X-ray Imaging Panel Reflective Electrode Light Conversion
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Solution Overview
Problem
X-ray imaging systems using indirect conversion schemes face inefficiencies in converting scintillation light into electric charge due to suboptimal utilization of scintillation light by the photoelectric conversion element.
Innovation Solution
Incorporating a reflective layer that overlaps the light-receiving surface of the photoelectric conversion element, which is either a reflective electrode in the same layer as the drain or gate electrode, to enhance the reflection and subsequent conversion of scintillation light into electric charge, combined with a recessed light-receiving surface design to increase the light-receiving area and utilize oxide semiconductor thin film transistors for improved resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reflective layer is added to improve scintillation light conversion, then conversion efficiency improves, but device complexity increases
Solution Approach 1:
The reflective layer is merged with the existing drain electrode or gate electrode layer, making the reflective function an integrated part of the transistor structure rather than a separate component. This combining approach improves conversion efficiency while minimizing additional device complexity.
Solution Approach 2:
The drain electrode or gate electrode is given dual functionality: it serves both as an electrical conductor for the transistor operation and as a reflective layer for scintillation light. This multi-functionality resolves the contradiction by improving conversion efficiency without adding separate reflective components.
2Productivity
If the light-receiving surface area is increased to improve light detection, then conversion efficiency improves, but pixel pitch increases
Solution Approach 1:
The light-receiving surface is designed with a recessed structure that extends in the vertical dimension (depth), allowing increased light-receiving area without proportionally increasing the horizontal pixel pitch. This dimensional approach enables improved light detection sensitivity while maintaining compact pixel dimensions.
Solution Approach 2:
The light-receiving surface features a recessed structure that nests within the pixel boundary, effectively increasing the light-receiving area by utilizing the vertical space within the existing pixel footprint rather than expanding the horizontal pitch.
3Manufacturing precision
If oxide semiconductor thin film transistors are used to improve resolution, then manufacturing precision requirements increase
Solution Approach 1:
The invention utilizes oxide semiconductor material properties (such as high mobility and stability) to achieve high resolution imaging. By selecting and optimizing specific material parameters, the system attains improved resolution while the standard thin film fabrication processes maintain ease of manufacture.
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 significantly improves the conversion efficiency of scintillation light into electric charge, leading to higher resolution images and increased light detection sensitivity, while reducing pixel pitch and storage capacitor area.
Implementation Method 1
a photoelectric conversion element connecting to the thin film transistor and converting the scintillation light that is received to electric charge
Implementation Method 2
a reflective layer that, as seen from a radiation direction of the scintillation light, overlaps an entirety of a region of a light-receiving surface of the photoelectric conversion element where the scintillation light is received
Implementation Method 3
In indirect conversion schemes, a scintillator converts incident X-rays into scintillation light
Data Source
AI summary
An aim of the present invention is to improve the conversion efficiency of scintillation light into electric charge by a photoelectric conversion element in an imaging panel of an X-ray imaging system using an indirection conversion scheme. An imaging panel generates images based on scintillation light acquired from X-rays that have passed through a specimen. The imaging panel includes a substrate, thin film transistor, photoelectric conversion element, and reflective layer. The thin film transistor is formed on the substrate. The photoelectric conversion element is connected to the thin film transistor and converts incident scintillation light into electric charge. The entirety of a region of a light-receiving surface of the photoelectric conversion element where the scintillation light is incident overlaps the reflective layer as seen from the incident direction of the scintillation light. The reflective layer may be the drain electrode. Alternatively, the reflective layer may be a reflective electrode that is formed in the same layer as a gate electrode.