Imaging Device Differential Stage Noise Isolation
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Solution Overview
Problem
The existing imaging devices suffer from a decrease in analog-to-digital (AD) conversion accuracy due to kickback noise generated at the differential stage, which is transmitted to other stages, affecting the accuracy of comparison and signal conversion.
Innovation Solution
The implementation of a configuration where each set of the imaging device includes a photoelectric conversion portion, a floating diffusion portion, and a differential stage, with separate control lines for each set to prevent kickback noise from being transmitted between stages, thereby maintaining the accuracy of AD conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sets share common control lines, then device complexity is reduced, but kickback noise is transmitted between stages causing decreased AD conversion accuracy
Solution Approach 1:
The control lines are segmented into separate lines for different sets of pixel units. Specifically, first control lines are provided for odd-numbered pixel units and second control lines for even-numbered pixel units, preventing kickback noise transmission between sets while maintaining independent signal paths.
Solution Approach 2:
Different control line configurations are applied to different spatial locations or groups of pixel units. Odd-numbered units receive control signals through one path while even-numbered units receive them through another path, allowing localized optimization of noise isolation for each group.
2Reliability
If separate control lines are provided for each set, then kickback noise transmission is prevented, but device complexity and manufacturing cost increase
Solution Approach 1:
The pixel array is segmented into odd-numbered and even-numbered units with corresponding separate control lines, ensuring that kickback noise from one set cannot affect another set, thereby improving signal conversion reliability through physical signal path isolation.
Solution Approach 2:
While control lines are separated for noise isolation, the patent merges the overall control architecture by using a systematic naming and connection pattern (first control lines for odd units, second control lines for even units), which simplifies the manufacturing process compared to completely independent control circuits for each pixel unit.
3Object-affected harmful factors
If control lines are shared between pixel units, then wiring density is reduced, but noise interference increases affecting comparison accuracy
Solution Approach 1:
Control lines are divided into separate first and second control lines that serve different groups of pixel units (odd and even numbered respectively). This segmentation isolates noise sources so that kickback noise from one group cannot interfere with another group, reducing overall noise interference in the system.
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 prevents or reduces the decrease in AD conversion accuracy caused by kickback noise, ensuring higher precision in signal comparison and conversion by isolating noise transmission between stages.
Implementation Method 1
an imaging device including a photoelectric conversion portion and an AD conversion portion
Data Source
AI summary
In an imaging device, a differential stage includes an input transistor having an input node connected to a floating diffusion portion, a first control line and a second control line are located in a plurality of sets, the first control line is connected to connection portions of some sets of the plurality of sets, and the second control line is connected to connection portions of the other sets of the plurality of sets.