Tandem Diffraction Grating Monochromator Data Knitting
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Solution Overview
Problem
Conventional monochromators face challenges in achieving high precision and quality spectral measurements across a wide spectral range due to variations in intensity and linearity of diffracted bands of light, leading to increased signal-to-noise ratios and errors.
Innovation Solution
A tandem dispersive range monochromator employing a tandem diffraction grating with two separate dispersive surfaces, controlled by processing circuitry to rotate and adjust the angular velocity of each grating individually, and data knitting to combine measurements from both gratings, providing a spectrum of combined data values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diffraction grating is used to cover a wide spectral range, then the device complexity is reduced, but the measurement precision deteriorates due to variations in intensity and linearity across different wavelength regions
Solution Approach 1:
The patent divides the diffraction grating system into two separate gratings, each optimized for a specific spectral region (UV-Vis and NIR). This segmentation allows each grating to maintain high measurement precision in its designated range while collectively covering a wide spectral range, resolving the contradiction between device simplicity and measurement precision.
Solution Approach 2:
Each diffraction grating is designed with specific local properties optimized for its target spectral region. The first grating has characteristics optimized for UV-Vis wavelengths while the second grating is optimized for NIR wavelengths. This local optimization ensures high measurement precision in each region without requiring a complex single-grating solution.
2Productivity
If the angular velocity of the diffraction grating is increased to improve productivity, then the spectral range coverage speed is improved, but the measurement precision deteriorates due to reduced time for accurate detection at each wavelength
Solution Approach 1:
The patent implements dynamic control of the grating rotation system, allowing the angular velocity to be adjusted based on the specific spectral region being scanned and the required measurement precision. This dynamic adjustment enables the system to maintain high productivity while ensuring sufficient detection time at each wavelength, resolving the contradiction between scanning speed and measurement precision.
3Measurement precision
If a tandem diffraction grating system with individual control is used, then the measurement precision is improved through optimized spectral resolution, but the device complexity increases due to multiple control mechanisms
Solution Approach 1:
The patent designs the control system to perform multiple functions: it controls both gratings independently for spectral resolution optimization, coordinates the switching between gratings based on wavelength region, and manages the data knitting process. This multi-functional control approach, while increasing complexity, provides the necessary precision for wide-range spectroscopy and represents an acceptable trade-off for achieving the measurement goals.
4Measurement precision
If separate diffraction gratings are used for different spectral regions, then the measurement precision is improved, but the device complexity and data processing requirements increase due to the need to knit data from multiple sources
Solution Approach 1:
The patent introduces a data knitting process that acts as an intermediary between the separate spectral measurements from different gratings. This intermediary process combines the data sets, aligns them across the spectral range, and produces a unified high-precision spectrum, making the complexity of multiple gratings manageable and worthwhile for achieving superior measurement precision.
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
Enables high precision and quality spectral measurements across a wider range, reducing signal-to-noise ratios and errors by compensating for variations in intensity and linearity, and optimizing spectral resolution for multiple spectral regions.
Implementation Method 1
A diffraction grating comprises an optical element having a periodic structure that separates and diffracts broadband light into its constituent wavelength components
Implementation Method 2
The components may be separated in direction after reflection, based on a spacing of the periodic structure of the grating
Data Source
AI summary
Aspects of a tandem dispersive range monochromator and data knitting for the monochromator are described herein. In one embodiment, the monochromator includes a tandem diffraction grating, a grating drive motor that rotates the tandem diffraction grating to provide, by diffraction of broadband light, first dispersed wavelengths of light and second dispersed wavelengths of light, a detector that detects a first reflection from the first dispersed wavelengths of light and a second reflection from the second dispersed wavelengths of light, and processing circuitry that knits together data values from the first reflection and data values from the second reflection to provide a spectrum of combined data values. By using a tandem diffraction grating having different dispersive surfaces, measurements of relatively high precision and quality may be taken throughout a wider spectral range, and the measurements may be knitted together to provide a spectrum of combined data values.