Bolometer Remanence Reduction via Read Circuit Addressing
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Solution Overview
Problem
Bolometric detectors face issues with remanence phenomena, where excessive infrared exposure leads to persistent shifts in resistance, causing signal offset and saturation, and existing methods to mitigate this, such as using Peltier modules or modifying read circuit parameters, are either costly, time-consuming, or require additional equipment, leading to detector unavailability.
Innovation Solution
A method to control the resistance of bolometers by adjusting the addressing recurrence through the read circuit, specifically by modifying the frame frequency and selecting a window of bolometers to increase the frequency of current injection, without altering the operating point or requiring additional heating sources, thus reducing remanence effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Peltier modules are used to heat the focal plane to reduce remanence, then remanence reduction is achieved, but device complexity and cost increase
Solution Approach 1:
The bolometer's own read circuit current is used to heat the bolometer element, making the system self-serving. The regular addressing current that already flows through the bolometer during normal operation is sufficient to reduce remanence effects, eliminating the need for separate Peltier heating modules.
Solution Approach 2:
The read circuit serving function is made multi-functional by having it simultaneously perform remanence reduction. The same addressing current used for reading bolometer signals also serves to heat the bolometer and reduce remanence effects, combining multiple functions into a single circuit.
2Reliability
If traditional methods modify read circuit parameters to reduce remanence, then remanence is reduced, but detector unavailability time increases
Solution Approach 1:
The useful action of reducing remanence is made continuous by integrating it into the ongoing readout process. Instead of pausing detector operation for separate remanence reduction cycles, the addressing current continuously performs both reading and remanence reduction functions during normal operation.
3Reliability
If additional heating sources are used to reduce remanence, then remanence reduction is achieved, but energy consumption increases
Solution Approach 1:
The system uses its own operational current to reduce remanence, rather than requiring external energy sources. The addressing current that already flows through the bolometer during normal readout operations provides sufficient heating to reduce remanence effects without additional energy input.
4Speed
If high current is applied to reduce remanence rapidly, then remanence reduction speed is improved, but detector integrity is at risk
Solution Approach 1:
Instead of applying high current in a single intense pulse that could damage the detector, the system uses periodic addressing currents at the normal readout frequency. This periodic action gradually reduces remanence over multiple cycles, achieving effective correction without exceeding safe current thresholds that could compromise detector integrity.
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 approach allows for rapid correction of remanence in tens of milliseconds, reducing detector unavailability and energy consumption, while maintaining valid gain and offset correction tables, and achieving higher temperatures than traditional methods without risking detector integrity.
Implementation Method 1
a method for controlling the resistance of one or more bolometer(s) by adjusting the recurrence of addressing of the bolometer by the reading circuit
Data Source
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AI summary
The invention relates to a method for controlling the resistance of a bolometer in a bolometer matrix of a sensor, said sensor comprising a circuit for reading said matrix which is capable of addressing said bolometer. According to the invention, the method includes a step (46) of adjusting the recurrence of addressing the bolometer using the reading circuit.