Highly stable QDS-composites for solid state lighting and the method of making them through initiator-free polymerization

• US 9,506,627 B2
• Filed: 07/18/2013
• Issued: 11/29/2016
• Est. Priority Date: 08/06/2012
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.), Samsung Electronics Co. Ltd.
• Original Assignee: Koninklijke Philips N.V., QD Vision, Inc. (Samsung Electronics Co. Ltd.)
• Inventors: Xu, Shu, Ivan, Marius Gabriel, Breen, Craig Allen, Hikmet, Rifat Ata Mustafa
• Primary Examiner(s): Green, Tracie Y
• Application Number:
  US14/419,579
• Publication Number:
  US 20150204515A1
• Time in Patent Office: 1,230 Days
• US Class Current: 1/1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: F21K 9/62 using mixing chambers, e.g. housings with reflective walls
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F21Y 2115/30 Semiconductor lasers
• CPC Class Codes: G02F 1/01791 Quantum boxes or quantum dots
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: Y10S 977/774 Exhibiting three-dimensional carrier confinement, e.g. quantum dots
• CPC Class Codes: Y10S 977/779 Possessing nanosized particles, powders, flakes, or clusters other than simple atomic impurity doping
• CPC Class Codes: Y10S 977/89 : Deposition of materials, e.g. coating, cvd, or ald
• CPC Class Codes: Y10S 977/95 : Electromagnetic energy

Abstract

The invention provides a lighting device (1) comprising (i) a light source (10) configured to generate light source light (11), and (ii) a light converter (100) configured to convert at least part of the light source light (11) into visible converter light (121), wherein the light converter (100) comprises a polymeric host material (110) with light converter nanoparticles (120) embedded in the polymeric host material (110), wherein the polymeric host material (110) is based on radical polymerizable monomers, and wherein the polymeric host material (110) contains equal to or less then 5 ppm radical initiator based material relative to the total weight of the polymeric host material (110).

Claims

1. A lighting device comprising:

a light source configured to generate light source light (11),

a light converter configured to convert at least part of the light source light into visible converter light, wherein the light converter comprises a polymeric host material with light converter nanoparticles embedded in the polymeric host material, wherein the polymeric host material is based on radical polymerizable monomers, wherein the polymeric host material contains more than 0 ppm and equal to or less then 5 ppm radical initiator based material relative to the total weight of the polymeric host material, and wherein the light converter is enclosed by an encapsulation, wherein the encapsulation is configured to reduce exposure of the light converter to O₂.

2. The lighting device according to claim 1, wherein the polymeric host material is selected from the group consisting of a poly vinyl polymer, a poly acrylate polymer and a thiol-ene polymer.

3. The lighting device according to claim 1, wherein the light converter is enclosed by an O₂ and H₂O non-permeable encapsulation.

4. The lighting device according to claim 1, wherein the light converter nanoparticles are selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, and InAlPAs nanoparticles, and wherein the light converter comprises 0.001-25 wt. % light converter nanoparticles relative to the total weight of the light converter.

5. The lighting device according to claim 1, wherein the light converter nanoparticles are selected from the group consisting of CdS, CdSe, CdSe/CdS and CdSe/CdS/ZnS nanoparticles.

6. The lighting device according to claim 1, wherein the light converter nanoparticles comprise one or more of core-shell quantum dots and dots-in-rods nanoparticles.

7. The lighting device according to claim 1, wherein the encapsulation comprises a container, containing the light converter, and a cover, wherein the container and cover are attached to each other and enclose the light converter.

8. A liquid crystal display device comprising a back lighting unit, wherein the back lighting unit comprises one or more lighting devices claim 1.

9. A light converter unit comprising a light converter as defined in claim 1, and an encapsulation enclosing the light converter, wherein the encapsulation is configured to reduce exposure of the light converter to O₂.

10. A method for the production of a light converter, the light converter comprising a polymeric host material with light converter nanoparticles embedded in the polymeric host material, the method comprising:

providing a mixture comprising radical polymerizable monomers, light converter nanoparticles, and optionally radical initiator;

polymerizing the radical polymerizable monomers under low oxygen conditions, thereby providing the polymeric host material with light converter nanoparticles embedded in the polymeric host material;

wherein more than 0 ppm and equal to or less then 5 ppm radical initiator relative to the total weight of the polymeric host material is applied; and

enclosing the thus obtained light converter by an encapsulation.

11. The method according to claim 10, wherein polymerizing is started by irradiating the radical polymerizable monomers with radiation having a wavelength in the range of 300-460 nm.

12. The method according to claim 10, wherein the radical polymerizable monomers are selected from the group consisting of a vinyl monomer, an acrylate monomer, and a combination of a thiol and a diene, and wherein the mixture comprises 0.001-25 wt. % light converter nanoparticles relative to the total weight of the mixture.

13. The method according to claim 10, comprising polymerizing the radical polymerizeble monomers while maintaining the mixture in an inert gas atmosphere.

14. The method according to claim 10, wherein the method further comprises enclosing the thus obtained light converter by an oxygen non-permeable encapsulation.