Infiltration Matrix Conversion Element for Low-Porosity Heat Dissipation
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Solution Overview
Problem
Existing LED conversion elements face challenges in achieving high thermal conductivity, high color rendering index (CRI), and thin form factors, particularly for applications requiring high luminance and high current densities, due to limitations in thermal conductivity materials and manufacturing processes.
Innovation Solution
A conversion element with a matrix comprising 10 to 50 vol% phosphor and an infiltration matrix, which infiltrates into the pores of the matrix to reduce porosity and enhance thermal conductivity, using materials like water glass and sol-gel materials with low volume shrinkage, allowing for maximally thin and highly filled designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If inorganic conversion elements with high filler content of phosphor embedded in water glass or condensed monoaluminum phosphate are used, then thermal conductivity is improved, but interconnected microchannels and porosity are formed during drying and thermal condensation, reducing thermal conductivity and increasing scattering
Solution Approach 1:
The patent applies preliminary action by pre-filling the pore spaces with additional phosphor material before the final sintering process. This ensures that when the matrix material shrinks during drying and thermal condensation, the pore spaces are already occupied, preventing the formation of interconnected microchannels and reducing final porosity while maintaining high thermal conductivity
Solution Approach 2:
The patent changes parameters by controlling the volume shrinkage characteristics of the matrix material during drying and thermal condensation. By selecting materials and processing conditions that minimize excessive shrinkage, the formation of interconnected pores is reduced, thereby maintaining low porosity and high thermal conductivity in the final conversion element
2Ease of manufacture
If silicone is used as the matrix for the phosphor, then manufacturing is simplified, but thermal conductivity is low and thermal stability is limited, restricting LED applications to current densities below 2 A/mm²
Solution Approach 1:
The patent uses composite materials by combining phosphor particles with an inorganic matrix material such as water glass or condensed monoaluminum phosphate. This composite structure provides both the manufacturing simplicity of a slurry-based process and the high thermal conductivity required for high current density applications, overcoming the limitations of pure silicone matrices
3Quantity of substance
If conversion elements are made thicker to accommodate phosphor loading, then phosphor content increases, but heat dissipation capability decreases, limiting possible applications
Solution Approach 1:
The patent changes parameters by optimizing the particle size distribution and packing density of the phosphor and matrix materials. This allows achieving high phosphor content (high volume filling) in thin conversion elements, maintaining excellent heat dissipation capability while maximizing light conversion efficiency. The controlled volume shrinkage during processing ensures dense packing without creating pores that would hinder heat transfer
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 achieves low porosity, improved thermal conductivity, and enhanced light out-coupling, enabling efficient heat dissipation and high CRI while reducing adhesive thickness and scattering, suitable for high-power LED applications.
Implementation Method 1
at least one matrix comprising at least one infiltration matrix
Implementation Method 2
combining a chip as a light source and a conversion element using e.g. phosphors to convert at least part of the radiation of the light source
Data Source
AI summary
The invention relates to a conversion element comprising a wavelength-converting conversion material, a matrix material in which the conversion material is inserted, and a substrate on which the matrix material and the conversion material are directly arranged, the matrix material comprising at least one condensed sol-gel material selected from the following group: water glass, metal phosphate, aluminium phosphate, monoaluminium phosphate, modified monoaluminium phosphate, alkoxytetramethoxysilane, tetraethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, titanium alkoxide, silica sol, metal alkoxide, metal oxane or metal alkoxane, the conversion element being arranged in the beam path of a laser source, the conversion element being mounted in a mechanically immobile manner in relation to the laser source, and the radiation of the laser source being dynamically arranged in relation to the conversion element.