Pixel Array Layout for Accurate Phase Difference Detection
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Solution Overview
Problem
Existing solid-state imaging apparatuses face challenges in providing suitable phase difference pixels for improved phase difference detection, particularly in array patterns with systematically arranged shared pixels, where the sensitivity and accuracy of phase difference detection are compromised due to differing exposure times and the inability to adopt 2×1 on-chip lens structures.
Innovation Solution
The solution involves arranging phase difference pixels in a 2×1 on-chip lens structure within pixel groups, where each pixel group includes four pixels of the same color, allowing for adjusted exposure times and shared pixel circuits, thereby enhancing phase difference detection accuracy and sensitivity by dispersing phase difference pixels across adjacent groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phase difference pixels are arranged in a pixel array with systematically arranged shared pixels, then manufacturing efficiency is improved, but phase difference detection accuracy deteriorates due to differing exposure times
Solution Approach 1:
The pixel array is segmented into multiple pixel groups, where each group contains a specific arrangement of phase difference pixels and regular pixels. This segmentation allows different exposure times for phase difference pixels while maintaining systematic organization for efficient manufacturing.
Solution Approach 2:
Different regions of the pixel array are assigned different functions: phase difference pixels in specific positions have different exposure times optimized for phase difference detection, while other pixels maintain standard exposure characteristics. This local differentiation resolves the contradiction between systematic arrangement and detection accuracy.
2Measurement precision
If 2×1 on-chip lens structure is adopted for phase difference pixels, then phase difference detection sensitivity is improved, but device complexity increases
Solution Approach 1:
Adjacent phase difference pixels are merged under a single 2×1 on-chip lens structure, allowing them to share the same optical path and exposure timing. This merging improves detection sensitivity while reducing the number of individual lens elements required.
Solution Approach 2:
The 2×1 on-chip lens structure serves multiple phase difference pixels simultaneously, making it a multi-functional optical element that improves sensitivity without proportionally increasing device complexity.
3Measurement precision
If phase difference pixels have adjusted exposure times, then phase difference detection accuracy is improved, but image information capture deteriorates
Solution Approach 1:
The imaging apparatus dynamically switches between different reading modes: a first reading mode that reads only phase difference pixels with adjusted exposure times for accurate phase difference detection, and a second reading mode that reads all pixels with standard exposure times for complete image information capture. This dynamic switching resolves the contradiction between specialized detection and general imaging.
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 configuration improves phase difference detection accuracy and sensitivity by allowing the 2×1 on-chip lens structure, even with differing exposure times, and disperses phase difference pixels across groups, maintaining image information capture.
Implementation Method 1
Each pixel includes a photodiode that photoelectrically converts incident light into electrical charge signals
Data Source
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Figure 3A~3B
AI summary
An imaging apparatus includes a pixel array unit including a plurality of pixel groups, each of the plurality of pixel groups being one of i) a normal pixel group including only normal pixels, or ii) a mixed pixel group including at least one normal pixel and at least one phase difference detection pixel, wherein the pixel array unit comprises at least one normal pixel group and at least one mixed pixel group. For each normal pixel group, the normal pixels receive light transmitted through a same colored color filter. For each mixed pixel group, the at least one phase difference detection pixel shares an on-chip lens with at least one other phase difference detection pixel and receives light transmitted through a same colored color filter as the at least one other phase difference detection pixel.