Spectrometer Optical System with Movable Absorber and Filter
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Solution Overview
Problem
Spectrometer devices often require multiple entrance apertures and detectors to achieve optimal wavelength coverage and spectral resolution, leading to increased equipment costs and potential saturation issues, particularly due to intensity differences between lower and higher wavelength ranges.
Innovation Solution
An optical system with a single entrance aperture and reduced number of detectors, utilizing a grating for spectral dispersion, a mirror to reflect zero-order light, and movable absorber and filter elements to manage intensity differences between wavelength ranges, allowing sequential measurement of diffracted light without compromising wavelength coverage or spectral resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple entrance apertures and detectors are used to achieve optimal wavelength coverage and spectral resolution, then measurement precision and wavelength coverage are improved, but device complexity and equipment costs increase
Solution Approach 1:
The patent employs movable absorber and filter elements that can be dynamically positioned to control the intensity of zero-order light and first-order diffracted light. This dynamic adjustment allows a single detector to adapt to different wavelength ranges and intensity conditions, replacing the need for multiple fixed detectors while maintaining spectral resolution and wavelength coverage
Solution Approach 2:
The single detector is designed to measure both first-order diffracted light and zero-order light across different wavelength ranges by adjusting the positions of absorber and filter elements. This multi-functional capability allows one detector to perform the work of multiple detectors, reducing device complexity while maintaining measurement precision
2Adaptability or versatility
If multiple detectors are used to cover different wavelength ranges, then wavelength coverage is improved, but equipment costs and device complexity increase
Solution Approach 1:
The movable absorber element can be positioned to either block or transmit zero-order light, while the movable filter element can selectively transmit different wavelength ranges to the detector. This dynamic configuration enables a single detector to cover the full wavelength range that would otherwise require multiple detectors, reducing equipment costs and device complexity
Solution Approach 2:
By changing the optical parameters (intensity, wavelength transmission) through the movable absorber and filter elements, the system allows a single detector to operate effectively across different wavelength ranges. This parameter adjustment replaces the need for multiple detectors with fixed wavelength ranges, achieving versatile wavelength coverage with reduced device complexity
3Measurement precision
If the intensity of zero-order light is increased to improve signal strength, then measurement sensitivity is improved, but detector saturation occurs
Solution Approach 1:
The movable absorber element is positioned in the path of zero-order light to selectively absorb excess intensity. This extracts the harmful excessive intensity from the light beam before it reaches the detector, preventing saturation while maintaining sufficient signal strength for accurate measurement
Solution Approach 2:
The absorber element acts as an intermediary between the grating and the detector, controlling the intensity of zero-order light. This mediator absorbs excess intensity when necessary and allows full intensity when appropriate, protecting the detector from saturation while maintaining measurement sensitivity
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 configuration reduces equipment costs and sizes while effectively managing intensity differences, allowing for precise measurement of both lower and higher wavelength ranges without the need for additional attenuation means, thereby enhancing the operational efficiency of spectrometer devices.
Implementation Method 1
a grating for spectral dispersion of the primary light beam into a first fan of diffracted light within the first wavelength range
Implementation Method 2
a mirror element suitably positioned to reflect the primary zero order light beam by 180 degrees forming a secondary light beam
Implementation Method 3
an absorber element (or beam shutter) movably mounted to be reversibly placed within the primary zero order light beam between the grating and the mirror element
Data Source
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AI summary
The invention relates to an optical system (1), to a spectrometer device (20) comprising such optical system and to a method (100) to operate such an optical system comprising an entrance aperture for entering primary light (LP) containing both a first, lower wavelength range (R1) and a second, higher wavelength range (R2) into said optical system, a grating (3) for spectral dispersion of the primary light beam into a first fan of diffracted light (LD1) within the first wavelength range and a primary zero order light beam, a mirror element (4) suitably positioned to reflect the primary zero order light beam (LZ) back as secondary light beam (SL) to the grating (3) where it is dispersed into a second fan of diffracted light within the second wavelength range, a detector arrangement (5) with detectors (51), an absorber element (6) to be reversibly placed within the primary zero order light beam, and a filter element (7) to be reversibly placed within the primary light beam, wherein the detector arrangement (5) is adapted to measure the first fan of diffracted light (LD1) in case of the absorber element (6) being placed within the primary zero order light beam (LZ) to absorb the primary zero order light (LZ) and the filter element (7) being positioned outside the primary light beam (LP), and to measure the second fan of diffracted light (LD2) in case of the filter element (7) being arranged within the primary light beam (LP) to filter out the first wavelength range (R1) out of the primary light beam (LP) and the absorber element (6) being positioned outside the primary zero order light beam (LZ).