Image Sensor Pixel Layout With Diagonal Binning for Balanced Resolution
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Solution Overview
Problem
Image sensors with existing pixel arrangements produce final color images with imbalanced resolution in horizontal, vertical, diagonal, and counter diagonal directions, leading to suboptimal image quality.
Innovation Solution
Implement a 4×4 4-cell pixel array with diagonal and counter diagonal binned photodiodes (PDs) to achieve balanced resolution in all directions, using binning techniques to combine pixel values and remosaicing algorithms for interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an image sensor comprises only vertical PDs or horizontal PDs, then the structure is simple, but the final color image will have imbalance between horizontal and vertical resolutions
Solution Approach 1:
The patent applies asymmetry by introducing diagonal and counter-diagonal photodiode arrangements in addition to vertical and horizontal ones. This creates a symmetric overall structure that balances resolution in all directions (horizontal, vertical, diagonal, and counter-diagonal), resolving the resolution imbalance problem while maintaining reasonable structural complexity through systematic symmetry rather than random asymmetry.
Solution Approach 2:
The patent transitions from one-dimensional (vertical or horizontal) photodiode arrangements to two-dimensional arrangements that include diagonal and counter-diagonal orientations. This dimensional expansion enables balanced resolution in multiple directions simultaneously, solving the resolution balance issue without requiring overly complex multi-layer structures.
2Reliability
If four pixels are binned together, then the signal-to-noise ratio is enhanced in low light environment, but the resolution in the binned direction is reduced
Solution Approach 1:
The patent segments the binning operation into multiple independent directional components (vertical, horizontal, diagonal, counter-diagonal). Instead of uniform binning that sacrifices resolution in one direction, each directional pair can be binned independently, allowing the system to enhance signal-to-noise ratio in specific directions while preserving resolution in other directions, thus resolving the trade-off between SNR and spatial resolution.
Solution Approach 2:
The patent enables dynamic selection of binning modes and directional combinations based on scene requirements. The system can adaptively choose to bin vertically, horizontally, diagonally, or in various combinations, allowing optimization between signal-to-noise ratio and spatial resolution depending on lighting conditions and imaging requirements, thereby resolving the static trade-off.
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
The solution results in a final color image with balanced resolution across all directions, enhancing image quality and sampling rates, particularly in low light conditions.
Implementation Method 1
A pixel may include two vertical photodiodes (PDs), i.e., left PD and right PD, under a microlens
Data Source
AI summary
An image sensor comprises a 4-cell DPD pixel array having a first group of pixels, a second group of pixels, a third group of pixels, and a fourth group of pixels. The first group of pixels comprises a first pixel, a second pixel, a third pixel, and a fourth pixel. The first pixel comprises a first photodiode, a second photodiode, a third photodiode, and a fourth photodiode. The four photodiodes are covered by a microlens. The first photodiode is diagonally binned with the fourth photodiode, and the second photodiode is counter-diagonally-binned with the third photodiode.