Reflective Die Attach Material for LED Substrate Thermal Management
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Solution Overview
Problem
Highly reflective substrates used in LED devices are prone to degradation due to heat-generated migration and oxidation, leading to reliability issues and reduced lifespan, especially under demanding conditions.
Innovation Solution
A reflective die attach material is applied beyond the periphery of the LED die to cover areas susceptible to heat-induced degradation, using thermal modeling to determine the extent of coverage and prevent substrate tarnishing and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If highly reflective substrates are used in LED devices, then efficiency is improved, but long-term reliability deteriorates due to heat-induced migration and oxidation
Solution Approach 1:
The substrate surface is segmented into two distinct regions: a highly reflective region for light reflection and efficiency, and a non-reflective die attach region for heat dissipation and reliability. This segmentation allows each region to perform its specialized function without compromising the other.
Solution Approach 2:
Different regions of the substrate are given different optical properties. The first region has high reflectivity for light management, while the second region has low reflectivity to facilitate heat dissipation. This local differentiation resolves the contradiction by optimizing each area for its specific purpose.
2Use of energy by moving object
If reflective material is used to improve light reflection, then light extraction efficiency is improved, but substrate degradation accelerates at higher temperatures
Solution Approach 1:
The substrate is divided into a reflective region and a non-reflective die attach region. The reflective region maintains high light extraction efficiency, while the non-reflective region serves as a thermal management zone that reduces temperature-induced degradation, thereby extending substrate lifespan.
Solution Approach 2:
The die attach material in the non-reflective region acts as an intermediary that facilitates heat dissipation from the LED die to the substrate, protecting the reflective regions from excessive heat and preventing accelerated degradation.
3Manufacturing precision
If die attach material is confined to the LED periphery, then manufacturing precision is maintained, but areas susceptible to heat-induced degradation are not protected
Solution Approach 1:
The die attach material is applied with varying optical properties across different locations. The region directly under the LED die and extending beyond its periphery is made non-reflective to maximize heat dissipation, while other areas maintain reflectivity. This localized approach protects vulnerable areas without compromising manufacturing precision.
Solution Approach 2:
The solution extends the die attach material coverage beyond the two-dimensional periphery of the LED die into the radial direction on the substrate surface. This dimensional extension ensures that areas susceptible to heat-induced degradation are covered and protected while maintaining precise alignment.
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 effectively extends the operational life of LED devices by reducing substrate degradation and maintaining reliability through controlled heat dissipation and light reflection, with the die attach material covering areas where temperature increases significantly.
Implementation Method 1
a reflective region disposed at a top surface of the substrate. The reflective region comprises at least one reflective layer
Implementation Method 2
The die attach comprises reflective material and extends beyond the periphery of the light emitting diode to cover an area of the top surface of the substrate that is outside the periphery of the light emitting diode
Data Source
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AI summary
Devices and methods including an LED and reflective die attach material are described herein. The devices can include a reflective substrate (e.g., a substrate that includes a silver layer) to which one or more LED die are attached using the die attach material. The die attach material extends beyond the periphery of the LED die to cover an area of the substrate surface.