Phosphor Composition

• US 10,266,767 B2
• Filed: 08/11/2016
• Issued: 04/23/2019
• Est. Priority Date: 11/17/2008
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Collins, Brian T., Hussell, Christopher P., Emerson, David T., Le Toquin, Ronan P.
• Primary Examiner(s): Branch, Catherine S
• Application Number:
  US15/234,433
• Publication Number:
  US 20160348000A1
• Time in Patent Office: 985 Days
• Field of Search: None
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3869 Aluminium oxynitrides, e.g. AlON, sialon
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 35/58 based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides containing free binder metal C22C29/00
• CPC Class Codes: C04B 35/581 based on aluminium nitride
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/591 obtained by reaction sintering
• CPC Class Codes: C04B 35/593 obtained by pressure sintering
• CPC Class Codes: C04B 35/5935 obtained by gas pressure sintering
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7728 containing europium
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A method is disclosed for forming a blended phosphor composition. The method includes the steps of firing precursor compositions that include europium and nitrides of at least calcium, strontium and aluminum, in a refractory metal crucible and in the presence of a gas that precludes the formation of nitride compositions between the nitride starting materials and the refractory metal that forms the crucible. The resulting compositions can include phosphors that convert frequencies in the blue portion of the visible spectrum into frequencies in the red portion of the visible spectrum.

Claims

1. A phosphor composition comprising:

Ca_1-x-ySr_xEu_yAlSiN₃, where 0<

x<

1 and 0<

y<

1; and

silicon oxynitride in an amount of at least 1% by weight.

2. The phosphor composition of claim 1, wherein the silicon oxynitride comprises silicon aluminum oxynitride.

3. The phosphor composition of claim 2, wherein the silicon aluminum oxynitride comprises Si₂Al₄O₄N₄.

4. The phosphor composition of claim 1, wherein x is between 0.50 and 0.70.

5. The phosphor composition of claim 4, wherein x is between about 0.55 and 0.67.

6. The phosphor composition of claim 1, wherein y is between about 0.013 and 0.017.

7. The phosphor composition of claim 1, further comprising aluminum nitride.

8. The phosphor composition of claim 1, wherein the phosphor composition absorbs frequencies of between about 430 and 480 nanometers and emits peak frequencies of between about 530 and 750 nanometers.

17. The phosphor composition of claim 1, wherein the phosphor composition is in the form of particles.

18. The phosphor composition of claim 17, wherein the particles comprise pulverized particles.

9. A phosphor composition comprising:

a first phase comprising Ca_1-x-ySr_xEu_yAlSiN₃, where 0<

x<

1 and 0<

y<

1; and

a second phase comprising silicon aluminum oxynitride.

10. The phosphor composition of claim 9, wherein the silicon aluminum oxynitride comprises Si₂Al₄O₄N₄.

11. The phosphor composition of claim 9, wherein the silicon aluminum oxynitride is present in an amount of at least 1% by weight.

12. The phosphor composition of claim 9, further comprising a third phase comprising aluminum nitride.

13. The phosphor composition of claim 9, wherein x is between 0.50 and 0.70.

14. The phosphor composition of claim 13, wherein x is between about 0.55 and 0.67.

15. The phosphor composition of claim 9, wherein y is between about 0.013 and 0.017.

16. The phosphor composition of claim 9, wherein the phosphor composition absorbs frequencies of between about 430 and 480 nanometers and emits peak frequencies of between about 530 and 750 nanometers.

19. The phosphor composition of claim 9, wherein the phosphor composition is in the form of particles.

20. The phosphor composition of claim 19, wherein the particles comprise pulverized particles.