Infrared Sensor Reference Pixel Noise Suppression
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Solution Overview
Problem
Infrared solid-state image sensors face issues with noise during signal readout, particularly longitudinal streak noise, due to the influence of threshold voltage dispersion and noise components on the signal line.
Innovation Solution
The solution involves an infrared solid-state image sensor design with a matrix of sensitive and reference pixels, where reference pixels are used to provide a stable reference potential by averaging outputs from multiple insensitive pixels, reducing noise and improving signal-to-noise ratio through differential amplification of signal potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold voltage clamp processing is used to compensate for threshold dispersion, then amplifying transistor performance is improved, but longitudinal streak noise appears due to noise component holding
Solution Approach 1:
The patent extracts and removes the harmful noise component from the signal line by introducing reference pixels that generate only noise without signal. By reading out reference pixel outputs and subtracting them from detection pixel outputs, the noise component is separated and eliminated, solving the longitudinal streak noise problem while maintaining threshold voltage compensation benefits
Solution Approach 2:
The patent introduces reference pixels as an intermediary element that generates a noise-only signal. This intermediary signal serves as a reference that can be subtracted from the detection pixel signals, allowing the harmful noise to be identified and removed without affecting the useful infrared detection function
2Reliability
If multiple reference pixels are used to provide stable reference potential, then noise suppression is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple reference pixels into a unified reference potential system where all reference pixels share common connection nodes. This merging approach allows the system to benefit from the noise-averaging effect of multiple pixels while maintaining a relatively simple structure through shared connections and common readout pathways
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 design effectively suppresses noise and eliminates longitudinal streak noise, enhancing the signal-to-noise ratio and stability of the reference potential, allowing for improved infrared image sensing.
Implementation Method 1
an infrared absorption film to absorb the incident infrared rays and convert the incident infrared rays to heat
Implementation Method 2
converts a temperature change in a heat sensitive part caused by feeble heat to an electric signal by using some thermoelectric conversion element
Data Source
AI summary
An infrared solid-state image sensor comprises:a pixel area comprising a sensitive pixel area where infrared detection pixels are arranged in a matrix form to detect incident infrared rays on the semiconductor substrate and a reference pixel area where reference pixels are provided, each of the infrared detection pixels comprising a thermoelectric conversion part, the thermoelectric conversion part comprising an infrared absorption film to absorb the incident infrared rays and convert the incident infrared rays to heat and a first thermoelectric conversion element to convert the heat obtained by the conversion in the infrared absorption film to a electric signal, each of the reference pixels comprising a second thermoelectric conversion element. Each of first ends of the reference pixels are connected to a reference potential line, and a difference between the signal potential read out from a corresponding signal line and a reference potential supplied from the reference potential line is amplified and outputted.