Variable Pixel Separation in Image Sensors for Cross-Talk Control
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Solution Overview
Problem
Current image sensors face challenges in achieving clear image quality due to limitations in pixel separation and light blocking patterns, which affect light absorption and quantum efficiency.
Innovation Solution
The image sensor design incorporates distinct pixel separation portions with varying widths and light blocking patterns to optimize light reception and reduce absorption, featuring conductive patterns with different widths and insulating materials to enhance light efficiency and reduce dark current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel separation portions are made wider to improve light blocking and reduce cross-talk between pixels, then light absorption and quantum efficiency deteriorate
Solution Approach 1:
The patent applies different widths to different pixel separation portions based on their local requirements. The first pixel separation portion (between first and second unit pixels) has a first width, while the second pixel separation portion (between second and third unit pixels) has a second width that is less than the first width. This local differentiation allows optimal cross-talk reduction where needed while preserving light reception in other areas.
Solution Approach 2:
The pixel separation structure is segmented into multiple distinct portions with different dimensions. Rather than using a uniform separation width across all pixel boundaries, the patent divides the separation structure into at least two types: first pixel separation portions with a first width and second pixel separation portions with a second width, enabling differentiated optimization for different pixel pairs.
2Reliability
If conductive patterns are made wider to improve electrical connectivity and reduce dark current, then light absorption increases and quantum efficiency decreases
Solution Approach 1:
The conductive patterns within pixel separation portions are designed with varying widths according to local electrical requirements. Some pixel separation portions contain conductive patterns with larger widths for better electrical connectivity, while others have narrower or no conductive patterns to minimize light absorption. This local quality differentiation resolves the contradiction between electrical performance and optical efficiency.
Solution Approach 2:
The conductive pattern distribution is segmented rather than uniform. The patent selectively places conductive patterns in certain pixel separation portions while omitting them or using narrower patterns in others, creating a segmented electrical connectivity structure that optimizes both dark current reduction and light reception based on specific structural needs.
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 improves light reception, quantum efficiency, and photosensitivity, leading to enhanced image quality and auto-focus performance by minimizing light absorption and dark current.
Implementation Method 1
The photodiode may convert incident light into an electrical signal
Data Source
AI summary
An image sensor includes a substrate having opposite first and second surfaces and including first to third unit pixels arranged in a first direction, and first and second pixel separation portions in the substrate and between, and separating from each other, separate adjacent unit pixels of the first to third unit pixels. The first pixel separation portion includes a first conductive pattern, and a first separation insulating pattern covering a sidewall of the first conductive pattern. The second pixel separation portion includes a second conductive pattern, and a second separation insulating pattern covering a sidewall of the second conductive pattern. The first conductive pattern has a first width in the first direction, and the second conductive pattern has a second width in the first direction, which is less than the first width.