Light-scattering color-conversion material layer

• US 20070201056A1
• Filed: 02/24/2006
• Published: 08/30/2007
• Est. Priority Date: 02/24/2006
• Status: Abandoned Application

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, Ronald, Burberry, Mitchell
• Application Number:
  US11/361,094
• Publication Number:
  US 20070201056A1
• Time in Patent Office: Days
• US Class Current: 358/1.900
• CPC Class Codes: B41M 5/265 for the production of optical filters or electrical components
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: H10K 2102/331 Nanoparticles used in non-emissive layers, e.g. in packaging layer
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/877 comprising scattering means

Abstract

A light-scattering color-conversion material layer having two sides, comprising first light-scattering particles intermixed with second different color-conversion material particles, wherein the concentration of the light scattering particles is greater towards a first side of the layer relative to the concentration of light-scattering particles towards the opposite side of the layer, and/or wherein the concentration of the color-conversion material particles is less towards the first side of the layer relative to the concentration of color-conversion material particles towards the opposite side of the layer. A method of making such a light-scattering color-conversion material layer is also described, and light emitting devices comprising one or more EL elements formed on a substrate and such a light-scattering color-conversion material layer optically coupled with the EL element.

Claims

1. A light-scattering color-conversion material layer having two sides, comprising first light-scattering particles intermixed with second different color-conversion material particles, wherein the concentration of the light scattering particles is greater towards a first side of the layer relative to the concentration of light-scattering particles towards the opposite side of the layer, or wherein the concentration of the color-conversion material particles is less towards the first side of the layer relative to the concentration of color-conversion material particles towards the opposite side of the layer.

2. A light-scattering color-conversion material layer of claim 1, wherein the concentration of the light scattering particles is greater towards a first side of the layer relative to the concentration of light-scattering particles towards the opposite side of the layer, and the concentration of the color-conversion material particles is less towards the first side of the layer relative to the concentration of color-conversion material particles towards the opposite side of the layer.

3. A light-scattering color-conversion material layer of claim 1, wherein first light-scattering particles are located within 500 nm of the first side of the layer over more than half of the area of the first side.

4. A light-scattering color-conversion material layer of claim 1, wherein the light-scattering particles have a first average size and the color-conversion particles have a second average size smaller than the first average size.

5. The light-scattering color-conversion material layer of claim 1, wherein the light-scattering particles have an average maximum dimension size greater than 400 nm.

6. The light-scattering color-conversion material layer of claim 1, wherein the light-scattering particles have an average maximum dimension size less than two microns.

7. The light-scattering color-conversion material layer of claim 1, wherein the color-conversion material particles have an average maximum dimension size less than 400 nm.

8. The light-scattering color-conversion material layer of claim 1 further comprising an adhesive binder and/or surfactant.

9. The light-scattering color-conversion material layer of claim 1 further comprising a matrix in which either or both of the light-scattering particles and/or color-change material particles are dispersed.

10. The light-scattering color-conversion material layer of claim 9 wherein the matrix is a polymer, resin, or urethane, or a curable material.

11. The light-scattering color-conversion material layer of claim 1 wherein the layer is self-supporting.

12. The light-scattering color-conversion material layer of claim 1 wherein the layer is coated on a support.

13. A method of forming a light-scattering color-conversion material layer comprising the steps of:

coating a first layer comprising light-scattering particles on a substrate; and

coating a second layer comprising color-conversion material particles over the first layer, wherein the color-conversion material particles and light-scattering particles intermix at the interface of the first and second layers to form an integral layer, wherein the concentration of the light scattering particles is greater towards a first side of the integral layer relative to the concentration of light-scattering particle towards the opposite side of the integral layer, or wherein the concentration of the color-conversion material particles is less towards the first side of the integral layer relative to the concentration of color-conversion material particle towards the opposite side of the integral layer.

14. The method of claim 13, further comprising the step of mixing the light-scattering particles and/or color-change material particles in a matrix material and the mixture is coated on the substrate.

15. The method of claim 13, further comprising the steps of mixing the light-scattering particles in a solvent and mixing the color-change material particles in a matrix material, and wherein the solvent mixture is coated as the first layer, and the matrix mixture is coated as the second layer.

16. The method of claim 13, further comprising the steps of mixing the light-scattering particles in a first solvent and mixing the color-change material particles in a second solvent, and wherein the first solvent mixture is coated as the first layer, and the second solvent mixture is coated as the second layer.

17. A light emitting device, comprising:

one or more EL elements formed on a substrate; and

a light-scattering color-conversion material layer optically coupled with the EL element,

wherein light emitted from the EL element at a first frequency is absorbed and re-emitted by the color-conversion material at a second, lower frequency and light emitted from, and entrapped in, the EL element is extracted by the light-scattering particles, wherein the concentration of the light scattering particles is greater towards a first side of the layer adjacent to the EL element relative to the concentration of light-scattering particle towards the opposite side of the layer, and wherein the concentration of the color-conversion material particles is less towards the first side of the layer relative to the concentration of color-conversion material particle towards the opposite side of the layer.

18. The light emitting device of claim 17, wherein the EL element comprises an OLED element.

19. The light emitting device of claim 17, further comprising a cover through which light is emitted, and a low-index layer formed between the cover and the light-scattering color-conversion material layer.

20. The light emitting device of claim 17, wherein light is emitted through the substrate and further comprising a low-index layer formed between the substrate and the light-scattering color-conversion material layer.