Pyroelectric Resonator Infrared Sensor Design
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Solution Overview
Problem
Current uncooled infrared detectors face challenges with slow response time and reduced detection sensitivity due to device scaling, while cooled photonic detectors require cryogenic cooling, adding size, weight, and cost to the sensing platform.
Innovation Solution
An infrared sensor using a resonant sensor element with a mechanical resonator and IR absorber, where the resonator exhibits pyroelectric and piezoelectric effects, and the quality factor is enhanced using an acoustoelectric effect to accurately measure incident infrared radiation by altering resonant characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal detectors are used for uncooled operation, then cooling requirements are eliminated, but response time becomes slow and detection sensitivity decreases with device scaling
Solution Approach 1:
The patent employs a mechanical resonator that vibrates at a specific resonant frequency to detect infrared radiation. The resonator's mechanical vibration amplifies the detection signal, enabling high sensitivity in uncooled operation. When infrared radiation heats the resonator, it causes a frequency shift that is detected with high precision, resolving the contradiction between uncooled operation and detection sensitivity.
Solution Approach 2:
The patent changes the operating parameters by using a resonator's natural frequency as the detection parameter instead of simple temperature change measurement. By monitoring the frequency shift of the resonator in response to thermal energy from infrared radiation, the system achieves high detection sensitivity without requiring cooling, thus resolving the contradiction between uncooled operation and sensitivity.
2Measurement precision
If photonic detectors are used for high sensitivity and fast response, then detection performance improves, but cryogenic cooling is required adding size, weight, and cost
Solution Approach 1:
The patent replaces the complex cryogenic cooling system with a simple mechanical resonator-based detection mechanism. Instead of using cooled photonic detectors, the invention uses an uncooled mechanical resonator whose frequency shifts in response to infrared radiation, achieving comparable or superior sensitivity without the need for mechanical refrigeration systems, thereby eliminating size, weight, and cost penalties.
Solution Approach 2:
The mechanical resonator is inherently sensitive to thermal energy and automatically responds to infrared radiation through frequency shifts. The resonator serves its own detection function without requiring external cooling systems or complex electronic stabilization, enabling the detector to be lightweight and simple while maintaining high detection sensitivity.
3Speed
If device size is reduced to improve response time, then speed increases, but detection sensitivity is impaired
Solution Approach 1:
The patent uses a small mechanical resonator that can be fabricated at micro-scale dimensions, enabling fast response times. The resonator's high natural frequency and quality factor amplify the detection signal, compensating for the small size. This allows the device to maintain both small dimensions for fast response and high sensitivity through the resonant amplification effect.
Solution Approach 2:
The patent employs a dynamic detection mechanism where the resonator's oscillation state changes in response to infrared radiation. By monitoring the dynamic frequency shift rather than static properties, the system achieves high sensitivity even with small, fast-responding devices. The dynamic nature of the measurement allows small devices to maintain detection capability through their resonant behavior.
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 enables high-sensitivity, lightweight, and low-power infrared detection without the need for cooling, providing accurate thermal imaging with improved response time and reduced environmental interference.
Implementation Method 1
an IR absorber arranged to receive and absorb incident infrared radiation
Implementation Method 2
The resonator includes a temperature-responsive material that exhibits pyroelectric and piezoelectric effects
Implementation Method 3
The resonator includes a temperature-responsive material that exhibits pyroelectric and piezoelectric effects
Implementation Method 4
increasing the quality factor of the resonator using an acoustoelectric effect by applying an electric field across the resonator
Data Source
AI summary
An infrared sensor formed from a resonant sensor element having a mechanical resonator and an IR absorber arranged to receive and absorb incident infrared radiation. The resonator includes a temperature-responsive material that exhibits pyroelectric and piezoelectric effects. The IR absorber is thermally coupled to the resonator such that the resonator receives thermal energy from at least some of the incident infrared radiation absorbed by the IR absorber. The resonator has at least one resonant characteristic that varies based on the amount of thermal energy received from the IR absorber by the resonator. A sensor array and infrared sensing method are included that use a plurality of the infrared sensors along with a reference sensor having the same construction as the other sensor elements, except that the sensor either lacks the IR absorber or has it arranged so that it is not exposed to the incident infrared radiation.