Microbolometer Bias Circuit Heating Compensation
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Solution Overview
Problem
Conventional microbolometer focal plane arrays face performance limitations due to temperature changes during infrared radiation detection, which restrict the output signal range and overall performance.
Innovation Solution
The implementation of a microbolometer circuit with a bias circuit and an output circuit that provide a varying signal level to compensate for changes in microbolometer resistance caused by temperature increases, effectively addressing pulsed bias heating through anti-ramp techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bias current is provided to the microbolometer to generate an output signal, then the detection function is enabled, but the bias current increases the temperature of the microbolometer causing resistance changes that limit the output signal range
Solution Approach 1:
The patent applies preliminary anti-action by introducing a compensation signal that anticipates and counteracts the temperature-induced resistance changes before they fully impact the output signal. The compensation signal is generated based on expected temperature drift from bias current, and is applied in advance to offset the harmful effects, thereby maintaining the microbolometer's resistance stability and extending the output signal range.
Solution Approach 2:
The patent implements feedback by continuously monitoring the microbolometer's resistance changes and using this information to adjust the compensation signal. The system measures the actual temperature drift effects on resistance and feeds this information back to the compensation mechanism, which then dynamically adjusts the compensation signal to maintain optimal performance and extend the output signal range.
2Measurement precision
If the microbolometer operates with bias current for infrared detection, then detection performance is achieved, but temperature changes restrict the available output signal range
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the compensation signal parameters (amplitude, frequency, or waveform) based on the microbolometer's operating conditions and temperature drift characteristics. By changing these signal parameters adaptively, the system maintains measurement precision across varying temperature conditions while maximizing the available output signal range and improving overall adaptability.
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 compensation method enhances the output signal range and improves the performance of microbolometer focal plane arrays by mitigating the effects of pulsed bias heating, resulting in a more stable and accurate infrared detection process.
Implementation Method 1
the bias current increasing a temperature of the first microbolometer
Implementation Method 2
A microbolometer, which detects infrared radiation, is well known in the art
Data Source
AI summary
A microbolometer circuit includes, in accordance with an embodiment, a first microbolometer and a bias circuit, coupled to the first microbolometer, configured to provide a bias current to the first microbolometer to provide a first output signal based on a resistance of the first microbolometer. An output circuit, coupled to the bias circuit and the first microbolometer, is configured to provide an output signal based on the first output signal, wherein the bias circuit or the output circuit or both are configured to provide a varying signal level to compensate the first output signal for a change in the resistance of the first microbolometer due to the bias current increasing a temperature of the first microbolometer.