Dielectric-Metal Optical Filter for Low Angle Shift Transmission
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Solution Overview
Problem
Existing optical filters, particularly all-dielectric filters, suffer from significant angle shifts and reduced transmissivity at varying angles of incidence, leading to poor filter performance and inaccurate data capture by sensor elements.
Innovation Solution
A mixed dielectric/metal optical filter design is introduced, comprising alternating layers of high-index and low-index dielectric materials with strategically placed metal layers, such as niobium titanium oxide, zinc oxide, and silver, to minimize angle shifts and enhance transmissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all-dielectric filter design is used, then manufacturing simplicity is improved, but angle shift and transmissivity performance deteriorate at varying angles of incidence
Solution Approach 1:
The patent employs a composite filter structure combining dielectric materials (such as silicon dioxide and niobium titanium oxide) with metal materials (such as silver). This composite approach allows the filter to maintain manufacturing feasibility while achieving reduced angle shifts and improved transmissivity at varying angles of incidence, directly resolving the contradiction between manufacturing simplicity and performance consistency.
2Device complexity
If traditional optical filter design is used, then device complexity is reduced, but measurement precision deteriorates due to angle shifts
Solution Approach 1:
The patent modifies key optical parameters by introducing metal layers with specific refractive indices and absorption characteristics into the filter stack. These parameter changes enable the filter to maintain accurate spectral transmission characteristics at varying angles of incidence, thereby improving sensor measurement precision without requiring overly complex device architecture.
3Ease of manufacture
If simple filter structure is used, then ease of manufacture is improved, but transmissivity at varying angles of incidence deteriorates
Solution Approach 1:
The patent introduces metal layers as intermediary elements between dielectric layers in the filter stack. These metal intermediary layers serve dual functions: they maintain the relatively simple overall filter structure for ease of manufacture while simultaneously improving light transmissivity at varying angles of incidence by controlling electromagnetic wave interaction through their unique optical properties.
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 mixed dielectric/metal filter achieves reduced angle shifts and improved transmissivity, enhancing the accuracy of data captured by sensor elements, particularly at varying angles of incidence.
Implementation Method 1
The optical filter may include a first group of layers. The first group of layers may include alternating layers of a first dielectric material, of a group of dielectric materials, and a second dielectric material of the group of dielectric materials
Implementation Method 2
The filter may include a passband associated with a first spectral range of light that is passed to the sensor element. The filter may be associated with blocking a second spectral range of light from being passed to the sensor element
Data Source
AI summary
An optical filter may include a first group of layers. The first group of layers may include alternating layers of a first dielectric material, of a group of dielectric materials, and a second dielectric material of the group of dielectric materials. The optical filter may include a second group of layers. The second group of layers may include alternating layers of a third dielectric material, of the group of dielectric materials, and a fourth dielectric material of the group of dielectric materials. The optical filter may include a third group of layers. The third group of layers may include alternating layers of a fifth dielectric material, of the group of dielectric materials, a sixth dielectric material, of the group of dielectric materials, and a metal material. The third group of layers may be disposed between the first group of layers and the second group of layers.