Light emitting device and illumination apparatus
A light emitting device includes a base on which a wiring conductor is formed from the top surface to the bottom surface or the side face; a light emitting chip mounted on the top surface of the base and electrically connected with the wiring conductor; a first light transmitting member which covers the light emitting chip; a second light transmitting member provided above the first light transmitting member to cover the first light transmitting member, the second light transmitting member being formed of a light transmitting material containing fluorescent materials for converting in wavelength the light emitted from the light emitting chip; and a third light transmitting member provided between the first and second light transmitting members, wherein the refractive index n 1 of the first light transmitting member, the refractive index n 2 of the second light transmitting member and the refractive index n 3 of the third light transmitting member satisfy the relation: n 3 <n 1 and n 3 <n 2 , thereby achieving higher light extraction efficiency, higher optical intensity of radiation, and higher axial luminosity and brightness.
1. A light emitting device comprising:
a base on which a wiring conductor is formed from the top surface to the bottom surface or the side face thereof; a light emitting chip mounted on the top surface of the base and electrically connected with the wiring conductor;
a first light transmitting member which covers the light emitting chip;
a second light transmitting member provided above the first light transmitting member to cover the first light transmitting member, the second light transmitting member being formed of a light transmitting material containing fluorescent materials for converting in wavelength the light emitted from the light emitting chip; and
a third light transmitting member provided between the first and second light transmitting members,
wherein the refractive index n 1 of the first light transmitting member, the refractive index n 2 of the second light transmitting member and the refractive index n 3 of the third light transmitting member satisfy the relation: n 3 <n 1 and n 3 <n 2 .
2. The light emitting device according to claim 1 , wherein the third light transmitting member is formed of a gaseous layer.
3. The light emitting device according to claim 1 , wherein a fourth light transmitting member having an refractive index n 4 is formed in contact with the lower face of the second light transmitting member, wherein the refractive indices n 2 and n 4 satisfy the relation: n 2 >n 4 .
4. The light emitting device according to claim 1 , wherein the first light transmitting member is made of silicone resin.
5. The light emitting device according to claim 1 , wherein the second light transmitting member is made of silicone resin containing fluorescent material.
6. The light emitting device according to claim 1 , wherein a reflective member is adhered onto the periphery of the base so as to enclose the light emitting chip, and the reflective member has an optically-reflective inner surface.
7. The light emitting device according to claim 1 , wherein the upper face of the first light transmitting member has a concave shape.
8. The light emitting device according to claim 1 , wherein the upper face of the first light transmitting member has a convex shape.
9. The light emitting device according to claim 1 , wherein the first light transmitting member is provided only on the upper face and the side face of the light emitting chip.
10. The light emitting device according to claim 1 , wherein the light emitting chip has a main peak of emission in a near-ultraviolet or ultraviolet range.
11. An illumination apparatus employing the light emitting device according to any one of claims 1 to 10 , as a light source.