Light-emitting device and illuminator
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.
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 μm and not more than about 100 μm.
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.