Preparation of White Light Emitting Diode Using a Phosphor

• US 20080185602A1
• Filed: 04/25/2006
• Published: 08/07/2008
• Est. Priority Date: 05/02/2005
• Status: Abandoned Application

• Current Assignee: Korea Research Institute of Chemical Technology
• Original Assignee: Korea Research Institute of Chemical Technology
• Inventors: Kim, Kyung Nam, Park, Joung Kyu, Kim, Chang Hae, Choi, Kyoung Jae, Kim, Jae Myung
• Application Number:
  US11/912,614
• Publication Number:
  US 20080185602A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/7786 with alkaline earth metals
• CPC Class Codes: H01L 2224/45144 Gold (Au) 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 2224/49107 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 33/504 Elements with two or more wavelength conversion materials
• 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

The present invention relates to a method for preparing a white light emitting diode (LED) using phosphors, especially to a white light emitting diode prepared by applying a tri-color phosphor material mixture of red, blue and green on a UV LED chip made of a packaging substrate, where white light is obtained by transmitting light through the tri-color phosphor mixture since the UV LED chip emits purple light. In particular, the present invention relates to a white light emitting diode prepared by laminating green and red or yellow and red phosphor materials on a blue LED chip, where white light is obtained as light is transmitted and absorbed by the phosphors. The method in accordance with the present invention is advantageous in that a white light emitting diode having superior photoluminescence efficiency can be provided using a single chip.

Claims

1. (canceled)

2. A method for preparing a white light emitting diode comprising a blue LED chip attached to the mount of a packaging substrate or a lead frame by Ag paste, a Au wire that connects the electrodes of the lead frame and the blue LED chip and a transparent resin that encloses and protects the LED chip and the Au wire, in which a two-color phosphor material mixture of red and green or yellow and red is applied to the blue LED chip directly or indirectly, so that white light is obtained as the blue light emitted from the blue LED chip passes through the two-color phosphor material mixture, where the blue LED chip emits light in the wavelength range of 450 to 480 nm.

4. The method for preparing a white light emitting diode as set forth in claim 2, wherein the red phosphor material is at least one selected from the group consisting of a silicate-based Sr3SiO5:

Eu phosphor;

a sulfide-based phosphor in which Eu is used as active agent and the matrix has the formula (Srx, Cay)S, where 0≦

x≦

1 and 0≦

y≦

1, typically SrS;

Eu or CaS;

Eu; and

a SrY2S4;

Eu phosphor.

5. The method for preparing a white light emitting diode as set forth in claim 2, wherein the green phosphor material is at least one selected from the group consisting of a silicate-based phosphor of the formula (Srx, Bay, Caz)2SiO4:

Eu, where 0≦

x≦

1, 0≦

y≦

1 and 0≦

z≦

1, typically Sr2SiO4;

Eu, Ba2SiO4;

Eu or Ca2SiO4;

Eu;

a thiogallate-based phosphor in which Eu is used as active agent and the matrix has the formula (Srx, Bay, Caz)Ga2S4, where 0≦

x≦

1, 0≦

y≦

1 and 0≦

z≦

1, typically SrGa2S4;

Eu, BaGa2;

Eu, CaGa2S4;

Eu or Sr2Ga2S5;

Eu; and

a thioaluminate-based phosphor of the formula (Srx, Bay, Caz)Al2S4, where 0≦

x≦

1, 0≦

y≦

1 and 0≦

z≦

1, typically SrAl2S4;

Eu, BaAl2S4;

Eu or Sr2Al2S5;

Eu.

8. The method for preparing a white light emitting diode as set forth in claim 2, wherein the red phosphor material and the green phosphor material are mixed at a proportion of 1-2:

1-2.

9. A lighting device comprising a white light emitting diode prepared by the method as set forth in claim 2.

10. A display device comprising a white light emitting diode prepared by the method as set forth in claim 2.

11. A backlight device comprising a white light emitting diode prepared by the method as set forth in claim 2.

3. (canceled)

6. (canceled)

7. (canceled)