Device and method for emitting output light using quantum dots and non-quantum fluorescent material

• US 20060081862A1
• Filed: 10/14/2004
• Published: 04/20/2006
• Est. Priority Date: 10/14/2004
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Tan, Kheng Leng, Chua, Janet Bee Yin, Ng, Kee Yean, Pan, Kok Chin, Baroky, Tajul Arosh
• Granted Patent: US 7,102,152 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A device and method for emitting output light utilizes both quantum dots and non-quantum fluorescent material to convert at least some of the original light emitted from a light source of the device to longer wavelength light to change the color characteristics of the output light. The device can be used to produce broad-spectrum color light, such as white light.

Claims

1. A device for emitting output light, said device comprising:

a light source that emits original light; and

a wavelength-shifting region optically coupled to said light source to receive said original light, said wavelength-shifting region including at least one type of quantum dots to convert some of said original light to first converted light, said wavelength-shifting region further including non-quantum fluorescent material to convert some of said original light to second converted light, said first converted light and said second converted light being components of said output light.

2. The device of claim 1 wherein said non-quantum fluorescent material includes phosphor particles.

3. The device of claim 2 wherein said phosphor particles have a silica coating.

4. The device of claim 2 wherein said non-quantum fluorescent material includes a phosphor selected from a group consisting of Garnet-based phosphor, Silicate-based phosphor, Orthosilicate-based phosphor, Thiogallate-based phosphor, Sulfide-based phosphor and Nitride-based phosphor.

5. The device of claim 1 wherein said quantum dots have a coating of selected material.

6. The device of claim 5 wherein said coating of said quantum dots includes organic caps, quantum dot shells or caps made of glass material.

7. The device of claim 1 wherein said quantum dots includes one of CdS, CdSe, CdTe, CdPo, ZnS, ZnSe, ZnTe, ZnPo, MgS, MgSe, MgTe, PbSe, PbS, PbTe, HgS, HgSe, HgTe, Cd(S_1-xSe_x), BaTiO₃, PbZrO₃, PbZr_zTi_1-zO₃, Ba_xSr_1-x TiO₃, SrTiO₃, LaMnO₃, CaMnO₃ and La_1-xCa_xMnO₃.

8. The device of claim 1 wherein said wavelength-shifting region includes silicone, glass, epoxy or a hybrid material of silicone and epoxy.

9. The device of claim 1 wherein said wavelength-shifting region includes at least one of diffusing particles, ultraviolet inhibitor and adhesion promoter, or any combination thereof.

10. The device of claim 1 wherein said light source includes at least one light emitting diode die.

11. A method for emitting output light, said method comprising:

generating original light;

receiving said original light, including converting some of said original light to first converted light using at least one type of quantum dots and converting some of said original light to second converted light using non-quantum fluorescent material; and

emitting said first converted light and said second converted light as components of said output light.

12. The method of claim 11 wherein said non-quantum fluorescent material includes phosphor particles.

13. The method of claim 12 wherein said phosphor particles have a silica coating.

14. The method of claim 12 wherein said non-quantum fluorescent material includes a phosphor selected from a group consisting of Garnet-based phosphor, Silicate-based phosphor, Orthosilicate-based phosphor, Thiogallate-based phosphor, Sulfide-based phosphor and Nitride-based phosphor.

15. The method of claim 11 wherein said quantum dots have a coating of selected material.

16. The method of claim 15 wherein said coating of said quantum dots includes organic caps, quantum dot shells or caps made of glass material.

17. The method of claim 11 wherein said quantum dots includes one of CdS, CdSe, CdTe, CdPo, ZnS, ZnSe, ZnTe, ZnPo, MgS, MgSe, MgTe, PbSe, PbS, PbTe, HgS, HgSe, HgTe, Cd(S_1-xSe_x), BaTiO₃, PbZrO₃, PbZr_zTi_1-zO₃, Ba_xSr_1-x TiO₃, SrTiO₃, LaMnO₃, CaMnO₃ and La_1-xCa_xMnO₃.

18. A device for emitting output light, said device comprising:

a light source that emits original light; and

a wavelength-shifting region optically coupled to said light source to receive said original light, said wavelength-shifting region including at least one type of quantum dots to convert some of said original light to first converted light, said wavelength-shifting region further including a plurality of phosphor particles to convert some of said original light to second converted light, said first converted light and said second converted light being components of said output light.

19. The device of claim 18 wherein said quantum dots or said phosphor particles have a coating of selected material.

20. The device of claim 19 wherein said coating includes organic caps, quantum dot shells or caps made of glass material on said quantum dots.