Structural Color Oxide Film for Durable Angle-Dependent Color
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Solution Overview
Problem
Existing chromatic color members prone to peeling and fading due to paint deterioration, and there is a desire for structurally colored materials that exhibit different color tones based on viewing angle.
Innovation Solution
A structurally colored material with a substrate and an oxide film comprising a porous and dense layer, where the oxide film thickness varies between 150 nm and 1000 nm, and 0.75 to 1.25 times the mean thickness, formed through anodizing a metal film on the substrate with specific voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If paint is used to impart chromatic color tones to member surfaces, then color characteristics are enhanced, but the paint film is prone to peeling, fading, and deterioration due to organic matter degradation
Solution Approach 1:
The invention changes the fundamental mechanism from chemical coloration (paint) to physical optical interference (oxide film thickness control). By controlling oxide film thickness parameters (50-200 nm for interference colors, 150-1000 nm for structural colors), the patent achieves color imparting without organic matter, eliminating paint deterioration while maintaining color characteristics.
Solution Approach 2:
The invention replaces the chemical/organic paint system with a physical inorganic oxide film system. The color is generated through optical interference effects in the oxide film rather than through pigments or dyes, substituting a physically stable system for a chemically unstable one, thereby achieving both color enhancement and improved durability.
2Ease of manufacture
If a single-layer oxide film is formed on the substrate, then the manufacturing process is simple, but the film thickness varies significantly across the surface leading to poor color uniformity
Solution Approach 1:
The invention divides the oxide film into two distinct layers: a first oxide film layer formed directly on the substrate, and a second oxide film layer formed on top of the first layer. This segmentation allows each layer to serve different functions - the first layer provides a base with controlled thickness, while the second layer enhances color saturation and uniformity, thereby achieving both manufacturing simplicity and precise thickness control.
Solution Approach 2:
The invention creates a composite oxide film structure consisting of two oxide layers with different thicknesses and potentially different compositions. This composite structure combines the advantages of each layer - the first layer ensures good adhesion and base thickness control, while the second layer provides enhanced optical interference effects and color uniformity, achieving both ease of manufacture and manufacturing precision.
3Productivity
If conventional anodizing is performed without voltage control, then the process is fast and simple, but the oxide film thickness varies significantly (greater than 25% variation) compromising color consistency
Solution Approach 1:
The invention implements voltage control during the anodizing process to regulate oxide film formation. By monitoring and controlling the applied voltage within specific ranges (0-50 V for the first layer, 50-200 V for the second layer), the process ensures consistent current density and oxidation rate, thereby achieving both high productivity and precise thickness control with variation of 25% or less.
Solution Approach 2:
The invention employs a two-stage anodizing process with distinct voltage parameters for each stage. The first stage uses lower voltage (0-50 V) to form a base layer, followed by a second stage with higher voltage (50-200 V) to form the color-enhancing layer. This periodic action with controlled parameters ensures consistent thickness and excellent color uniformity while maintaining efficient production speed.
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 material exhibits durable structural color with varying chromatic tones based on viewing angle and maintains optical characteristics over time.
Implementation Method 1
a technique has been proposed that uses optical interference to impart chromatic color tones to the surface of members
Implementation Method 2
the oxide film is formed on the substrate by performing an anodizing treatment on the metal film
Implementation Method 3
a metal film is formed on the substrate by sputtering
Data Source
Figure 1~2
Figure 3
AI summary
A structurally colored material (1) includes a substrate (2) and an oxide film (3), which is composed of a metal oxide and which covers the substrate (2). The oxide film (3) includes a porous layer (31), which contains a plurality of pores (311), and which is disposed on the substrate (2), and a dense layer (32), which does not contain pores (311) and which is layered on the porous layer (31). When the thickness of the oxide film (3) is measured at various locations, the thickness of the oxide film (3) at each measurement location is within the range of 150 nm or more and 1000 nm or less and within the range of 0.75 times or more and 1.25 times or less with respect to the mean value of the thickness of the oxide film (3).