Light emitting device

• US 7,319,289 B2
• Filed: 03/10/2004
• Issued: 01/15/2008
• Est. Priority Date: 03/10/2003
• Status: Expired due to Fees

• Current Assignee: Sumita Optical Glass, Inc., Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Sumita Optical Glass, Inc., Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Kato, Hideaki, Suehiro, Yoshinobu, Inoue, Mitsuhiro, Terajima, Tohru, Aida, Kazuya, Sawanobori, Naruhito
• Primary Examiner(s): Patel; Ashok
• Application Number:
  US10/796,302
• Publication Number:
  US 20040207998A1
• Time in Patent Office: 1,406 Days
• Field of Search: 313/498, 313/501, 313/502, 313/503, 313/506, 313/512, 313484-487, 313/493, 313/636, 313/474, 313/112, 313/478, 362/260, 362/296, 362/310, 362/341, 362/307
• US Class Current: 313/485
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin

Abstract

A light emitting device has a light emitting element, and a phosphor layer of phosphor glass to generate fluorescence while being excited by light emitted from the light emitting element. The light emitting element emits ultraviolet light, and the phosphor glass generates visible fluorescence while being excited by the ultraviolet light.

Claims

1. A light emitting device, comprising:

a light emitting element to emit ultraviolet light;

a phosphor layer that includes phosphor glass to generate fluorescence while being excited by the ultraviolet light emitted from the light emitting element; and

an optical system to converge the ultraviolet light emitted from the light emitting element,

wherein the light emitting element is disposed opposite the optical system, and the optical system is disposed in an optical axis direction of the light emitting element.

2. The light emitting device according to claim 1, wherein:

the phosphor glass includes, as a glass component, at least one of Tb³⁺ (terbium), Eu²⁺ (divalent europium) and Eu³⁺ (trivalent europium).

3. The light emitting device according to claim 1, wherein:

the optical system comprises a convex lens.

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

the phosphor layer includes a transparent material and particles including said phosphor glass that are dispersed in the transparent material.

5. The light emitting device according to claim 4, wherein:

the particles including said phosphor glass include different kinds of phosphor glass.

6. The light emitting device according to claim 4, wherein:

the phosphor layer includes a phosphor material other than the phosphor glass, the phosphor material being dispersed in the transparent material.

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

the optical system comprises a reflection mirror.

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

the phosphor glass comprises a low-melting phosphor glass doped with a fluorescence activation element.

9. The light emitting device according to claim 1, wherein:

the phosphor glass comprises a fluorophosphate glass.

10. The light emitting device according to claim 1, wherein:

the phosphor layer includes a plurality of layers including different kinds of phosphor glass.

11. The light emitting device according to claim 1, wherein:

the optical system is disposed away from the light emitting element.

12. The light emitting device according to claim 1, wherein:

the optical system comprises a reflection mirror that is disposed anteriorly in the optical axis direction of the light emitting element and away from the light emitting element, and

the phosphor layer is disposed posteriorly in the optical axis direction of the light emitting element.

13. The light emitting device according to claim 1, wherein:

the phosphor layer is disposed at a window of a housing in which the light emitting element is housed.

14. The light emitting device according to claim 1, wherein:

the phosphor layer is disposed at a window of a housing in which the light emitting element is housed, and

the phosphor layer is formed planar.

15. A light emitting device, comprising:

a light emitting element; and

a phosphor layer that includes phosphor glass to generate fluorescence while being excited by light emitted from the light emitting element,

wherein the light emitting element emits ultraviolet light, and the phosphor glass generates visible fluorescence while being excited by the ultraviolet light, and the phosphor glass comprises a low-melting phosphor glass doped with a fluorescence activation element,

wherein;

the phosphor layer includes a plurality of layers including different kinds of phosphor glass.