Dual-Resistor Temperature Sensor for Infrared Detector Compensation
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Solution Overview
Problem
Infrared imaging applications face challenges in accurately measuring the temperature of infrared detectors or sensors, as existing technologies lack effective methods to compensate for temperature-related artifacts, leading to inaccuracies in temperature estimation and changes over time.
Innovation Solution
A temperature sensor system comprising first and second resistors with different thermal conductivities and temperature coefficients of resistance, integrated with a measurement circuit to estimate substrate temperature by measuring changes in resistance, allowing for sensitive detection of die temperature in infrared detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single resistor is used for temperature measurement, then the device complexity is low, but the measurement precision is insufficient due to inability to differentiate substrate and die temperatures
Solution Approach 1:
The temperature sensor is segmented into two distinct resistive elements: a first resistor coupled to the substrate and a second resistor coupled to the die. Each resistor measures temperature at its specific location, enabling differentiation between substrate temperature and die temperature. This segmentation resolves the contradiction by providing precise multi-point temperature measurement while maintaining a relatively simple integrated circuit structure.
Solution Approach 2:
Each resistor is designed with specific local characteristics: the first resistor has a first temperature coefficient and the second resistor has a second temperature coefficient. By assigning different temperature coefficients to different locations (substrate vs. die), the sensor achieves precise local temperature measurement capability, improving measurement precision without excessive complexity.
2Reliability
If temperature compensation is not applied, then the device complexity is low, but the reliability of infrared imaging is reduced due to temperature-related artifacts
Solution Approach 1:
The measurement circuit uses the resistance values from both resistors as feedback signals to determine substrate and die temperatures. These temperature measurements are then used to apply compensation to the infrared imaging process, correcting temperature-related artifacts. This feedback mechanism improves reliability by enabling real-time temperature compensation while using a straightforward circuit implementation.
Solution Approach 2:
The temperature sensor system provides self-service by using the same integrated circuit structure to both measure temperature and perform compensation. The resistors and measurement circuit work together autonomously to monitor and correct temperature effects, improving reliability without requiring external complex compensation systems.
3Measurement precision
If resistors with identical thermal conductivities are used, then the manufacturing precision is high, but the measurement precision is reduced due to inability to detect temperature differences
Solution Approach 1:
The patent deliberately introduces asymmetry by using resistors with different thermal conductivities: a first thermal conductivity for the substrate path and a second thermal conductivity for the die path. This asymmetric design enables the measurement circuit to detect and differentiate temperature differences between substrate and die, improving measurement precision. The intentional mismatch in thermal conductivities is manufactured within acceptable tolerances, balancing measurement capability with manufacturing feasibility.
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 solution enables accurate temperature measurement and compensation for thermal artifacts in infrared detectors, enhancing the precision of infrared imaging by differentiating between substrate and die temperatures, thus improving temperature estimation and change detection.
Implementation Method 1
a first resistor having a first temperature coefficient of resistance and associated with a first thermal path having a first thermal conductivity between the first resistor and a substrate; a second resistor having a second temperature coefficient of resistance and associated with a second thermal path having a second thermal conductivity between the second resistor and the substrate
Implementation Method 2
a measurement circuit responsive to changes in the resistance of the first and second resistors to estimate changes in temperature
Implementation Method 3
a first thermal path having a first thermal conductivity between the first resistor and a substrate and a second thermal path having a second thermal conductivity between the second resistor and the substrate
Data Source
AI summary
A temperature sensor for use in an infrared detector the temperature sensor comprising: a first resistor associated with a first thermal path having a first thermal conductivity between the first resistor and a substrate and a first temperature coefficient of resistance; a second resistor associated with a second thermal path having a second thermal conductivity between the second resistor and the substrate and a second temperature coefficient of resistance, and a measurement circuit responsive to changes in the resistance of the first and second resistors to estimate changes in temperature, and wherein at least one of (a) the first and second thermal conductivities are different or (b) the first and second temperature coefficients of resistance are different.