Image Sensor Asymmetric Pixel Offset to Remove Fixed Pattern Noise
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Solution Overview
Problem
Existing image sensors face characteristic degradation due to fixed pattern noise (FPN), which affects image quality and is challenging to address effectively.
Innovation Solution
The image sensor employs a pixel array with a matrix structure and an image array where pixel positions do not correspond to image dot positions, using a zigzag arrangement of selection lines and symmetrical pixel shapes to prevent FPN expression in the output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixel positions correspond to image dot positions in a direct matrix structure, then device complexity is reduced and manufacturing is simplified, but fixed pattern noise degrades image quality
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the pixel array and image array positions. Specifically, pixels at odd-numbered columns are shifted relative to pixels at even-numbered columns, creating an asymmetric offset pattern. This asymmetric arrangement causes corresponding image dots to be positioned at different rows in the image array, which disrupts the fixed pattern noise while maintaining manageable device complexity through a systematic rather than random offset approach.
2Device complexity
If drivers are positioned uniformly on one side of light receivers, then device complexity is reduced and layout is simplified, but fixed pattern noise affects all pixels uniformly
Solution Approach 1:
The patent implements asymmetry in driver positioning by alternating the side on which drivers are placed relative to light receivers. Drivers for pixels at odd-numbered columns are positioned on one side, while drivers for pixels at even-numbered columns are positioned on the opposite side. This asymmetric driver arrangement, combined with the asymmetric pixel offset, ensures that fixed pattern noise is distributed differently across the image array, preventing uniform noise patterns while maintaining systematic layout control.
3Manufacturing precision
If selection lines are arranged in a regular grid pattern, then manufacturing precision is improved and fabrication is easier, but image quality degrades due to fixed pattern noise
Solution Approach 1:
The patent applies segmentation by dividing the selection lines into two distinct sets: first selection lines coupled to pixels at odd-numbered columns and second selection lines coupled to pixels at even-numbered columns. This segmentation allows each set of selection lines to be independently routed to accommodate the asymmetric pixel offsets, enabling precise manufacturing while preventing fixed pattern noise. The segmented approach transforms a potentially complex unified routing problem into two simpler, independent routing tasks.
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 effectively removes FPN from the image array, improving image quality by aligning drivers and selection lines in a zigzag pattern, reducing design and fabrication complexity, and maintaining image fidelity.
Implementation Method 1
Each of the pixels may include: a light receiver comprising one or more photoelectric conversion elements
Data Source
AI summary
An image sensor may include: a pixel array having a plurality of pixels arranged in a matrix structure; and an image array including a plurality of image dots which are arranged in a matrix structure, and implemented by output signals of the respective pixels. The position of a first pixel in the pixel array may not correspond to the position of an image dot corresponding to the first pixel in the image array, and the position of a second pixel adjacent to the first pixel in the pixel array may correspond to the position of an image dot corresponding to the second pixel in the image array.