Miniature NIR Spectrometer Wedged Window Asymmetry
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Solution Overview
Problem
Spectrometer devices face challenges in detecting spectral information efficiently, particularly at large angles, leading to low detection light intensity and reduced signal-to-noise ratio, especially for Lambertian objects.
Innovation Solution
The spectrometer device incorporates a spectrometer window with tilted outer and inner surfaces, allowing for the separation of angular distributions of illumination and detection light, and includes a light emitting element and detector configured to improve light collection and signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the spectrometer device uses a limited height design, then the device size is reduced, but the optical path requires light collection under large angles which causes Fresnel specular reflections and reduces detection efficiency
Solution Approach 1:
The patent applies asymmetry by tilting the outer and inner surfaces of the spectrometer window at different angles relative to the optical axis. The outer surface is tilted at a first angle and the inner surface at a second angle, creating an asymmetric wedge configuration. This asymmetric design separates the angular distributions of illumination and detection light, allowing the device to maintain a limited height while reducing Fresnel reflections and improving detection efficiency by collecting light at more favorable angles.
2Adaptability or versatility
If the spectrometer device collects light at large angles, then the field of view is increased, but the signal-to-noise ratio is reduced due to low reflected detection light intensity
Solution Approach 1:
The patent applies local quality by creating different optical paths for illumination light and detection light through the tilted window surfaces. The wedge configuration causes illumination light to enter at one angle while detection light exits at a different angle, locally optimizing the optical path for each function. This separates the angular distributions, allowing the device to maintain an extended field of view while improving the signal-to-noise ratio by collecting detection light at angles where the reflected intensity is higher.
3Reliability
If the spectrometer device uses a wedge-shaped window with tilted surfaces, then Fresnel reflections are reduced and detection efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent merges the window function with the optical path management function by integrating the tilted outer and inner surfaces directly into the spectrometer window structure. Rather than adding separate optical elements like prisms or mirrors, the wedge-shaped window itself performs the function of separating illumination and detection light angular distributions. This merging approach reduces device complexity by eliminating additional components while still achieving improved detection efficiency through reduced Fresnel reflections.
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 configuration enhances the detection efficiency, improves the signal-to-noise ratio, decreases light collection at large angles, increases dynamic range, and improves spectral contrast and reduces stray light.
Implementation Method 1
the detection light and the illumination light are transmitted through the spectrometer window, wherein spectrometer window comprises an outer surface that is facing the outside of the spectrometer device; wherein the spectrometer window further comprises an inner surface that facing the inside of the spectrometer device, wherein the outer surface is opposite of the inner surface, wherein a normal of the outer surface and a normal of the inner surface are tilted, particularly to each other
Implementation Method 2
In order to avoid Fresnel specular reflections, the maximum extend of the angular distribution of the illumination light on the sample interface may provide a lower limit on the collection of light from the sample interface
Data Source
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AI summary
The present invention relates to a spectrometer device (130) for obtaining at least one item of spectral information on at least one object (110) by spectral measurement, wherein the spectrometer device (130) comprises: (1) at least one sample interface (132), wherein the sample interface (132) defines a measurement surface, wherein the measurement surface is configured for defining a measurement pose of the object (110), particularly during the spectral measurement; (2) at least one light emitting element (138), wherein the light emitting element (138) is configured for emitting illumination light (140) for illuminating the at least one object (110) in order to generate detection light (142) from the at least one object (110); (3) at least one detector (144), wherein the detector (144) is configured for generating at least one detector (144) signal when receiving the detection light (142) from the object (110) in order to acquire the item of spectral information; (4) at least one spectrometer window (130), wherein the detection light (142) and the illumination are is transmitted through the spectrometer window (130), wherein spectrometer window (130) comprises an outer surface (148) that is facing the outside of the spectrometer device (130); wherein the spectrometer window (130) further comprises an inner surface (150) that facing the inside of the spectrometer device (130), wherein the outer surface (148) is opposite of the inner surface (150), wherein a normal of the outer surface (148) and a normal of the inner surface (150) are tilted.