Staggered Shared-Pixel Layout for Back-Illuminated Global Shutters
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Solution Overview
Problem
Back-illuminated CMOS image sensors with global shutter function face challenges in maintaining image quality due to optical characteristic differences between pixel regions, leading to decreased image quality.
Innovation Solution
The imaging device incorporates shared sections with pixel regions aligned such that those receiving the same color light have their components shifted by one pixel region in the X-axis direction, reducing optical characteristic differences and enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pixel regions are arranged in a conventional grid pattern, then device complexity is reduced and manufacturing is easier, but optical characteristic differences between pixel regions cause image quality degradation
Solution Approach 1:
The patent applies asymmetry by shifting the arrangement of shared sections in the second direction relative to pixel regions in the first direction. Specifically, shared sections are positioned at offsets such that a shared section at position (i, j) serves pixel regions at (i, j), (i, j+1), (i+1, j), and (i+1, j+1), creating an asymmetric mapping that equalizes optical path lengths and reduces optical characteristic differences between pixel regions of the same color.
2Manufacturing precision
If components are aligned to reduce optical characteristic differences, then image quality is improved, but device complexity increases due to shifted shared section arrangement
Solution Approach 1:
The patent merges multiple pixel regions to share common readout circuitry through shared sections. Each shared section combines signal processing functions for four adjacent pixel regions (2x2 pattern), reducing the total number of independent readout paths and equalizing optical characteristics by ensuring symmetric light path geometry for all pixel regions served by that shared section.
3Device complexity
If shared sections serve multiple pixel regions, then device complexity is reduced, but optical characteristic differences between pixel regions lead to image quality decrease
Solution Approach 1:
The patent introduces a dimensional offset in the arrangement of shared sections by shifting their positions in the second direction relative to the pixel region grid in the first direction. This dimensional displacement creates an asymmetric mapping pattern where shared sections serve pixel regions in a staggered configuration, equalizing optical path lengths and eliminating optical characteristic differences while maintaining shared readout circuitry.
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 configuration effectively suppresses the decrease in image quality caused by optical characteristic differences, particularly in back-illuminated sensors, by aligning components to receive consistent light, resulting in improved image fidelity.
Implementation Method 1
a photoelectric converter provided for each of the pixel regions
Data Source
AI summary
An imaging device including an imaging unit in which a plurality of shared sections each including two pixel regions adjacent at least in a first direction is provided and the shared sections provided at closest positions in a second direction are disposed to shift in the first direction by the one pixel region, a photoelectric converter provided for each of the pixel regions, an electric charge holding unit that holds signal charge generated by the photoelectric converter, an electric charge voltage converter to which the signal charge is transferred from the electric charge holding unit, and a pixel transistor that is electrically coupled to the electric charge voltage converter. The second direction intersects the first direction. The pixel transistor is provided for each of the shared sections.