White light source based on nonlinear-optical processes

• US 20030006382A1
• Filed: 07/01/2002
• Published: 01/09/2003
• Est. Priority Date: 12/30/1999
• Status: Active Grant

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Muller, Rudiger, Spath, Werner
• Granted Patent: US 7,177,069 B2
• Time in Patent Office: Days
• US Class Current: 250/495.1
• CPC Class Codes: G02F 1/3532 Arrangements of plural nonlinear devices for generating multi-colour light beams, e.g. arrangements of SHG, SFG, OPO devices for generating RGB light beams
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

A white light source has a light emission device, in particular an IR laser diode, whose emitted radiation beam is converted, in a nonlinear-optical element and a conversion element, into a radiation beam with wavelengths λ₁, . . . λ_n which can be perceived as white light and can have a higher power rating.

Claims

1. A white light source, comprising:

a light emission device for emitting a radiation beam with at least one radiation frequency in one of a red spectral region and an infrared spectral region;

a nonlinear-optical element disposed downstream of said light emission device and into said nonlinear-optical element the radiation beam is coupled and converted into a frequency-mixed radiation beam at least partially by generation of at least one mixed frequency by at least one of frequency mixing, frequency doubling, summation frequency formation, and difference frequency formation; and

a conversion element disposed downstream of said nonlinear-optical element and into said conversion element the frequency-mixed radiation beam is coupled and converted at least partially into light radiation of one of longer wavelengths and shorter wavelengths in such a way that an emission spectrum of the radiation beam radiated by said conversion element has mutually complementarily colored spectral regions.

2. The white light source according to claim 1, wherein:

said nonlinear-optical element is configured in such a way that said nonlinear-optical element acts as a frequency doubler for an individual radiation frequency; and

said conversion element is a luminescence conversion element.

3. The white light source according to claim 2, wherein said luminescence conversion element is selected from the group consisting of an organic dye conversion element, an inorganic luminescent material conversion element, and a semiconductor conversion element.

4. The white light source according to claim 1, wherein:

said nonlinear-optical element is an optical-parametric oscillator; and

said conversion element is a second nonlinear-optical element which is capable of frequency doubling and summation frequency generation.

5. The white light source according to claim 1, wherein said light emission device is a solid state laser.

6. The white light source according to claim 5, wherein said solid-state laser is selected from the group consisting of edge-emitting laser diodes and vertical resonator laser diodes made of a material selected from the group consisting of GaAlAs, InGaAls, InGaAs and InGaAlP.

7. The white light source according to claim 5, wherein said solid-state laser is an Nd:

YAG laser.

8. The white light source according to claim 1, wherein said light emission device can be used for a pulsed operation.

9. The white light source according to claim 1, wherein said nonlinear-optical element has a material selected from the group consisting of KH₂PO₄, KNbO₃, BaNaNbO₁₅, LiIO₃, KTiOPO₄ (KTP), LiNbO₃, LiB₃O₅, and β

-BaB₂O₄.

10. The white light source according to claim 1, further comprising a common substrate, and said light emission device is one of a plurality of light emission devices disposed on said common substrate.

11. The white light source according to claim 10, wherein said light emission devices are vertical resonator laser diodes formed on said common substrate being a common semiconductor substrate.

12. The white light source according to claim 10, wherein said light emission devices emit radiation beams that pass through a respective location of said nonlinear-optical element.

13. The white light source according to claim 12, wherein said conversion element is applied directly on a surface of said nonlinear-optical element which is remote from said light emission devices.

14. The white light source according to claim 3, wherein said inorganic luminescent material conversion element uses phosphor.

15. The white light source according to claim 1, wherein:

said nonlinear-optical element is configured in such a way that said nonlinear-optical element generates a summation frequency from a plurality of different radiation frequencies of said light emission device; and

said conversion element is a luminescence conversion element.

17. The white light source according to claim 16, wherein:

said nonlinear-optical element is configured in such a way that said nonlinear-optical element acts as a frequency doubler for an individual radiation frequency; and

said conversion element is a luminescence conversion element.

18. The white light source according to claim 17, wherein said luminescence conversion element is selected from the group consisting of an organic dye conversion element, an inorganic luminescent material conversion element, and a semiconductor conversion element.

19. The white light source according to claim 16, wherein:

said nonlinear-optical element is an optical-parametric oscillator; and

said conversion element is a second nonlinear-optical element which is capable of frequency doubling and summation frequency generation.

20. The white light source according to claim 16, wherein said light emission device is a solid state laser.

21. The white light source according to claim 20, wherein said solid-state laser is selected from the group consisting of edge-emitting laser diodes and vertical resonator laser diodes made of a material selected from the group consisting of GaAlAs, InGaAls, InGaAs and InGaAlP.

22. The white light source according to claim 20, wherein said solid-state laser is an Nd:

YAG laser.

23. The white light source according to claim 16, wherein said light emission device can be used for a pulsed operation.

24. The white light source according to claim 16, wherein said nonlinear-optical element has a material selected from the group consisting of KH₂PO₄, KNbO₃, BaNaNbO₁₅, LiIO₃, KTiOPO₄ (KTP), LiNbO₃, LiB₃O₅ and β

-BaB₂O₄.

25. The white light source according to claim 16, further comprising a common substrate, and said light emission device is one of a plurality of light emission devices disposed on said common substrate.

26. The white light source according to claim 25, wherein said light emission devices are vertical resonator laser diodes formed on said common substrate being a common semiconductor substrate.

27. The white light source according to claim 25, wherein said light emission devices emit radiation beams that pass through a respective location of said nonlinear-optical element.

28. The white light source according to claim 27, wherein said conversion element is applied directly on a surface of said nonlinear-optical element which is remote from said light emission devices.

29. The white light source according to claim 18, wherein said inorganic luminescent material conversion element uses phosphor.

30. The white light source according to claim 16, wherein:

said nonlinear-optical element is configured in such a way that said nonlinear-optical element generates a summation frequency from a plurality of different radiation frequencies of said light emission device; and

said conversion element is a luminescence conversion element.

16. A white light source, comprising:

a light emission device for emitting a radiation beam with at least one radiation frequency in one of a red spectral region and an infrared spectral region;

a nonlinear-optical element disposed downstream of said light emission device and into said nonlinear-optical element the radiation beam is coupled and converted into a frequency-mixed radiation beam at least partially by generation of at least one mixed frequency by at least one of frequency mixing, frequency doubling, summation frequency formation, and difference frequency formation; and

a conversion element disposed downstream of said nonlinear-optical element and into said conversion element the frequency-mixed radiation beam is coupled and converted at least partially into light radiation of one of longer wavelengths and shorter wavelengths in such a way that an emission spectrum of the radiation beam radiated by said conversion element has spectral components in a red, green and blue spectral region.