Thermally Conductive LED Encapsulant for Heat Management

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Solution Overview

Problem

High emission intensity white LEDs face thermal management issues due to phosphor and encapsulating materials acting as thermal insulators, limiting heat escape and maximum operating current.

Innovation Solution

A light emitting device with a thermally conducting encapsulating material, such as silver particles, distributed throughout the encapsulating medium to facilitate heat conduction away from the light emitting surface, while maintaining light transmission and ensuring uniform color distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If phosphor and encapsulating materials are used for wavelength conversion, then light emission intensity is improved, but thermal insulation increases causing heat accumulation

Engineering Contradiction:

Improvelight emission intensityVSAvoidheat accumulation

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The patent applies composite materials by combining phosphor particles with thermally conductive filler particles within the encapsulating material matrix. This creates a composite encapsulating material that simultaneously provides wavelength conversion (via phosphor) and thermal management (via conductive fillers), resolving the contradiction between maintaining light emission intensity and reducing heat accumulation.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If phosphor material is placed close to LED chip for efficient wavelength conversion, then light conversion efficiency is improved, but thermal degradation of phosphor increases

Engineering Contradiction:

Improvewavelength conversion efficiencyVSAvoidphosphor thermal stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces thermally conductive filler particles as an intermediary thermal management system between the LED chip and phosphor material. These fillers act as heat conduits that actively transport thermal energy away from the phosphor, allowing the phosphor to remain close to the chip for efficient conversion while preventing thermal degradation through active heat extraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The encapsulating material is formulated as a composite containing both phosphor particles for wavelength conversion and thermally conductive filler particles for heat management. This composite structure enables simultaneous optimization of conversion efficiency and thermal stability by integrating both functional components within the same material matrix.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If operating current is increased to achieve higher light intensity, then illumination output is improved, but thermal load on phosphor material increases causing degradation

Engineering Contradiction:

Improvelight output intensityVSAvoidthermal degradation

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful thermal energy that would otherwise degrade the phosphor into a manageable parameter by incorporating thermally conductive filler particles. These fillers capture the excess heat generated at high operating currents and channel it away from the phosphor, effectively transforming thermal harm into a controlled thermal management process that enables sustained high-intensity operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Improves thermal stability and reduces thermal degradation of the phosphor material, allowing for increased operating currents without bulkiness, enhancing the performance of high emission intensity white LEDs.

Implementation Method 1

the encapsulating material which incorporates a thermally conducting material. The thermally conducting material is preferably in the form of particles which are distributed throughout the volume of the encapsulating material and assists in the conduction of heat away from the light emitting surface(s) of the excitation source

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

at least one phosphor material configured to absorb at least a part of the excitation light and to emit light of a second wavelength range

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS8337029B2Light emitting device with phosphor wavelength conversion

Publication Date: 2012.12.25 INTEMATIX CORP

AI summary

A light emitting device comprises: an excitation source (LED) operable to generate excitation light of a first wavelength range and a phosphor (photo-luminescent) material configured to absorb at least a part of the excitation radiation and to emit light of a second wavelength range. Light emitted by the device comprises the combined light of the first and second wavelength ranges. The device is characterized by at least the light emitting surface of the excitation source being coated (encapsulated) with an encapsulating material which is transparent to light of the first and second wavelength ranges and which incorporates particles of a thermally conducting material (thermal conductivity ≧100 Wm−1K−1, e.g. silver, aluminum or carbon nano-particles) distributed throughout its volume. The phosphor material can be provided on a surface of the encapsulating material, incorporated in the encapsulating material and/or applied to the surface of, or incorporated, in an optical component such as a lens.