Radiographic Image Detector Radiation Start Detection
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Solution Overview
Problem
Existing radiographic image detectors waste radioactive rays by using them to detect the start of radiation rather than for imaging, as they require external signals or rely on detection elements outside the imaging area or within the imaging area that read out signal charges for detection.
Innovation Solution
A radiographic image detector that detects the start of radiation by monitoring charge leaks from pixels to signal lines while switching elements are OFF, allowing the charge accumulating operation to begin after detection, ensuring that radiated rays are used for imaging without external signals or waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a detection element is disposed outside the imaging area to detect the start of x-ray radiation, then the detector can detect radiation start, but the detection element may be out of the irradiation range and cannot detect x-rays
Solution Approach 1:
The pixels in the imaging area serve dual functions: they act as both imaging elements and radiation detection elements. By monitoring charge leaks from these pixels while switching elements are OFF, the system uses the same imaging pixels for both imaging and radiation start detection, eliminating the need for separate detection elements and ensuring they are always within the irradiation range.
Solution Approach 2:
The imaging pixels themselves perform the radiation start detection function by monitoring their own charge leaks. The system leverages the inherent charge accumulation behavior of the pixels during the OFF state to detect radiation start, allowing the imaging elements to serve their own detection needs without external assistance.
2Reliability
If pixels inside the imaging area are used to detect the start of radiation, then detection is reliable, but signal charges must be read out which wastes x-ray radiation
Solution Approach 1:
The system dynamically controls the switching elements to remain in the OFF state during radiation exposure. By keeping the switching elements OFF, charge leaks accumulate in the pixels without being read out, allowing radiation start detection while preserving the signal charges for subsequent imaging. The readout operation is deferred until after the radiation event is complete.
Solution Approach 2:
The system prepares the pixels by keeping switching elements OFF before radiation starts, allowing charge leaks to accumulate as a detection signal. This preliminary charge accumulation enables radiation start detection without requiring a separate readout operation that would waste imaging opportunities.
3Reliability
If external signals are used to synchronize charge accumulating operation with x-ray radiation, then synchronization is achieved, but incompatible interfaces between different manufacturers' devices occur
Solution Approach 1:
The image detector autonomously detects the start of x-ray radiation by monitoring charge leaks from its own pixels, eliminating the need for external synchronization signals from the x-ray source or control device. This self-detection capability allows the detector to work with any x-ray source regardless of manufacturer or interface standard.
Solution Approach 2:
The system extracts the synchronization function from external sources and relocates it to the image detector itself. By implementing local radiation start detection through charge leak monitoring, the system removes the dependency on external synchronization interfaces and signals.
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
Enables the detection of the start of radiation without external signals, optimizing the use of radioactive rays for imaging by starting the charge accumulating operation after radiation is detected, thus preventing unnecessary exposure and waste.
Implementation Method 1
the radiation detecting device makes a radiation detecting operation for detecting the start of radiation of radioactive rays from a radiation source by monitoring charge leaks from pixels to signal lines of the imaging device while switching elements of the pixels are OFF
Implementation Method 2
pixels having a thin film transistor (TFT) each are arranged in an array for accumulating signal charges in the respective pixels corresponding to the incident amounts of the x-rays
Implementation Method 3
an x-ray source for radiating x-rays
Data Source
AI summary
A flat panel detector (FPD) includes an imaging panel having pixels arranged in a matrix, a gate driver for turning thin film transistors (TFTs) of the pixels ON and OFF, a radiation detecting section for detecting the start of x-ray radiation from the x-ray source, and a controller. The controller controls the gate driver to turn the TFTs ON periodically to reset dark charges of the pixels. Before starting a charge accumulating operation for accumulating signal charges for imaging, the controller controls the gate driver to turn the TFTs OFF so that the radiation detecting section may detect the start of x-ray radiation on the basis of charge leaks from the pixels. When the start of x-ray radiation is detected, the controller starts the charge accumulating operation while keeping the TFTs in the OFF condition. Thereafter, the TFTs are turned ON to read out the accumulated signal charges.