Light-emitting device and illuminator

• US 20040188689A1
• Filed: 03/24/2004
• Published: 09/30/2004
• Est. Priority Date: 03/27/2003
• Status: Active Grant

• Current Assignee: LEDVANCE GmbH (MLS Co. Ltd.)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Hata, Masayuki, Shono, Masayuki
• Granted Patent: US 7,078,735 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light-emitting device, having high light extraction efficiency, capable of obtaining diffused light is obtained. This light-emitting device comprises a light-emitting diode, a portion, formed on a plane substantially parallel to a light-emitting surface of the light-emitting diode, having a dielectric constant periodically modulated with respect to the in-plane direction of the plane substantially parallel to the light-emitting surface and a member provided on the side of the light-emitting surface of the light-emitting diode for diffusing light emitted from the light-emitting diode.

Claims

1. A light-emitting device comprising:

a light-emitting diode;

a portion, formed on a plane substantially parallel to a light-emitting surface of said light-emitting diode, having a dielectric constant periodically modulated with respect to the in-plane direction of said plane substantially parallel to said light-emitting surface; and

a member provided on the side of said light-emitting surface of said light-emitting diode for diffusing light emitted from said light-emitting diode.

2. The light-emitting device according to claim 1, wherein

said portion having said periodically modulated dielectric constant is constituted by periodically arranging materials having different dielectric constants.

3. The light-emitting device according to claim 1, wherein

said portion having said periodically modulated dielectric constant consists of a photonic crystal.

4. The light-emitting device according to claim 1, wherein

said member diffusing emitted said light is conductive.

5. The light-emitting device according to claim 4, wherein

said conductive member diffusing said emitted light is formed to be in contact with a portion of said light-emitting diode provided on the light-emitting side.

6. The light-emitting device according to claim 4, wherein

said conductive member diffusing said emitted light consists of at least one material selected from a group consisting of n-type SiC, n-type AlN and p-type diamond.

7. The light-emitting device according to claim 1, wherein

said member diffusing emitted said light includes a lens.

8. The light-emitting device according to claim 7, wherein

said member diffusing said emitted light includes a concave lens.

9. The light-emitting device according to claim 8, wherein

said concave lens includes a plano-concave lens having a flat first surface and a concave second surface.

10. The light-emitting device according to claim 1, wherein

said member diffusing emitted said light includes a convex mirror.

11. The light-emitting device according to claim 1, wherein

said member diffusing emitted said light includes a translucent member dispersively containing a light diffusing agent consisting of substantially transparent particulates.

12. The light-emitting device according to claim 1, wherein

said member diffusing emitted said light includes a translucent member having fine corrugation at least either on the front surface or on the back surface.

13. The light-emitting device according to claim 12, wherein

the interval between adjacent projecting portions in said fine corrugation is at least about 200 nm and not more than about 2000 nm.

14. The light-emitting device according to claim 12, wherein

the interval between adjacent projecting portions in said fine corrugation is at least about 2 μ

m and not more than about 100 μ

m.

15. The light-emitting device according to claim 1, further comprising a fluorescent body provided between said light-emitting surface and said member diffusing emitted said light.

16. The light-emitting device according to claim 1, wherein

said light-emitting diode includes an emission layer, and

said emission layer consists of a nitride-based semiconductor.

17. The light-emitting device according to claim 1, wherein

a plurality of said light-emitting diodes are arranged in the form of a matrix in plane.

18. The light-emitting device according to claim 17, wherein

said member diffusing emitted said light includes a lens, and

a plurality of said lenses are arranged in the form of a matrix in plane.

19. A light-emitting device comprising:

a light-emitting diode;

a portion, formed on a plane substantially parallel to a light-emitting surface of said light-emitting diode, having a dielectric constant periodically modulated with respect to the in-plane direction of said plane substantially parallel to said light-emitting surface; and

means provided on the side of said light-emitting surface of said light-emitting diode for diffusing light emitted from said light-emitting diode.

20. An illuminator comprising a light-emitting device including:

a light-emitting diode;

a portion, formed on a plane substantially parallel to a light-emitting surface of said light-emitting diode, having a dielectric constant periodically modulated with respect to the in-plane direction of said plane substantially parallel to said light-emitting surface; and

a member provided on the side of said light-emitting surface of said light-emitting diode for diffusing light emitted from said light-emitting diode.

21. The illuminator according to claim 20, further comprising a fluorescent body arranged at a prescribed interval from said light-emitting device for converting light emitted from said light-emitting device to white light.

22. The illuminator according to claim 21, wherein

said fluorescent body is formed by mixing fluorescent materials having a plurality of colors with each other.

23. The illuminator according to claim 20, wherein

a plurality of said light-emitting diodes constituting said light-emitting device are arranged in the form of a matrix in plane.

24. The illuminator according to claim 23, wherein

said member diffusing emitted said light includes a lens, and

a plurality of said lenses are arranged in the form of a matrix in plane.