Semiconductor light emitting device including a fluorescent material

• US 6,661,030 B2
• Filed: 10/23/2001
• Issued: 12/09/2003
• Est. Priority Date: 09/01/1997
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Komoto, Satoshi, Konno, Kuniaki, Furukawa, Chisato, Sugawara, Hideto, Suzuki, Nobuhiro, Nitta, Koichi
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US10/002,467
• Publication Number:
  US 20020088985A1
• Time in Patent Office: 777 Days
• Field of Search: 257/89, 257/98, 257/99, 257/100, 313/512, 313/486
• US Class Current: 257/98
• CPC Class Codes: F21Y 2101/00 Point-like light sources
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 33/40 Materials therefor
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material

Abstract

A light emitting device or image display includes a fluorescent material as a wavelength converter for converting a wavelength into another. The fluorescent material is disposed in a predetermined positional relation, to prevent external leakage of primary light and to extract secondary light made by wavelength-converting the primary light with a very high efficiency. By using a semiconductor light emitting element for ultraviolet emission and combining it with a fluorescent material or any other appropriate material having a wavelength converting function, various kinds of applications, such as illuminator, having a remarkably long-life light source can be made. The semiconductor light emitting element preferably has a emission wavelength near 330 nm, and preferably uses BGaN in its light emitting layer.

Claims

1. A semiconductor light emitting device comprising:

a packaging member;

a semiconductor light emitting element mounted on the packaging member,

the semiconductor light emitting element including a first semiconductor layer of a first conduction type, a light emitting layer located on the first semiconductor layer for emitting primary light having a first wavelength, and a second semiconductor layer of a second conduction type, the light emitting layer containing a material selected from the group consisting of gallium nitride, zinc selenide, silicon carbide and boron nitride; and

a layer of fluorescent material absorbing the primary light emitted from the light emitting layer and to emit secondary light having a second wavelength different from the first wavelength, the layer of fluorescent material including an adhesive material which binds the fluorescent material,

wherein the layer of fluorescent material includes a material selected from the group consisting of inorganic polymer, rubber material, farinaceous material and protein, which binds the fluorescent material.

2. The semiconductor light emitting device according to claim 1, wherein the fluorescent material is dispersed on a solvent.

3. The semiconductor light emitting device according to claim 1, further comprising a resin molded so that the light emitting element and the layer of fluorescent material are covered.

4. The semiconductor light emitting device according to claim 3, wherein a refractive index of fluorescent material is between a refractive index of the surface of the light emitting element and a refractive index of the resin.

5. The semiconductor light emitting device according to claim 1, wherein the layer of fluorescent material is coated on a top surface and on a side surface of the light emitting element.

6. The semiconductor light emitting device according to claim 1, wherein the packaging member is a selected one from the group consisting of lead frame, stem and substrate.

7. The semiconductor light emitting device according to claim 1, wherein the light emitting layer contains a gallium nitride compound semiconductor and the second wavelength is longer than the first wavelength.

8. The semiconductor light emitting device according to claim 1, wherein the light emitting layer contains a gallium nitride compound semiconductor including indium.

9. The semiconductor light emitting device according to claim 1, wherein the light emitting layer contains a material selected from the group consisting of zinc selenide, silicon carbide, and boron nitride, and the second wavelength is longer than the first wavelength.

10. The semiconductor light emitting device according to claim 1, wherein the first wavelength is not longer than 380 nm.

11. A semiconductor light emitting device comprising:

a packaging member;

a semiconductor light emitting element mounted on the packaging member to emit primary light having a first wavelength; and

a layer containing a fluorescent material to absorb the primary light emitted from the light emitting element and to emit secondary light having a second wavelength different from the first wavelength,

wherein the layer is provided between the packaging member and the light emitting element and the layer includes an adhesive material which fixes the light emitting element to the packaging member.

12. The semiconductor light emitting device according to claim 11, wherein the packaging member is selected one from the group consisting of lead frame, stem and substrate.

13. The semiconductor light emitting device according to claim 11, wherein the layer includes a material selected from the group consisting of resin materials, rubber materials, organic materials, inorganic materials, farinaceous materials, protein materials, tar materials and metal solders.

14. The semiconductor light emitting device according to claim 11, wherein a part of the primary light is output to outside directly without passing through the fluorescent material.

15. The semiconductor light emitting device according to claim 11, wherein the light emitting element has a light emitting layer containing a gallium nitride compound semiconductor and the second wavelength is longer than the first wavelength.

16. The semiconductor light emitting device according to claim 11, wherein the light emitting layer contains a gallium nitride compound semiconductor including indium.

17. The semiconductor light emitting device according to claim 11, wherein the light emitting element has a light emitting layer made of a material selected from the group consisting of ZnSe, ZnSSe, ZnS, BN and SiC, and the second wavelength is longer than the first wavelength.

18. The semiconductor light emitting device according to claim 11, wherein the first wavelength is not longer than 380 nm.

19. The semiconductor light emitting device according to claim 11, wherein the second wavelength is in a range of a visible region.

20. The semiconductor light emitting device according to claim 11, wherein the secondary light has at least three wavelength peaks each of which substantially corresponds to red, green and blue, respectively.

21. A semiconductor light emitting device comprising:

a packaging member;

a semiconductor light emitting element mounted on the packaging member to emit primary light having a first wavelength;

a wire connecting the packaging member and the semiconductor light emitting element, the wire being connected on a first side of the light emitting element; and

a layer containing a fluorescent material to absorb the primary light emitted from the light emitting element and to emit secondary light having a second wavelength different from the first wavelength, the layer being provided on a second side of the light emitting element, the second side being opposite to the first side

wherein a part of the primary light is output to outside directly without passing through the fluorescent material.

22. The semiconductor light emitting device according to claim 21, wherein the packaging member is selected one from the group consisting of lead frame, stem and substrate.

23. The semiconductor light emitting device according to claim 21, wherein the layer includes an adhesive which fixes the light emitting element to the packaging member.

24. The semiconductor light emitting device according to claim 21, wherein the layer includes a material selected from the group consisting of resin materials, rubber materials, organic materials, inorganic materials, farinaceous materials, protein materials, tar materials and metal solders.

25. The semiconductor light emitting device according to claim 21, wherein the light emitting element has a light emitting layer containing a gallium nitride compound semiconductor and the second wavelength is longer than the first wavelength.

26. The semiconductor light emitting device according to claim 21, wherein the light emitting layer contains a gallium nitride compound semiconductor including indium.

27. The semiconductor light emitting device according to claim 21, wherein the light emitting element has a light emitting layer made of a material selected from the group consisting of ZnSe, ZnSSe, ZnS, BN and SiC, and the second wavelength is longer than the first wavelength.

28. The semiconductor light emitting device according to claim 21, wherein the first wavelength is not longer than 380 nm.

29. The semiconductor light emitting device according to claim 21, wherein the second wavelength is in a range of a visible region.

30. The semiconductor light emitting device according to claim 21, wherein the secondary light has at least three wavelength peaks each of which substantially corresponds to red, green and blue, respectively.