Image Sensor Capacitance Configuration for Crosstalk Reduction
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Solution Overview
Problem
Crosstalk occurs in AD conversion units due to voltage variations in the input capacitance of comparators, leading to noise interference in images displayed on a display device.
Innovation Solution
An image sensor design that includes specific capacitance configurations and switching elements to balance the input capacitance for pixel and reference signals, reducing interference between adjacent AD conversion units by varying the arrangement of split capacitors in odd and even column regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If AD conversion units are arranged closely in parallel rows to increase integration density, then device area is reduced, but crosstalk occurs between adjacent units causing image noise
Solution Approach 1:
The patent applies asymmetry by arranging an odd number of capacitances (three or five) in the first row and an even number (two or four) in the second row, creating asymmetric patterns that break the symmetry of interference fields between adjacent AD conversion units, thereby reducing crosstalk while maintaining compact integration
Solution Approach 2:
The patent segments the capacitances into multiple individual units (C1, C2, C3 in first row; C4, C5 in second row) that can be independently controlled through switching elements, allowing selective connection to balance input capacitance values and reduce interference between adjacent columns
2Measurement precision
If input capacitance is increased to improve signal holding capacity, then signal-to-noise ratio is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic control of input capacitance through switching elements that can connect or disconnect individual capacitance units based on signal conditions, allowing the total input capacitance to be adjusted dynamically to balance signal-to-noise ratio requirements against power consumption constraints
Solution Approach 2:
The patent changes the effective input capacitance parameter by selectively connecting different numbers and combinations of capacitance units (C1-C5) through switching elements, enabling optimization of the capacitance value to achieve desired signal-to-noise ratio while minimizing power consumption
3Extent of automation
If voltage variation in input capacitance is used for AD conversion operation, then conversion function is achieved, but interference is transmitted to adjacent units
Solution Approach 1:
The patent converts the potentially harmful voltage variation in input capacitance into a beneficial balancing mechanism by using switching elements to connect different capacitance units in specific patterns, where the same voltage variation affects multiple units in a way that cancels out interference when summed across the differential input
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
The image sensor effectively reduces crosstalk, maintaining a balanced input dynamic range and lowering power consumption while preventing image quality degradation from noise interference.
Implementation Method 1
a first pixel including a photoelectric conversion element
Data Source
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AI summary
It is an object of the present technology to provide an image sensor capable of reducing crosstalk in an AD conversion unit. The image sensor includes: capacitors in an even-numbered column region; and a capacitor in an odd-numbered column region disposed facing the capacitors in the even-numbered column region with different areas.