Infrared Sensor Floating Support and Current Amplifier for Low-SNR Detection
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Solution Overview
Problem
Infrared sensors face challenges in maintaining high signal-to-noise ratio (S/N) due to reduced pixel size, leading to weak infrared light power and difficulty in achieving spatial temperature differences, which are exacerbated by the use of semiconductor switches with imperfect insulation, causing leakage of infrared detection signals and inaccurate measurement of offset components and 1/f noise.
Innovation Solution
The infrared sensor employs a floating supporter with a phononic crystal structure to maintain a temperature difference and uses a current-input amplifier with semiconductor switches configured to short-circuit the thermoelectric converter, reducing signal leakage and enabling accurate measurement of offset components and 1/f noise by switching between noise measurement and infrared measurement modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the area of light receiver is reduced to miniaturize pixels, then high-resolution infrared imaging is achieved, but the power of received infrared light becomes very weak and spatial temperature difference cannot be obtained
Solution Approach 1:
The support structure is segmented into phononic crystal regions with periodic patterns that create thermal insulation barriers, separating heat flow paths to maintain temperature difference while supporting the miniaturized light receiver
Solution Approach 2:
The floating supporter is designed with localized phononic crystal structures having different thermal conductivities in different regions, providing high heat insulation where needed while maintaining mechanical support functionality, enabling the light receiver to maintain spatial temperature difference despite miniaturization
2Productivity
If semiconductor switches are used to select pixels, then pixel scanning is achieved, but leakage of infrared detection signals occurs due to imperfect insulation
Solution Approach 1:
Before measuring offset components or 1/f noise, the system performs a calibration operation where pixel selection switches are turned off to establish baseline values, then subtracts these calibration values from subsequent measurements to eliminate leakage effects
Solution Approach 2:
The system uses calibration measurements taken with switches off to provide feedback for correcting subsequent noise measurements, dynamically compensating for switch leakage effects and enabling accurate offset and 1/f noise measurement despite imperfect switch insulation
3Measurement precision
If pixel selection switches are turned off to measure offset components and 1/f noise, then noise measurement is achieved, but infrared detection signals leak due to imperfect switch insulation
Solution Approach 1:
The system performs a preliminary calibration operation by turning off pixel selection switches and measuring baseline values, then uses these calibration values to correct subsequent noise measurements, eliminating the effect of signal leakage
Solution Approach 2:
Calibration measurements provide feedback that enables the system to compensate for switch leakage effects in real-time, allowing accurate noise measurement by subtracting the calibrated leakage baseline from the measured signal
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 configuration enhances infrared detection accuracy by minimizing signal leakage, allowing for high-accuracy and high-speed detection operations by effectively canceling noise components, thereby improving the S/N ratio.
Implementation Method 1
a phononic crystal structure is provided in the floating supporter
Implementation Method 2
high heat insulating properties of the phononic crystal structure
Implementation Method 3
an infrared sensor element using a thermocouple, a thermopile, or the like that uses the Seebeck effect, that is, an electromotive voltage based on a temperature difference as an infrared detection signal
Implementation Method 4
the hot junction temperature on the light receiver whose temperature has been changed by radiation of infrared light
Data Source
AI summary
An infrared sensor includes a substrate, an infrared sensor element that generates an infrared detection signal, a parallel switch connected to the infrared sensor element, and an amplifier that amplifies the infrared detection signal generated by the infrared sensor element. The infrared sensor element includes a light receiver, a floating supporter that supports the light receiver in a floating manner so that a gap is formed between the substrate and the light receiver, and a thermoelectric converter that generates the infrared detection signal based on heat generated by the light receiver. The thermoelectric converter includes a first terminal that outputs the infrared detection signal, and a second terminal that is maintained at a predetermined potential. The parallel switch connects the first terminal and the second terminal so that the parallel switch is capable of short-circuiting the first terminal and the second terminal. The amplifier is a current-input amplifier.