Image Sensor Color Filter Isolated Partitions for Quantum Efficiency
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Solution Overview
Problem
Image sensors face challenges in enhancing quantum efficiency (QE) for high dynamic range applications, particularly under varying illumination conditions, as existing color filter layers do not effectively optimize QE across different color segments.
Innovation Solution
Incorporating isolated partitions in the color filter array with a refractive index lower than the surrounding color filters, which surround specific color filters, creating a total reflective structure to enhance QE peaks for red, green, and blue pixels, and optionally infrared filters, thereby improving the dynamic range capabilities of image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a connected color filter layer is used, then the manufacturing process is simplified, but the quantum efficiency of pixels varies across different color segments
Solution Approach 1:
The color filter layer is divided into isolated partitions corresponding to different color segments (red, green, blue). Each partition is separated by gaps filled with low refractive index material, creating independent optical paths for each color. This segmentation allows different QE optimization for each color while maintaining manufacturing simplicity.
Solution Approach 2:
Different regions of the color filter layer are given different properties through the isolated partition structure. Each color segment (R, G, B) has its own partition with specific optical characteristics, allowing local optimization of quantum efficiency for each color while maintaining overall manufacturing efficiency.
2Manufacturing precision
If a grid structure is introduced to form discontinuous color filter layer, then the quantum efficiency can be optimized, but the device complexity increases
Solution Approach 1:
A low refractive index material is introduced as an intermediary substance filling the gaps between color filter segments. This intermediary material creates the necessary optical isolation and total internal reflection conditions without requiring complex structural modifications, thus optimizing QE while maintaining relatively simple device architecture.
Solution Approach 2:
The refractive index parameter is strategically changed by introducing low refractive index material in the gaps between color filter partitions. This parameter change enables total internal reflection at the interfaces, confining light within each color segment and enhancing quantum efficiency without complex structural changes.
3Reliability
If the quantum efficiency is enhanced for high dynamic range application, then the image quality under varying illumination is improved, but additional structural elements are required
Solution Approach 1:
The filter array is segmented into isolated partitions for different color segments, allowing independent optimization of quantum efficiency for each color. This segmentation enables enhanced high dynamic range performance by preventing cross-color light interference while maintaining a relatively simple overall structure.
Solution Approach 2:
Low refractive index material serves as an intermediary element between color filter segments, creating optical isolation and enabling total internal reflection. This intermediary structure enhances quantum efficiency and high dynamic range performance without requiring complex additional 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
The isolated partitions enhance the quantum efficiency of specific pixel types, leading to improved image capture quality under high dynamic range conditions by optimizing the refractive structures at the interface between the partitions and color filters, thus enhancing the overall performance of image sensors.
Implementation Method 1
The isolated partition has a refractive index that is lower than the refractive indexes of the first, second and third color filters... forming a total reflective structure at the interface
Data Source
AI summary
An image sensor is provided. The image sensor includes a semiconductor substrate containing a plurality of photoelectric conversion elements. A color filter array is disposed above the semiconductor substrate. The color filter array includes a first color filter, a second color filter and a third color filter. The image sensor further includes an isolated partition disposed in the color filter array to surround one of the first, second and third color filters. The isolated partition has a refractive index that is lower than the refractive indexes of the first, second and third color filters.