Digital Detector with Monolithic Charge Integration
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Solution Overview
Problem
Current medical imaging systems face inefficiencies in converting X-ray photons into digital signals due to suboptimal charge-voltage integration and analog/digital conversion processes, leading to noise, distortion, and prolonged integration times, particularly due to the use of correlated double sampling and separate analog/digital converter blocks.
Innovation Solution
Integration of a charge preamplifier and analog/digital converter within a single monolithic integrated circuit, allowing for direct conversion of electrical charges from pixels into digital signals, reducing noise and processing time by eliminating the need for multiplexing and intermediate analog processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard integrator circuits with correlated double sampling are used for charge-to-voltage conversion, then noise correction is improved, but integration time increases prohibitively
Solution Approach 1:
The patent combines the integrator and analog-to-digital converter into a single monolithic integrated circuit, eliminating the need for separate CDS correction circuits and reducing integration time while maintaining noise correction capabilities through direct digital conversion
2Ease of manufacture
If separate analog-to-digital converter blocks are used downstream, then conversion functionality is provided, but parasitic effects and noise accumulate at interfaces
Solution Approach 1:
The integrator and analog-to-digital converter are merged into a single monolithic integrated circuit, eliminating multiple interfaces and reducing parasitic effects and noise accumulation while maintaining complete conversion functionality
3Ease of operation
If analog multiplexing is used to connect columns to the analog-to-digital converter, then channel routing is achieved, but additional noise and distortion are introduced
Solution Approach 1:
The patent replaces the analog multiplexing mechanism with direct digital conversion, eliminating the mechanical/analog switching process that introduces noise and distortion while maintaining channel routing capability through digital means
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 solution significantly reduces noise and processing time, enhances linearity and crosstalk performance, and minimizes signal disturbances, enabling rapid integration of pixel matrix charges with improved image quality and reduced component costs.
Implementation Method 1
a charge preamplifier connected to said column conductor, forming a preamplified column conductor and intended to integrate the charges carried by said column conductor
Implementation Method 2
at least one analog-to-digital converter connected in series with the preamplified column conductors, intended to convert the charges integrated at the output of the charge preamplifiers into a digital voltage
Implementation Method 3
a flat panel sensor positioned on the first monolithic substrate and comprising an array of pixels arranged in a matrix along rows and columns and configured to generate charges as a function of radiation striking the detector
Data Source
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AI summary
The invention relates to a digital detector (100) comprising a flat panel sensor and a first monolithic substrate and a second monolithic substrate, the flat panel sensor (11) being positioned on the first monolithic substrate, the detector comprising on the first monolithic substrate: a. an array of pixels (P(i,j)) arranged in a matrix (13) along rows and columns and configured to generate charges as a function of radiation; b. column conductors (Yj), each connecting the pixels (P(i,j)) of the same column and intended to carry the charges generated by the pixels (P(i,j)); on the second monolithic substrate: c. for each of the column conductors (Yj), a charge preamplifier (20) connected to the column conductor (Yj), forming a preamplified column conductor (21j) and intended to integrate the charges carried by said column conductor (Yj); d.at least one analog-to-digital converter (22j) connected in series with the pre-amplified column conductors (21j), intended to convert the integrated loads at the output of the load preamplifiers (20) into a digital voltage; e. a serializer block (23) connected to at least one analog-to-digital converter (22j), intended to generate an output voltage.