Light conversion structure and light-emitting device using the same

• US 8,044,572 B2
• Filed: 12/13/2005
• Issued: 10/25/2011
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: UBE Industries Limited
• Original Assignee: UBE Industries Limited
• Inventors: Sakata, Shin-ichi, Mitani, Atsuyuki, Fujii, Itsuhiro
• Primary Examiner(s): Patel; Nimeshkumar
• Assistant Examiner(s): Hollweg; Thomas A
• Application Number:
  US11/792,899
• Publication Number:
  US 20070257597A1
• Time in Patent Office: 2,142 Days
• Field of Search: 313484-487, 313498-503, 313/467, 313/468, 257 79-103
• US Class Current: 313/503
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/764 Garnet structure A3B2(CO4)3
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/9661 Colour
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/44 based on aluminates
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/653 Processes involving a melting step
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7792 Aluminates
• CPC Class Codes: H01L 2224/48091 Arched
• 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 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials

Abstract

A light conversion structure ensuring good light transmission and less deterioration and capable of controlling light to a desired color tone and emitting a highly bright light, and a light-emitting device using the same. The light conversion structure is a light conversion structure including a layer formed of a ceramic composite, which absorbs a part of a first light to emit a second light and transmits a part of the first light, and a fluorescent layer for the control of color tone, which is formed on the surface of the ceramic composite and which absorbs a part of the first light or a part of the second light to emit a third light and transmits a part of the first light or a part of the second light, wherein the ceramic composite includes a solidified body where at least two or more metal oxide phases are formed continuously and three-dimensionally entangled with each other, and at least one metal oxide phase in the solidified body includes a metal element oxide capable of emitting fluorescence.

Claims

1. A light emitting device comprising:

a light emitting element for emitting a first light,

a first layer of a ceramic composite which comprises a solidified body having formed therein an α

-Al₂O₃ phase and a Ce-activated Y₃Al₅O₁₂ (YAG;

Ce) or Tb-activated T₃Al₅O₁₂ (YAG;

Tb) phase continuously and three-dimensionally entangled with each other, in which said YAG;

Ce or YAG;

Tb phase emits a fluorescence and said α

-Al₂O₃ phase does not emit a fluorescence and transmits said first light, whereby said first layer absorbs a part of said first light to emit a second light and transmits a part of said first light, and

a second layer of a ceramic composite formed on the surface of said first layer for controlling color tone, wherein said ceramic composite of said second layer comprises a solidified body having formed therein a Cr-doped α

-Al₂O₃ phase and a Y₃Al₅O₁₂ (YAG) phase continuously and three-dimensionally entangled with each other, whereby said second layer absorbs a part of said first light and/or a part of said second light, emits a third light and transmits a part of said first light and/or a part of said second light,

wherein said light emitting device emits said first, second and third lights outward to obtain a desired white color tone light.

2. The light-emitting device as claimed in claim 1, wherein said light-emitting element is a light-emitting diode.