RGBW Image Sensor Pixel Array for Crosstalk-Free Signal Readout
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Solution Overview
Problem
The RGBW3.0 color filter array (CFA) has undergone significant structural changes compared to conventional CFAs, leading to a lack of corresponding pixel signal processing circuits, which impedes accurate control and application in complementary metal-oxide semiconductor (CMOS) image sensors (CIS).
Innovation Solution
A novel pixel circuit array architecture for RGBW3.0 CFA is introduced, where each pixel cluster includes one white pixel surrounded by multiple color pixels, with shared control and output signal lines, and a pixel signal processing module that includes selection, amplification, and analog-to-digital conversion modules to process signals from white and color pixels independently, avoiding signal crosstalk and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a five-pixel color filter array (RGBW3.0) is developed to address disadvantages in conventional CFA architectures, then color resolution and sensitivity are improved, but device complexity increases due to major structural changes and lack of corresponding pixel signal processing circuits
Solution Approach 1:
The pixel array is divided into multiple pixel clusters, with each cluster containing one white pixel circuit and at least two color pixel circuits arranged in specific patterns (e.g., RGB clusters or GB clusters). This segmentation allows independent signal processing for white and color pixels while maintaining the advanced RGBW3.0 color filter benefits, thus improving color resolution without overwhelming system complexity
Solution Approach 2:
The pixel signal processing module is designed with universal functionality to handle both white pixel signals and color pixel signals through the same readout circuitry. The module can selectively process signals from different pixel types using shared amplification and analog-to-digital conversion resources, reducing overall device complexity while maintaining support for the enhanced RGBW3.0 architecture
2Reliability
If pixel circuits are arranged in clusters with shared control and output signal lines to improve sensitivity, then signal processing efficiency is improved, but signal crosstalk between color and white pixels increases
Solution Approach 1:
Within each pixel cluster, white pixel circuits and color pixel circuits are spatially segmented and assigned to different column groups. This segmentation allows the pixel signal processing module to selectively read out and process signals from white pixels or color pixels independently, maintaining high signal processing efficiency while preventing crosstalk between different pixel types through separate signal paths
Solution Approach 2:
The pixel signal processing module acts as an intermediary between the pixel circuit array and subsequent processing stages. It includes selection circuits that selectively connect to either white pixel output lines or color pixel output lines based on the current readout mode, thereby mediating signal flow to prevent crosstalk while maintaining efficient signal processing
3Device complexity
If conventional pixel signal processing circuits are used with RGBW3.0 CFA, then device complexity is reduced, but measurement precision and sensitivity deteriorate due to inability to accurately control and process the new pixel architecture
Solution Approach 1:
The pixel signal processing module is designed with local quality optimization, where specific processing paths and parameters are tailored for white pixel signals versus color pixel signals. This includes selective amplification gains, independent analog-to-digital conversion channels, and targeted noise filtering for each pixel type, thereby achieving high measurement precision without requiring completely separate processing systems
Solution Approach 2:
The pixel signal processing module employs dynamic control mechanisms that can adaptively switch between processing white pixel signals and color pixel signals based on the current operational mode. The selection circuits and processing parameters are dynamically adjusted to match the specific signal characteristics being processed, achieving high accuracy while maintaining manageable device complexity through flexible resource allocation
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 architecture enables accurate signal processing for RGBW3.0 CFAs in CMOS image sensors, facilitating wide application and improving sensitivity by avoiding signal interference between color and white pixels.
Implementation Method 1
a photosensitive element, such as a photodiode, converts light filtered by the color filter into an electrical signal
Data Source
AI summary
An image sensor includes a pixel circuit array, where the pixel circuit array includes a plurality of pixel cluster circuits. Each of the pixel cluster circuits includes one white pixel circuit and at least two color pixel circuits, and the at least two color pixel circuits are disposed around the white pixel circuit. The pixel circuit array includes at least two pixel circuit rows and at least two pixel circuit columns. The at least two pixel circuit rows share one control signal line, and the at least two pixel circuit columns share one output signal line, where the pixel circuit row includes the white pixel circuit or the color pixel circuit. The pixel circuit column includes the white pixel circuit or the color pixel circuit; and a pixel signal processing module, where the pixel signal processing module is connected to the output signal line.