Sensor Background Signal Suppression via Differential Accumulation
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Solution Overview
Problem
Existing sensors face challenges in accurately detecting desired signals due to large background signals, which can lead to saturation and make it difficult to distinguish between the desired and background signals, especially in applications like infrared imaging, fluorescence imaging, and time-of-flight 3D image sensors.
Innovation Solution
A sensor system that includes a pixel array, an accumulator, and a digital memory, where the accumulator converts differential signals between detected signals into digital form and accumulates them, using cross-sampling on different circuits to prevent saturation and store the signals in digital memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor uses a temporal or spatial differential readout circuit to suppress background signal, then background signal suppression is improved, but saturation occurs when background signal intensity is high or sensing time is long
Solution Approach 1:
The sensor divides the pixel array into multiple regions (e.g., first region and second region) and uses separate readout circuits for each region. This segmentation allows independent processing of signals from different spatial locations, enabling background suppression while preventing saturation through regional differentiation.
Solution Approach 2:
The patent introduces a temporal dimension by performing multiple measurements at different time points and combining results. By measuring signals at different times and processing them through separate readout circuits, the system achieves background suppression without saturation while maintaining measurement accuracy.
2Measurement precision
If a sensor increases sensing time to improve signal detection, then signal detection capability is improved, but background signal accumulation causes saturation
Solution Approach 1:
The sensor performs periodic measurements at multiple time points rather than continuous accumulation. By taking discrete measurements at different times and processing them through separate readout circuits, the system maintains detection capability while preventing background signal accumulation from causing saturation.
Solution Approach 2:
The measurement process is divided into multiple temporal segments with separate readout circuits handling different time intervals. This temporal segmentation allows the system to process signals from different periods independently, improving detection while avoiding saturation from prolonged accumulation.
3Device complexity
If a sensor uses a single readout circuit to process all pixel signals, then device complexity is reduced, but background signal suppression performance deteriorates
Solution Approach 1:
The readout circuit is segmented into multiple independent processing paths, each handling signals from specific pixel regions or time intervals. This segmentation enables background suppression through differential processing while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The multiple readout circuits perform multiple functions: they simultaneously process signals from different spatial regions, implement background suppression through differential measurement, and prevent saturation through independent processing. This multi-functionality justifies the increased complexity by delivering superior performance.
Data Source
AI summary
A sensor for suppressing a background signal is provided. The sensor includes: a pixel array that detects a signal by using a plurality of pixels; an accumulator that converts a differential signal between two signals detected from an arbitrary pixel of the pixel array at predetermined times into a digital signal and accumulates the digital signal; and a digital memory that stores the accumulated digital signal.