reflecting mirror 340P is configured to reflect light emitted from image generating unit 320 toward first reflecting region 342A of effective reflecting region 342 when multiple light-emitting elements 324A are lit. Furthermore, first reflecting mirror 340P is configured to reflect light emitted from image generating unit 320 toward second reflecting region 342B of effective reflecting region 342 when multiple light-emitting elements 324B are lit.

[0128] Even when the configuration of this modified example is adopted, substantially the same effects as those in the above embodiment can be obtained.

[0129] In a configuration in which the light emitted from the image generating unit 320 is reflected sequentially by the first and second reflecting mirrors 340P and 340S as in this modified example, the first reflecting mirror 340P may be configured to converge the light emitted from the image generating unit 320 further rearward of the device in the vertical direction than the second reflecting mirror 340S.

[0130] Hereinafter, the second embodiment of the present disclosure will be described with reference to the drawings.

[0131] (Second embodiment) Fig. 9 is a side cross-sectional view showing an image projection device 10X according to a second embodiment in a state where it is mounted on a vehicle 100. Fig. 10 is a view seen from the X direction arrow in Fig. 9. In the configuration shown in Fig. 9, the same components as those shown in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0132] As shown in Figures 9 and 10, the image projection device 10X of this embodiment is configured to project a virtual image PIC onto an image display unit 102A set on the inner surface of the front window 102 when placed inside the passenger compartment of a vehicle 100.

[0133] An optical path RX shown in FIG. 9 is an optical path taken by the driver 2 when visually perceiving the virtual image PIC projected on the image display unit 102A by the image projection device 10X.

[0134] The image display unit 102A is positioned in the lower region of the windshield 102 and in the region in front of the steering wheel 104, and has a horizontally long rectangular region, so that the driver 2 of the vehicle 100 can easily visually recognize the virtual image PIC displayed on the image display unit 102A.

[0135] FIG. 10 shows a specific example of the virtual image PIC in which the vehicle speed (50 km / h) is displayed together with a left-pointing arrow.

[0136] As shown in FIG. 9 , the image projection device 10X includes an image generation unit 20X, first and second reflecting mirrors 70X and 80X, a housing 50, and a light-transmitting cover 60. The image generation unit 20X generates a display image that serves as the basis for a virtual image PIC. The first and second reflecting mirrors 70X and 80X sequentially reflect light emitted from the image generation unit 20X toward an image display section 102A on the windshield 102. The housing 50 accommodates the image generation unit 20X and the first and second reflecting mirrors 70X and 80X. The light-transmitting cover 60 is attached to the housing 50.

[0137] The second housing 54X has an upper opening 54a formed therein, which transmits the light reflected by the second reflecting mirror 80X toward the image display unit 102A.

[0138] The light-transmitting cover 60 allows the light reflected from the second reflecting mirror 80X to be incident on the image display unit 102A, while ensuring that the internal space 12 of the housing 50 is dust-proof.

[0139] The image generating unit 20X and the first reflecting mirror 70X are disposed in a rear region of the internal space 12, and the second reflecting mirror 80X is disposed in a front region of the internal space 12. The reflecting surface 70aX of the first reflecting mirror 70X has a bilaterally symmetrical shape. The reflecting surface 80aX of the second reflecting mirror 80X has a bilaterally symmetrical shape. The image generating unit 20X is disposed at the center position of the first and second reflecting mirrors 70X, 80X in the left-right direction. The image generating unit 20X is supported by a lower wall portion 52bX of the first housing 52X (this will be described later).

[0140] The first reflecting mirror 70X is disposed substantially directly above the image generating unit 20X and is configured to reflect the light emitted from the image generating unit 20X forward. The reflecting surface 70aX of the first reflecting mirror 70X has an outer shape that is horizontally elongated and rectangular when viewed from the front of the device. The horizontal cross section of the reflecting surface 70aX is configured as a convex curve, and the vertical cross section of the reflecting surface 70aX is configured as a concave curve.

[0141] The second reflecting mirror 80X is disposed in front of the first reflecting mirror 70X. The second reflecting mirror 80X is configured to reflect the irradiation light from the image generating unit 20X, which is reflected by the first reflecting mirror 70X, upward.

[0142] The second reflecting mirror 80X is a concave mirror. The reflecting surface 80aX of the second reflecting mirror 80X is configured as a substantially spherical concave surface. The reflecting surface 80aX of the second reflecting mirror 80X has an outer shape of a horizontally elongated rectangle when viewed from the front of the device, and is formed to be larger in size than the reflecting surface 70aX of the first reflecting mirror 70X.

[0143] The second reflecting mirror 80X is supported rotatably about an axis Ax extending in the left-right direction relative to the first housing 52X. Specifically, the second reflecting mirror 80X has a pair of left and right flange portions 80b formed to protrude from both left and right ends of the second reflecting mirror 80X toward the back side of the reflecting surface 80aX. One of the flange portions 80b is connected to an actuator 82 fixed to the first housing 52X. The second reflecting mirror 80X rotates about the axis Ax when driven by the actuator 82, thereby enabling adjustment of the vertical position of the virtual image PIC formed on the image display unit 102A by light reflected from the second reflecting mirror 80X.

[0144] Next, the image generating unit 20X and its peripheral structure will be described.

[0145] 11 is a detailed view of the portion XI in FIG. 9, and FIG. 12 is a detailed view of the portion XII in FIG.

[0146] 11 and 12 , the image generating unit 20X includes a liquid crystal panel 22, an optical unit 30X, a panel support member 24, and a mask member 26X. The optical unit 30X irradiates the liquid crystal panel 22 with backlight from the rear side (i.e., the lower side) of the liquid crystal panel 22. The panel support member 24 supports the liquid crystal panel 22. The mask member 26X covers the outer peripheral edge region of the liquid crystal panel 22.

[0147] A diffusion plate 28X is disposed between the optical unit 30X and the liquid crystal panel 22 so as to extend along the lower surface of the liquid crystal panel 22. The diffusion plate 28X diffuses the light emitted from the optical unit 30X and makes it incident on the liquid crystal panel 22 as diffused light.

[0148] The liquid crystal panel 22 is disposed along a horizontal plane and is supported at its outer periphery by a panel support member 24 via a diffusion plate 28X.

[0149] The optical unit 30X includes a plurality of light-emitting elements 32X, a substrate 34 on which the plurality of light-emitting elements 32X are mounted, and a lens member 36 that controls the deflection of light emitted from the plurality of light-emitting elements 32X.

[0150] The plurality of light-emitting elements 32X are all white light-emitting diodes and are arranged in a grid pattern. Specifically, the plurality of light-emitting elements 32X are arranged in two locations at regular intervals in the front-rear direction and in five locations at equal intervals in the left-right direction, for a total of ten locations.

[0151] The substrate 34 is disposed along a horizontal plane so that the light emitting surfaces of the plurality of light emitting elements 32X face upward. The substrate 34 is supported on its lower surface by a heat sink 40X.

[0152] The heat sink 40X is made of a metal member such as aluminum, and includes a main body 40A extending in a flat plate shape along a horizontal plane, and a plurality of heat dissipation fins 40B extending downward at intervals in the left-right direction from the main body 40A.

[0153] The lens member 36 has a plurality of convex lens portions 36a formed on the upper surface of a horizontally elongated rectangular plate-like portion arranged along a horizontal plane. The plurality of convex lens portions 36a are formed in ten locations so as to be positioned directly above the plurality of light-emitting elements 32X. As a result, the plurality of convex lens portions 36a are configured to deflect the light emitted from each of the plurality of light-emitting elements 32X in a direction closer to directly above. The lens member 36 is supported by the panel support member 24 at the outer peripheral edge of the plate-like portion of the lens member 36.

[0154] The image generation unit 20X deflects light emitted from the plurality of light-emitting elements 32X using a lens member 36, and then causes the light to enter the liquid crystal panel 22 via a diffuser plate 28X. As a result, the image generation unit 20X is configured to generate a display image (i.e., an image that serves as the basis for the virtual image PIC) on the liquid crystal panel 22 with uniform brightness.

[0155] A recess 52b1 having an inner circumferential surface shape substantially identical to the outer shape of the main body 40A of the heat sink 40X is formed in the lower wall 52bX of the first housing 52X. A rectangular opening 52b2 is formed in the recess 52b1, through which the plurality of heat dissipation fins 40B are inserted.

[0156] The heat sink 40X is accommodated in a recess 52b1 in the lower wall 52bX of the first housing 52X with the heat dissipation fins 40B inserted into the openings 52b2. In this state, the main body 40A of the heat sink 40X is placed in the recess 52b1 around the openings 52b2.

[0157] The panel support member 24 is made of an opaque resin molded product and is positioned and fixed to the first housing 52X by fastening together with the heat sink 40X.

[0158] That is, a pair of front and rear tabs 24a extending laterally are formed on both the left and right sides of the panel support member 24. With the panel support member 24 placed on the main body 40A of the heat sink 40X, the two pairs of left and right tabs 24a are fastened with screws 42X via the main body 40A, thereby fixing the panel support member 24 to the bottom wall 52bX of the first housing 52X.

[0159] Fig. 13 is a perspective view showing the image generation unit 20X together with a heat sink 40X. Fig. 14 is an exploded perspective view showing the image generation unit 20X.

[0160] The mask member 26X is made of a material (specifically, a metal material such as aluminum) with a higher thermal conductivity than the liquid crystal panel 22. As shown in Figures 13 and 14, the mask member 26X includes a mask main body 26A, a pair of front and rear flanges 26B, and a pair of left and right flanges 26C. The mask main body 26A extends flat along a horizontal plane. The pair of front and rear flanges 26B extend directly downward from both front and rear edge portions of the mask main body 26A. The pair of left and right flanges 26C extend directly downward from both left and right edge portions of the mask main body 26A.

[0161] The pair of front and rear flanges 26B are formed across the entire width of the mask body 26A. The pair of left and right flanges 26C are formed at intermediate positions between the pair of front and rear tabs 24a.

[0162] The mask main body 26A has an opening 26Aa in the shape of a horizontally elongated rectangle that is slightly smaller than the liquid crystal panel 22. That is, the mask member 26X is configured to cover the outer peripheral edge region of the liquid crystal panel 22.

[0163] The mask member 26X is fixed to the panel support member 24 by caulking (specifically, by thermal caulking) at three locations: the center position in the left-right direction on the front side of the opening 26Aa, and both left and right end positions on the rear side of the opening 26Aa.

[0164] 14, crimping pins 24b are formed at the three locations on the upper surface of the panel support member 24. Pin insertion holes 26Ab, through which the crimping pins 24b are inserted, are formed at the three locations on the mask main body 26A. Of the three pin insertion holes 26Ab, the pin insertion hole located on the front side of the opening 26Aa is configured as a round hole, and the remaining two pin insertion holes are configured as elongated holes extending in the left-right direction.

[0165] A pair of left and right positioning pins 24c are formed in a position forward of the pair of left and right crimping pins 24b on the upper surface of the panel support member 24. A pair of left and right pin insertion holes 26Ac, through which the pair of left and right positioning pins 24c are inserted, are formed in the mask main body 26A. Each of the pair of left and right pin insertion holes 26Ac is formed as an elongated hole extending in the front-to-rear direction.

[0166] The three crimping pins 24b are inserted into the three pin insertion holes 26Ab, and the pair of left and right positioning pins 24c are inserted into the pair of left and right pin insertion holes 26Ac. In this state, the tips of the three crimping pins 24b are heated and crushed, thereby thermally crimping the mask member 26X to the panel support member 24, as shown in FIG.

[0167] By performing such thermal caulking, the mask member 26X is positioned in the horizontal plane relative to the panel support member 24. Furthermore, in this state, the lower end surfaces of the pair of front and rear flange portions 26B and the pair of left and right flange portions 26C abut against the upper surface of the main body portion 40A of the heat sink 40X.

[0168] Next, the operation of this embodiment will be described.

[0169] The image projection device 10X according to this embodiment includes an image generation unit 20X that generates a virtual image PIC to be projected on the image display unit 102A. Specifically, the image projection device 10X includes, as the image generation unit 20X, a liquid crystal panel 22, an optical unit 30X that irradiates the liquid crystal panel 22 with backlight, a panel support member 24 that supports the liquid crystal panel 22, and a mask member 26X that covers the outer peripheral edge region of the liquid crystal panel 22. Therefore, the image projection device 10X according to this embodiment can achieve the following effects.

[0170] The image projection device 10X can define the use area of ​​the liquid crystal panel 22 by disposing the mask member 26X. Furthermore, even if sunlight S enters the internal space 12 of the image projection device 10X as shown in Fig. 9, the light-blocking function of the mask member 26X makes it possible to suppress the temperature rise of the liquid crystal panel 22 to a certain extent.

[0171] Furthermore, in the image projection device 10X according to this embodiment, the heat sink 40X on which the optical unit 30X is mounted is fixed to the panel support member 24. Furthermore, the mask member 26X is made of a material having a higher thermal conductivity than the liquid crystal panel 22, and is fixed to the panel support member 24 while being disposed so as to be in contact with the heat sink 40X. Therefore, the image projection device 10X according to this embodiment can obtain the following effects.

[0172] Even if the temperature of the liquid crystal panel 22 rises due to backlight irradiation from the optical unit 30X or sunlight irradiation, the heat can be released to the heat sink 40X via the mask member 26X, which has a higher thermal conductivity than the liquid crystal panel 22. This effectively prevents the liquid crystal panel 22 from overheating. Furthermore, the output of the optical unit 30X can be increased while maintaining the functionality of the liquid crystal panel 22.

[0173] Moreover, the image projection device 10X according to this embodiment can achieve the above-described effects by not using a dedicated heat transfer panel but by utilizing the mask member 26X that defines the use area of ​​the liquid crystal panel 22. Therefore, according to this embodiment, it is possible to generate a bright virtual image PIC while suppressing the cost of the image projection device 10X.

[0174] Thus, according to this embodiment, in the image projection device 10X configured to project the display image generated by the image generation unit 20X as a virtual image PIC on the image display section 102A, it is possible to generate a bright virtual image PIC while suppressing the cost of the image projection device 10X.

[0175] In this embodiment, the mask member 26X is fixed to the panel support member 24 by caulking, and therefore the following advantageous effects can be obtained.

[0176] According to this embodiment, the number of parts of the image projection device 10X can be reduced compared to fixing by screw fastening or the like.

[0177] Furthermore, compared to fixation by lance engagement or the like, excessive load is less likely to be placed on the liquid crystal panel 22, and gaps that could cause vibration of the mask member 26X to occur inadvertently between the panel support member 24 and the mask member 26X can be prevented.

[0178] Moreover, in this embodiment, the panel support member 24 is made of a resin material, and the mask member 26X is fixed to the panel support member 24 by thermal caulking, which makes the fixing easier than with cold caulking.

[0179] The image projection device 10X according to this embodiment includes first and second reflecting mirrors 70X and 80X that sequentially reflect light emitted from the image generation unit 20X toward the image display unit 102A. The second reflecting mirror 80X is configured as a concave mirror, so that sunlight S entering the internal space 12 of the image projection device 10X is easily focused on the edge of the liquid crystal panel 22 by being sequentially reflected by the second reflecting mirror 80X and the first reflecting mirror 70X, as shown in FIG. 9 . Therefore, as in this embodiment, it is particularly effective to suppress a rise in temperature of the liquid crystal panel 22 by using the light-shielding function of the mask member 26X arranged to cover the outer peripheral region of the liquid crystal panel 22.

[0180] In the above embodiment, the optical unit 30X is described as having ten light-emitting elements 32X and a lens member 36 having ten convex lens portions 36a, but it is also possible to configure the optical unit 30X to have a number of light-emitting elements 32X and convex lens portions 36a other than this.

[0181] In the above embodiment, the mask member 26X is fixed to the panel support member 24 by thermal caulking, but it is also possible to use cold caulking. By adopting such a configuration, it becomes easy to use a metal member or the like as the panel support member 24.

[0182] In the above embodiment, the first and second reflecting mirrors 70X and 80X are provided, but it is also possible to use a configuration that includes only the second reflecting mirror 80X. It is also possible to use a configuration in which the light emitted from the image generating unit 20X is directly incident on the image display unit 102A.

[0183] In the above embodiment, the image display unit 102A is described as being set on the inner surface of the front window 102, but it is also possible to configure the image display unit using a translucent plate or the like arranged on the inside of the passenger compartment of the front window 102.

[0184] Next, a modification of the second embodiment will be described.

[0185] FIG. 15 is a perspective view showing the image generating unit 120 of the image projection device according to this modified example together with a heat sink.

[0186] The image generating unit 120 of this modified example also has the same basic configuration as that of the above embodiment, but the configuration of the mask member 126 is different from that of the above embodiment.

[0187] Similar to the mask member 26X of the above embodiment, the mask member 126 of this modification is also made of a metal member including a mask main body 126A, a pair of front and rear flanges 126B, and a pair of left and right flanges 126C. This modification further differs from the above embodiment in that openings 126Aa1 and 126Aa2 are formed in two locations on the mask main body 126A.

[0188] Specifically, the opening 126Aa1 is formed at a position closer to the front of the mask main body 126A, and the opening 126Aa2 is formed at a position closer to the rear of the mask main body 126A. Both the openings 126Aa1 and 126Aa2 are formed with a left-to-right width narrower than the liquid crystal panel 22. The opening 126Aa1 is formed with a left-to-right width narrower than the opening 126Aa2, and also with a front-to-back width narrower than the opening 126Aa2.

[0189] As a result, the mask member 126 has a beam-shaped portion 126Ad formed therein, which extends in the left-right direction between the two openings 126Aa1 and 126Aa2 in the mask main body 126A.

[0190] Even when the configuration of this modified example is adopted, the same effects as those of the above embodiment can be obtained.

[0191] Furthermore, in this modification, the openings 126Aa1 and 126Aa2 are formed in two places in the mask member 126, and thus the following advantageous effects can be obtained.

[0192] A beam-like portion 126Ad is formed between the two openings 126Aa1 and 126Aa2 in the mask member 126. This increases the rigidity of the mask member 126 and allows the heat generated by the liquid crystal panel 22 to be conducted to the heat sink 40X more efficiently.

[0193] Furthermore, in this modification, use areas are set in two places on the liquid crystal panel 22. This allows two types of virtual images PIC to be displayed in two places on the image display unit 102A.

[0194] Specifically, in this modification, the opening 126Aa1 formed in a position closer to the front defines the usable area of ​​the liquid crystal panel 22, thereby enabling the virtual image PIC to be formed in the lower area of ​​the image display unit 102A. Furthermore, in this modification, the opening 126Aa2 formed in a position closer to the rear defines the usable area of ​​the liquid crystal panel 22, thereby enabling the virtual image PIC to be formed in the upper area of ​​the image display unit 102A.

[0195] Even when the configuration of this modified example is adopted, the same effects as those of the above embodiment can be obtained.

[0196] It should be noted that the numerical values ​​shown as the specifications in the above embodiment and its modified examples are merely examples, and it goes without saying that these may be set to different values ​​as appropriate.

[0197] Furthermore, the present disclosure is not limited to the configurations described in the above-described embodiment and its modified examples, and configurations with various other modifications can be adopted.

[0198] The configurations described in the items listed below also constitute part of the present disclosure. Item 1: An image projection device configured to project a display image generated by an image generation unit as a virtual image on an image display section, the image projection device comprising: a reflecting mirror that reflects light emitted from the image generation unit toward the image display section, and a reflecting mirror support member that supports the reflecting mirror, the reflecting mirror having an effective reflection area that controls the reflection of the light emitted from the image generation unit, and an outer circumferential edge area that surrounds the effective reflection area over its entire periphery, the outer circumferential edge area being thicker than the effective reflection area, and the reflecting mirror being supported by the reflecting mirror support member at the outer circumferential edge area. Item 2: The image projection device according to Item 1, wherein the image projection device is configured to project a first virtual image in a lower region of the image display unit and a second virtual image in an upper region as the virtual image, the effective reflection area includes a first reflection area that reflects a display image that is the source of the first virtual image and a second reflection area that reflects a display image that is the source of the second virtual image, the first reflection area being an area above the second reflection area and having a narrower left-right width than the second reflection area, and the reflecting mirror is supported by the reflecting mirror support member at both left and right portions of the first reflection area in the outer peripheral edge region. Item 3: The image projection device according to Item 1 or 2, wherein the effective reflection area is formed with a constant thickness, and the outer peripheral edge region includes an annular rib formed to surround the effective reflection area over its entire circumference. Item 4: The image projection device according to any one of Items 1 to 3, wherein the reflecting mirror is configured as a concave mirror having a horizontally elongated rectangular outer shape. Item 5: The image projection device according to any one of Items 1 to 4, wherein the reflecting mirror is supported rotatably about an axis extending in the left-right direction relative to the reflecting mirror support member.Item 6: An image projection device configured to project a display image generated by an image generation unit as a virtual image on an image display section, wherein the image generation unit includes a liquid crystal panel, an optical unit that irradiates the liquid crystal panel with backlight, a panel support member that supports the liquid crystal panel, and a mask member that covers an outer peripheral edge region of the liquid crystal panel, wherein the optical unit is mounted on a heat sink fixed to the panel support member, and the mask member is made of a material having a higher thermal conductivity than the liquid crystal panel and is fixed to the panel support member while being disposed so as to be in contact with the heat sink. Item 7: The image projection device according to Item 6, wherein the mask member is fixed to the panel support member by crimping. Item 8: The image projection device according to Item 7, wherein the panel support member is made of a resin material, and the crimping is performed by thermal crimping. Item 9: The image projection device according to any one of Items 6 to 8, wherein openings are formed in two locations on the mask member. Item 10: The image projection device according to any one of Items 6 to 9, further comprising a concave mirror that reflects light emitted from the image generation unit toward the image display section.

[0199] This application claims priority based on Japanese Application No. 2023-185241 filed on October 30, 2023 and Japanese Application No. 2023-171169 filed on October 2, 2023, and incorporates all of the contents of the aforementioned Japanese applications.

Claims

1. An image projection device configured to project a display image generated by an image generating unit onto an image display section as a virtual image, comprising: a reflector that reflects light emitted from the image generating unit towards the image display section; and a reflector support member that supports the reflector, wherein the reflector has an effective reflection area that controls the reflection of the light emitted from the image generating unit, and an outer circumferential edge area that completely surrounds the effective reflection area, the outer circumferential edge area being formed to be thicker than the effective reflection area, and the reflector is supported by the reflector support member at the outer circumferential edge area.

2. The image projection device according to claim 1, wherein the image projection device is configured to project a first virtual image onto a lower region of the image display unit and a second virtual image onto an upper region as the virtual image, the effective reflective area includes a first reflective area that reflects an image for display that is the source of the first virtual image and a second reflective area that reflects an image for display that is the source of the second virtual image, and the first reflective area is an area above the second reflective area that is narrower in left-right width than the second reflective area, and the reflector is supported by the reflector support member at both left and right sides of the first reflective area in the outer peripheral area.

3. An image projection device as described in claim 1 or 2, wherein the effective reflection area is formed with a constant thickness, and the outer peripheral edge area is provided with an annular rib formed so as to surround the entire effective reflection area.

4. The image projection device according to claim 1 or 2, wherein the reflecting mirror is configured as a concave mirror having an outer shape of a horizontally elongated rectangle.

5. The image projection device according to claim 1 or 2, wherein said reflecting mirror is supported rotatably about an axis extending in the left-right direction relative to said reflecting mirror supporting member.

6. An image projection device configured to project a display image generated by an image generation unit as a virtual image on an image display section, the image generation unit comprising a liquid crystal panel, an optical unit that irradiates the liquid crystal panel with backlight, a panel support member that supports the liquid crystal panel, and a mask member that covers the outer peripheral region of the liquid crystal panel, the optical unit being mounted on a heat sink fixed to the panel support member, and the mask member being made of a material having a higher thermal conductivity than the liquid crystal panel and being fixed to the panel support member while being positioned so as to be in contact with the heat sink.

7. The image projection device according to claim 6, wherein said mask member is fixed to said panel support member by caulking.

8. The image projection device according to claim 7, wherein the panel support member is made of a resin material, and the crimping is performed by thermal crimping.

9. The image projection device according to claim 6 or 7, wherein openings are formed in two places of said mask member.

10. The image projection device according to claim 6 or 7, further comprising a concave mirror that reflects the light emitted from said image generating unit towards said image display section.

Images