Image Sensor Bit-Memory Switching for Defect-Tolerant A/D Columns
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in suppressing the increase in circuit area due to the provision of data switching units in each column AD circuit, which can lead to a decrease in image quality when defects occur in the data holding units.
Innovation Solution
The implementation of a switching unit that selectively reroutes bit signals across multiple memory units, allowing the image pickup apparatus to maintain data integrity and reduce circuit area by shifting bit positions in response to defects, thereby preventing data deficits and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data switching units are provided in each column AD circuit to suppress data deficit caused by defects, then image quality is maintained, but circuit area increases
Solution Approach 1:
The patent merges the data switching functionality from multiple column-specific switching units into a single common switching unit that serves all column AD circuits. This consolidation maintains the defect compensation capability while reducing the total circuit area by eliminating redundant switching components in each column.
Solution Approach 2:
The common switching unit is designed to handle data from multiple column AD circuits universally, performing the defect compensation function for any column rather than being dedicated to a single column. This multi-functional approach allows one switching unit to replace multiple column-specific units.
2Reliability
If bit shifting is performed to compensate for defects in data holding units, then data integrity is maintained, but device complexity increases
Solution Approach 1:
The common switching unit acts as an intermediary between the column AD circuits and the data holding units. It mediates the data flow by performing bit shifting operations to redirect data when defects are detected, centralizing the complexity management in one component rather than distributing it across multiple column circuits.
Solution Approach 2:
The system changes the bit position parameter of the data by performing bit shifting operations. When a defect is detected in a data holding unit, the switching unit shifts the bits of the data to different positions, allowing the data to be stored in alternative holding units with different bit configurations, thus maintaining data integrity.
Data Source
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AI summary
The present invention relates to a technology for providing selection means (107) configured to perform selection of a bit memory that holds a signal of a first bit of a digital signal from among a plurality of bit memories commonly in memory means (104) in each of a plurality of AD conversion means (102, 104).