Image Detector With Gradient Openings to Reduce Pixel Crosstalk
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Solution Overview
Problem
Existing image detectors suffer from lateral diffusion of light, leading to blurring and reduced spatial resolution due to light emitted in large angles, which causes crosstalk between pixels and decreases image quality.
Innovation Solution
The image detector incorporates a pixel array with photosensitive pixels featuring a photoelectric conversion layer and a light shielding layer with varying opening sizes, where openings near the pixel edges are smaller to block large-angle light, while those near the center are larger to allow more light entry, thereby reducing crosstalk and improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light shielding layer with uniform opening size is used, then the structure is simple and easy to manufacture, but large-angle light diffusion causes crosstalk and blurring between pixels
Solution Approach 1:
The light shielding layer employs openings of different sizes at different locations: larger openings at the center of each pixel to maximize light collection, and progressively smaller openings toward the pixel edges to block crosstalk from adjacent pixels. This local variation in opening quality optimizes both light transmission and spatial resolution without requiring complete structural redesign.
Solution Approach 2:
The light shielding layer is segmented into multiple regions with different opening characteristics - central regions with larger openings for primary light collection and peripheral regions with smaller openings for crosstalk suppression. This segmentation allows each region to be optimized for its specific function while maintaining overall manufacturing simplicity through a systematic pattern.
2Illumination intensity
If openings are made larger to allow more light entry, then signal-to-noise ratio improves, but lateral diffusion of light increases causing image blurring
Solution Approach 1:
The opening size is locally optimized based on position: central openings are larger to maximize photon collection and improve signal-to-noise ratio, while peripheral openings are smaller to restrict the angular acceptance and prevent lateral light diffusion. This creates a gradient that balances signal intensity and spatial fidelity.
Solution Approach 2:
The opening diameter parameter is systematically varied across the pixel array - increasing from edges toward the center. This parameter change allows the system to adapt locally: larger openings where signal strength is prioritized (center) and smaller openings where spatial precision is critical (edges), resolving the contradiction between signal-to-noise ratio and spatial resolution.
3Measurement precision
If openings are made smaller to block large-angle light, then crosstalk is reduced, but less light reaches the photoelectric conversion layer
Solution Approach 1:
Different regions of the light shielding layer have different opening sizes matched to their functional requirements. Peripheral regions use smaller openings to prioritize crosstalk rejection, while central regions use larger openings to prioritize light transmission. This local differentiation ensures that no single region is over-constrained.
Solution Approach 2:
The light shielding layer is divided into functional zones - a central zone with larger openings for high signal-to-noise ratio requirements and peripheral zones with smaller openings for high spatial resolution requirements. This segmentation allows the system to accumulate sufficient light in the center while maintaining sharp boundaries at the edges.
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 design effectively blocks large-angle light diffusion, enhancing image resolution and reducing blurring, thus improving the overall image quality by minimizing crosstalk and increasing the signal-to-noise ratio.
Implementation Method 1
Each of the plurality of photosensitive pixels includes a photoelectric conversion layer configured to convert incident light into signal charges
Data Source
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AI summary
An image detector comprises a plurality of photosensitive pixels that each pixel includes a photoelectric conversion layer and a light shielding layer overlapped each other. A plurality of openings are made on the light shielding layer in a manner that its light passing area is substantially proportional to a distance from the opening to a border of the pixel.