Light emitting device

• US 8,908,740 B2
• Filed: 02/06/2007
• Issued: 12/09/2014
• Est. Priority Date: 02/14/2006
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Nagahama, Shinichi, Hama, Atsutomo, Kishimoto, Tomohisa, Sugiyama, Takafumi
• Primary Examiner(s): VAN ROY, TOD THOMAS
• Application Number:
  US11/702,598
• Publication Number:
  US 20070189352A1
• Time in Patent Office: 2,863 Days
• Field of Search: 372/21, 372/108, 362/574, 362/84, 362/217.08, 362/260, 606/15, 606/16, 607/93
• US Class Current: 372/108
• 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 of a cross section is higher than the refractive index of the peripheral part;

a light guide end member supporting an end of an emission side of the light guide and covering an outer circumference of the light guide;

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

a shielding member that blocks the wavelength of at least part of the excitation light and the light emitted from the wavelength conversion member, the shielding member being disposed on a first side of the wavelength conversion member and the light guide being disposed on a second side of the wavelength conversion member that is different from the first side; and

a reflection member that reflects at least part of the excitation light and the light emitted from the wavelength conversion member, the reflection member including a reflective film that reflects light of a predetermined wavelength band with the reflective film being formed at an end face of the light guide end member, wherein

the wavelength conversion member is coupled to a tip end of the light guide on the second side of the wavelength conversion member with the reflection member being sandwiched between the light guide and the wavelength conversion member.

2. The light emitting device according to claim 1, wherein the reflection member reflects light with a shorter wavelength than that near the emission peak wavelength of the wavelength conversion member.

3. The light emitting device according to claim 2, wherein the reflection member reflects light with a wavelength of about 420 nm or less.

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

the reflection member includes an excitation light reflecting member arranged at least on a wavelength converted light emission region of the wavelength converting member.

5. The light emitting device according to claim 1, wherein

the shielding member is attached to an emission side of the reflection member.

6. The light emitting device according to claim 1, wherein

at least one of the shielding member and the reflection member is in contact with the wavelength conversion member.

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

the wavelength conversion member includes a resin layer containing the fluorescent substance.

8. The light emitting device according to claim 1, wherein

the shielding member is configured and arranged to allow only light having a prescribed wavelength to pass through.

9. 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 of a cross section is higher than the refractive index of the peripheral part;

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

a shielding member disposed fully downstream of an end of an emission side of the light guide with respect to a propagation direction of the light, and that blocks the wavelength of at least part of the excitation light and the light emitted from the wavelength conversion member; and

a reflection member that reflects at least part of the excitation light and the light emitted from the wavelength conversion member,

wherein the shielding member is in the form of a lens.

10. The light emitting device according to claim 9, wherein the shielding member includes a diffusion member.

11. The light emitting device according to claim 9, wherein

the reflection member includes an excitation light reflecting member arranged at least on a wavelength converted light emission region of the wavelength converting member.

12. The light emitting device according to claim 9, wherein

the reflection member includes a wavelength-converted light reflecting member arranged at least on an excitation light incidence region of the wavelength converting member.

13. The light emitting device according to claim 9, wherein

the shielding member is attached to an emission side of the reflection member.

14. The light emitting device according to claim 9, wherein

at least one of the shielding member and the reflection member is in contact with the wavelength conversion member.

15. The light emitting device according to claim 9, wherein

the wavelength conversion member includes a resin layer containing the fluorescent substance.

16. The light emitting device according to claim 9, wherein

the shielding member is configured and arranged to allow only light having a prescribed wavelength to pass through.

17. 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 of a cross section is higher than the refractive index of the peripheral part;

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

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

a reflection member that reflects at least part of the excitation light and the light emitted from the wavelength conversion member,

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.