Image Sensor Pixel Layout for Faster Phase Difference Autofocus
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Solution Overview
Problem
Existing solid-state imaging apparatuses face challenges in providing suitable phase difference pixels for improved auto-focus speed, particularly with systematically arranged shared pixels where neighboring pixels of the same colors share pixel circuits.
Innovation Solution
The imaging apparatus includes a pixel array unit with mixed pixel groups that contain phase difference detection pixels sharing an on-chip lens and color filter, allowing for adjusted exposure times and improved phase difference detection accuracy, while normal pixel groups receive light through the same colored color filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase difference pixels are added to improve auto-focus speed, then auto-focus speed is improved, but device complexity increases
Solution Approach 1:
The patent combines phase difference detection pixels with normal imaging pixels in mixed pixel groups, where phase difference pixels share on-chip lenses and color filters with normal pixels. This merging approach enables phase difference detection functionality without adding separate dedicated hardware systems, thus improving auto-focus speed while controlling device complexity.
Solution Approach 2:
The patent makes pixels serve multiple functions by creating mixed pixel groups where the same pixel structure supports both normal imaging and phase difference detection. The on-chip lenses and color filters are shared between normal pixels and phase difference pixels, allowing universal use of these components for different functions.
2Device complexity
If phase difference pixels share on-chip lenses to reduce device complexity, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent applies local quality by providing dedicated on-chip lenses specifically for phase difference pixels within mixed pixel groups, while normal pixels share lenses. This ensures that phase difference detection, which requires high precision, receives dedicated optical resources, while normal imaging can share resources. The local optimization maintains measurement precision for phase difference detection while still reducing overall device complexity through sharing.
3Reliability
If mixed pixel groups are arranged at predetermined intervals to maintain normal pixel groups, then normal pixel functionality is preserved, but device complexity increases
Solution Approach 1:
The patent segments the pixel array into distinct normal pixel groups and mixed pixel groups arranged at predetermined intervals. This segmentation allows normal pixel groups to maintain their dedicated functionality for high-quality imaging, while mixed pixel groups provide phase difference detection. The periodic arrangement ensures that normal pixel functionality is preserved in sufficient quantity and distribution, while adding phase difference capability without requiring complete restructuring of the entire pixel 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 configuration enables more suitable phase difference pixels, enhancing auto-focus speed and accuracy by optimizing the arrangement and exposure times of phase difference detection pixels within the pixel array.
Implementation Method 1
phase difference detection pixels sharing 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
Data Source
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.