HEAD-UP DISPLAY DEVICE FOR A MOTOR VEHICLE

Abstract

A head-up display apparatus for a motor vehicle is disclosed. The head-up display includes a housing part in which an image creation unit of the display apparatus is arranged, and an illumination device, by means of which light is applied to the image creation unit. The image creation unit is configured to provide an image which is projectable onto a light transmissive projection surface. A holding device is secured to the housing part in the region of the illumination device. The image creation unit is retained on the holding device.

Claims

1. A head-up display apparatus for a motor vehicle, the head-up display comprising: a housing part in which an image creation unit of the display apparatus is arranged, wherein the image creation unit is configured to provide an image which is projectable onto a light-transmissive projection surface, and an illumination device, by means of which light is applied to the image creation unit, wherein a holding device is secured to the housing part in the region of the illumination device, wherein the image creation unit is retained on the holding device.

2. The head-up display apparatus as claimed in claim 1, wherein the image creation unit comprises a pane arrangement which is in direct contact with the holding device and retained by means of the holding device.

3. The head-up display apparatus as claimed in claim 2, wherein at least one pressure-exerting holding arm of the holding device rests against an upper narrow side of the pane arrangement in terms of the vertical direction of the display apparatus, or wherein a lower narrow side of the pane arrangement in terms of the vertical direction of the display apparatus rests on at least one support element of the holding device and is supported by means of the at least one support element.

4. The head-up display apparatus as claimed in claim 2, wherein the holding device comprises a plurality of abutment points, against which a back side of the pane arrangement facing the illumination device rests.

5. The head-up display apparatus as claimed in claim 2, wherein the holding device comprises a stop element against which a lateral narrow side of the pane arrangement in terms of a vertical direction of the display apparatus is pressed, with the holding device comprising a spring element on a side opposite the stop element, wherein the spring element applies a pressure directed at the stop element to a further lateral narrow side of the pane arrangement.

6. The head-up display apparatus as claimed in claim 1, wherein the holding device comprises a holding frame, wherein a chamber of the display apparatus is delimited by the holding frame and by a carrier part, on which at least one light source of the illumination device is arranged, and wherein the image creation unit is arranged in front of a front-side light emergence opening of the chamber.

7. The head-up display apparatus as claimed in claim 1, wherein a diffuser element configured to scatter the light emitted by the illumination device during the operation of the illumination device is retained by means of the holding device.

8. The head-up display apparatus as claimed in claim 7, wherein the light emergence opening of the chamber is sealed by means of the diffuser element, wherein the chamber is configured to reflect light on the inner side or is provided with a reflector device on the inner side.

9. The head-up display apparatus as claimed in claim 1, wherein at least an end region of the holding device is engaged with a carrier part of the illumination device that is secured to the housing part.

10. The head-up display apparatus as claimed in claim 1, wherein the holding device comprises two holding lugs which are formed in one piece with a main body of the holding device, wherein the holding device is secured to the housing part by means of respective screws which are guided through passage openings formed in the holding lugs.

11. The head-up display apparatus as claimed in claim 1, wherein the image creation unit is in the form of a liquid crystal electronic visual display.

Description

[0036] Further features of the invention can be found in the claims, the figures, and the description of the figures. In the figures:

[0037] FIG. 1 shows, in perspective and in sections, components of a head-up display apparatus for a motor vehicle, wherein a holding device secured to a housing part of the display apparatus directly retains a pane arrangement of an image creation unit of the head-up display apparatus;

[0038] FIG. 2 shows the display apparatus according to FIG. 1 in a partly cut-open plan view; and

[0039] FIG. 3 shows, in perspective and in sections, the display apparatus according to FIG. 1 in a frontal view of a front side of the pane arrangement.

[0040] FIG. 1 shows sections of a housing part 12 of a head-up display apparatus for a motor vehicle, said head-up display apparatus, for reasons of simplicity, also merely being referred to as a display apparatus 10 below. In relation to an installed position of the display apparatus 10 in the motor vehicle, the housing part 12 is a lower housing part 12 of the display apparatus 10 in the present case.

[0041] An upper housing part (not shown) of the display apparatus 10 is arranged on the lower housing part 12 when the display apparatus 10, which is also referred to as a head-up display, is in the state where it is installed in the motor vehicle (not shown). The upper housing part has an emergence opening which is provided with a light-transmissive film or a similar covering and by means of which an image can be projected onto a light-transmissive projection surface. For example, the windshield of the motor vehicle can serve as this light-transmissive projection surface.

[0042] The image projected onto the projection surface is provided by an image creation unit 14 of the display apparatus 10. In the present case, the image creation unit 14 is in the form of an active matrix display with thin-film transistors and can therefore also be referred to as a TFT (thin-film transistor) display.

[0043] The image creation unit 14 comprises a pane arrangement 16 which has two panes (not shown in detail in the present case), in particular glass panes, and the thin-film transistors arranged between the two panes. In the present case, the pane arrangement 16 is retained directly on a holding device 18, which in turn is secured to the housing part 12.

[0044] For this purpose, the holding device 18 may comprise two holding lugs 20, 22, by means of which the holding device 18 is secured to the housing part 12. In the present configuration of the display apparatus 10 shown by way of example, respective screws 24 are guided through passage openings formed in the holding lugs 20, 22 (compare FIG. 2).

[0045] The holding device 18 also comprises a holding frame 26 which delimits a chamber 28 (compare FIG. 2) of the display apparatus 10 in the circumferential direction. As shown by way of example in the present case, a reflector device or a reflector 30 may be arranged in the chamber 28 which is formed or delimited in regions by the holding frame 26 of the holding device 18.

[0046] The reflector 30 ensures a high light yield when operating an illumination device 32 (compare FIG. 2) of the display apparatus 10. In the present case, the illumination device 32 is provided or designed to provide backlighting for the image creation unit 14. Accordingly, during the operation of the display apparatus 10, light emitted by light sources of the illumination device 32 is applied to the image provided by means of the image creation unit 14.

[0047] In this respect, light sources in the form of light-emitting diodes 34 are shown schematically in FIG. 2, only some of which have been provided with a reference sign for reasons of clarity. On account of the provision of the reflector 30 arranged on an inner side of the holding frame 26 (compare FIG. 2), the light emitted by the light-emitting diodes 34 is used to a particularly large extent for the purpose of applying light to, or providing backlighting for, the image creation unit 14.

[0048] Moreover, a diffuser element or a diffuser 36, shown in section in FIG. 2, can be arranged on the path of the light from the light sources, presently in the form of the light-emitting diodes 34, to the image creation unit 14. In particular, the diffuser 36, for example designed as a light-transmissive plastic panel, or such a light diffuser ensures a uniform impingement of light emitted by the light-emitting diodes 34 upon the image creation unit 14.

[0049] Since the diffuser 36 is retained on the holding device 18 in the case of the display apparatus 10 presently shown by way of example, the holding device 18 can be referred to as a diffuser holder in the present case. In the case of this display apparatus 10, the light-transmissive diffuser 36 seals or covers a front-side light emergence opening of the chamber 28 delimited by the holding frame 26 in the circumferential direction (compare FIG. 2).

[0050] In the rearward direction or on a back side, the chamber 28 is delimited by a carrier part in the form of a printed circuit board 38, on which the light sources, presently in the form of the light-emitting diodes 34, are retained (compare FIG. 2). The printed circuit board 38 therefore serves as a carrier part for the light sources of the illumination device 32. Just like the holding device 18, the printed circuit board 38 is presently also screwed to the housing part 12 by means of at least one screw 40 (compare FIG. 2).

[0051] The image provided by the image creation unit 14 during the operation of same is projected via at least one mirror (not shown) through the emergence opening formed in the upper housing part (likewise not shown) of the display apparatus 10 onto the projection surface, for instance in the form of the windshield of the motor vehicle. For example, a mirror of the display apparatus 10 which ensures an enlargement of the image can be used for this projection of the image onto the projection surface.

[0052] Especially for this reason, but also in order to project the image onto the projection surface via the emergence opening in a manner that is as free from distortions and as complete as possible, it is advantageous if the image creation unit 14 is positioned very precisely relative to the housing part 12, as is also the case in the presently shown display apparatus 10. This precise positioning of the image creation unit 14 is achieved by the holding device 18, and this is explained in detail below.

[0053] Firstly, it is evident, especially from FIG. 1, that the pane arrangement 16 of the image creation unit 14, i.e. the pane package presently comprising two panes, is in immediate contact with the holding device 18 or directly retained on the holding device 18.

[0054] This is because, unlike in the case of the image creation unit 14 shown presently in exemplary fashion, there are TFT displays which have frame-shaped diaphragms which enclose the pane arrangement or the pane package. In this context, a diaphragm or a diaphragm-shaped frame can be arranged in particular on a front side of the pane package and also on a back side of the pane package. However, if such diaphragm-type frames are retained on a holding device, additional tolerances which are due to the arrangement of the pane arrangement 16 relative to the frame must be taken into account in view of the positioning of the pane arrangement 16.

[0055] However, such frames or diaphragms have been dispensed with in the present case. Accordingly, the pane arrangement 16 is retained directly or immediately on the holding device 18. In particular, the holding device 18 is immediately in contact with at least one pane of the pane arrangement 16 or pane package. A particularly short tolerance chain is achieved as a result. This leads to very precise or accurate positioning of the pane arrangement 16 and hence the optically effective components of the image creation unit 14, optically effective as they provide the image, relative to the housing part 12 of the display apparatus 10.

[0056] A particular advantage of the present frameless pane arrangement 16 is that it enables a direct retention and positioning of the image creation unit 14 on the holding device 18 designed as a diffuser holder in the present case. This positioning of the image creation unit 14 relative to the housing part 12 is maintained precisely, independently of possible tolerances which may afflict the arrangement of the display apparatus 10 in the motor vehicle. Therefore, it is possible to achieve a precise projection of an image, provided or created at least largely without distortions, onto the light-transmissive projection surface by means of the display apparatus 10.

[0057] Advantageously, in addition, the holding device 18 in the form of the diffuser holder also positions the reflector 30 and the image creation unit 14 very precisely relative to one another. This ensures particularly good backlighting for the assembled image creation unit 14 during the operation of the display apparatus 10.

[0058] In the present case, two holding arms 42, 44, emanating from the holding frame 26, are arranged in an upper region of the holding device 18. The two holding arms 42, 44 are spaced apart from one another in a transverse direction x of the display apparatus 10, which just like a vertical direction z of the display apparatus 10 and a depth direction y of the display apparatus 10 is illustrated by a coordinate system in FIG. 1.

[0059] In the present case, the holding arms 42, 44 exert a pressure on an upper narrow side 46 of the pane arrangement 16 in terms of the vertical direction z. For this purpose, respective lugs 48 of the holding arms 42, 44 rest directly against the upper narrow side 46 of the pane arrangement 16. A lower narrow side 50 of the pane arrangement 16, opposite the upper narrow side 46 in the vertical direction z, by contrast rests on two support elements 52, 54 which are formed in one piece with a main body of the holding device 18, just like the holding arms 42, 44 presently designed in resilient or spring-loaded fashion.

[0060] By virtue of the pane arrangement 16 being clamped between the presently resilient holding arms 42, 44 and the support elements 52, 54 in the vertical direction z, the pane arrangement 16 is mounted with great positional accuracy on the holding device 18 in the vertical direction z.

[0061] In the present case, the lugs 48 of the holding arms 42, 44 are spaced apart further from the diffuser 36 in the depth direction y of the display apparatus 10 or chamber 28 than abutment points of the support elements 52, 54, which are spaced apart from one another in the transverse direction x and against which the lower narrow side 50 of the pane arrangement 16 rests. In the present case, this leads to the pane arrangement 16 being oriented with an incline relative to the diffuser 36 while the diffuser 36 substantially extends in the vertical direction z and the transverse direction x. This inclined orientation of the pane arrangement 16, which is depicted partly cut open in FIG. 2, of the image creation unit 14 with respect to the xz-plane is also identifiable in FIG. 2.

[0062] It is also evident from FIG. 2 that a rearward end region 66 of the holding frame 26 may be introduced or engaged in a cutout 68 which is formed in the printed circuit board 38. The rearward end region 66 of the holding frame 26 can be designed to taper toward the printed circuit board 38 for this purpose, as is also evident from FIG. 2. Such interaction between the holding frame 26 and the printed circuit board 38 is advantageous in view of precise positioning of the holding device 18 relative to the illumination device 32.

[0063] A further end region 70 of the holding frame 26 can rest against a narrow side 72 of the printed circuit board 38 on a side of the holding frame 26 opposite to the end region 66 in the transverse direction x. However, provision can also be made for the further end region 70 to engage in a cutout formed in the printed circuit board 38, in a manner analogous to what was described for the first end region 66.

[0064] From FIG. 1 in particular, it is evident that the holding device 18 comprises a plurality of abutment points 56, against which a back side of the pane arrangement 16 facing the illumination device 32 rests. In the present case, the abutment points 56 are arranged in the vicinity of respective corner regions of the pane arrangement 16 presently designed in rectangular fashion (compare FIG. 1).

[0065] The two upper abutment points 56 in the vertical direction z are provided by the holding arms 42, 44 in the present case. By contrast, the two lower abutment points 56 in the vertical direction z are presently arranged adjacent to the support elements 52, 54. If the pane arrangement 16 rests against these abutment points 56 then very precise positioning of the pane arrangement 16 is also obtained in the depth direction y of the display apparatus 10.

[0066] FIG. 3 shows the two upper abutment points 56 in a frontal view. Moreover, it is quite evident, especially from FIG. 3, how precise and positionally accurate retention of the pane arrangement 16 of the image creation unit 14 in the present case is additionally achieved in the transverse direction x by the holding device 18. This is because the holding device 18 firstly comprises a stop element 58, against which a lateral narrow side 60 (compare FIG. 1) of the pane arrangement 16 is pressed.

[0067] In this case, the pressure is exerted by a spring element 62 of the holding device 18, said spring element being opposite the stop element 58 in the transverse direction x. The spring element 62 applies a pressure directed at the stop element 58 on a further lateral narrow side 64 (compare FIG. 1) of the pane arrangement 16. A very precise retention of the pane arrangement 16 on the holding device 18 is also achieved in the transverse direction x by virtue of the spring element 62 pressing the pane arrangement 16 against the stop element 58. Moreover, both the stop element 58 and the spring element 62 rest immediately against the at least one pane of the pane arrangement 16.

[0068] Overall, the examples show how it is possible to provide a head-up display apparatus 10 or a head-up display with a particularly comprehensively shortened tolerance chain in relation to the positioning of the image creation unit 14.