Image irradiation device

Abstract

To enhance a heat radiation function of an image generation unit in an image irradiation device configured to display a display image on an image display section by sequentially reflecting emission light from the image generation unit by first and second reflectors.SOLUTION: In a lower wall section 52b of a first housing 52, a region positioned below an intermediate position of first and second reflectors 70, 80 is configured as an inclined surface section 52bB inclined to a lower side toward a device rear side. An image generation unit 20 is supported by the inclined surface section 52bB through a heat sink 40. At the time, as the heat sink 40, a plurality of heat radiation fins 40B extending from a lower surface of a body section 40A are inserted into a plurality of fin insertion holes 52c formed in the lower wall section 52b. Each front end face 40Ba of the plurality of heat radiation fins 40B is formed to extend in a downward direction with respect to a direction perpendicular to the inclined surface section 52bB.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[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 on the inside of the vehicle cabin when placed inside the vehicle cabin.

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

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

[0005] [Patent Document 1] Patent Publication No. 2021-162704 Summary of the Invention [Problem to be solved by the invention]

[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 in 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 arrange the image generating unit diagonally upward 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 configure a part 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 to insert 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, so a narrow wedge-shaped space is formed between the area of ​​the lower wall of the housing that is located on the front side of the device and the front end surfaces of the multiple heat dissipation fins, and heat accumulates in this space. This reduces the heat dissipation function of the image generating unit.

[0009] It should be noted that such a problem may 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 section by sequentially reflecting light emitted from an image generation unit by first and second reflecting mirrors. [Means for solving the problem]

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

[0012] That is, the image projection device according to the present invention is In an image projection device configured to project a display image on an image display unit, the display device includes an image generating unit that generates an image for display, first and second reflecting mirrors that sequentially reflect light emitted from the image generating unit toward the image display section, and a housing that accommodates the image generating unit and the first and second reflecting mirrors, the first reflecting mirror is disposed on the rear side of the device relative to the second reflecting mirror, the image generating unit is disposed between the first reflecting mirror and the second reflecting mirror and below the first and second reflecting mirrors, and is supported by a lower wall portion of the housing via a heat sink; a lower wall portion of the housing is configured as an inclined surface portion 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 includes 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 a front-rear direction of the device, and is arranged in a state in which the plurality of heat dissipation fins are inserted into fin insertion holes formed in the inclined surface portion, The heat sink is characterized in that the front end faces of the plurality of heat dissipating fins are formed to extend in a downward direction relative to a plane 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 project a display image, and for example, a translucent plate arranged on the front window of the vehicle or on the inside of the passenger compartment can be used.

[0015] The above-mentioned "first and second reflecting mirrors" are not particularly limited in their specific arrangement or reflective surface shape, so long as the first reflecting mirror is positioned rearward of the device relative to the second reflecting mirror and 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] As long as the front end surfaces of the "plurality of heat dissipating fins" are formed to extend in a downward direction relative to the plane perpendicular to the inclined surface portion, the specific direction is not particularly limited. Effect of the Invention

[0018] The image projection device of the present invention is configured to project a display image on the image display section by sequentially reflecting the light emitted from the image generating unit by the first and second reflecting mirrors. The image generating unit is supported on the lower wall section 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 section, 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 enabling the housing to be configured compactly.

[0020] Furthermore, since the heat sink of the present invention is formed so that the front end faces of the multiple heat dissipation fins extend in a downward direction relative to the plane perpendicular to the inclined surface portion, 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 and the front end faces of the multiple heat dissipation fins, and heat will accumulate in this space, reducing the heat dissipation function of the image generation unit.

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

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

[0024] In the above configuration, if the lower wall of the housing has a region located below the second reflector configured as a horizontal surface portion, and the angle of inclination of the connection region connecting the horizontal surface portion and the inclined surface portion is gradually changed, it is possible to easily form a larger space between the region located on the front side of the device on the lower wall of the housing and the front end surfaces of the multiple heat dissipation fins. This makes it even more difficult for heat to accumulate in the space, and makes it easier for convection to occur along the lower surface of the lower wall portion in the space below the housing, thereby further improving the heat dissipation function of the image generating 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 while also improving the heat dissipation function of the image generating unit.

[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 in a downward direction 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, it becomes possible to position the image generating unit 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. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a side cross-sectional view showing an image projection device according to an embodiment of the present invention mounted on a vehicle. [Diagram 2] View from the direction of arrow II in Figure 1 [Diagram 3] Detailed view of part III in Fig. 1 [Figure 4] Cross-sectional view of line IV-IV in Figure 3 [Diagram 5] 4(a) is an enlarged view of the main part of FIG. 3, and (b) is a view similar to (a) showing a comparative example of the above embodiment. [Figure 6] FIG. 5 is a view similar to FIG. 4, showing a first modified example of the embodiment. [Figure 7] FIG. 2 is a view similar to FIG. 1, showing a second modified example of the embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 in a state where it is mounted on a vehicle 100. Fig. 2 is a view seen in the direction of the arrow II in Fig. 1.

[0032] 1 and 2, the direction indicated by X is the "forward" of the image projection device 10 (also the "forward" of the vehicle), the direction indicated by Y is the "leftward" direction perpendicular to the "forward", and the direction indicated by Z is the "upward" direction. This is the same in other figures besides FIG. 1 and 2.

[0033] As shown in FIGS. 1 and 2, the image projection device 10 of 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 when the driver 2 visually recognizes the display image PIC projected on the image display unit 102A by the image projection device 10. As shown in FIG.

[0035] 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 is set as a horizontally elongated rectangular region. This allows the driver 2 of the vehicle 100 to easily visually recognize the display image PIC projected on the image display unit 102A.

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

[0037] The image projection device 10 is disposed so as to be located 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 window 102, a housing 50 that accommodates these, and a translucent 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 portion 54b, and is assembled to the first housing 52 with the outer peripheral flange portion 54b in contact with an upper end opening of the peripheral wall portion 52a of the first housing 52. The second housing 54 is formed with an opening 54a for transmitting the reflected light from the second reflecting mirror 80 toward the image display unit 102A.

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

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

[0044] The first reflecting mirror 70 is disposed in a rear region of the internal space 12, and the second reflecting mirror 80 is disposed in a front region of the internal 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 behind the image generating unit 20, and is configured to reflect the light emitted from the image generating unit 20 forward. The reflecting surface 70a of the first reflecting mirror 70 has an outer shape of a horizontally elongated rectangle when viewed from the front of the device, and its horizontal cross-sectional shape is configured as a convex curve, and its vertical cross-sectional shape 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 and 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 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 70a of the first reflecting mirror 70.

[0048] First reflecting mirror 70 is fixedly supported by 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 flanges 80b formed so as to protrude from both left and right ends toward the rear side of the reflecting surface 80a, and one of the flanges 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 reflected light 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 a heat sink 40 .

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

[0052] In addition, the area of ​​the lower wall portion 52b of the first housing 52 located in front of the lamp from the inclined surface portion 52bB is configured as a horizontal surface portion 52bA extending along an approximately horizontal plane, and the area located behind the lamp from the inclined surface portion 52bB is configured as an inverted inclined surface portion 52bC 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 inclination angle gradually changes in a connection region 52b1 that connects the horizontal surface portion 52bA and the inclined surface portion 52bB. Specifically, the connection region 52b1 is formed so as to extend along a convex cylindrical surface extending in the left-right direction.

[0054] The image generating unit 20 includes a liquid crystal panel 22 and an optical unit 30 configured to illuminate the liquid crystal panel 22 from its rear side with a 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 circumferential flange portion is supported by the lens holder 38. The substrate 34 is supported on its underside by the heat sink 40, in a state in which the substrate 34 is disposed 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 in which the liquid crystal panel 22 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 portion 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, while its front region 40Aa is formed so as to extend curvedly along the connection region 52b1 of the first housing 52.

[0062] The heat dissipating fins 40B are formed so as to extend in the front-rear direction of the device along a vertical plane at equal intervals from the bottom surface of the main body 40A. At this time, the heat dissipating fins 40B are formed so that their front end faces 40Ba and rear end faces 40Bb extend downward relative to the surface perpendicular direction of the inclined surface portion 52bB. Specifically, the front end face 40Ba and rear end face 40Bb are both formed so as to extend along a vertical plane perpendicular to the front-rear direction of the device. In addition, the heat dissipating fins 40B are formed so that their bottom end faces 40Bc 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 is elongated in the front-rear direction of the device in a plan view. Each fin insertion hole 52c is formed with a left-right width slightly wider than the plate thickness of each heat dissipation fin 40B and a front-rear width slightly wider than the front-rear width of each heat dissipation fin 40B, and its front end surface and rear end surface are formed to extend along a vertical plane.

[0064] The heat sink 40 is positioned with respect to the first housing 52 by inserting the multiple heat dissipation fins 40B into the multiple fin insertion holes 52c from above, whereby the lower surface of the main body portion 40A is placed in surface contact with the upper surface of the inclined surface portion 52bB. At this time, the front region 40Aa of the main body portion 40A of the heat sink 40 and the connection region 52b1 of the lower wall portion 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 project a 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 70, 80. The image generating 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 reflecting mirrors 70, 80, and the heat sink 40 is arranged with a plurality of heat dissipation fins 40B inserted into a plurality of fin insertion holes 52c formed in the lower wall portion 52b, thereby making it easy to ensure the heat dissipation function of the image generating 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 reflecting mirrors 70, 80, is configured as an inclined surface portion 52bB that slopes downward toward the rear of the device, so that the image generating unit 20 can be easily positioned diagonally upward toward the rear of the device so that its emitted light is incident on the first reflecting mirror 70, thereby enabling the housing 50 to be configured compactly.

[0068] In addition, in the heat sink 40 of this embodiment, the front end faces 40Ba of the multiple heat dissipation fins 40B are formed to extend downward with respect to the plane perpendicular direction of the inclined surface portion 52bB, so that the following advantageous effects can be obtained. This point will be described with reference to FIG. 5.

[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 this embodiment in that the configuration of the first housing 52' is partially different, 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 this 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 the present embodiment, but there is no connection region 52b1 between the two, in which the inclination angle gradually changes as in the present embodiment.

[0072] Similarly to the heat sink 40 of the present 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 flat along the upper surface of the inclined surface portion 52bB' of the first housing 52', but a front region 40Aa like that of the heat sink 40 of the present 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 in a rectangular shape from the main body 40A' diagonally downward toward the front (specifically, in the direction perpendicular to the surface of the inclined surface 52bB'). The plurality of heat dissipation fins 40B' are inserted from the diagonally upward rear side into the plurality of fin insertion holes 52c' formed in the inclined surface 52bB' of the first housing 52'.

[0075] For this reason, the front end faces 40Ba' of the heat dissipating fins 40B' extend in a direction perpendicular to the inclined surface portion 52bB', which results in the formation of a narrow wedge-shaped space S' between the horizontal surface portion 52bA' of the first housing 52' and the front end faces 40Ba' of the heat dissipating fins 40B'. Since heat accumulates in this space S', the heat dissipation function of the image generating unit 20 is reduced.

[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 in the vertical direction and their rear end faces extend diagonally upward.

[0077] 5(a), in the heat sink 40 of this embodiment, the front end faces 40Ba of the plurality of heat dissipation fins 40B extend downward relative to the surface perpendicular direction of the inclined surface portion 52bB, so that the angle between the horizontal surface portion 52bA of the first housing 52 and the front end faces 40Ba of the plurality of heat dissipation fins 40B can be increased, thereby ensuring a space S larger than the space S'. Therefore, it is possible to make it difficult for heat to accumulate in this space S, thereby improving the heat dissipation function of the image generating unit 20.

[0078] Thus, according to this embodiment, in an image projection device 10 configured to project a display image PIC on an image display section 102A by sequentially reflecting light emitted from an image generating unit 20 by the first and second reflecting mirrors 70, 80, the heat dissipation function of the image generating 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 in the vertical direction, so that a space S having 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. Also, within a range where the multiple heat dissipation fins 40B can be easily inserted into the multiple fin insertion holes 52c, the multiple heat dissipation fins 40B can be formed with a larger volume to increase the heat capacity, thereby improving the heat dissipation function.

[0080] Moreover, the lower wall portion 52b of the first housing 52 is formed so that the inclination angle of the connection region 52b1 connecting the horizontal surface portion 52bA located below the second reflecting mirror 80 and the inclined surface portion 52bB gradually changes, so that it is possible to easily form a larger space S between the horizontal surface portion 52bA of the first housing 52 and the front end surface 40Ba of the multiple 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 arrow in FIG. 5(a)), thereby further improving the heat dissipation function of the image generating 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 faces 40Bb of the multiple heat dissipation fins 40B are also formed to extend in a downward direction relative to the plane perpendicular to the inclined surface portion 52bB, so that 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 the 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 dissipating 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 dissipating 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 vehicle 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 a main part of an image projection device according to this modified example.

[0090] The basic configuration of this modification is similar to 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 on 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, but differs from the above embodiment in that the fin insertion hole 152c is configured as a single opening. Specifically, the 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 similar to that of the above embodiment, but the configurations of the first and second reflectors 270, 280 are different from those of the above embodiment, and therefore the configurations of the first housing 252 and the heat sink 240 of the housing 250 are partially different from those of the above embodiment.

[0096] That is, the image projection device 210 of this modified example is also configured to project 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 on the rear side of the device relative to the second reflecting mirror 280 in the vertical direction.

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

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

[0099] Furthermore, in this modified example, the image generating unit 20 is also supported on 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 such that its front end surface 240Ba extends downward with respect to the surface perpendicular direction of the inclined surface portion 252bB with a plurality of heat dissipation fins 240B inserted into a 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 of 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 make the housing 250 even more compact.

[0103] It should be noted that the numerical values ​​given 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. [Explanation of symbols]

[0105] 2 Driver 10, 210 Image projection device 12 Interior Space 20 Image Generation Unit 22 Liquid crystal panel 30 Optical Unit 32 Light emitting element 34 Substrate 36 Lenses 38 Lens holder 40, 240 Heat sink 40A, 240A Main unit 40Aa Anterior area 40B, 240B Heat sink fin 40Ba front end surface 40Bb, 240Ba rear end surface 40Bc Bottom end surface 50, 250 Housing 52, 152, 252 1st Housing 52a Peripheral wall part 52b, 152b, 252b Lower wall part 52bA Horizontal part 52bB, 152bB, 252bB Slope section 52bC Reverse slope section 52b1 Connection area 52c, 152c, 252c Fin insertion hole 54 Second Housing 54a opening 54b Outer periphery flange 54c Light shielding piece 60 Translucent cover 70, 270 1st reflector 70a, 80a, 270a, 280a reflective surface 80, 280 2nd reflector 80b Flange part 82 Actuator 100 vehicles 102 Front window 102A Image display section 104 Steering Wheel Ax axis PIC Display image R optical path S space

Claims

1. In an image projection device configured to project a display image on an image display unit, the display device includes an image generating unit that generates an image for display, first and second reflecting mirrors that sequentially reflect light emitted from the image generating unit toward the image display section, and a housing that accommodates the image generating unit and the first and second reflecting mirrors, the first reflecting mirror is disposed on the rear side of the device relative to the second reflecting mirror, the image generating unit is disposed between the first reflecting mirror and the second reflecting mirror and below the first and second reflecting mirrors, and is supported by a lower wall portion of the housing via a heat sink; a lower wall portion of the housing is configured as an inclined surface portion 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 includes 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 a front-rear direction of the device, and is arranged in a state in which the plurality of heat dissipation fins are 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 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 gradually changed.

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

4. 3. The image projection device according to claim 1, wherein the heat sink is formed such that rear end faces of the plurality of heat dissipation fins extend in a downward direction relative to a plane perpendicular to the inclined surface portion.

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

6. 3. The image projection device according to claim 1, wherein the first reflecting mirror is configured to converge the light emitted from the image generating unit on a rear side of the device relative to the second reflecting mirror in the vertical direction.

Images