Erasing Light Control for Amorphous Selenium Radiation Detectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radiation image capture devices face issues with lag images and non-uniformities due to the slow transportation of charges in amorphous selenium photoconductor layers, leading to offset variations and image quality degradation, especially in tomosynthesis imaging where rapid switching of erasing light causes instability and in 2D imaging where longer irradiation durations exacerbate non-uniformities.
Innovation Solution
A radiation image capture device with a controller that manages the erasing light source by keeping it deactivated during short irradiation durations in tomosynthesis imaging and activated during longer durations in 2D imaging, ensuring stable charge states and minimizing lag image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the erasing light is repeatedly activated and deactivated at short cycles during tomosynthesis imaging, then lag images are erased, but offset variation occurs in image signals causing instability
Solution Approach 1:
The erasing light is activated in advance before the start of tomosynthesis imaging and remains on throughout the entire imaging sequence. This preliminary and continuous activation prevents lag image accumulation without causing the offset variation that results from repeated on-off cycling, thereby maintaining image signal stability while effectively erasing lag images.
2Reliability
If the erasing light is activated during 2D imaging with long irradiation duration, then lag images are erased, but non-uniformities arise in radiation images
Solution Approach 1:
The erasing light is activated in periodic intervals during 2D imaging rather than continuously. Specifically, it is activated before radiation irradiation to erase lag images, then deactivated during the irradiation period to prevent non-uniformities, and reactivated after irradiation completes. This periodic activation pattern balances lag image erasure with maintenance of image uniformity.
3Measurement precision
If amorphous selenium photoconductor layer is used, then high sharpness and high sensitivity are achieved, but slow charge transportation causes lag images
Solution Approach 1:
The erasing light acts as an intermediary mechanism to address the slow charge transportation in amorphous selenium photoconductor layers. By illuminating the photoconductor layer with erasing light, photoelectric charges are generated that promote the disappearance of residual charges, thereby eliminating lag images while preserving the high sharpness and sensitivity benefits of the amorphous selenium material.
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 approach enhances image quality by preventing offset variations and non-uniformities, achieving better image quality in both short and long irradiation duration imaging modes by maintaining the erasing light source's state accordingly.
Implementation Method 1
light (referred to below as erasing light) is illuminated toward the radiation detector to generate photoelectric charges inside the photoconductor layer, promoting the disappearance of residual charge remaining in the photoconductor layer
Implementation Method 2
Direct conversion method type radiation detectors convert X-ray data directly into electrical signals in a photoconductor layer employing amorphous selenium (a-Se)
Data Source
AI summary
A radiation image capture device is provided that are capable of obtaining radiation images with better image quality than hitherto in both an imaging mode in which a radiation irradiation duration is comparatively short and radiation images are successively captured, and in an imaging mode in which the radiation irradiation duration is comparatively long. An erasing light source is deactivated throughout an imaging period in a first imaging mode in which a radiation detector generates image data of a radiation image based on radiation irradiated from a radiation source over a first irradiation duration. The erasing light source is activated over an imaging period in a second imaging mode in which the radiation detector generates image data of plural radiation images based on successively irradiated radiation from the radiation source over a second irradiation duration shorter than the first irradiation duration.