Cascaded Charge Storage for Spectrometer Dynamic Range
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Solution Overview
Problem
Existing optical emission spectrometers face challenges in determining intensity ratios of spectral lines due to limited dynamic measurement range, poor signal-to-noise ratio, and complexity in preselecting amplification settings for CMOS sensors, leading to inaccurate concentration ratio determinations.
Innovation Solution
The implementation of a charge storage assembly with cascading charge storage devices that distribute charges across multiple capacitors, allowing for precise, low-noise measurements by enabling or disabling charge storage devices based on storage levels, thereby enhancing the signal-to-noise ratio and enabling dynamic measurement range adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photodetectors arranged along a line in CMOS technology are used to detect spectrally decomposed light, then it is possible to record a quasi-continuous spectrum within the covered spectral range and the system is cost-effective and universally suitable for many applications, but the dynamic measurement range is relatively small and the signal-to-noise ratio is poor
Solution Approach 1:
The charge storage assembly is divided into multiple individual charge storage devices (first, second, third charge storage devices) that can be independently controlled. Each charge storage device can store charges from the photodiode independently, allowing the system to handle a wide range of signal intensities by selectively activating appropriate storage devices based on the expected signal strength, thereby expanding the dynamic measurement range while maintaining universal applicability
Solution Approach 2:
The system dynamically selects which charge storage devices to activate based on the measurement requirements. The controller can enable or disable specific charge storage devices during measurement, allowing the dynamic measurement range to be adaptively adjusted for different applications without requiring physical reconfiguration, thus maintaining universal suitability while optimizing measurement precision for each specific case
2Productivity
If photodetectors arranged along a line in CMOS technology are used to detect spectrally decomposed light, then it is possible to record a quasi-continuous spectrum within the covered spectral range, but the signal-to-noise ratio is relatively poor and determination of intensity ratios is difficult
Solution Approach 1:
By segmenting the charge storage function into multiple independent charge storage devices, the system can allocate charges to appropriate storage devices based on intensity levels. This segmentation allows weak signals to be stored in dedicated devices without being overwhelmed by strong signals, improving the signal-to-noise ratio for weak spectral lines while maintaining the ability to record the entire quasi-continuous spectrum
Solution Approach 2:
Different charge storage devices can be optimized for different signal intensity ranges. The system applies different storage characteristics to different parts of the spectrum by selectively activating specific charge storage devices for specific spectral regions or intensity ranges, thereby improving the signal-to-noise ratio locally for weak signals while preserving the overall spectral recording capability
3Measurement precision
If single channel detectors are arranged on a carrier in accordance with the expected position of spectral lines to be measured, then high sensitivity with low noise and great dynamic measurement range are achieved, but production costs increase with the number of desired spectral lines and the measurable spectral lines are limited by installation space
Solution Approach 1:
The CMOS sensor with multiple photodetectors arranged along a line can detect the entire spectral range simultaneously, making the system universally applicable to many different measurement tasks without requiring custom configurations. This multi-functional approach replaces the need for multiple specialized single-channel detectors, reducing production costs while maintaining high sensitivity through the photodetector array architecture
Solution Approach 2:
The invention merges the functions of multiple single-channel detectors into a single CMOS sensor array with shared readout electronics and charge storage assembly. This consolidation reduces the overall device complexity and production costs while maintaining the ability to detect multiple spectral lines simultaneously with high sensitivity, as the photodetector array processes the entire spectrum in parallel
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 allows for simultaneous measurement of all spectral components with improved signal-to-noise ratio and dynamic range, simplifying the determination of intensity ratios and concentration ratios without prior knowledge of spectral line strengths or locations, and enabling flexible adaptation to specific measurement tasks through software adjustments.
Implementation Method 1
a photodiode P1 for detection of a spectral component S1 of the emitted, spectrally decomposed light
Implementation Method 2
a charge storage assembly 23 having a plurality of individual charge storage devices 31-34, wherein the charge storage devices are interconnectable in cascading fashion
Data Source
AI summary
An optical emission spectrometer has an excitation device for a sample to be examined, a dispersive element for spectrally decomposing light emitted by an excited sample, a multiplicity of photodiodes, which are arranged such that different spectral components of the emitted, decomposed light are detectable with different photodiodes, and a multiplicity of electronic readout systems for the photodiodes. A respective electronic readout system has a charge storage assembly comprising a plurality of individual charge storage devices, wherein the charge storage devices are interconnectable in cascading fashion, with the result that charges flowing in from an associated photodiode successively fill the charge storage devices. The respective electronic readout system can be used to read the charges of the individual charge storage devices of the charge storage assembly and/or the charges of subsets of the charge storage devices of the charge storage assembly.