Image Sensor Auto Focus Pixel Asymmetric Light Blocking
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Solution Overview
Problem
Existing image sensors face challenges in improving auto focus (AF) performance without compromising the performance of normal pixels, as the positioning of light blocking members and lenses can either optimize light reception for normal pixels or disrupt AF functionality.
Innovation Solution
The image sensor incorporates a pixel array with AF pixels featuring two or more sub-pixels, light blocking members, and lenses, where the light blocking members are strategically shifted to optimize both normal pixel light reception and AF performance by ensuring proper light division and phase detection between sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light blocking member is positioned at the intermediate point of sub-pixels for optimal AF phase detection, then AF performance is improved, but light reception performance of normal pixels deteriorates
Solution Approach 1:
The light blocking member is deliberately positioned asymmetrically relative to the sub-pixels, specifically shifted from the intermediate point toward one sub-pixel. This asymmetric positioning creates different light path blockages for different sub-pixels, enabling phase detection for AF while maintaining sufficient light reception for normal pixel operation. The asymmetric design allows the system to achieve both AF functionality and acceptable image quality without requiring symmetric intermediate positioning.
2Use of energy by moving object
If the lens is positioned to optimize light reception for normal pixels, then normal pixel performance is improved, but AF functionality deteriorates
Solution Approach 1:
The light blocking member acts as an intermediary element between the lens and the sub-pixels. It mediates the light paths by selectively blocking light from reaching specific sub-pixels, thereby enabling phase detection for AF while allowing the lens to maintain its optimal position for light reception. This intermediary structure allows the lens to serve dual purposes: optimizing normal pixel light reception while enabling AF functionality through the light blocking member's strategic positioning.
3Measurement precision
If multiple light blocking members are added to improve AF performance, then AF measurement precision is improved, but device complexity increases
Solution Approach 1:
The pixel structure is segmented into multiple sub-pixels (first sub-pixel, second sub-pixel, and optionally third sub-pixel), with light blocking members positioned between them. This segmentation allows different regions of the pixel to serve different functions: some sub-pixels are optimized for AF phase detection while others maintain light reception capabilities. The segmented approach enables improved AF measurement precision through multiple light path comparisons without requiring a completely complex redesign of the entire pixel structure.
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 enhances AF performance while maintaining the image capturing quality of normal pixels by optimizing light distribution and phase detection, preventing deterioration in either aspect.
Implementation Method 1
a light blocking member provided between the two sub-pixels
Implementation Method 2
a lens corresponding to the two sub-pixels
Implementation Method 3
The image sensor includes a photoelectric transformation element and a plurality of pixels
Data Source
AI summary
Provided is an image sensor including a pixel array including a plurality of auto focus (AF) pixels and a plurality of normal pixels, wherein each of the plurality of AF pixels comprises two sub-pixels, a light blocking member provided between the two sub-pixels, and a lens corresponding to the two sub-pixels, and wherein the light blocking member is shifted from an intermediate point of the two sub-pixels.