Light source

• US 7,837,371 B2
• Filed: 12/23/2008
• Issued: 11/23/2010
• Est. Priority Date: 04/29/2003
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Bogner, Georg, Grötsch, Stefan
• Primary Examiner(s): DZIERZYNSKI, EVAN P
• Application Number:
  US12/343,433
• Publication Number:
  US 20090109699A1
• Time in Patent Office: 700 Days
• Field of Search: 362/26, 362/616, 362/612, 362/606, 362/621, 362/554, 362/555, 362/556, 362/582, 362/293, 362/294, 362/231
• US Class Current: 362/555
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A light source, such as for a projection system, having a plurality of semiconductor chips and at least two different, electromagnetic-radiation-emitting chip types with different emission spectra, each semiconductor chip having a chip coupling-out area through which radiation is coupled out. Furthermore, the light source has a plurality of primary optical elements, each semiconductor chip being assigned a primary optical element, which in each case has a light input and a light output and reduces the divergence of at least part of the radiation emitted by the semiconductor chip during the operation thereof. The semiconductor chips with the primary optical elements are arranged in at least two groups that are spatially separate from one another, with the result that the groups emit separate light cones during operation of the semiconductor chips. The separate light cones of the groups are superposed by means of a secondary optical arrangement to form a common light cone.

Claims

1. A light source comprising:

a plurality of semiconductor chips and at least two different electromagnetic-radiation-emitting chip types having different emission spectra, each of said semiconductor chips having a chip coupling-out area through which the electromagnetic radiation is coupled out;

a plurality of primary optical elements, each of said semiconductor chips having a respective one of said primary optical elements corresponding thereto, which has a light input and a light output and reduces the divergence of at least part of the electromagnetic radiation emitted by the semiconductor chip during operation thereof, wherein the semiconductor chips with the respectively corresponding primary optical elements are arranged in at least two groups that are spatially separated from one another, such that the groups emit separate light cones during operation of the semiconductor chips, and

a secondary optical arrangement, wherein said secondary optical arrangement superposes the separate light cones of the groups to form a common light cone, and

wherein the light input has a light input area or a light input opening, which has a size that is less than or equal to two times the chip coupling-out area.

2. The light source according to claim 1, wherein the light input has a light input area or a light input opening, the size of which is less than or equal to 1.5 times the chip coupling-out area.

3. The light source according to claim 1, wherein each of the plurality of primary optical elements is an optical concentrator, the light input being the actual concentrator output, so that light passes through the concentrator in the opposite direction compared with the customary application of a concentrator for focusing and is thus not concentrated, but rather leaves the concentrator with reduced divergence through the light output.

4. The light source according to claim 3, wherein the optical concentrator has reflective sidewalls which at least partly have the form of at least one of a compound parabolic concentrator CPC a compound elliptic concentrator (CEC) and a compound hyperbolic concentrator (CH-C).

5. The light source according to claim 3, wherein the optical concentrator has side walls which connect the light input to the light output and are formed in such a way that direct connecting lines running on the side walls essentially run straight between the light input and the light output.

6. The light source according to claim 3, wherein the optical concentrator is a dielectric concentrator, a basic body of which is a solid body composed of a dielectric material with a suitable refractive index, so that light coupled in via the light input is reflected in basic body by total reflection at the lateral interface, coupling the light input to the light output, of the solid body to the surrounding medium.

7. The light source according to claim 6, wherein the light output is surface of the solid body which is curved as a lens.

8. The light source according to claim 7, wherein the light output has a curvature which compared with a spherical curvature decreases with increasing distance from an optical axis of the optical concentrator.

9. The light source according to claim 3, wherein the optical concentrator is arranged downstream of the semiconductor chip in the main radiating direction thereof, and in that there is a gap between the chip coupling-out area and the light input of the optical concentrator.

10. The light source according to claim 9, wherein the gap is substantially free of solid or viscous material.

11. The light source according to claim 1, wherein a plurality of primary optical elements are formed in one part with one another.

12. The light source according to claim 1, wherein the primary optical elements of at least one group are at least partly arranged in such a way that their light outputs adjoin one another without any gaps.

13. The light source according to claim 1, wherein an aperture angle of the separate light cones is between 0 and 40°

, the limits being included.

14. The light source according to claim 1, wherein an aperture angle of the separate light cones is between 0 and 20°

, the limits being included.

15. A light source comprising:

a plurality of semiconductor chips and at least two different electromagnetic-radiation-emitting chip types having different emission spectra, each of said semiconductor chips having a chip coupling-out area through which the electromagnetic radiation is coupled out;

a plurality of primary optical elements, each of said semiconductor chips having a respective one of said primary optical elements corresponding thereto, which has a light input and a light output and reduces the divergence of at least part of the electromagnetic radiation emitted by each of the semiconductor chips during operation thereof;

wherein each of the plurality of primary optical elements is an optical concentrator, the light input being the actual concentrator output, so that the light passes through the optical concentrator in the opposite direction compared with the customary application of a concentrator for focusing and is thereby not concentrated, but rather leaves the concentrator with reduced divergence through the light output;

wherein the optical concentrator has a quadrangular cross-sectional area in a region on the side of the light input, and a cross-sectional area in the form of a triangular, hexagonal, or octagonal cross-sectional area in a region on the side of the light output;

wherein the semiconductor chips with the respectively corresponding primary optical elements are arranged in two groups that are spatially separated from one another, such that the groups emit separate light cones during operation of the semiconductor chips; and

a secondary optical arrangement, wherein said secondary optical arrangement superposes the separate light cones of the groups to form a common light cone.

16. The light source according to claim 15, wherein the optical concentrator has reflective sidewalls which at least partly have the form of at least one of a compound parabolic concentrator (CPC), a compound elliptic concentrator (CEC) and a compound hyperbolic concentrator (CH-C).

17. The light source according to claim 15, wherein the optical concentrator has side walls which connect the light input to the light output and are formed in such a way that direct connecting lines running on the side walls essentially run straight between the light input and the light output.

18. The light source according to claim 15, wherein the optical concentrator is a dielectric concentrator, a basic body of which is a solid body composed of a dielectric material with a suitable refractive index, so that light coupled in via the light input is reflected in basic body by total reflection at the lateral interface, coupling the light input to the light output, of the solid body to the surrounding medium.

19. The light source according to claim 18, wherein the light output is surface of the solid body which is curved as a lens.

20. The light source according to claim 19, wherein the light output has a curvature which compared with a spherical curvature decreases with increasing distance from an optical axis of the optical concentrator.

21. The light source according to claim 15, wherein the optical concentrator is arranged downstream of the semiconductor chip in a main radiating direction thereof, and wherein there is a gap between the chip coupling-out area and the light input of the optical concentrator.

22. The light source according to claim 21, wherein the gap is substantially free of solid or viscous material.

23. The light source according to claim 15, wherein a plurality of primary optical elements are formed in one part with one another.

24. The light source according to claim 15, wherein the primary optical elements of at least one group are at least partly arranged in such a way that their light outputs adjoin one another without any gaps.

25. The light source according to claim 15, wherein an aperture angle of the separate light cones is between 0 and 40°

, the limits being included.

26. The light source according to claim 15, wherein an aperture angle of the separate light cones is between 0 and 20°

, the limits being included.