Radiation Detector Conductive Layer Charge Dispersion
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Solution Overview
Problem
Existing radiation detectors face challenges in suppressing image quality deterioration due to changes in electrostatic capacitance, which cannot be effectively addressed by existing techniques without increasing the size of the detector.
Innovation Solution
A radiation detector design that includes a conductive layer on the substrate's surface near the peripheral edge of the bias electrode, which disperses charges generated by the electric field, thereby stabilizing electrostatic capacitance and preventing image quality degradation while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If guard electrodes are disposed between signal lines and semiconductor layer in peripheral portion, then noise generated in signal line by capacitor coupling is prevented, but device complexity increases
Solution Approach 1:
The patent introduces a guard electrode as an intermediary element disposed between the signal line and the semiconductor layer in the peripheral portion. This guard electrode acts as a mediator that prevents direct capacitor coupling between the signal line and semiconductor layer, thereby eliminating noise while adding only minimal structural complexity.
2Reliability
If dummy electrodes are disposed at peripheral portions to prevent dielectric breakdown, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by disposing dummy electrodes at the peripheral portions of the semiconductor layer before high voltage is applied to the collecting electrodes. These dummy electrodes pre-establish equipotential regions that prevent dielectric breakdown from occurring, thereby improving reliability without significantly increasing device complexity.
3Productivity
If collecting electrodes are disposed in periphery opposing bias electrode, then charge collection is enabled, but electrostatic capacitance changes affecting image quality occur
Solution Approach 1:
The patent applies local quality by making the peripheral portion of the semiconductor layer have different electrical characteristics from the central portion. Specifically, the peripheral portion is designed with different conductivity or thickness to reduce electrostatic capacitance changes in this specific region, thereby maintaining image quality while preserving charge collection function.
Solution Approach 2:
The patent changes physical parameters of the semiconductor layer in the peripheral portion, such as conductivity, thickness, or doping concentration, to reduce electrostatic capacitance variations. By adjusting these parameters locally in the peripheral region, the patent prevents image quality deterioration caused by capacitance changes while maintaining effective charge collection.
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
The solution effectively suppresses image quality deterioration and prevents size increase by uniformly dispersing charges, ensuring stable image capture without external electrode placement, thus enhancing the detector's performance and compactness.
Implementation Method 1
a semiconductor layer, formed on the plurality of collecting electrodes, that generates charges when radiation is irradiated
Implementation Method 2
a bias electrode, formed on the semiconductor layer, that applies a bias voltage for generating an electric field for moving charges having a polarity of a detection target among the generated charges, to the collecting electrodes
Implementation Method 3
An electrostatic capacitance (so-called, parasitic capacitance) is generated in an insulating substrate by an electric field generated by applying the bias voltage to the bias electrode, and thereby charges are generated
Data Source
AI summary
The present invention provides a radiation detector that can suppress a deterioration of image quality of a radiation image while suppressing the size of the radiation detector. Namely, a conductive layer configured by a conductive member is disposed at a portion that corresponds to at least the back side of the peripheral edge portion of a bias electrode, on the surface of an insulating substrate.