Light-emitting unit

• US 6,717,355 B2
• Filed: 08/27/2001
• Issued: 04/06/2004
• Est. Priority Date: 08/28/2000
• Status: Expired

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Takahashi, Yuji, Ota, Koichi, Kaga, Koichi, Ota, Akihito
• Primary Examiner(s): Patel, Ashok
• Assistant Examiner(s): ZIMMERMAN, GLENN D
• Application Number:
  US09/938,624
• Publication Number:
  US 20020043926A1
• Time in Patent Office: 953 Days
• Field of Search: 313/502, 313/503, 257/98, 252/301.4 R, 252/301.4 F
• US Class Current: 313/503
• CPC Class Codes: C03C 3/045 Silicon oxycarbide, oxynitride or oxycarbonitride glasses
• CPC Class Codes: C03C 4/12 for luminescent glass; for fluorescent glass
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• 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 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

A light-emitting device with an emission wavelength range of from 360 nm to 550 nm and a fluorescent material made of Ca—Al—Si—O—N oxynitride activated with Eu²⁺ are used so that a part of light emitted from the light-emitting device is emitted while the wavelength of the part of light is converted by the fluorescent material.

Claims

1. A light-emitting unit comprising:

a light-emitting device for emitting light with a wavelength range of from 360 nm to 550 nm; and

a fluorescent material comprising Ca—

Al—

Si—

O—

N oxynitride activated with Eu²⁺,

wherein at least a part of said light emitted from said light-emitting device is subjected to wavelength conversion by said fluorescent material.

2. A light-emitting unit according to claim 1, wherein said light-emitting device emits light with a wavelength range of from 450 nm to 550 nm, and wherein said part of said light with the converted wavelength is mixed with the other part of said light emitted from said light-emitting device, so that white light is emitted.

3. A light-emitting unit according to claim 1, further comprising:

a light transmissible material,

wherein said fluorescent material comprises one of a powdery material and a granular material and is formed in said light-transmissible material.

4. A light-emitting unit according to claim 1, wherein said fluorescent material comprises a glassy material.

5. A light-emitting unit according to claim 1, wherein said light-emitting device comprises a group III nitride compound semiconductor light-emitting device.

6. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted in a cup portion provided in a lead frame, and the cup portion is filled with the light-transmissible material including the fluorescent material.

7. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted in a cup portion provided in a lead frame, and a fluorescent layer made from the light-transmissible material including the fluorescent material is provided on a surface of the light-emitting device.

8. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted in a cup portion provided in a lead frame, and the light-emitting device and a part of the lead frame are covered with the light-transmissible material including the fluorescent material.

9. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted on a substrate, and a fluorescent layer comprising the light-transmissible material including the fluorescent material is provided on a surface of the light-emitting device.

10. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted on a substrate, and the light-emitting device is sealed with the light-transmissible material including the fluorescent material.

11. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted in a cup portion provided in a substrate, and the cup portion is filled with the light-transmissible material including the fluorescent material.

12. A light-emitting unit according to claim 3, wherein the light-emitting device is mounted in a cup portion provided in a substrate, and a fluorescent layer made from the light-transmissible material including the fluorescent material is provided on a surface of the light-emitting device.

13. A light-emitting unit according to claim 3, wherein a fluorescent layer made from the light-transmissible material including the fluorescent material is provided on a substrate surface of the light-emitting device.

14. A light-emitting unit according to claim 13, wherein a fluorescent layer made form the light-transmissible material including the fluorescent material is also provided on a side surface of the light-emitting device.

15. A light-emitting unit according to claim 3, wherein a reflection plate is provided in a light-emitting direction of the light-emitting device.

16. A light-emitting unit according to claim 15, wherein a fluorescent layer made from the light-transmissible material including the fluorescent material is provided on a surface of the reflection plate opposite to the light-emitting device.

17. A light-emitting unit according to claim 3, wherein a fluorescent layer made from the light-transmissible material including the fluorescent material is provided in a light-emitting direction of the light-emitting device.

18. A light-emitting unit according to claim 17, further comprising:

a light guide having a light introduction surface and a light-emitting surface,

wherein the light-emitting device is disposed so as to face the light introduction surface of the light guide, and the fluorescent layer is disposed between the light-emitting device and the light introduction surface of the light guide.

19. A light-emitting unit according to claim 17, further comprising:

a light guide having a light introduction surface and a light-emitting surface,

wherein the light-emitting device is disposed so as to face the light introduction surface of the light guide, and the fluorescent layer is disposed on the light-emitting surface side of the light guide.

20. A light-emitting unit according to claim 19, further comprising:

a layer of a light-transmissible material disposed between the light guide and the fluorescent layer.

21. A light-emitting unit according to claim 4, wherein a fluorescent layer comprising the fluorescent material is provided on a substrate surface of the light-emitting device.

22. A light-emitting unit according to claim 21, wherein a fluorescent layer comprising the fluorescent material is also provided on a side surface of the light-emitting device.

23. A light-emitting unit according to claim 4, wherein a reflection plate is provided in a light-emitting direction of the light-emitting device.

24. A light-emitting unit according to claim 23, wherein the reflection plate comprises the fluorescent material, and a surface of the reflection plate opposite to a surface facing the light-emitting device is planished as a mirror surface.

25. A light-emitting unit according to claim 4, wherein a fluorescent layer comprising the fluorescent material is provided in a light-emitting direction of the light-emitting device.

26. A light-emitting unit according to claim 25, further comprising:

a light guide having a light introduction surface and a light-emitting surface,

wherein the light-emitting device is disposed so as to face the light introduction surface of the light guide, and the fluorescent layer is disposed between the light-emitting device and the light introduction surface of the light guide.

27. A light-emitting unit according to claim 25, further comprising:

a light guide having a light introduction surface and a light-emitting surface,

wherein the light-emitting device is disposed so as to face the light introduction surface of the light guide, and the fluorescent layer is disposed on the light-emitting surface side of the light guide.

28. A light-emitting unit according to claim 27, further comprising:

a layer of a light-transmissible material disposed between the light guide and the fluorescent layer.

33. A light-emitting unit according to claim 1, wherein said fluorescent material has a mean grain size which is not greater than 20 μ

m.

34. A light-emitting unit according to claim 1, wherein said fluorescent material has a mean grain size which is not greater than 10 μ

m.

35. A light-emitting unit according to claim 1, wherein said fluorescent material has a mean grain size which is not greater than 5 μ

m.

36. A light-emitting unit according to claim 3, wherein said light transmissible material comprises one of epoxy resin, silicone resin, urea resin and glass.

29. A light-emitting method comprising:

irradiating a fluorescent material made of Ca—

Al—

Si—

O—

N oxynitride activated with Eu²⁺ with light emitted from a light-emitting device with an emission wavelength range of from 360 nm to 550 nm to thereby convert the wavelength of a part of said light; and

mixing said part of said light with the converted wavelength with the other part of said light emitted from said light-emitting device to thereby emit resultant light,

wherein said light-emitting device is turned on intermittently.

30. A light-emitting method according to claim 29, wherein the time when said light-emitting device is turned on is adjusted to thereby adjust the color of light emitted from said light-emitting unit.

31. A light-emitting method according to claim 30, wherein said light-emitting device emits light with an emission wavelength range of from 480 nm to 550 nm, and wherein said color of said emitted light is white.

32. A light-emitting method according to claim 29, wherein said light-emitting device comprises a group III nitride compound semiconductor light-emitting device.

37. A fluorescent material for a light-emitting unit, said material comprising Ca—

Al—

Si—

O—

N oxynitride activated with Eu²⁺.