Light emitting device with blue light LED and phosphor components

• US 7,682,848 B2
• Filed: 02/08/2008
• Issued: 03/23/2010
• Est. Priority Date: 07/29/1996
• Status: Expired due to Fees

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Primary Examiner(s): Ghyka; Alexander G
• Assistant Examiner(s): MUSTAPHA, ABDULFATTAH B
• Application Number:
  US12/028,062
• Publication Number:
  US 20080138918A1
• Time in Patent Office: 774 Days
• Field of Search: 438/21, 438/27, 257/E33.044, 257/E33.059
• US Class Current: 438/21
• CPC Class Codes: C09K 11/7767 Chalcogenides
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: H01J 29/20 characterised by the luminescent material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45169 Platinum (Pt) as principal constituent
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/45 of an individual wire connector
• 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 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/12036 : PN diode
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/20751 : larger or equal to 10 microns less than 20 microns
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/20754 : larger or equal to 40 microns less than 50 microns
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements
• CPC Class Codes: H01L 33/501 : characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H05B 33/14 : characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A light emitting device containing a semiconductor light emitting component and a phosphor, the phosphor is capable of absorbing a part of light emitted by the light emitting component and emitting light of a wavelength different from that of the absorbed light, is provided. A straight line connecting a point of chromaticity corresponding to a spectrum generated by the light emitting component and a point of chromaticity corresponding to a spectrum generated by the phosphor is substantially along a black body radiation locus in a chromaticity diagram.

Claims

1. A method of making a light emitting device, said light emitting device comprising a semiconductor light emitting component and a phosphor capable of absorbing a part of light emitted by the light emitting component and emitting light of wavelength different from that of the absorbed light, said method comprising:

adjusting an amount of an In element of an active layer of the semiconductor light emitting component, and/or adjusting a composition rate of the phosphor in said light emitting device so that a straight line connecting a point of chromaticity corresponding to a spectrum generated by the light emitting component and a point of chromaticity corresponding to a spectrum generated by the phosphor is substantially along a black body radiation locus in a chromaticity diagram;

wherein said semiconductor light emitting component comprises a nitride compound semiconductor and is capable of emitting a blue color light which spectrum has a peak wavelength within the range from 420 to 490 nm, and

said phosphor is capable of absorbing a part of the blue color light thereby emitting light having a broad emission spectrum comprising a peak wavelength existing around the range from 510 to 600 nm and a tail continuing beyond 700 nm.

2. The method of making a light emitting device of claim 1, wherein said phosphor is made by the steps of:

dissolving rare earth elements in acid in stoichiometrical proportions,

coprecipitating the solution with oxalic acid to obtain a sediment,

firing the sediment to obtain an oxide, and firing a mixture of said oxide, an ammonium fluoride and aluminum oxide.