Radiation Image Detector Power Management via Bias Line Current
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Solution Overview
Problem
Conventional radiation image detecting devices face power consumption issues due to unnecessary readout operations before detecting the start of X-ray irradiation, leading to increased battery exchange frequency in portable devices, and require electrical connection for synchronization, which is not compatible with self-detection configurations.
Innovation Solution
The device detects the start of radiation irradiation based on leak charge from pixels, turning on all switching elements until irradiation is detected, then shifting to charge accumulation, and only supplying power to the signal processing circuit and communication section after detection, allowing for wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device continuously performs readout operations to detect the start of X-ray irradiation, then the detection reliability is improved, but the power consumption increases
Solution Approach 1:
The device performs readout operations periodically at predetermined intervals rather than continuously, allowing the imaging device to enter a low-power state between readings. This periodic detection maintains the ability to reliably detect X-ray irradiation start while significantly reducing overall power consumption compared to continuous operation.
Solution Approach 2:
The imaging device autonomously detects the start of X-ray irradiation by monitoring its own bias line current without requiring external synchronization signals. This self-detection capability eliminates the need for continuous communication with the X-ray generation device, reducing power consumption while maintaining detection reliability.
2Measurement precision
If the device uses electrical connection for synchronization between X-ray generation and imaging devices, then the synchronization precision is improved, but the device complexity and portability are worsened
Solution Approach 1:
The imaging device independently detects the start of X-ray irradiation by monitoring changes in bias line current that occur when X-rays are generated. This self-detection method eliminates the need for external synchronization signals and electrical connections between devices, simplifying the system while maintaining precise timing synchronization.
Solution Approach 2:
The patent replaces the mechanical/electrical synchronization system (physical cable connections and synchronization signals) with an electromagnetic detection system that monitors bias line current changes. This substitution eliminates physical connections while maintaining the ability to precisely detect irradiation start timing.
3Speed
If the signal processing circuit operates continuously to process image data, then the processing speed is improved, but the power consumption increases
Solution Approach 1:
The signal processing circuit is activated only periodically when needed for data processing, rather than operating continuously. The circuit remains in a low-power state between processing tasks, reducing overall power consumption while maintaining high processing speed when actually operating.
Solution Approach 2:
The signal processing circuit dynamically transitions between active and low-power states based on operational needs. The circuit is activated when image data processing is required and enters a low-power state when no processing is needed, optimizing the balance between processing speed and power consumption.
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 achieves power saving by minimizing unnecessary operations and eliminating the need for electrical connection between devices, enhancing portability and reducing battery exchange frequency.
Implementation Method 1
Pixels that accumulate signal charge corresponding to an amount of incident X-rays are arranged in a matrix in the FPD
Implementation Method 2
the start of the radiation irradiation is detected based on leak charge leaking from the pixels
Data Source
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AI summary
An FPD (36) is provided with an ammeter (56) for measuring current on a wired connection (45) of a bias line (44) that applies a bias voltage to pixels (37). A control circuit (41) compares the measured value of the ammeter (56) and a threshold value. When the measured value of the ammeter (56) is equal to or larger than the threshold value, the control circuit (41) judges that an emission of X-rays from an X-ray source (13) is started. Until before the start of the X-ray irradiation is detected, the control circuit (41) stops supplying electric power to a signal processing circuit (40), and turns on all TFTs (43) . Once the start of the X-ray irradiation is detected, the control circuit (41) turns off all the TFTs (43), and makes the FPD (36) shift to a charge accumulation operation. Thereafter, the control circuit (41) turns on a processing power source (52) to start supplying the electric power to the signal processing circuit (40).