Quantum dot films, lighting devices, and lighting methods

Patent metadata

Field	Value
Publication number	US-10444423-B2
Application number	US-201514612935-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Dec 30, 2008
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

Light-emitting quantum dot films, quantum dot lighting devices, and quantum dot-based backlight units are provided. Related compositions, components, and methods are also described. Improved quantum dot encapsulation and matrix materials are provided. Quantum dot films with protective barriers are described. High-efficiency, high brightness, and high-color purity quantum dot-based lighting devices are also included, as well as methods for improving efficiency and optical characteristics in quantum dot-based lighting devices.

First claim

What is claimed is:

1. A quantum dot (QD) phosphor film, comprising:
a QD phosphor material comprising at least one population of QDs embedded in at least one matrix material, wherein the QDs emit secondary light upon absorbance of primary light;
at least one bottom barrier film disposed on a first surface of the QD phosphor material;
at least one top barrier film disposed on a second surface of the QD phosphor material, wherein the second surface is opposite the first surface, and wherein the at least one top barrier film comprises a brightness enhancing film configured to reflect a portion of the primary light towards the QD phosphor material, such that the portion of the primary light has an increased optical path length within the QD phosphor material to cause increased primary light absorption by the QDs and thereby increase emission of secondary light; and
wherein the QD phosphor material is disposed between the at least one top barrier film and the at least one bottom barrier film.

2. The QD phosphor film of claim 1 , wherein the at least one bottom barrier film and/or the at least one top barrier film each comprises two barrier films, three barrier films, two or more barrier films, or three or more barrier films.

3. The QD phosphor film of claim 1 , wherein each barrier film comprises a transparent glass material, transparent polymer material, an oxide coating, or a combination thereof.

4. The QD phosphor film of claim 1 , wherein at least one said barrier film comprises a polymer film and an oxide coating on the polymer film.

5. The QD phosphor film of claim 4 , wherein the polymer comprises polyethylene terephthalate (PET) and the oxide layer comprises silicon oxide.

6. The QD phosphor film of claim 1 , further comprising one or more scattering features which scatter primary light in the QD phosphor film.

7. The QD phosphor film of claim 6 , wherein the scattering features increase the optical path length of primary light in the QD phosphor film.

8. The QD phosphor film of claim 6 , wherein the scattering features comprise scattering particles, scattering voids, scattering domains, or scattering surface features.

9. The QD phosphor film of claim 8 , wherein the scattering features comprise scattering particles, wherein the scattering particles comprise spherical scattering beads.

10. The QD phosphor film of claim 9 , wherein the scattering beads comprise silica, borosilicate, or polystyrene.

11. The QD phosphor film of claim 9 , wherein the scattering beads have a diameter between about 0.5 μm and about 2 μm, a diameter of about 0.5 μm, or a diameter of about 1 μm.

12. The QD phosphor film of claim 9 , wherein the scattering beads comprise silica, borosilicate, or polystyrene.

13. The QD phosphor film of claim 6 , wherein the scattering features are embedded in the at least one matrix material and have an index of refraction higher than that of any surrounding matrix material.

14. The QD phosphor film of claim 13 , wherein the scattering features have a refractive index of about 2 or greater, greater than 2, or about 2.

15. The QD phosphor film of claim 6 , wherein the scattering features have a dimension between about 0.5 μm and about 2 μm, about 0.5 μm, or a about 1 μm.

16. The QD phosphor film of claim 6 , wherein the QD phosphor material comprises a first matrix material having a first refractive index and at least a second matrix material having a second refractive index different than the first refractive index, wherein the scattering features comprise scattering domains comprising domains of the second matrix material dispersed within the first matrix material.

17. The QD phosphor film of claim 16 , wherein the first material comprises an epoxy and the second material has a refractive index of about 2 or greater, greater than 2, or about 2.

18. The QD phosphor film of claim 16 , wherein the first material comprises a transparent glass or polymer material and the second material comprises air.

19. The QD phosphor film of claim 16 , wherein the scattering features comprise a population of light emitting QDs which absorb primary light and emit blue light.

20. The QD phosphor film of claim 16 , wherein the scattering features comprise surface patterns formed on at least one surface of at least one of said barrier films.

21. The QD phosphor film of claim 20 , wherein the pattern comprises microtextures, prisms, pitches, pyramids, grooves, lenses, bumps, waves, scratches, or domes.

22. The QD phosphor film of claim 20 , wherein the scattering features have a size of about 5 μm or less, about 2 μm or less, about 1.5 μm or less, about 1 μm or less, or about 0.5 μm or less.

23. The QD phosphor film of claim 20 , wherein the scattering features are formed on at least one surface of at least one of said barrier films, which barrier film surface directly contacts the QD phosphor film.

24. The QD phosphor film of claim 16 , wherein the scattering features comprise scattering particles embedded in the at least one bottom barrier film.

25. The QD phosphor film of claim 16 , wherein the scattering features comprise scattering particles dispersed in the QD phosphor material, wherein the scattering particles have a density close to that of the QD phosphor material.

26. The QD phosphor film of claim 16 , wherein the scattering features comprise hollow beads.

27. The QD phosphor film of claim 16 , wherein the scattering features are dispersed uniformly in the QD phosphor material.

28. The QD phosphor film of claim 16 , wherein at least a portion of the scattering features are disposed in a same QD phosphor material layer as at least a portion of the QDs.

29. The QD phosphor film of claim 16 , wherein at least a portion of the scattering features are disposed between at least a first portion of the QDs and at least a second portion of the QDs.

30. The QD phosphor film of claim 16 , wherein at least a portion of the scattering features are disposed below at least a portion of the QDs, such that at least a portion of the scattering features are disposed between at least a portion of the QDs and the at least one bottom barrier film.

31. The QD phosphor film of claim 16 , wherein the scattering features are disposed below the QDs, wherein the scattering features are disposed between the QDs and the at least one bottom barrier film.

32. The QD phosphor film of claim 16 , wherein at least a portion of the scattering features are disposed above at least a portion of the QDs, such that at least a portion of the scattering features are disposed between at least a portion of the QDs and the at least one top barrier film.

33. The QD phosphor film of claim 16 , wherein the scattering features are disposed above the QDs, wherein the scattering features are disposed between the QDs and the at least one top barrier film.

34. The QD phosphor film of claim 16 , wherein the at least one bottom barrier film comprises two or more bottom barrier films, and the scattering features are disposed between the two or more bottom barrier films.

35. The QD phosphor film of claim 16 , wherein the top barrier film comprises two or more bottom barrier films, and the scattering features are disposed between the two or more bottom barrier films.

Assignees

• Nanosys Inc

Inventors

• Dubrow Robert S
• Freeman William P
• Lee Ernest
• Furuta Paul

Classifications

• G02B6/0073

  Light emitting diode [LED] · CPC title

• Y10S977/774

  Exhibiting three-dimensional carrier confinement, e.g. quantum dots · CPC title

• B32B2313/00

  Elements other than metals · CPC title

• B32B9/04

  comprising such {particular} substance as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00)} · CPC title

• G02B6/0053

  Prismatic sheet or layer; Brightness enhancement element, sheet or layer · CPC title