LIBS Dispersion Module With Folded Grating Path for High Resolution
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Solution Overview
Problem
Existing laser-induced breakdown spectroscopy (LIBS) systems face limitations in achieving high resolution and compactness while maintaining efficient light collection and analysis, particularly in distinguishing closely spaced emission lines of elements like carbon and iron.
Innovation Solution
The system employs a dispersion module with reflective diffraction gratings configured for multiple reflections, allowing for a compact design with enhanced resolution, capable of distinguishing closely spaced emission lines by providing a dispersion rating of at least 20 mrad/nm and achieving resolutions of 10 pm, thereby improving the accuracy of elemental analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional spectrometer design is used, then light collection is efficient, but the device size is large and resolution is limited
Solution Approach 1:
The patent transitions from conventional linear optical paths to a folded optical path using multiple reflections between gratings. This dimensional reconfiguration allows the light to traverse a longer effective path length within a compact physical footprint, achieving high spectral resolution without proportionally increasing device volume
Solution Approach 2:
The optical components including gratings, mirrors, and beam paths are nested within a compact housing structure. The multiple reflection paths are arranged in a space-efficient configuration where optical elements are positioned to maximize path length while minimizing external dimensions, effectively nesting the optical train within a small form factor
2Measurement precision
If spectral resolution is increased to distinguish closely spaced emission lines, then elemental analysis accuracy improves, but device complexity increases
Solution Approach 1:
The spectral analysis function is segmented across multiple diffraction grating reflections rather than relying on a single high-resolution grating. Each grating reflection contributes incrementally to the overall dispersion, achieving high resolution through cumulative effect while using standard, off-the-shelf grating components that are simpler to manufacture and align
Solution Approach 2:
Multiple grating reflections act as intermediary steps in the spectral dispersion process. Rather than requiring a single complex high-resolution grating, the system uses multiple lower-order reflections as intermediaries to progressively separate wavelengths, simplifying the specification and fabrication of individual optical components
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
The solution enables accurate and efficient detection of elements with improved resolution, particularly in applications like scrap sorting and weld examination, allowing for precise differentiation of elements with closely spaced wavelengths, such as carbon and iron, and supports applications in fiber optic networks and telecom equipment analysis.
Implementation Method 1
The dispersion module employs a double grating configuration with reflective diffraction gratings configured for multiple reflections
Implementation Method 2
LIBS operate by focusing the laser beam onto a small area at the surface of the specimen When the laser beam is discharged it ablates a very small amount of material
Implementation Method 3
At the high temperatures during the early plasma, the ablated material dissociates (breaks down) into excited ionic and atomic species. During this time, the plasma emits a continuum of radiation
Data Source
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AI summary
A device for analyzing the material composition of a sample via plasma spectrum analysis includes a laser assembly configured to emit a beam for plasma spectrum analysis and an optical assembly configured to direct the beam towards a target for plasma spectrum analysis of the target. The optical assembly is configured to collect a plasma emitted light emitted from a plasma and provide the plasma emitted light to a dispersion module. The dispersion module includes a first and second diffraction gratings. The first diffraction grating and second diffraction grating are positioned within the dispersion module such that light received from the optical assembly contacts the first diffraction grating at least two times before being directed out of the dispersion module.