White light emitting device and white light source module using the same

• US 7,959,312 B2
• Filed: 04/21/2008
• Issued: 06/14/2011
• Est. Priority Date: 12/05/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung LED Co., Ltd. (Samsung Electronics Co. Ltd.)
• Inventors: Jeong, Young June, Kim, Ho Yeon, Han, Seong Yeon, Park, Young Sam, Yoo, Chul Hee, Kim, Hyung Suk, Hahm, Hun Joo
• Primary Examiner(s): Sember; Thomas M
• Application Number:
  US12/081,726
• Publication Number:
  US 20080265269A1
• Time in Patent Office: 1,149 Days
• Field of Search: 362/293, 362/230, 362/231, 362/267, 362/310, 362/810, 362 971- 973, 362/84, 257/89, 257/98, 257/E33.01, 257/E33.067, 313/498, 313/501, 313/503
• US Class Current: 362/84
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/77347 Silicon Nitrides or Silicon Oxynitrides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A white light emitting device including: a blue light emitting diode chip having a dominant wavelength of 443 to 455 nm; a red phosphor disposed around the blue light emitting diode chip, the red phosphor excited by the blue light emitting diode chip to emit red light; and a green phosphor disposed around the blue light emitting diode chip, the green phosphor excited by the blue light emitting diode chip to emit green light, wherein the red light emitted from the red phosphor has a color coordinate falling within a space defined by four coordinate points (0.5448, 0.4544), (0.7079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) based on the CIE 1931 chromaticity diagram, and the green light emitted from the green phosphor has a color coordinate falling within a space defined by four coordinate points (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030) based on the CIE 1931 color chromaticity diagram.

Claims

1. A white light source module comprising:

a circuit board;

a blue light emitting diode chip disposed on the circuit board;

a red phosphor disposed around the blue light emitting diode chip, the red phosphor excited by the blue light emitting diode chip to emit red light; and

a green phosphor disposed around the blue light emitting diode chip, the green phosphor excited by the blue light emitting diode chip to emit green light,

wherein the red light emitted from the red phosphor has a color coordinate falling within a space defined by four coordinate points (0.5448, 0.4544), (0.7079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) based on the CIE 1931 color chromaticity diagram, and the green light emitted from the green phosphor has a color coordinate falling within a space defined by four coordinate points (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030) based on the CIE 1931 color chromaticity diagram.

2. The white light source module of claim 1, wherein the blue light emitting diode chip has a full width at half-maximum of 10 to 30 nm, the green phosphor has a full width at half-maximum of 30 to 100 nm and the red phosphor has a full width at half-maximum of 50 to 200 nm.

3. The white light source module of claim 1, wherein the blue light emitting diode chip has a dominant wavelength of 443 to 455 nm, and the blue light emitting diode chip has a full width at half-maximum of 10 to 30 nm.

4. The white light source module of claim 1, wherein the red phosphor comprises at least one of CaAlSiN3:

Eu, Ca2Si5N8;

Eu and (Ca,Sr)S;

Eu.

5. The white light source module of claim 1, wherein the green phosphor comprises at least one of A2Si04:

Eu, SrGa2S4;

Eu and β

-SiAION,

wherein A in A2Si04;

Eu comprises at least one of Ba, Sr and Ca.

6. The white light source module of claim 1, further comprising a resin encapsulant encapsulating the blue light emitting diode chip,

wherein the green phosphor and the red phosphor are dispersed in the resin encapsulant.

7. The white light source module of claim 1, further comprising a resin encapsulant encapsulating the blue light emitting device chip,

wherein a first phosphor film comprising one of the green and red phosphors is formed along a surface of the blue light emitting diode chip between the blue light emitting diode chip and the resin encapsulant, and

a second phosphor film comprising the other one of the green and red phosphors is formed on the resin encapsulant.

8. A white light emitting device comprising:

a blue light emitting diode chip having a full width at half-maximum of 10 to 30 nm;

a red phosphor disposed around the blue light emitting diode chip, the red phosphor excited by the blue light emitting diode chip to emit red light; and

a green phosphor disposed around the blue light emitting diode chip, the green phosphor excited by the blue light emitting diode chip to emit green light,

wherein the red light emitted from the red phosphor has a color coordinate falling within a space defined by four coordinate points (0.5448, 0.4544), (0.7079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) based on the CIE 1931 chromaticity diagram, and

the green light emitted from the green phosphor has a color coordinate falling within a space defined by four coordinate points (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030) based on the CIE 1931 color chromaticity diagram.

9. The white light emitting device of claim 8, wherein the blue light emitting diode chip has a dominant wavelength of 443 to 455 nm, the green phosphor has a full width at half-maximum of 30 to 100 nm and the red phosphor has a full width at half-maximum of 50 to 200 nm.

10. The white light emitting device of claim 8, wherein the green phosphor has a full width at half-maximum of 30 to 100 nm and the red phosphor has a full width at half-maximum of 50 to 200 nm.

11. The white light emitting device of claim 8, wherein the red phosphor comprises at least one of CaAISiN3:

Eu, Ca2Si5N8;

Eu and (Ca,Sr)S;

Eu.

12. The white light emitting device of claim 8, wherein the green phosphor comprises at least one of A2Si04:

Eu, SrGa2S4;

Eu and β

-SiAION,

wherein A in A2Si04;

Eu comprises at least one of Ba, Sr and Ca.

13. The white light emitting device of claim 8, further comprising a resin encapsulant encapsulating the blue light emitting diode chip,

wherein the green phosphor and the red phosphor are dispersed in the resin encapsulant.

14. The white light emitting device of claim 8, further comprising a resin encapsulant encapsulating the blue light emitting diode chip,

wherein a first phosphor film comprising one of the green and red phosphors is formed along a surface of the blue light emitting diode chip between the green light emitting device chip and the resin encapsulant, and

a second phosphor film comprising the other one of the green and red phosphors is formed on the resin encapsulant.

15. A display device comprising:

a display panel; and

a backlight unit which emits light to the display panel, the backlight unit comprising a white light source module,

wherein the white light source module comprises;

a circuit board;

a blue light emitting diode chip disposed on the circuit board;

a red phosphor disposed around the blue light emitting diode chip, the red phosphor excited by the blue light emitting diode chip to emit red light; and

a green phosphor disposed around the blue light emitting diode chip, the green phosphor excited by the blue light emitting diode chip to emit green light,

wherein the red light emitted from the red phosphor has a color coordinate falling within a space defined by four coordinate points (0.5448, 0.4544), (0.7079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) based on the CIE 1931 color chromaticity diagram, and the green light emitted from the green phosphor has a color coordinate falling within a space defined by four coordinate points (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030) based on the CIE 1931 color chromaticity diagram.

16. The display device of claim 15 further comprising a driving circuit which drives the backlight unit.

17. The display device of claim 15, wherein the display panel is a liquid crystal panel.

18. A television comprising the display device of claim 15.

19. A display device comprising:

a display panel; and

a backlight unit which emits light to the display panel, the backlight unit comprising a white light emitting device,

wherein the white light emitting device comprises;

a blue light emitting diode chip;

a red phosphor disposed around the blue light emitting diode chip, the red phosphor excited by the blue light emitting diode chip to emit red light; and

a green phosphor disposed around the blue light emitting diode chip, the green phosphor excited by the blue light emitting diode chip to emit green light,

wherein the red light emitted from the red phosphor has a color coordinate falling within a space defined by four coordinate points (0.5448, 0.4544), (0.7079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) based on the CIE 1931 chromaticity diagram, and

the green light emitted from the green phosphor has a color coordinate falling within a space defined by four coordinate points (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030) based on the CIE 1931 color chromaticity diagram.

20. The display device of claim 19, wherein the blue light emitting diode chip has a full width at half-maximum of 10 to 30 nm.

21. The display device of claim 19 further comprising a driving circuit which drives the backlight unit.

22. The display device of claim 19, wherein the display panel is a liquid crystal panel.

23. A television comprising the display device of claim 19.