Spatially Variable Filter Spectrometer Distortion Correction
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Solution Overview
Problem
Existing spectrometers suffer from distortions in spectral measurements due to non-uniform light intensity distribution across spatially variable filters, which is problematic for compact spectrometers that measure samples at various positions and orientations.
Innovation Solution
A compact spectrometer system with an improved spatially variable filter that adjusts output spectral data by using a plurality of spaced apart filter regions with similar and different transmission profiles, coupled with a detector and processor to measure and adjust for spatial variations in light intensity, reducing distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spatially variable filter is used to separate wavelengths in a compact spectrometer, then the spectrometer can be made more compact and versatile for measuring samples at various positions and orientations, but distortions are introduced into the output spectrum due to non-uniform light intensity distribution across the filter
Solution Approach 1:
The spatially variable filter is divided into multiple discrete filter regions, each with a specific transmission profile. By segmenting the filter into distinct regions rather than using a continuous gradient, the system can measure light intensity at multiple discrete points across the filter surface. This segmentation enables the detector to capture spatial variation data that can be used to correct for non-uniform illumination, thereby maintaining measurement accuracy while preserving the compact design's versatility.
Solution Approach 2:
The system uses feedback by comparing measurements from multiple filter regions to detect and correct for non-uniform light intensity distribution. The processor analyzes the output signals from detector elements corresponding to different filter regions and uses this information to adjust and correct the spectral measurements. This feedback mechanism compensates for illumination variations, ensuring accurate spectral data is obtained even when the spectrometer is used at various positions and orientations.
2Loss of information
If prior spatially variable filters are used, then wavelength separation is achieved, but the position and orientation of the input window with respect to the sample plane cause distortions in the output spectrum
Solution Approach 1:
The filter is segmented into multiple discrete regions with different transmission profiles positioned at different locations. This segmentation allows the system to sample light intensity at multiple discrete points across the filter surface, enabling detection of position and orientation variations. By having multiple discrete measurement points rather than relying on a continuous gradient, the system can identify and correct for illumination non-uniformity caused by input window misalignment, thereby reducing spectral distortions.
Solution Approach 2:
The system changes the parameter of having multiple discrete filter regions with specific transmission profiles at different locations, rather than using a traditional continuous gradient filter. This parameter change enables the system to be less sensitive to input window position and orientation because the discrete regions provide multiple reference points for detecting and correcting illumination variations, thereby maintaining spectral accuracy across different operational configurations.
3Adaptability or versatility
If incident light has non-uniform intensity distribution across the filter area, then the spectrometer can operate with various sampling configurations, but distortions are produced in the spectral representation of the measured sample
Solution Approach 1:
The filter is divided into multiple discrete filter regions, each with a defined transmission profile at a specific location. This segmentation enables the detector to measure light intensity at multiple discrete points across the filter surface. By having multiple discrete measurement points, the system can detect the spatial variation pattern of non-uniform illumination and use this information to correct the spectral representation, thereby maintaining accuracy while allowing flexible sampling configurations.
Solution Approach 2:
The system implements feedback by using measurements from multiple filter regions to detect non-uniform light intensity distribution and automatically correct the spectral output. The processor analyzes the relative intensities from different filter regions and applies correction algorithms to compensate for illumination non-uniformity. This feedback mechanism ensures accurate spectral representation is maintained regardless of the sampling configuration or incident light distribution pattern.
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 system generates adjusted spectra with reduced distortions, providing more accurate spectral information by compensating for light intensity variations, thus enhancing the reliability of spectral measurements across different sampling conditions.
Implementation Method 1
A linear variable filter can be generally configured to have a plurality of transmission profiles, that vary across a length of the filter. Collimated light incident on the linearly variable filter may be spectrally separated by the filter, based on the location at which the incident light hits the filter.
Implementation Method 2
A detector optically coupled to the filter can detect the intensity of incident light at different wavelengths.
Data Source
AI summary
An improved compact spectrometer system comprising an improved spatially variable filter is disclosed herein. A spatially variable filter may be configured to have a plurality of different transmission profiles at different locations of the filter, to spectrally separate light incident on the filter. The spatially variable filter may comprise a plurality of different filter regions having different transmission profiles, and a plurality of similar filter regions comprising similar transmission profiles. The spatially variable filter may be optically coupled to a detector comprising a plurality of detector elements configured to measure the intensity of light. The measurement data generated by the plurality of detector elements coupled to the plurality of similar filter regions can be used to determine a spatial variation on incident light intensity.