Image Sensor Feedback Device for Noise Reduction During Reset
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Solution Overview
Problem
Semiconductor-based image sensors with multiple photoelectric devices suffer from noise interference, affecting the accuracy of captured images due to noise components in the reset voltage and pixel voltage.
Innovation Solution
An image sensor design that includes a photoelectric device generating an electric charge from light, a feedback device for generating a reset voltage, and a pixel circuit to set and output pixel and reset voltages during specific periods, allowing for accurate detection and minimization of noise components through a feedback technique and separate operational periods for feedback reset and read-out modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photoelectric devices are included in each pixel to capture different colors, then the image sensor can capture color information, but noise components in the reset voltage adversely affect image quality
Solution Approach 1:
The patent divides the pixel array into two separate groups: first pixels that output only reset voltage and second pixels that output only pixel voltage. This segmentation allows the reset voltage from first pixels to be used as a reference for subtracting noise from the pixel voltage of second pixels, thereby eliminating noise interference while preserving color capture capability through multiple photoelectric devices
Solution Approach 2:
The patent introduces first pixels as intermediary elements that generate reset voltage without capturing image information. This intermediary reset voltage serves as a reference signal that mediates the noise removal process, allowing accurate extraction of pixel voltage from second pixels by subtracting the reset voltage component
2Productivity
If reset voltage is output simultaneously with pixel voltage during the same horizontal period, then the read-out operation can be completed in one period, but noise components cannot be effectively separated
Solution Approach 1:
The patent segments the pixel array into first pixels for reset voltage output and second pixels for pixel voltage output. This segmentation enables the sampling circuit to detect reset voltage from first pixels and pixel voltage from second pixels separately, allowing effective noise separation while maintaining efficient read-out operation within the same horizontal period
3Stability of the object's composition
If feedback device is used to generate reset voltage using reference voltage, then the reset voltage can be stabilized, but the device complexity increases
Solution Approach 1:
The patent employs a feedback device in each pixel circuit that automatically generates stable reset voltage using a reference voltage. The feedback mechanism self-regulates to maintain consistent reset voltage levels across all pixels, providing voltage stability while using a standardized circuit design that can be replicated across the pixel array
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 minimizes noise interference, enabling accurate detection and output of pixel and reset voltages, thereby improving image quality by ensuring consistency and reducing noise components in the image sensor's output.
Implementation Method 1
a photoelectric device configured to generate an electric charge from light
Data Source
AI summary
An image sensor includes a photoelectric device generating an electric charge from light; a feedback device generating a reset voltage using a predetermined reference voltage; and a pixel circuit generating a pixel voltage using the reset voltage and the electric charge, setting the reset voltage to the reference voltage using the feedback device a first period, and outputting the pixel voltage and the reset voltage during a second period.