Photonic Balls With Core-Shell Particles For Angle-Independent Color
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Solution Overview
Problem
Existing photonic materials that exhibit structural color often change color with viewing angle due to Bragg diffraction, whereas materials with angle-independent structural color, like the plum-throated cotinga's feathers, are less understood and underexploited, and current synthetic approaches to replicate such properties are limited.
Innovation Solution
A photonic droplet containing a microstructure of core-shell colloidal particles with short-range ordering, where the shell thickness and refractive index contrast control the scattering of light to produce angularly-independent structural color, allowing for the creation of colorful, flexible reflective displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ordered colloidal crystal structures are used to produce structural color, then the color is vivid and saturated, but the color varies with viewing angle due to Bragg diffraction
Solution Approach 1:
The patent introduces disordered regions locally within the colloidal crystal structure, creating pockets of isotropic scattering that suppress angle-dependent Bragg diffraction while preserving overall color saturation through controlled short-range order in other regions
Solution Approach 2:
The patent creates a composite photonic material combining ordered colloidal crystal regions (for color saturation) with disordered isotropic scattering regions (for angle independence), achieving both properties simultaneously in a single structured material
2Adaptability or versatility
If disordered colloidal structures are used to achieve angle-independent structural color, then the color is viewing-angle independent, but the color saturation and vividness are reduced
Solution Approach 1:
The patent introduces disordered regions locally within the colloidal crystal structure, creating pockets of isotropic scattering that suppress angle-dependent Bragg diffraction while preserving overall color saturation through controlled short-range order in other regions
Solution Approach 2:
The patent applies partial disordering rather than complete randomization, maintaining enough short-range order to preserve color saturation while introducing sufficient disorder to achieve angle independence, finding the optimal balance between the two opposing requirements
3Adaptability or versatility
If bidisperse particle mixtures are used to create amorphous colloidal structures, then angle-independent structural color is achieved, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the size distribution parameter of colloidal particles from monodisperse to bidisperse, enabling spontaneous amorphous packing that produces angle-independent structural color while utilizing self-assembly processes to minimize manufacturing complexity
Solution Approach 2:
The patent exploits the self-assembly behavior of bidisperse colloidal particles, which automatically form amorphous structures with appropriate short-range order when processed through standard deposition techniques, eliminating the need for complex external ordering fields or procedures
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 photonic droplet achieves angle-independent structural color, enabling the development of colorful reflective electronic displays without the need for filtering materials, leading to high efficiency and versatility in color production.
Implementation Method 1
light of specific wavelengths is selectively scattered from nanostructures with variations in index of refraction
Implementation Method 2
variations in index of refraction on length-scales of the order of visible light
Implementation Method 3
Structural color arises from constructive interference of light scattered by variations in the refractive index within a material
Implementation Method 4
A photonic droplet enclosing a microstructure of core-shell colloidal particles which, when subject to ambient light, exhibits angularly-independent structural color
Data Source
AI summary
A photonic assembly for observing a preselected color includes an assembly of colloidal particles in a continuous liquid phase, the colloidal particles comprising a core scattering center and a shell layer surrounding the core, wherein the core scattering center is selected to scatter light having a predetermined wavelength, and wherein the shell has a thickness selected to provide an overall colloidal particle size that is about the same dimension as the wavelength of preselected color to be observed.