Enhancement of output of optically pumped phosphor by use of surface nanostructures

Patent metadata

Field	Value
Publication number	US-10871644-B2
Application number	US-201916542912-A
Country	US
Kind code	B2
Filing date	Aug 16, 2019
Priority date	Feb 12, 2016
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

Abstract

Phosphor elements comprising phosphors in a host material having a phosphorescence-emitting surface with surface nanostructures are disclosed. Phosphor wheels having such phosphor elements, methods of making such phosphor elements, and methods of using such phosphor elements are also disclosed.

First claim

The invention claimed is:

1. A phosphor element comprising:
a host material defining the shape of the phosphor element; and
one or more phosphors dispersed in the host material that emit phosphorescence in response to an optical pump beam;
wherein the phosphor element has a phosphorescence-emitting surface with surface nanostructures which do not comprise the host material; and
wherein the surface nanostructures have a lateral dimension T x along an x-direction which is a statistical average spacing between adjacent surface nanostructures along the x-direction and a lateral dimension T y along a y-direction which is a statistical average spacing between adjacent surface nanostructures along the y-direction, wherein the x-direction and the y-direction are mutually orthogonal and the lateral dimensions T x and T y are different, and wherein the different lateral dimensions T x and T y are effective to lead to optical emission anisotropy in the phosphorescence.

2. The phosphor element of claim 1 , wherein the surface nanostructures comprise a membrane made of a different material from the host material and attached to the phosphorescence-emitting surface.

3. The phosphor element of claim 1 , wherein the surface nanostructures are laterally periodic in the x- and y-directions over the phosphorescence-emitting surface and the lateral dimensions T x and T y are the periodicity of the surface nanostructures in the x- and y-directions, respectively.

4. The phosphor element of claim 1 , wherein the surface nanostructures are non-periodically distributed in the x- and y-directions over the phosphorescence-emitting surface and the lateral dimensions T x and T y are the statistical average spacing between adjacent surface nanostructures in the x- and y-directions, respectively.

5. The phosphor element of claim 1 , wherein the surface nanostructures are frustoconical surface nanostructures.

6. The phosphor element of claim 1 , wherein the surface nanostructures are rounded bump surface nanostructures.

7. The phosphor element of claim 1 , wherein the surface nanostructures are tapered conical surface nanostructures.

8. The phosphor element of claim 1 , wherein no anti-reflection coating is disposed on the phosphorescence-emitting surface.

9. The phosphor element of claim 1 , wherein the host material is silicone or a transparent or translucent thermoplastic resin.

10. A phosphor wheel device comprising:
a wheel having a central axis via which the wheel is rotatable; and
a phosphor element as set forth in claim 1 disposed along a rim of the wheel and secured to the wheel.

11. A phosphor element comprising:
a host material defining the shape of the phosphor element; and
one or more phosphors dispersed in the host material that emit phosphorescence in response to an optical pump beam;
wherein the phosphor element has a phosphorescence-emitting surface with surface nanostructures having a lateral dimension T x along an x-direction which is a statistical average spacing between adjacent surface nanostructures along the x-direction and a lateral dimension T y along a y-direction which is a statistical average spacing between adjacent surface nanostructures along the y-direction,

wherein the x-direction and the y-direction are mutually orthogonal, the lateral dimensions T x and T y are different and the different lateral dimensions Tx and Ty are effective to lead to optical emission anisotropy in the phosphorescence.

12. The phosphor element of claim 11 , wherein the surface nanostructures are frustoconical surface nanostructures.

13. The phosphor element of claim 11 , wherein the surface nanostructures are rounded bump surface nanostructures.

14. The phosphor element of claim 11 , wherein the surface nanostructures are laterally periodic in the x- and y-directions over the phosphorescence-emitting surface and the lateral dimensions T x and T y are the periodicity of the surface nanostructures in the x- and y-directions, respectively.

15. The phosphor element of claim 11 , wherein the surface nanostructures are non-periodically distributed in the x- and y-directions over the phosphorescence-emitting surface and the lateral dimensions T x and T y are the statistical average spacing between adjacent surface nanostructures in the x- and y-directions, respectively.

16. A phosphor wheel device comprising:
a wheel having a central axis via which the wheel is rotatable; and
a phosphor element as set forth in claim 11 disposed along a rim of the wheel and secured to the wheel.

Assignees

• Materion Corp

Inventors

• Sprague Robert
• Newell Michael P

Classifications

• F21V7/30

  the coatings comprising photoluminescent substances · CPC title

• G02B1/118

  having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures · CPC title

• G03B33/08

  Sequential recording or projection (G03B33/02, G03B33/04, G03B33/06 take precedence) · CPC title

• F21V13/08

  the elements being filters or photoluminescent elements and reflectors · CPC title

• G02B26/008 Primary

  in the form of devices for effecting sequential colour changes, e.g. colour wheels · CPC title