Siloxane Encapsulant for LED Thermal Dissipation
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Solution Overview
Problem
Existing LED lamp technologies face challenges with thermal stability and heat dissipation, leading to performance degradation, and current polymer compositions are inadequate in addressing these issues.
Innovation Solution
A method for manufacturing LED lamps using a siloxane polymer encapsulant with silicon and oxygen in its backbone, aryl or alky groups, and functional cross-linking groups, along with particles and a catalyst, which is deposited and activated to enhance thermal conductivity and stability, while avoiding solvent use to prevent issues like shrinkage and mass loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer compositions are used in LED lamps, then the manufacturing process is simple, but thermal stability is inadequate leading to performance degradation
Solution Approach 1:
The patent employs a composite encapsulant material consisting of siloxane polymer base resin combined with inorganic particles (such as aluminum oxide, aluminum nitride, or boron nitride) dispersed throughout the matrix. This composite structure provides enhanced thermal conductivity and thermal stability while maintaining the manufacturing simplicity of polymer-based encapsulants. The inorganic particles form a thermal conduction network within the polymer matrix, enabling efficient heat dissipation from the LED junction.
Solution Approach 2:
The patent modifies the chemical composition and structural parameters of the encapsulant by selecting specific siloxane polymer types (dimethyl siloxane, phenyl methyl siloxane, etc.) and controlling the particle size distribution (0.1-10 micrometers) and concentration (30-70 weight percent) of inorganic fillers. These parameter optimizations enhance thermal stability and conductivity while managing viscosity and processability for practical manufacturing.
2Reliability
If particles are added to enhance thermal conductivity, then thermal stability improves, but viscosity increases making application difficult
Solution Approach 1:
The patent utilizes particles with non-uniform size distribution, combining fine particles (0.1-1 micrometer) that flow well and fill gaps with coarser particles (1-10 micrometers) that provide structural thermal conduction pathways. This local quality variation in particle sizing optimizes both thermal conductivity and rheological properties, preventing excessive viscosity increase while maintaining effective heat transfer.
Solution Approach 2:
The patent creates a porous or semi-porous structure within the encapsulant matrix through controlled particle packing and spacing. This porous architecture allows for better polymer matrix continuity, facilitating easier flow and application while maintaining thermal conduction through the particle network. The void spaces between particles are filled with the low-viscosity siloxane polymer, balancing structural integrity with processability.
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
The solution provides high thermal conductivity, excellent shelf life, minimal viscosity increase, and improved storage and application conditions, resulting in a thermally stable and efficient LED lamp with reduced solvent-related problems.
Implementation Method 1
an adhesive that bonds the die substrate to a support substrate... a siloxane polymer encapsulant with silicon and oxygen in its backbone, aryl or alky groups, and functional cross-linking groups, along with particles and a catalyst, which is deposited and activated
Implementation Method 2
The solution provides high thermal conductivity, excellent shelf life, minimal viscosity increase, and improved storage and application conditions, resulting in a thermally stable and efficient LED lamp
Data Source
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AI summary
An LED lamp is formed from a die substrate wherein the substrate has formed thereon a semiconductor material, an electrode for the application of a bias across the semiconductor material for causing light to be emitted therefrom, and an adhesive that bonds the die substrate to a support substrate, wherein the adhesive is a polymerized siloxane polymer having a thermal conductivity of greater than 0.1watts per meter kelvin(W/(m·K)) wherein the adhesive is not light absorbing, wherein the siloxane polymer has silicon and oxygen in the polymer backbone, as well as aryl or alky groups bound thereto, and wherein the adhesive further comprises particles having an average particle size of less than 100 microns.