SPAD Array Dynamic Range Extension via Correction Curves
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Solution Overview
Problem
Current light detectors, particularly single-photon-avalanche diodes (SPADs), suffer from saturation issues due to their limited dynamic range, leading to non-linear response when faced with high photon counts, which restricts their ability to accurately measure light intensity in applications like fluorescence microscopy.
Innovation Solution
The implementation of a device with multiple detection areas formed from SPAD arrays, where each area has a signal output, and a correction curve is determined by combining and offsetting the key curves of these areas to achieve a linearized response across a broader dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-photon-avalanche diodes (SPADs) are used to detect low amounts of light, then the signal-to-noise ratio is improved, but the dynamic range is limited due to saturation at high photon counts
Solution Approach 1:
The detection area is divided into multiple independent SPADs arranged in an array. Each SPAD independently detects photons and generates signals, which are then processed to determine the total light intensity. This segmentation allows the detector to handle high photon counts by distributing the detection load across multiple elements, thereby extending the dynamic range while maintaining the high signal-to-noise ratio characteristic of individual SPADs.
2Productivity
If multiple SPADs are arranged in parallel to increase dynamic range, then the detection of high photon counts is improved, but the device complexity increases
Solution Approach 1:
Multiple SPADs are combined into a single integrated detector array structure with shared readout electronics and signal processing circuitry. The individual signals from each SPAD are merged and processed together to determine the total light intensity, reducing the overall complexity compared to having separate detection systems for each SPAD.
Solution Approach 2:
The SPAD array is designed to function across multiple detection modes and applications. The same detector structure can handle both low-light detection (maintaining high signal-to-noise ratio) and high-light detection (extending dynamic range), as well as potentially serving multiple wavelengths or detection schemes, thereby reducing the need for multiple specialized detectors.
3Productivity
If the detection area is increased to handle higher light intensities, then the dynamic range is improved, but the saturation behavior becomes more pronounced
Solution Approach 1:
The detection area is segmented into multiple smaller SPAD elements rather than using a single large detector. Each SPAD operates within its linear range, and the combined output of multiple SPADs provides the extended dynamic range. This segmentation prevents saturation in individual elements while maintaining measurement precision across the full detection range.
Solution Approach 2:
The detector utilizes the statistical distribution of photon arrivals across multiple SPADs to maintain linearity. By changing from a single large detection area to multiple smaller areas, the system exploits the probabilistic nature of photon detection to extend the linear dynamic range while preserving measurement precision through appropriate 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
This approach significantly enhances the dynamic range of light detection, allowing for more accurate measurement of light intensity, even at high photon counts, while maintaining the basic properties of the device and improving signal-to-noise ratio.
Implementation Method 1
an absorbed photon creates an electron hole pair in the semiconductor, which is accelerated by the strong electrical field and carries out further shock ionizations. This process continues like an avalanche and triggers a measurable load avalanche
Implementation Method 2
an absorbed photon creates an electron hole pair in the semiconductor
Data Source
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AI summary
The invention relates to a method for improving the dynamic range of a device for detecting light, preferably for use in a microscope, comprising at least two detection areas (8, 9), wherein the detection areas (8, 9) are each formed from an arrangement (array) (8, 9) of multiple single-photon avalanche diodes (SPAD), and wherein the detection areas (8, 9) each have at least one signal output (10, 11), wherein a characteristic curve (12, 13) is determined for each of the detection areas (8, 9), and wherein the characteristic curves (12, 13) are combined with one another and/or offset to obtain a correction curve (15) and/or a correction factor (17). The invention additionally relates to a device for detecting light, in particular for use in a microscope. Furthermore, the invention relates to a corresponding microscope.