Wavelength Selection Filter Structure Without Precise Waveguide Control
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Solution Overview
Problem
Existing wavelength selection filters using guided-mode resonance face challenges in achieving high wavelength selectivity due to the need for precise control of the waveguide layer thickness, which increases manufacturing complexity and cost.
Innovation Solution
A wavelength selection filter is designed with a projection-depression structure layer, a high refractive index layer with specific thickness and area ratios, and a filling layer, allowing light to produce resonance in close wavelength ranges and enhancing the intensity of extracted light without precise control of the waveguide layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a waveguide layer is added to increase wavelength selectivity, then the wavelength selectivity for reflected light is improved, but the manufacturing precision requirement increases due to the need for precise thickness control
Solution Approach 1:
The patent extracts the waveguide layer from the structure, removing it entirely while maintaining wavelength selectivity through the substrate-projection system alone. This eliminates the manufacturing complexity associated with precise waveguide thickness control while preserving the essential wavelength selection function through optimized substrate and projection parameters
Solution Approach 2:
The patent segments the optical function into distinct components: the substrate provides the base refractive index and mechanical support, while the projections provide the diffraction and resonance control. This segmentation allows each component to be optimized independently, with the substrate thickness and projection dimensions being controlled rather than requiring precise waveguide layer thickness control
2Manufacturing precision
If the waveguide layer thickness is precisely controlled to achieve resonance, then the wavelength selectivity is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The waveguide layer is extracted from the structure, eliminating the need for its precise thickness control. The wavelength selectivity is achieved through the substrate and projection dimensions, which are more easily manufactured with standard tolerances, thereby improving ease of manufacture while maintaining optical performance
Solution Approach 2:
The patent changes the critical parameters from waveguide layer thickness to substrate thickness and projection dimensions. These parameter changes shift the control requirements to dimensions that are more readily manufacturable with conventional processes, improving ease of manufacture while achieving the same wavelength selection through different physical dimensions
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 proposed filter configuration increases the intensity of extracted light and enhances wavelength selectivity, simplifying the manufacturing process by eliminating the need for precise thickness control of the waveguide layer.
Implementation Method 1
A wavelength selection filter that uses guided-mode resonance is proposed as a filter for selecting light using an optical phenomenon caused by the microstructure of an object. When light is incident on the subwavelength grating, the diffracted light is less likely to emerge into the space from which the incident light is emitted. Meanwhile, for example, the refractive index difference between the subwavelength grating area and its surroundings causes light in a specific wavelength range to be multiply reflected while propagating. As a result, the light produces resonance and emerges as intense reflected light.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A wavelength selection filter includes a first high refractive index section with a thickness of T1, a second high refractive index section with a thickness of T2, a high refractive index layer made of a material with a refractive index of n1, a projection-depression structure layer made of a material with a refractive index of n2, a filling layer made of a material with a refractive index of n3, a first high refractive index section with an area ratio of R1, and a second high refractive index section with an area ratio of R2. With n1 > n2, n1 > n3, and R1 + R2 > 1, the value of T1 × {n1 × R1 + n2 × (1 - R1)} is a first parameter, the value of T2 × {n1 × R2 + n3 × (1 - R2)} is a second parameter, and the ratio of the second parameter to the first parameter is 0.7 or more and 1.3 or less.