ENZ Multi-Band Optical Filter Design for Thin Profile
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Solution Overview
Problem
Conventional band pass filters are thick, complex to design, and unsuitable for small devices due to their large thickness and precise layer control requirements, making it difficult to manufacture multi-band pass filters with high performance and thin profiles.
Innovation Solution
The development of multi-band pass filters using epsilon-near-zero (ENZ) material layers with distinct resonance frequencies and thicknesses, combined with an aperture-defining layer, allowing for a thin, sub-wavelength thickness and easy design, enabling the transmission of multiple wavelength bands through the application of an 'addition rule' for transmittance wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional band pass filters use a large number of relatively thick dielectric layers, then high transmittance performance can be achieved, but the filter thickness becomes several tens of millimeters which is unsuitable for small and thin handheld devices
Solution Approach 1:
The patent changes the fundamental parameters of the filter structure by using epsilon-near-zero (ENZ) material layers with specific thicknesses (10-1000 nm, much thinner than conventional layers) and designing a sub-wavelength thin overall structure (sum of filter layer and aperture-defining layer thickness less than incident light wavelength). This parameter change enables achieving high transmittance performance with dramatically reduced thickness compared to conventional band pass filters.
Solution Approach 2:
The patent employs composite material structures by combining multiple different ENZ material layers with distinct resonance frequencies, each layer contributing to different wavelength regions. This composite approach allows the thin filter to achieve multi-band pass characteristics while maintaining high transmittance performance, resolving the contradiction between thinness and performance.
2Reliability
If conventional band pass filters use precisely controlled thicknesses and number of stacked layers, then high transmittance performance can be secured, but the design becomes difficult and complex requiring independent design process for each target transmittance wavelength
Solution Approach 1:
The patent simplifies design by changing to a parameter-based design approach where each ENZ material layer is characterized by its resonance frequency and thickness. The 'addition rule' for transmittance wavelengths provides a systematic method to design multi-band filters by combining layers with different resonance frequencies, eliminating the need for complex independent design processes for each wavelength target.
Solution Approach 2:
The patent creates a universal design framework that can be applied across multiple wavelength bands. The same basic structure (filter layer with multiple ENZ material layers and aperture-defining layer) serves as a universal template for designing filters at different wavelengths by simply adjusting layer thicknesses and materials according to their resonance frequencies, rather than requiring separate design methodologies.
3Reliability
If conventional band pass filters are designed for specific wavelength targets, then high transmittance can be achieved at those wavelengths, but it becomes difficult to manufacture multi-band pass filters
Solution Approach 1:
The patent achieves multi-band capability through composite material layers with different resonance frequencies. Each ENZ material layer is designed to resonate at a specific frequency, and by stacking layers with different resonance frequencies, the filter can pass multiple wavelength bands simultaneously. The 'addition rule' systematically combines these layers to achieve desired multi-band transmittance characteristics.
Solution Approach 2:
The patent segments the filter design into independent ENZ material layers, each responsible for a specific wavelength region. This segmentation allows each layer to be optimized for its specific resonance frequency while the overall filter achieves multi-band performance through the combination of segments, making multi-band filter manufacturing feasible and systematic.
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 solution results in high-performance, thin multi-band pass filters that can be easily designed and manufactured, suitable for small devices, with enhanced transmittance characteristics and reduced thickness, achieving efficient light transmission across multiple wavelength bands.
Implementation Method 1
The plurality of ENZ material layers may have resonance frequencies different from each other... the first material layer may have a first resonance frequency, and the second material layer may have a second resonance frequency which is greater than the first resonance frequency
Implementation Method 2
an aperture-defining layer that is disposed on the filter layer and comprises at least one aperture, wherein the filter layer is exposed to incident light through the at least one aperture
Implementation Method 3
a band pass filter may be manufactured by alternately stacking a dielectric layer having a high refractive index and a dielectric layer having a low refractive index in a repeated manner
Data Source
AI summary
A multi-band pass filter may include a filter layer including a plurality of different epsilon-near-zero (ENZ) material layers that are sequentially arranged; and an aperture-defining layer that is disposed on the filter layer and comprises at least one aperture. The filter layer may be exposed to incident light through the at least one aperture, and may be configured to pass a plurality of wavelength regions of the incident light.