Light-generating device for a head-up display of a motor vehicle

Description

[0001] The invention relates to a light-generating device for a head-up display of a motor vehicle, comprising a circuit board and at least two light-emitting diodes connected in series by means of conductor tracks and arranged in a row on a front side of the circuit board, the respective orientation of which on the front side is determined by the alignment of a cathode side and an anode side of the respective light-emitting diode. The invention also relates to a head-up display with such a light-generating device and a corresponding motor vehicle.

[0002] In known head-up displays (HUDs) in motor vehicles, a mirror is used to project information in a specific direction. This mirror can be the windshield or a so-called combiner mirror, which has a semi-transparent mirror surface that allows information projected onto the mirror from the head-up display, which is reflected by the mirror, to be superimposed with information from the surroundings of the vehicle behind the mirror that shines through the mirror. In a head-up display with a combiner mirror (cHUD), the mirror can be retracted or folded when the display is not needed.The information projected onto the mirror is generated by a light source or a light-generating device of the head-up display. This typically involves light-emitting diodes arranged on a circuit board.

[0003] For example, WO 2015 / 017834 A2 shows a device for collecting and projecting light of a given luminance. A lens can be attached to a holder, which in turn is arranged on a circuit board with LEDs.

[0004] US 20120218479 A1 discloses a lighting unit comprising a rectangular circuit board and a plurality of light sources arranged in rows and columns on the circuit board and electrically connected in series in the row and line directions. Further relevant prior art is DE202007015174A.

[0005] The object is to provide an improved light generating device for a head-up display device of a motor vehicle, which in particular realizes more effective and efficient light generation in the head-up display device.

[0006] This problem is solved by the independent patent claims. Advantageous embodiments emerge from the dependent patent claims, the description, and the figures.

[0007] The invention comprises a light-generating device for a head-up display or head-up display device of a motor vehicle. The light-generating device is, in particular, a light source device for the head-up display (HUD). A virtual image of the head-up display is generated from the light of the light-generating device by means of an image-generating device, for example a TFT display, which is then projected onto a projection surface. It can also be referred to as an illumination device. The light-generating device comprises a circuit board and at least two light-emitting diodes connected in series by means of at least one conductor track and arranged in a row on a front side of the circuit board. The respective orientation of said light-emitting diodes on the front side in the plane of the front side is determined by an alignment of a cathode side and an anode side of the respective light-emitting diode.Preferably, the light generating device here comprises a plurality of light-emitting diodes (LEDs) which are arranged in a straight row and connected in series.

[0008] Here, the LEDs arranged one after the other in the series circuit are arranged with essentially opposite geometric orientations, i.e., with respect to the respective positions of the cathode and anode sides of the LEDs. The orientation of a side or a surface is determined here and below by an associated normal vector of the respective side or surface. The term essentially is understood here and below to mean identity or a deviation not exceeding a predetermined maximum value. This maximum value for angles within the scope of this disclosure is 15 degrees, preferably 8 degrees, and particularly preferably 3 degrees. The cathode side and anode side can thus point in different directions for each LED, each of which is perpendicular to a main extension direction of the row of LEDs.This results in a serpentine pattern for the conductor tracks between two light-emitting diodes in the case of several light-emitting diodes, in which, for example, a conductor track initially leads from a cathode side or anode side of one light-emitting diode perpendicular to the main direction of extension of the row of light-emitting diodes and then leads under a curve opposite to the previously taken direction back to the anode side or cathode side of a next light-emitting diode.

[0009] This has the advantage that the heat generated by the conductor tracks, particularly in the base area of ​​the LEDs, is conducted away particularly effectively from the respective LED where the heat was generated. Since the conductor tracks on the cathode or anode side of the respective LED run perpendicular to the main direction of extension of the row from the LED, the heat is also carried away by the other LEDs, which are also heat sources. This means that the heat from all LEDs is distributed or spread out as best as possible within the plane of the circuit board. This avoids so-called hotspots, i.e. local heat peaks, near the LEDs or in the row between the LEDs. This improves heat dissipation, increases the service life of the LEDs and makes the LEDs more energy-efficient.

[0010] According to the invention, at least one conductor track, which is a conductor track between, i.e., electrically connected in series between, the LEDs, has a conductor track area on the front side of the circuit board that is many times larger than a respective LED base area occupied by the LEDs on the front side of the circuit board. In particular, the conductor track area can be at least five times, at least ten times, or at least twenty times larger than the LED base area. This can apply in particular to all conductor tracks between the LEDs.

[0011] Because the conductor track area is many times larger than the base area of ​​the LED, the heat generated in the LED can be dissipated particularly quickly, creating a particularly uniform heat distribution on the front of the circuit board. This again prevents temperature peaks and reinforces the advantages already mentioned. Furthermore, this improves the transfer of heat from the conductor track to the circuit board and any heat sink located on the back of the circuit board.

[0012] According to the invention, the conductor track surface is U-shaped. In particular, the conductor track surface can have rectangular, for example square, U-shaped side legs and a strip-shaped U-shaped leg. This has the advantage that, since the U-shaped side legs are arranged essentially perpendicular to the longitudinal direction of the row of LEDs, the heat from the individual LEDs is dissipated particularly well and effectively. With rectangular or square side legs, a maximum conductor track surface size is achieved even with shorter U-shaped side legs, thus maximizing heat distribution away from the LEDs and heat transfer to the circuit board.The strip-shaped U-shaped base leg, which is thinner than the side legs in the transverse direction perpendicular to the longitudinal or main extension direction of the row, limits the heat transfer from one side leg to the other and thus prevents excessive heat from being conducted from one LED to the other. The strip-shaped U-shaped base leg advantageously adjoins the U-shaped side legs at an end region remote from the respective LEDs.

[0013] In a further advantageous embodiment, the conductor track area extends in a transverse direction perpendicular to a main extension direction of the row, i.e., perpendicular to the longitudinal direction of the row, of the LEDs over at least 50 percent, in particular over at least 75 percent or at least over 85 percent of the width of the circuit board in the transverse direction. This has the advantage of maximizing the heat dissipation capacity away from the LED and, at the same time, maximizing the heat transfer capacity from the conductor track to the circuit board and / or, if applicable, a heat sink located behind the circuit board. This, in turn, increases the service life and efficiency of the light-generating device.

[0014] In a particularly advantageous embodiment, the conductor track area extends beyond the circumference of a housing or beyond the housing of the LED on both sides in the main extension direction of the row of LEDs, in particular at least on the side of the conductor track or the conductor track area that is electrically connected to the LED. This has the advantage that the surface of the conductor track is maximally increased within a predetermined distance from the LED as the heat source, thus optimizing the dissipation and distribution of heat from the LED to the conductor track.

[0015] In another advantageous embodiment, a heat sink is arranged on a back side of the circuit board, oriented opposite the front side of the circuit board, and is thermally coupled to the circuit board. This has the advantage that the waste heat from the LEDs, distributed via the conductor tracks, can be conducted particularly well through the circuit board.

[0016] In particular, the circuit board can have an aluminum core, for example, to improve heat dissipation from the conductor tracks. The circuit board can also have one or more channels between at least one conductor track and the heat sink, which channels are filled with an electrically insulating material that is more thermally conductive than the circuit board. This can further improve the thermal coupling between the at least one conductor track and the heat sink.

[0017] In a further advantageous embodiment, it is provided that the light-emitting diodes each have a main optical axis which is oriented substantially perpendicular to the front side of the circuit board. The main optical axis here corresponds to a main exit direction of a light from the respective light-emitting diode. The light-emitting diodes here also have a housing with a first outer side running substantially parallel to the main optical axis and with a second outer side diametrically opposite the first outer side and running substantially parallel to the main optical axis. The first outer side of the housing is arranged at a smaller distance from the main optical axis than the second outer side of the housing. The housing is thus arranged unevenly around the main optical axis for a given outer contour of the housing in a plane parallel to the front side of the circuit board.This has the advantage that by cleverly arranging the LEDs, the dimensions can be adapted to different conditions or effects.

[0018] The optical axes of the LEDs can be arranged equidistantly in the row, resulting in particularly homogeneous illumination, as desired for a head-up display. The LEDs can also be identical in design.

[0019] For example, it can be provided here that the first outer sides of the housings of the first and last LEDs in the row are oriented opposite each other and point away from each other. This has the advantage that, for a given distance between the main optical axes of the first and last LEDs, the overall distance between the outer sides oriented outward from the row of LEDs in the longitudinal direction is minimized. This saves installation space and allows, for example, additional elements such as a reflector to be arranged particularly close to the main optical axes of the LEDs, which again enables both thermal advantages and advantages with regard to more homogeneous bundling of the light from the LEDs by the reflector.

[0020] In a further embodiment, it can be provided that two first outer sides of middle LEDs, i.e. LEDs which, when there are more than three LEDs in the row, are not arranged at the end of the row, are oriented opposite each other in the row and facing each other. The middle LEDs are in particular the two LEDs which are arranged centrally in the middle, i.e. the geometric center in a straight line running through the row. This has the advantage that the distance between the outer sides of the respective housings between the middle LEDs is particularly large, so that space is created here for further elements or components without the position of the main optical axes of the LEDs having to be changed.This is particularly advantageous because the precise positioning of the main optical axes is important for the inhomogeneity of the generated light, which is particularly crucial for head-up displays. This allows the desired mechanical properties to be realized regardless of the optical constraints.

[0021] In this case, it can be provided, for example, that a centering device is arranged in a region of the circuit board which lies geometrically between the middle LEDs. This can, for example, comprise a centering pin and / or a centering hole. In particular, the centering device can be arranged on the straight line running through the row. This has the advantage that, on the one hand, the LEDs can be centered or positioned particularly precisely at a predetermined position on the circuit board during assembly, since the centering device is located as close as possible to the row and the LEDs. Furthermore, the same centering device can also be used, for example, to center another optical element such as a reflector. Here, too, the centering device is arranged close to, orin the series of LEDs is particularly advantageous, moreover the accuracy is increased by using the same centering direction for other elements and mounting the LEDs on the circuit board.

[0022] It can also be provided here that the light-generating device has a reflector arranged on the front side of the circuit board, which has a centering element corresponding to the centering device for centering or positioning the reflector relative to the circuit board. This also results in the aforementioned advantages for the reflector. The reflector, in particular, should be arranged particularly close to and precisely oriented relative to the LEDs, so that the aforementioned advantages are particularly beneficial here.

[0023] In a further embodiment, the light-generating device comprises a reflector arranged on the front side of the circuit board, which reflector comprises at least one support element for supporting the reflector on the circuit board in a respective adjacent region adjacent to the two first outer sides of the first and last LEDs and / or to the two first outer sides of the two middle LEDs in a geometric extension of the row or in the row on the circuit board. A support element for supporting between two middle LEDs arranged in the exact center of the row is particularly advantageous here.This has the advantage that the reflector, which must be positioned particularly precisely relative to the LEDs in order to optimize the light quality in the head-up display, can be supported very close to the LEDs as light sources, so that deformation and the like of the reflector, which could deteriorate the quality of the light in the head-up display, is prevented or reduced.

[0024] It is particularly advantageous if, as described above, a heat sink is arranged on the back of the circuit board, and the reflector is attached to the heat sink, and the circuit board is pressed against the heat sink with its back by the at least one spacer element. Because the reflector is attached to the heat sink, the support element can prevent, for example, air gaps from forming between the back of the circuit board and the heat sink, which are detrimental to heat dissipation from the conductor tracks to the heat sink. This results in a sandwich structure of the circuit board, consisting of the reflector, circuit board, and heat sink.

[0025] The invention also relates to a head-up display device with a light-generating device according to one of the aforementioned embodiments. A motor vehicle with such a head-up display device is also encompassed by the invention.

[0026] The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combination specified, but also in other combinations without departing from the scope of the invention. Thus, embodiments are also to be considered encompassed and disclosed by the invention that are not explicitly shown and explained in the figures, but which emerge from the explained embodiments and can be produced by separate feature combinations, as defined in the attached set of claims. Embodiments and feature combinations are also to be considered disclosed that therefore do not have all the features of an originally formulated independent claim.Furthermore, embodiments and combinations of features are to be regarded as disclosed, in particular by the embodiments set out above, which go beyond or deviate from the combinations of features set out in the reliances of the claims.

[0027] Embodiments of the invention are explained in more detail below with reference to schematic drawings.

[0028] Showing: Fig. 1 shows a plan view of a front side of an exemplary embodiment of a light-generating device; Fig. 2 shows a sectional view of another exemplary embodiment of a light-generating device with a cutting plane running perpendicular to the front side along the main extension direction of the row; Fig. 3 shows a perspective view of an exemplary embodiment of a head-up display; and Fig. 4 shows a symbolic representation of a motor vehicle with another embodiment of a head-up display.

[0029] Identical or functionally equivalent features are provided with the same reference symbols in the figures.

[0030] In Fig. 1 An exemplary embodiment of a light-generating device is shown from a front side. The light-generating device 1 has a substantially rectangular circuit board 2 in this case and at least two, here four, light-emitting diodes 3, which are attached, for example soldered, to the front side 4 of the circuit board 2. The light-emitting diodes 3 each have a housing 5 with a cathode side 6 and an anode side 7. For the sake of clarity, only one of the light-emitting diodes 3 is provided with the respective reference numeral. The orientation of the respective light-emitting diode 3 is determined by the alignment of the cathode or anode side 6, 7. The light-emitting diodes 3 each also have a main optical axis 8, which determines the main exit direction of a light generated by the respective light-emitting diode 3 and which, in this case, is perpendicular to the plane of the drawing.The circuit board 2 also has a centering device 9, which can be designed, for example, as a centering hole. The illustration is shown here in the . Fig. 1 symbolic. The circuit board 2 also has an electrical connection to supply power to the LEDs 3.

[0031] The LEDs 3 are now arranged on the front side 4 along a row, the main direction of which in this case is the x-direction and thus a longitudinal direction of the circuit board 2. In the example shown, the LEDs 3 that are geometrically adjacent in the row are also the LEDs 3 that are electrically adjacent in the series circuit.

[0032] The anode side 7 and cathode side 6 of the LEDs 3 arranged consecutively in the series circuit are arranged with essentially opposite geometric orientations. Thus, the cathode side 6 of one LED 3 points in the positive y-direction, and that of the adjacent LED 3 points in the negative y-direction. The same applies mutatis mutandis to the anode sides 7. This also means that with regard to the orientation of one LED 3 relative to another, the position of the anode side 6 and the cathode side 7 is assessed, and the directly adjacent LEDs 3 are each considered. In particular, the LEDs arranged directly next to one another are therefore positioned offset by 180° from one another, with the axis of rotation oriented perpendicular to the circuit board 2 with respect to the offset.In the exemplary embodiment, the light-emitting diodes 3 are arranged such that an imaginary connection between an anode side 6 and a cathode side 7 of a light-emitting diode 3 is directed in the width direction (y-direction) of the circuit board 2.

[0033] In the series circuit, i.e. electrically between the light-emitting diodes 3, respective conductor tracks 10 are arranged on the front side 4 of the circuit board 2, each electrically coupling a cathode side 6 of a light-emitting diode 3 to the anode side 7 of an adjacent light-emitting diode 3 in the series circuit. The conductor tracks 10 can, for example, be made of copper or comprise copper. According to the invention, the conductor tracks 10 in this case each have a U-shaped conductor track surface 11, each of which is oriented with square U-shaped side legs 11a, 11b towards the straight row of light-emitting diodes 3. A strip-shaped U-shaped bottom leg 11c is thus arranged in this case at the end of the U-shaped side legs 11a, 11b further away from the light-emitting diodes 3. At the ends of the U-side legs 11a, 11b remote from the U-bottom leg 11c, the light-emitting diodes 3 are thus contacted with their anode and cathode, respectively.

[0034] In the example shown, on the head side facing the LEDs 3, the U-shaped side legs 11a, 11b each extend in the x-direction, i.e., in the longitudinal direction or main extension direction of the row, beyond the respective housing 5 of the corresponding LED 3. In a transverse direction perpendicular to the main extension direction of the row, the conductor track surfaces 11, at least here with their U-shaped side legs 11a, 11b, extend over more than 50 percent of the width of the circuit board 2 in the transverse direction.

[0035] The housings 5 ​​of the light-emitting diodes 3, which are designated as light-emitting diodes 3a, 3b, 3c and 3d in the row for the purpose of further explanation, have a first outer side 12 in the example shown, which runs parallel to the main optical axis 8, and a second outer side 13, which also runs parallel to the main optical axis 8, but is diametrically opposite the first outer side 12 with respect to the main optical axis 8. In the example shown, the first outer sides 12 of the first light-emitting diode 3a and the last light-emitting diode 3d in the row are opposite each other and point away from each other in the positive and negative x-direction. Furthermore, the light-emitting diodes 3a to 3d are asymmetrical. This means that the main axis 8 is formed at different distances from the outer sides 12 and 13.Since the first outer sides 12 are each spaced a shorter distance from the main optical axis 8 than the second outer sides 13, the total distance 14 between the first outer sides 12 of the two LEDs 3a, 3d is minimized for a given distance between the main optical axes 8 belonging to the two LEDs 3a, 3d. This minimizes the space required for the row, and additional elements can be installed particularly close to the row and its optical axes 8.

[0036] In the example shown, the two middle LEDs 3b, 3c, which in this case are also arranged in the middle of the row or in the geometric center of the row, are arranged with their first outer sides 12 facing each other. This results in a maximized distance 15 between the two housings 5 ​​of the two LEDs 3b, 3c, which is larger than in other arrangements. Thus, the space between the LEDs 3b, 3c can be better utilized for other purposes.

[0037] In the example shown, the centering device 9 is arranged centrally in the row between the two LEDs 3b, 3c. The increased distance 15 can also serve to provide stable support for additional elements on the circuit board.

[0038] Fig. 2 shows a perspective sectional view through an exemplary embodiment of a light-generating device in a plane perpendicular to the front side and parallel to the main extension direction of the row. In the example shown, a heat sink 17 is arranged on a rear side 16 of the circuit board 2, oriented opposite the front side 4.

[0039] In addition to the Fig. 1 Unlike the known LEDs 3, the circuit board 2 in this case has a centering device 9 designed as a centering hole. This is arranged here between the middle LEDs 3b and 3c in the row of LEDs 3.

[0040] As an additional optical element, the light-generating device 1 in the example shown also has a reflector 18, which is arranged on the front side 4 of the circuit board 2. This reflector 18 is supported on support surfaces 19 (19a to 19g) on ​​the circuit board 2 on its front side 4. Two of the support surfaces 19a, 19g are assigned to a circumferential collar 20 of the reflector 18 for lateral stabilization, while the other support surfaces 19b to 19f are assigned to a rear side 21 of a reflection surface 22 of the reflector 18 adjacent to the circuit board 2. The two support surfaces 19b and 19f guide the reflecting surface 22 close to the main optical axes 8 of the first and last light-emitting diodes 3a, 3d, which is possible due to the outward, i.e. away from each other, orientation of the first outer surfaces 12 of the light-emitting diodes 3a and 3d.In the present case, a further support surface 19c is arranged in the row between the LEDs 3a and 3b, a central support surface 19d between the middle LEDs 3b and 3c and a third support surface 19e between the LEDs 3c and 3d.

[0041] Since the middle LEDs 3b and 3c are oriented with their first outer surfaces 12 toward a center of the row, a particularly large installation space is created for the third support surface 19d, which in turn results in stable support of the reflector 18 on the circuit board 2. In the example shown, this installation space is also utilized by the centering device 9, which is assigned a centering pin 23 on the side of the reflector 18. Accordingly, the centering device 9 can serve both to center and position the reflector 18 and the circuit board or the LEDs 3 during assembly.

[0042] The support surfaces 19a to 19g, particularly the central support surfaces 19b to 19f, allow the circuit board 2 to be pressed against the heat sink 17 in the area of ​​the conductor tracks 10. This results in improved heat dissipation. Furthermore, the support surfaces can stabilize the reflector 18 and hold it precisely in its position, thus improving the accuracy of the light-generating device 1.

[0043] The reflector 18 can also be connected, for example screwed, to the heat sink 17 to hold it on the circuit board 2, so that then a good thermal contact between the heat sink 17 and the circuit board 2 is achieved in the manner of a sandwich.

[0044] Fig. 3 shows a perspective view of an exemplary heads-up display 24. In the example shown, the heads-up display 24 has an exemplary embodiment of a light-generating device 1 with a circuit board 2 and a reflector 18, which is arranged on the front side 4 of the circuit board 2. The heads-up display 24 here also has a second circuit board 25, on which, for example, control electronics and the like are mounted. The two circuit boards 2, 25 are tilted relative to one another in this case. The heads-up display 24 here also has a mirror 26, which is also referred to as a combining mirror due to the type of heads-up display 24, as well as further optical components 27 and a mirror 28, which are arranged in an optical path 29 of a light generated by the light-generating device 1.The mirror 26 is the last mirror in the projection beam path of the virtual image to be generated, with which the image is then reflected directly to the observer.

[0045] Fig. 4 shows a view of an exemplary motor vehicle 30 with an exemplary embodiment of a head-up display 24. The motor vehicle 30 here has a head-up display 24, which is arranged, for example, in a dashboard of the motor vehicle and which, with the light generating device 1, projects a light into the eye of a driver 31 via the mirror 28 and the combining mirror 26 along an optical path 29. This light is superimposed with light from an environment of the motor vehicle 30 falling through the windshield 32, which is separate from the mirror 26.

Claims

1. Light-generating device (1) for a head-up display (24) of a motor vehicle (30), having - a printed circuit board (2); and - at least two light-emitting diodes (3, 3a, 3b, 3c, 3d) which are connected in series by means of at least one conductor track (10, 10a, 10b, 10c) and arranged in a row on a front side (4) of the printed circuit board (2) and whose respective orientation on the front side (4) is determined by an alignment of a cathode side (6) and an anode side (7) of the respective light emitting diode (3, 3a, 3b, 3c, 3d), characterized in that the light-emitting diodes (3, 3a, 3b, 3c, 3d) which follow each other in the series circuit are arranged substantially in opposite geometric orientations, wherein at least one conductor track (10, 10a, 10b, 10c), which is a conductor track (10, 10a, 10b, 10c) between the light-emitting diodes (3, 3a, 3b, 3c, 3d), has a conductor track surface (11) on the front side (4) of the printed circuit board (2) that is many times larger, in particular at least 5 times, 10 times or 20 times larger, than a respective light-emitting diode base area taken up by the light-emitting diodes (3a, 3b, 3c, 3d) on the front side (4) of the printed circuit board (2), and the conductor track surface (11) is U-shaped, in particular, with quadrilateral U-shaped side limbs (11a, 11b) and a strip-shaped U-shaped base limb (11c).

2. Light-generating device (1) according to Claim 1, characterized in that in a transverse direction perpendicular to a main extension direction of the row of light-emitting diodes (3, 3a, 3b, 3c, 3d), the conductor track surface (11) extends over at least 50%, in particular over at least 75%, of the width (33) of the printed circuit board (2) in the transverse direction.

3. Light-generating device (1) according to Claim 1 or 2, characterized in that in the main extension direction of the row of light-emitting diodes (3, 3a, 3b, 3c, 3d), the conductor track surface (11) extends beyond the extent of at least one housing (5) of a light-emitting diode (3a, 3b, 3c, 3d) on both sides, in particular at least on the side electrically connected to a light-emitting diode (3a, 3b, 3c, 3d).

4. Light-generating device (1) according to any of the preceding claims, characterized in that a heatsink (17) is arranged on a back side (16) of the printed circuit board (2) that is opposite to the front side (4) of the printed circuit board (2).

5. Light-generating device (1) according to any of the preceding claims, characterized in that the light-emitting diodes (3, 3a, 3b, 3c, 3d) each have an optical main axis (8) and respective housings (5) of the light-emitting diodes (3, 3a, 3b, 3c, 3d) each have a first external side (12) that extends substantially parallel to the optical main axis (8) and a second external side (13) that is diametrically opposite to the first external side (12) and extends substantially parallel to the optical main axis (8), wherein the first external side (12) of a housing (5) is arranged at a shorter distance from the optical main axis (8) than the second external side (13) of the housing (5).

6. Light-generating device (1) according to Claim 5, characterized in that the first external sides (12) of the housings (5) of the first and last light-emitting diodes (3a, 3d) in the row are in the opposite sense and oriented in a manner facing away from each other.

7. Light-generating device (1) according to Claim 5 or 6, characterized in that two first external sides (12) of central light-emitting diodes (3b, 3c) in the row are in the opposite sense and oriented in a manner facing towards each other, wherein the central light-emitting diodes (3b, 3c), in particular the two light-emitting diodes (3b, 3c), are in the centre of the row.

8. Light-generating device (1) according to Claim 7, characterized in that a centring device (9), in particular a centring pin and / or a centring hole, is arranged in a region of the printed circuit board (2) between the central light-emitting diodes (3b, 3c).

9. Light-generating device (1) according to Claim 8, characterized in that the light-generating device (1) comprises a reflector (18) that is arranged on the front side (4) of the printed circuit board (2) and comprises a centring element (23) corresponding to the centring device (9) for centring the reflector (18) relative to the printed circuit board (2).

10. Light-generating device (1) according to any of Claims 6 to 9, characterized in that the light-generating device (1) comprises a reflector (18) that is arranged on the front side (4) of the printed circuit board (2) and at least one support element (19, 19a-19g) for supporting the reflector (18) on the printed circuit board (2) in a respective adjacent region on the printed circuit board (2) that adjoins the two first external sides (12) of the first and last light-emitting diodes (3a, 3d) and / or the two first external sides (12) of the two central light-emitting diodes (3b, 3c).

11. Light-generating device (1) according to Claims 4 and 10, characterized in that the reflector (18) is secured to the heatsink (17), and the back side (16) of the printed circuit board (2) is pressed against the heatsink (17) by the at least one support element (19, 19a-19g).

12. Head-up display (24) having a light-generating device (1) according to any of the preceding claims.

13. Motor vehicle (30) having a head-up display (24) according to Claim 12.