SOLID STATE LIGHTING DEVICES COMPRISING QUANTUM DOTS

• US 20080173886A1
• Filed: 05/11/2007
• Published: 07/24/2008
• Est. Priority Date: 05/11/2006
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Evident Technologies Incorporated
• Inventors: GILLIES, Jennifer, CHEON, Kwang-Ohk, DUNCAN, David, SOCHA, David, LoCASIO, Michael
• Application Number:
  US11/747,701
• Publication Number:
  US 20080173886A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

Solid state lighting devices containing quantum dots dispersed in polymeric or silicone acrylates and deposited over a light source. Solid state lighting devices with different populations of quantum dots either dispersed in matrix materials or not are also provided. Also provided are solid state lighting devices with non-absorbing light scattering dielectric particles dispersed in a matrix material containing quantum dots and deposited over a light source. Methods of manufacturing solid state lighting devices containing quantum dots are also provided.

Claims

1. A solid state lighting device comprising:

a light source; and

an active layer deposited either directly or indirectly on top of the light source, the active layer comprising one or more populations of quantum dots dispersed in a first matrix material, wherein the first matrix material comprises a polymer or silicone having a plurality of cross-linked acrylate groups.

2. The device of claim 1, wherein the first matrix material is a urethane acrylate, polyacrylate, acrylated silicone, urethane acrylate epoxy mixture, or a combination thereof.

3. The device of claim 1, further comprising:

an encapsulant layer deposited on top of the light source, the encapsulant layer comprising a second matrix material, and

the active layer deposited on top of the encapsulant layer.

4. The device of claim 3, wherein the second matrix material comprises a polyacrylate, acrylated silicone, urethane acrylate, epoxy, silicone, sol-gel, nanoclay, or a combination thereof.

5. The device of claim 1, further comprising another encapsulant layer deposited on top of the active layer, the another encapsulant layer comprising a third matrix material.

6. The device of claim 3, further comprising another encapsulant layer deposited on top of the active layer, the another encapsulant layer comprising a third matrix material.

7. The device of claim 5, wherein the third matrix material comprises a polyacrylate, acrylated silicone, urethane acrylate, epoxy, silicone, sol-gel, nanoclay, or a combination thereof.

8. The device of claim 1, wherein the active layer comprises a composite comprising micronized quantum dot complexes dispersed in the first matrix material, the micronized quantum dot complexes comprising the one or more populations of quantum dots dispersed in a base material, wherein the base material is micronized.

9. The device of claim 1, wherein the light source is a light emitting diode chip, a laser, a white light, a lamp, or any suitable combination thereof.

10. The device of claim 1, wherein the solid state lighting device is a light emitting diode.

11. The device of claim 1, wherein the solid state lighting device is a laser diode.

12. The device of claim 1, further comprising a reflector cup housing the light source.

13. A method of manufacturing a solid state lighting device comprising:

providing a light source;

dispersing quantum dots in a polymer or silicone having acrylate groups to form a first matrix material;

depositing the first matrix material either directly or indirectly on top of the light source; and

cross-linking the acrylate groups in the first matrix material to form a solid active layer.

14. The method of claim 13, wherein the quantum dots are dispersed in the polymer or silicone without a solvent.

15. The method of claim 13, wherein depositing a first matrix material either directly or indirectly on top of the light source comprises:

depositing an encapsulant layer on top the light source, the encapsulant layer comprising a second matrix material; and

depositing the first matrix material on top of the encapsulant layer.

16. The method of claim 13, wherein cross-linking the acrylate groups comprises exposing the first matrix material to ultraviolet irradiation.

17. The method of claim 16, wherein a curing dosage of the ultraviolet irradiation is 0.6 J/cm².

18. The method of claim 13, wherein cross-linking the acrylate groups comprises:

adding a thermal or an ultraviolet initiator to the first matrix material; and

applying heat or ultraviolet irradiation to the first matrix material to cross-link the acrylate groups.

19. The method of claim 18, wherein the thermal initiator is azobisisobutyronitrile.

20. The method of claim 18, wherein the ultraviolet initiator is 1 hydroxy cyclohexyl phenyl ketone.

21. The method of claim 13, wherein cross-linking the acrylate groups comprises:

adding a chemical additive to the first matrix material to cross-link the acrylate groups.

22. The method of claim 21, wherein the chemical additive is an amine, diamine, oleyl amine, docecyl amine, aminopropylmethoxysilane, bis(3-aminopropyl)-tetramethyl disiloxane, 3-aminopropyl dimethyl ethoxysilane, 3-aminopropylmethyl bis-(trimethyl siloxy) silane, or a combination thereof.

23. The method of claim 13, wherein the acrylate groups are cross-linked via an ultraviolet or thermal initiated vinylic addition, Michael addition or condensation.

24. The method of claim 13, further comprising:

adding 20% methyl hexahydrophthalic anhydride to the first matrix material.

25. The method of claim 13, further comprising:

adding an epoxy to the first matrix material.

26. A solid state lighting device comprising:

a light source; and

an active layer deposited either directly or indirectly on the light source, the active layer comprising;

a first matrix material;

a population of quantum dots dispersed in the first matrix material; and

non-absorbing light scattering dielectric particles dispersed in the first matrix material, wherein the particles have a diameter between 2 nanometers and 50 microns, have refractive indices greater than that of the first matrix material, and are substantially non-absorbent to light emitted by the light source or the population of quantum dots.

27. The device of claim 26, wherein the non-absorbing light scattering dielectric particles comprise titania or alumina particles.

28. The device of claim 26, wherein the concentration of the non-absorbing light scattering dielectric particles in the first matrix material is 0.1%-20%.

29. The device of claim 26, further comprising a transparent lens cap overcoating the active layer either directly or indirectly.

30. A solid state lighting device comprising:

a light source;

a first active layer deposited either directly or indirectly on top of the light source, the first active layer comprising a first population of quantum dots; and

a second active layer deposited either directly or indirectly on top of the first active layer, the second active layer comprising a second population of different quantum dots.

31. The solid state lighting device of claim 30, further comprising:

an encapsulant layer deposited on top of the light source, the encapsulant layer comprising a second matrix material, and

the first active layer deposited on top of the encapsulant layer.

32. The device of claim 30, further comprising another encapsulant layer deposited on top of the second active layer, the another encapsulant layer comprising a third matrix material.

33. The device of claim 30, wherein the first population of quantum dots is dispersed in a first matrix material and the second population of different quantum dots is not dispersed in a matrix material.

34. The device of claim 30, wherein a spacer film is disposed between the first and second active layers.