Vehicle display device

Abstract

The present invention makes it possible to ensure a cooling effect for cooling heat generating components while reducing the size of a vehicle display device in the front-rear direction of a vehicle. A vehicle display device 20 includes: a plurality of light sources 22 used for transillumination of a display panel 21; a controller 23 for controlling the display panel 21 and the plurality of light sources 22; a first board 30 having a first surface 31 on which the plurality of light sources 22 are mounted; a second board 40 having a second surface 41 which faces a first rear surface 32 of the first board 30 with an interval therebetween and a second rear surface 42 on which the controller 23 is mounted; a fan 70 for generating cooling air for cooling each of the boards 30 and 40; and a heat dissipating member 80 having fins 82 interposed between the first rear surface 32 and the second surface 41 to form a flow path 83 for the cooling air. The heat dissipating member 80 dissipates heat transmitted from the boards 30 and 40 into the cooling air.

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 front glass 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 front glass 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 amount of heat generation, 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. In this vehicle display device, the display unit is arranged so as to face the upper side of the vehicle. Inside the case, a circuit board housing portion and the flow path, which 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 covered with a board cover. Further, the circuit board is provided on the back surface of the front plate of the case.

[0005] International Publication No. 2023 / 048292

[0006] However, in the vehicle display device disclosed in Patent Document 1, the circuit board housing portion where the circuit board and the IC chip are arranged and the flow path through which the cooling air flows are completely separated and located in the longitudinal direction of the vehicle, so that the size increases in the longitudinal direction of the vehicle accordingly. Therefore, it is disadvantageous in arranging the vehicle display device in the narrow space within the instrument panel of the vehicle.

[0007] The present invention was made to solve the above problems, and aims to provide a technology that can miniaturize a vehicle display device in the front-to-rear direction of the vehicle while ensuring a cooling effect for heat-generating components.

[0008] The vehicle display device in the first embodiment includes: a display panel that displays an image that can be projected onto the windshield of a vehicle; a plurality of light sources used for transmitted illumination of the display panel; a controller that controls the display panel and the plurality of light sources; 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 the controller is mounted; a fan that generates 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 and the second substrate into the cooling air.

[0009] A vehicle display device in a second embodiment which may be dependent on the first embodiment further includes a driver IC that drives the plurality of light sources by a control signal of the controller, and a board-to-board connector that can be electrically connected between the first board and the second board, wherein the driver IC is mounted on the first surface of the first board, the board-to-board connector is composed of a first connector mounted on the first back surface of the first board, and a second connector that is detachably attached to the first connector and mounted on the second surface of the second board, and the heat dissipation member has a contact surface that can thermally and uniformly contact the first back surface of the first board, and has a passable portion through which the first connector can pass.

[0010] In a vehicle display device in a third embodiment which may be dependent on the second embodiment, the second connector on the second substrate is lighter than the first connector on the first substrate, and in addition to the controller, the second back surface of the second substrate is equipped with a power connection connector that can be connected to an external power supply, a real vehicle video signal input connector that can be connected to a control unit on the vehicle side, a display panel connection connector that can be connected to the display panel, and a power supply circuit that supplies power to the controller and the driver IC.

[0011] A vehicle display device in a fourth embodiment which may be dependent on the first embodiment further includes a driver IC that drives the plurality of light sources in response to a control signal from the controller, and peripheral components electrically connected to the driver IC, wherein the driver IC and the peripheral components are mounted on the first back surface of the first substrate, and the heat dissipation member has a contact surface that can make thermally uniform contact with the first back surface of the first substrate, and at least one recess that is recessed from the contact surface and capable of surrounding the driver IC and the peripheral components, the recess having a bottom surface that can make thermal contact with the driver IC and the peripheral components.

[0012] A vehicle display device in a fifth embodiment which may be dependent on the first embodiment further includes a driver IC that drives the plurality of light sources in response to a control signal from the controller, and peripheral components electrically connected to the driver IC, wherein the peripheral components are mounted on the first surface of the first substrate, the driver IC is mounted on the first back surface of the first substrate, and the heat dissipation member has a contact surface that can make thermally uniform contact with the first back surface of the first substrate, and a recess that is recessed from the contact surface and can surround the driver IC, the recess has a bottom surface that can make thermal contact with the driver IC.

[0013] In a vehicle display device in a sixth embodiment which may depend on the fourth or fifth embodiment, the driver IC and the bottom surface of the recess are in close contact via a heat dissipation sheet or thermal paste.

[0014] In a vehicle display device in a seventh embodiment which may depend on the first embodiment, the second surface of the second substrate completely covers the cooling air passage from the inlet to the outlet.

[0015] In a vehicle display device in an eighth embodiment which may depend on the first embodiment, the fins extend from the heat dissipation member toward the second surface of the second substrate, and a sealing member is interposed between the tip of the fin and the second surface of the second substrate.

[0016] In a vehicle display device according to a ninth embodiment which may depend on the eighth embodiment, the sealing member is conductive.

[0017] According to the present invention, it is possible to provide a technology that can miniaturize a vehicle display device in the longitudinal direction of the vehicle while ensuring a cooling effect for cooling heat-generating components.

[0018] 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. Figure 2B is a view along arrow 2B in Figure 2A (a perspective view as 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 perspective view of the vehicle display device shown in Figure 3, as 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 a 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 example 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. Figure 13B is a second modified diagram showing a configuration in which the driver IC and peripheral components shown in Figure 13A are separately housed 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-sectional view along line 16-16 in Figure 15, showing the area around the substrate-to-substrate connector.

[0019] 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.

[0020] 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.

[0021] <Example 1> The vehicle display device 20 of Example 1 will be described with reference to Figures 1 to 8.

[0022] 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 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. 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 together with the background in front of the vehicle 10.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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. Specifically, the gap Di is set to a range of, for example, 3 mm or more and 20 mm or less, preferably 5 mm or more and 15 mm or less, and more preferably 7 mm or more and 12 mm or less. The second surface 41 is parallel (including substantially parallel) to the first substrate 30.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 in which the boards 30 and 40 are connected in parallel. The first and second connectors 61 and 62 are straight type configurations 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.

[0039] 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).

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] The size of the base 81 is set to be larger than that of the first substrate 30 in both the vehicle front-rear direction and the vehicle width direction. This base 81 has a contact surface 81a that can contact the entire first back surface 32 of the first substrate 30, and a back surface 81b on the opposite side of this contact surface 81a. The contact surface 81a is preferably configured such that heat can be transmitted from the first back surface 32 of the first substrate 30 as efficiently as possible, and is a flat surface that can contact the first back surface 32 thermally uniformly. It is more preferable that the space between the first back surface 32 of the first substrate 30 and the contact surface 81a is made close by a heat dissipation sheet or thermal paste (not shown) to enhance the heat transfer efficiency from the first back surface 32 to the contact surface 81a. The fan 70 is provided, for example, on the back surface 81b of the base 81.

[0045] As shown in FIG. 7, the base 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 by, for example, a through hole or notch passing through the base 81.

[0046] As shown in FIGS. 3, 4, and 8, the plurality of fins 82 extend to the second surface 41 of the second substrate 40 (including up to the vicinity of the second surface 41), thereby forming a cooling air flow path 83 between the first substrate 30 and the second substrate 40. This flow path 83 is the space between adjacent fins 82, 82. The heat transmitted from the first substrate 30 and the second substrate 40 can be dissipated to the cooling air flowing through the flow path 83.

[0047] As shown in FIG. 8, the plurality of fins 82 extend from the vicinity of the discharge port 72 of the fan 70 toward the side opposite to the fan 70, and extend to the cooling air outlet 84 while bypassing so as not to interfere with the board-to-board connector 60. For example, the shape of the plurality of fins 82 is a substantially L-shaped configuration in plan view that bypasses the board-to-board connector 60. Therefore, the cooling air outlet 84 is formed on the side surface of the heat dissipation member 80 (the outer wall 82f on the front side of the vehicle 10) (see also FIG. 2B). The inlet 83a of the flow path 83 is located in the vicinity of the discharge port 72 of the fan 70 among the spaces between the fins 82, 82. The outlet 83b of the flow path 83 coincides with the cooling air outlet 84.

[0048] As shown in FIGS. 4 and 6, among the plurality of fins 82, the fins 82f and 82r located at both front and rear edges 81d and 81d of the base 81 may be referred to as "outer fins 82f and 82r". These outer fins 82f and 82r also serve as the 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 side of the vehicle 10.

[0049] A seal member 85 is interposed between the tips 82ff and 82rf (end faces 82ff and 82rf on the side opposite to the base 81) of the outer fins 82f and 82r and the second surface 41 of the second substrate 40, and between the tips 82ff and 82rf of the outer fins 82f and 82r and the surface 45a of the closing plate 45. The seal member 85 can seal to prevent the cooling air from flowing 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.

[0050] Since the seal member 85 has conductivity, it is possible to electrically connect between the second substrate 40 and each fin 82 of the heat dissipation member 80.

[0051] As shown in FIGS. 3 and 4, the first substrate 30 is covered by the upper cover 91. Therefore, the display panel 21, the plurality of light sources 22, the driver IC 24, and the 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.

[0052] The second circuit board 40, the closing plate 45, and the heat dissipation member 80 are covered by the lower cover 92. Therefore, the controller 23, the power connection connector 51, the vehicle video signal input connector 52, the display panel connection connector 53, and the power supply circuit 54, which are mounted on the second back surface 42 of the second circuit board 40, are covered by the lower cover 92. In addition, the fan 70 provided on the back surface 81b of the base body 81 is also covered by the lower cover 92. The lower cover 92 has an inlet opening 92a that communicates with the intake port 71 of the fan 70 and an outlet opening 92b (see Figure 8) that communicates with the cooling air outlet 84.

[0053] Next, the heat dissipation function of the vehicle display device 20 will be described with reference to Figures 3 and 8. The cooling air generated by the fan 70 flows through the flow path 83, cooling the first and second substrates 30, 40 and each fin 82, before being released into the atmosphere from the cooling air outlet 84. The heat generated by the multiple light sources 22, driver IC 24, and peripheral components 25 mounted on the first surface 31 of the first substrate 30 is released from the first substrate 30 to the cooling air flowing through the flow path 83 via the base 81 and each fin 82 of the heat dissipation member 80. The heat generated by the controller 23, power connection connector 51, actual 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 released from the second substrate 40 to the cooling air flowing through the flow path 83 via the base 81 and each fin 82 of the heat dissipation member 80. As also shown in Figure 4, the heat generated by the display panel driver 58 located on the outer fin 82f is released from the outer fin 82f into the cooling air flowing through the channel 83.

[0054] <Example 2> The vehicle display device 200 of Example 2 will be described with reference to Figures 9 to 12.

[0055] Figures 1, 2A, 2B, and 6-8 are used in Example 2 (and are shared with Example 1). Figure 9 shows the cross-sectional configuration of the vehicle display device 200 and corresponds to Figure 3. Figure 10 shows the cross-sectional configuration along line 10-10 in Figure 9 and corresponds to Figure 4. Figure 11 shows the cross-sectional configuration along line 11-11 in Figure 9 and corresponds to Figure 5. Figure 12 shows an enlarged view of the configuration in which the driver IC 24 is surrounded (housed) by the recess 210 of the heat dissipation member 80 shown in Figure 11.

[0056] The vehicle display device 200 of Embodiment 2 is characterized in that the driver IC 24 is mounted on the first back surface 32 of the first substrate 30 and surrounded by the recess 210 of the heat dissipation member 80. Other basic configurations are the same as those of the vehicle display device 20 of Embodiment 1. For parts common with Embodiment 1, the same reference numerals are used and detailed explanations are omitted.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The vehicle display device 200 of Embodiment 2 described above also provides the same effects as the vehicle display device 20 of Embodiment 1.

[0062] 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.

[0063] <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).

[0064] 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.

[0065] 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.

[0066] 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.

[0067] <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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] To summarize the above explanation, it is as follows:

[0073] Refer to Figures 1, 3, 9, 14, and 15. The vehicle display devices 20, 200 to 400 include a display panel 21 that displays an image that can be projected onto the windshield 13 of a vehicle 10, 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 first substrate 30 having a first surface 31 and a first back surface 32 opposite to the first surface 31, on which the plurality of light sources 22 are mounted, and a first substrate 30 facing the first back surface 32 with a spacing Di. The second substrate 40 has a matching second surface 41 and a second back surface 42 opposite to the second surface 41, with a controller 23 mounted on the second back surface 42; a fan 70 generates cooling air to cool the first substrate 30 and the second substrate 40; and a heat dissipation member 80 (heat sink 80) is interposed between the first back surface 32 of the first substrate 30 and the second surface 41 of the second substrate 40, having fins 82 that form a cooling airflow path 83, and dissipating heat transferred from the first substrate 30 and the second substrate 40 into the cooling air.

[0074] 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 each substrate 30 and 40.

[0075] Furthermore, the multiple light sources 22 and controllers 23, which are high-heat generating components, are arranged on the surfaces 31 and 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 space between the first substrate 30 and the second substrate 40 can be narrowed accordingly. As a result, the multiple light sources 22 and controllers 23, each substrate 30 and 40, the heat dissipation member 80, and the 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 the 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-rear direction (arrows Fr, Rr direction) of the vehicle.

[0076] 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).

[0077] Refer to Figures 3, 7, 9, and 14-16. Furthermore, the vehicle display devices 20, 200-400 include a driver IC 24 that drives a plurality of light sources 22 by a control signal from a controller 23, and a board-to-board connector 60 that can be electrically connected between the first board 30 and the second board 40. The driver IC 24 is mounted on the first surface 31 of the first board 30. The 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 surface 41 of the second board 40. The heat dissipation member 80 has a contact surface 81a that can make thermally uniform contact with the first back surface 32 of the first board 30, and a passable portion 81c through which the first connector 61 can pass.

[0078] In this way, by mounting the driver IC 24, which is 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, which is a high-heat-generating component, can be efficiently cooled by the cooling air via the first substrate 30.

[0079] Furthermore, 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 (see Figure 4) between each substrate 30 and 40 is reliably maintained, thereby securing the flow path 83. Moreover, 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 of the contact surface 81a with respect to the first back surface 32.

[0080] Therefore, the assembly of the vehicle display devices 20, 200 to 400 can be improved while increasing the thermal contact area between the first substrate 30 and the heat dissipation member 80.

[0081] Refer to Figures 1, 6 and 14. In the vehicle display devices 20, 200 to 400, the second connector 62 on the second circuit board 40 is lighter than the first connector 61 on the first circuit board 30. On the second back surface 42 of the second circuit board 40, in addition to the controller 23, a power connection connector 51 that can be connected to an external power supply 15, a real vehicle video signal input connector 52 that can be connected to the control unit 14 (external control unit 14) on the vehicle 10 side, a display panel connection connector 53 that can be connected to the display panel 21, and a power supply circuit 54 that supplies power to the controller 23 and the driver IC 24 are mounted.

[0082] As described above, 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, so a reflow process 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.

[0083] 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.

[0084] Refer to Figures 9 to 12, Figure 13A, and Figure 13B. Furthermore, the vehicle display device 200 includes a driver IC 24 that drives a plurality of light sources 22 in response to a control signal from a controller 23, and peripheral components 25 electrically connected to the driver IC 24. The driver IC 24 and peripheral components 25 are mounted on the first back surface 32 of the first substrate 30. The heat dissipation member 80 has a contact surface 81a that can make thermally uniform contact with the first back surface 32 of the first substrate 30, and at least one recess 210, 210A that is recessed from the contact surface 81a and capable of surrounding the driver IC 24 and peripheral components 25. These recesses 210, 210A have a bottom surface 212 that can make thermal contact with the driver IC 24 and peripheral components 25.

[0085] The heat generated by the multiple light sources 22, which are high-heat generating components, is efficiently dissipated from the first 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 positioned on the side of the heat dissipation member 80. The recess 210 of the heat dissipation member 80 surrounds the driver IC 24 and the surrounding components 25, and the bottom surface 212 of the recess 210 brings the driver IC 24 and the surrounding components 25 into thermal contact. As a result, the heat generated by the driver IC 24 and the surrounding components 25 can also be efficiently dissipated to the cooling air flowing through the channel 83 via the heat dissipation member 80. Therefore, both the heat generated by the multiple light sources 22 and the heat generated by the driver IC 24 and the surrounding components 25 can be efficiently cooled. Moreover, since the driver IC 24 and the surrounding components 25 are surrounded by the recess 210 of the heat dissipation member 80, they are not exposed to the cooling air.

[0086] Refer to Figures 9 to 12. As an alternative example, the vehicle display device 200 includes a driver IC 24 that drives a plurality of light sources 22 in response to a control signal from a controller 23, and peripheral components 25 electrically connected to the driver IC 24. These peripheral components 25 are mounted on the first surface 31 of the first substrate 30. The driver IC 24 is mounted on the first back surface 32 of the first substrate 30. The heat dissipation member 80 has a contact surface 81a that can make thermally uniform contact with the first back surface 32 of the first substrate 30, and a recess 210 that is recessed from the contact surface 81a and can surround the driver IC 24. The recess 210 has a bottom surface 212 that can make thermal contact with the driver IC 24.

[0087] The heat generated by the multiple light sources 22, which are high-heat generating components, is efficiently dissipated from the first substrate 30 through the heat dissipation member 80 to the cooling air flowing through the channel 83. On the other hand, the driver IC 24, which tends to get hot, is placed on the side of the heat dissipation member 80. The recess 210 of the heat dissipation member 80 surrounds the driver IC 24, and the bottom surface 212 of the recess 210 is in thermal contact with the driver IC 24. As a result, the heat generated by the driver IC 24 can also be efficiently dissipated through the heat dissipation member 80 to the cooling air flowing through the channel 83. Therefore, both the heat generated by the multiple light sources 22 and the heat generated by the driver IC 24 and surrounding components 25 can be efficiently cooled. 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.

[0088] In addition, 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.

[0089] Refer to Figures 9 to 12, 13A, and 13B. In the vehicle display device 200, the driver IC 24 and the bottom surface 212 of the recess 210 are in close contact via a heat dissipation sheet 221 or thermal paste 222.

[0090] In this way, by ensuring close contact between the driver IC 24 and the bottom surface 212 of the recess 210 with 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.

[0091] Refer to Figures 8 and 14. In the vehicle display device 300, the second surface 41 of the second substrate 40 completely covers the cooling air passage 83 from the inlet 83a to the outlet 83b.

[0092] In this way, 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.

[0093] Refer to Figures 4, 6 and 10. In the vehicle display devices 20, 200 to 400, the fins 82 extend from the heat dissipation member 80 toward the second surface 41 of the second substrate 40. A sealing member 85 is interposed between the tips 82ff, 82rf of the fins 82 (outer fins 82f, 82r) and the second surface 41 of the second substrate 40.

[0094] In this way, 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 the sealing member 85, the space between the fins 82 (outer fins 82f, 82r) and the second surface 41 can be completely shielded. Moreover, the sealing member 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).

[0095] Refer to Figures 4, 6, and 10. In the vehicle display devices 20, 200-400, the sealing member 85 is conductive.

[0096] By using a conductive sealing member 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.

[0097] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the functions and effects of the present invention.

[0098] The vehicle display devices 20, 200 to 400 of the present invention are suitable for use in projection-type display systems mounted on vehicles.

[0099] 10 Vehicle 13 Windshield 14 Vehicle-side control unit (external control unit) 15 External power supply 20 Vehicle display device (Example 1) 21 Display panel 22 Light source 23 Controller 24 Driver IC 25 Peripheral components 30 First substrate (substrate) 31 First front surface (substrate) 32 First back surface (substrate) 40 Second substrate 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 200 Vehicle display device (Example 2) 210 Recess 212 Bottom surface of recess 210A Other recess 220 Heat transfer layer 221 Heat dissipation sheet 222 Thermal paste 300 Vehicle display device (Example 3) 400 Vehicle display device (Example 4) 410 Heat sink Di Spacing

Claims

1. A vehicle display device comprising: a display panel for displaying an image that can be projected onto the windshield of a vehicle; a plurality of light sources used for transmitted illumination of the display panel; a controller for controlling the display panel and the plurality of light sources; 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 the controller is 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 and the second substrate into the cooling air.

2. The vehicle display device according to claim 1, further comprising: a driver IC that drives the plurality of light sources by a control signal of the controller; and a board-to-board connector that can be electrically connected between the first board and the second board, wherein the driver IC is mounted on the first surface of the first board; the board-to-board connector is composed of a first connector mounted on the first back surface of the first board and a second connector that is detachably attached to the first connector and mounted on the second surface of the second board; and the heat dissipation member has a contact surface that can thermally and uniformly contact the first back surface of the first board and has a passable portion through which the first connector can pass.

3. The vehicle display device according to claim 2, wherein the second connector on the second substrate is lighter than the first connector on the first substrate, and the second back surface of the second substrate is equipped with, in addition to the controller, a power connector that can be connected to an external power supply, a real vehicle video signal input connector that can be connected to a vehicle-side control unit, a display panel connection connector that can be connected to the display panel, and a power supply circuit that supplies power to the controller and the driver IC.

4. A vehicle display device according to claim 1 or 2, further comprising: a driver IC that drives the plurality of light sources in response to a control signal from the controller; and peripheral components electrically connected to the driver IC, wherein the driver IC and the peripheral components are mounted on the first back surface of the first substrate; and the heat dissipation member has a contact surface that can make thermally uniform contact with the first back surface of the first substrate, and at least one recess that is recessed from the contact surface and capable of surrounding the driver IC and the peripheral components, and the recess has a bottom surface that can make thermal contact with the driver IC and the peripheral components.

5. A vehicle display device according to claim 1 or 2, further comprising: a driver IC that drives the plurality of light sources in response to a control signal from the controller; and peripheral components electrically connected to the driver IC, wherein the peripheral components are mounted on the first surface of the first substrate; the driver IC is mounted on the first back surface of the first substrate; the heat dissipation member has a contact surface that can make thermally uniform contact with the first back surface of the first substrate; and a recess that is recessed from the contact surface and can surround the driver IC; and the recess has a bottom surface that can make thermal contact with the driver IC.

6. The vehicle display device according to claim 4 or 5, wherein the driver IC and the bottom surface of the recess are in close contact via a heat dissipation sheet or thermal paste.

7. The vehicle display device according to claim 1, wherein the second surface of the second substrate completely covers the cooling airflow path from the inlet to the outlet.

8. The vehicle display device according to claim 1, wherein the fin extends from the heat dissipation member toward the second surface of the second substrate, and a sealing member is interposed between the tip of the fin and the second surface of the second substrate.

9. The vehicle display device according to claim 8, wherein the sealing member is conductive.

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