Cryogenic camera assembly with non-cryogenic electrical connection subplatform
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Solution Overview
Problem
Infrared cameras with cooled detectors require a significant cooldown time due to increased thermal mass from new digital ROICs and capacitors, which lose capacitance at cryogenic temperatures, making it challenging to achieve operational temperatures efficiently.
Innovation Solution
A camera assembly design with a cryogenic platform and separate non-cryogenic subplatforms for electrical components, allowing electrical connections through openings or around the edges, reducing the thermal mass that needs to be cooled and maintaining capacitors at ambient temperature to minimize heat load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If new digital ROICs with thicker ceramic platforms and more on-board bypass capacitance are used, then the detector performance is improved, but the thermal mass increases and cooldown time is extended
Solution Approach 1:
The patent divides the camera assembly into two separate thermal zones: a cryogenic platform for the detector and ROIC, and a non-cryogenic subplatform for electrical components like capacitors. This segmentation allows the detector to achieve cryogenic temperatures faster by excluding non-cryogenic components from the cooled volume, thereby reducing cooldown time while maintaining detector performance.
Solution Approach 2:
The patent extracts electrical components (capacitors, resistors, etc.) from the cryogenic environment and places them on a non-cryogenic subplatform. This extraction removes unnecessary thermal mass from the cryogenic cooling system, reducing the time required to reach operational temperatures while preserving the detector's performance characteristics.
2Device complexity
If capacitors are placed on the cryogenic platform, then electrical connections are simplified, but capacitance is reduced by 66% at cryogenic temperatures
Solution Approach 1:
The patent segments the electrical system into cryogenic and non-cryogenic portions. Capacitors are placed on the non-cryogenic subplatform where they maintain full capacitance, while the cryogenic platform contains only the detector and ROIC. This segmentation resolves the contradiction by allowing capacitors to operate at optimal temperature while maintaining simplified electrical connectivity through the platform structure.
Solution Approach 2:
The non-cryogenic subplatform acts as an intermediary structure that provides electrical connections to the cryogenic platform without being cooled itself. This intermediary allows capacitors to remain at ambient temperature (maintaining capacitance) while still providing necessary electrical connections to the cryogenic detector system through conductive paths or feedthroughs.
3Loss of time
If all electrical components are cooled to cryogenic temperatures, then thermal mass is reduced, but component performance deteriorates and heat load increases
Solution Approach 1:
The patent applies segmentation by creating distinct thermal zones within the camera assembly. The cryogenic platform cools only the detector and ROIC to minimal thermal mass, while the non-cryogenic subplatform maintains electrical components at ambient temperature where they perform optimally. This segmented approach reduces overall cooldown time while preserving component performance.
Solution Approach 2:
The patent implements local quality by providing different thermal environments to different components based on their specific requirements. The detector requires cryogenic temperatures for optimal performance, while electrical components like capacitors require ambient temperatures. The non-cryogenic subplatform provides this localized thermal quality, allowing each component to operate in its optimal temperature range.
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
This design reduces cooldown time by 15% by isolating non-cryogenic components from the cryogenic interior, enabling faster operation of the camera assembly.
Implementation Method 1
the cold shield reflects stray radiation to keep the stray radiation from heating a cryogenic volume within the housing
Implementation Method 2
A finite amount of time is required to cool the cryogenic portion of the camera to operating temperatures
Data Source
AI summary
A camera assembly includes a housing inside of which components are maintained at a cryogenic temperature. The components maintained at cryogenic temperature include a detector that is mounted on an integrated circuit, which in turn is mounted on a platform, such as a ceramic platform, which includes electrical connections for the integrated circuit. The camera assembly also includes one or more subplatforms, maintained above the cryogenic temperature, such as ambient temperature, that receive electrical inputs from outside the housing, and make electrical connections to the platform. The connections may be made from the one or more subplatforms, through openings in the platform and/or outside one or more outer edges of the platform. The assembly may include covers of exposed parts of the one or more subplatforms, to facilitate thermal isolation between the interior of the assembly (at cryogenic temperature) and the one or more subplatforms (above cryogenic temperature).