Tunable Optical Filter with Segmented Dielectric Layers
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Solution Overview
Problem
Existing optical filters, such as Fabry-Perot wavelength-tunable interference filters, face challenges in achieving both a wide measurement wavelength range and high spectroscopic measurement accuracy, as dielectric multilayer films provide high wavelength resolution but a narrow measurement range, while metal alloy films offer a wide range but lower resolution and accuracy.
Innovation Solution
The optical filter design incorporates a pair of reflection films facing each other via a gap, with layered structures formed by alternate stacking of high- and low-refractive layers, where the optical film thicknesses are based on different design center wavelengths, and coupled by light-transmissive layers, allowing for a wider measurement wavelength range and high wavelength resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dielectric multilayer films are used as reflection films, then wavelength resolution is improved, but measurement wavelength range becomes narrower
Solution Approach 1:
The reflection films are divided into multiple layered structures, each with different design center wavelengths. This segmentation allows each layer to handle specific wavelength ranges while collectively covering a broader spectrum, resolving the contradiction between narrow range and high resolution
Solution Approach 2:
Different regions of the reflection films (different layered structures) are assigned different optical properties through varying design center wavelengths. This local differentiation enables high wavelength resolution at specific wavelengths while expanding the overall measurement range
2Adaptability or versatility
If metal alloy films or metal films are used as reflection films, then measurement wavelength range is widened, but wavelength resolution and spectroscopic measurement accuracy deteriorate
Solution Approach 1:
The invention uses composite layered structures combining multiple dielectric materials with different refractive indices. This composite approach maintains the high wavelength resolution of dielectric films while extending the measurement range, avoiding the limitations of metal films
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 design enables the optical filter to transmit light across a wide range from visible light to near-infrared, achieving high spectroscopic accuracy and resolution, with the ability to select specific peak wavelengths, thereby overcoming the limitations of previous technologies.
Implementation Method 1
the reflection film is formed by a plurality of layered structures, the plurality of layered structures are respectively formed by alternate stacking of high-refractive layers and low-refractive layers
Implementation Method 2
a pair of reflection films facing each other via a gap, and a gap change portion that changes a distance between the pair of reflection films
Data Source
AI summary
An optical filter includes a pair of reflection films facing each other via a gap, and a gap change portion that changes a distance between the pair of reflection films, wherein the reflection film is formed by a plurality of layered structures, the plurality of layered structures are respectively formed by alternate stacking of high-refractive layers and low-refractive layers having smaller refractive indices than the high-refractive layers and, in the respective layered structures, optical film thicknesses of the high-refractive layers and optical film thicknesses of the low-refractive layers are film thicknesses based on predetermined design center wavelengths set with respect to each of the layered structures, and the design center wavelengths are different with respect to each of the layered structures.