Phosphor for light sources, and associated light source

• US 6,552,487 B1
• Filed: 10/23/2000
• Issued: 04/22/2003
• Est. Priority Date: 10/27/1999
• Status: Expired due to Term

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen MbH (Siemens AG)
• Inventors: Zwaschka, Franz, Ellens, Andries
• Primary Examiner(s): Patel, Ashok
• Application Number:
  US09/694,635
• Time in Patent Office: 911 Days
• Field of Search: 313/502, 313/503, 313/504, 313/468, 313/486, 313/487, 252/301.4 R, 257/11, 257/78, 257/102, 257/103
• US Class Current: 313/503
• CPC Class Codes: C09K 11/7769 Oxides C09K11/7768 takes precedence
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

The phosphor according to the invention has the following composition:

(RE_1−x−yPr_xCe_y)₃(Al,Ga)₅O₁₂,

where

RE=Y, Sc, Tb, Gd, La and/or Lu;

0.00001<x<0.05;

0.01<y<0.2.

Claims

1. Phosphor for excitation by a light-emitting radiation source, the emission from which lies in the short-wave optical spectral region between 420 and 490 nm, having a garnet structure A₃B₅O₁₂, which is activated with Ce, the second component B representing at least one of the elements Al and Ga, wherein the first component A contains a rare earth RE selected from the group consisting of Y, Tb, La and/or Lu, with a proportion of at most 5 mol %, of A being replaced by praseodymium, praseodymium acting as second activator in addition to Ce according to the formula A₃B₅O₁₂:

(Ce,Pr).

2. The phosphor as claimed in claim 1, wherein the first component A contains in addition Gd and/or Sc as a non-luminous constituent of the host lattice.

3. The phosphor as claimed in claim 1, wherein the first component A is, more than 75 mol % yttrium.

4. The phosphor as claimed in claim 3, wherein the first component, in addition to Y and/or Lu, uses amounts of Tb, Sc, Gd and/or La.

5. The phosphor as claimed in claim 3 wherein the phosphor contains 0.1 to 20 mol % Tb.

6. The phosphor as claimed in claim 1, wherein the phosphor can be excited by radiation in the range from 430 to 470 nm.

7. The phosphor as claimed in claim 6 wherein the exciting radiation has a peak wavelength in the range from 440 to 465 nm.

8. The phosphor as claimed in claim 1, wherein a garnet of the overall structure

9. The phosphor as claimed in claim 1, wherein the second component B contains both Al and Ga.

10. The phosphor as claimed in claim 9 wherein the second component additionally contains In.

11. The phosphor as claimed in claim 1, wherein the amount of the Pr and the condition of the host lattice are so selected that the two lines of the Pr at 609 and 611 nm appear in the emission spectrum.

12. The phosphor as claimed in claim 11, wherein the amount of the Pr is selected to be so low as for the two lines of the Pr at 609 and 611 nm to appear separately in the emission spectrum.

13. The phosphor as claimed in claim 11, wherein the amount of the Pr is selected to be so high as for the Pr line at 637 nm to appear in the emission spectrum.

14. The phosphor of claim 11 wherein the amount of Pr is higher than 0.02 mol %.

15. The light source as claimed in claim 12, wherein the radiation is converted into longer-wave radiation by means of two phosphors as claimed in claim 1.

16. The light source as claimed in claim 12, characterized in that it has the following features for realizing a white-emitting LED:

a light producing device, in particular a blue-emitting light-emitting diode which emits primary radiation;

a wavelength conversion device which is connected to the light producing device, the primary radiation penetrating into the wavelength conversion device and there being partly converted into the secondary longer-wave radiation, the wavelength conversion device comprising at least one, of the phosphors as in claims 1 to 8, the wavelength conversion device further including a casting mass in which the phosphor(s) is (are) dispersed.

17. The light source as claimed in claim 12, wherein the primary radiation emitted is in the wavelength range from 430 to 470 nm.

18. The light source as claimed in claim 12, wherein the primary radiation source used is a blue-emitting light-emitting diode, based on InGaN, the peak emission of which is in the range from 440 to 465 nm.

19. A light source which primarily emits radiation in the short-wave range of the optical spectral region in the wavelength range from 420 to 490 nm, this radiation being partially or completely converted into secondary longer-wave radiation by means of a phosphor, as claimed in claim 1.

20. The light source as claimed in claim 19 wherein a single phosphor as claimed in claim 1 is used.

21. The phosphor as claimed in claim 1 wherein at most 1 mol % of A is replaced by praseodymium.

22. The phosphor as claimed in claim 1 wherein the amount Pr is lower than 0.3 mol %.

23. A phosphor having the general formula:

24. The phosphor of claim 23 wherein 0.0005≦

x≦

0.01.

25. The phosphor of claim 23 wherein 0.0005≦

x≦

0.005.

26. The phosphor of claim 23 wherein the phosphor has narrow band red emissions at 609 and 611 nm.

27. The phosphor of claim 26 wherein the phosphor has an additional narrow band red emission at 637 nm.

28. The phosphor of claim 27 wherein the 637 nm emission comprises at least 10% of the contribution of the 609 nm and 611 nm emissions.

29. A phosphor having the general formula (Y_0.959Ce_0.04Pr_0.001)₃Al₅O₁₂.