ILLUMINATION DEVICE FOR A MOTOR VEHICLE HEADLIGHT

Description

[0001] The invention relates to a lighting device for a motor vehicle headlight, the lighting device comprising: a printed circuit board, comprising at least one light source connected to the printed circuit board and configured to emit light in a main emission direction, a light guide having one end configured as a light coupling surface, wherein the light guide is assigned to guide light from the at least one light source, which light can be coupled into the light guide at the light coupling surface, wherein the light guide can be brought into an end position on the printed circuit board, in which end position the light coupling surface is oriented in a fixed orientation orthogonal to the main emission direction and at a fixed distance along the main emission direction with respect to the light source, a positioning device configured to determine the orientation of the light coupling surface with respect to the light source along the main emission direction of the light source and in a normal plane to the main emission direction,wherein the positioning device for aligning the light coupling surface in the normal plane has at least a first pair of positioning means, which comprises a projection extending parallel to the main emission direction and an opening corresponding to the projection, and wherein the positioning device for aligning the light coupling surface along the main emission direction of the light source has at least a second pair of positioning means, which comprises a stop and a stop surface corresponding to the stop, wherein the light guide has one means of the at least one first pair of positioning means and the at least one second pair of positioning means, and the circuit board has the remaining means of the at least one first pair of positioning means and the at least one second pair of positioning means,and wherein the light guide can be brought into the end position on the circuit board with respect to the at least one light source by inserting the projection of the at least one first pair of positioning means into the corresponding opening of the at least one first pair of positioning means, wherein one stop of the at least one second pair of positioning means strikes the corresponding stop surface of the at least one second pair of positioning means upon reaching the end position, and a securing means which is designed to secure the light guide in the end position on the circuit board and to hold the light coupling surface in position with respect to the light source.

[0002] Furthermore, the invention relates to a motor vehicle headlight comprising at least one lighting device according to the invention.

[0003] EP 2 775 197 A1 discloses a prior art lighting device for motor vehicle headlights.

[0004] In conventional lighting devices, the light guide, whose light coupling surface is aligned with respect to a light source arranged on a circuit board, is not attached directly to the circuit board itself.

[0005] Due to rising temperatures during operation of the light source, the materials of the circuit board and the light guide or the light coupling surface, which is usually located in close proximity to the light source, expand due to thermal expansion.

[0006] However, this changes the distance between the light coupling surface of the light guide and the associated light source, which causes different lighting results, for example even the destruction of the light source.

[0007] It is an object of the invention to provide an improved lighting device.

[0008] This object is achieved with a lighting device mentioned at the outset in that the securing means is designed as a spring-elastic U-shaped clamp, wherein the clamp is detachably arranged on the light guide and the circuit board and thereby engages around the light guide and the circuit board and presses them against each other.

[0009] By attaching the light guide directly to the circuit board, the distance between the light source and the light coupling surface of the light guide remains constant. This compensates for the expansion of the overall system.

[0010] The term "main radiation direction" is understood to mean the direction in which at least one light source emits the strongest or most light due to its directivity.

[0011] Preferably, the light coupling surface of the optical fiber lies in a normal plane to the main emission direction.

[0012] It can be provided that the corresponding means of the at least one first pair of positioning means, which means is arranged on the light guide, is manufactured in one piece with the light guide.

[0013] For example, the light guide is manufactured using an injection molding process.

[0014] It can be provided that the corresponding means of the at least one second pair of positioning means, which means is arranged on the light guide, is manufactured in one piece with the light guide.

[0015] It can be provided that the positioning device has at least two, preferably exactly two, first pairs of positioning means.

[0016] This establishes a more precise position in a plane normal to the main radiation direction of the light source. For example, the projections can be designed as cylindrical pins. However, if a single such pin is present—inserted into the designated opening—the circuit board or light guide can still be rotated around the cylindrical pin, which is undesirable.

[0017] It can be provided that the projection of the at least one first pair of positioning means is arranged on the light guide and the opening of the at least one first pair of positioning means is arranged on the circuit board.

[0018] This allows for screwless attachment of the light guide to the circuit board. This allows the circuit board to accommodate thermal expansion, and the distance between the light source and the light coupling surface can be kept constant.

[0019] The clamping force caused by the clamping means, which presses the circuit board and the light guide against each other, must be greater than the force caused by an expansion of the material of the light guide and the circuit board, caused by an increase in temperature, for example due to the operation of the light source, of the aforementioned components.

[0020] It can be provided that the positioning device has at least two, preferably exactly two, second pairs of positioning means.

[0021] It can be provided that the stop of the second pair of positioning means is arranged on the optical fiber and the stop surface of the second pair of positioning means is arranged on the circuit board.

[0022] It can be provided that the projection engages positively in the corresponding opening.

[0023] It can be provided that the projection penetrates the circuit board in the end position of the light guide on the circuit board.

[0024] It can be provided that the at least one light source is designed as an LED.

[0025] Preferably, in the case where two or more light-emitting diodes (LEDs) are provided, each light-emitting diode can be controlled independently of the other light-emitting diodes.

[0026] Each LED can thus be switched on and off independently of the other LEDs of a light source, and preferably when dimmable

[0027] LEDs can also be dimmed independently of the other LEDs in the light source.

[0028] The object is also achieved with a motor vehicle headlight which comprises at least one lighting device according to the invention.

[0029] The invention is explained in more detail below with reference to exemplary drawings. Fig. 1 an exemplary lighting device in a side view with a light guide, which has an end designed as a light coupling surface, and a circuit board on which a light source is arranged, in a non-assembled state of the lighting device, Fig. 2 the lighting device Fig. 1 , with the light guide in an end position on the circuit board, Fig. 3 the lighting device Fig. 2 , wherein the light guide located in the end position on the circuit board and the circuit board are secured by means of a securing means which is designed as a clamping means or clamp, Fig. 4 a perspective view of the assembled lighting device from Fig. 1 , and Fig. 5another perspective rear view of the assembled lighting device from Fig. 1 .

[0030] Fig. 1 shows an exemplary lighting device 10 for a motor vehicle headlight, wherein the lighting device 10 a circuit board 100, having a light source 110, which with the circuit board 100 and is designed to emit light in a main beam direction X to emit, and a light guide 200 wherein the light guide 200 a light coupling surface 210 has a developed end.

[0031] The term "main radiation direction" refers to the direction in which the light source 110, in this case an LED, emits the strongest or most light due to its directivity.

[0032] The light guide 200 is for guiding light from the light source 110,which in this example is designed as an LED, which light at the light coupling surface 210 into the light guide 200 can be coupled.

[0033] Furthermore, the light guide 200 into a final position P1 on the circuit board 100 can be brought, in which end position P1 the light coupling surface 210 in a fixed orientation orthogonal to the main radiation direction X and at a specified distance d along the main radiation direction X regarding the light source 110 oriented.

[0034] Fig. 1 shows the lighting device 10 in a not yet assembled state or not in the end position of the light guide 200 on the circuit board 100.

[0035] The lighting device 10 further comprises a positioning device 300,which is set up to adjust the orientation of the light coupling surface 210 regarding the light source 110 along the main radiation direction X the light source 110 and in a normal plane of the main radiation direction X to be determined, whereby the positioning device 300 for aligning the light coupling surface 210 in the normal plane two first pairs of positioning means 310 which each has a projection 311, which is parallel to the main radiation direction X extends, and one to the projection 311 corresponding opening 312 include, where in Fig. 1 Due to the side view shown, only a first positioning pair is visible. Fig. 5 shows the two of the lighting device 10 included two initial positioning pairs 310.

[0036] For alignment of the light coupling surface210 along the main radiation direction X the light source 110 includes the positioning device 300 two second pairs of positioning devices 320, which each have a stop 321 and one to the attack 321 corresponding stop surface 322 include.

[0037] In the example shown, the light guide comprises 200 the projections 311 the first two pairs of positioning devices 310 and the attacks 321 the two second pairs of positioning devices 320, where the circuit board 100 the remaining means of the first two pairs of positioning means 310 and the two second pairs of positioning means 320 The means of the first positioning pairs 310 are integral with the light guide 200 manufactured, for example by means of an injection molding process.

[0038] By inserting the projections 311 the first pairs of positioning devices 310 into the corresponding opening 312 is the light guide 200 to the end position P1 on the circuit board 100 with respect to at least one light source 110 can be brought, whereby the stops 321 the second pair of positioning devices 320 when the end position is reached P1 on the corresponding stop surfaces 322 strike, as in Fig. 2 shown. The projections engage 311 form-fitting in corresponding openings 312 and enforce in the final position P1 the circuit board 100 complete.

[0039] Furthermore, the lighting device comprises a securing means 400, which in the example shown is designed as a clamping means or clamp, wherein the securing means 400 detachable from the light guide200 and the circuit board 100 is arranged, and wherein the securing means 400 is set up to connect the light guide 200 in the end position P1 on the circuit board 100 to secure and the light coupling surface 210 in relation to the light source 110 to hold in position as in Fig. 3 is shown, where Fig. 3 among other things, an assembled state of the lighting device 10 shows.

[0040] It is important to ensure that the clamping device 400 caused clamping force, which the circuit board 100 and the light guide 200 against each other must be greater than the force caused by an expansion of the material of the light guide 200 and the circuit board 100 is caused by an increase in temperature of the components mentioned, for example by the operation of the light source 110.

[0041] Fig. 4 and Fig. 5 each show perspective views of the mounted lighting device 10. LIST OF REFERENCE SYMBOLS

[0042] Lighting device 10 circuit board 100 light source 110 light guide 200 End 201 Light coupling surface 210 Positioning device 300 First pair of positioning devices 310 projection 311 opening 312 Second pair of positioning devices 320 stop 321 Stop surface 322 Main radiation direction X End position P1 Distance d

Claims

1. Lighting device (10) for a motor vehicle headlamp, the lighting device (10) comprising - a printed circuit board (100), having at least one light source (110) which is connected to the printed circuit board (100) and is set up to emit light in a main radiation direction (X), - a light guide (200), having an end (201) which is designed as a light coupling surface (210), the light guide (200) being assigned to the at least one light source (110) for guiding light, which light can be coupled into the light guide (200) at the light coupling surface (210), wherein the light guide (200) can be brought into an end position (P1) on the printed circuit board (100), in which end position (P1) the light coupling surface (210) is oriented in a fixed orientation orthogonal to the main radiation direction (X) and at a fixed distance (d) along the main radiation direction (X) with respect to the light source (110), - a positioning device (300) which is set up to determine the alignment of the light coupling surface (210) with respect to the light source (110) along the main radiation direction (X) of the light source (110) and in a normal plane of the main radiation direction (X), wherein the positioning device (300) has at least a first pair of positioning means (310) for aligning the light coupling surface (210) in the normal plane, which comprises a projection (311), which extends parallel to the main radiation direction (X), and an opening (312) corresponding to the projection (311), and wherein the positioning device (300) for aligning the light coupling surface (210) along the main radiation direction (X) of the light source (110) has at least a second pair of positioning means (320), which comprises a stop (321) and a stop surface (322) corresponding to the stop (321), wherein the optical fiber (200) comprises a respective one of the at least one first pair of positioning means (310) and the at least one second pair of positioning means (320), and the printed circuit board (100) comprises the remaining one of the at least one first pair of positioning means (310) and the at least one second pair of positioning means (320), and wherein the light guide (200) can be brought into the end position (P1) on the printed circuit board (100) with respect to the at least one light source (110) by inserting the projection (311) of the at least one first pair of positioning means (310) into the corresponding opening (312) of the at least one first pair of positioning means (310), wherein the one stop (321) of the at least one second pair of positioning means (320) strikes against the corresponding stop surface (322) of the at least one second pair of positioning means (320) when the end position (P1) is reached, and - a securing means (400) which is set up to secure the light guide (200) in the end position (P1) on the printed circuit board (100) and to hold the light coupling surface (210) in position with respect to the light source (110), characterized in that the securing means (400) is designed as a spring-elastic U-shaped clamp, the clamp being detachably arranged on the light guide (200) and the printed circuit board (100) and thereby embracing the light guide (200) and the printed circuit board (100) and pressing them against each other.

2. Lighting device according to claim 1, characterized in that the corresponding means of the at least one first pair of positioning means (310), which means is arranged on the light guide (200), is manufactured in one piece with the light guide (200).

3. Lighting device according to claim 1 or 2, characterized in that the corresponding means of the at least one second pair of positioning means (320), which means is arranged on the light guide (200), is produced integrally with the light guide (200).

4. Lighting device according to one of claims 1 to 3, characterized in that the positioning device (300) has at least two, preferably exactly two, first pairs of positioning means (310).

5. Lighting device according to one of claims 1 to 4, characterized in that the projection (311) of the at least one first pair of positioning means (310) is arranged on the light guide (200) and the opening (312) of the at least one first pair of positioning means (310) is arranged on the printed circuit board (100).

6. Lighting device according to one of claims 1 to 5, characterized in that the positioning device (300) comprises at least two, preferably exactly two, second pairs of positioning means (320).

7. Lighting device according to one of claims 1 to 6, characterized in that the stop (321) of the at least one second pair of positioning means (320) is arranged on the light guide (200) and the stop surface (322) of the at least one second pair of positioning means (320) is arranged on the printed circuit board (100).

8. Lighting device according to one of claims 1 to 7, characterized in that the projection (311) engages positively in the opening (312) corresponding thereto.

9. Lighting device according to one of claims 1 to 8, characterized in that the projection (311) passes through the printed circuit board (100) in the end position (P1) of the light guide (200) on the printed circuit board (100).

10. Lighting device according to one of claims 1 to 9, characterized in that the at least one light source (110) is designed as an LED.

11. Motor vehicle headlamp, comprising at least one lighting device (10) according to any one of claims 1 to 10.