Phosphor converted light emitting device

• US 6,717,353 B1
• Filed: 10/14/2002
• Issued: 04/06/2004
• Est. Priority Date: 10/14/2002
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.), Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Sorce, Gerry, Schmidt, Peter J., Mueller-Mach, Regina B., Mueller, Gerd O., Jüstel, Thomas
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): HARPER, HOLLY R
• Application Number:
  US10/272,150
• Time in Patent Office: 540 Days
• Field of Search: 313/501, 313/502, 313/503, 313/485, 313/486, 313/487, 252/301.4 R, 252/301.4 S
• US Class Current: 313/501
• 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 11/7738 with alkaline earth metals
• 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
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A device includes a semiconductor light emitting device and a wavelength-converting material comprising Sr—SiON:Eu²⁺. The Sr—SiON:Eu²⁺ wavelength-converting material absorbs light emitted by the light emitting device and emits light of a longer wavelength. The Sr—SiON:Eu²⁺ wavelength-converting material may be combined with other wavelength-converting materials to make white light. In some embodiments, the Sr—SiON:Eu²⁺ wavelength-converting layer is combined with a red-emitting wavelength-converting layer and a blue light emitting device to generate emission in colors, which are not achievable by only mixing primary and secondary wavelengths. In some embodiments, the Sr—SiON:Eu²⁺ wavelength-converting layer is combined with a red-emitting wavelength-converting layer, a blue-emitting wavelength-converting layer, and a UV light emitting device.

Claims

1. A device comprising:

a semiconductor light emitting device capable of emitting light of a first wavelength; and

a first wavelength-converting material comprising Sr—

SiON;

Eu²⁺, the first wavelength-converting material disposed to absorb light of the first wavelength;

wherein the first wavelength-converting material absorbs light of the first wavelength and emits light of a second wavelength longer than the first wavelength.

2. The device of claim 1 wherein the first wavelength ranges from blue to UV.

3. The device of claim 1 wherein the second wavelength is green.

4. The device of claim 1 further comprising a second wavelength-converting material, wherein the second wavelength-converting material absorbs light of one of the first wavelength and the second wavelength, and emits light of a third wavelength longer than the second wavelength.

5. The device of claim 4 wherein the third wavelength is red.

6. The device of claim 4 wherein the second wavelength-converting material is selected from the group consisting of (Sr₁₋

a−

b−

cBa_bCa_c)₂Si₅N₈;

Eu_a (a=0.002-0.2, b=0.0-1.0, c=0.0-1.0);

(Ca<sub>1−

x−

a</sub>Sr_x)S;

Eu_a (a=0.0005 . . . 0.01, x=0.0-1.0);

Ca<sub>1−

a</sub>SiN₂;

Eu_a (a0.002-0.2); and

(Ba<sub>1−

x−

a</sub>Ca_x)Si₇N₁₀;

Eu_a (a=0.002-0.2, x=0.0-0.25).

7. The device of claim 4 wherein the first wavelength is blue.

8. The device of claim 4 further comprising a third wavelength-converting material, wherein the third wavelength-converting material absorbs light of the first wavelength and emits light of a fourth wavelength longer than the first wavelength and shorter than the second wavelength.

9. The device of claim 8 wherein the first wavelength is UV, the second wavelength is green, the third wavelength is red, and the fourth wavelength is blue.

10. The device of claim 8 wherein the third wavelength-converting material is selected from the group consisting of (Sr₁₋

x−

aBa_x)₃MgSi₂O₈;

Eu_a (a=0.002-0.2, x=0.0-1.0);

(Sr<sub>1−

x−

a</sub>Ba_x)₂P₂O₇;

Eu_a (a=0.002-0.2, x=0.0-1.0);

(Sr<sub>1−

x'"'"'a</sub>Ba_x)₄Al₁₄O₂₅;

Eu_a (a=0.002-0.2, x=0.0-1.0);

La<sub>1−

a</sub>Si₃N₅;

Ce_a (a=0.002-0.5);

(Y<sub>1−

a</sub>)₂SiO₅;

Ce_a (a=0.002-0.5); and

(Ba<sub>1−

x−

a</sub>Sr_x)MgAl₁₀O₁₇;

Eu_a (a=0.01-0.5, x=0.0-0.5).

11. The device of claim 8 wherein the amounts of first wavelength-converting material, second wavelength-converting material, and third wavelength-converting material are selected to prevent light of the first wavelength from escaping the device.

12. The device of claim 1 further comprising a filter material capable of absorbing light of the first wavelength.

13. The device of claim 1 wherein the second wavelength comprises a centroid wavelength of 556 nm.

14. The device of claim 1 wherein the light emitting device is a III-nitride light emitting diode.

15. The device of claim 1 wherein the first wavelength-converting material is coated on a top surface and a side surface of the light emitting device.

16. The device of claim 1 further comprising:

a pair of leads electrically connected to the light emitting device; and

a lens disposed over the light emitting device.

17. The device of claim 16 wherein the first wavelength-converting material is dispersed in an encapsulant disposed between the light emitting device and the lens.

18. The device of claim 16 wherein the light emitting device is mounted such that light is extracted from the light emitting device through a transparent substrate.

19. A device comprising:

a III-nitride light emitting diode;

a green emitting phosphor comprising Sr—

SiON;

Eu²⁺; and

a red emitting phosphor;

wherein the green emitting phosphor and the red emitting phosphor are disposed over the III-nitride light emitting diode.

20. The device of claim 19 wherein the red emitting phosphor is selected from the group consisting of (Sr₁₋

a−

b−

cBa_bCa_c)₂Si₅N₈;

Eu_a (a=0.002-0.2, b=0.0-1.0, c=0.0 -1.0);

(Ca<sub>1−

x−

a</sub>Sr_x)S;

Eu_a (a=0.0005 . . . 0.01, x=0.0-1.0);

Ca<sub>1−

a</sub>SiN₂;

Eu_a (a=0.002-0.2); and

(Ba<sub>1−

x−

a</sub>Ca_x) Si₇N₁₀;

Eu_a (a=0.002-0.2, x=0.0-0.25).

21. The device of claim 19 further comprising a blue emitting phosphor disposed over the III-nitride light emitting diode.

22. The device of claim 21 wherein the blue emitting phosphor is selected from the group consisting of (Sr₁₋

x−

aBa_x)₃MgSi₂O₈;

Eu_a (a=0.002-0.2, x=0.0-1.0);

(Sr<sub>1−

x−

a</sub>Sr_x)₂P₂O₇;

Eu_a (a=0.002-0.2, x=0.0-1.0);

(Sr<sub>1−

x−

a</sub>Ba_x)₄Al₁₄O₂₅;

Eu_a (a=0.002-0.2, x=0.0-1.0);

La<sub>1−

a</sub>Si₃N₅;

Ce_a (a=0.002-0.5);

(Y<sub>1−

a</sub>)₂SiO₅;

Ce_a (a=0.002-0.5); and

(Ba<sub>1−

x−

a</sub>Sr_x) MgAl₁₀O₁₇;

Eu_a (a=0.01-0.5, x=0.0-0.5).

23. The device of claim 19 wherein the green emitting phosphor absorbs light emitted by the blue emitting phosphor and emits green light.