Multi-Stage Thermal Isolator for Stiff Cryogenic FPA Mounting
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Solution Overview
Problem
Existing thermal isolators for focal plane arrays face challenges with low structural stiffness, high thermal conductivity, and high costs, particularly when supporting larger masses, which complicates the maintenance of cryogenic temperatures in devices like LWIR sensors.
Innovation Solution
A multi-stage thermal isolator design featuring a first and second interface platform with intermediate stages connected by struts, where the top surfaces are coplanar and a gap exists between the platforms to reduce heat transfer, allowing for efficient thermal isolation while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple components are assembled together to constrain six degrees of freedom of motion, then thermal isolation is improved, but structural stiffness decreases and resonant frequencies降低
Solution Approach 1:
The thermal isolator is divided into multiple discrete stages (first stage, second stage, third stage) connected by struts, where each stage provides thermal isolation while the distributed structure maintains structural integrity. The segmentation allows thermal gradients to be managed across stages while preserving overall stiffness through the rigid strut connections.
Solution Approach 2:
The multi-stage structure employs a nested arrangement where intermediate platforms are positioned within the footprint of outer platforms, creating a compact hierarchical structure. This nesting provides thermal isolation through the staged configuration while maintaining structural stiffness through the integrated strut system that connects all stages in a rigid framework.
2Ease of manufacture
If simpler thermal isolator designs are used for small masses, then ease of manufacture is improved, but thermal conductivity increases and isolation efficiency decreases
Solution Approach 1:
The isolator uses segmented stages connected by struts, where each stage can be manufactured separately and then assembled. This segmentation maintains manufacturing simplicity for individual components while achieving low thermal conductivity through the multi-stage configuration that interrupts heat flow paths.
Solution Approach 2:
The struts serve as intermediary elements connecting the stages, providing a simple yet effective means of structural support while maintaining thermal isolation. The struts are designed with minimal cross-sections to reduce thermal conductivity while preserving mechanical strength, thus simplifying the overall design without compromising isolation efficiency.
3Force
If thermal isolators are designed to support larger masses, then load capacity is improved, but structural stiffness decreases and thermal conductivity increases
Solution Approach 1:
The load is distributed across multiple stages and struts rather than concentrated in a single structure. Each strut is optimized for its specific load requirements, allowing the overall system to support larger masses while maintaining low thermal conductivity through the segmented configuration that prevents heat flow concentration.
Solution Approach 2:
The thermal isolator employs composite construction combining materials with different thermal and mechanical properties in the struts and platforms. This allows the structure to support larger masses with high structural stiffness while the composite material configuration minimizes thermal conductivity through strategic material selection and arrangement.
4Ease of manufacture
If conventional thermal isolators are used, then cost is reduced for simple designs, but coefficients of thermal expansion increase and precision decreases
Solution Approach 1:
The multi-stage design segments the thermal isolation function into discrete units that can be manufactured using standard processes at reasonable costs. Each stage is designed with controlled thermal expansion characteristics, and the modular nature allows for precision control of expansion coefficients in each segment while maintaining overall cost effectiveness.
Solution Approach 2:
Different regions of the thermal isolator are designed with locally optimized properties, including materials and geometries tailored to specific thermal expansion requirements. This local quality control allows precise management of thermal expansion coefficients in critical areas while using cost-effective materials and manufacturing methods in non-critical regions.
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 multi-stage thermal isolator provides improved thermal isolation and structural rigidity, reducing energy usage and maintaining precise temperature control for devices operating at cryogenic temperatures, such as LWIR focal plane arrays.
Implementation Method 1
a gap exists between the first interface platform and the second interface platform along an outer periphery of the second interface platform
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An apparatus includes a first interface platform (202) and a second interface platform (204). One interface platform is configured to be coupled to a support structure (102), and the other interface platform is configured to be coupled to a device (106) that operates at a temperature different than a temperature of the support structure. The apparatus also includes at least one intermediate stage platform (210) and struts (212, 214) connecting the first and second interface platforms to the at least one intermediate stage platform. Top surfaces of the interface platforms may be substantially coplanar. At least a portion of the second interface platform can reside within an opening of the first interface platform. The struts can be arranged in a nested configuration having first and second sets of struts, where the second set is located within the first set. Each strut in the first set could be substantially parallel to an adjacent strut in the second set.