X-ray Flat Panel Detector Electric Field Charge Collection
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Solution Overview
Problem
The existing X-ray flat panel detectors suffer from reduced quantum detection efficiency and sensitivity due to limitations in the doping concentration of boron and phosphorus atoms in photodiodes and defects in amorphous silicon materials, leading to inefficient charge collection and recombination.
Innovation Solution
The X-ray flat panel detector incorporates an electric field application portion with a positive and negative electrode layer configuration, where the photodiodes are arranged such that the electric field direction aligns with the movement of negative charges, accelerating the movement of holes and electrons and improving signal arrival at the pixel electrode, thereby enhancing detection efficiency and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the doping concentration of boron and phosphorus atoms is increased to improve charge collection speed, then the collection speed improves, but the material properties deteriorate when saturation concentration is exceeded
Solution Approach 1:
The patent changes the physical parameter of the photodiode by introducing an external electric field through electrode layers, altering the charge collection mechanism from diffusion-driven to field-driven drift movement, thereby improving collection speed without increasing doping concentration
Solution Approach 2:
The patent introduces electrode layers as intermediary components that generate an external electric field, which acts as a mediator to accelerate charge carrier movement through the photodiode, resolving the contradiction between collection speed and material integrity
2Productivity
If the doping concentration is increased to improve charge collection efficiency, then collection efficiency improves, but detection efficiency and sensitivity are reduced due to charge capture by defects
Solution Approach 1:
The patent changes the electric field parameter by applying an external field through electrodes, which accelerates charge drift velocity and improves collection efficiency without increasing doping concentration, thereby avoiding the formation of recombination centers that would reduce detection sensitivity
Solution Approach 2:
The patent replaces the chemical/diffusion-based charge transport mechanism with an electric field-driven drift mechanism, substituting the reliance on doping concentration with an externally controllable electric field to improve collection efficiency while maintaining material quality
3Speed
If a stronger build-in electric field is created to speed up charge collection, then collection speed improves, but the doping concentration must exceed saturation concentration which deteriorates material properties
Solution Approach 1:
The patent introduces electrode layers as intermediary components that generate the required strong electric field externally, eliminating the need to increase doping concentration beyond saturation levels, thus maintaining ease of manufacture while achieving fast charge collection
Solution Approach 2:
The patent changes the source of the electric field from internal (doping-based build-in field) to external (electrode-based applied field), allowing strong fields to be created without exceeding doping saturation concentrations, thereby maintaining material fabrication feasibility
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 results in improved quantum detection efficiency and sensitivity by ensuring that electrical signals are promptly collected and processed, reducing electron-hole recombination and enhancing the overall performance of the X-ray detector.
Implementation Method 1
an electric field application portion configured to generate an electric field, wherein the photodiodes are arranged in the electric field, and a moving direction of negative charges when visible light rays are converted to electrical signals by the photodiodes is substantially same as a direction of the electric field
Implementation Method 2
the electrical signal converted by the photodiode... when visible light rays are converted to electrical signals by the photodiodes
Data Source
AI summary
The present disclosure provides an X-ray flat panel detector including: a base substrate; thin film transistors (TFTs), a pixel electrode layer, photodiodes, a transparent electrode layer, and an X-ray conversion layer which are arranged on the base substrate; and an electric field application portion configured to generate an electric field, wherein the photodiodes are arranged in the electric field, and a moving direction of negative charges when visible light rays are converted to electrical signals by the photodiodes is substantially same as a direction of the electric field. In this detector, it is applied a direction of the electric field which is substantially same as the moving direction of negative charges in the photodiode, so that movement of holes and electrons of the photodiode may be accelerated under an influence of the electric field, and thus the electrical signal may promptly arrive at the pixel electrode. As a result, it is improved the quantum detection efficiency and the sensitivity of the X-ray flat panel detector.