Electromagnetic Radiation Detector with Shared Impedance Matching
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Solution Overview
Problem
Advanced electromagnetic radiation detection devices face challenges in maintaining a high signal-to-noise ratio and sensitivity due to reduced pixel sizes, which lead to increased noise levels and spatial noise gradients, especially when using microbolometers operating at room temperature.
Innovation Solution
The solution involves pooling impedance matching devices across multiple elementary detectors, allowing for larger transistors with greater gate surfaces, which reduces noise and enhances signal-to-noise ratio by maintaining identical resistance values for interconnections and minimizing parasitic resistances, thus improving sensitivity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pixel sizes are reduced to increase detector density, then the number of detectors per unit area increases, but noise levels increase and signal-to-noise ratio deteriorates
Solution Approach 1:
Multiple elementary detectors (22, 220) are grouped into subsets (300) that share a common impedance matching device (33). This merging approach allows the use of larger transistor gate surfaces for impedance matching, which reduces noise and improves signal-to-noise ratio while maintaining high detector density through reduced pixel sizes.
2Measurement precision
If impedance matching devices are made larger to reduce noise, then noise performance improves, but pixel area increases reducing detector density
Solution Approach 1:
The patent combines multiple elementary detectors into subsets that share common impedance matching devices. This allows the impedance matching transistors to have larger gate surfaces (improving noise performance) without proportionally increasing the area per detector, since the area cost is distributed across multiple detectors in each subset.
Solution Approach 2:
A single impedance matching device (33) serves multiple elementary detectors (22, 220) within a subset (300). This multi-functionality allows the impedance matching transistor to have a larger gate surface for better noise performance while the area overhead is amortized across multiple detectors, maintaining high detector density.
3Ease of manufacture
If interconnection resistances vary across the matrix, then manufacturing is simplified, but spatial noise gradients increase
Solution Approach 1:
The patent ensures that interconnections (301, 302) within each subset (300) have substantially equal resistance values, creating local uniformity. This local quality control reduces spatial noise gradients and improves measurement precision while allowing different subsets to have different interconnection characteristics, maintaining manufacturing flexibility.
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 results in improved signal-to-noise ratios and reduced spatial noise, enabling better sensitivity and uniformity across the detection matrix without introducing significant noise from the impedance matching devices, even with reduced pixel sizes and lower supply voltages.
Implementation Method 1
Each subset 300 of elementary detectors 22, 220 comprises a plurality of microbolometers 22, 220 having a resistance modifying themselves under the effect of incident electromagnetic radiation on their main surface
Implementation Method 2
an impedance matching device 33, preferably a transistor 33 mounted in common gate, called matching transistor 33
Data Source
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AI summary
Electromagnetic radiation detection device comprising multiple elementary detectors (32, 320) grouped into one or more subsets (300) each comprising several elementary detectors (32, 320), each elementary detector (32, 320) being connected by an interconnection (32.1, 320.1) to an impedance matching device (33), characterized in that: the impedance matching device (33) is common to all the elementary detectors (32, 320) of a single subset (300), in each subset (300) the interconnections (32.1, 320.1) have substantially the same resistance value.