Pixel Array Signal-Line Layout for High-Density Image Readout
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Solution Overview
Problem
The structure of existing solid-state imaging devices faces challenges in increasing pixel density, leading to lower frame rates and increased cross-talk due to reduced pixel pitch, which necessitates a reduction in frame rate to maintain signal integrity.
Innovation Solution
The implementation of a pixel array with two signal lines per column, where the signal lines and a shield line are arranged along the row direction, allowing simultaneous readout of pixel signals and minimizing cross-talk, thereby maintaining frame rate even with increased pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pixel pitch is reduced to increase the number of pixels, then pixel density increases, but frame rate decreases due to increased readout time
Solution Approach 1:
The pixel array is divided into multiple banks, with each bank having its own independent readout circuitry. This segmentation allows parallel readout of multiple pixel groups simultaneously, thereby maintaining frame rate even as the total number of pixels increases through reduced pixel pitch.
Solution Approach 2:
The patent introduces a bank dimension to the traditional row-column pixel organization. By adding this fourth dimension (bank index), the readout process can proceed in parallel across multiple banks, effectively increasing the readout bandwidth without changing the physical pixel pitch.
2Quantity of substance
If pixel pitch is reduced to increase the number of pixels, then pixel density increases, but cross-talk increases due to shortened distances between lines
Solution Approach 1:
Shield lines are introduced as intermediary structures between adjacent signal lines. These shield lines act as electromagnetic barriers that intercept and redirect interference signals, thereby reducing cross-talk between neighboring pixels even when the pixel pitch is reduced to increase pixel density.
Solution Approach 2:
The patent applies different structural characteristics to different regions of the pixel array. Specifically, shield lines are strategically positioned between signal lines in high-density regions to provide localized cross-talk mitigation, allowing the overall pixel pitch to be reduced without uniformly increasing interference across the entire array.
3Quantity of substance
If the number of signal lines is increased to support more pixels, then pixel density increases, but device complexity increases
Solution Approach 1:
Multiple signal lines are merged into shared signal lines that serve multiple pixel banks. By combining the readout functions of several banks into common signal paths, the total number of signal lines is reduced, thereby decreasing device complexity while still supporting a high number of pixels through the banked architecture.
Solution Approach 2:
Signal lines are designed to serve multiple functions and multiple pixel banks simultaneously. A single signal line can carry readout signals from multiple banks at different times or in parallel, making the signal line structure more universal and reducing the overall count of required signal lines, thus lowering 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
This configuration enables simultaneous readout of pixel signals from adjacent rows, preventing a decrease in frame rate and effectively reducing cross-talk, allowing for higher frame rates and improved signal integrity as pixel density increases.
Implementation Method 1
light collected by a lens 502 passes through a color filter 503 that is transmissive to specific wavelengths, and produces holes in the photoelectric conversion film 505
Data Source
AI summary
An imaging device incudes a pixel array including pixels arranged in columns and rows, one of the columns including a first pixel in a first row and a second pixel in a second row; a first signal line, to which the first pixel is coupled, and a second signal line, to which the second pixel is coupled, extending in a column direction of the pixels; and a first shield line, to which the first pixel is coupled, extending in the column direction. The first signal line, the first shield line, and the second signal line are arranged along a row direction of the pixels in that order.