Bolometer Common Mode Rejection via Reference Current Injection
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Solution Overview
Problem
Bolometric detectors face challenges in achieving high thermal imaging resolution due to small relative variations in electrical resistance, which are further compromised by common mode current disturbances from thermal coupling with the substrate, making it difficult to accurately detect infinitesimal temperature variations in infrared radiation.
Innovation Solution
A resistive common mode rejection bolometer is used, with its resistance controlled by injecting a predefined reference current to isolate it from scene radiation, allowing the subtraction of common mode current from the imaging bolometer, thereby enhancing signal quality without the need for physical shields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a common mode rejection bolometer is used to subtract common mode current, then detection accuracy is improved, but physical shielding structures are required which increase device complexity
Solution Approach 1:
The patent replaces mechanical/physical shielding structures with an electrical control mechanism. A control circuit dynamically adjusts the resistance of the common mode rejection bolometer to match the resistance of the imaging bolometer, eliminating the need for complex physical shields while maintaining common mode rejection capability and detection accuracy.
Solution Approach 2:
The patent changes the resistance parameter of the common mode rejection bolometer dynamically through control circuitry. By adjusting the resistance to match the imaging bolometer's resistance, the system achieves effective common mode current subtraction without requiring physical isolation structures, thus simplifying the device while improving measurement precision.
2Object-affected harmful factors
If physical shields are used to isolate the common mode rejection bolometer, then isolation from radiation is improved, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent substitutes physical radiation shielding with an electrical control system that manages thermal coupling effects. The control circuit adjusts the bolometer resistance to compensate for thermal effects, achieving radiation isolation functionality through electrical means rather than complex manufacturing processes for physical shields.
Solution Approach 2:
The patent extracts the radiation isolation function from the physical structure and relocates it to the electrical control domain. Instead of building complex shields into the device structure, the system uses electronic control to achieve the same isolation effect, simplifying manufacturing while maintaining performance.
3Object-affected harmful factors
If the resistance of common mode rejection bolometer is controlled by injecting reference current, then isolation from scene radiation is achieved, but additional control circuitry is required
Solution Approach 1:
The patent replaces physical radiation isolation mechanisms with an electrical control system that uses reference current injection. The control circuit dynamically adjusts the bolometer resistance to match reference values, achieving radiation isolation through electrical control rather than mechanical/physical means.
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 effectively isolates the common mode rejection bolometer from infrared radiation, improving detection accuracy and reducing manufacturing costs by eliminating the need for complex shielding, while maintaining high sensitivity and resolution.
Implementation Method 1
a resistive common mode rejection bolometer associated electrically with the imaging bolometer so that the current flowing through the common mode rejection bolometer is subtracted from the current flowing through the imaging bolometer
Implementation Method 2
a resistive imaging bolometer sensitive to the radiation, intended to be connected electrically to a signal shaping circuit
Implementation Method 3
means for absorbing the infrared radiation and for converting it to heat
Implementation Method 4
means for controlling the resistance of the common mode rejection bolometer by injecting current therein
Data Source
AI summary
The invention relates to a device for detecting an electromagnetic radiation comprising a resistive imaging bolometer sensitive to the electromagnetic radiation to be detected, intended to be connected electrically to a signal shaping circuit, and a resistive common mode rejection bolometer that is associated electrically with the imaging bolometer, so that the current flowing through the common mode rejection bolometer is subtracted from the current flowing through the imaging bolometer, wherein it comprises means for controlling the resistance of the common mode rejection bolometer by injecting current therein.