Wireless Imager Low Power Standby via Pixel Biasing
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Solution Overview
Problem
Wireless radiographic imagers face challenges in conserving battery power while maintaining high-quality image generation, particularly in overcoming cold-start artifacts and minimizing power consumption during idle periods.
Innovation Solution
A wireless flat panel detector system utilizing a combination of NIP photodiodes and TFT switches, where the bias supply maintains a reverse bias voltage to charge storage devices, allowing for low power consumption and stable pixel charge traps, even during idle periods, and adjusts power states dynamically between active and low power modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the wireless flat panel detector is completely powered off during idle periods to conserve battery power, then power consumption is minimized, but cold-start artifacts occur in the first image after power-on
Solution Approach 1:
The patent applies preliminary action by maintaining a reverse bias voltage on the photodiodes during idle periods before actual imaging begins. This preliminary biasing keeps the charge storage devices in a stable state, preventing cold-start artifacts when imaging resumes. The system transitions from complete power-off to a low-power standby state where only the bias supply remains active, performing the necessary preparation in advance to ensure image quality while minimizing power consumption.
2Reliability
If the reverse bias voltage is maintained on photodiodes during idle periods to prevent cold-start artifacts, then image quality is maintained, but power consumption increases
Solution Approach 1:
The patent applies local quality by selectively maintaining power only to the bias supply circuit that provides reverse bias voltage to the photodiodes, while completely powering off other subsystems during idle periods. This includes shutting down the readout electronics, data processing units, wireless communication modules, and display systems. By applying different power states to different parts of the system - keeping only the essential bias voltage active - the patent achieves local optimization of the power-quality tradeoff.
3Reliability
If all panel electronics are kept on to maintain stable pixel charge traps, then cold-start artifacts are prevented, but battery life is significantly reduced
Solution Approach 1:
The patent applies the taking out principle by extracting and isolating the essential function needed for preventing cold-start artifacts - the reverse bias voltage on photodiodes - from the complete panel electronics system. By separating this critical function from the rest of the electronics and maintaining only this minimal subset during idle periods, the patent dramatically reduces power consumption while preserving the essential pixel stability function. All non-essential electronics are removed from the active state.
4Adaptability or versatility
If the wireless imager uses battery power instead of mains power to improve portability, then mobility is enhanced, but power management complexity and consumption increase
Solution Approach 1:
The patent applies dynamics by implementing dynamic power management that adapts the system's power state based on operational requirements. The system dynamically transitions between different power modes: full power during active imaging, and a specialized low-power standby mode during idle periods that maintains only the photodiode bias voltage. This dynamic adaptation allows the battery-powered system to optimize its power consumption profile, extending battery life and enhancing the practical portability of the wireless imager.
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 minimizes power consumption, prevents cold-start artifacts, and extends battery life by keeping the pixels biased, ensuring high-quality images are generated immediately after a cold start while conserving battery power.
Implementation Method 1
each charge storage device consists of a photodiode for storing charge
Implementation Method 2
the bias supply provides a reverse bias voltage to the charge storage devices in order to maintain a stable voltage level
Data Source
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AI summary
This invention describes a novel solution to conserve battery and to overcome cold-start artifacts by maintaining the pixel charge traps at a stable value at all times. The design of NIP photodiode and TFT combination requires very low current (in order of hundreds of μΑ) to stay biased at all times. This allows the pixel charge traps to be easily maintained at a stable value with low power consumption. Power consumption is kept at a minimum by keeping all panel electronics off and only the pixels biased. In addition, keeping the pixels biased helps to overcome the cold-start artifact in the very first image.