Image projection device

Abstract

Provided is an image irradiation device configured to project a display image on an image display part by using first and second reflection mirrors to sequentially reflect light emitted from an image generation unit, wherein a heat radiation function of the image generation unit can be improved. In a lower wall part 52b of a first housing 52, a region positioned below an intermediate position of first and second reflection mirrors 70, 80 is configured as an inclined surface part 52bB that is inclined downward toward the rear of the device, and an image generation unit 20 is supported on the inclined surface part 52bB via a heat sink 40. In this case, the heat sink 40 is configured such that a plurality of heat radiation fins 40B extending from the lower surface of a body part 40A of the heat sink are inserted into a plurality of fin insertion holes 52c formed in the lower wall part 52b, and front end surfaces 40Ba of the plurality of heat radiation fins 40B are formed so as to extend in a downward direction with respect to the surface perpendicular direction of the inclined surface part 52bB.

Description

Image projection device

[0001] The present invention relates to an image projection device configured to project a display image on an image display unit.

[0002] Conventionally, there has been known an in-vehicle image projection device that is configured to project a display image onto an image display section such as a front window (i.e., windshield) or a light-transmitting plate arranged inside the vehicle cabin when placed inside the vehicle cabin.

[0003] Patent Document 1 describes such an image projection device as comprising an image generation unit that generates an image for display, and first and second reflecting mirrors that sequentially reflect the light emitted from the image generation unit toward the image display section.

[0004] In the image projection device described in Patent Document 1, the image generation unit and the first and second reflecting mirrors are accommodated in a housing.

[0005] Japanese Patent Application Laid-Open No. 2021-162704

[0006] In order to enhance the heat dissipation function of the image generating unit in such an image projection device, it is preferable that the image generating unit is supported on the outer wall of the housing via a heat sink, and that the heat sink is provided with a plurality of heat dissipation fins, which are inserted into fin insertion holes formed on the outer wall of the housing.

[0007] Furthermore, in order to configure the housing of such an image projection device compactly, it is preferable to position the image generation unit diagonally upward and toward the rear of the device so that the emitted light can easily enter the first reflector located at the rear of the device.

[0008] However, in this case, it is necessary to form a portion of the lower wall of the housing as an inclined surface that slopes downward toward the rear of the device, and to form fin insertion holes in this inclined surface for inserting the multiple heat dissipation fins. In this case, the multiple heat dissipation fins extend perpendicular to the surface of the inclined surface toward the space below the housing, forming a narrow wedge-shaped space between the area of ​​the lower wall of the housing that is located toward the front of the device and the front end surfaces of the multiple heat dissipation fins, causing heat to accumulate in this space. This ultimately reduces the heat dissipation function of the image generation unit.

[0009] It should be noted that such a problem can also occur in image projection devices other than those mounted on vehicles.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide an image projection device that can enhance the heat dissipation function of an image generation unit in an image projection device that is configured to project a display image on an image display unit by sequentially reflecting light emitted from an image generation unit by first and second reflecting mirrors.

[0011] The present invention is intended to achieve the above object by devising a heat sink structure.

[0012] That is, the image projection device according to the present invention is an image projection device configured to project a display image on an image display section, comprising: an image generation unit that generates the display image; first and second reflecting mirrors that sequentially reflect light emitted from the image generation unit toward the image display section; and a housing that accommodates the image generation unit and the first and second reflecting mirrors, wherein the first reflecting mirror is disposed rearward of the device than the second reflecting mirror, and the image generation unit is supported by a lower wall portion of the housing via a heat sink in a state where it is disposed between the first reflecting mirror and the second reflecting mirror and lower than the first and second reflecting mirrors, and the lower wall portion of the housing is configured as an inclined surface portion that is inclined downward toward the rear of the device in an area located below an intermediate position between the first and second reflecting mirrors, The heat sink comprises a main body portion supporting the image generating unit and a plurality of heat dissipation fins formed to extend downward from the main body portion in the front-to-rear direction of the device, and is arranged with the plurality of heat dissipation fins inserted into fin insertion holes formed in the inclined surface portion, and the heat sink is characterized in that the front end surfaces of the plurality of heat dissipation fins are formed to extend downward relative to the surface perpendicular to the inclined surface portion.

[0013] The above-mentioned "image projection device" is not particularly limited in its specific use as long as it is configured to project a display image on an image display unit, and can be used, for example, as an in-vehicle head-up display.

[0014] The specific configuration of the above-mentioned "image display unit" is not particularly limited as long as it is configured to display an image for display, and for example, a translucent plate placed on the front window of a vehicle or the inside of the passenger compartment can be used.

[0015] The above-mentioned "first and second reflectors" are not particularly limited in their specific arrangement or shape of the reflecting surface, as long as the first reflector is positioned further rearward of the device than the second reflector and is configured to sequentially reflect light emitted from the image generating unit toward the image display unit.

[0016] The "inclined surface portion" is inclined downward toward the rear of the device, but the specific angle of inclination is not particularly limited.

[0017] The "plurality of heat dissipating fins" are not particularly limited in terms of the specific direction, as long as their front end surfaces are formed to extend downward relative to the plane perpendicular to the inclined surface portion.

[0018] The image projection device of the present invention is configured to project a display image onto the image display unit by sequentially reflecting light emitted from the image generating unit by the first and second reflecting mirrors, and the image generating unit is supported on the lower wall of the housing via a heat sink below the midpoint between the first and second reflecting mirrors, and the heat sink is arranged with multiple heat dissipation fins inserted into fin insertion holes formed in the lower wall, thereby making it easy to ensure the heat dissipation function of the image generating unit.

[0019] In this case, the lower wall portion of the housing, in the area located below the midpoint between the first and second reflectors, is configured as an inclined surface portion that slopes downward toward the rear of the device, making it easy to position the image generating unit diagonally upward toward the rear of the device so that its emitted light is incident on the first reflector, thereby allowing the housing to be configured compactly.

[0020] Furthermore, the heat sink of the present invention is formed so that the front end faces of the plurality of heat dissipating fins extend downward relative to the plane perpendicular to the inclined surface portion, and therefore the following advantageous effects can be obtained.

[0021] In other words, if the front end faces of the multiple heat dissipation fins extend perpendicular to the surface of the inclined surface portion, a narrow wedge-shaped space will be formed between the area of ​​the lower wall portion of the housing located on the front side of the inclined surface portion of the device and the front end faces of the multiple heat dissipation fins, and heat will accumulate in this space, thereby reducing the heat dissipation function of the image generation unit.

[0022] In contrast, in the present invention, the front end faces of the heat dissipation fins extend downward relative to the direction perpendicular to the inclined surface, so a space with a wide angle can be secured between the area of ​​the lower wall of the housing located on the front side of the inclined surface and the front end faces of the heat dissipation fins, making it less likely that heat will accumulate in this space, thereby improving the heat dissipation function of the image generation unit.

[0023] Thus, according to the present invention, in an image projection device configured to project a display image on an image display unit by sequentially reflecting light emitted from an image generation unit by first and second reflecting mirrors, the heat dissipation function of the image generation unit can be improved.

[0024] In the above configuration, if the lower wall of the housing has a horizontal surface in the region below the second reflector, and the angle of inclination of the connecting region between the horizontal surface and the inclined surface is gradually changed, it becomes possible to easily form a larger space between the front end surfaces of the plurality of heat dissipation fins and the region in the lower wall of the housing that is located on the front side of the inclined surface, which makes it more difficult for heat to accumulate in the space below the housing and facilitates convection along the lower surface of the lower wall in the space below the housing, thereby further improving the heat dissipation function of the image generation unit.

[0025] In this case, with regard to the configuration of the heat sink, if the front region of its main body is formed to extend along the connection region between the horizontal surface portion and the inclined surface portion of the lower wall portion of the housing, the positioning accuracy of the heat sink relative to the housing can be improved and the heat dissipation function of the image generating unit can be enhanced.

[0026] In the above configuration, if the heat sink is further configured so that the rear end faces of the multiple heat dissipation fins extend downward relative to the surface perpendicular to the inclined surface portion, the multiple heat dissipation fins can be formed with a larger volume within a range that allows them to be easily inserted into the fin insertion holes of the inclined surface portion, thereby increasing the heat capacity and improving the heat dissipation function.

[0027] In the above configuration, if the heat sink is further configured so that the lower end surfaces of the multiple heat dissipation fins extend along a horizontal plane, the amount of downward protrusion of the multiple heat dissipation fins can be minimized while maximizing their thermal capacity.

[0028] In the above configuration, if the first reflector is further configured to converge the light emitted from the image generating unit further rearward of the device than the second reflector in the vertical direction, the image generating unit can be positioned at a higher position within a range where the reflected light from the first reflector is not blocked, thereby making the housing even more compact.

[0029] 1 is a detailed view of part III in FIG. 1; FIG. 3 is a cross-sectional view taken along line IV-IV in FIG. 3; (a) is an enlarged view of a main part of FIG. 3, and (b) is a view similar to (a) showing a comparative example of the above embodiment; (b) is a view similar to FIG. 4 showing a first modified example of the above embodiment; and (c) is a view similar to FIG. 1 showing a second modified example of the above embodiment.

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0031] Fig. 1 is a side cross-sectional view showing an image projection device 10 according to an embodiment of the present invention, mounted on a vehicle 100. Fig. 2 is a view taken in the direction of the arrow II in Fig. 1 .

[0032] 1 and 2, 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 other figures than FIGS. 1 and 2.

[0033] As shown in FIGS. 1 and 2 , the image projection device 10 according to this embodiment is an in-vehicle head-up display, and is configured to project a display image PIC as a virtual image on an image display unit 102A set on the inner surface of a front windshield 102 when placed in the passenger compartment of a vehicle 100.

[0034] An optical path R shown in FIG. 1 is an optical path taken by the driver 2 when visually perceiving the display image PIC projected on the image display unit 102A by the image projection device 10.

[0035] The image display unit 102A is set as a horizontally long rectangular area located below the windshield 102 and in front of the steering wheel 104. This allows the driver 2 of the vehicle 100 to easily visually recognize the display image PIC displayed on the image display unit 102A.

[0036] In addition, FIG. 2 shows a specific example of the display image PIC in which the vehicle speed (50 km / h) is displayed together with a left-pointing arrow.

[0037] 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 .

[0038] As shown in FIG. 1, the image projection device 10 includes an image generation unit 20 that generates a display image that is the basis for the display image PIC, first and second reflectors 70, 80 that sequentially reflect the light emitted from the image generation unit 20 toward the image display section 102A of the front windshield 102, a housing 50 that accommodates these, and a light-transmitting cover 60 attached to the housing 50.

[0039] The housing 50 is configured such that a second housing 54 is assembled to a first housing 52 formed to open upward.

[0040] FIG. 3 is a detailed view of part III in FIG.

[0041] 3, the second housing 54 has an outer peripheral flange 54b, and is assembled to the first housing 52 with the outer peripheral flange 54b in contact with the upper end opening of the peripheral wall 52a of the first housing 52. The second housing 54 is formed with an opening 54a that allows reflected light from the second reflecting mirror 80 to pass through toward the image display unit 102A.

[0042] The first and second housings 52, 54 are made of opaque resin molded parts, but the light-transmitting cover 60 is made of a colorless, transparent resin panel.

[0043] The light-transmitting cover 60 is arranged in a state where it is curved downward and tilted slightly upward toward the rear so as to cover the opening 54a of the second housing 54. The light-transmitting cover 60 allows reflected light from the second reflecting mirror 80 to be incident on the image display unit 102A, while ensuring dustproofness of the internal space 12 of the housing 50. The second housing 54 is formed with a light-blocking piece 54c that extends diagonally downward and forward from the rear edge of the upper opening 54a toward the internal space 12.

[0044] The first reflecting mirror 70 is disposed in the rear region of the interior space 12, and the second reflecting mirror 80 is disposed in the front region of the interior space 12. The image generating unit 20 is disposed between the first reflecting mirror 70 and the second reflecting mirror 80, at a position lower than these mirrors.

[0045] The first and second reflecting mirrors 70, 80 have reflecting surfaces 70a, 80a each having a symmetrical outer shape, and the image generating unit 20 is disposed at the center in the left-right direction.

[0046] The first reflecting mirror 70 is located diagonally above and rearward of the image generating unit 20, and is configured to reflect light emitted from the image generating unit 20 forward. The reflecting surface 70a of this first reflecting mirror 70 has an outer shape that is horizontally elongated and rectangular when viewed from the front of the device, and its horizontal cross section is configured as a convex curve, and its vertical cross section is configured as a concave curve.

[0047] The second reflecting mirror 80 is configured to reflect upward the light emitted from the image generating unit 20 that has been reflected by the first reflecting mirror 70. The second reflecting mirror 80 is a concave mirror, and its reflecting surface 80a has an outer shape that is horizontally elongated and rectangular when viewed from the front of the device, and is formed to be larger in size than the reflecting surface 70a of the first reflecting mirror 70.

[0048] The first reflecting mirror 70 is fixedly supported by the first housing 52 via a support structure (not shown).

[0049] The second reflecting mirror 80 is supported rotatably about an axis Ax extending in the left-right direction relative to the first housing 52. Specifically, the second reflecting mirror 80 has a pair of left and right flange portions 80b formed to protrude from both left and right ends thereof toward the rear side of the reflecting surface 80a, and one of the flange portions 80b is connected to an actuator 82 fixed to the first housing 52. The second reflecting mirror 80 rotates about the axis Ax when driven by the actuator 82, thereby making it possible to adjust the vertical position of the display image PIC formed on the image display unit 102A by the light reflected from the second reflecting mirror 80.

[0050] The image generating unit 20 is supported on the lower wall portion 52 b of the first housing 52 via the heat sink 40 .

[0051] The lower wall 52b of the first housing 52 is configured as an inclined surface 52bB that is inclined downward toward the rear of the device in an area located below the midpoint between the first and second reflecting mirrors 70, 80. Specifically, the downward inclination angle of the inclined surface 52bB is set to a value of approximately 30 to 50 degrees.

[0052] In addition, the lower wall portion 52b of the first housing 52 is configured such that the area located further forward from the lamp than the inclined surface portion 52bB is configured as a horizontal surface portion 52bA extending along an approximately horizontal plane, and the area located further rearward from the lamp than the inclined surface portion 52bB is configured as an inverted inclined surface portion 52bC that is inclined upward toward the rear of the device.

[0053] Furthermore, the lower wall portion 52b of the first housing 52 is formed so that the angle of inclination gradually changes at a connection region 52b1 that connects the horizontal surface portion 52bA and the inclined surface portion 52bB. Specifically, this connection region 52b1 is formed so as to extend along a convex cylindrical surface that extends in the left-right direction.

[0054] The image generating unit 20 comprises a liquid crystal panel 22 and an optical unit 30 configured to illuminate the liquid crystal panel 22 from its rear side with backlight, and is configured to generate a display image (i.e., an image that serves as the basis for the display image PIC) on the liquid crystal panel 22 using the backlight illumination light.

[0055] The optical unit 30 includes a light-emitting element 32 as a light source, a substrate 34 on which the light-emitting element 32 is mounted, a lens 36 that controls the deflection of the light emitted from the light-emitting element 32, and a lens holder 38 that supports the lens 36.

[0056] The lens 36 is formed in a biconvex lens shape, and its outer peripheral flange is supported by the lens holder 38. The substrate 34 is supported on its underside by the heat sink 40, with the substrate 34 being arranged parallel to the inclined surface portion 52bB so that the light-emitting surface of the light-emitting element 32 faces diagonally upward and rearward.

[0057] The liquid crystal panel 22 has a horizontally elongated rectangular outer shape, and is supported by the lens holder 38 of the image generating unit 20 in a state where it is disposed so as to extend parallel to the inclined surface portion 52bB.

[0058] The lens holder 38 is fixed at both left and right ends thereof together with the heat sink 40 to the first housing 52 by means of screws or the like.

[0059] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

[0060] As also shown in FIG. 4, the heat sink 40 includes a main body 40A and a plurality of heat dissipation fins 40B.

[0061] The main body 40A is formed so as to extend flatly along the upper surface of the inclined surface portion 52bB of the lower wall portion 52b of the first housing 52, but its front region 40Aa is formed so as to extend curvedly along the connection region 52b1 of the first housing 52.

[0062] The heat dissipation fins 40B are formed on the underside of the main body 40A at equal intervals in the left-right direction, extending along a vertical plane in the front-to-rear direction of the device. The front end faces 40Ba and rear end faces 40Bb of the heat dissipation fins 40B extend downward relative to the plane perpendicular to the inclined surface 52bB. Specifically, the front end faces 40Ba and rear end faces 40Bb are both formed to extend along a vertical plane perpendicular to the front-to-rear direction of the device. The bottom end faces 40Bc of the heat dissipation fins 40B extend along a horizontal plane.

[0063] A plurality of fin insertion holes 52c are formed in the inclined surface portion 52bB of the first housing 52 at equal intervals in the left-right direction and extending in the front-rear direction of the device. Each fin insertion hole 52c has a rectangular opening shape that extends elongatedly in the front-rear direction of the device in a plan view. Each fin insertion hole 52c has a left-right width that is slightly wider than the thickness of each heat dissipation fin 40B and a front-rear width that is slightly wider than the front-rear width of each heat dissipation fin 40B, and the front and rear end faces of each fin insertion hole 52c are formed to extend along a vertical plane.

[0064] The heat sink 40 is positioned relative to the first housing 52 by inserting the heat dissipation fins 40B into the fin insertion holes 52c from above, whereby the lower surface of the main body 40A is placed in surface contact with the upper surface of the inclined surface 52bB. At this time, the front region 40Aa of the main body 40A of the heat sink 40 and the connection region 52b1 of the lower wall 52b of the first housing 52 are in surface contact in a curved state, thereby improving the positioning accuracy of the heat sink 40.

[0065] Next, the operation of this embodiment will be described.

[0066] The image projection device 10 of this embodiment is configured to display a display image PIC on the image display section 102A by sequentially reflecting light emitted from the image generation unit 20 by the first and second reflectors 70, 80. The image generation unit 20 is supported on the lower wall portion 52b of the first housing 52 via a heat sink 40 below the midpoint between the first and second reflectors 70, 80, and the heat sink 40 is arranged with multiple heat dissipation fins 40B inserted into multiple fin insertion holes 52c formed in the lower wall portion 52b, thereby making it easy to ensure the heat dissipation function of the image generation unit 20.

[0067] In this case, the lower wall portion 52b of the first housing 52, in the area located below the midpoint between the first and second reflectors 70, 80, is configured as an inclined surface portion 52bB that slopes downward toward the rear of the device, making it easy to position the image generating unit 20 diagonally upward toward the rear of the device so that its emitted light is incident on the first reflector 70, thereby enabling the housing 50 to be configured compactly.

[0068] Furthermore, in the heat sink 40 of this embodiment, the front end surfaces 40Ba of the plurality of heat dissipation fins 40B are formed so as to extend downward relative to the direction perpendicular to the inclined surface portion 52bB, thereby achieving the following advantageous effects, which will be described with reference to FIG.

[0069] Fig. 5(a) is an enlarged view of a main part of Fig. 3. Fig. 5(b) is a view similar to Fig. 5(a) showing a comparative example of this embodiment.

[0070] The comparative example shown in Figure 5(b) differs from the present embodiment in that the configuration of the first housing 52' is partially different from that of the present embodiment, and also in that the image generation unit 20 is supported on the lower wall portion 52b' of the first housing 52' via a heat sink 40' instead of the heat sink 40 of the present embodiment.

[0071] That is, in the first housing 52' of this comparative example, the lower wall portion 52b' has an inclined surface portion 52bB' and a horizontal surface portion 52bA' similar to those of this embodiment, but there is no connection area 52b1 formed between the two in which the inclination angle gradually changes as in this embodiment.

[0072] Similarly to the heat sink 40 of this embodiment, the heat sink 40' of this comparative example also includes a main body 40A' and a plurality of heat dissipation fins 40B'.

[0073] In the heat sink 40' of this comparative example, the main body portion 40A' is formed to extend in a flat plate shape along the upper surface of the inclined surface portion 52bB' of the first housing 52', but a front region 40Aa like the heat sink 40 of this embodiment is not formed.

[0074] Furthermore, in the heat sink 40' of this comparative example, the plurality of heat dissipation fins 40B' are formed to extend obliquely downward and forward from the main body 40A' (specifically, in the direction perpendicular to the surface of the inclined surface 52bB') in a rectangular shape. The plurality of heat dissipation fins 40B' are inserted obliquely upward and rearward into the plurality of fin insertion holes 52c' formed in the inclined surface 52bB' of the first housing 52'.

[0075] As a result, the front end surfaces 40Ba' of the heat dissipation fins 40B' extend perpendicular to the inclined surface portion 52bB', forming a narrow wedge-shaped space S' between the horizontal surface portion 52bA' of the first housing 52' and the front end surfaces 40Ba' of the heat dissipation fins 40B'. Heat accumulates in this space S', reducing the heat dissipation function of the image generation unit 20.

[0076] In this comparative example, in order to enable molding of the first housing 52, the multiple fin insertion holes 52c' formed in the inclined surface portion 52bB' are formed so that their front end faces extend vertically and their rear end faces extend diagonally upward.

[0077] 5(a), in the heat sink 40 of this embodiment, the front end surfaces 40Ba of the plurality of heat dissipation fins 40B extend downward relative to the plane perpendicular to the inclined surface portion 52bB, so that the angle between the horizontal surface portion 52bA of the first housing 52 and the front end surfaces 40Ba of the plurality of heat dissipation fins 40B can be increased, thereby ensuring a space S larger than the space S'. Therefore, heat accumulation in this space S can be made less likely, thereby improving the heat dissipation function of the image generation unit 20.

[0078] Thus, according to this embodiment, in the image projection device 10 configured to display the display image PIC on the image display section 102A by sequentially reflecting the light emitted from the image generation unit 20 by the first and second reflecting mirrors 70, 80, the heat dissipation function of the image generation unit 20 can be improved.

[0079] In particular, in the heat sink 40 of this embodiment, the front end faces 40Ba of the multiple heat dissipation fins 40B are formed to extend vertically, so that a space S with a wide included angle can be secured between the horizontal surface portion 52bA of the first housing 52 and the front end faces 40Ba of the multiple heat dissipation fins 40B. Furthermore, the multiple heat dissipation fins 40B can be formed with a larger volume to increase their heat capacity within a range that allows them to be easily inserted into the multiple fin insertion holes 52c, thereby improving their heat dissipation function.

[0080] Furthermore, the lower wall portion 52b of the first housing 52 is formed so that the angle of inclination of the connection region 52b1 that connects the horizontal surface portion 52bA located below the second reflecting mirror 80 and the inclined surface portion 52bB gradually changes, which makes it easy to form a larger space S between the horizontal surface portion 52bA of the first housing 52 and the front end surface 40Ba of the plurality of heat dissipation fins 40B. This makes it even more difficult for heat to accumulate in the space S, and also makes it easier for convection to occur along the lower surface of the lower wall portion 52b in the space below the first housing 52 (see the arrows in FIG. 5A), thereby further improving the heat dissipation function of the image generation unit 20.

[0081] In this case, the heat sink 40 is also formed so that the front region 40Aa of its main body 40A extends along the connection region 52b1 of the first housing 52, thereby improving the positioning accuracy of the heat sink 40 relative to the first housing 52 and enhancing the heat dissipation function of the image generating unit 20.

[0082] Furthermore, in the heat sink 40 of this embodiment, the rear end surfaces 40Bb of the multiple heat dissipation fins 40B are also formed so as to extend downward relative to the surface perpendicular to the inclined surface portion 52bB. Therefore, the multiple heat dissipation fins 40B can be formed with a larger volume and have a larger heat capacity within a range in which they can be easily inserted into the multiple fin insertion holes 52c, thereby improving their heat dissipation function.

[0083] Furthermore, in the heat sink 40 of this embodiment, the lower end surfaces 40Bc of the multiple heat dissipation fins 40B are formed so as to extend along a horizontal plane, so that the amount of downward protrusion of the multiple heat dissipation fins 40B can be minimized while maximizing their thermal capacity.

[0084] In the above embodiment, the front end surface 40Ba and the rear end surface 40Bb of the heat dissipation fins 40B are described as extending along a vertical plane, but they may be configured to extend in a direction inclined relative to the vertical plane. Also, in the above embodiment, the bottom end surface 40Bc of the heat dissipation fins 40B are described as extending along a horizontal plane, but they may be configured to extend in a direction inclined relative to the horizontal plane.

[0085] 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.

[0086] 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.

[0087] Next, a modification of the above embodiment will be described.

[0088] First, a first modification of the above embodiment will be described.

[0089] FIG. 6 is a diagram similar to FIG. 4, showing the main part of an image projection device according to this modified example.

[0090] The basic configuration of this modified example is the same as that of the above embodiment, but the configuration of the first housing 152 is partially different from that of the above embodiment.

[0091] That is, in this modification, the image generating unit 20 is supported by the inclined surface 152bB of the lower wall 152b of the first housing 152 via the heat sink 40, and the heat sink 40 has a configuration in which a plurality of heat dissipation fins 40B extending downward from its main body 40A are inserted into fin insertion holes 152c formed in the inclined surface 152bB. However, this modification differs from the above embodiment in that the fin insertion hole 152c is configured as a single opening. Specifically, this fin insertion hole 152c has a horizontally elongated rectangular opening shape.

[0092] Even when the configuration of this modified example is adopted, the same effects as those of the above embodiment can be obtained.

[0093] Next, a second modification of the above embodiment will be described.

[0094] FIG. 7 is a diagram similar to FIG. 1, showing an image projection device 210 according to this modified example.

[0095] As shown in FIG. 7, the basic configuration of this modified example is the same as that of the above embodiment, but the configurations of the first and second reflecting mirrors 270, 280 are different from those of the above embodiment, and therefore the configurations of the first housing 252 of the housing 250 and the heat sink 240 are partially different from those of the above embodiment.

[0096] That is, the image projection device 210 according to this modified example is also configured to display the display image PIC on the image display section 102A by sequentially reflecting the light emitted from the image generating unit 20 by the first and second reflecting mirrors 270, 280, but the first reflecting mirror 270 is configured to converge the light emitted from the image generating unit 20 further rearward of the device than the second reflecting mirror 280 in the vertical direction.

[0097] To achieve this, the reflecting surfaces 270a and 280a of the first and second reflecting mirrors 270 and 280 have a surface shape with a larger curvature in the up-down direction than in the above embodiment.

[0098] In this modification, the image generating unit 20 is also disposed below the midpoint between the first and second reflecting mirrors 270, 280, but its position is displaced upward compared to the above embodiment.

[0099] Furthermore, in this modification, the image generation unit 20 is also supported by the inclined surface portion 252bB of the lower wall portion 252b of the first housing 252 via the heat sink 240. In this case, as in the above embodiment, the heat sink 240 is formed so that its front end surface 240Ba extends downward relative to the plane perpendicular to the inclined surface portion 252bB, with the plurality of heat dissipation fins 240B inserted into the plurality of fin insertion holes 252c formed in the inclined surface portion 252bB.

[0100] In this modified example, the lower wall portion 252b of the first housing 252 does not have a connection region 52b1 as in the above embodiment, and the main body portion 240A of the heat sink 240 does not have a front region 40Aa as in the above embodiment.

[0101] Even when the configuration of this modified example is adopted, substantially the same effects as those in the above embodiment can be obtained.

[0102] Furthermore, by adopting the configuration of this modified example, it becomes possible to position the image generation unit 20 at a higher position than in the above embodiment, within a range that does not block the reflected light traveling from the first reflector 270 to the second reflector 280, thereby making it possible to configure the housing 250 even more compactly.

[0103] 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.

[0104] Furthermore, the present invention is not limited to the configurations described in the above embodiment and its modified examples, and various other modified configurations can be adopted.

[0105] This international application claims priority based on Japanese Patent Application No. 2023-137016, filed on August 25, 2023, the entire contents of which are incorporated herein by reference.

[0106] The above descriptions of specific embodiments of the present invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications and variations will be apparent to those skilled in the art in light of the above description.

[0107] 2 Driver 10, 210 Image projection device 12 Internal space 20 Image generation unit 22 Liquid crystal panel 30 Optical unit 32 Light emitting element 34 Substrate 36 Lens 38 Lens holder 40, 240 Heat sink 40A, 240A Main body 40Aa Front region 40B, 240B Heat dissipation fin 40Ba Front end surface 40Bb, 240Ba Rear end surface 40Bc Bottom end surface 50, 250 Housing 52, 152, 252 First housing 52a Peripheral wall 52b, 152b, 252b Bottom wall 52bA Horizontal surface 52bB, 152bB, 252bB Inclined surface 52bC Reverse inclined surface 52b1 Connection region 52c, 152c, 252c Fin insertion hole 54 Second housing 54a Opening 54b Outer peripheral flange 54c Light-shielding piece 60 Light-transmitting cover 70, 270 First reflector 70a, 80a, 270a, 280a Reflecting surface 80, 280 Second reflector 80b Flange 82 Actuator 100 Vehicle 102 Front window 102A Image display unit 104 Steering wheel Ax Axis PIC Display image R Optical path S Space

Claims

1. An image projection device configured to project a display image on an image display section, comprising: an image generating unit which generates the display image; first and second reflecting mirrors which sequentially reflect light emitted from the image generating unit towards the image display section; and a housing which contains the image generating unit and the first and second reflecting mirrors; the first reflecting mirror is disposed rearward of the device from the second reflecting mirror; the image generating unit is supported via a heat sink on a lower wall of the housing in a state where it is disposed between the first and second reflecting mirrors and lower than the first and second reflecting mirrors; the lower wall of the housing is configured as an inclined surface portion with an area below a midpoint between the first and second reflecting mirrors inclined downward towards the rear of the device; the heat sink comprises a main body which supports the image generating unit, and a plurality of heat dissipation fins which are formed to extend downward from the main body in the front-rear direction of the device, and is disposed with the plurality of heat dissipation fins inserted into fin insertion holes formed in the inclined surface portion; The image projection device, wherein the heat sink is formed such that front end surfaces of the plurality of heat dissipation fins extend in a downward direction relative to a plane perpendicular to the inclined surface portion.

2. The image projection device as described in claim 1, characterized in that the lower wall portion of the housing has a horizontal surface portion in the area located below the second reflector, and the inclination angle of the connection area connecting the horizontal surface portion and the inclined surface portion is formed so as to gradually change.

3. The image projection device according to claim 2, wherein said heat sink is formed so that a front region of said main body portion extends along said connection region.

4. An image projection device as claimed in claim 1 or 2, characterized in that the heat sink is formed so that rear end faces of the plurality of heat dissipation fins extend in a downward direction relative to the plane perpendicular to the inclined surface portion.

5. The image projection device according to claim 1 or 2, wherein said heat sink is formed so that lower end faces of said plurality of heat dissipating fins extend along a horizontal plane.

6. An image projection device as described in claim 1 or 2, characterized in that the first reflecting mirror is configured to converge the light emitted from the image generating unit on the rear side of the device relative to the second reflecting mirror in the vertical direction.

Images