Overlapping Spectral Images in Compact Optical Spectrometer
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Solution Overview
Problem
Conventional optical spectrometers require large detector arrays due to the wide spectral range of dispersed light, leading to bulky devices, and existing solutions like the Battey device are not ideal for all circumstances.
Innovation Solution
A spectrometer design that overlaps images of different wavelength components and uses a spatial filter, dispersion system, and two-dimensional detector array to remove ambiguity, allowing for a compact form factor by overlapping images in at least one direction, with a processor to disambiguate the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional gratings are used to accommodate wide spectral range, then spectral range is improved, but detector array area increases leading to larger spectrometer size
Solution Approach 1:
The patent transitions from one-dimensional spectral dispersion to two-dimensional dispersion by introducing a second grating that disperses light in a direction perpendicular to the first grating. This allows wavelength components to be distributed across both dimensions, enabling compact detector array by utilizing vertical overlap in the second dimension while maintaining wide spectral coverage in the first dimension.
Solution Approach 2:
The patent implements nested dispersion by placing a second grating within the optical path of the first grating, where the second grating disperses already-dispersed light in a perpendicular direction. This nested arrangement allows multiple spectral subsets to be folded onto overlapping regions of the detector array, effectively nesting spectral information within a compact spatial footprint.
2Measurement precision
If all wavelengths are shifted along a single direction, then spectral separation is improved, but detector array width increases
Solution Approach 1:
The patent introduces a second dispersion direction perpendicular to the first, transforming single-direction wavelength separation into two-dimensional separation. This allows the detector array to utilize both horizontal and vertical dimensions for spectral discrimination, reducing the required width in the first direction while maintaining precise spectral separation through the combined two-dimensional mapping.
3Length of stationary object
If Battey device folds spectral ranges onto non-overlapping rows, then detector array width is reduced, but device complexity increases and is not ideal for all circumstances
Solution Approach 1:
The patent introduces dynamic spectral folding by using a second grating that can be positioned at different angles relative to the first grating. This allows flexible adjustment of the dispersion directions and the degree of overlap between spectral subsets, enabling optimization for different application requirements while maintaining compact detector array dimensions.
Solution Approach 2:
The patent employs variable parameters including the angle between the two gratings, the dispersion characteristics of each grating, and the positioning of spectral subsets to optimize the balance between detector array size and spectral resolution. These adjustable parameters allow adaptation to different spectral ranges and detector capabilities.
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 design reduces the size of the detector system while maintaining spectral resolution, allowing for more compact and efficient optical spectrometers that can handle wide spectral ranges without the need for large physical detector arrays.
Implementation Method 1
The spatial filter spatially filters the incident light
Implementation Method 2
The dispersion system disperses images of the spatial filter in a wavelength dependent fashion onto the detector system
Implementation Method 3
Detector elements in the detector array convert sensed light to an electrical output signal
Data Source
AI summary
An optical spectrometer distinguishes ambiguity between different wavelength constituent components present in incident light. A spatial filter in the spectrometer spatially filters the incident light. A dispersion system receives the spatially filtered light and disperses images of the spatial filter in a wavelength dependent fashion such that two or more wavelength-specific images at least partially overlap at a detector system. The detector system comprises a detector array and processor that detects and processes the dispersed light to remove ambiguity between one or more of the overlapping images. The detector array may detect coded aperture images associated with a coded aperture spatial filter defined by a coded aperture function, and the processor may process the detector array output signals using an analysis function that complements the coded aperture function. The detector system may filter the spatial filter images and electronically process the resulting detector array output signals.