Motor vehicle headlight element

• US 8,884,521 B2
• Filed: 03/12/2012
• Issued: 11/11/2014
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: OSRAM Licht AG (Ams-Osram AG)
• Original Assignee: OSRAM Licht AG (Ams-Osram AG)
• Inventors: Behr, Gerhard, Biebl, Alois, Engl, Moritz, Haas, Heinz, Hackenbuchner, Stefan, Helbig, Peter, Hofmann, Markus, Huber, Rainer, Reill, Joachim, Reiners, Thomas, Vollmer, Ralf, Hirschmann, Gnther
• Primary Examiner(s): Vo, Tuyet Thi
• Application Number:
  US13/417,516
• Publication Number:
  US 20120169232A1
• Time in Patent Office: 974 Days
• Field of Search: 315/247, 315/209.R, 315/224, 315/291, 315/307, 315/185.S, 315 49- 55
• US Class Current: 315/82
• CPC Class Codes: B60Q 1/0023 the element being a sensor, e.g. distance sensor, camera
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: B60Q 2300/054 Variable non-standard intensity, i.e. emission of various beam intensities different from standard intensities, e.g. continuous or stepped transitions of intensity
• CPC Class Codes: B60Q 2300/314 Ambient light
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 23/0442 activated by means of a sensor, e.g. motion or photodetectors
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: H05B 45/40 Details of LED load circuits

Abstract

A motor vehicle headlight element is specified which has at least one light-emitting diode and at least one control apparatus. The control apparatus is suitable for processing a signal which is dependent on a measurement variable and for applying a current, corresponding to the signal, to the light-emitting diode. The control apparatus and the light-emitting diode are arranged on a common mount.

Claims

1. Motor vehicle headlight element, comprising:

at least one light-emitting diode with at least one light-emitting diode chip;

a luminescence conversion material which follows the radiation output surface of the light-emitting diode chip or of at least one of the light-emitting diode chips, the luminescence conversion material is for wavelength conversion of at least a portion of the electromagnetic radiation emitted from the at least one light-emitting diode chip;

at least one light-emitting diode with at least one light-emitting diode chip which is for emission of radiation in the infrared spectral range;

at least one control apparatus, which is for processing a signal which is dependent on a measurement variable and for applying a current corresponding to the signal to the light-emitting diode,

wherein the control apparatus and the light-emitting diode are arranged on a common mount; and

wherein the motor vehicle headlight element is for emission of white light.

2. Motor vehicle headlight element according to claim 1, which comprises only one light-emitting diode.

3. Motor vehicle headlight element according to claim 1, further comprising a temperature sensor, wherein the control apparatus is suitable for application of the current to the light-emitting diode as a function of the signal from the temperature sensor;

wherein the temperature sensor is thermally coupled to the light-emitting diode; and

wherein the temperature sensor is arranged on the mount.

4. Motor vehicle headlight element according to claim 1, further comprising a photodetector,

wherein the control apparatus is suitable for application of the current to the light-emitting diode as a function of the signal from the photodetector;

wherein the photodetector is suitable for detection of the electromagnetic radiation which is emitted from the light-emitting diode; and

wherein the photodetector is arranged on the mount.

5. Motor vehicle headlight element according to claim 1, further comprising a photodetector,

wherein the control apparatus is suitable for application of the current to the light-emitting diode as a function of the signal from the photodetector;

wherein the photodetector is suitable for detecting an ambient brightness; and

wherein the photodetector is arranged outside the headlight.

6. Motor vehicle headlight element according to claim 1, further comprising a pulse-width modulation circuit which is arranged on the mount,

wherein the pulse-width modulation circuit is suitable for dimming the light-emitting diode;

and

wherein the control apparatus is suitable for setting the duty cycle of the pulse-width modulation circuit.

7. Motor vehicle headlight element according to claim 1, further comprising a controllable voltage supply which is arranged on the mount,

wherein the light-emitting diode chips of the light-emitting diode are electrically connected in series;

and

wherein the voltage supply is suitable to provide a voltage between 1 and 5 V per light-emitting diode chip.

8. Motor vehicle headlight element according to claim 1, in which the light-emitting diode contains at least one thin-film light-emitting diode chip,

wherein a reflective layer or layer sequence is applied to or formed on a first main surface, which faces the mount face of a radiation-producing epitaxial layer sequence of the thin-film light-emitting diode chip;

wherein the epitaxial layer sequence has a thickness of at most 10 μ

m and wherein the epitaxial layer sequence contains at least one semiconductor layer with at least one surface which has a mixing structure, the mixing structure has a stochastic scattering behaviour.

9. Motor vehicle headlight element according to claim 1, wherein the control apparatus and the light-emitting diode are arranged on a same main side of the common mount.

10. Motor vehicle headlight element according to claim 1, further comprising a varistor and at least one connecting pin which is arranged on the mount, wherein the at least one connecting pin is connected in parallel with the varistor.

11. Motor vehicle headlight element according to claim 10, wherein the at least one varistor is connected in parallel with the light-emitting diode.

12. Motor vehicle headlight element according to claim 1, further comprising light-emitting diode optics,

wherein the light-emitting diode optics follow at least one of the light-emitting diode chips of the light-emitting diode;

and

wherein the light-emitting diode optics are suitable for reducing the divergence of the electromagnetic radiation emitted from said light-emitting diode chips.

13. Motor vehicle headlight element according to claim 12, wherein the light-emitting diode comprises a plurality of light-emitting diode chips which are suitable for emission of light in the blue spectral range;

and

wherein the light-emitting diode optics are a common optical element for all of the light-emitting diode chips.

14. Motor vehicle headlight element according to claim 12, wherein the light-emitting diode optics are a non-imaging optical concentrator;

and

wherein the light-emitting diode optics are formed partially or completely according to the type of at least one of the following optical elements;

compound parabolic concentrator;

compound ellyptic concentrator;

compound hyperbolic concentrator, truncated pyramid, truncated cone.

15. Motor vehicle headlight element according to claim 12, wherein the light-emitting diode optics comprise reflective side walls which are suitable for reflection of at least a portion of the electromagnetic radiation emitted from the light-emitting diode chips.

16. Motor vehicle headlight element according to claim 12, wherein at least a portion of the luminescence conversion material is included in the light-emitting diode optics.

17. Motor vehicle headlight element according to claim 12, wherein the luminescence conversion material is applied as a thin film to side walls of the light-emitting diode optics, said side walls are arranged downstream from the radiation output surface of the light-emitting diode chips.

18. Motor vehicle headlight element according to claim 12, wherein the light-emitting diode optics have a radiation inlet opening which is at most twice as large as the total radiation output area of the light-emitting diode chips which are associated with the light-emitting diode optics.