Diffractive Pigment Blend Neutral White Background

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Solution Overview

Problem

Existing achromatic diffractive pigment compositions using conventional metal-dielectric flakes provide a gray or black background color and iridescent diffractive effect, whereas all-dielectric diffractive pigment flakes struggle to achieve a neutral white background color and white diffractive effect, which is desirable for preserving underlying colors and exhibiting a rainbow effect at different viewing angles.

Innovation Solution

A diffractive pigment blend is created by mixing different types of all-dielectric diffractive pigment flakes with varying optical designs and diffraction structures, including multilayer and encapsulated structures, to achieve a combined neutral white background color and diffractive effect, utilizing dielectric materials like zinc sulfide, titanium dioxide, and silicon dioxide, and diffraction gratings with specific line frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional metal-dielectric pigment flakes are used, then the pigment composition provides a gray or black background color and iridescent diffractive effect, but it dulls or obscures the underlying color

Engineering Contradiction:
Improveavailability of conventional pigment solutionsVSAvoidobscuring of underlying color
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material composition parameter from metal-dielectric to all-dielectric layers, which fundamentally alters the optical properties. The all-dielectric structure with controlled layer thicknesses and refractive indices provides a white background color that does not obscure underlying colors, while still maintaining diffractive effects

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material structures with multiple dielectric layers of different refractive indices (e.g., TiO2, SiO2, ZnS) to achieve both the white background color and diffractive effects simultaneously, combining the benefits of different material properties in a layered composite structure

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If all-dielectric diffractive pigment flakes are used, then the pigment composition is substantially transparent and allows overprinting, but achieving a neutral white background color and white diffractive effect is difficult

Engineering Contradiction:
Improvetransparency and preservation of underlying colorVSAvoidcomplexity of optical design
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention systematically varies parameters including layer thicknesses (e.g., quarter-wave, half-wave, or other optical thicknesses), refractive indices of different dielectric materials, and the number of dielectric layer pairs to achieve the desired white background color and white diffractive effect while maintaining transparency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Different regions of the pigment flake structure have different optical properties - the dielectric layers are designed with specific local thicknesses and material compositions to provide both the white background color through thin-film interference and the white diffractive effect through the diffractive structure, with each layer optimized for its specific function

Inventive Principle:
Principle #3Local quality

3Device complexity

If a single type of all-dielectric diffractive pigment flake is used, then the optical design can be simplified, but achieving a combined neutral white diffractive effect is difficult

Engineering Contradiction:
Improvesimplicity of optical designVSAvoidachieving neutral white diffractive effect
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The invention segments the diffractive pigment into multiple flake types, each with a specific optical design centered at a particular design wavelength. By blending these segmented flake types, the invention achieves a combined neutral white diffractive effect that would be difficult to obtain from a single flake type, while each individual flake type maintains a relatively simple optical design

Inventive Principle:
Principle #1Segmentation

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 diffractive pigment blend provides a color-neutral background that preserves underlying colors and exhibits a white diffractive effect, showing all colors of the rainbow at different viewing angles, with a combined diffractive effect that is additive and neutral under both diffuse and direct illumination.

Implementation Method 1

Light incident on such a pigment flake is diffracted into its color components, i.e., angularly dispersed according to wavelength, by the diffractive structure, so that the pigment flake appears to have different colors at different viewing angles

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

As a result of thin-film interference, a particular color component of light incident on such a pigment flake is reflected by the dielectric layers and another color component is transmitted, so that the pigment flake appears to have a color referred to as a background color

Methodology Applied
Scientific EffectThin-film interference: Interference

Data Source

PatentEP3428236B1Diffractive pigment blend
Publication Date: 2023.11.29 VIAVI SOLUTIONS INC(US)
  • EP3428236B1 patent drawingFigure 1
  • EP3428236B1 patent drawingFigure 2A
  • EP3428236B1 patent drawingFigure 2B

AI summary

A diffractive pigment blend or composition is provided which includes a plurality of groups of all-dielectric diffractive pigment flakes. The pigment flakes of each group each include one or more dielectric layers for providing a background color, at least one of which includes a diffractive structure for providing a diffractive effect. Each group of pigment flakes provides a different diffractive effect, and the diffractive pigment blend or composition provides a combined diffractive effect that is a combination of the different diffractive effects. The combined diffractive effect may be a neutral white diffractive effect or may include a reversal in color travel.