Image display apparatus

Abstract

To provide an image display device capable of efficiently radiating heat and miniaturizing the device.SOLUTION: The image display device 1 includes a display unit 2 that emits display light L, and a reflective optical part 3 that reflects the display light L and projects the display light L on a display member 103, the display unit 2 includes a metal circuit board 4 in which a plate-shaped metal member 42 is laminated in a thickness direction and a light emitting element 41 is mounted, and a display part 5 that receives light emitted from the light emitting element 41 and emits the display light L, the metal circuit board 4 includes an arrangement region 45 in which the light emitting element 41 is arranged and a non-arrangement region 46 in which the light emitting element 41 is not arranged, the non-arrangement region 46 is configured to be provided at a position higher than the arrangement region 45 in the vertical direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, as an image display device, there is known an image display device that includes a display unit (display), a plurality of light sources that illuminate the display, and a circuit board on which the plurality of light sources are mounted, as described in Patent Document 1. This image display device dissipates heat by attaching heat dissipation means having a plurality of heat sinks formed on the circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-165624 Summary of the Invention [Problem to be solved by the invention]

[0004] The image display device described in Patent Document 1 above requires space for installing heat dissipation means, and there is room for improvement in that it is difficult to reduce the size of the device.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image display device that can efficiently dissipate heat and can be made smaller in size. [Means for solving the problem]

[0006] That is, the image display device of the present invention comprises a display unit that emits display light and a reflective optical section that reflects the display light and projects it onto a display member, the display unit having a metal circuit board on which light-emitting elements are mounted by stacking plate-shaped metal members in the thickness direction, and a display section that receives light emitted from the light-emitting elements and emits the display light, the metal circuit board having an arrangement area where the light-emitting elements are arranged and a non-arrangement area where the light-emitting elements are not arranged, and the non-arrangement area is configured to be located at a higher position in the vertical direction than the arrangement area. [Effects of the Invention]

[0007] According to the image display device of the present invention, heat can be efficiently dissipated and the device can be made smaller. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an image display device according to an embodiment. [Figure 2] FIG. 2 is a perspective view of a display unit of the image display device according to the embodiment. [Figure 3] FIG. 3 is an exploded perspective view of a display unit of the image display device according to the embodiment. [Figure 4] FIG. 4 is a perspective view showing an outline of a metal circuit board of the image display device according to the embodiment. [Figure 5] FIG. 5 is a side view of the metal circuit board of the image display device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same.

[0010] [Embodiment] This embodiment relates to an image display device. In the following description, of a first direction, a second direction, and a third direction that intersect with one another, the first direction is referred to as the "front-rear direction X," the second direction is referred to as the "vehicle width direction Y," and the third direction is referred to as the "height direction Z." Here, the front-rear direction X, the vehicle width direction Y, and the height direction Z are perpendicular to one another. The front-rear direction X corresponds to the front-rear direction of a vehicle on which the image display device is mounted. The vehicle width direction Y corresponds to the vehicle width direction of a vehicle on which the image display device is mounted. The vehicle width direction Y and the height direction Z correspond to intersecting directions that intersect with the front-rear direction X. Unless otherwise specified, each direction used in the following description represents a direction when each part is mounted on a vehicle. Note that orthogonal here includes nearly perpendicular.

[0011] As shown in FIG. 1, the image display device 1 is a device installed in a vehicle 100 and displays an image, and is, for example, a head-up display device that projects display light L onto a display member 103 of the vehicle 100 to display a virtual image S. The image display device 1 projects the display light L onto the display member 103 in the vehicle 100, causing the driver of the vehicle 100 to recognize a virtual image S in front of the eye point EP. The display member 103 is, for example, a windshield. The image display device 1 is disposed below the display member 103, and is installed, for example, in an instrument panel provided on the dashboard. The eye point EP is assumed in advance to be the driver's viewpoint.

[0012] The image display device 1 includes a display unit 2 and a reflective optical unit 3. The display unit 2 and the reflective optical unit 3 are housed in or installed in a housing 11, and emit display light L from an opening 12 toward a display member 103.

[0013] The reflective optical unit 3 is an optical system unit that reflects the display light L and guides it toward the display member 103, and is configured, for example, by a mirror 31. The mirror 31 reflects the display light L emitted from the display unit 2 and projects the display light L onto the display member 103 through the opening 12. The mirror 31 has, for example, a concave reflective surface, which can enlarge an image. The shape of the reflective surface may be, for example, a free-form surface, which can correct distortion and aberration of the image. While FIG. 1 shows a case where the reflective optical unit 3 is configured by one mirror 31, the reflective optical unit 3 may be configured by multiple mirrors and reflect the display light L multiple times.

[0014] As shown in FIGS. 2 and 3 , the display unit 2 generates and outputs display light L and includes a metal circuit board 4, a display unit 5, and wiring members 6. For example, the display unit 2 is configured by attaching a cover 21 to the metal circuit board 4, and sequentially arranging a condenser lens 22, a light distribution lens 23, a case 24, a frame member 25, a sheet member 26, a sheet member 27, and the display unit 5 between the metal circuit board 4 and the cover 21. In the drawings, the depth direction of the display unit 2 is referred to as the "unit longitudinal direction D1," the width direction is referred to as the "unit width direction D2," and the height direction is referred to as the "unit height direction D3." The unit longitudinal direction D1, the unit width direction D2, and the unit height direction D3 are perpendicular to one another. The unit longitudinal direction D1 is typically a direction along the emission direction of the display light L or a direction along the thickness direction of the metal circuit board 4, and when installed in the vehicle 100, it is a direction that obliquely intersects the longitudinal direction X shown in FIG. 1 . The unit width direction D2 is typically a direction along the vehicle width direction Y shown in FIG.

[0015] The metal circuit board 4 is a circuit board on which light-emitting elements 41 are mounted, and is a component that constitutes a backlight. For example, the metal circuit board 4 has a plate-shaped metal member 42, and the light-emitting elements 41 are mounted on the metal member 42 via an insulating layer. The metal member 42 is laminated in the thickness direction of the metal circuit board 4, and is formed to have the same size as the main surface 40 of the metal circuit board 4. Here, the term "same size" includes approximately the same size. For example, a plate material whose main component is aluminum is used as the metal member 42. Examples of plates whose main component is aluminum include aluminum plate material and aluminum alloy plate material.

[0016] The main surface 40 of the metal circuit board 4 is the surface of the plate-shaped metal circuit board 4, and is a surface formed in a direction intersecting the thickness direction. The thickness direction is a direction along the unit front-rear direction D1. The light-emitting elements 41 are light sources that emit light to serve as backlight, and a plurality of light-emitting elements 41 are arranged on the main surface 40 of the metal circuit board 4. For example, LEDs (Light Emitting Diodes) are used as the light-emitting elements 41. For example, chip components are used and surface-mounted. The light-emitting elements 41 may be components that have lead wires and are insert-mounted, or may be light-emitting components other than LEDs.

[0017] The cover 21 is a box-shaped component with an opening on the surface facing the metal circuit board 4, and is attached to, for example, the main surface 40 of the metal circuit board 4 and fixed with screws 28. An exit window 211 is formed in the cover 21, allowing the display light L to be emitted. In addition, flange portions 212 are formed on both ends of the cover 21 in the unit width direction D2, allowing the cover 21 to be fixed to the housing 11 or a member attached to the housing 11.

[0018] The condensing lens 22 is a lens that condenses light emitted from the light-emitting elements 41 and is made of a light-transmitting member. The condensing lens 22 has a plurality of lens portions 221 corresponding to the plurality of light-emitting elements 41, and condenses light emitted from each light-emitting element 41 using the respective lens portions 221. Each lens portion 221 has a flat incident surface and a convexly curved exit surface, and is formed facing the light-emitting element 41. By providing a lens portion 221 for each of the plurality of light-emitting elements 41 in this manner, the light distribution angle or illumination angle of light emitted from the light-emitting element 41 can be set small, and the distance between the condensing lens 22 and the light distributing lens 23 can be shortened. Therefore, the image display device 1 according to this embodiment can configure a thin backlight unit including the light-emitting elements 41, the condensing lens 22, and the light distributing lens 23.

[0019] The light distributing lens 23 is a lens that adjusts the traveling direction of the light emitted from the condensing lens 22 to a predetermined direction, and is made of a light-transmitting member. The light distributing lens 23 is disposed opposite the condensing lens 22.

[0020] The case 24 is provided so as to cover the condensing lens 22 and the light distributing lens 23 between it and the metal circuit board 4. For example, the case 24 is attached integrally with the metal circuit board 4, the condensing lens 22, the light distributing lens 23, and the cover 21 by screws 28. In other words, the screws 28 are inserted sequentially through the metal circuit board 4, the condensing lens 22, the light distributing lens 23, and the case 24, and are screwed into the cover 21. An opening 241 is formed in the case 24, and the opening 241 is capable of guiding light emitted from the light distributing lens 23 along the unit front-rear direction D1.

[0021] Between the case 24 and the cover 21, there are provided a frame material 25, a sheet material 26, a sheet material 27, and a display unit 5. The sheet materials 26 and 27 are optical sheets, and for example, a diffusion sheet, a light-collecting sheet, or the like is used.

[0022] The display unit 5 is disposed opposite the light emitting element 41 and emits display light L. The display unit 5 is a device that emits display light L by transmitting light that has been emitted from the light emitting element 41 and optically processed. For example, a light-transmitting TFT liquid crystal (Thin Film Transistor Liquid Crystal Display) is used as the display unit 5.

[0023] A wiring member 6 is connected to the display unit 5. The wiring member 6 is a wiring material for controlling the display unit 5, and electrically connects the display unit 5 and the metal circuit board 4. The wiring member 6 is made of a planar circuit board, and for example, a flexible printed circuit board is used. The wiring member 6 extends from the connection position with the display unit 5 to the outside of the cover 21 along the unit front-rear direction D1 and is connected to the metal circuit board 4. In other words, the wiring member 6 is connected to a connector 43 mounted on the metal circuit board 4.

[0024] As shown in Fig. 4, the metal circuit board 4 is formed in the shape of a rectangular plate, and has light-emitting elements 41 mounted on a main surface 40. A plurality of light-emitting elements 41 are mounted and arranged in an array along the unit width direction D2 and the unit height direction D3. For example, five light-emitting elements 41 are arranged along the unit width direction D2 and three light-emitting elements 41 are arranged along the unit height direction D3, for a total of 15 light-emitting elements 41. Note that the number and arrangement of the light-emitting elements 41 are not limited to those shown in Fig. 4.

[0025] The metal circuit board 4 has an arrangement area 45 and a non-arrangement area 46. The non-arrangement area 46 is located at a higher position on the metal circuit board 4 than the arrangement area 45 in the vertical direction. In FIG. 4 , the vertical direction is along the height direction Z, which is inclined with respect to the unit height direction D3. The metal circuit board 4 is located in a direction that intersects with the horizontal direction. That is, the metal circuit board 4 is located so that the normal direction of the main surface 40 intersects with the vertical direction. The normal direction of the main surface 40 is the unit front-rear direction D1, and the vertical direction is the height direction Z. The non-arrangement area 46 can be located at a higher position than the arrangement area 45 as long as the metal circuit board 4 is not located so that the normal direction of the main surface 40 is the vertical direction. In other words, when the metal circuit board 4 is arranged so that the main surface 40 is perpendicular to the vertical direction, the non-placement area 46 and the placement area 45 are at the same height in the vertical direction, but when the metal circuit board 4 is arranged so that the main surface 40 is not perpendicular to the vertical direction, the non-placement area 46 can be located at a higher position than the placement area 45.

[0026] The arrangement region 45 is a region on the main surface 40 of the metal circuit board 4 where the light emitting element 41 is arranged. The non-arrangement region 46 is a region on the main surface 40 of the metal circuit board 4 other than the arrangement region 45. For example, the arrangement region 45 is a region on the main surface 40 of the metal circuit board 4 below an upper end position 47 of the light emitting element 41 that is arranged at the top in the unit height direction D3. The non-arrangement region 46 is a region on the main surface 40 of the metal circuit board 4 above the upper end position 47. In other words, the light emitting element 41 is mounted on the metal circuit board 4 with its position biased downward. For example, the non-arrangement region 46 is set to be larger than the arrangement region 45.

[0027] The metal circuit board 4 is mounted with a connector 43 connected to the wiring member 6, together with the light-emitting element 41. The connector 43 is not a heat-generating component, and therefore it is conceivable to mount it on, for example, a circuit board that does not have the metal member 42. However, in the image display device 1 according to this embodiment, by mounting the connector 43 on the metal circuit board 4, the metal circuit board 4 can be made large. The connector 43 is placed, for example, in a non-placement area 46 of the metal circuit board 4.

[0028] The connector 43 is mounted on the metal circuit board 4 at a position higher in the vertical direction than the light emitting element 41. For example, the connector 43 is provided in the non-placement area 46 of the metal circuit board 4, and is mounted at a position higher than the light emitting element 41 provided in the placement area 45. Therefore, the heat H emitted from the light emitting element 41 is efficiently transferred to the connector 43 side.

[0029] A light emission control connector 44 is mounted on the metal circuit board 4. The light emission control connector 44 is a connector for connecting wiring material (not shown) for controlling the light emission of the light emitting element 41. The wiring material for light emission control is connected to, for example, an external device of the image display device 1. Note that in FIG. 4, the connector 43 and the light emission control connector 44 are shown in outline.

[0030] Next, the heat dissipation function of the image display device 1 according to this embodiment will be described.

[0031] 2, when the image display device 1 is operated, a control signal is input to the display unit 5 through the wiring member 6, and the display unit 5 generates an image in accordance with the control signal. Also, in Fig. 3, an operation signal is input to the light-emitting element 41, and the light-emitting element 41 emits light. The light emitted from the light-emitting element 41 is optically processed by the condenser lens 22, the light distribution lens 23, the sheet material 26, and the sheet material 27, and is then incident on the display unit 5.

[0032] 1, display light L is output from the display unit 5. The display light L is reflected by the reflecting optical unit 3, emitted from the opening 12, and projected onto the display member 103. The driver of the vehicle 100 can recognize the display light L projected onto the display member 103 as a virtual image S.

[0033] In FIG. 5 , as the image display device 1 operates, the light-emitting element 41 mounted on the metal circuit board 4 emits light and generates heat. The heat generated by the light-emitting element 41 is conducted to the metal member 42 and dissipated through the metal member 42. Here, the metal member 42 is stacked in the thickness direction (unit front-rear direction D1) of the metal circuit board 4 and is provided continuously from the arrangement region 45 where the light-emitting element 41 is mounted to the non-arrangement region 46 where the connector 43 is mounted. Therefore, the heat H generated by the light-emitting element 41 moves through the metal member 42 in the unit width direction D2 and the unit height direction D3, and is conducted to the connector 43 side and diffused over a wide area. That is, the heat H is conducted from the arrangement region 45 to the non-arrangement region 46 and dissipated within the arrangement region 45 and the non-arrangement region 46. Therefore, the image display device 1 according to this embodiment has higher heat dissipation efficiency than when heat is dissipated only in the arrangement region 45 of the metal circuit board 4. Therefore, the image display device 1 of this embodiment can achieve a predetermined heat dissipation effect without installing multiple heat dissipation fins or the like on the metal member 42, so the components that make up the backlight can be made thinner, and the display unit 2 and the image display device 1 can be made smaller.

[0034] 5, the metal circuit board 4 has a non-arrangement area 46 located at a higher position than the arrangement area 45. Therefore, heat H generated by the light-emitting element 41 moves smoothly from the arrangement area 45 to the non-arrangement area 46 through the metal member 42 and is diffused. Therefore, the image display device 1 according to this embodiment can efficiently dissipate the heat H generated from the light-emitting element 41 by the metal circuit board 4, thereby improving heat dissipation. As a result, the image display device 1 according to this embodiment can sufficiently dissipate heat even without providing heat dissipation fins on the metal circuit board 4, allowing the components constituting the backlight to be made thinner and the display unit 2 and the image display device 1 to be made smaller.

[0035] As described above, in the image display device 1 according to this embodiment, the non-arrangement area 46 is provided at a higher position than the arrangement area 45 on the metal circuit board 4, and therefore the heat generated by the light emitting element 41 can be smoothly transferred and diffused from the arrangement area 45 to the non-arrangement area 46 through the metal member 42. This allows the image display device 1 according to this embodiment to improve the heat dissipation performance of the metal circuit board 4. Therefore, the image display device 1 according to this embodiment can be made smaller by omitting the installation of heat dissipation fins and the like.

[0036] Furthermore, in the image display device 1 according to this embodiment, the metal circuit board 4 is provided in a direction intersecting the horizontal direction, so that the non-placement area 46 can be provided at a higher position than the placement area 45. Therefore, the image display device 1 according to this embodiment can improve the heat dissipation performance of the metal circuit board 4.

[0037] In the image display device 1 according to this embodiment, by mounting the light emitting elements 41 and the connector 43 on the metal circuit board 4, the metal circuit board 4 can be made larger and the heat dissipation properties of the metal circuit board 4 can be improved compared to when an intermediate board for mounting the connector 43 is provided separately from the metal circuit board 4. Therefore, the image display device 1 according to this embodiment can be made smaller by omitting the installation of heat dissipation fins and the like.

[0038] Furthermore, in the image display device 1 according to this embodiment, the connector 43 is mounted at a higher vertical position on the metal circuit board 4 than the light-emitting element 41, so that the heat H emitted from the light-emitting element 41 can be efficiently transferred to the connector 43 side, thereby improving the heat dissipation performance of the metal circuit board 4.

[0039] Although the image display device according to the present embodiment has been described, the image display device according to the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. The image display device according to the present embodiment may be configured by appropriately combining the components of the embodiments and modified examples described above. [Explanation of symbols]

[0040] 1: Image display device 2: Display unit 3: Reflective optics section 4: Metal circuit board 5: Display section 41: Light-emitting element 42: Metal parts 45: Placement area 46: Non-placement area 103: Display member L:Display light

Claims

1. a display unit that emits display light; a reflection optical unit that reflects the display light and projects it onto a display member, the display unit includes a metal circuit board formed by laminating plate-shaped metal members in a thickness direction and mounting light-emitting elements thereon, and a display section that receives light emitted from the light-emitting elements and emits the display light; the metal circuit board has an arrangement region in which the light-emitting element is arranged and an absence region in which the light-emitting element is not arranged, The non-placement area is provided at a position higher than the placement area in the vertical direction. Image display device.

2. The metal circuit board is provided in a direction intersecting the horizontal direction. The image display device according to claim 1 .

Images