Light output device having an array of cavities with different refractive index within the encapsulation layer

Patent metadata

Field	Value
Publication number	US-9293650-B2
Application number	US-201214128803-A
Country	US
Kind code	B2
Filing date	Jun 28, 2012
Priority date	Jul 1, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A light output device and manufacturing method in which an array of LEDs ( 34 ) is embedded in an encapsulation layer ( 32 ). An array of cavities ( 30 ) (or regions of different refractive index) is formed in the encapsulation layer ( 32 ). The cavities/regions ( 30 ) have a density or size that is dependent on their proximity to the light emitting diode ( 34 ) locations, in order to reduce hot spots (local high light intensity areas) and thereby render the light output more uniform over the area of the device.

First claim

The invention claimed is:

1. A light output device comprising:
an array of light sources;
an encapsulation layer within which the light source array is embedded;
an array of cavities or regions of different refractive index to the refractive index of the encapsulation layer, formed in the encapsulation layer;
wherein the cavities or regions have a size that is dependent on their proximity to the light source locations, the cavities being more densely packed and having a smaller diameter near the light source locations causing stronger light backscattering close to the light source locations; and
wherein the encapsulation layer comprises a polymer matrix with an additive with a lower boiling point than a boiling point of the matrix.

2. A device as claimed in claim 1 , herein the additive is adapted to be evaporated by the heat of the light sources.

3. A device as claimed in claim 1 , wherein the additive is adapted to be evaporated by the light of the light sources.

4. A device as claimed in claim 1 , wherein the encapsulation layer comprises a phase-separated polymer-dispersed liquid.

5. A device as claimed in claim 1 , wherein the regions comprise a polymer.

6. A light output device comprising:
an array of light sources;
an encapsulation layer within which the light source array is embedded;
an array of cavities of different refractive index to the refractive index of the encapsulation layer, formed in the encapsulation layer,
wherein the cavities have a number density and size that is dependent on their proximity to the light source locations;
the encapsulation layer including a polymer matrix with an additive having a boiling point lower than a boiling point of the matrix;
the cavities being more densely packed and having a smaller diameter near the light source locations causing stronger light backscattering close to the light source locations.

Assignees

• Cornelissen Hugo Johan
• Cennini Giovanni
• Gommans Hendrikus Hubertus Petrus
• Krijn Marcellinus Petrus Carolus Michael
• Van Delden Martinus Hermanus Wilhelmus Maria
• Stofmeel Leon Wilhelmus Godefridus
• Yu Jianghong
• Koninkl Philips Nv

Inventors

• Cornelissen Hugo Johan
• Cennini Giovanni
• Gommans Hendrikus Hubertus Petrus
• Krijn Marcellinus Petrus Carolus Michael
• Van Delden Martinus Hermanus Wilhelmus Maria
• Stofmeel Leon Wilhelmus Godefridus
• Yu Jianghong

Classifications

• H10W90/00

  Package configurations · CPC title

• G09F2013/222

  with LEDs · CPC title

• G09F13/22 Primary

  electroluminescent (electroluminescent light sources per se H05B33/00) · CPC title

• H10H20/0363

  of optical field-shaping means · CPC title

• H10H20/0362

  of encapsulations · CPC title