Radiographic Detector Power Control Circuit for Rapid Imaging
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Solution Overview
Problem
Digital radiography detectors with amorphous or poly-crystalline photosensors face challenges in transitioning from a zero-power state to a stable state ready for exposure, leading to delays and potential image quality issues due to the long time required for trap states to equilibrate, which can result in offset between images and complex calibration processes.
Innovation Solution
A digital radiographic area detector with a power control circuit that maintains a prescribed voltage across photosensors, allowing for a rapid transition from a low-power deep-sleep mode to a state capable of low-noise image acquisition, using a bias control circuit and photosensor power control circuitry to minimize power consumption and reduce battery drain between radiographic studies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If photosensors are completely powered down between exposures, then power consumption is reduced, but transition to stable imaging state takes 1-60 seconds due to trap state equilibration
Solution Approach 1:
The patent applies preliminary action by maintaining photosensors in a deep-sleep mode with prescribed bias voltage applied before actual imaging operations. This preliminary biasing prepares the trap states in advance, enabling rapid transition to stable imaging state when power is fully activated, thus resolving the contradiction between power savings and power-up time delay
Solution Approach 2:
The patent implements dynamics by creating multiple power modes (deep-sleep mode with minimal bias and full-power imaging mode). The system dynamically transitions between these modes based on operational needs, allowing rapid switching from low-power state to imaging-ready state without the 1-60 second delay associated with complete power-down, thereby balancing power consumption with response time
2Speed
If photosensors are kept in continuously powered state, then rapid transition to imaging state is achieved, but power consumption increases and causes battery drain
Solution Approach 1:
The patent applies periodic action by implementing cyclic transitions between deep-sleep mode and full-power imaging mode. Photosensors are periodically re-bias ed before each imaging sequence rather than maintaining continuous full power. This periodic re-biasing maintains rapid transition capability while significantly reducing overall power consumption and preventing battery drain during extended idle periods
3Use of energy by moving object
If photosensors are completely powered down, then power consumption is minimized, but offset between images and complex calibration are required
Solution Approach 1:
The patent applies preliminary action by maintaining a prescribed bias voltage across photosensors during deep-sleep mode. This preliminary biasing prevents complete discharge of trap states, thereby eliminating the need for complex calibration procedures and offset corrections that would otherwise be required after complete power-down. Image quality is maintained while still achieving significant power savings compared to continuous full-power operation
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 rapid transition to a stable imaging state with reduced power consumption, minimizing delays and improving image quality by maintaining photosensors in a continuously powered state with a prescribed bias voltage, thus reducing transient charge and dark current, and simplifying calibration processes.
Implementation Method 1
A digital radiographic area detector with a power control circuit that maintains a prescribed voltage across photosensors
Implementation Method 2
Each pixel generally includes a photosensor and a switching element that can be arranged in a co-planar or a vertically integrated manner
Data Source
AI summary
Embodiments of methods/apparatus can transition a DR detector imaging array to low power photosensor mode where a first voltage is applied across the photosensors. Embodiments of methods/apparatus can provide an area radiographic imaging array including a plurality of pixels arranged in a matrix at the imaging array where each pixel can include at least one electrically chargeable photosensor and at least one transistor, row address circuits, signal sensing circuits, and photosensor power control circuitry to maintain a first voltage across photosensors of the portion of the imaging array when the detector is between imaging operations. In one embodiment, photosensor power control circuitry can maintain the first voltage across the photosensors when a power consumption of the signal sensing circuits is less than 1% of the power consumption of the signal sensing circuits during readout of a signal from the portion of the imaging array.