Detector Circuit With Programmable Dark Current Neutralization
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Solution Overview
Problem
Digital high-energy radiation imaging devices face distortion due to dark current, which is indistinguishable from photo current and consumes a part of the detector's capacity, leading to inaccurate image representation and potential curvature of electric field lines causing image distortion.
Innovation Solution
A programmable current source is used to provide a neutralizing charge to counteract the dark current, allowing for more accurate representation of photo current and reducing image distortion by eliminating or minimizing the effect of dark current, potentially eliminating the need for guard rings and reducing pixel gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If guard rings are used to reduce dark current effects, then image distortion is reduced, but gaps between active imaging areas increase and device complexity increases
Solution Approach 1:
The patent extracts the dark current compensation function from the structural guard ring and relocates it to the electronic domain through a programmable current source. This removes the need for physical guard rings while maintaining dark current correction capabilities, thereby eliminating the gaps they create between active imaging areas.
Solution Approach 2:
The patent replaces the mechanical/structural guard ring system with an electronic current source system. Instead of using physical structures to manage dark current, the invention uses programmable electrical current to counteract dark current effects, achieving the same goal without the spatial overhead of guard rings.
2Measurement precision
If guard rings are used to reduce dark current effects, then image distortion is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the dark current compensation function from the complex guard ring structure and implements it through a programmable current source with control logic. This approach maintains image accuracy while potentially reducing overall device complexity by using standard semiconductor components rather than specialized guard ring structures.
3Measurement precision
If detector capacity is increased to handle dark current, then image accuracy improves, but detector capacity is consumed by dark current
Solution Approach 1:
The patent converts the harmful dark current into a manageable parameter by measuring it separately and using it to program the compensating current source. Instead of treating dark current as noise to be tolerated within limited detector capacity, the invention uses it as information to generate an equal and opposite corrective current, effectively eliminating its harmful impact.
Solution Approach 2:
The patent introduces a programmable current source as an intermediary between the detector and the readout electronics. This intermediary measures the dark current, processes it through control logic, and generates a compensating current that is added to the photo current signal, thereby separating the dark current management function from the primary detection function.
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 enhances image accuracy by isolating the photo current, reducing distortion, and allowing for smaller pixel gaps, thereby improving the overall performance of digital imaging devices.
Implementation Method 1
The detector substrate is made of a photo-conductor material which converts incoming radiation into electronic signals
Implementation Method 2
a capacitor coupled with the detector substrate, the capacitor arranged to collect an electrical charge from the detector substrate
Data Source
AI summary
Some embodiments include an imaging system comprising a detector substrate, at least one detector circuit comprising a capacitor coupled with the detector substrate, the capacitor arranged to collect an electrical charge from the detector substrate, and the imaging system further comprises at least one programmable current source, arranged to provide a neutralizing charge to the capacitor, and the imaging system is configured to select a value for the neutralizing charge in dependence of a frame number.