Infrared Detector Resonant Unit Broadband Absorption
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Solution Overview
Problem
Infrared detectors with bolometers using the Salisbury screen structure face challenges in reducing pixel size while maintaining high resolution and temperature accuracy, leading to decreased incident energy and signal-to-noise ratio due to the narrow bandwidth of plasmonic absorbers, which limits their ability to absorb broadband infrared light effectively.
Innovation Solution
The design incorporates a resonant unit with multiple sub-resonators spaced apart, including a thermistor layer and a connection unit with a thermal leg and reflective layer, to induce resonance across multiple wavelengths, enhancing absorption efficiency and signal detection by spacing the thermistor layer from the substrate and minimizing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to achieve high resolution, then the resolution is improved, but the incident energy on each pixel decreases
Solution Approach 1:
The patent changes the resonant frequency parameters of multiple resonators to match different wavelength bands (first wavelength band and second wavelength band), enabling the absorber to resonate and absorb infrared energy across a broadband spectrum. This allows smaller pixels to capture sufficient energy across multiple wavelengths.
Solution Approach 2:
The patent uses a composite structure combining multiple resonators with different resonant frequencies, a Salisbury screen structure, and a plasmonic absorber. This composite design enables broadband absorption by combining the advantages of different absorption mechanisms across multiple wavelength bands.
2Device complexity
If a Salisbury screen structure is used with reduced screen size, then the device complexity is reduced, but the signal-to-noise ratio decreases
Solution Approach 1:
The patent merges the Salisbury screen structure with multiple resonators and a plasmonic absorber into a unified broadband absorption structure. This combination maintains the simplicity of the Salisbury screen while adding resonant enhancement across multiple wavelength bands to improve signal-to-noise ratio.
Solution Approach 2:
The patent employs resonators that mechanically vibrate at specific resonant frequencies when exposed to infrared radiation at corresponding wavelengths. This mechanical vibration (resonance) enhances the absorption of incident energy, improving the signal-to-noise ratio without increasing structural complexity.
3Reliability
If a plasmonic absorber is used to achieve broadband absorption, then the absorption ratio is improved, but the bandwidth remains narrow
Solution Approach 1:
The patent segments the absorption function into multiple resonators, each responsible for a specific wavelength band. The first resonator handles the first wavelength band while the second resonator handles the second wavelength band, collectively achieving broadband absorption through division of labor.
Solution Approach 2:
The patent introduces dynamic resonance by using resonators with different resonant frequencies that can respond to different wavelength bands. This dynamic response allows the absorber to adapt to a broader spectrum of infrared radiation, expanding the effective bandwidth beyond what a single-frequency plasmonic absorber can achieve.
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 achieves high absorption ratios for broadband wavelengths, improving the signal-to-noise ratio and enabling high-resolution thermal imaging by effectively absorbing infrared light across a wide spectral range, overcoming the limitations of narrow bandwidth plasmonic absorbers.
Implementation Method 1
a resonant unit spaced apart from the substrate to generate heat by inducing resonance at a plurality of resonant wavelengths and absorb infrared light
Implementation Method 2
a plurality of thermistor layers respectively supporting the resonant units and having resistance values varying with temperature changes in the resonant units
Implementation Method 3
The infrared detector may further include a reflective layer disposed between the substrate and the thermistor layer to reflect incident infrared light
Data Source
Figure 1~2
Figure 3~4
Figure 5~6A
AI summary
An infrared detector may include a substrate (110), a resonant unit (120)spaced apart from the substrate 110), the resonant unit configured to generate heat by inducing resonance at a plurality of wavelengths of incident infrared light, a thermistor layer (130) configured to support the resonant unit and be spaced apart from the resonant unit (120), the thermistor layer having a resistance value that varies according to the heat generated in the resonant unit, and a connection unit (150) configured to support the thermistor layer (130) such that the thermistor layer is spaced apart from the substrate and electrically connect the thermistor layer to the substrate.