Flat Panel Detector Element Layout for Low Leakage and Light Shielding
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Solution Overview
Problem
Current flat panel detectors experience high dark-state leakage current due to suboptimal photoelectric conversion layer structure and divergent X-ray light irradiation, which affects image quality and photoelectric characteristics.
Innovation Solution
The detection element includes a base substrate with a photodiode structure featuring a first electrode, a photoelectric conversion layer, a transparent electrode, and a second electrode, where the orthographic projection of the photoelectric conversion layer falls within the first electrode, and the second electrode partially overlaps with the sidewall of the photoelectric conversion layer, reducing leakage current and providing light shielding to mitigate divergent light irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photoelectric conversion layer structure is used, then the device structure is simple, but dark-state leakage current is high
Solution Approach 1:
The photoelectric conversion layer is segmented into multiple regions with different functions: a first photoelectric conversion region for primary X-ray detection and a second photoelectric conversion region for detecting scattered X-rays. This segmentation allows each region to be optimized independently, reducing overall leakage current while maintaining structural manageability.
Solution Approach 2:
Different regions of the photoelectric conversion layer are assigned different properties: the first region uses a specific thickness and material composition optimized for primary X-rays, while the second region has different characteristics optimized for scattered X-rays. This local differentiation reduces leakage current in each region according to its specific functional requirements.
2Measurement precision
If no light shielding structure is added, then the device structure is simple, but divergent X-ray light causes image quality degradation
Solution Approach 1:
The light shielding structure is designed with asymmetric geometry, including inclined surfaces and non-uniform thickness distribution. This asymmetric design effectively blocks divergent X-ray light paths while minimizing interference with primary X-ray detection, improving image quality without requiring symmetric complex structures.
Solution Approach 2:
The light shielding structure extends into the depth dimension with varying thickness, creating a three-dimensional shielding configuration. This dimensional approach allows the structure to block divergent light from multiple angles while maintaining a compact overall form factor.
3Area of stationary object
If the photoelectric conversion layer projection extends beyond the first electrode, then light collection area is increased, but voltage difference causes increased leakage current
Solution Approach 1:
The photoelectric conversion layer is designed to be completely covered by the first electrode in the orthogonal projection direction, ensuring that the entire photoelectric conversion layer is at the same potential. This equipotential configuration eliminates voltage differences across the photoelectric conversion layer, preventing leakage current while maintaining adequate light collection area through optimized layer thickness.
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 reduces dark-state leakage current and improves photoelectric characteristics by compensating voltage differences and shielding divergent light, enhancing the overall performance of the flat panel detector.
Implementation Method 1
a photoelectric conversion layer on a side of the first electrode away from the base substrate
Data Source
AI summary
A detection element, a manufacturing method thereof and a flat panel detector are disclosed. The detection element includes: a base substrate; a first electrode on the base substrate; a photoelectric conversion layer; a transparent electrode and a second electrode electrically connected with the transparent electrode on a side of the photoelectric conversion layer away from the first electrode. An orthographic projection of the photoelectric conversion layer on the base substrate completely falls within an orthographic projection of the first electrode on the base substrate, in a plane parallel to the base substrate, the transparent electrode is located at a middle portion of the photoelectric conversion, an orthographic projection of the second electrode on the base substrate includes a ring surrounding an orthographic projection of the transparent electrode on the base substrate.