Display device for a motor vehicle, and motor vehicle having such a display device

Abstract

The invention relates to a display device (12) for a head-up display of a motor vehicle (44), in particular for a black-print head-up display of the motor vehicle (44). The display device (12) comprises a housing (26) with a housing body (28), having a housing base (32) and a housing cover (30) which closes off an interior of the housing body (28) from housing surroundings on a housing side arranged opposite the housing base (32), a display panel (18) which is integrated into the housing cover (30) and is designed to project display contents onto a reflection region in the housing surroundings, and a circuit board arrangement (10) comprising a main circuit board (14) and an illuminant circuit board (16), wherein the illuminant circuit board (16) is arranged between the main circuit board (14) and the housing cover (30) in the interior of the housing body (28). At least one ventilation channel (34) is formed in the housing body (28), which ventilation channel is open in the direction of the housing surroundings and is designed to conduct ambient air between the main circuit board (14) and the illuminant circuit board (16) through the housing body (28).

Description

[0001] Display device for a motor vehicle and motor vehicle with such a display device

[0002] The invention relates to a display device for a head-up display of a motor vehicle, in particular for a so-called black-print head-up display. The invention also relates to a motor vehicle with such a display device.

[0003] As is well known, head-up displays work by emitting a generated display content from a display screen and projecting it onto a reflection area. Depending on the geometric design of the beam paths of the projected and reflected light, the projection results in the display content being shown to a viewer at a spatial distance from the actual reflection area.

[0004] This method of providing display content or information has long been known in motor vehicles. In conventional head-up displays, for example, an area of ​​a vehicle's windshield is used as a reflection area. The beam paths are typically selected such that the information to be displayed is perceived by the driver as hovering at a distance of two to ten meters in front of the vehicle or above the hood.

[0005] In addition, there are head-up displays in the automotive sector where the reflection area is located in the area of ​​a black print on the vehicle's windshield. Such head-up displays are also known as black print head-up displays.

[0006] Typically, such a black print area is located at the base or root of the windshield. In other words, the reflection area of ​​the head-up display is located in the area of ​​the base or root of the windshield. Due to the geometric proportions, such black print head-up displays cause no or only a barely noticeable magnification of the display content due to reflection. Accordingly, the display content appears very close to the windshield compared to conventional head-up displays. Such black print projections can be used, for example, to display information in the area of ​​the windshield base that would otherwise have to be shown on displays in the dashboard area.The displays in the dashboard area can be eliminated by using a black-print head-up display, opening up numerous design and layout possibilities in the vehicle interior. Furthermore, particularly high-contrast displays can be realized in the black-print area.

[0007] Display devices for head-up displays, which are designed to generate and emit the display content, generally comprise a circuit board arrangement arranged in a housing. A housing body of such a housing can have a housing base and a housing cover, which can be arranged opposite one another. In other words, an interior of the housing body, in which the circuit board arrangement is arranged, can be sealed off from the housing environment on a housing side arranged opposite the housing base. The aforementioned display panel can be integrated into the housing cover. The display panel can be designed to project the display content to be displayed onto a reflection area in the housing environment, for example, in the direction of the windshield of the motor vehicle.

[0008] The circuit board assembly typically comprises a main circuit board or main printed circuit board and a light-emitting diode board, which may, for example, contain several LEDs (light-emitting diodes) or other suitable light sources. To generate the desired display content, control signals describing the display content can be transmitted from the main circuit board to the light-emitting diode board. The control signals thus describe which of the light sources should emit light and with what brightness or intensity to generate the display content. The display content thus generated travels from the light-emitting diode board to the display disc arranged above it in the direction of radiation, from where it is emitted and projected onto the reflection area.

[0009] With normal displays, i.e. displays that do not function via reflection as described, the viewer sees the displayed content directly. In other words, the viewer sees the display content at the brightness in which it is generated. In the case of the head-up displays described, however, the viewer only sees the reflection of the display content emitted by the display screen. Depending on the design of the reflection area, a loss of brightness of up to 80 percent can occur during reflection. In some cases, for various reasons, the reflection area has a coating that can absorb a large portion of the light emitted by the display screen. In some cases, therefore, the display device for a head-up display must provide five times the intensity of a normal display in order to produce the same brightness for the viewer.To achieve this, the display device for the head-up display must be more powerful than the standard display. This increased power often leads to undesirable heat generation during operation.

[0010] In the case of the black-print head-up displays described above, the limited space directly below the windshield complicates the situation even further: the circuit boards described above must be stacked tightly on top of one another within the housing. This can lead to heat buildup between the boards.

[0011] It is known to counteract this unwanted heat development, for example, with a heat sink located behind the housing. However, this additional component further exacerbates the already limited installation space.

[0012] An object underlying the present invention is therefore to provide an efficient and space-saving cooling system for a display device of the type described.

[0013] The problem is solved by the subject matter of the independent patent claims. Advantageous developments of the invention are described by the dependent patent claims, the following description, and the figures.

[0014] The invention provides a display device for a head-up display of a motor vehicle, in particular for a black-print head-up display of the motor vehicle. The display device according to the invention comprises a housing with a housing body. The housing body has a housing base and a housing cover arranged opposite the housing base. In other words, the housing cover closes off an interior of the housing body from the housing environment on a housing side arranged opposite the housing base. Side walls of the housing extend between the housing base and the housing cover, which can be arranged essentially parallel to one another. The housing can therefore form a closed interior space.

[0015] According to the invention, a display panel is integrated into the housing cover, which is designed to project display content onto a reflective area in the housing's surroundings. The display panel can also form the housing cover.

[0016] Furthermore, the display device according to the invention comprises a circuit board arrangement comprising a main board and a lighting circuit board of the type described above, wherein the lighting circuit board is arranged in the interior of the housing body above or above the main board in the direction of the housing cover. In other words, the lighting circuit board is arranged between the main board and the housing cover in such a way that light emitted by the lighting elements of the lighting circuit board strikes a rear side of the display panel integrated into the housing cover. In other words, the lighting circuit board is arranged between the main board and the housing cover in the interior of the housing.The main board, the lamp board and the display panel of the housing cover thus form a stack, whereby the main board, the lamp board and the display panel of the stack do not have to lie directly on top of each other, but are preferably arranged at a distance from each other.

[0017] The known communication connections for transmitting the corresponding control signals are arranged between the main board, the lamp board, and the display panel. Thus, the control signals that describe which lamps should be controlled to generate the desired display content can be transmitted from the main board or main circuit board to the lamp board or lamp circuit board. Depending on the desired display content, individual or all lamps can illuminate, preferably independently of one another, sequentially, or simultaneously, in particular with different intensities, and emit light toward the back of the display panel.

[0018] According to the invention, at least one ventilation duct is formed in the housing body, which is open toward the housing environment and is designed to conduct ambient air between the main board and the lighting board through the housing body. In other words, the invention provides for an air flow between the main board and the lighting board to dissipate the heat generated by the lighting board. In other words, the inventive solution comprises the integration of the at least one ventilation duct into the housing or the housing body.

[0019] The invention offers the advantage that efficient cooling can be provided without requiring any additional installation space.

[0020] The invention includes further embodiments which provide additional advantages.

[0021] One embodiment provides that the interior of the housing body is fluidically separated from the housing environment by a wall section or a wall of the at least one ventilation duct. In other words, the interior of the housing body does not come into contact with the ambient air. Rather, the at least one ventilation duct, with its wall section, is routed through the housing or the housing body in such a way that the ambient air does not mix with the interior air of the housing body. This advantageously effectively cools the interior of the housing body, in which the circuit board arrangement is located, while still protecting it from contamination caused by the ingress of ambient air.

[0022] The at least one ventilation duct can, for example, be in the form of a completely closed pipe extending from one side of the housing body to the opposite side of the housing body. In this case, the outer surface of the pipe forms the wall section, with the open ends of the pipe being open towards the housing environment so that the ambient air can flow through the pipe. Preferably, the pipe mentioned is inserted or guided through the housing body between the main board and the lighting board. Several such pipes can also be guided parallel to one another through the housing body. The pipes can be fluidically connected to one another along their outer surfaces, which can lead to improved air exchange.

[0023] An advantageous development provides that the wall section of the at least one ventilation duct is formed, at least in part, by an intermediate floor arranged in the housing body between the main board and the lighting circuit board. In other words, the intermediate floor can be arranged in the housing body below the lighting circuit board. The housing can therefore have an intermediate floor extending between the main board and the lighting circuit board. In other words, the wall section of the ventilation duct forms the intermediate floor in the aforementioned embodiment.

[0024] A further development provides that the lamp circuit board is arranged on a side of the intermediate floor facing the interior of the housing body. In other words, the intermediate floor supports the lamp circuit board on its side facing the interior of the housing body. The lamp circuit board can be screwed, plugged, or glued onto the intermediate floor. Preferably, the lamp circuit board is thermally coupled to the side of the intermediate floor facing the interior of the housing body by means of a thermally conductive medium. The thermally conductive medium can be, for example, a thermally conductive paste, a thermally conductive pad, and / or a thermally conductive adhesive tape.

[0025] On the side of the intermediate base facing the interior of the housing body, a reflector grid can additionally be arranged, which is designed to direct the light emitted by the individual lamps of the lamp board towards the display panel. The reflector grid can comprise longitudinal and transverse struts that can intersect and thus form meshes. A lamp can be arranged within a mesh. The longitudinal and transverse struts can have reflective surfaces that can be designed to direct or focus the light emitted by the lamps towards the rear of the display panel. The longitudinal and / or transverse struts can serve as support means for the display panel and carry it at a distance from the lamp board. In other words, the display panel can rest on the longitudinal and / or transverse struts of the reflector grid.

[0026] In contrast, according to a further embodiment, the intermediate floor has cooling fins on a side facing the ventilation duct, which extend into the ventilation duct. In other words, the side of the intermediate floor facing the ventilation duct has elevations that protrude into the air stream of ambient air flowing through the ventilation duct. As a result, a surface area of ​​the side of the intermediate floor facing the ventilation duct is advantageously enlarged for improved heat exchange. In addition, a geometry of the elevations can be designed to improve air flow within the ventilation duct, thereby further improving cooling. A further embodiment provides that the at least one ventilation duct runs at an incline with respect to the housing base and / or with respect to the housing cover.In other words, it can be provided that the at least one ventilation duct does not run parallel to the housing base and / or the housing cover. In other words, an inlet opening of the ventilation duct can be located closer to the housing base and an outlet opening of the ventilation duct closer to the housing cover. The ventilation duct can therefore be guided diagonally through the housing body. The described inclination enables convection in the air flow in the ventilation duct. Convection can create an airflow within the ventilation duct without the need for an additional fan or the like. This would disadvantageously require additional installation space and, under certain circumstances, also lead to undesirable noise development, which can be avoided by the described embodiment.

[0027] Another embodiment provides for a cross-section of the ventilation duct to expand along its length. Depending on the geometry of the ventilation duct, this can further improve efficient air flow within the ventilation duct.

[0028] According to a further embodiment, the housing is made of metal, which leads to effective electromagnetic shielding of the circuit board arrangement. Alternatively, the housing can have at least metallic or metallized components. The wall section of the ventilation duct is preferably also made of metal. The housing is preferably formed integrally with the ventilation duct. In addition to the advantage of electromagnetic shielding, metal as a material has high thermal conductivity, whereby heat dissipation via the intermediate floor can be further improved in the integral design. The metallic housing with the ventilation duct can be manufactured, for example, using a die-casting process. This enables cost-effective production.

[0029] A further aspect of the invention relates to a motor vehicle with a display device according to the invention installed as intended.

[0030] In its intended installation position in the motor vehicle, the housing of the display device is arranged in the region of a windshield of the motor vehicle on a side of an instrument panel trim part facing away from the vehicle interior. The housing can, for example, be arranged in direct proximity to any additional display devices for conventional head-up displays that may also be present.

[0031] In the intended installation position, the display disc integrated into the housing cover is preferably aligned to project the display contents onto the windshield, in particular onto a black print area of ​​the windshield.

[0032] In this case, there is preferably an air gap directed towards the windshield between the housing of the display device and the instrument panel trim part. In the intended installation position of the display device, the at least one ventilation duct is aligned with the air gap such that the ambient air passed through the housing body impinges on the windshield through the air gap. In other words, the spatial conditions in the motor vehicle according to the invention according to the embodiment described here are aligned with the geometric conditions of the described display device such that the described interaction between the at least one ventilation duct in the housing of the display device and the described air gap between the instrument panel trim part and the windshield results.A further advantage of the embodiment described here is that the heated ambient air passed through the housing body can also be used as a type of fan for drying the windshield. In other words, the waste heat from the described display device can be used to dry the windshield.

[0033] In the intended installation position, the at least one ventilation duct of the display device is preferably oriented at an angle toward the air gap to create a convection flow. In other words, the ventilation duct runs from below, for example, from the direction of a footwell of the motor vehicle, upwards toward the air gap, whereby the heated air flows upwards toward the windshield according to the convection flow. This is possible, in particular, even without an additional fan.

[0034] However, it can also be provided that the motor vehicle has a blower device, wherein, in the intended installation position of the display device, at least one air outlet of the blower device is aligned with the air inlet of the at least one ventilation duct of the display device in such a way that the air expelled through the air outlet is prepared for further transmission through the at least one ventilation duct. In other words, the air outlet is aligned with the air inlet of the ventilation duct in such a way that air is blown into the ventilation duct through the air outlet. A blower device already located in the motor vehicle can be used efficiently for this purpose. The cooling of the display device can thereby be further improved.

[0035] Further embodiments of the motor vehicle according to the invention follow directly from the various embodiments of the display device according to the invention, and vice versa. In particular, individual features and corresponding explanations as well as advantages relating to the various embodiments of the display device according to the invention can be transferred analogously to corresponding embodiments of the motor vehicle according to the invention.

[0036] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures can be encompassed by the invention not only in the respectively specified combination, but also in other combinations. In particular, the invention can also encompass embodiments and combinations of features that do not have all the features of an originally formulated claim. Furthermore, the invention can encompass embodiments and combinations of features that go beyond the combinations of features set out in the references to the claims or deviate from them.

[0037] Showing:

[0038] Fig. 1 is a schematic representation of a stack of a main board, a lighting board and a display panel of a display device according to an embodiment of the invention;

[0039] Fig. 2 is a schematic external view of a housing of a display device according to an embodiment of the invention with a ventilation duct extending through a housing body of the housing; Fig. 3 is a schematic representation of a section of a housing according to the representation of Fig. 2 with an indicated air flow; and

[0040] Fig. 4 is a schematic representation of a motor vehicle with a display device in the intended installation position according to an embodiment of the invention.

[0041] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0042] In the figures, the same reference symbols designate elements with the same function.

[0043] Fig. 1 shows a schematic representation of a circuit board arrangement 10 for a display device 12 according to an embodiment of the present invention. The circuit board arrangement 10 comprises a main circuit board 14 and a lighting circuit board 16. Fig. 1 also shows a display panel 18. The three components—main circuit board 14, lighting circuit board 16, and display panel 18—are arranged one above the other or stacked in the configuration shown in Fig. 1. The lighting circuit board 16 lies between the lower main circuit board 14 and the upper display panel 18, with a radiation direction of the lighting elements 22 of the lighting circuit board 16 being directed toward a rear side of the display panel 18.

[0044] The main board 14 and the lighting board 16 can be communicatively connected to one another via communication links 20. Using the communication links 20, control signals can be transmitted from the main board 14 to the lighting board 16. This tells the lighting board 16 which of its individual lighting devices 22, which can be individual LEDs, for example, need to be controlled to display a specific display content along the display panel 18. According to the embodiment shown in Fig. 1, the main board 14, the lighting board 16, and the display panel 18, or a substrate supporting them, are connected to one another via a metallic connecting structure 24. Fig. 1 thus shows, in a sense, the inner workings of the display device 12.

[0045] Fig. 2, in contrast, shows a schematic external view of a display device 12 according to an embodiment of the invention, with reference to the components designated and described in connection with Fig. 1. Shown is a housing 26 with a housing body 28 and a housing cover 30. The housing body 28 can have a cup-shaped basic form with a housing cover 30 and a housing base 32. The housing cover 30 is arranged on a side of the housing body 28 opposite a housing base 32. According to the embodiment shown here, the display disk 18 is integrated into the housing cover 30. The further interior of the housing 26 shown here corresponds to that shown in Fig. 1.

[0046] The housing 26 of Fig. 1 also has a ventilation duct 34 that extends through the housing body 28. In other words, a viewer can see through the ventilation duct 34 through the housing body 28. In the embodiment shown, a total of three ventilation ducts 34 are arranged in the housing body 28, which run side by side between the main board 14 (not visible here) and the lighting board 16 (also not visible). The three ventilation ducts 34 together extend almost across the entire width of the housing 26 or the housing body 28.

[0047] A wall section of each of the ventilation ducts 34 in Fig. 2 provides an intermediate floor 36, at least in sections, which is arranged in the housing body 28 below the lighting circuit board 16 (not visible here). The lighting circuit board 16 can be arranged in the interior of the housing body 28 on the side of the intermediate floor 36 facing the interior. The intermediate floor 36 has cooling fins 38 on a side facing the ventilation duct 34, which extend into the ventilation duct 34. For the sake of clarity, only two of the cooling fins 38 are provided with reference numerals in Fig. 2. The cooling fins 38 advantageously increase the area of ​​the wall section of the ventilation duct 34 available for heat transfer. In addition, the cooling fins 38 can contribute to improved conduction of the ambient air through the ventilation duct 34. Fig. 3 clarifies the explanations for Fig.2 based on a sectional view of the illustrated housing 26. As can be seen in the illustration in Fig. 3, the lighting circuit board 16 is arranged in the interior of the housing body 28 on a side of the intermediate floor 36 facing the interior. The main circuit board 14 is located below the intermediate floor 36 in the lower region of the housing body 28. The lighting circuit board 16 and the main circuit board 14 are thus separated from one another by the intermediate floor 36 and the ventilation duct 34.

[0048] An arrow 40 in Fig. 3 indicates an air flow flowing along the ventilation duct 34 through the housing body 28. To improve the flow characteristics, in the exemplary embodiment shown here, a cross-section of the ventilation duct 34 is widened along the illustrated air flow 40. In other words, the cross-section of the ventilation duct 34 is narrower or smaller on an inlet side of the air flow 40 than on an opposite outlet side.

[0049] Furthermore, with regard to the interior of the display device 12 shown, Fig. 3 shows a reflector grid 40 which is arranged on the illuminant board 16 and has differently oriented longitudinal and transverse struts which serve to guide and / or focus the light emitted by the illuminants 22 in the direction of the display panel 18.

[0050] With reference to the components identified and described in connection with the preceding figures, Fig. 4 shows a schematic representation of a motor vehicle 44 with a display device 12 in its intended installation position. The housing 26 of the display device 12 is arranged in the motor vehicle 44 in the region of a windshield 46 on a side of an instrument panel trim part 48 facing away from the interior of the motor vehicle 44. It can be seen from Fig. 4 that, in its intended installation position, the ventilation duct 34 is oriented toward the windshield 46.

[0051] For illustrative purposes, Fig. 4 also shows a beam path 49 of the display device 12 as a black-print head-up display. If the eye of a driver of the motor vehicle 44 is located within the area 50, they will perceive the image generated and projected by the display device 12 in the area 52. Overall, the exemplary embodiments demonstrate how the invention can provide an efficient and space-saving option for cooling a display device for a black-print head-up display.

Claims

Patent claims 1 . Display device (12) for a head-up display of a motor vehicle (44), in particular for a black-print head-up display of the motor vehicle (44), comprising - a housing (26) with a housing body (28), comprising a housing base (32) and a housing cover (30), wherein the housing cover (30) closes off an interior of the housing body (28) on a housing side arranged opposite the housing base (32) from a housing environment, - a display panel (18) integrated into the housing cover (30) which is designed to project display contents onto a reflection area in the housing environment, and - a circuit board arrangement (10) comprising a main circuit board (14) and a lighting circuit board (16), wherein the lighting circuit board (16) is arranged between the main circuit board (14) and the housing cover (30) in the interior of the housing body (28), characterized in that at least one ventilation channel (34) is formed in the housing body (28), which is open towards the housing environment and is designed to guide ambient air between the main circuit board (14) and the lighting circuit board (16) through the housing body (28).

2. Display device (12) according to claim 1, wherein the interior of the housing body (28) is fluidically separated from the housing environment by a wall section (36) of the at least one ventilation duct (34).

3. Display device (12) according to claim 2, wherein the wall section (36) of the at least one ventilation duct (34) is formed at least in sections by an intermediate floor (36) which is arranged in the housing body (28) between the main board (14) and the lighting board (16).

4. Display device (12) according to claim 3, wherein the illuminant board (16) is arranged on a side of the intermediate floor (36) facing the interior of the housing body (28).

5. Display device (12) according to claim 4, wherein the luminous element board (16) is thermally coupled to the side of the intermediate floor (36) facing the interior of the housing body (28) by means of a thermally conductive medium.

6. Display device (12) according to one of claims 4 or 5, wherein on the side of the intermediate floor (36) facing the interior of the housing body (28) there is additionally arranged a reflector grid (42) which is designed to guide the light emitted by individual illuminants (22) of the illuminant board (16) in the direction of the display panel (18).

7. Display device (12) according to one of claims 3 to 6, wherein the intermediate floor (36) has cooling fins (38) on a side facing the at least one ventilation duct (34) which extend into the ventilation duct (34).

8. Display device (12) according to one of the preceding claims, wherein the at least one ventilation channel (34) runs inclined with respect to the housing base (32) and / or with respect to the housing cover (30).

9. Display device (12) according to one of the preceding claims, wherein a cross section of the at least one ventilation duct (34) widens along the course of the ventilation duct (34).

10. Display device (12) according to one of the preceding claims, wherein the housing (26) is made of metal, or wherein the housing (26) has at least metallic or metallized parts.

11. Motor vehicle (44) with a display device (12) according to one of the preceding claims, wherein the housing (26) in its intended installation position in the motor vehicle (44) in the region of a Windscreen (46) of the motor vehicle (44) on a is arranged on the side of an instrument panel trim part (48) facing away from the motor vehicle interior.

12. Motor vehicle (44) according to claim 11, wherein in the intended installation position the display screen (18) integrated into the housing cover (30) is aligned to project the display contents onto the windshield (46), in particular onto a black print area of ​​the windshield (46) in the area of ​​a windshield root.

13. Motor vehicle (44) according to one of claims 11 or 12, wherein in the intended installation position an air gap directed towards the windshield (46) remains between the housing (26) of the display device (12) and the instrument panel trim part (48), wherein the at least one ventilation duct (34) is aligned with the air gap such that the ambient air passed through the housing body (28) impinges on the windshield (46) through the air gap.

14. Motor vehicle (44) according to claim 13, wherein the at least one ventilation duct (34) of the display device (12) is oriented inclined in the direction of the air gap in the intended installation position to produce a convection flow.

15. Motor vehicle (44) according to one of claims 11 to 14, comprising a blower device, wherein in the intended installation position at least one air outlet of the blower device is aligned with the at least one ventilation duct (34) in such a way that the air expelled through the air outlet is provided for further transmission through the at least one ventilation duct (34).

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