Tb, b-based yellow phosphor, its preparation method, and white semiconductor light emitting device incorporating the same

• US 20050269592A1
• Filed: 11/15/2003
• Published: 12/08/2005
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: Luxpia Co., Ltd.
• Original Assignee: Luxpia Co., Ltd.
• Inventors: Kim, Yong-Tae, Kim, Jin-Hwan, Lee, Dong-Yeoul, Kim, Eun-Joung
• Granted Patent: US 7,176,501 B2
• Time in Patent Office: Days
• US Class Current: 257/100
• CPC Class Codes: C09K 11/778 Borates
• 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 2224/8592 Applying permanent coating, e.g. protective coating
• 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: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The present invention relates to a terbium borate-based yellow phosphor, a preparation method thereof, and a white semiconductor light emitting device incorporating the same. The terbium borate-based yellow phosphor of the present invention is represented by the general formula (Tb_1-x-y-zRE_XA_y)₃D_aB_bO₁₂:Ce_z (where, RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb; A is a typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr; D is a typical amphoteric element selected from the group consisting of Al, In and Ga; 0≦x<0.5; 0≦y<0.5; 0<z<0.5; 0<a<5; and 0<b<5). The white semiconductor light emitting device of the present invention comprises a semiconductor light emitting diode and the yellow phosphor, which absorbs a portion of light emitted by the semiconductor light emitting diode and emits light of wavelength different from that of the absorbed light. It offers white light from the combination of the light emitted by the semiconductor light emitting diode and the light emitted by the yellow phosphor. The white semiconductor light emitting device of the present invention offers a greatly improved color rendering and experiences less deterioration in light emission efficiency over a long period of service.

Claims

1. A terbium borate-based yellow phosphor represented by the following general formula:

(Tb_1-x-y-zRe_xA_y)₃D_aB_bO₁₂;

Ce_z

wherein;

RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb;

A is at least one typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr;

D is at least one typical amphoteric element selected from the group consisting of Al, In and Ga;

0≦

x<

0.5;

0≦

y<

0.5;

0<

z<

0.5;

0<

a<

5; and

0<

b<

5.

2. The terbium borate -based yellow phosphor according to claim 1, wherein x, y, z, a and b are selected to satisfy:

0<

x+y+z<

1; and

4≦

a+b≦

7.

3. The terbium borate -based yellow phosphor according to claim 1, wherein the phosphor has an absorption peak in the range from about 420 nm to 480 nm and an emission peak in the range from about 530 nm to 570 nm.

4. A preparation method of a terbium borate-based yellow phosphor comprising:

preparing a precursor solution containing a compound containing at least one element selected from the group consisting of aluminum, indium and gallium, a terbium-containing compound, a cerium-containing compound and boric acid;

forming droplets by spraying said precursor solution; and

drying and pyrolyzing said droplets at 200 to 1,500°

C. and heat treating the same at 800 to 1,800°

C.

5. A white semiconductor light emitting device comprising:

a semiconductor light emitting diode; and

a phosphor coating layer comprising a yellow phosphor that absorbs a portion of light emitted by said semiconductor light emitting diode and emits light of wavelength different from that of the absorbed light and a transparent resin;

wherein said yellow phosphor comprises cerium-activated terbium, boron and amphoteric typical element, and said amphoteric typical element is selected from a group consisting of Al, In and Ga, and the mixture of the foregoing.

6. The white semiconductor light emitting device according to claim 5, wherein said phosphor is represented by the following general formula:

(Tb_1-x-y-zRe_xA_y)₃D_aB_bO₁₂;

Ce_z

wherein;

RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb;

A is at least one typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr;

D is at least one typical amphoteric element selected from the group consisting of Al, In and Ga;

0≦

x<

0.5;

0≦

y<

0.5;

0<

z<

0.5;

0<

a<

5; and

0<

b<

5.

7. The white semiconductor light emitting device according to claim 5, wherein said yellow phosphor has an absorption peak in the range from about 420 nm to 480 nm and an emission peak in the range from about 530 nm to 570 nm

8. The white semiconductor light emitting device according to claim 5, wherein said semiconductor light emitting diode comprises a substrate and a nitride semiconductor layer on top of the substrate.

9. The white semiconductor light emitting device according to claim 8, wherein said substrate is made of sapphire or silicon carbide.

10. The white semiconductor light emitting device according to claim 8, wherein said nitride semiconductor layer includes a GaN, InGaN, AlGaN or AlGaInN-based semiconductor.

11. The white semiconductor light emitting device according to claim 5, wherein said phosphor coating layer further comprises a zinc selenium-based red phosphor.

12. The white semiconductor light emitting device according to claim 11, wherein the content of said zinc selenium-based red phosphor is 1 to 40 wt % based on the weight of the yellow phosphor.

13. The white semiconductor light emitting device according to claim 5, wherein said transparent resin is a transparent epoxy resin or silicone resin.

17. A liquid crystal display incorporating the white semiconductor light emitting device according to any one of claims 5 to 13 as a back light source.

14. A lead type white semiconductor light emitting device comprising:

a mount lead comprising a lead and a recess portion on said lead;

a blue light emitting LED chip which is disposed in said recess portion, and anode and cathode of which are connected to the lead of said mount lead by metal wires;

a phosphor coating layer filled inside said recess portion to cover said LED chip; and

a casing that seals the mount lead excluding lower portions of said mount lead, said LED chip and phosphor coating layer;

wherein said phosphor coating layer comprises a transparent resin and a terbium borate-based yellow phosphor represented by the following general formula;

(Tb_1-x-y-zRe_xA_y)₃D_aB_bO₁₂;

Ce_z

wherein;

RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb;

A is at least one typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr;

D is at least one typical amphoteric element selected from the group consisting of Al, In and Ga;

0≦

x<

0.5;

0≦

y<

0.5;

0<

z<

0.5;

0<

a<

5; and

0<

b<

5.

15. A surface mount type white semiconductor light emitting device of an injection-molded reflector type comprising:

a casing having a recess portion at a top thereof and equipped with metal terminals;

a blue light emitting LED chip which is located in said recess portion, and anode and cathode of which are connected to said metal terminals by metal wires; and

a phosphor coating layer filled inside said recess portion to cover said LED chip;

wherein said phosphor coating layer comprises a transparent resin and a terbium borate-based yellow phosphor represented by the following general formula;

(Tb_1-x-y-zRe_xA_y)₃D_aB_bO₁₂;

Ce_z

wherein;

RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb;

A is at least one typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr, D is at least one typical amphoteric element selected from the group consisting of Al, In and Ga;

0≦

x<

0.5;

0≦

y<

0.5;

0<

z<

0.5;

0<

a<

5; and

0<

b<

5.

16. A surface mount type white semiconductor light emitting device of the PCB (printed circuit board) type comprising a blue LED chip and a phosphor coating layer on a PCB layer, wherein said phosphor coating layer comprises a terbium borate-based yellow phosphor represented by the following general formula:

(Tb_1-x-y-zRe_xA_y)₃D_aB_bO₁₂;

Ce_z

wherein;

RE is at least one rare earth element selected from the group consisting of Y, Lu, Sc, La, Gd, Sm, Pr, Nd, Eu, Dy, Ho, Er, Tm and Yb;

A is at least one typical metal element selected from the group consisting of Li, Na, K, Rb, Cs and Fr;

D is at least one typical amphoteric element selected from the group consisting of Al, In and Ga;

0≦

x<

0.5;

0≦

y<

0.5;

0<

z<

0.5;

0<

a<

5; and

0<

b<

5.