Color-Developing Structure with Laminated Film for Multi-Hued Reflection
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Solution Overview
Problem
Existing color developing members struggle to achieve multi-hued colors through a simple process, with proposed solutions either requiring numerous layers to achieve intense reflection or experiencing abrupt color changes with observation angle.
Innovation Solution
A color developing structure featuring a concavo-convex surface with overlapping structures for light dispersion and diffraction effects, utilizing a laminated film with layers of different refractive indices to achieve multi-hued colors through a single process, where the wavelength band is determined by the line width and array pitches of convexities, and the refractive index and film thickness of the laminated film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multilayer structure made of polymer materials is used for structural color development, then the structure can be formed, but it requires a large number of layers to achieve intense reflection, increasing production cost
Solution Approach 1:
The patent changes the refractive index parameter by using inorganic dielectric materials with high refractive index differences (e.g., TiO2 with n=2.6 and SiO2 with n=1.46) instead of polymer materials. This parameter change allows achieving intense reflection with fewer layers, resolving the contradiction between reflection intensity and number of layers.
Solution Approach 2:
The patent employs composite material strategy by combining inorganic dielectric materials (TiO2, SiO2) in a multilayer structure. This composite approach leverages the high refractive index contrast between different inorganic materials to achieve strong optical reflection with reduced layer count, addressing the production cost issue.
2Illumination intensity
If a multilayer film interference structure is used, then intense reflection can be achieved, but the color change depending on observation angle becomes abrupt, making it difficult to express specific colors
Solution Approach 1:
The patent optimizes the film thickness parameters of each layer to control the interference conditions. By carefully selecting thickness values (e.g., quarter-wavelength thicknesses), the patent achieves intense reflection while moderating the angular dependence of color, allowing specific colors to be expressed accurately.
Solution Approach 2:
The patent applies different local qualities by varying the refractive index and thickness of individual layers within the multilayer structure. Each layer is designed with specific properties to contribute to the overall optical performance, enabling precise color control while maintaining intense reflection.
3Ease of manufacture
If polymer materials are used for the multilayer structure, then the structure can be formed, but the refractive index difference between adjoining layers is small, requiring more layers for intense reflection
Solution Approach 1:
The patent fundamentally changes the material parameter by switching from polymer materials to inorganic dielectric materials. This change enables large refractive index differences between layers (e.g., 1.26 difference between TiO2 and SiO2), which dramatically reduces the number of layers needed for intense reflection.
Solution Approach 2:
The patent uses composite inorganic dielectric materials (TiO2, SiO2, Nb2O5) that provide both high refractive index contrast and good manufacturability through conventional deposition techniques, resolving the contradiction between ease of manufacture and device complexity.
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 approach allows for the creation of multi-hued colors with moderate color change upon angle observation, preventing chroma and glossiness deterioration, while maintaining effective light reflection and dispersion.
Implementation Method 1
structural color development through diffraction and interference
Implementation Method 2
structural color development through diffraction and interference
Implementation Method 3
overlapping structures for light dispersion and diffraction effects
Implementation Method 4
the wavelength band is determined by the line width and array pitches of convexities
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A color developing structure capable of achieving multi-hued color through a simple process, and a method of producing the same are provided. In the color developing structure formed on a surface of a base material: the color developing structure has a rectangular shape in plan view, and is formed of a concavo-convex structure having a plurality of convexities with different heights and a laminated film including a plurality of layers laminated on the concavo-convex structure; the plurality of layers adjoining in a lamination direction are made of materials that transmit light of the same wavelength band and have different refractive indices with respect to light of the wavelength band; and the plurality of layers have the same thickness.