X-ray Imaging Apparatus AEC Integration Pixel Array
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Solution Overview
Problem
Conventional X-ray imaging systems with separate ionization chambers for automatic exposure control (AEC) face issues of reduced image quality, increased system complexity, and higher costs due to the need for additional components and circuits.
Innovation Solution
An X-ray imaging apparatus that integrates an AEC processing unit within the pixel array, utilizing a bias voltage source to detect current flowing between the bias voltage and pixels, and outputs an AEC signal without requiring additional apparatus or complex circuits, including a detector, integrator, comparator, and compensator to manage offset currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate ionization chamber is used for automatic exposure control, then the AEC function can be achieved, but the system complexity and cost increase due to additional components
Solution Approach 1:
The patent merges the AEC detection function with the existing pixel array structure by integrating AEC sensors into the pixel array. The bias voltage source provides voltage to both the pixels and AEC sensors through common electrodes, allowing current detection for AEC purposes without requiring a separate ionization chamber. This integration eliminates additional components while maintaining the AEC function.
Solution Approach 2:
The pixel array structure is designed to serve multiple functions: image detection through photodiodes and AEC detection through integrated AEC sensors. The bias voltage source and common electrodes are used for both pixel operation and AEC sensor operation, making the system more universal and reducing the need for separate dedicated components for each function.
2Reliability
If a separate ionization chamber is used for automatic exposure control, then the AEC function can be achieved, but the image quality deteriorates
Solution Approach 1:
By integrating AEC sensors within the pixel array structure rather than using a separate ionization chamber, the patent eliminates the interference that separate chambers cause to image quality. The AEC sensors share the same photodetector array and readout circuitry, ensuring that AEC detection does not degrade the quality of the captured images.
3Device complexity
If AEC sensors are installed in the pixel array, then the system complexity is reduced, but additional circuits are needed to operate gate driver and readout circuit during integration process
Solution Approach 1:
The patent enables the gate driver and readout circuit to operate continuously during both the integration process and readout process. By keeping these circuits active throughout, the system can detect AEC sensor currents during integration without requiring additional switching or circuit reconfiguration, thereby reducing manufacturing complexity despite the integrated sensor design.
4Device complexity
If AEC processing unit detects current flowing between bias voltage source and pixels, then additional apparatus is eliminated, but offset current compensation is required
Solution Approach 1:
The AEC processing unit includes an offset processor that uses feedback mechanisms to detect and compensate for offset currents. By continuously monitoring the current signal and applying corrective offset compensation, the system maintains accurate AEC detection despite the presence of offset currents, thereby simplifying the overall system while managing operational complexity through intelligent signal processing.
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 effective automatic exposure control without adding complexity or cost, maintaining image quality by detecting X-ray exposure through existing components, thereby reducing the risk of overexposure and improving system efficiency.
Implementation Method 1
a bias voltage source that provides a bias voltage to pixels detecting X-rays
Implementation Method 2
an automatic exposure control (AEC) processing unit that detects a current flowing between the bias voltage source and the pixels
Data Source
AI summary
The present invention relates to an X-ray imaging apparatus that includes a bias voltage source that provides a bias voltage to pixels that detect X-rays and an automatic exposure control (AEC) processing unit that detects a current flowing between the bias voltage source and the pixels and outputs an AEC signal.