Light emitting film, luminescent device, method for manufacturing light emitting film and method for manufacturing luminescent device

• US 20060170332A1
• Filed: 03/12/2004
• Published: 08/03/2006
• Est. Priority Date: 03/13/2003
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Tamaki, Hiroto, Sofue, Shinsuke, Izuno, Kunihiro, Takeichi, Junji
• Granted Patent: US 7,923,918 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/0811 with zinc or cadmium
• CPC Class Codes: C09K 11/0844 Germanates
• CPC Class Codes: C09K 11/0855 Phosphates
• CPC Class Codes: C09K 11/7728 containing europium
• 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 2224/49107 on the semiconductor or solid-state body
• 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

Abstract

The present invention provides a reliable, long-life phosphor, or the like, which is prevented from darkening due to aging. A light emitting apparatus has a light emitting element and a phosphor layer. The phosphor layer has a phosphor excited by light from the light emitting element, and a binder which binds the phosphor. The binder is hydroxide oxide gel obtained by curing sol of a hydroxide oxide mixed with sol containing at least one metallic element selected from the group consisting of Al, Y, Gd, Lu, Sc, Ga, In, and B. Transmittance of hydroxide oxide in a gel state is higher than the transmittance in the polycrystal state where the sol-gel reaction is proceeded. In addition, the content of hydroxyl group or water of crystallization in the hydroxide oxide is 10% or less by weight.

Claims

1. A luminescent film for coating a light emitting element comprising:

a filler member including at least a luminescent material; and

a binder member, wherein said binder member contains at least a hydroxide oxide of metallic element.

2. The luminescent film according to claim 1, wherein said luminescent material is an inorganic phosphor, said filler member is an inorganic filler, and said binder member is an inorganic binder consisting principally of the hydroxide oxide of metallic element with a constant ionic charge number.

3. The luminescent film according to claim 1, wherein said luminescent material is an inorganic phosphor, said filler member is an inorganic filler, and said binder member is an inorganic binder consisting principally of the hydroxide oxide of metallic element, wherein said hydroxide oxide of metallic element is at least a hydroxide oxide of IIIA or IIIB group element.

4. The luminescent film according to claim 3, wherein said IIIA or IIIB group element contains at least one element selected from the group consisting of Sc, Y, Gd and Lu, or the group consisting of B, Al, Ga and In.

5. The luminescent film according to claim 1, wherein the hydroxide oxide of metallic element contained in said binder member is at least a hydroxide oxide of Al having boehmite structure or pseudoboehmite structure.

6. The luminescent film according to claim 1, wherein said binder member contains the hydroxide oxide of aluminum, and 0.5% to 50% of hydroxide oxide of IIIA or IIIB group element other than said aluminum by weight relative to the binder member.

7. The luminescent film according to claim 1, wherein said binder member contains 0.5% to 50% of boron oxide or boric acid by weight relative to the binder member.

8. The luminescent film according to claim 1, wherein the hydroxide oxide of metallic element contained in said binder member is a hydroxide oxide of yttrium.

9. The luminescent film according to claim 8, wherein said binder member contains the hydroxide oxide of yttrium, and 0.5% to 50% of hydroxide oxide of IIIA or IIIB group element other than said yttrium by weight relative to the binder member.

11. The luminescent film according to claim 1, wherein said binder member is a porous material with bridge structure, network structure or polymer structure which is formed of particle aggregation containing said hydroxide oxide.

12. The luminescent film according to claim 1, wherein said binder member is in a gel state which is filled with inorganic particles containing said hydroxide oxide.

13. The luminescent film according to claim 12, wherein the light transmittance of said luminescent film is higher than the transmittance in a polycrystalline substance or amorphous substance in the case of sintering after sol-gel reaction.

14. The luminescent film according to claim 1, wherein said binder member contains 10% or less of hydroxyl group or water of crystallization by weight relative to the binder member.

15. The luminescent film according to claim 1, wherein the weight ratio between the filler member and the binder member which compose said luminescent film is 0.05 to 30 of filler/binder.

10. (canceled)

16. A light emitting apparatus comprising a light emitting element, and a luminescent layer, which absorbs a part of light from said light emitting element and emits luminescent radiation, wherein said luminescent layer is a luminescent film which coats said light emitting element includes a filler member containing at least a luminescent material and a binder member containing at least a hydroxide oxide of metallic element.

17. The light emitting apparatus according to claim 16, wherein said luminescent layer directly coats said light emitting element.

18. The light emitting apparatus according to claim 16, wherein said luminescent layer includes phosphor particles excited by the light of said light emitting element, and a binder member which binds said phosphor particles dispersed in the layer.

19. The light emitting apparatus according to claim 16, wherein said light emitting apparatus comprises a semiconductor light emitting element with light-emission wavelength of 550 nm or less, and a phosphor which is excited by light of said wavelength and emits luminescent radiation.

20. The light emitting apparatus according to claim 16, wherein said light emitting apparatus comprises a semiconductor light emitting element with light-emission wavelength of 410 nm or less, and a phosphor which is excited by light of said wavelength and emits luminescent radiation.

21. The light emitting apparatus according to claim 16, wherein the luminescent layer of said light emitting apparatus emits luminescent radiation at temperature of 50°

C. or more of the luminescent layer.

22. The light emitting apparatus according to claim 16, wherein the luminescent layer of said light emitting apparatus is formed so as to be in intimate contact with said semiconductor light emitting element, and the injection electric power during drive of said semiconductor light emitting element is 0.1 W/cm² or more.

23. The light emitting apparatus according to claim 16, wherein the light-emission wavelength of said semiconductor light emitting element of said light emitting apparatus is 410 nm or less, and the luminance maintenance ratio of said luminescent layer is 80% or more after said semiconductor light emitting element is driven at injection electric power of 1 W/cm² or more for 1000-hour operation.

24. The light emitting apparatus according to claim 16, wherein the phosphor contained in the filler of the luminescent layer of said light emitting apparatus includes at least one phosphor selected from the group consisting of blue luminescent phosphor, bluish green luminescent phosphor, green luminescent phosphor, yellowish green luminescent phosphor, yellow luminescent phosphor, yellowish red luminescent phosphor, orange luminescent phosphor, and red luminescent phosphor, and emits white group or neutral-color group luminescent radiation.

25. The light emitting apparatus according to claim 16, wherein the phosphor contained in the filler of the luminescent layer of said light emitting apparatus is a rare-earth aluminate phosphor activated by at least Ce, and emits green to yellowish red luminescent radiation of peak wavelength 510 nm to 600 nm.

26. The light emitting apparatus according to claim 16, wherein the phosphor contained in the filler of the luminescent layer of said light emitting apparatus is an alkaline-earth silicon-nitride phosphor activated by at least Eu, and emits yellowish red to red luminescent radiation of peak wavelength 580 nm to 650 nm.

27. The light emitting apparatus according to claim 16, wherein the phosphor contained in the filler of the luminescent layer of said light emitting apparatus is an alkaline-earth silicon nitride oxide phosphor activated by at least Eu, and emits bluish green to yellowish red luminescent radiation of peak wavelength 500 nm to 600 nm.

28. The light emitting apparatus according to claim 16, wherein the light emitting element of said light emitting apparatus is a semiconductor light emitting element which emits light with light-emission wavelength of 410 nm or less, and the phosphor contained in the filler of said luminescent layer contains at least one phosphor selected from the group consisting of alkaline-earth halogen apatite phosphor activated by at least Eu, alkaline-earth halogen boric-acid phosphor activated by at least Eu and alkaline-earth aluminate phosphor activated by at least Eu, which emit blue luminescent radiation, and is mixed with a rare-earth aluminate phosphor activated by at least Ce, which emit green to yellowish red luminescent radiation to emit white group luminescent radiation.

29. The light emitting apparatus according to claim 16, wherein the light emitting element of said light emitting apparatus is a semiconductor light emitting element which emits light with light-emission wavelength of 410 nm or less, and the phosphor contained in the filler of said luminescent layer contains at least one phosphor selected from the group consisting of alkaline-earth halogen apatite phosphor activated by at least Eu, alkaline-earth halogen boric-acid phosphor activated by at least Eu and alkaline-earth aluminate phosphor activated by at least Eu, which emit blue luminescent radiation, and is mixed with a rare-earth aluminate phosphor activated by at least Ce, which emit green to yellowish red luminescent radiation, and an alkaline-earth silicon-nitride phosphor activated by at least Eu, which emit yellowish red to red luminescent radiation to emit white group luminescent radiation.

30. The light emitting apparatus according to claim 16, wherein the light emitting element of said light emitting apparatus is a semiconductor light emitting element which emits light with light-emission wavelength of 440 nm to 480 nm in the blue region, and the phosphor contained in the filler of said luminescent layer is mixed with a rare-earth aluminate phosphor activated by at least Ce to emit white group luminescent radiation.

31. The light emitting apparatus according to claim 16, wherein the light emitting element of said light emitting apparatus is a semiconductor light emitting element which emits light with light-emission wavelength of 440 nm to 480 nm in the blue region, and the phosphor contained in the filler of said luminescent layer is mixed with a rare-earth aluminate phosphor activated by at least Ce, which emit green to yellowish red luminescent radiation, and an alkaline-earth silicon-nitride phosphor activated by at least Eu, which emit yellowish red to red luminescent radiation, to emit white group luminescent radiation.

32. A method for producing a luminescent film, which coats a light emitting element and includes at least a filler member containing a luminescent material and a binder member, comprising steps of:

preparing slurry by mixing metalloxane sol which contains a metallic element as a binder member and a filler member;

forming said slurry in a film shape;

binding the filler member with the binder member composed of structure of aggregation particles, in which the particles containing the hydroxide oxide of said metallic element aggregate by thermally curing said slurry formed in a film shape.

33. The method for producing a luminescent film according to claim 32, wherein said metalloxane sol is at least aluminoxane or yttrium-oxane sol.

34. A method for producing a light emitting apparatus including a light emitting element and a luminescent film, which coats at least a part light emitting element and includes a filler member containing at least a luminescent material and a binder member, comprising steps of:

preparing slurry by mixing metalloxane sol which contains a metallic element as a binder member with a filler member;

forming said slurry, which coats said light emitting element and/or an area spaced from the light emitting element under thermal treatment, in a film shape; and

binding the filler member with of the binder member composed of structure of aggregation particles, in which the particles containing the hydroxide oxide of said metallic element aggregate by thermally curing the slurry formed in a film shape.

35. A light emitting apparatus comprising a light emitting element, and a base member on which said light emitting element is mounted, wherein said light emitting element is coated with an inorganic binder, said inorganic binder is coated with resin, said inorganic binder is impregnated with said resin, and said inorganic binder is formed in an inorganic binder layer which coats at least parts of said light emitting element and said base member.

36. The light emitting apparatus according to claim 35, wherein as for said inorganic binder, voids contained in said inorganic binder layer are filled with said resin.

37. The light emitting apparatus according to claim 35, wherein as for said inorganic binder, substantially 95% or more of voids contained in said inorganic binder layer are filled with said resin.

38. The light emitting apparatus according to claim 35, wherein in coating said inorganic binder with said resin, said inorganic binder is impregnated with said resin by potting means or spray means.

39. The light emitting apparatus according to claim 35, wherein said inorganic binder contains a phosphor.

40. The light emitting apparatus according to claim 35, wherein said resin is formed in a resin layer which coats at least a part of said inorganic binder.

41. The light emitting apparatus according to claim 40, wherein the surface of said resin layer is smooth.

42. The light emitting apparatus according to claim 35, wherein said resin contains at least any of oil, gel, and rubber.

43. The light emitting apparatus according to claim 35, wherein said resin is silicone resin having a dialkylsiloxane skeleton before or after molding.

44. The light emitting apparatus according to claim 35, wherein said resin has dimethylsiloxane as a principal chain before molding.

45. The light emitting apparatus according to claim 35, wherein in bonding absorbance intensity of infrared spectral spectrum, strength ratio of C—

Si—

O bonding relative to Si—

O—

Si bonding in the composition of said resin is 1.2/1 or more.

46. A method for producing a light emitting apparatus comprising:

a first step of mounting a light emitting element onto a base member;

a second step of coating the light emitting element with an inorganic binder; and

a third step of coating the inorganic binder with resin, wherein said inorganic binder is coated with said resin by potting means or spray means in said third step.

47. The method for producing a light emitting apparatus according to claim 46, wherein impregnation is performed in a vacuum in said third step.

48. A light emitting apparatus comprising a light emitting element, and a luminescent layer which absorbs a part of light from said light emitting element and emits luminescent radiation of different wavelength, wherein said luminescent layer includes phosphor particles excited by the light of said light emitting element, and a binder member which binds said phosphor particles dispersed in the layer and contains at least one element selected from the group consisting of Sc, Y, Gd, Lu, B, Al, Ga, and In.