Solid-State Imaging Element Luminance Correction via Vertical OPB Arrangement
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Solution Overview
Problem
Existing solid-state imaging elements face challenges in accurately correcting uneven luminance (streaks) while maintaining a compact size, as adding optical black (OPB) pixels for correction either increases the device size or reduces accuracy due to insufficient OPB pixel signals.
Innovation Solution
Incorporating a pixel array unit with a scanning circuit and analog-to-digital conversion units that output more analog signals than pixels, including effective and reference signals, to perform black level correction processing, allowing for accurate streak correction without enlarging the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical black (OPB) pixels are arranged on the left and right sides of the pixel array to correct streaks, then uneven luminance correction is improved, but the device size increases in the left-right direction
Solution Approach 1:
The patent changes the arrangement dimension of OPB pixels from horizontal (left-right) to vertical (up-down). Specifically, OPB pixels are arranged in the up-down direction at the left and right ends of the pixel array, allowing multiple OPB pixels to be positioned vertically along the same horizontal column. This dimensional reconfiguration enables sufficient OPB pixel count for accurate streak correction without increasing the horizontal device width.
Solution Approach 2:
The patent makes the OPB pixels multi-functional by having them serve both as reference pixels for black level correction and as part of the overall pixel array structure. The same OPB pixels arranged vertically provide reference signals for multiple correction purposes while occupying minimal horizontal space, thus achieving universal utility without device expansion.
2Length of stationary object
If the number of OPB pixels is reduced to downsize the solid-state imaging element, then device size is reduced, but correction accuracy deteriorates due to insufficient OPB pixel signals
Solution Approach 1:
By arranging OPB pixels vertically in the up-down direction rather than horizontally, the patent increases the effective number of OPB pixels available for correction without increasing the horizontal device footprint. This vertical stacking allows sufficient OPB pixel signals to be collected while maintaining a compact overall device size.
3Measurement precision
If more analog-to-digital converters are arranged to process more analog signals, then correction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs the analog-to-digital conversion unit to handle multiple types of signals (effective pixel signals and reference signals from OPB pixels) through a unified conversion architecture. The same ADC infrastructure serves dual purposes: converting effective pixel signals for image formation and converting reference signals for black level correction, thereby improving correction accuracy without proportionally increasing device complexity.
Data Source
AI summary
The present technology is provided to accurately correct uneven luminance while suppressing an increase in the size of the solid-state imaging element. A pixel array unit includes a plurality of lines each including a predetermined number of pixels each being arrayed in a predetermined direction. An analog-to-digital conversion unit includes more than the predetermined number of analog-to-digital converters that convert analog signals into digital signals. A scanning circuit controls to sequentially select the plurality of lines and output more than the predetermined number of analog signals to the analog-to-digital conversion unit every time the line is selected. A correction unit performs black level correction processing on the digital signal.