Methods of determining and making red nitride compositions

• US 8,814,621 B2
• Filed: 06/03/2011
• Issued: 08/26/2014
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Seibel, Harry A. II
• Primary Examiner(s): COUGHLIN, ANDREW J
• Application Number:
  US13/153,155
• Publication Number:
  US 20120306355A1
• Time in Patent Office: 1,180 Days
• Field of Search: 313/503, 445/23, 702/189, 252/301.4 R
• US Class Current: 445/23
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

Provided according to embodiments of the invention are methods of making a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor composition that include selecting a relative color point; determining Eu and Sr concentrations based on predetermined values to obtain the selected relative color point; and making the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor having the determined Eu and Sr concentrations. Also provided are methods for determining concentrations of Sr and Eu in a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor that will achieve a relative color point. Related computer products are also disclosed.

Claims

1. A method of making a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor composition comprising:

selecting a relative color point in a three-dimensional space comprising a relative color axis, a relative brightness axis and a third axis comprising one of;

a Sr/Eu axis, a Sr concentration axis or a Eu concentration axis;

determining, based on a predetermined region in the three-dimensional space, a range of Sr to Eu ratios, a range of Sr concentrations, and/or a range of Eu concentrations to obtain the selected relative color point; and

making a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor composition having one of the Sr to Eu ratios, one of the Sr concentrations, and/or one of the Eu concentrations.

2. The method of claim 1, further comprising selecting a relative brightness in the three-dimensional space before determining the range of Sr to Eu ratios, the range of Sr concentrations, or the range of Eu concentrations, and wherein the determining comprises obtaining the selected relative color point and the selected relative brightness.

3. The method of claim 2, wherein the selected relative color point is in a range of −

0.005 to 0.02.

4. The method of claim 2, wherein the selected relative brightness is in a range of 0.75 to 1.75.

5. The method of claim 2, wherein the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor composition absorbs light at a wavelength in a range of 350 nm and 530 nm and emits peak frequencies at a wavelength in a range of 620 nm to 660 nm.

6. The method of claim 2, wherein the Sr to Eu ratio in the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor is in a range of 25 to 300.

7. The method of claim 2, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.50 to 0.99 and y is in a range of 0.001 to 0.025.

8. The method of claim 2, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.70 to 0.99 and y is in a range of 0.001 to 0.025.

9. The method of claim 2, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.50 to 0.99 and y is less than 0.013.

10. The method of claim 2, wherein the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor composition is present in particulate form and at least 50% of the particles are elongated.

11. The method of claim 1, wherein the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor comprises at least 1% by weight of silicon aluminum oxynitride.

12. The method of claim 1, wherein the third axis is the Sr/Eu axis, and the predetermined region in the three-dimensional space spans Sr to Eu ratios of from 25 to 300 along the Sr/Eu axis.

13. The method of claim 1, wherein the third axis is the Sr concentration axis, and the predetermined region in the three-dimensional space spans Sr concentrations of from 0.5 to 0.99.

14. The method of claim 1, wherein the third axis is the Eu concentration axis, and the predetermined region in the three-dimensional space spans Eu concentrations of from 0.001 to 0.025.

15. A method for determining concentrations of Sr and Eu in a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor that will achieve a relative color point, the method comprising:

selecting a relative color point in a three-dimensional space comprising a relative color axis, a relative brightness axis and a third axis comprising one of;

a Sr/Eu axis, a Sr concentration axis or a Eu concentration axis; and

determining, based on a predetermined region in the three-dimensional space, a range of Sr to Eu ratios, a range of Sr concentrations, and/or a range of Eu concentrations to obtain the selected relative color point for a Ca_1-x-ySr_xEu_yAlSiN₃ phosphor.

16. The method of claim 15, further comprising selecting a relative brightness in the three-dimensional space before determining the range of Sr to Eu ratios, the range of Sr concentrations, or the range of Eu concentrations, and wherein the determining comprises obtaining the selected relative color point and the selected relative brightness.

17. The method of claim 16, wherein the selected relative color point is in a range of −

0.005 to 0.02.

18. The method of claim 16, wherein the selected relative brightness is in a range of 0.75 to 1.75.

19. The method of claim 16, wherein the Sr to Eu ratio in the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor is in a range of 25 to 300.

20. The method of claim 16, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.50 to 0.99 and y is in a range of 0.001 to 0.025.

21. The method of claim 16, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.70 to 0.99 and y is in a range of 0.001 to 0.025.

22. The method of claim 16, wherein for the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor, x is in a range of 0.50 to 0.99 and y is less than 0.013.

23. The method of claim 16, wherein the Ca_1-x-ySr_xEu_yAlSiN₃ phosphor comprises at least 1% by weight of silicon aluminum oxynitride.

24. The method of claim 15, wherein the third axis is the Sr/Eu axis, and the predetermined region in the three-dimensional space spans Sr to Eu ratios of from 25 to 300 along the Sr/Eu axis.

25. The method of claim 15, wherein the third axis is the Sr concentration axis, and the predetermined region in the three-dimensional space spans Sr concentrations of from 0.5 to 0.99.

26. The method of claim 15, wherein the third axis is the Eu concentration axis, and the predetermined region in the three-dimensional space spans Eu concentrations of from 0.001 to 0.025.