Hyperspectral Imaging Device with Convex Diffraction Grating Demagnification
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Solution Overview
Problem
Existing hyperspectral imagers are either too bulky or restrictive regarding the observed wavelength range, and there is no compact hyperspectral imager providing a broad spectral range from UV to short wavelength infrared (SWIR) without compromising hyperspectral image quality.
Innovation Solution
A spectral imaging device with a new optical design featuring two concave mirrors and a convex diffraction grating with a complex invariant shape class, which introduces a demagnification function to increase photon collection and correct in-field aberrations over a broad spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hyperspectral imager designs are used, then spectral imaging capability is achieved, but the device becomes bulky and restricted in wavelength range
Solution Approach 1:
The patent merges the spectral dispersion function and the focusing function into a single integrated optical path using a convex diffraction grating that simultaneously disperses wavelengths and focuses light onto the detector plane, eliminating the need for separate dispersion and imaging optical trains
Solution Approach 2:
The patent introduces a demagnification dimension by placing a demagnification lens between the convex grating and the detector, creating a scaled-down image on the detector plane that allows broader spectral coverage without proportionally increasing device volume
2Reliability
If larger pixels are used to increase photon collection, then signal-to-noise ratio improves, but spatial resolution decreases due to lower pixel density
Solution Approach 1:
The patent changes the magnification parameter of the optical system by introducing a demagnification lens with a specific focal length that reduces the image scale on the detector, allowing smaller pixels to capture the same spatial information with higher density while maintaining adequate signal levels through the demagnified but concentrated light path
3Volume of moving object
If demagnification is introduced to reduce device size, then compactness improves, but optical aberrations increase
Solution Approach 1:
The patent introduces a field lens as an intermediary optical element between the convex grating and the demagnification lens that serves as an aberration correction station, compensating for optical distortions introduced by the demagnification process and maintaining image quality in the 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 solution allows for a compact, high-resolution hyperspectral imager with improved signal-to-noise ratio, reduced size and weight, and the ability to cover a wide spectral range without compromising image quality.
Implementation Method 1
a convex diffraction grating with a complex invariant shape class... performs the spectral dispersion function
Implementation Method 2
two concave mirrors and a convex diffraction grating... After its reflection by the first concave mirror, the light beam is then diffracted and reflected by the convex diffractive reflective grating towards the second concave mirror
Data Source
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AI summary
Spectral imaging device (100) comprising: - a slit (40); - a first concave mirror (10); - a convex reflective diffractive grating (20) comprising a reflective surface (21) on which a diffractive grating (22) is formed; - a second concave mirror (30); - a first matrix detection means (50); said reflective surface (21) of said convex reflective diffractive grating (20) is defined by a complex invariant shape class; said first concave mirror (30), said convex reflective diffraction grating (20), and said second concave mirror (30) being configured such that a spectrally dispersed image of the slit (40) with said slit length A is produced on the detection means (50) with an image length B, said slit length A and image length B defining a demagnification such that : demagnification factor = (Formula (I)) said demagnification factor being higher than 1.3.