X-ray Detector Noise Reduction via Electrode Offset
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Solution Overview
Problem
Continuous photodiode digital X-ray detectors face electronic noise performance degradation due to increased capacitance in the data readout lines, which affects the noise performance and settling time compared to patterned photodiode detectors.
Innovation Solution
Controlling the parasitic capacitance between the data readout lines and the electrode of the continuous photosensor by specifying a spatial relationship between the electrode and the data readout lines, which can be achieved through the deposition of a dielectric layer and careful alignment of the electrode and photoelectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous photodiode structure is used, then fill factor and quantum efficiency are improved, but electronic noise performance degrades due to increased capacitance
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the continuous photodiode electrode and the data readout line. This dielectric layer acts as a mediator that reduces the parasitic capacitance coupling between the electrode and readout line, thereby decreasing electronic noise while preserving the continuous photodiode structure's high fill factor and quantum efficiency advantages
2Reliability
If continuous photodiode structure is used, then fill factor is improved, but settling time increases due to increased capacitance
Solution Approach 1:
The dielectric layer serves as a mediator that reduces the parasitic capacitance between the continuous photodiode electrode and data readout line. By lowering this capacitance, the time constant of the readout circuit is reduced, enabling faster settling times while maintaining the high fill factor benefits of the continuous photodiode structure
3Manufacturing precision
If electrode is positioned close to data readout line, then capacitance control is achieved, but coupling effect increases
Solution Approach 1:
The dielectric layer is positioned between the electrode and data readout line to reduce parasitic coupling. By carefully controlling the dielectric's position, thickness, and material properties, the patent achieves precise capacitance control while minimizing harmful coupling effects between the electrode and readout line
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 improves the readout speed and reduces electronic noise in X-ray detectors, enhancing their performance compared to conventional continuous photodiode detectors.
Implementation Method 1
a continuously formed, unpatterned photoelectric material of a photosensor... configured to generate electrical signals in response to incident X-rays
Implementation Method 2
controlling the load capacitance of the data readout lines by controlling a parasitic capacitance between the data readout lines and an electrode of the continuous photosensor
Data Source
AI summary
Exemplary embodiments are directed to imagining detectors and methods of fabricating the imagining detectors for use in medical imagining systems. In exemplary embodiments, a detector for an imaging device include a continuous unpatterned photoelectric material that forms a portion of a photosensor and an electrode disposed with respect to the photoelectric material to form an anode or cathode of the photosensor. Data readout lines connected to the outputs of transistors of the detector can be susceptible electronic noise from capacitive coupling between the electrode of the photosensor. In exemplary embodiments of the present disclosure, a lateral offset and/or vertical offset between the electrode and the data readout lines can be formed to control the capacitive coupling between the electrode and the data readout line.