Vehicle display device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NIPPON SEIKI CO LTD
- Filing Date
- 2026-01-27
- Publication Date
- 2026-08-06
Smart Images
Figure JP2026002546_06082026_PF_FP_ABST
Abstract
Description
Vehicle display device
[0001] The present invention relates to an improved technology for a vehicle display device that displays a virtual image on the windshield of a vehicle by display light emitted from a display.
[0002] Conventionally, various vehicle display devices (in-vehicle projection display devices) that project display light onto the windshield of a vehicle and display a virtual image have been proposed. Such a vehicle display device is disposed within the instrument panel of a vehicle and mounts electronic components with a large heat generation amount, so heat dissipation measures are taken. For example, a technique of forcibly cooling by providing a cooling fan and passing cooling air through the housing is disclosed in Patent Document 1.
[0003] The vehicle display device disclosed in Patent Document 1 includes a display unit, a circuit board that controls this display unit, a case that houses this circuit board, a flow path through which cooling air for cooling the display unit and the circuit board flows, and a fan that generates cooling air. This vehicle display device is arranged such that the display unit faces the upper side of the vehicle. Inside the case, a circuit board housing portion and the flow path that are separated from each other in the longitudinal direction and the vehicle width direction of the vehicle are provided.
[0004] The display unit has a liquid crystal display panel and an LED (backlight) that illuminates this liquid crystal display panel, and is provided on the front surface of the front plate of the case. The circuit board controls the display unit and each fan, and includes an IC chip (corresponding to a driver IC) that controls the display unit. This IC chip is provided on the back surface of the circuit board. The circuit board and the IC chip are arranged in the circuit board housing portion and are covered with a board cover for blocking external noise. Further, the circuit board is provided on the back surface of the front plate of the case. The heat of the highly heat-generating IC chip is transmitted to the board cover via a substrate-side heat conduction member. The heat of this board cover is transmitted to the back cover of the case via a cover-side heat conduction member. Since the circuit board housing portion that houses the IC chip and the flow path through which cooling air flows are separated, the IC chip can be isolated from the cooling air to enhance electrical insulation.
[0005] International Publication No. 2023 / 048292
[0006] However, in the vehicle display device disclosed in Patent Document 1, the circuit board becomes larger in the longitudinal direction of the vehicle when the number of components mounted on the circuit board increases. Consequently, if the vehicle display device itself is to maintain its longitudinal direction in the vehicle, the flow path becomes narrower. Alternatively, if the flow path is to be maintained, the vehicle display device itself becomes larger in the longitudinal direction. Therefore, it is disadvantageous to place the vehicle display device in the narrow space within the instrument panel of a vehicle.
[0007] The present invention was made to solve the above problems, and aims to provide a technology that can miniaturize vehicle display devices while ensuring a cooling effect for heat-generating components.
[0008] The vehicle display device comprises: a display panel for displaying images; a plurality of light sources used for transmitted illumination of the display panel; a first substrate having a first surface and a first back surface opposite to the first surface, on which the plurality of light sources are mounted; a second substrate having a second surface facing the first back surface of the first substrate with a gap between them, and a second back surface opposite to the second surface, on which circuit components are mounted; a fan for generating cooling air to cool the first substrate and the second substrate; and a heat dissipation member interposed between the first back surface of the first substrate and the second surface of the second substrate, having fins that form a flow path for the cooling air and dissipating heat transferred from the first substrate into the cooling air, wherein the second substrate is placed on the fins.
[0009] According to the present invention, it is possible to provide a vehicle display device that can isolate the heat-generating driver IC from the cooling air and enhance the cooling effect of the driver IC.
[0010] This is a schematic diagram of a vehicle equipped with a vehicle display device according to Embodiment 1. Figure 2A is a perspective view of the vehicle display device shown in Figure 1 as seen from the driver's side, and Figure 2B is a perspective view taken along arrow 2B in Figure 2A (a perspective view seen from the front of the vehicle). This is a cross-sectional view along line 3-3 in Figure 2B. This is a cross-sectional view along line 4-4 in Figure 3. This is a cross-sectional view along line 5-5 in Figure 3. This is a top view. This is a perspective view of the vehicle display device shown in Figure 3, seen from below, with the closing plate and lower cover omitted. This is a cross-sectional view of the area around the board-to-board connector shown in Figure 3. This is a cross-sectional view along line 8-8 in Figure 3. This is a cross-sectional view of the vehicle display device according to Embodiment 2. This is a cross-sectional view along line 10-10 in Figure 9. This is a cross-sectional view along line 11-11 in Figure 9. This is an enlarged view of part 12 in Figure 10. Figure 13A is a first modified diagram showing a configuration in which the driver IC and peripheral components shown in Figure 12 are housed in one recess of the heat dissipation member, and Figure 13B is a second modified diagram showing a configuration in which the driver IC and peripheral components shown in Figure 13A are housed separately in two recesses of the heat dissipation member. This is a modified diagram of the second substrate of the vehicle display device according to Embodiment 3. This is a cross-sectional view of the vehicle display device according to Embodiment 4. This is a cross-section along line 16-16 in Figure 15, showing the area around the substrate-to-substrate connector.
[0011] Embodiments of the present invention will be described below with reference to the accompanying drawings. The best embodiments described below are provided for ease of understanding the present invention. Therefore, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.
[0012] In the explanation, left and right refer to the left and right relative to the vehicle's driver, and front and rear refer to the front and rear relative to the vehicle's direction of travel. Also, in the diagram, Fr indicates front, Rr indicates rear, Le indicates left from the driver's perspective, Ri indicates right from the driver's perspective, Up indicates up, and Dn indicates down.
[0013] <Example 1> The vehicle display device 20 of Example 1 will be described with reference to Figures 1 to 8.
[0014] Figure 1 shows a vehicle 10 equipped with the vehicle display device 20 of Embodiment 1. The vehicle 10, such as a passenger car, has an instrument panel 12 at the front of the passenger compartment 11. The vehicle display device 20 is installed inside the instrument panel 12. This vehicle display device 20 is configured as an on-board projection display device that projects display light Ld onto the windshield 13 of the vehicle 10 to display a virtual image Vi. The display light Ld projected from the vehicle display device 20 is displayed as an image on the windshield 13. The driver can see the virtual image Vi along with the background in front of the vehicle 10.
[0015] Figure 2A shows the configuration of the vehicle display device 20 as seen from the driver's side, and Figure 2B shows the configuration of the vehicle display device 20 as seen from the front of the vehicle 10 (see Figure 1). The cooling air outlet 84 (cooling air outlet 84) faces forward of the vehicle 10 (arrow Fr direction). Note that the cooling air outlet 84 is not limited to facing forward of the vehicle 10, and can also be configured to face, for example, backward or downward.
[0016] As shown in Figures 3 and 4, the vehicle display device 20 includes a display panel 21, a plurality of light sources 22 used for transmitted illumination of the display panel 21, a controller 23 that controls the display panel 21 and the plurality of light sources 22, a driver IC 24 that drives the plurality of light sources 22 by a control signal from the controller 23, peripheral components 25 electrically connected to the driver IC 24, and a first substrate 30 and a second substrate 40 arranged in parallel to each other. These light sources 22, controller 23, driver IC 24, and peripheral components 25 are so-called circuit components.
[0017] The display panel 21 displays a display light Ld (image) that can be projected onto the windshield 13 (see Figure 1), and is composed of, for example, a TFT-type liquid crystal display panel.
[0018] The multiple light sources 22 are backlights for the display panel 21, and are configured, for example, with LEDs arranged relative to the display panel 21. Since multiple light sources 22 are grouped together, the overall heat generation is high.
[0019] The controller 23 controls the display panel 21 and multiple light sources 22 based on information acquired from the control unit 14 (external control unit 14) on the vehicle 10 side. The controller 23 generates a lot of heat.
[0020] The driver IC 24 drives multiple light sources 22 (LEDs 22) according to the control signals of the controller 23, and is composed of a semiconductor integrated circuit for stably emitting light from the LEDs 22. This driver IC 24 generates a lot of heat.
[0021] The peripheral components 25 of the driver IC 24 are external electrical components necessary for the driver IC 24 to operate and are electrically connected to the driver IC 24. Examples of these peripheral components 25 include capacitors and resistors.
[0022] The first substrate 30 (first printed circuit board 30) is a long member in the vehicle width direction and has a first surface 31 facing the display panel 21 side and a first back surface 32 on the opposite side of the first surface 31. Referring also to Figure 5, a plurality of light sources 22, a driver IC 24, and peripheral components 25 are mounted on the first surface 31 of the first substrate 30. Here, the area AL1 on the first substrate 30 where the plurality of light sources 22 are arranged is called the "light source arrangement area AL1," and the area AL2 which is biased to one side (for example, to the right) in the vehicle width direction relative to the light source arrangement area AL1 is called the "electronic component arrangement area AL2." The driver IC 24 and peripheral components 25 are located biased towards the electronic component arrangement area AL2 on the first surface 31. Since the first substrate 30 mounts a plurality of light sources 22 that form a backlight, it is sometimes called a backlight substrate 30.
[0023] As shown in Figures 3 and 6, the second substrate 40 (second printed circuit board 40) is a member that is elongated in the vehicle width direction and has a second surface 41 that faces the first back surface 32 of the first substrate 30 with a gap Di (see Figure 4), and a second back surface 42 on the opposite side of the second surface 41. The size of the gap Di is set to an appropriate size considering the cooling effect of the cooling air. The second surface 41 is parallel (including substantially parallel) to the first substrate 30.
[0024] Furthermore, the second substrate 40 is provided only on the side of the first substrate 30, which is long in the vehicle width direction, that has the driver IC 24 and peripheral components 25 located on (approximately half of the total length). A flat closing plate 45 is provided on the portion of the first substrate 30 corresponding to the remaining half.
[0025] The closing plate 45 is aligned with the second surface 41 of the second substrate 40 and is parallel (including substantially parallel) to the first substrate 30. The surface 45a of the closing plate 45 faces the first back surface 32 of the first substrate 30 with a gap Di between them and is flush with the second surface 41 of the second substrate 40. The back surface 45b of the closing plate 45 is flush with the second back surface 42 of the second substrate 40. If this closing plate 45 is not provided, a portion equivalent to a flat closing plate may be formed by making the inside of the lower cover 92 (described later) protrude toward the first substrate 30 (heat dissipation member 80, described later).
[0026] As shown in Figure 6, the second back surface 42 of the second circuit board 40 is equipped with a controller 23, a power connector 51, a real vehicle video signal input connector 52, a display panel connection connector 53, and a power supply circuit 54. The second circuit board 40 is sometimes called the controller board 40 because it is equipped with the controller 23.
[0027] See also Figure 1. The power connector 51 can be connected to the power cable 15a of the external power supply 15 installed on the vehicle 10 side. The vehicle video signal input connector 52 can be connected to the control signal line 14a of the control unit 14 (external control unit 14) installed on the vehicle 10 side. This external control unit 14 acquires, for example, vehicle speed, engine speed, various vehicle information, navigation information, etc. from the vehicle 10's ECU via various sensors. The display panel connection connector 53 can be connected to the display panel 21, and the display control signal line 55 that transmits the control signals of the controller 23 to the display panel 21 is connected to it. The power supply circuit 54 generates the required output power from the input power obtained from the external power supply 15 and supplies it to the controller 23 and driver IC 24, and is sometimes called a power conversion circuit.
[0028] Here, the display panel connector 53 will be explained in more detail. As shown in Figure 4, a display panel substrate 56 is provided on the side of the heat dissipation member 80, which will be described later. This display panel substrate 56 is equipped with display panel terminals 57 and a display panel driver 58. The display panel terminals 57 are connected to the display panel connector 53 by a display control signal line 55. The display panel driver 58 drives the display panel 21 (liquid crystal panel 21) by a control signal from the controller 23 and is composed of a semiconductor integrated circuit for stable display of the display panel 21.
[0029] As shown in Figures 7 and 8, the first substrate 30 and the second substrate 40 are electrically connected by a substrate-to-substrate connector 60 (BtoB connector 60). This substrate-to-substrate connector 60 is located in one corner (for example, towards the right) of the vehicle width direction within the electronic component placement area AL2 of the first substrate 30.
[0030] This board-to-board connector 60 consists of a first connector 61 mounted on the first back surface 32 of the first board 30, and a second connector 62 that is detachable from the first connector 61 and mounted on the second front surface 41 of the second board 40. The connection method of the board-to-board connector 60 is a parallel connection method that connects the boards 30 and 40 in parallel. The first and second connectors 61 and 62 are straight-type connectors that extend perpendicularly to the surfaces of the boards 30 and 40. By fitting the first and second connectors 61 and 62 perpendicularly to the surfaces of the boards 30 and 40, the boards 30 and 40 are integrated. Therefore, the distance Di between the boards 30 and 40 is maintained by the board-to-board connector 60, and the boards 30 and 40 are less likely to separate from each other by the board-to-board connector 60.
[0031] The second connector 62 on the second substrate 40 is lighter than the first connector 61 on the first substrate 30. For example, the first connector 61 is made up of a male connector (plug connector), and the second connector 62 is made up of a lightweight female connector (receptacle connector).
[0032] As shown in Figures 3, 4, and 8, a fan 70 and a heat dissipation member 80 are provided between the first substrate 30 and the second substrate 40.
[0033] The fan 70 generates cooling air to cool the first substrate 30 and the second substrate 40. It is positioned to draw in outside air from below and send it as cooling air between the first substrate 30 and the second substrate 40, and is configured as, for example, an axial flow fan. The fan 70 is located on one side of the first substrate 30 in the vehicle width direction (for example, slightly to the left in the vehicle width direction), that is, at the end on the side of the light source placement area AL1. The intake port 71 of the fan 70 faces downward, and the discharge port 72 of the fan 70 faces the other side in the vehicle width direction (for example, to the right in the vehicle width direction). The cooling air discharged from the discharge port 72 flows through the space between the first and second substrates 30 and 40, which are long in the vehicle width direction, to the opposite side from the fan 70, and is discharged from the cooling air outlet 84 of the heat dissipation member 80.
[0034] The heat dissipation member 80 (heat sink 80) is interposed between the first substrate 30 and the second substrate 40 and is made of a material having thermal conductivity and electrical conductivity, such as a metallic material such as magnesium alloy or aluminum. The cooling air outlet 84 described above is formed on the outer wall of this heat dissipation member 80.
[0035] The heat dissipation member 80 comprises a flat plate-shaped base 81 that overlaps the first back surface 32 of the first substrate 30, and a plurality of fins 82 that extend from the base 81 toward the second surface 41 of the second substrate 40.
[0036] The size of the base body 81 is set to be larger than the first substrate 30 in both the longitudinal and width directions of the vehicle. The base body 81 has a contact surface 81a that can contact the entire surface of the first back surface 32 of the first substrate 30, and a back surface 81b on the opposite side of the contact surface 81a. The contact surface 81a is preferably capable of efficiently transferring heat from the first back surface 32 of the first substrate 30, and is configured as a flat surface that can make uniform thermal contact with the first back surface 32. It is more preferable to increase the heat transfer efficiency from the first back surface 32 to the contact surface 81a by ensuring close contact between the first back surface 32 of the first substrate 30 and the contact surface 81a using a heat dissipation sheet or thermal paste (not shown). The fan 70 is provided, for example, on the back surface 81b of the base body 81.
[0037] As shown in Figure 7, the base body 81 of the heat dissipation member 80 has a passable portion 81c through which at least the first connector 61 can pass. This passable portion 81c is formed, for example, by a through hole or notch that penetrates the base body 81.
[0038] As shown in Figures 3, 4, and 8, the multiple fins 82 extend to the second surface 41 of the second substrate 40 (including the vicinity of the second surface 41), thereby forming a cooling airflow channel 83 between the first substrate 30 and the second substrate 40. This channel 83 is the space between adjacent fins 82, 82. On the upstream side of the channel 83, which is the fan 70 side, a closing plate 45 (or part of the lower cover 92) is positioned above the fins 82 so that it forms the lid of the channel 83, and on the downstream side, the second substrate 40 is positioned above the fins 82 so that it forms the lid of the channel 83. The channel 83 has a rectangular cross-section formed by the back surface 81b, the fins 82, the closing plate 45, and the second substrate 40. This allows heat transferred from the first substrate 30 and the second substrate 40 to be dissipated into the cooling air flowing through the channel 83.
[0039] The second substrate 40 is not positioned near the fan 70. In other words, the upstream side of the flow path 83 is positioned opposite the multiple light sources 22 on the first substrate 30, and the second substrate 40 is positioned downstream of the flow path 83. This allows the cooling air flowing through the flow path 83, which has not yet absorbed heat near the fan 70, to absorb only the heat from the first substrate 30, which tends to become relatively hot. Furthermore, circuit components such as the driver IC 24 and peripheral components 25 are not positioned on the second back surface 42 of the second substrate 40 facing the flow path 83, thereby reducing the resistance of the cooling air flowing through the flow path 83.
[0040] As shown in Figure 8, the multiple fins 82 extend from the vicinity of the discharge port 72 of the fan 70 toward the opposite side of the fan 70, and also extend to the cooling air outlet 84 while bypassing the board-to-board connector 60 so as not to interfere with it. In other words, the passable portion 81c of the board-to-board connector 60 and the heat dissipation member 80 is formed outside the flow path 83, avoiding the flow path 83. For example, the shape of the multiple fins 82 is approximately L-shaped in plan view, bypassing the board-to-board connector 60. Therefore, the cooling air outlet 84 is formed on the side of the heat dissipation member 80 (the front outer wall 82f of the vehicle 10) (see also Figure 2B). The inlet 83a of the flow path 83 is located near the discharge port 72 of the fan 70, between each of the fins 82, 82. The outlet 83b of the flow path 83 coincides with the cooling air outlet 84.
[0041] As shown in Figures 4 and 6, among the multiple fins 82, the fins 82f and 82r located on the front and rear edges 81d, 81d of the base body 81 are sometimes referred to as "outer fins 82f and 82r". These outer fins 82f and 82r also serve as vertical plate-shaped outer walls of the heat dissipation member 80. One of the outer fins 82f and 82r constitutes the front outer wall 82f of the heat dissipation member 80, and the other constitutes the rear outer wall 82r. The front outer wall 82f faces the front of the vehicle 10.
[0042] Between the tips 82ff, 82rf (end faces 82ff, 82rf on the side opposite to the base 81) of the outer fins 82f, 82r and the second surface 41 of the second substrate 40, and between the tips 82ff, 82rf of the outer fins 82f, 82r and the surface 45a of the closing plate 45, seal members 85, 85 are interposed. By means of the seal members 85, 85, it is possible to seal so that the cooling air does not flow outwards from the flow path 83. The flow path 83 of the cooling air is completely covered by the second surface 41 of the second substrate 40, the surface 45a of the closing plate 45, and the back surface 81b of the base 81 from the inlet 83a to the outlet 83b.
[0043] Since the seal members 85, 85 have conductivity, it is possible to electrically conduct between the second substrate 40 and each fin 82 of the heat radiating member 80.
[0044] As shown in FIGS. 3 and 4, the first substrate 30 is covered by the upper cover 91. For this reason, the display panel 21, and the plurality of light sources 22, driver ICs 24, and peripheral components 25 mounted on the first surface 31 of the first substrate 30 are covered by the upper cover 91 within a range that does not block the display light Ld (see FIG. 1) emitted by the display panel 21. The display panel 21 is attached to the upper cover 91.
[0045] The second substrate 40, the closing plate 45, and the heat radiating member 80 are covered by the lower cover 92. For this reason, the controller 23, the power supply connection connector 51, the in-vehicle video signal input connector 52, the display panel connection connector 53, and the power supply circuit 54 mounted on the second back surface 42 of the second substrate 40 are covered by the lower cover 92. Further, the fan 70 provided on the back surface 81b of the base 81 is also covered by the lower cover 92. The lower cover 92 has an inlet opening 92a communicating with the suction port 71 of the fan 70 and an outlet opening 92b (see FIG. 8) communicating with the cooling air outlet 84.
[0046] Next, while referring to FIGS. 3 and 8, the heat dissipation function of the vehicle display device 20 will be described. The cooling air generated by the fan 70 cools the first and second substrates 30 and 40 and the respective fins 82 while flowing through the flow path 83, and is then discharged from the cooling air outlet 84 to the atmosphere. The heat generated by the plurality of light sources 22, driver ICs 24, and peripheral components 25 mounted on the first surface 31 of the first substrate 30 is discharged from the first substrate 30 to the cooling air flowing through the flow path 83 via the base 81 of the heat dissipation member 80 and the respective fins 82. The heat generated by the controller 23, power supply connector 51, in-vehicle video signal input connector 52, display panel connection connector 53, and power supply circuit 54 mounted on the second back surface 42 of the second substrate 40 is discharged from the second substrate 40 to the cooling air flowing through the flow path 83 via the base 81 of the heat dissipation member 80 and the respective fins 82. Referring also to FIG. 4, the heat generated by the display panel driver 58 provided on the outer fin 82f is discharged from the outer fin 82f to the cooling air flowing through the flow path 83.
[0047] <Example 2> The vehicle display device 200 of Example 2 will be described while referring to FIGS. 9 to 12.
[0048] FIGS. 1, 2A, 2B, 6 to 8 are incorporated in Example 2 (shared with Example 1). FIG. 9 shows a cross-sectional configuration of the vehicle display device 200 and is represented corresponding to FIG. 3 above. FIG. 10 shows a cross-sectional configuration along line 10-10 of FIG. 9 and is represented corresponding to FIG. 4 above. FIG. 11 shows a cross-sectional configuration along line 11-11 of FIG. 9 and is represented corresponding to FIG. 5 above. FIG. 12 shows an enlarged view of a configuration in which the driver IC 24 is surrounded (accommodated) by the recess 210 of the heat dissipation member 80 shown in FIG. 11.
[0049] The vehicle display device 200 of Example 2 is characterized in that the driver IC 24 is mounted on the first back surface 32 of the first substrate 30 and is surrounded by the recess 210 of the heat dissipation member 80. Regarding other basic configurations, they are common to the vehicle display device 20 according to Example 1. For parts common to Example 1, the reference numerals are reused and detailed descriptions are omitted.
[0050] To describe Example 2 in detail, the peripheral components 25 are mounted on the first surface 31 of the first substrate 30, similar to Example 1. In contrast, the driver IC 24 is mounted on the first back surface 32 of the first substrate 30.
[0051] The heat dissipation member 80 has a recess 210 that is recessed from the contact surface 81a that can contact the first back surface 32 of the first substrate 30. This recess 210 (the inner wall surface 211 that forms the recess 210) can surround the driver IC 24. Therefore, the driver IC 24 is not exposed to the cooling air. The bottom surface 212 of this recess 210 (the inner bottom surface 212 that forms the recess 210) is configured as a surface that can thermally contact the driver IC 24, for example, a flat surface.
[0052] As shown in Figure 12, the driver IC 24 and the bottom surface 212 of the recess 210 are in close contact via a highly heat-conductive heat transfer layer 220, thereby increasing the heat transfer efficiency from the driver IC 24 to the bottom surface 212 compared to when an air layer is interposed. The heat transfer layer 220 is preferably composed of a highly heat-conductive heat dissipation sheet 221 or a thermal paste 222. In particular, since the thermal paste 222 is a viscous fluid substance, it is suitable for filling the uneven surface between the driver IC 24 and the bottom surface 212 of the recess 210 and conducting heat. The heat transfer layer 220 can also be interposed between the driver IC 24 and the inner wall surface 211 of the recess 210.
[0053] Next, the heat dissipation function of the vehicle display device 200 will be explained with reference to Figure 12. The heat generated by the driver IC 24 mounted on the first back surface 32 of the first substrate 30 is transferred from the first substrate 30 to the base 81 of the heat dissipation member 80. In addition, the heat generated by the driver IC 24 is transferred to the bottom surface 212 of the recess 210 either directly or via the heat transfer layer 220, and further transferred to the base 81 of the heat dissipation member 80. The heat transferred to the base 81 is released into the cooling air flowing through the channel 83 via each fin 82.
[0054] The vehicle display device 200 of Embodiment 2 described above also provides the same effects as the vehicle display device 20 of Embodiment 1.
[0055] The vehicle display device 200 of Embodiment 2 can be configured such that the driver IC 24 and peripheral components 25 are mounted on the first back surface 32 of the first substrate 30, as shown in the first modified example in Figure 13A and the second modified example in Figure 13B. In the first modified example in Figure 13A, both the driver IC 24 and the peripheral components 25 are surrounded by a single recess 210. In the second modified example in Figure 13B, the peripheral components 25 are surrounded by a recess 210A separate from the recess 210 surrounding the driver IC 24. Thus, the peripheral components 25 are surrounded by the recess 210 or another recess 210A that is recessed from the contact surface 81a. Other configurations are common to the vehicle display device 200 of Embodiment 2. For parts common to Embodiment 2, the same reference numerals are used and detailed explanations are omitted. The first and second modified examples described above also achieve the same effects as the vehicle display device 200 of Embodiment 2.
[0056] <Example 3> The vehicle display device 300 of Example 3 will be described with reference to Figure 14. Figure 14 shows the cross-sectional configuration of the vehicle display device 300 and is shown in correspondence with Figure 6 above. Other drawings are used in Example 3 (and are shared with Examples 1 and 2 and their modified examples 1 and 2).
[0057] The vehicle display device 300 of Example 3 is characterized by extending the second substrate 40 to the extent of the closing plate 45 (see Figure 3). Other basic configurations are common to the vehicle display devices 20, 200 of Examples 1 and 2 and their modified examples 1 and 2. For parts common to Examples 1 and 2 and their modified examples 1 and 2, the same reference numerals are used and detailed explanations are omitted.
[0058] To describe Example 3 in detail, the second surface 41 of the second substrate 40 completely covers the cooling air passage 83 from the inlet 83a to the outlet 83b. Therefore, the second surface 41 can dissipate heat over the entire length of the passage 83 from the inlet 83a to the outlet 83b.
[0059] The vehicle display device 300 of Embodiment 3 described above also provides the effects of the vehicle display devices 20 and 200 of Embodiments 1 and 2 and their modified versions 1 and 2.
[0060] <Example 4> The vehicle display device 400 of Example 4 will be described with reference to Figures 15 and 16. Figure 15 shows the cross-sectional configuration of the vehicle display device 400 and is shown in correspondence with Figure 14. Figure 16 shows the area around the board-to-board connector 60 in the cross-section along line 116-16 in Figure 15. Other drawings are used in Example 4 (shared with Examples 1, 2 and their modified examples 1-2, and Example 3).
[0061] The vehicle display device 400 of Example 4 is characterized by having a separate heat sink 410 interposed between the second substrate 40 and the heat dissipation member 80. Other basic configurations are common to the vehicle display devices 20, 200, and 300 of Example 1, Example 2 and its modifications 1-2, and Example 3. For parts common to Example 1, Example 2 and its modifications 1-2, and Example 3, the same reference numerals are used and detailed explanations are omitted.
[0062] To describe Example 4 in detail, the heat sink 410 is a flat plate-shaped member that is superimposed over the entire surface 41 of the second substrate 40. This heat sink 410 is made of a material that has thermal conductivity and electrical conductivity, and is made of a metallic material such as magnesium alloy or aluminum. The heat sink 410 has a passable portion 411 through which the second connector 62 can pass. This passable portion 411 is made of, for example, a through hole or notch that penetrates the heat sink 410.
[0063] The heat generated by the controller 23, power connector 51, vehicle video signal input connector 52, display panel connection connector 53, and power supply circuit 54, which are mounted on the second back surface 42 of the second circuit board 40, is released from the second circuit board 40 through the heat sink 410 into the cooling air flowing through the channel 83.
[0064] The vehicle display device 400 of Example 4 described above also provides the effects of the vehicle display devices 20, 200, and 300 of Examples 1, 2 and their modifications 1-2, and Example 3.
[0065] To summarize the effects of the above explanation, they are as follows:
[0066] The heat generated by the multiple light sources 22, which are high-heat-generating components, is efficiently dissipated from the substrate 30 to the cooling air flowing through the channel 83 via the heat dissipation member 80, while the driver IC 24, which tends to get hot, is placed on the surface 32 (first back surface 32) of the substrate 30 (first substrate 30) on the side facing the heat dissipation member 80. Furthermore, the driver IC 24 is surrounded by the recess 210 of the heat dissipation member 80, and the bottom surface 212 of this recess 210 is in thermal contact with the driver IC 24. The heat generated by the driver IC 24 is transferred to the heat dissipation member 80 via the substrate 30, and also directly to the heat dissipation member 80 from the bottom surface 212 of the recess 210, allowing it to be efficiently dissipated to the cooling air through the fins 82. Moreover, since the driver IC 24 is surrounded by the recess 210 of the heat dissipation member 80, it is not exposed to the cooling air.
[0067] This design allows the heat-generating driver IC 24 to be isolated from the cooling air, while also enhancing the cooling effect on the driver IC 24. As described above, both the heat emitted by the multiple light sources 22 and the heat emitted by the driver IC 24 can be efficiently cooled.
[0068] By ensuring close contact between the driver IC 24 and the bottom surface 212 of the recess 210 using a heat dissipation sheet 221 or thermal paste 222, the heat transfer efficiency from the driver IC 24 to the bottom surface 212 can be increased. As a result, the heat generated by the driver IC 24 can be dissipated more efficiently to the cooling air flowing through the channel 83 via the heat dissipation member 80.
[0069] The heat generated by the surrounding components 25 can also be efficiently dissipated to the cooling air flowing through the channel 83 via the heat dissipation member 80.
[0070] The heat generated by the peripheral components 25 of the driver IC 24 can also be efficiently cooled via the circuit board 30.
[0071] Since multiple light sources 22 that emit transmitted illumination light to the display panel 21 are grouped together, the overall heat generation is high. The controller 23 also generates a lot of heat. To address this, multiple light sources 22 are mounted on the first surface 31 of the first substrate 30, and the controller 23 is mounted on the second back surface 42 of the second substrate 40. A heat dissipation member 80 having fins 82 that form a cooling airflow channel 83 is interposed between the first back surface 32 of the first substrate 30 and the second surface 41 of the second substrate 40. By flowing cooling air between the first substrate 30 and the second substrate 40, both the multiple light sources 22 and the controller 23, which are high-heat generating components, can be efficiently cooled via the respective substrates 30 and 40.
[0072] Multiple light sources 22 and controllers 23, each being high-heat generating components, are arranged on the surfaces 31 and 42 (first surface 31 and second surface 42) of each substrate 30 and 40 that are opposite to the flow path 83. Since the controllers 23 are not located in the flow path 83, the distance (gap Di) between the first substrate 30 and the second substrate 40 can be narrowed accordingly.
[0073] The first substrate 30 and the second substrate 40 are connected to each other by an electrically connectable substrate-to-substrate connector 60. This ensures that the gap Di between each substrate 30 and 40 is reliably maintained, thereby securing the flow path. Furthermore, the substrates 30 and 40 are less likely to separate from each other due to the substrate-to-substrate connector 60. This reduces the number of fastening members such as screws used to assemble the substrates 30 and 40, improving the ease of assembly of each substrate 30 and 40. In addition, the contact surface 81a of the heat dissipation member 80, except for the passable portion 81c, can make uniform thermal contact with the first back surface 32 of the first substrate 30. This maximizes the area of thermal contact between the contact surface 81a and the first back surface 32. In this way, the ease of assembly of the vehicle display device 20 can be improved while increasing the area of thermal contact between the first substrate 30 and the heat dissipation member 80.
[0074] Since electrical components 23, 51-54, and 62 are mounted on both sides 41 and 42 (the second front surface 41 and the second back surface 42) of the second substrate 40, reflow processing is performed on both sides 41 and 42, i.e., a double-sided reflow process is carried out. A heavy power connector 51 is provided on the second back surface 42 of the second substrate 40. To address this, a second connector 62, which is lighter than the first connector 61, is provided on the second front surface 41 of the second substrate 40.
[0075] After mounting the second connector 62 on the second surface 41 of the second circuit board 40 and performing the first reflow, the second circuit board 40 is flipped over, and various electrical components 23, 51-54, such as the power connector 51, are mounted on the second back surface 42 and a second reflow is performed. At this time, because the second connector 62 is lightweight, the surface tension of the solder provides a holding force, so it does not fall off due to its own weight. Various electrical components 23, 51-54 and the second connector 62 can be stably mounted on both sides 41 and 42 of the second circuit board 40.
[0076] The second surface 41 of the second substrate 40 can dissipate heat over the entire length of the flow path 83, from the inlet 83a to the outlet 83b. By expanding the heat transfer surface of the second surface 41, heat can be efficiently dissipated from the second substrate 40 into the cooling air.
[0077] By sealing the space between the tips 82ff, 82r of the fins 82 (outer fins 82f, 82r) and the second surface 41 of the second substrate 40 with sealing members 85, 85, the space between the fins 82 (outer fins 82f, 82r) and the second surface 41 can be completely shielded. Moreover, the sealing members 85, 85 can prevent the second surface 41 of the second substrate 40 from being scratched by the tips 82ff, 82r of the fins 82 (outer fins 82f, 82r).
[0078] By using conductive sealing members 85, 85 to provide electrical conductivity from the second substrate 40 to the fins 82 of the heat dissipation member 80, the emission / immunity withstand capability (resistance to electromagnetic noise) can be improved.
[0079] Multiple light sources 22 and controllers 23, each substrate 30, 40, heat dissipation member 80, and flow path 83 overlap each other when viewed from the display panel 21 side, allowing all of these components 22, 23, 30, 40, 80 and flow path 83 to be arranged in the vertical direction (arrows Up, Dn direction) of the vehicle display devices 20, 200 to 400. Therefore, the vehicle display devices 20, 200 to 400 can be made compact in the front-to-rear direction (arrows Fr, Rr direction).
[0080] Therefore, it is possible to miniaturize the vehicle display devices 20, 200 to 400 in the front-rear direction of the vehicle 10 while ensuring a cooling effect to cool the high-heat generating components 22, 23 (light source 22 and controller 23).
[0081] By mounting the driver IC 24, a high-heat-generating component, on the first surface 31 of the first substrate 30, it is possible to prevent it from being exposed to the cooling air flowing through the channel 83. Moreover, the driver IC 24, a high-heat-generating component, can be efficiently cooled by the cooling air via the first substrate 30.
[0082] The size of the recess 210 only needs to be small enough to surround the driver IC 24. The contact surface area 81a of the heat dissipation member 80 can be made larger by the amount that the recess 210 can be reduced in size. As a result, heat can be dissipated more efficiently from the first substrate 30 to the cooling air flowing through the channel 83 via the contact surface 81a.
[0083] By using a part of the lower cover 92 instead of the closing plate 45, the number of parts can be reduced.
[0084] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the functions and effects of the present invention.
[0085] For example, the vehicle display device 20 was configured as an in-vehicle projection type display device that projects display light Ld onto the windshield 13 of the vehicle 10 and displays a virtual image Vi. However, it could also be an in-vehicle display device that illuminates the driver with display light Ld and is directly visible to the driver.
[0086] The vehicle display devices 20, 200 to 400 of the present invention are suitable for use in projection-type display systems mounted on vehicles.
[0087] 10 Vehicle 13 Windshield 14 Vehicle-side control unit (external control unit) 15 External power supply 20,200 Vehicle display device 21 Display panel 22 Light source 23 Controller 24 Driver IC 25 Peripheral components 30 First circuit board (board) 31 First front surface (board) 32 First back surface (board) 40 Second circuit board 41 Second front surface 42 Second back surface 45 Closure plate 51 Power connection connector 52 Real vehicle video signal input connector 53 Display panel connection connector 54 Power supply circuit 60 Board-to-board connector 61 First connector 62 Second connector 70 Fan 71 Suction port 72 Discharge port 80 Heat dissipation member 81 Base 81a Contact surface 81b Back surface 81c Passable portion 82 Fin 82f Outer fin 82ff Tip of outer fin 82r Outer fin 82rf Tip of outer fin 83 Flow path 83a Inlet 83b Outlet 84 Cooling air outlet 85 Sealing member 210 Recess 212 Bottom of recess 210A Other recess 220 Heat transfer layer 221 Heat dissipation sheet 222 Thermal paste Di Spacing
Claims
1. A vehicle display device comprising: a display panel for displaying an image; a plurality of light sources used for transmitted illumination of the display panel; a first substrate having a first surface and a first back surface opposite to the first surface, with the plurality of light sources mounted on the first surface; a second substrate having a second surface facing the first back surface of the first substrate with a gap between them, and a second back surface opposite to the second surface, with circuit components mounted on the second back surface; a fan for generating cooling air to cool the first substrate and the second substrate; and a heat dissipation member interposed between the first back surface of the first substrate and the second surface of the second substrate, having fins that form a flow path for the cooling air and dissipating heat transferred from the first substrate to the cooling air, wherein the second substrate is positioned on the fins.
2. The vehicle display device according to claim 1, wherein the second substrate is arranged on a plurality of fins so as to be a cover for the flow path, and the heat dissipation member dissipates the heat transferred from the second substrate to the cooling air.
3. The vehicle display device according to claim 1, wherein the second substrate does not have circuit components placed on the second surface facing the flow path.
4. The vehicle display device according to claim 1, wherein the upstream side of the flow path is positioned opposite the plurality of light sources on the first substrate, and the second substrate is positioned downstream of the flow path.
5. The vehicle display device according to claim 2, further comprising a lower cover that covers the second substrate and the heat dissipation member, wherein the second substrate becomes the lid on the downstream side of the flow path, and the lower cover has a portion that becomes the lid of the flow path on the upstream side of the flow path.
6. A vehicle display device according to claim 1, comprising a board-to-board connector electrically connectable between the first board and the second board, wherein the board-to-board connector comprises a first connector mounted on the first back surface of the first board and a second connector detachably attached to the first connector and mounted on the second surface of the second board, and the heat dissipation member has a passable portion through which the first connector can pass, and the passable portion is formed in a position avoiding the flow path.
7. The vehicle display device according to claim 1, wherein the display panel is capable of projecting the image onto the windshield of a vehicle.