Detector Subpixel Segmentation for Dead Time Reduction

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Solution Overview

Problem

Current detector arrangements face challenges with dead times during image acquisition and signal distortion due to permanent sensitivity during readout, leading to misfits and artefacts, especially in time-critical applications like polarimetry and spectroscopy.

Innovation Solution

A detector arrangement with subpixels that can be switched between sensitive and insensitive states, using DEPFETs with potential barriers to selectively allow signal charge collection, minimizing dead times and signal interference during readout.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an electronic shutter is implemented using conventional methods, then exposure time control is improved, but dead time increases and measurement precision deteriorates

Engineering Contradiction:
Improveexposure time controlVSAvoiddead time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Each pixel is divided into multiple subpixels, with each subpixel having its own DEPFET that can be independently controlled. This segmentation allows different subpixels within the same pixel to be in different operational states (sensitive or insensitive), enabling continuous measurement capability while maintaining precise exposure control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensitivity state of individual subpixels is dynamically switchable through control of the DEPFETs. This dynamic control allows the system to adapt the sensitivity of each subpixel independently, enabling the sensor to remain partially sensitive even during readout operations, thereby reducing dead time while maintaining exposure control precision.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the sensor remains permanently sensitive during readout, then productivity is improved, but signal distortion increases and measurement precision deteriorates

Engineering Contradiction:
Improvecontinuous measurement capabilityVSAvoidsignal accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

By dividing each pixel into multiple subpixels with independent DEPFET control, the system can segment the sensor into sensitive and insensitive regions. This allows continuous measurement in sensitive subpixels while insensitive subpixels undergo readout, maintaining productivity without signal distortion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different subpixels within the same pixel can have different sensitivity states locally. This local quality differentiation enables some subpixels to remain sensitive and collect signals continuously while others are made insensitive during readout, resolving the contradiction between continuous measurement and signal accuracy.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If mechanical shutters are used to control exposure, then manufacturing precision is improved, but speed deteriorates and device complexity increases

Engineering Contradiction:
Improveexposure time precisionVSAvoidshutter response speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces mechanical shutter systems with an electronic control mechanism based on DEPFETs. The electronic switching of DEPFETs provides both the precision needed for exposure control and the high speed response required, eliminating the limitations of mechanical shutters while maintaining manufacturing precision through controlled electrical fields.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 minimizes dead times and suppresses misfits, enabling high selectivity in charge collection and maintaining spectroscopic quality even with high parallelization, while avoiding additional dead time and artefacts.

Implementation Method 1

The potential barriers for shielding the insensitive switched subpixel originate from shield electrodes within the region of the insensitive subpixel and extend towards the source region of the insensitive DEPFET so that the internal gate of the insensitive DEPFET is shielded from signal electrons.

Methodology Applied
Scientific EffectPotential barriers: Electric Field

Data Source

PatentEP2942812B1Detector assembly and corresponding operating method
Publication Date: 2018.09.05 MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN EV
  • EP2942812B1 patent drawingFigure 1A~1B
  • EP2942812B1 patent drawingFigure 1C
  • EP2942812B1 patent drawingFigure 1D

AI summary

The invention relates to a detector arrangement for the detection of radiation, in particular particle radiation or electromagnetic radiation, comprising a semiconductor detector with multiple pixels for radiation detection. It is proposed that each individual pixel has a first subpixel (1) and a second subpixel (2). The semiconductor detector is switchable between a first collection state in which the first subpixel (1) is sensitive and the second subpixel (2) is insensitive, so that radiation-generated signal charge carriers are collected essentially only in the first subpixel (1), and a second collection state in which the second subpixel (2) is sensitive and the first subpixel (1) is insensitive, so that the radiation-generated signal charge carriers are collected essentially only in the second subpixel (2).Furthermore, the invention includes a corresponding operating method as well as detector arrangements based on the same concept with a higher number of subpixels per pixel.