Multimodal Particle Coating for Uniform Matte Appearance

Solution Overview

Problem

Current matte surface technologies fail to provide a uniform matte appearance across a wide range of incident light angles, particularly at grazing angles, and are not robust or cost-effective for both planar and complex three-dimensional objects.

Innovation Solution

A low-specular-reflectance surface is achieved using a coating with a multimodal particle size distribution of substantially spherical particles, where the distribution has two or more modes with specific peak sizes and mode width parameters, resulting in a surface with low gloss and reduced specular reflectance across various angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a bimodal distribution of particles with small particles (diameter < 2 microns) and large particles (diameter 8-50 microns) is used, then uniform matte appearance is achieved for angles in the range of 60-85°, but specular reflections at grazing angles (greater than 85°) are not suppressed

Engineering Contradiction:

Improvespecular reflectanceVSAvoidangular independence

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The particle size distribution is segmented into multiple distinct modes (typically 3-5 modes) with specific diameter ranges. Each mode contributes to suppressing specular reflections at different incidence angles, collectively achieving broad angular coverage. The segmentation of particle sizes allows systematic control of optical properties across the full angular range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the particle size distribution parameters by specifying multiple modes with defined diameter ranges and relative proportions. This parameter optimization ensures that particles of different sizes work together to scatter light effectively across all incidence angles, resolving the angular dependence issue.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If smaller particles with diameter between 0.04-0.2 microns are used, then absorption and irregular surface reflection at angles of 60° are improved, but the results cannot be extrapolated beyond this specific angle range

Engineering Contradiction:

Improvematte appearance uniformityVSAvoidangular range coverage

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The coating comprises a composite particle system with multiple size modes (typically 3-5 distinct modes) where each particle size category contributes different optical functions. This composite structure enables the coating to maintain matte appearance across the full angular range by combining the scattering effects of particles with different diameters.

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If conventional matte surface solutions are used, then specular reflections at moderate angles are reduced, but grazing angle reflections (greater than 80°) remain intense

Engineering Contradiction:

Improvespecular reflectionVSAvoidperformance consistency

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The particle size distribution is segmented into multiple distinct modes (typically 3-5 modes) with specific diameter ranges. Each mode contributes to suppressing specular reflections at different incidence angles, collectively achieving broad angular coverage. The segmentation of particle sizes allows systematic control of optical properties across the full angular range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the particle size distribution parameters by specifying multiple modes with defined diameter ranges and relative proportions. This parameter optimization ensures that particles of different sizes work together to scatter light effectively across all incidence angles, resolving the angular dependence issue.

Inventive Principle:

Principle #35Parameter changes

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 uniform matte appearance and increased onset angle for grazing-incidence specular reflectance, reducing intense reflections, and is applicable to both planar and complex surfaces, while being cost-effective and robust.

Implementation Method 1

A low-specular-reflectance surface is achieved using a coating with a multimodal particle size distribution of substantially spherical particles... resulting in a surface with low gloss and reduced specular reflectance across various angles

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS11118070B2Low specular reflectance surface

Publication Date: 2021.09.14 EASTMAN KODAK CO

AI summary

A low-specular-reflectance surface, includes a coating on a surface, wherein the coating includes a plurality of substantially spherical particles having a multimodal particle size distribution, wherein the particles protrude from a top surface of the coating to provide substantially spherical caps. The multimodal particle size distribution has two or more modes, each mode having a peak defining an associated mode particle size, wherein the distribution function includes a first mode having a first peak corresponding to a first particle size and a second mode having a second peak corresponding to a second particle size. A ratio of the second particle size to the first particle size is between 1.7-4.0. A smallest of the mode particle sizes is greater than or equal to 1.0 microns, and a largest of the mode particle sizes is greater than or equal to 3.0 microns.