# US 8,541,933 B2 · Transparent thermally conductive polymer composites for light source thermal management

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- Number: US 8,541,933 B2
- Document ID: US8541933B2
- Status: Granted
- Kind: B2
- Application number: 12/979,611
- Filed: 2010-12-28
- Published: 2011-07-14
- Granted: 2013-09-24
- Earliest claimed: 2010-01-12
- Assignees: GE Lighting Solutions, LLC
- Applicants: Ashfaqul Islam Chowdhury; Gary Allen
- Inventors: Ashfaqul Islam Chowdhury; Gary Allen
- Web page: https://patentgrep.com/patent/US8541933B2

## CPC

- F21V 29/506: of globes, bowls or cover glasses
- F21K 9/232: specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
- F21V 29/77: with essentially identical diverging planar fins or blades, e.g. with fan-like or star-like cross-section
- F21V 3/02: characterised by the shape
- F21V 29/87: Organic material, e.g. filled polymer composites; Thermo-conductive additives or coatings therefor
- F21Y 2115/10: Light-emitting diodes [LED]
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

A light emitting apparatus is provided. The light emitting apparatus includes a light transmissive envelope, a light source being in thermal communication with a heat sink, and a plurality of heat fins in thermal communication with the heat sink and extending in a direction such that the heat fins are adjacent the light transmissive envelope. The plurality of heat fins comprises a carbon nanotube filled polymer composite.

## Claims

### Claim 1

A light emitting apparatus comprising:
a light transmissive envelope;
a light source being in thermal communication with a heat sink;
a plurality of heat fins in thermal communication with said heat sink and extending in a direction such that the heat fins are adjacent to said light transmissive envelope, wherein said plurality of heat fins comprises a carbon nanotube filled polymer composite; and
wherein said apparatus has a longitudinal axis dissecting said envelope and said heat sink, and wherein said heat sink has a light blocking angle of less than 30° as measured from said longitudinal axis at a point of exit from said heat sink.

### Claim 2 (depends on 1)

The light emitting apparatus of claim 1, wherein the thermal conductivity of the apparatus is between about 10-1000 W/m-K.

### Claim 3 (depends on 1)

The light emitting apparatus of claim 1, wherein the thermal conductivity of the apparatus is about 20-300 W/m-k.

### Claim 4 (depends on 1)

The light emitting apparatus of claim 1, wherein said heat fins have at least about 90% optical transmittance.

### Claim 5 (depends on 1)

The light emitting apparatus of claim 1, wherein the carbon nanotube loading is between about 2-10 wt %.

### Claim 6 (depends on 1)

The light emitting apparatus of claim 1, wherein said carbon nanotubes are single-walled carbon nanotubes (SWNT).

### Claim 7 (depends on 6)

The light emitting apparatus of claim 6, wherein said carbon nanotube filled polymer composite comprises a cloth weaved with long strands of single-walled carbon nanotubes.

### Claim 8 (depends on 7)

The light emitting apparatus of claim 7, wherein said nanotubes filled polymer composite comprises multiple layers of single walled carbon nanotube weaved cloth.

### Claim 9 (depends on 8)

The light emitting apparatus of claim 8, wherein said single walled carbon nanotubes are embedded in the multiple layers within a transparent polymer matrix such that each single walled nanotube strand is positioned on top of the same strand of nanotube as a cloth position below.

### Claim 10 (depends on 1)

The light emitting apparatus of claim 1, wherein said at least one light source comprises at least one of an LED and OLED.

### Claim 11 (depends on 1)

The light emitting apparatus of claim 1 wherein said heat fins communicate optically with light emitted from said light transmissive envelope.