X-ray Detector Capacitance Reduction via Series Storage
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Solution Overview
Problem
Current X-ray detection systems face challenges in reducing pixel RC delay, which leads to longer data read-out times due to high capacitance in photo diodes, affecting the efficiency of X-ray image acquisition, especially in applications requiring rapid image capture like motion pictures.
Innovation Solution
The proposed X-ray detecting apparatus incorporates a storage capacitor connected in series with the photo diode, reducing total capacitance and pixel RC delay by integrating a switching transistor and a data line configuration that includes a gate electrode, a first electrode, and a second electrode, with a bias voltage applied to the anode electrode, thereby shortening data read-out time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photo diode with high capacitance is used in the X-ray detection system, then the photo diode can detect X-ray signals effectively, but the pixel RC delay increases leading to longer data read-out times
Solution Approach 1:
The patent extracts the storage function from the photo diode by introducing a separate storage capacitor connected in series with the photo diode. This separation allows the photo diode to maintain its high capacitance for effective X-ray detection while the series combination reduces the total capacitance affecting the pixel RC delay, thereby reducing data read-out time without compromising detection capability
Solution Approach 2:
The storage capacitor acts as an intermediary element between the photo diode and the readout circuit. It mediates the conflict by providing a path that allows the photo diode to operate with high capacitance for signal detection while the series connection configuration reduces the effective capacitance impacting the RC time constant, thus reducing pixel RC delay and read-out time
2Loss of time
If the capacitance of the photo diode is reduced to shorten pixel RC delay, then data read-out time decreases, but the X-ray detection sensitivity is compromised
Solution Approach 1:
The storage function is extracted from the photo diode and placed in a separate storage capacitor connected in series. This allows the photo diode to maintain high capacitance for sensitivity while the series combination reduces the total capacitance affecting RC delay, solving the contradiction between detection sensitivity and read-out speed
Solution Approach 2:
The detection system is segmented into distinct functional components: the photo diode for signal generation, the storage capacitor for charge storage and capacitance management, and the readout circuit. This segmentation allows each component to be optimized independently - the photo diode for sensitivity and the series combination for reduced RC delay
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 configuration reduces the pixel RC delay, resulting in faster read-out times and improved efficiency for X-ray image acquisition, particularly beneficial for applications requiring rapid image capture.
Implementation Method 1
An X-ray detection system is a system that transmits X-rays through an object, e.g., human body, and that detects the amount of the transmitted X-rays
Data Source
AI summary
An apparatus for detecting an X-ray includes a photo diode having an anode electrode and a cathode electrode, a switching transistor, and a first storage capacitor that has one end connected to the cathode electrode and another end connected to the switching transistor.