Perforated Plastic Microbolometer for Thermal Isolation
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Solution Overview
Problem
Current microbolometers face challenges in achieving high thermal isolation and manufacturability, particularly in scaling to larger sizes due to the use of expensive MEMS silicon technology, which increases costs and complicates the integration of readout electronics.
Innovation Solution
A microbolometer design featuring a thermistor and electrodes on a plastic substrate with perforations to enhance thermal isolation, utilizing a gas flow through the perforations to localize heating and act as a heat sink, and employing conducting polymers or transparent conducting oxides for electrodes with low thermal conductivity to minimize heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MEMS silicon technology is used to make thermally isolated hanging membranes, then thermal isolation is improved, but manufacturing cost increases and scaling to larger sizes becomes complicated
Solution Approach 1:
The patent replaces expensive MEMS silicon technology with a plastic substrate that can be manufactured at lower cost and scaled more easily. The plastic substrate serves the same thermal isolation function but uses cheaper, more manufacturable materials and processes.
Solution Approach 2:
The patent changes the substrate material from silicon to plastic, fundamentally altering the manufacturing parameters and enabling lower-cost production and easier scaling to larger detector sizes while maintaining thermal isolation performance.
2Reliability
If gas flow is provided through perforations to isolate thermistors, then thermal isolation and response time are improved, but device complexity increases
Solution Approach 1:
The patent uses gas flow through perforations in the plastic substrate to achieve thermal isolation of thermistors. The gas flow acts as a thermal barrier and heat sink, improving thermal isolation and response time while adding minimal complexity compared to solid membrane structures.
3Reliability
If conventional electrodes are used, then electrical connection is achieved, but heat exchange between thermistors increases
Solution Approach 1:
The patent uses conducting polymers or transparent conducting oxides for electrodes instead of conventional metal electrodes. These materials provide the necessary electrical conductivity while having lower thermal conductivity, thereby reducing heat exchange between thermistors through the electrode connections.
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 improves thermal isolation, allows for faster response times, and reduces manufacturing costs by using a plastic substrate and gas flow to isolate thermistors from surrounding structures, enabling more efficient thermal radiation measurement.
Implementation Method 1
The thermistor is arranged to receive the thermal radiation for changing its temperature depending on a (flux of) the received thermal radiation
Implementation Method 2
Also, the gas flow may act as a heat sink such that the thermistor can more rapidly attain a steady state or equilibrium temperature indicative of the thermal radiation
Implementation Method 3
By providing perforations with gas flow adjacent and partially surrounding a circumference of the thermistor, its heating may be isolated from nearby circuitry
Implementation Method 4
The thermistor has a temperature dependent electric resistance
Data Source
AI summary
A microbolometer for measuring thermal radiation comprises an electrical circuit on a perforated plastic substrate. The electrical circuit comprises at least one thermistor having a temperature dependent electric resistance, wherein the thermistor is arranged to receive the thermal radiation for changing its temperature depending on a flux of the received thermal radiation. The electrical circuit is configured to measure the electric resistance of the thermistor for calculating the thermal radiation. The microbolometer is configured to cause a gas flow through the perforations for improving thermal characteristics.