Optical effect structures
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Solution Overview
Problem
Existing optical coating structures struggle to maintain a consistent color appearance over a broad range of viewing angles while minimizing iridescence, and are often complex and costly to produce.
Innovation Solution
An optical coating structure comprising a base layer with profile elements of 5 to 500 µm in size, arranged in a non-periodic manner, and a multilayer reflector that conforms to the surface profile, reducing diffraction effects and maintaining color consistency across angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multilayer reflector is used to impart structural color, then the color brightness and saturation are improved, but the color changes with viewing angle (iridescence) worsens
Solution Approach 1:
The base layer is segmented into multiple profile elements (protrusions or recesses) with different orientations. Each profile element reflects light at different angles, and when combined in a non-periodic arrangement, they collectively reflect light across a broad range of viewing angles, maintaining color consistency and reducing iridescence while preserving color brightness.
Solution Approach 2:
The profile elements are arranged in a non-periodic, asymmetric pattern rather than a regular periodic structure. This asymmetric arrangement disrupts the diffraction effects that cause strong iridescence in periodic structures, allowing the multilayer reflector to maintain consistent color appearance across broad viewing angles while preserving color saturation.
2Ease of manufacture
If profile elements are arranged in a periodic manner, then the manufacturing process is simplified, but diffraction effects increase causing stronger iridescence
Solution Approach 1:
The patent employs a non-periodic, asymmetric arrangement of profile elements that eliminates the regular diffraction patterns produced by periodic structures. This asymmetric configuration suppresses harmful diffraction effects and reduces iridescence while still allowing for relatively simple manufacturing through molding or etching processes.
3Object-generated harmful factors
If the profile elements are made smaller to reduce diffraction, then the iridescence is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the size parameters of profile elements within a specific range (10-100 micrometers) and controls their aspect ratio to balance optical performance and manufacturability. This parameter optimization reduces diffraction effects and iridescence while maintaining feasible manufacturing precision requirements through standard molding or etching processes.
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 provides a bright, consistent color appearance with minimal iridescence, is easier and cheaper to manufacture, and maintains a rich, luxurious matte effect without fading over time.
Implementation Method 1
a multilayer reflector on the base layer to impart the colour
Implementation Method 2
a quarter-wave stack reflector is a well-known building block of optical thin-film products. Such a stack generally comprises alternating layers of two or more dielectric materials with different refractive indexes
Implementation Method 3
the profile elements are configured to avoid diffraction effects
Implementation Method 4
The visual effects produced by this device are, at least in part, caused by diffraction effects caused by the crevices formed in the top layer
Data Source
Figure 1A~3
Figure 4~6
Figure 7A~7D
AI summary
An optical coating structure is provided that when applied to a surface of an object to imparts a colour to the object, the optical coating structure comprising: a base layer; a reflector on the base layer; and profile elements on the base layer under the reflector, the profile elements having a width and length which are each in the range of 5 to 500 µm in size, and being arranged in non-periodic manner or a periodic manner. The reflector may be a multilayer structure of alternating dielectric materials. A method of forming the optical coating structure is also provided.