Image Sensor Row Drive Circuit Timing Synchronization
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Solution Overview
Problem
Existing image sensing devices face challenges in reducing the size while minimizing the timing difference in signal delivery to pixels, leading to increased circuit scale and size.
Innovation Solution
The design incorporates a pixel array with row drive and assist circuits, featuring control lines driven by a row drive circuit and assist circuit, which includes first and second drive circuits connected to the ends of control lines to synchronize signal timing across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two vertical scanning circuits are arranged to sandwich the region below pixels, then signal timing synchronization is improved, but device size increases
Solution Approach 1:
The patent divides the control signal distribution function into two parts: the main vertical scanning circuit provides control signals to most pixels, while assist circuits are selectively placed only at specific positions (second end of control lines) to synchronize timing for pixels that require it. This segmented approach maintains timing synchronization without duplicating the entire vertical scanning circuit, thereby reducing device size while improving signal timing synchronization.
2Area of stationary object
If circuit scale is reduced, then device size decreases, but signal timing difference between pixels increases
Solution Approach 1:
The patent introduces assist circuits as intermediary components that act as buffer amplifiers at strategic positions in the control signal path. These assist circuits compensate for signal timing differences that would otherwise occur in a reduced-scale circuit configuration. By placing assist circuits at the second end of control lines, the patent ensures that pixels at different positions receive control signals at synchronized timings, maintaining manufacturing precision while allowing overall circuit scale reduction.
Data Source
AI summary
An image sensing device includes pixels forming rows and columns, sets of control lines respectively assigned to the rows such that one set of control lines is connected to one of the rows, a row drive circuit configured to drive the sets of control lines, and an assist circuit. Each set includes a first control line and a second control line. The row drive circuit includes a first drive circuit connected to a first end of the first control line and a second drive circuit connected to first end of the second control line. The assist circuit includes an assist drive circuit connected to a second end of the first control line so as to drive the first control line in accordance with a control signal supplied to the second control line.