Folded Hyperspectral Spectrometer Layout for Compact High Resolution
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Solution Overview
Problem
Existing hyperspectral imaging apparatuses are limited by their long length, require transmission gratings with limited resolution and alignment sensitivity, and face thermal issues, hindering compactness and performance.
Innovation Solution
Employing a reflective grating and a folded optical path configuration with a deflection mirror to create a compact spectrometer module, utilizing a reflective grating for high signal-to-noise ratio and wide field of view, and incorporating a dichroic filter for improved signal deflection and compact fore-optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear optical light signal pathway is used in the spectrometer module, then the optical components can be arranged in a simple linear configuration, but the total length of the spectrometer module becomes excessively long (222 mm)
Solution Approach 1:
The patent introduces a folded optical path that redirects the light signal in multiple directions using mirrors and prisms, transforming the linear one-dimensional arrangement into a two-dimensional folded configuration. This allows the optical components to be arranged in a compact folded layout rather than extending linearly, reducing the overall module length from 222 mm to a much more compact dimension while maintaining all necessary optical functions.
2Device complexity
If a transmission grating is used for spectral dispersion, then the grating can be positioned in the linear optical path, but the resolution is limited by the number of lines per unit length and alignment sensitivity increases
Solution Approach 1:
The patent replaces the traditional transmission grating with a reflection grating configuration. This substitution changes the fundamental mechanism of spectral dispersion from transmission-based to reflection-based, enabling higher spectral resolution through increased line density while reducing alignment sensitivity. The reflection grating can be positioned at a blaze angle optimized for maximum efficiency, and the folded optical path compensates for angular deviations, thereby improving measurement precision.
3Measurement precision
If a transmission grating with high line density is used to improve resolution, then spectral resolution increases, but thermal issues arise due to absorption of light energy
Solution Approach 1:
The patent substitutes the transmission grating with a reflection grating, fundamentally changing how light interacts with the dispersive element. Instead of light passing through and being absorbed by the grating lines (causing thermal issues), the reflection grating disperses light through surface reflection, significantly reducing energy absorption and thermal problems while maintaining or improving spectral resolution capability.
4Ease of operation
If the optical components are arranged in a linear configuration, then the alignment is simpler to establish, but the field of view is limited and scanning time increases
Solution Approach 1:
The patent employs a folded optical path that expands the effective field of view by redirecting light through multiple reflections and refractions in a compact space. This dimensional transformation allows a wider angular range of incoming light to be captured and directed to the detector, increasing the field of view and enabling faster scanning speeds without compromising alignment simplicity, as the folded geometry can be pre-configured and rigidly mounted.
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
Achieves a compact, high-resolution hyperspectral imaging apparatus with fast scanning times and improved signal-to-noise ratio, suitable for photoluminescence sample detection.
Implementation Method 1
The plurality of optical components including a diffraction element and a deflection mirror are arranged in a single optical plane
Implementation Method 2
The deflection mirror is arranged to deflect a diffracted light signal from the diffraction element out of the optical plane into a detector positioned above or below the optical plane
Implementation Method 3
incorporating a dichroic filter for improved signal deflection and compact fore-optics
Data Source
AI summary
A compact photoluminescence hyperspectral imaging apparatus comprises a fore-optics module and a spectrometer module. The fore-optics module has a line laser for line scanning a sample. The fore-optics module comprises optical components forming an emission light signal pathway to guide a line scan emission light signal from the sample into the spectrometer module. The spectrometer module comprises a plurality of optical components forming a folded optical light signal pathway between an emission light signal entrance and a deflection mirror. The plurality of optical components including a diffraction element and the deflection mirror are arranged in a single optical plane. The deflection mirror is arranged to deflect a diffracted light signal from the diffraction element out of the optical plane into a detector positioned above or below the optical plane.