Semiconductor Light Emitter Cooling With Internal Convection
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Solution Overview
Problem
The low thermal conductivity of the layers in Distributed Bragg Reflectors (DBRs) in Vertical Cavity Surface Emitting Lasers (VCSELs) leads to heat trapping within the resonator, preventing the achievement of designed light emission characteristics.
Innovation Solution
A semiconductor light emitting device with a heat control member using a cooling fluid to disperse heat, featuring regions with varying wettability, surface tension, and surface roughness to enhance convection and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a DBR with multilayer structure is used to resonate light, then light emission characteristics are improved, but heat is trapped inside the resonator due to low thermal conductivity of each layer
Solution Approach 1:
The patent extracts the heat dissipation function from the DBR structure by introducing a separate heat control member positioned between the light emitting unit and the DBR. This heat control member includes a cooling fluid that actively removes heat from the resonator, separating the optical resonance function (performed by DBR) from the thermal management function (performed by heat control member), thereby resolving the contradiction between maintaining light emission characteristics and preventing heat trapping.
2Temperature
If cooling fluid is introduced to disperse heat, then heat dissipation is improved, but convection efficiency is reduced without proper surface properties
Solution Approach 1:
The patent applies local quality by creating regions with different wettability properties on the heat control member surface. Specifically, it introduces a first region with higher wettability than the front surface of the light emitting unit, and optionally a second region with higher water repellency or oil repellency than the first region. This spatial variation in surface properties enhances convection efficiency of the cooling fluid by promoting better fluid-surface interaction in critical areas, thereby improving overall heat dissipation productivity.
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 device efficiently cools the light emitting unit, maintaining original light emission characteristics, improving output and reliability, and reducing failure rates by effectively managing heat dissipation.
Implementation Method 1
a heat control member that disperses heat of the light emitting unit using a cooling fluid inside of the sealing member. The heat control member may cause the heat of the light emitting unit using the cooling fluid to convect between the light emitting unit and the sealing member.
Implementation Method 2
The cooling fluid may be a gas, a liquid, or a solid that takes in the heat, and evaporates, melts, or sublimes.
Data Source
AI summary
Deterioration of light emission characteristics due to heat is prevented. A semiconductor light emitting device includes: a light emitting unit; a sealing member that includes a transmission part that allows light emitted from the light emitting unit to transmit; and a heat control member that disperses heat of the light emitting unit using a cooling fluid inside of the sealing member.