Laser Package Mounting to Reduce Thermal Interface Pumping
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Solution Overview
Problem
High-power laser systems face challenges in efficient cooling and heat removal due to imperfections in the thermal interface between the laser package and the housing, leading to reduced heat-transfer efficacy and potential heat-induced failures from thermal cycling and coefficient of thermal expansion mismatches.
Innovation Solution
A laser device with a thermally conductive package attached to a cooling plate, incorporating an electrically insulating barrier and multiple layers of thermal-interface material, including a spring-fastener mechanism to maintain mechanical connection and reduce thermal pumping, and a divided electrically insulating barrier to minimize thermally induced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conformal thermal-interface material is used to improve thermal contact, then thermal conduction is enhanced, but the material is prone to thermal pumping and mechanical wear under thermal cycling
Solution Approach 1:
The thermal-interface material is segmented into a modular structure comprising a compliant substrate layer and a thermally conductive top layer. This segmentation allows each layer to perform its specialized function: the substrate provides mechanical compliance and stress distribution, while the top layer provides thermal conduction, thereby reducing thermal pumping effects
Solution Approach 2:
The invention uses a composite thermal-interface material structure combining a compliant polymer substrate with a thermally conductive filler-containing top layer. This composite structure leverages the advantages of both materials: the polymer provides compliance and stress resistance, while the filler-rich top layer provides high thermal conduction, solving the contradiction between thermal performance and pumping resistance
2Object-affected harmful factors
If an electrically insulating barrier is used to prevent electrical conduction, then electrical isolation is achieved, but thermally induced stress increases due to CTE mismatch
Solution Approach 1:
The electrically insulating barrier is designed with locally varying properties: it has different thermal expansion coefficients in different regions to match adjacent components, and varying thickness to distribute thermal stresses. This local quality adjustment reduces overall thermally induced stress while maintaining electrical isolation
Solution Approach 2:
The invention changes the physical parameters of the electrically insulating barrier, specifically its thermal expansion coefficient and thickness profile, to optimize the balance between electrical isolation and stress reduction. By adjusting these parameters, the barrier can accommodate thermal cycling without generating excessive stress
3Stability of the object's composition
If rigid attachment is used to maintain mechanical connection, then structural stability is improved, but thermal pumping of the interface material is exacerbated
Solution Approach 1:
The attachment mechanism transitions from rigid to dynamic/compliant, allowing the interface material and components to move slightly in response to thermal expansion and contraction. This dynamic compliance reduces the mechanical pumping action that occurs with rigid attachments while maintaining stable mechanical connection through elastic recovery
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 reduces thermal pumping and maintains thermal management efficacy, preventing heat-induced failures by allowing for thermally induced expansion and contraction while preventing electrical conduction and enhancing heat dissipation.
Implementation Method 1
allowing motion of the laser package in response to thermal cycles resulting from operation of the beam emitter
Implementation Method 2
a thermally conductive cooling plate for conducting heat away from the laser package
Implementation Method 3
an electrically isolating barrier layer for preventing electrical conduction between the laser package and the cooling plate
Data Source
AI summary
In various embodiments, laser devices feature means, such as fasteners, for attaching a laser package to a cooling plate, which allow motion of the laser package in response to thermal cycles resulting from operation of a beam emitter therewithin. Embodiments of the invention additionally or instead include laser devices featuring segmented barrier layers for electrically isolating the laser package from the cooling plate.