Pseudo-Thinning-Out Pixel Driving for CMOS Image Sensors
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Solution Overview
Problem
Current CMOS image sensors face challenges in achieving high-speed reading without deteriorating image quality, particularly in flexible pixel thinning-out methods which often result in reduced image quality.
Innovation Solution
A solid-state imaging device with a pixel section and a pixel driving section that enables pseudo multi-row thinning-out addition reading by alternately reading pixel columns, allowing for flexible thinning-out without physically thinning out pixels in a reading target row, thereby maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional thinning-out reading is performed to achieve high-speed reading, then reading speed is improved, but image quality deteriorates
Solution Approach 1:
The pixel array is divided into multiple column groups, and different reading modes (normal reading and thinning-out reading) are applied to different column groups. This segmentation allows simultaneous execution of high-speed thinning-out reading for some columns while maintaining high-quality normal reading for others, resolving the contradiction between reading speed and image quality.
Solution Approach 2:
The reading mode is made dynamic and adjustable, allowing the system to switch between normal reading mode and thinning-out reading mode for different column groups based on requirements. This dynamic flexibility enables optimization of both reading speed and image quality by adapting the reading strategy to different scenarios.
2Manufacturing precision
If all pixels are read to maintain image quality, then image quality is preserved, but reading speed decreases
Solution Approach 1:
The pixel array is segmented into multiple column groups that can be read in parallel. By dividing the reading task across multiple columns simultaneously, the overall reading speed is increased while all pixels remain available for reading, thus maintaining image quality without sacrificing speed.
Solution Approach 2:
The system enables continuous high-speed reading by utilizing all pixels through parallel column-parallel reading operations. The column-parallel output architecture allows multiple columns to be read simultaneously, maintaining continuous useful action across the entire pixel array without interruption or thinning-out.
3Productivity
If column-parallel output is used to increase data rate, then productivity is improved, but device complexity increases
Solution Approach 1:
The pixel circuit is designed with multi-functionality, where the same pixel structure and amplification circuitry serve both normal reading and thinning-out reading operations. The pixel circuit can adaptively output to different column groups based on the selected reading mode, eliminating the need for separate dedicated circuits for each reading type and thus avoiding increased device complexity.
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
Enables flexible thinning-out operations equivalent to traditional methods like ⅔ or ⅗ thinning-out without degrading image quality, allowing for high-speed reading while utilizing all pixels effectively.
Implementation Method 1
The photoelectric conversion device 11 photoelectrically converts incident light into electric charges (here electrons) of which the amount corresponds to the amount of the light.
Data Source
AI summary
A solid-state imaging device includes: a pixel section in which a plurality of pixels converting optical signals into electric signals and accumulating the electric signals in accordance with an exposure period are arranged in a matrix shape; and a pixel driving section that is able to drive the pixel section to perform reset thereof and accumulate and output the electric signals, wherein the pixel driving section includes a vertical reading function of alternately reading pixel columns for which addition is vertically performed and pixel columns for which the addition is not performed, and a column reading function of changing the addition and normal reading whenever reading each single row in response to scanning of the vertical reading circuit, and the pixel driving section performs pseudo thinning-out reading addition equivalent to thinning-out by reading all pixels without thinning out pixels in a reading target row.