Image Sensor Convex Substances and Notches for CRA Shading
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Solution Overview
Problem
The increasing chief ray angle (CRA) in compact electronic devices degrades image quality by causing lens shading and color shading issues in corner or edge pixels of image sensors, as the chief ray enters the filter unit at an angle, leading to inconsistencies in filtering performance.
Innovation Solution
The image sensor design includes a semiconductor substrate with a dielectric layer and a color filter set, where the center of the filter unit is intentionally offset from the center of the photosensitive unit, and the filter units are shaped with convex modeling and corresponding notches to ensure equal chief ray travel paths across all pixels, mitigating lens and color shading issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the image sensor is made smaller for compact electronic devices, then the device size is reduced, but the chief ray angle becomes larger causing lens shading and color shading issues
Solution Approach 1:
The patent applies local quality by making the filter units have different shapes for different pixels based on their position in the image sensor. Specifically, filter units for corner and edge pixels are designed with different geometries compared to center pixels, allowing each region to be optimized for its specific chief ray angle characteristics. This local customization enables consistent filtering performance across all pixels despite the varying CRA in compact sensor designs.
2Volume of moving object
If the chief ray angle increases in compact devices, then smaller device size is achieved, but filtering performance becomes inconsistent across pixels
Solution Approach 1:
The patent implements local quality by designing filter units with position-dependent characteristics. Each filter unit's shape is specifically tailored to its location on the image sensor, with corner pixels receiving different filter geometries compared to edge and center pixels. This ensures that despite the increased chief ray angle in compact devices, each pixel experiences optimized filtering conditions for its specific angular characteristics, maintaining consistent filtering performance across the entire sensor array.
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 design ensures consistent filtering performance across all pixels by equalizing the chief ray travel paths, thereby avoiding lens shading and color shading issues in corner and edge pixels, improving overall image quality.
Implementation Method 1
The convex substances and the notches change in accordance with the distance to the center of the image sensor, ensuring equal chief ray travel paths
Data Source
AI summary
An image sensor is provided in the present invention, including a plurality of optical elements, wherein each optical element includes a semiconductor substrate, a dielectric layer and a color filter set. The semiconductor substrate includes a plurality of photosensitive units. The dielectric layer is disposed above the semiconductor substrate and includes a plurality of notches. The color filter set is disposed above the dielectric layer and includes a plurality of filter units and a plurality of convex substances corresponding to the filter units, and the convex substances and the notches are engaged with each other, wherein the convex substances and the notches change in accordance with the distance to the center of the image sensor.