Thermopile Self-Test via Opposite Polarity Current Injection
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Solution Overview
Problem
Conventional methods for testing and calibrating thermopile-based IR detectors require either exposure to IR radiation or an embedded heater, which reduces sensitivity, increases costs, and limits design optimization due to heat loss and additional components.
Innovation Solution
An electrical test method that applies currents of opposite polarities to the thermopile to measure voltage differences, canceling out resistance-related voltages and isolating the thermopile's sensitivity, allowing for self-testing and calibration without external IR exposure or heaters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an embedded heater is added to the thermopile for self-testing, then self-test capability is achieved, but sensitivity is reduced due to heat loss and additional components
Solution Approach 1:
The patent extracts the self-test function from a separate heater component and integrates it into the existing thermopile structure by utilizing one end of the thermopile as the heater element. This eliminates the need for additional heater components while maintaining self-test capability, thereby preserving detection sensitivity.
Solution Approach 2:
The thermopile structure is designed to serve multiple functions: it acts as both the detection element for IR radiation and the heating element for self-testing. By making the thermopile itself multi-functional, the patent avoids adding separate components that would compromise sensitivity.
2Extent of automation
If an embedded heater is added to the thermopile for self-testing, then self-calibration capability is achieved, but device complexity increases due to additional components
Solution Approach 1:
The patent removes the need for separate heater components by extracting the heating function and integrating it into the thermopile structure itself. This reduction in component count directly lowers device complexity while maintaining self-calibration capability.
Solution Approach 2:
The patent merges the heater function with the thermopile detection structure, combining two previously separate functions into a single integrated component. This merging eliminates additional parts and simplifies the overall device architecture.
3Extent of automation
If an embedded heater is added to the thermopile, then self-testing can be performed, but manufacturing cost increases
Solution Approach 1:
The patent extracts the heating function from separate heater components and integrates it into the thermopile structure, eliminating the need for additional parts that would increase manufacturing costs. This approach reduces material costs and assembly complexity.
Solution Approach 2:
By designing the thermopile to serve dual purposes (detection and heating), the patent eliminates the need for separate heater components, thereby reducing bill of materials costs and simplifying the manufacturing process.
4Measurement precision
If external IR radiation is used for testing, then accurate sensitivity measurement is achieved, but handling time increases due to movement to test socket
Solution Approach 1:
The patent enables the thermopile to perform self-testing by utilizing its own structure as the heater element. This self-service capability allows testing to be conducted in-situ without requiring external IR radiation sources or movement to specialized test sockets, thereby reducing handling time while maintaining measurement accuracy.
5Extent of automation
If a separate heater is used for self-testing, then thermal isolation of the thermopile is compromised, but self-test capability is achieved
Solution Approach 1:
The patent extracts the heating function from separate heater components that would compromise thermal isolation and instead integrates it directly into the thermopile structure. This integration ensures that the heating and detection functions share the same thermal path, maintaining thermal isolation while enabling self-testing.
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 method enhances sensitivity, reduces costs, and maintains design optimization by eliminating the need for additional components, enabling efficient self-testing and calibration of thermopile-based IR detectors.
Implementation Method 1
The Seebeck effect causes a slight voltage difference across each thermocouple - resulting in a much large increase in voltage difference across the thermopile which is the sum of the voltages across each thermocouple.
Implementation Method 2
Incident IR radiation causes a slight increase in temperature of the membrane.
Implementation Method 3
The heater is heated, and the signal on the thermopile is used to self-test or self-calibrate the device.
Data Source
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AI summary
We disclose herein a method for testing and/or calibrating a thermopile based device. The method comprising: applying an electrical bias of a first polarity to the thermopile based device and measuring a first value of an electrical parameter; and applying an electrical bias of a second polarity to the thermopile based device and measuring a second value of an electrical parameter.