Handheld Plasma Spectrometer Optical Path Design
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Solution Overview
Problem
Existing hand-held devices for plasma spectrum analysis are bulky and complex, often relying on multiple mirrors to reflect both laser and plasma light, which is inefficient and not suitable for portable, hand-held applications.
Innovation Solution
A hand-held device with a manually held casing containing a laser housing, a first mirror angled acutely to the laser projection axis to receive plasma light, a second focusing mirror to reflect it back, and an optical fibre to direct the plasma light to a spectral analyser, allowing for efficient plasma spectrum analysis without the need for multiple mirrors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple mirrors are used to reflect both laser and plasma light, then the device can perform plasma spectrum analysis, but the device becomes bulky and complex
Solution Approach 1:
The patent extracts the laser beam path from the optical system by using a right-angle prism to deviate the laser beam 90 degrees before it reaches the sample. This separates the laser illumination path from the plasma light collection path, allowing the mirrors to be optimized solely for plasma light reflection without needing to accommodate the laser beam, thereby reducing overall system complexity
Solution Approach 2:
The patent introduces a right-angle prism as an intermediary optical element that deviates the laser beam 90 degrees. This intermediary component acts as a mediator between the laser source and the sample, enabling the laser to illuminate the sample at a right angle while the plasma light is collected by mirrors positioned at a different angle, thus simplifying the overall optical configuration
2Reliability
If multiple mirrors are used to reflect both laser and plasma light, then the device can perform plasma spectrum analysis, but the device becomes unsuitable for portable, hand-held applications
Solution Approach 1:
The patent extracts the laser beam path from the optical system by using a right-angle prism to deviate the laser beam 90 degrees before it reaches the sample. This separates the laser illumination path from the plasma light collection path, allowing the mirrors to be optimized solely for plasma light reflection without needing to accommodate the laser beam, thereby reducing overall system complexity
Solution Approach 2:
The patent segments the optical system into distinct functional modules: a laser module that illuminates the sample, a plasma generation zone where the laser interacts with the sample, and a light collection module with mirrors positioned to collect plasma light at specific angles. This segmentation allows each module to be optimized independently and compactly arranged in a hand-held configuration
3Device complexity
If the same mirrors are used to reflect both laser and plasma light, then the optical system can be simplified, but the efficiency of plasma light collection is reduced
Solution Approach 1:
The patent extracts the laser beam path from the optical system by using a right-angle prism to deviate the laser beam 90 degrees before it reaches the sample. This separates the laser illumination path from the plasma light collection path, allowing the mirrors to be optimized solely for plasma light reflection without needing to accommodate the laser beam, thereby reducing overall system complexity
Solution Approach 2:
The patent applies local quality optimization by positioning the first mirror at a 45-degree angle to the sample surface normal to collect plasma light emitted at specific angles, and the second mirror at a different angle to redirect the light to the detector. Each mirror is optimized for its specific function in the light collection path, maximizing plasma light collection efficiency while maintaining a compact configuration
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 device provides a compact and efficient means for analyzing material composition by establishing a plasma and directing the plasma light to a spectral analyser, enabling real-time analysis of object constituents with improved portability and reduced complexity.
Implementation Method 1
a laser generator (18) that emits laser pulses that are focused on the surface of a material to be analyzed
Implementation Method 2
a first mirror mounted in the housing for receiving plasma emitted light within the openings via the openings, the mirror being to one side of the projection axis with its normal axis acutely angled to the projection axis for the plasma light to the other side of the projection axis
Implementation Method 3
a second, focusing mirror mounted in the housing for receiving the plasma light reflected by the first mirror and reflecting it back again to the first side of the projection axis
Implementation Method 4
an optical fibre to direct the plasma light to a spectral analyser
Data Source
AI summary
A device (1) for analyzing the material composition of an object (2) has a casing (3) with a handle (4), an operating trigger (5), a window (6) for abutment against the object to be analyzed and a display (7) for displaying the analysis of the object. Mounted in the casing is a housing (11) having a base (12) to which it is pivotally connected about an axis (14) at one end (15). At the other end (16), a stepper motor (17) is provided for traversing the end across the base. This end has an opening (18) generally in alignment with an opening (19) in the housing in which the window is mounted. Within the housing, are mounted: a laser diode (21); a laser amplification crystal (22); a collimating lens (23); a laser focusing lens (24). The components are arranged on a laser projection axis (25), which passes out through the openings (18,19). A plane mirror (32) can receive light emitted by a plasma P excited at the surface of the object (2). Light from the plasma P is reflected in the direction (34) across the projection axis to a curved focusing mirror (35). From this mirror, the light is reflected again across the projection axis and focused on the end of an optical (fiber (37) set in an aperture (38) in the side wall (39) of the housing opposite from the reflecting mirror.