Image Sensor Color Filter Arrays with Zone-Specific Properties
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Solution Overview
Problem
Conventional image sensors with fixed color filter patterns, such as the Bayer mosaic, limit image sensor performance as they do not adapt to varying image capture requirements across different parts of the sensor array, leading to suboptimal performance in applications like vehicle safety systems where different zones of the image sensor need tailored imaging attributes.
Innovation Solution
The implementation of color filter arrays with varying properties across the image sensor array, where each pixel's color filter elements have different structures based on their distance from the center, incorporating additional transparent or opaque portions within the passivation or composite grid layers to alter light response, allowing for optimized imaging performance in specific zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed color filter pattern (Bayer mosaic) is used across the entire sensor array, then manufacturing simplicity is maintained, but image sensor performance is limited in applications requiring zone-specific imaging attributes
Solution Approach 1:
The patent applies local quality by implementing different color filter properties in different zones of the sensor array. Specifically, a first color filter is used in a first zone and a second color filter with different properties is used in a second zone, allowing each zone to be optimized for its specific imaging requirements rather than using a uniform pattern across the entire array.
Solution Approach 2:
The sensor array is segmented into multiple zones with different color filter configurations. The array is divided such that certain regions have access to multiple color filter types, enabling independent optimization of imaging characteristics for different functional areas of the sensor.
2Reliability
If additional transparent or opaque portions are incorporated within passivation or composite grid layers to alter light response, then imaging performance in specific zones is optimized, but manufacturing complexity increases
Solution Approach 1:
The patent implements nesting by incorporating transparent or opaque portions within the passivation or composite grid layers that are already part of the sensor structure. These additional portions are nested within existing structural elements rather than requiring completely separate fabrication processes, allowing performance optimization while leveraging the existing manufacturing framework.
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 enhances image sensor performance by tailoring the color filter properties to specific zones, improving low light sensitivity, color accuracy, and modulation transfer function, thereby addressing the limitations of fixed color filter patterns and enhancing image capture in diverse applications.
Implementation Method 1
Each pixel receives incident photons (light) and converts the photons into electrical signals
Implementation Method 2
Each image pixel in the array includes a photodiode that is coupled to a floating diffusion region via a transfer gate. Each pixel receives incident photons (light) and converts the photons into electrical signals
Data Source
AI summary
Color filters may affect imaging performance attributes such as low light sensitivity, color accuracy, and modulation transfer function (MTF). In an image pixel array, these factors are influenced by both the spectral absorption and pattern of the color filter elements. Different portions of an image sensor may prioritize different imaging performance attributes. Accordingly, in certain applications it may be beneficial for color filter characteristics to vary across an image sensor. Different color filters of the same color may have different structures to optimize imaging performance across the image sensor.