Fluorescent substance, light emitting device, surface light source device, display device and illuminating device

Patent metadata

Field	Value
Publication number	US-9127203-B2
Application number	US-201113578779-A
Country	US
Kind code	B2
Filing date	Feb 11, 2011
Priority date	Feb 12, 2010
Publication date	Sep 8, 2015
Grant date	Sep 8, 2015

Abstract

There is provided a phosphor having a β-type Si 3 N 4 crystal structure including oxynitride expressed by an empirical formula Si 6-z Al z O z N 8-z :Eu a ,M b , M being at least one selected from among strontium (Sr) and barium (Ba), an amount (a) of europium (Eu) ranging from 0.1 to 5 mol %, an amount (b) of M ranging from 0.1 to 10 mol %, and a composition rate (z) of aluminum (Al) satisfying 0.1<z<1, and the phosphor emitting light having a peak wavelength ranging from 500 to 550 nm when excitation light is irradiated thereto.

First claim

The invention claimed is:

1. A phosphor having a β-type Si 3 N 4 crystal structure and including oxynitride expressed by an empirical formula Si 6-z Al z O z N 8-z :Eu a ,M b ,
M being at least one selected from among strontium (Sr) and barium (Ba), an amount (a) of europium (Eu) ranging from 0.1 to 5 mol %, an amount (b) of M ranging from 0.1 to 10 mol %, and a composition rate (z) of aluminum (Al) satisfying 0.1<z<1, and
the phosphor emitting light having a peak wavelength ranging from 500 to 550 in when excitation light is irradiated thereto,
wherein M is a dopant of the phosphor and is disposed in an interstitial space of the phosphor.

2. The phosphor of claim 1 , wherein the excitation light has a peak wavelength ranging from 300 to 480 nm.

3. The phosphor of claim 2 , wherein a peak wavelength of the light emitted from the phosphor is 540 nm or less when the phosphor is irradiated by the excitation light.

4. The phosphor of claim 1 , wherein when the light emitted from the phosphor due to the irradiated excitation light is represented as an (x, y) value in the CIE 1931 chromaticity coordinates, x and y respectively satisfy x≦0.336 and y≧0.637.

5. The phosphor of claim 1 , wherein in the CIE 1931 chromaticity coordinates of the light emitted from the phosphor, an amount of change of y is −0.0065 or less, and the amount of change of y is defined as y2−y1 when a value of y is y1 in the CIE 1931 chromaticity coordinates, measured from the light emitted initially on the condition of driving a blue light emitting diode having the phosphor applied thereto at 3.3 V, 120 mA, and a value of y is y2 in the CIE 1931 chromaticity coordinates, measured from the light emitted after the above driving condition is continuously performed for 24 hours at 85° C.

6. The phosphor of claim 1 , wherein M is strontium (Sr).

7. The phosphor of claim 6 , wherein the amount (a) of the strontium (Sr) ranges from 0.5 to 3 mol %.

8. The phosphor of claim 7 , wherein the amount (a) of the strontium (Sr) ranges from 1 to 1.5 mol %.

9. The phosphor of claim 1 , wherein the composition rate (z) of aluminum (Al) ranges from 0.1 to 0.3 mol %.

10. The phosphor of claim 1 , wherein the amount (b) of europium (Eu) ranges from 0.9 to 3 mol %.

11. The phosphor of claim 1 , wherein M contains both barium (Ba) and strontium (Sr).

12. The phosphor of claim 1 , wherein a value D50 in a grain size of the phosphor powder ranges from 14.5 to 18.5 μm.

13. The phosphor of claim 1 , wherein the phosphor is an activator and further contains at least one element selected from a group consisting of lithium (Li), sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca).

14. A surface light source apparatus using the phosphor according to claim 1 , as a wavelength conversion material.

15. A surface light source apparatus comprising:
a light guide plate; and
an LED light source module disposed on at least one side of the light guide plate to provide light to the interior of the light guide plate,
the LED light source module including a circuit board, and a plurality of white light emitting devices mounted on the circuit board and using the phosphor according to claim 1 as a wavelength conversion material.

16. A display apparatus comprising:
an image display panel displaying an image; and
a backlight unit having the surface light source apparatus according to claim 15 to provide light to the image display panel.

17. A display apparatus using the phosphor according to claim 1 , as a wavelength conversion material.

18. An illumination device using the phosphor according to claim 1 as a wavelength conversion material.

19. An illumination device comprising:
an LED light source module; and
a diffusion sheet disposed at an upper part of the LED light source module and uniformly diffusing light input from the LED light source module,
the LED light source module including a circuit board and a plurality of white light emitting devices mounted on the circuit board and using the phosphor according to claim 1 as a wavelength conversion material.

20. A method of manufacturing an oxynitride phosphor having β-type Si 3 N 4 crystal structure expressed by an empirical formula Si 6-z ,Al z O z N 8-z :Eu a ,M b , M being at least one selected from among strontium (Sr) and barium (Ba), an amount (a) of europium (Eu) ranging from 0.1 to 5 mol %, an amount (b) of M ranging from 0.1 to 10 mol %, and a composition rate (z) of aluminum (Al) satisfying 0.1<z<1, the method comprising:
weighing raw materials including an Si-containing oxide or nitride, an Al-containing oxide or nitride, an Eu-containing compound and an M-containing compound;
preparing a primary mixture by mixing the raw materials, excepting the M-containing compound;
primarily firing the primary mixture and grinding the primarily fired mixture;
preparing a secondary mixture by mixing the M-containing compound with the ground mixture; and
secondarily firing the secondary mixture and grinding the secondarily fired mixture.

21. The method of claim 20 , wherein the primary firing process is performed in a firing temperature range of 1850 to 2300° C., and the secondary tiring process is performed at a temperature lower than that of the primary firing process.

22. The method of claim 20 , wherein the primary and secondary firing processes are performed under an atmosphere of nitrogen gas or a mixture of nitrogen and hydrogen gasses.

23. The method of claim 20 , wherein the M-containing compound is strontium (Sr).

24. The method of claim 23 , wherein the amount (a) of the strontium (Sr) ranges from 0.5 to 3 mol %.

25. The method of claim 24 , wherein the amount (a) of the strontium (Sr) ranges from 1 to 1.5 mol %.

26. The method of claim 20 , wherein the composition rate (z) of aluminum (Al) ranges from 0.1 to 0.3 mol %.

27. The method of claim 20 , wherein the amount (b) of europium (Eu) ranges from 0.9 to 3 mol %.

28. The method of claim 20 , wherein the M-containing compound contains both a barium (Ba)-containing compound and a strontium (Sr)-containing compound.

29. The method of claim 20 , wherein the preparing of the secondary mixture includes adding a compound containing at least one element selected from a group consisting of Li, Na, K, Mg and Ca, as an activator together with the M-containing compound.

30. A white light emitting device comprising:
a light emitting diode (LED) chip emitting excitation light;
a green phosphor disposed around the LED chip to wavelength-convert at least a portion of the excitation light and including the phosphor according to claim 1 ; and
at least one light emitting element emitting light of a wavelength different from a wavelength of the LED chip and a wavelength of the green phosphor, the at least one light emitting element being at least one of an additional LED chip and a different type of phosphor.

31. The device of claim 30 , wherein the LED chip is an LED chip emitting ultraviolet light, or an LED chip emitting visible light having a peak wavelength of 470 nm or more.

32. The device of claim 30 , wherein the LED chip is a blue LED chip having a peak wavelength ranging from 430 nm to 470 nm, and the at least one light emitting element includes a red phosphor.

33. The device of claim 32 , wherein a

Assignees

• Yoon Chang Bun
• Won Hyong Sik
• Yoon Chul Soo
• Samsung Electronics Co Ltd

Inventors

• Yoon Chang Bun
• Won Hyong Sik
• Yoon Chul Soo

Classifications

• C09K11/77348 Primary

  Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides · CPC title

• C04B35/597 Primary

  based on silicon oxynitride, {e.g. SIALONS} · CPC title

• H10H20/822

  Materials of the light-emitting regions · CPC title

• C04B2235/3865

  Aluminium nitrides · CPC title

• C04B2235/3213

  Strontium oxides or oxide-forming salts thereof · CPC title