Vehicle lamp using emitting device for suppressing color tone difference according to illumination conditions

• US 7,501,749 B2
• Filed: 11/01/2005
• Issued: 03/10/2009
• Est. Priority Date: 11/04/2004
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Kuboyama, Osamu, Takeda, Hitoshi
• Primary Examiner(s): Williams; Joseph L
• Assistant Examiner(s): Breval; Elmito
• Application Number:
  US11/262,893
• Publication Number:
  US 20060091779A1
• Time in Patent Office: 1,225 Days
• Field of Search: 313498-512, 252/301.4 R, 252/301.4 S, 252/301.4 F, 315/169.3, 315/169.4
• US Class Current: 313/487
• CPC Class Codes: F21S 41/00 Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps reversing lights F21S43/00
• CPC Class Codes: F21S 41/141 Light emitting diodes [LED]
• CPC Class Codes: F21S 41/176 Light sources where the light is generated by photoluminescent material spaced from a primary light generating element
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light-emitting device (2) including a light-emitting element (2a), a first phosphor (2b), and a second phosphor (2c). The light-emitting element (2a) emits light L1 having a wavelength range within the visible region. Upon receipt of the light L1, or light L3 originating from the second phosphor (2c), the first phosphor (2b) emits light L2 having a wavelength range, which differs from that of the first light L1 and the third light L3, but falls within the visible region. Upon receipt of a specific wavelength component (ultraviolet light, or the like) included in external light, the second phosphor (2c) generates the light L3 whose wavelength range is substantially the same as that of the light L1, thereby radiating the first phosphor (2b) with the light L3.

Claims

1. A light-emitting device configured to obtain a predetermined light source color by mixing a luminescent color and a fluorescent color, comprising:

a light-emitting element for emitting first light including a wavelength range that falls within a visible region;

a first phosphor for, upon receipt of said first light or a third light, emitting a second light including a wavelength range that differs from that of said first light and said third light but falls within a visible region; and

a second phosphor for, upon receipt of a specific wavelength component included in external light, generating said third light including a wavelength range that is substantially the same as that of said first light, thereby radiating said first phosphor with said third light.

2. The light-emitting device defined in claim 1, wherein

said first light and said third light have wavelength ranges including blue;

and

said second light has a wavelength range including yellow.

3. The light-emitting device defined in claim 1, wherein said second phosphor is excited by ultraviolet light.

4. The light-emitting device defined in claim 1, wherein

said first phosphor and said second phosphor are laminated, in this order, on said light-emitting element;

and

said first light and said second light are transmitted through said second phosphor.

5. The light-emitting device defined in claim 1, wherein phosphor nano-particles, having a particle size smaller than a wavelength of said first light, are employed as said second phosphor.

6. The light-emitting device defined in claim 2, wherein said second phosphor is excited by ultraviolet light.

7. The light-emitting device defined in claim 2, wherein

said first phosphor and said second phosphor are laminated, in this order, on said light-emitting element;

and

said first light and said second light are transmitted through said second phosphor.

8. The light-emitting device defined in claim 2, wherein phosphor nano-particles whose particle size is smaller than a wavelength of said first light are employed as said second phosphor.

9. The light-emitting device defined in claim 3, wherein

said first phosphor and said second phosphor are laminated, in this order, on said light-emitting element;

and

said first light and said second light are transmitted through said second phosphor.

10. The light-emitting device defined in claim 3, wherein phosphor nano-particles, having a particle size smaller than a wavelength of said first light, are employed as said second phosphor.

11. The light-emitting device defined in claim 6, wherein

said first phosphor and said second phosphor are laminated, in this order, on said light-emitting element;

and

said first light and said second light are transmitted through said second phosphor.

12. The light-emitting device defined in claim 6, wherein phosphor nano-particles, having a particle size smaller than a wavelength of said first light, are employed as said second phosphor.

13. A vehicle lamp, comprising:

a light-emitting device capable of obtaining a predetermined light source color by of mixing a luminescent color and a fluorescent color, and

an optical system for obtaining illumination light through use of said light-emitting device as a light source,

wherein said light-emitting device comprises;

a light-emitting element for emitting first light including a wavelength range that falls within a visible region;

a first phosphor for, upon receipt of said first light or a third light, emitting second light including a wavelength range that differs from that of said first light and third light but falls within a visible region; and

a second phosphor for, upon receipt of a specific wavelength component included in external light, generating said third light including a wavelength range that is substantially the same as that of said first light, thereby radiating said first phosphor with said third light.

14. The vehicle lamp defined in claim 13, wherein

said first light and said third light have wavelength ranges including blue;

and

said second light has a wavelength range including yellow.

15. The vehicle lamp defined in claim 13, wherein said second phosphor is excited by ultraviolet light.

16. The vehicle lamp defined in claim 13, wherein

said first phosphor and said second phosphor are laminated, in this order, on said light-emitting element;

and

said first light and said second light are transmitted through said second phosphor.

17. The vehicle lamp defined in claim 13, wherein phosphor nano-particles, having a particle size smaller than a wavelength of said first light, are employed as said second phosphor.