Large Spot Size Spectrometer with Segmented Illumination
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Solution Overview
Problem
Miniaturized near-infrared (NIR) spectrometers have limited optical spot sizes, which can lead to measurement errors and low diffuse reflected power when dealing with inhomogeneous samples due to their small diameter, typically less than 3 mm, especially when trying to measure materials with irregular shapes and non-uniform packing.
Innovation Solution
The development of an optical device with a micro-electro-mechanical system (MEMS) based Fourier Transform infrared (FTIR) spectrometer that increases the optical spot size to between 3 mm and 20 mm by using a plastic molded part with miniaturized filament-based incandescent lamps and reflective optics, along with an aperture to filter unusable light and maximize coupling efficiency, allowing for larger sample illumination and improved light collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If miniaturized spectrometers are used, then device size is reduced, but optical spot size becomes limited (smaller than 3 mm)
Solution Approach 1:
The illumination system is segmented into multiple filament-based incandescent lamps arranged in a specific configuration, each contributing to different regions of the expanded spot size, allowing the miniaturized spectrometer to achieve larger effective illumination area through distributed light sources
Solution Approach 2:
The patent transitions from a single-point illumination model to a multi-dimensional illumination pattern by positioning multiple lamps at different spatial locations and angles, effectively expanding the optical spot size in multiple dimensions while maintaining compact device form factor
2Device complexity
If small spot size is used, then device complexity is reduced, but measurement precision deteriorates for inhomogeneous samples
Solution Approach 1:
The aperture is designed with specific geometric characteristics (shape and diameter) that create selective spatial filtering, allowing different regions of the scattered light to be differentially processed - useful sample information is passed while unusable light is filtered, enhancing measurement precision for inhomogeneous samples without adding complex processing systems
3Measurement precision
If spot size is increased to 3-20 mm, then measurement precision for inhomogeneous samples is improved, but device complexity increases
Solution Approach 1:
Multiple functional components (lamps, reflectors, aperture, optical coupling element) are merged into a single integrated optical head assembly, simplifying the overall system architecture while achieving the desired large spot size capability for improved measurement precision on inhomogeneous samples
Solution Approach 2:
The optical head design serves multiple functions simultaneously: illumination generation, light direction, spatial filtering, and optical coupling, all within a single integrated structure that achieves large spot size without proportionally increasing device complexity
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 solution enables more accurate and efficient measurement of inhomogeneous samples by increasing the spot size, reducing measurement errors, and enhancing the coupling efficiency of scattered light, thereby improving the spectral analysis of materials with varying scattering and absorption properties.
Implementation Method 1
a plurality of miniaturized filament-based incandescent lamps
Implementation Method 2
reflective optics (e.g., reflectors) surrounding the lamps
Data Source
AI summary
Aspects relate to an optical device providing a large spot size spectrometer. The optical device includes an optical head, an optical window, and a spectrometer. The optical head includes a plastic molded part having an aperture and a plurality of reflectors around the aperture formed therein. Each reflector may include a respective lamp assembled therein. The optical window is configured to receive a sample, to pass input light from the lamps to the sample and to pass scattered light from the sample towards the aperture. The aperture is configured to filter a first portion of scattered light containing unusable sample information and to pass a second portion of the scattered light to the spectrometer.