Bolometric Detector Temperature Compensation Circuit

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Solution Overview

Problem

Bolometric detectors without thermal stabilization face challenges in maintaining signal stability due to substrate temperature variations, leading to reduced thermal resolution and increased electrical consumption, which limits their operational temperature range and performance.

Innovation Solution

A bolometric detector design incorporating a common mode bolometric compensation structure that adjusts voltage setpoints based on substrate temperature, allowing for effective compensation of substrate temperature variations and maintaining signal stability across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a Peltier module is used for substrate temperature stabilization, then temperature stability is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvesubstrate temperature stabilityVSAvoidcomponent complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention extracts and compensates for the temperature-dependent common-mode signal component separately from the detection signal. By measuring the substrate temperature and applying compensation to the bias voltage, the system eliminates the need for complex active temperature stabilization modules while maintaining signal stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the bias voltage parameter dynamically based on substrate temperature measurements. The control circuit adjusts the bias voltage to compensate for temperature variations, allowing the detector to maintain performance across a wide temperature range without requiring active thermal stabilization hardware.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If a Peltier module is used for substrate temperature stabilization, then temperature stability is improved, but power consumption increases

Engineering Contradiction:
Improvesubstrate temperature stabilityVSAvoidpower consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention extracts and compensates for the temperature-dependent common-mode signal component separately from the detection signal. By measuring the substrate temperature and applying compensation to the bias voltage, the system eliminates the need for power-consuming active temperature stabilization modules while maintaining signal stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detector system performs self-compensation for temperature variations by using its own substrate temperature measurements to adjust the bias voltage. This self-service approach eliminates the need for external active cooling or heating systems, significantly reducing power consumption.

Inventive Principle:
Principle #25Self-service

3Device complexity

If substrate temperature variations are not compensated, then device complexity is reduced, but signal stability deteriorates

Engineering Contradiction:
Improvecomponent simplicityVSAvoidsignal stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention implements a feedback mechanism where the substrate temperature is measured by a temperature sensor, and this measurement is fed back to the control circuit which adjusts the bias voltage accordingly. This closed-loop feedback system maintains signal stability without requiring complex active temperature stabilization hardware.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention changes the bias voltage parameter dynamically based on substrate temperature measurements. The control circuit adjusts the bias voltage to compensate for temperature variations, allowing the detector to maintain performance across a wide temperature range without requiring active thermal stabilization hardware.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If the operational temperature range is extended without thermal stabilization, then adaptability is improved, but thermal resolution deteriorates

Engineering Contradiction:
Improveoperational temperature rangeVSAvoidthermal resolution
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention changes the bias voltage parameter dynamically based on substrate temperature measurements. By adjusting the bias voltage in response to temperature variations, the system maintains optimal detection sensitivity and thermal resolution across an extended operational temperature range from -30°C to +90°C.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements a feedback mechanism where the substrate temperature is measured by a temperature sensor, and this measurement is fed back to the control circuit which adjusts the bias voltage accordingly. This closed-loop feedback system maintains signal stability without requiring complex active temperature stabilization hardware.

Inventive Principle:
Principle #23Feedback

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

The detector achieves improved thermal resolution and reduced electrical consumption, enabling operation from -30°C to +90°C while maintaining signal quality and extending the operational temperature range.

Implementation Method 1

a bolometric detector for the detection of infrared radiation... comprising an array of detection bolometers, each comprising a bolometric membrane suspended above a substrate... These membranes notably implement a function of absorption of incident infrared radiation, a function of conversion of the power of the absorbed radiation into heat power

Methodology Applied
Scientific EffectBolometric effect: Bolometer

Implementation Method 2

the electrical resistivity of the material, which varies significantly with temperature... a thermometric function of conversion of the heat power produced into a variation of the resistivity of the thermometric material

Methodology Applied
Scientific EffectTemperature-dependent electrical resistivity: Electrical Resistance

Implementation Method 3

bolometric detectors operating at room temperature have, from the outset of their industrial development, been equipped with a substrate temperature stabilization module, usually a Peltier module (TEC for the Anglo-Saxon expression Thermo Electric Cooler)

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 4

a biasing circuit to adjust the voltage across said detection bolometer according to a voltage setpoint... a biasing circuit to adjust the voltage across the compensation bolometer according to a voltage setpoint

Methodology Applied
Scientific EffectElectrical biasing: Electric Field

Data Source

PatentEP2770312B1Bolometric detector having a temperature dependent controlled polarisation
Publication Date: 2022.06.01 LYNRED
  • EP2770312B1 patent drawingFigure 1
  • EP2770312B1 patent drawingFigure 2
  • EP2770312B1 patent drawingFigure 3

AI summary

The detector (100) has a generation circuit (48) for generating voltage set points of detection and compensation branches according to size. A bolometer array (12) is exposed to a uniform reference scene, an average of differences between currents flowing through a set of detection bolometers and compensation bolometers or bolometers in continuous level is within an integrator dynamic range for a substrate temperature ranging between minus 30 degrees Celsius and 90 degrees Celsius.