3D Image Sensor Pixel Merging for Low Light Sensitivity
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Solution Overview
Problem
Three-dimensional image sensors face challenges in achieving accurate distance measurement due to the lower light sensitivity of distance measuring pixels, which results in reduced signal-to-noise ratio and degraded resolution, especially in low illuminance conditions.
Innovation Solution
The implementation of a 3D image sensor that selectively uses multiple distance measuring pixels as one unit based on object illuminance, with adjacent pixels jointly outputting a distance measurement signal, and includes switching devices to manage signal output based on illuminance levels, allowing for either combined or individual pixel operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the area of distance measuring pixel is increased to compensate for lower sensitivity, then light sensitivity is improved, but resolution is degraded
Solution Approach 1:
Multiple distance measuring pixels (e.g., four pixels) are merged to function as a single distance measuring unit. This combining approach increases the effective light-sensitive area for distance measurement, improving sensitivity without requiring individual pixels to be larger and thus preserving resolution.
2Manufacturing precision
If the size of distance measuring pixel is reduced, then resolution is improved, but signal-to-noise ratio is reduced
Solution Approach 1:
Multiple small-distance measuring pixels are combined to form a functional unit with larger effective area. This merging maintains the high resolution benefits of small pixels while achieving the signal-to-noise ratio improvement that would otherwise require larger individual pixels.
3Manufacturing precision
If multiple distance measuring pixels are used individually, then resolution is maintained, but sensitivity in low illuminance is insufficient
Solution Approach 1:
The system dynamically switches between individual pixel operation and combined pixel operation based on illuminance conditions. In high illuminance, individual pixels maintain resolution; in low illuminance, multiple pixels combine to enhance sensitivity, creating an adaptive solution.
4Quantity of substance
If distance measuring pixels are arranged with adjacent corners touching, then pixel density is improved, but signal integration complexity increases
Solution Approach 1:
The pixel array is segmented into groups where adjacent distance measuring pixels form discrete functional units. This segmentation approach maintains high pixel density while organizing the structure to simplify signal integration within each group.
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 approach enhances the sensitivity and accuracy of distance measurements, particularly in low illuminance conditions, by optimizing pixel operation based on illuminance levels, thereby improving the overall performance of the 3D image sensor.
Implementation Method 1
a photodiode PD that receives the incident light
Data Source
AI summary
A three-dimensional (3D) image sensor includes a plurality of color pixels, and a plurality of distance measuring pixels. Where the plurality of color pixels and the plurality of distance measuring pixels are arranged in an array, and a group of distance measuring pixels, from among the plurality of distance measuring pixels, are disposed so that a corner of each distance measuring pixel in the group of distance-measuring pixels is adjacent to a corner of an adjacent distance-measuring pixel in the group of distance-measuring pixels. The group of distance measuring pixels is capable of jointly outputting one distance measurement signal.