Vehicle headlight

Patent metadata

Field	Value
Publication number	US-9335016-B2
Application number	US-201414217982-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Mar 18, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A vehicle headlight can be configured such that the size of the vehicle headlight which includes a semiconductor laser element employed as a light source is reduced. The vehicle headlight can includes: a projection lens disposed on an optical axis extending in a front-to-rear direction of a vehicle body; a light-emitting device including a semiconductor laser element configured to emit a laser beam and a light-transmitting member configured to absorb and convert the wavelength of at least part of the laser beam from the semiconductor laser element; and a first reflection surface configured to reflect the light from the light-emitting device so as to transmit and project forward the resulting light through the projection lens. The vehicle headlight can further include: a light detection unit configured to detect a light beam of a specific color, the light detection unit being disposed between the projection lens and the light-emitting device and below the optical axis; a second reflection surface configured to reflect the light beam from the light-emitting device toward the light detection unit, the second reflection surface being disposed ahead of the front end of the first reflection surface; and a control unit configured to control the semiconductor laser element in accordance with a detection result provided by the light detection unit so that the semiconductor laser element does not emit the laser beam.

First claim

What is claimed is:

1. A vehicle headlight comprising:
a projection lens disposed on an optical axis extending in a front-to-rear direction of a vehicle body;
a light-emitting device including a semiconductor laser element configured to emit a laser beam and a light-transmitting member configured to absorb and convert the wavelength of at least part of the laser beam from the semiconductor laser element;
a first reflection surface configured to reflect the light from the light-emitting device so as to transmit and project forward the resulting light through the projection lens;
a light detection unit configured to detect a light beam of a specific color, the light detection unit being disposed between the projection lens and the light-emitting device and below the optical axis;
a second reflection surface configured to reflect the light beam from the light-emitting device toward the light detection unit, the second reflection surface being disposed ahead of the front end of the first reflection surface; and
a control unit configured to control the semiconductor laser element in accordance with a detection result provided by the light detection unit so that the semiconductor laser element does not emit the laser beam.

2. The vehicle headlight according to claim 1 , wherein the light of a specific color is a light beam that is wavelength-converted by the light-transmitting member, and
the control unit controls the semiconductor laser element so as not to emit a laser beam while the semiconductor laser element is emitting the laser beam and when the light detection unit does not detect light that has been wavelength-converted by the light-transmitting member.

3. The vehicle headlight according to claim 2 , comprising a light shielding member disposed between the projection lens and the light-emitting device, the light shielding member being configured to block a light beam travelling upward among those beams from the light-emitting device to be projected forward through the projection lens.

4. The vehicle headlight according to claim 3 , comprising a second light shielding member disposed between the second reflection surface and the light detection unit, and a pin hole through which a reflected light beam from the second reflection surface passes can be formed in the second light shielding member.

5. The vehicle headlight according to claim 4 , wherein the second reflection surface is an ellipsoid of revolution having a first focus at or substantially near the light-transmitting member, and a second focus set inside the pin hole or at the vicinity thereof.

6. The vehicle headlight according to claim 2 , comprising a light shielding member disposed between the second reflection surface and the light detection unit, and a pin hole through which a reflected light beam from the second reflection surface passes can be formed in the light shielding member.

7. The vehicle headlight according to claim 6 , wherein the second reflection surface is an ellipsoid of revolution having a first focus at or substantially near the light-transmitting member, and a second focus set inside the pin hole or at the vicinity thereof.

8. The vehicle headlight according to claim 2 , wherein an area of the first reflection surface to be irradiated with a laser beam from the light-emitting device with the light-transmitting member having dropped off has a through hole formed to allow the laser beam to pass therethrough.

9. The vehicle headlight according to claim 2 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

10. The vehicle headlight according to claim 1 , comprising a light shielding member disposed between the projection lens and the light-emitting device, the light shielding member being configured to block a light beam travelling upward among those beams from the light-emitting device to be projected forward through the projection lens.

11. The vehicle headlight according to claim 10 , comprising a second light shielding member disposed between the second reflection surface and the light detection unit, and a pin hole through which a reflected light beam from the second reflection surface passes can be formed in the second light shielding member.

12. The vehicle headlight according to claim 11 , wherein the second reflection surface is an ellipsoid of revolution having a first focus at or substantially near the light-transmitting member, and a second focus set inside the pin hole or at the vicinity thereof.

13. The vehicle headlight according to claim 10 , wherein an area of the first reflection surface to be irradiated with a laser beam from the light-emitting device with the light-transmitting member having dropped off has a through hole formed to allow the laser beam to pass therethrough.

14. The vehicle headlight according to claim 10 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

15. The vehicle headlight according to claim 1 , comprising a light shielding member disposed between the second reflection surface and the light detection unit, and a pin hole through which a reflected light beam from the second reflection surface passes can be formed in the light shielding member.

16. The vehicle headlight according to claim 15 , wherein the second reflection surface is an ellipsoid of revolution having a first focus at or substantially near the light-transmitting member, and a second focus set inside the pin hole or at the vicinity thereof.

17. The vehicle headlight according to claim 16 , wherein an area of the first reflection surface to be irradiated with a laser beam from the light-emitting device with the light-transmitting member having dropped off has a through hole formed to allow the laser beam to pass therethrough.

18. The vehicle headlight according to claim 15 , wherein an area of the first reflection surface to be irradiated with a laser beam from the light-emitting device with the light-transmitting member having dropped off has a through hole formed to allow the laser beam to pass therethrough.

19. The vehicle headlight according to claim 15 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

20. The vehicle headlight according to claim 16 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

21. The vehicle headlight according to claim 1 , wherein an area of the first reflection surface to be irradiated with a laser beam from the light-emitting device with the light-transmitting member having dropped off has a through hole formed to allow the laser beam to pass therethrough.

22. The vehicle headlight according to claim 21 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

23. The vehicle headlight according to claim 1 , comprising an optical system configured to condense the laser beam from the semiconductor laser element so as to locally irradiate the light-transmitting member.

24. The vehicle headlight according to claim 23 , wherein the light-transmitting member include:
a diffusion layer ha

Assignees

• Stanley Electric Co Ltd

Inventors

• Nakazato Yoshiaki

Classifications

• B60Q1/0023

  the element being a sensor, e.g. distance sensor, camera · CPC title

• F21S41/338

  the reflector having surface portions added to its general concavity · CPC title

• F21S41/16

  Laser light sources · CPC title

• B60Q2300/146

  Abnormalities, e.g. fail-safe · CPC title

• F21S45/70

  Prevention of harmful light leakage · CPC title