Multi-Electrode Image Sensor Pixels for Global Shutter and Crosstalk Reduction
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Solution Overview
Problem
Conventional image sensors face issues with rolling shutter artifacts due to differing integration times across rows, leading to exposure location discrepancies, and suffer from electrical crosstalk between adjacent pixel electrodes, which affects the accuracy of light detection and image capture.
Innovation Solution
The implementation of a multi-electrode control system in image sensors, where a first electrode is in electrical communication with an optically sensitive layer, and additional electrodes provide biasing and photocurrent collection, allowing for global electronic shutter operation and reduced electrical crosstalk through careful timing and biasing of electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rolling shutter readout is used to simplify circuit design, then device complexity is reduced, but measurement precision deteriorates due to exposure location discrepancies
Solution Approach 1:
The patent divides the pixel array into multiple independently controllable rows, each with its own electrode and integration timing. This segmentation allows different rows to be exposed simultaneously (global shutter effect) while maintaining simplified per-pixel circuitry, resolving the contradiction between circuit simplicity and exposure timing accuracy.
Solution Approach 2:
The patent implements dynamic control of electrode biasing voltages to enable flexible integration timing for different rows. By dynamically adjusting the biasing conditions and integration windows, the system achieves global shutter functionality with simplified circuits, improving measurement precision without significantly increasing device complexity.
2Productivity
If adjacent pixel electrodes are placed close together to increase pixel density, then productivity is improved, but electrical crosstalk increases reducing measurement precision
Solution Approach 1:
The patent introduces additional electrodes positioned between adjacent pixel electrodes that serve as electrical shields or intermediaries. These intermediate electrodes, when properly biased, reduce electrical crosstalk between neighboring pixels, allowing higher pixel density while maintaining light detection accuracy.
Solution Approach 2:
The patent dynamically adjusts the biasing voltage parameters of electrodes during different operational phases (integration, readout, reset). By changing voltage parameters in real-time, the system minimizes electrical crosstalk between adjacent pixels while maintaining high pixel density, thus improving measurement precision without sacrificing productivity.
3Measurement precision
If additional electrodes are added for global shutter control, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent designs additional electrodes to serve multiple functions: they act as collection electrodes for photocurrent, provide electrical shielding between pixels, and enable global shutter control through coordinated biasing. This multi-functionality improves measurement precision while minimizing the increase in device complexity by avoiding dedicated single-purpose components.
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 approach enables consistent exposure timing across all rows, minimizing rolling shutter artifacts and significantly reducing electrical crosstalk, resulting in improved light detection accuracy and image quality.
Implementation Method 1
an optically sensitive layer; where a first electrode is in electrical communication with the optically sensitive layer
Data Source
AI summary
Various embodiments include methods and apparatuses for forming and using pixels for image sensors. In one embodiment, an image sensor is disclosed. The image sensor includes an optically sensitive material; a plurality of electrodes proximate the optically sensitive material, including at least a first electrode, a second electrode and a third electrode; and a charge store. The first electrode is coupled to the charge store, and the first electrode and the second electrode are configured to provide a bias to the optically sensitive material to direct photocarriers to the charge store. Other methods and apparatuses are disclosed.