Light emitting device

• US 20070189352A1
• Filed: 02/06/2007
• Published: 08/16/2007
• Est. Priority Date: 02/14/2006
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Sugiyama, Takafumi, Hama, Atsutomo, Kishimoto, Tomohisa, Nagahama, Shinichi
• Granted Patent: US 8,908,740 B2
• Time in Patent Office: Days
• US Class Current: 372/71
• CPC Class Codes: A61B 1/0653 with wavelength conversion
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7738 with alkaline earth metals
• CPC Class Codes: C09K 11/7741 Sulfates
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/7789 Oxysulfides

Abstract

A light emitting device, comprises: a light source that emits excitation light; a light guide that propagates the excitation light, and in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding); a wavelength conversion member that absorbs the excitation light propagated by the light guide and converts the wavelength thereof, and releases light of a predetermined wavelength band; and a shielding member that blocks the wavelength of at least part of the excitation light and the light emitted from the wavelength conversion member.

Claims

1. A light emitting device, comprising:

a light source that emits excitation light;

a light guide that propagates the excitation light, and in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a wavelength conversion member that absorbs the excitation light propagated by the light guide and converts the wavelength thereof, and releases light of a predetermined wavelength band; and

a shielding member that blocks the wavelength of at least part of the excitation light and the light emitted from the wavelength conversion member.

2. The light emitting device according to claim 1, wherein the shielding member is in the form of a lens.

3. The light emitting device according to claim 2, wherein the shielding member includes a diffusion member.

4. The light emitting device according to claim 1, comprising a reflection member that reflects at least part of the excitation light and the light emitted from the wavelength conversion member.

5. The light emitting device according to claim 4, wherein the wavelength conversion member is made up of two or more layers, and

the reflection member is sandwiched between the layers of the wavelength conversion member.

6. The light emitting device according to claim 4, wherein the reflection member reflects the excitation light.

7. The light emitting device according to claim 6, wherein the reflection member reflects light with a shorter wavelength than that near the emission peak wavelength of the wavelength conversion member.

8. The light emitting device according to claim 7, wherein the reflection member reflects light with a wavelength of about 420 nm or less.

9. The light emitting device according to claim 1, comprising a light guide end member at the end of the emission side of the light guide, wherein a reflective film that reflects light of a predetermined wavelength band is formed at the end face of this light guide end member.

10. A light emitting device, comprising:

at least one first light source that emits light whose emission peak wavelength is in a wavelength band of 400 to 500 nm;

at least one second light source that emits light whose emission peak wavelength is in a wavelength band of 600 to 700 nm;

a first light guide having at least one optical fiber for propagating the light emitted by the first light source, in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a second light guide having at least one optical fiber for propagating the light emitted by the second light source, in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a wavelength conversion member that is provided to just the end on the emission side of the first light guide, or to both the end on the emission side of the first light guide and the end on the emission side of the second light guide, absorbs the light propagated by the first light guide and converts the wavelength thereof, and releases light having an emission peak wavelength in a wavelength band of 450 to 650 nm.

11. The light emitting device according to claim 10, comprising a multi-fiber light guide end member at the ends on the emission side of the first light guide and the second light guide.

12. The light emitting device according to claim 10, comprising single-fiber first and second light guide end members at the respective ends on the emission side of the first light guide and the second light guide.

13. A light emitting device, comprising:

at least one first light source that emits light whose emission peak wavelength is in a wavelength band of 400 to 500 nm;

at least one second light source that emits light whose emission peak wavelength is in a wavelength band of 600 to 700 nm;

at least one third light source that emits light whose emission peak wavelength is in a wavelength band of 300 to 400 nm;

a first light guide having at least one optical fiber for propagating the light emitted by the first light source, in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a second light guide having at least one optical fiber for propagating the light emitted by the second light source, in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a third light guide having at least one optical fiber for propagating the light emitted by the third light source, in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding);

a wavelength conversion member that is provided to just the end on the emission side of the third light guide, or to both the end on the emission side of the first light guide and the end on the emission side of the third light guide, or to the end on the emission side of the first light guide, the end on the emission side of the second light guide, and the end on the emission side of the third light guide, absorbs the light propagated by the third light guide and converts the wavelength thereof, and releases light having an emission peak wavelength in a wavelength band of 450 to 650 nm.

14. The light emitting device according to claim 13, comprising a multi-fiber light guide end member at the ends on the emission side of the first light guide, the second light guide, and the third light guide.

15. The light emitting device according to claim 13, comprising single-fiber first, second, and third light guide end members at the respective ends on the emission side of the first light guide, the second light guide, and the third light guide.