Infrared Thermal Detector Using LSPR Absorption
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Solution Overview
Problem
Infrared thermal detectors face challenges in achieving high sensitivity and sub-miniaturization due to increased thermal noise and reduced incident energy as pixel size decreases, limiting the size of pixels to larger than the diffraction limit of the wavelength used.
Innovation Solution
The implementation of a structure that utilizes localized surface Plasmon resonance (LSPR) to absorb infrared light, reducing thermal mass and conductance by condensing light onto a small area, allowing for a smaller pixel size while maintaining sensitivity through a patterned metal and thermistor material layer configuration, and incorporating a thermal leg with semi-rings and connectors to enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is decreased to achieve high resolution, then the number of pixels increases, but the amount of incident energy decreases and temperature noise increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform thermal conductance distribution through the meander-shaped thermal leg structure. The thermal leg has varying cross-sectional areas along its length, with narrower sections providing higher thermal resistance and wider sections providing lower thermal resistance. This localized variation in thermal conductance optimizes the balance between thermal isolation (to maintain temperature sensitivity) and heat dissipation (to prevent overheating), enabling high sensitivity in miniaturized pixels without requiring uniform thermal properties throughout the structure.
Solution Approach 2:
The patent implements the nesting principle by integrating the meander-shaped thermal leg structure within the confined space of each pixel. The thermal leg is folded back on itself multiple times in a compact meander pattern, allowing a long thermal conduction path to be contained within a small pixel area. This nested configuration enables effective thermal management in miniaturized detectors by fitting complex thermal pathways into limited spatial dimensions, thereby maintaining temperature precision while reducing pixel size.
2Measurement precision
If pixel size is decreased to achieve high resolution, then the number of pixels increases, but thermal noise increases due to increased thermal conductance
Solution Approach 1:
The patent applies local quality by creating a non-uniform thermal conductance distribution through the meander-shaped thermal leg structure. The thermal leg has varying cross-sectional areas along its length, with narrower sections providing higher thermal resistance and wider sections providing lower thermal resistance. This localized variation in thermal conductance optimizes the balance between thermal isolation (to maintain temperature sensitivity) and heat dissipation (to prevent overheating), enabling high sensitivity in miniaturized pixels without requiring uniform thermal properties throughout the structure.
Solution Approach 2:
The patent implements dynamics by designing the thermal leg with a meander shape that enables dynamic thermal response. The varying cross-sectional areas create different thermal time constants along the thermal leg, allowing the structure to adaptively manage heat flow under different operating conditions. This dynamic thermal characterization enables the detector to optimize its thermal response time and noise performance based on the incident energy levels and environmental conditions.
3Speed
If thermal mass is reduced to improve response time, then the detector becomes more responsive, but sensitivity decreases due to reduced temperature change
Solution Approach 1:
The patent applies local quality by creating a non-uniform thermal conductance distribution through the meander-shaped thermal leg structure. The thermal leg has varying cross-sectional areas along its length, with narrower sections providing higher thermal resistance and wider sections providing lower thermal resistance. This localized variation in thermal conductance optimizes the balance between thermal isolation (to maintain temperature sensitivity) and heat dissipation (to prevent overheating), enabling high sensitivity in miniaturized pixels without requiring uniform thermal properties throughout the structure.
Solution Approach 2:
The patent implements dynamics by designing the thermal leg with a meander shape that enables dynamic thermal response. The varying cross-sectional areas create different thermal time constants along the thermal leg, allowing the structure to adaptively manage heat flow under different operating conditions. This dynamic thermal characterization enables the detector to optimize its thermal response time and noise performance based on the incident energy levels and environmental conditions.
4Measurement precision
If thermal conductance is reduced to improve temperature sensitivity, then temperature precision increases, but heat dissipation capability decreases
Solution Approach 1:
The patent applies local quality by creating a non-uniform thermal conductance distribution through the meander-shaped thermal leg structure. The thermal leg has varying cross-sectional areas along its length, with narrower sections providing higher thermal resistance and wider sections providing lower thermal resistance. This localized variation in thermal conductance optimizes the balance between thermal isolation (to maintain temperature sensitivity) and heat dissipation (to prevent overheating), enabling high sensitivity in miniaturized pixels without requiring uniform thermal properties throughout the structure.
Solution Approach 2:
The patent implements dynamics by designing the thermal leg with a meander shape that enables dynamic thermal response. The varying cross-sectional areas create different thermal time constants along the thermal leg, allowing the structure to adaptively manage heat flow under different operating conditions. This dynamic thermal characterization enables the detector to optimize its thermal response time and noise performance based on the incident energy levels and environmental conditions.
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 infrared thermal detectors to achieve triple the temperature change of existing detectors in the same size, allowing for sub-miniaturization and high sensitivity with reduced thermal conductance and mass, thus overcoming the limitations of pixel size and noise.
Implementation Method 1
a structure that utilizes localized surface Plasmon resonance (LSPR) to absorb infrared light
Implementation Method 2
a resistance change, a polarity change, an electromotive force change, and/or a flexural change may be generated according to characteristics of a material
Data Source
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AI summary
According to example embodiments, an infrared thermal detector includes a substrate, a detector spaced apart from the substrate, and a thermal leg configured to transmit a signal from the detector to the substrate. The detector is configured to absorb incident infrared light via localized surface Plasmon resonance, and the detector is configured to change a resistance value according to a temperature change caused by the absorbed infrared light.