Shared Micro Lens Pixel Layout for PDAF Image Quality
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Solution Overview
Problem
Existing phase detection auto focus (PDAF) systems using image sensors with micro lenses of uniform size degrade image quality and reduce sensitivity due to the inclusion of phase detection pixels, particularly in normal and binning modes.
Innovation Solution
Implementing an image sensor with pixel groups sharing micro lenses of different sizes, where phase detection pixels of different colors share a micro lens, allowing for improved image quality and sensitivity by utilizing both phase detection and image detection pixels effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If phase detection pixels are included in the image sensor for PDAF, then auto focus capability is improved, but image quality and sensitivity are degraded
Solution Approach 1:
The image sensor is divided into distinct pixel groups: some pixels are dedicated to phase detection (with larger micro lenses) and others to image capture (with smaller micro lenses). This segmentation allows each pixel type to be optimized for its specific function, resolving the conflict between AF capability and image quality.
Solution Approach 2:
Different regions of the image sensor have different micro lens sizes tailored to their specific functions. Phase detection pixels have larger micro lenses for enhanced light gathering and phase detection sensitivity, while image capture pixels have smaller micro lenses optimized for image quality. This local differentiation resolves the contradiction by allowing each area to have the quality it needs for its purpose.
2Extent of automation
If phase detection pixels are included in the image sensor for PDAF, then auto focus capability is improved, but sensitivity is reduced
Solution Approach 1:
The sensor is segmented into phase detection pixels with larger micro lenses for high sensitivity AF measurement, and image capture pixels with smaller micro lenses. This segmentation allows the phase detection pixels to achieve high sensitivity for AF without compromising overall sensor performance.
Solution Approach 2:
The micro lens size parameter is changed specifically for phase detection pixels (made larger) to enhance their sensitivity for detecting phase differences, while image capture pixels maintain smaller micro lenses. This parameter differentiation resolves the contradiction by optimizing sensitivity where it is most needed for AF functionality.
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
Enhances image quality and sensitivity by enabling accurate auto focus control using phase difference data from pixels of varying colors, reducing defects in normal mode and improving sensitivity in binning mode compared to traditional PDAF patterns.
Implementation Method 1
a first pixel, among pixels corresponding to the first pixel group, and a second pixel, among pixels corresponding to the second pixel group, may be disposed adjacent to each other and may share a micro lens having a first size
Data Source
AI summary
According to an embodiment of the present disclosure, a pixel array includes a first pixel group corresponding to two or more pixels, each including a color filter corresponding to a first color, and a second pixel group corresponding to two or more pixels, each including a color filter corresponding to a second color, the second color being different from the first color, and a first pixel, among pixels corresponding to the first pixel group, and a second pixel, among pixels corresponding to the second pixel group, are disposed adjacent to each other and share a micro lens having a first size.