Light emitting device with phase changing off state white material and methods of manufacture

Patent metadata

Field	Value
Publication number	US-10276763-B2
Application number	US-201715722903-A
Country	US
Kind code	B2
Filing date	Oct 2, 2017
Priority date	Oct 4, 2016
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Light emitting devices (LEDs) are described herein. An LED includes a light emitting semiconductor structure, a wavelength converting material and an off state white material. The light emitting semiconductor structure includes a light-emitting active layer disposed between an n-layer and a p-layer. The wavelength converting material has a first surface adjacent the light emitting semiconductor structure and a second surface opposite the first surface. The off state white material is in direct contact with the second surface of the wavelength converting material and includes multiple core-shell particles disposed in an optically functional material. Each of the core-shell particles includes a core material encased in a polymer or inorganic shell. The core material includes a phase change material.

First claim

What is claimed is:

1. A light emitting device (LED) comprising:
a light emitting semiconductor structure comprising a light-emitting active layer disposed between an n-layer and a p-layer;
a wavelength converting material having a first surface adjacent the light emitting semiconductor structure and a second surface opposite the first surface; and
an off state white material in direct contact with the second surface of the wavelength converting material, the off state white material comprising a plurality of core-shell particles disposed in an optically functional material, each of the core shell particles comprising a core material that includes a phase change material encased in a polymer or inorganic shell.

2. The LED of claim 1 , wherein the phase change material is selected from the group consisting of a paraffin and a deuterated paraffin analog.

3. The LED of claim 1 , wherein the off state white material comprises between 5 percent and 40 percent by volume fraction of the core-shell p articles.

4. The LED of claim 1 , wherein the core material further comprises silicone in a ratio of 50% to 90% silicone to the phase change material by weight.

5. The LED of claim 1 , wherein the polymer or inorganic shell is one of melamine formaldehyde based or silica based.

6. The LED of claim 1 , wherein the shell is a polymer shell and is deuterated.

7. The LED of claim 1 , wherein the phase change material has a melting point of between 43° C. and 100° C.

8. The LED of claim 1 , wherein the phase change material is one of deuterated tricosane, deuterated docosane, deuterated hexacosane, and deuterated octacosane.

9. The LED of claim 1 , wherein the light emitting semiconductor structure is a blue light emitting semiconductor structure.

10. The LED of claim 9 , wherein the wavelength converting material comprises one of a yellow-emitting phosphor material or green-emitting and red-emitting phosphor materials.

11. The LED of claim 1 , wherein each of the plurality of particles has a diameter of between 1 μm and 50 μm.

12. The LED of claim 1 , wherein the optically functional material comprises silicone and the plurality of core-shell particles are dispersed in the silicone.

13. The LED of claim 1 , wherein the optically functional material comprises a temperature and light resistant matrix and the plurality of core-shell particles are embedded in the temperature and light resistant matrix.

14. The LED of claim 1 , wherein the off state white material is disposed on the wavelength converting material as a layer or a film.

15. The LED of claim 1 , wherein the optically functional material forms a lens.

Assignees

• Lumileds Llc

Inventors

• Estrada Daniel
• Shimizu Ken
• Roitman Daniel
• Bohmer Marcel Rene
• Kang Edward

Classifications

• C09K5/06 Primary

  the change of state being from liquid to solid or vice versa · CPC title

• C09C1/0081

  Composite particulate pigments or fillers, i.e. containing at least two solid phases, except those consisting of coated particles of one compound (C09C1/0015, C09C1/0078 take precedence) · CPC title

• C01P2006/60

  Optical properties, e.g. expressed in CIELAB-values · CPC title

• C09C1/0084

  containing titanium dioxide · CPC title

• H01L33/505

  Electricity · mapped topic