Multi-layer Light Diffusing Coatings for Backlit Systems

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Solution Overview

Problem

Current backlit systems for consumer electronic devices require significant energy to transmit light through coating layers, limiting color and appearance options.

Innovation Solution

A multi-layer coating system comprising a first light diffusing basecoat with a film-forming resin, crosslinked organic particles, and inorganic pigment particles, and a second coating layer with reflective and/or translucent particles, where each layer's refractive index differs from the resin, allowing for efficient light transmission and reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional coating layers are used to transmit light in backlit systems, then light transmission is achieved, but energy consumption increases significantly

Engineering Contradiction:
Improveenergy consumptionVSAvoidlight transmission
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The coating system is divided into multiple functional layers: a first coating layer with light-diffusing particles for scattering and reflecting light, and a second coating layer with different refractive index particles for additional light management. This segmentation allows each layer to perform specific optical functions efficiently, reducing overall energy consumption while maintaining light transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite coating compositions combining organic resin binders with inorganic particles having different refractive indices (e.g., titanium dioxide, zinc oxide, barium sulfate). These composite materials create optimized light interaction pathways that enhance light transmission efficiency while reducing the energy required to drive light through the coating layers.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If conventional coating layers are used in backlit systems, then light transmission is achieved, but color and appearance options are limited

Engineering Contradiction:
Improvecolor and appearance optionsVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

Different regions of the coating system can use different particle compositions and concentrations. The first coating layer can be optimized for light diffusion with specific particle types, while the second coating layer can vary particle composition to achieve different optical effects. This allows diverse color and appearance options across different keys or regions without increasing overall energy consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention enables color variation through different combinations of inorganic particles with varying refractive indices and optical properties. By selecting specific particle types and concentrations in different coating layers, a wide range of colors and appearances can be achieved while maintaining energy efficiency through the optimized light management architecture.

Inventive Principle:
Principle #32Color changes

3Illumination intensity

If coating layers with varying refractive indices are used, then light diffusion and reflection are enhanced, but coating complexity increases

Engineering Contradiction:
Improvelight diffusion and reflectionVSAvoidcoating structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The complex optical functionality is segmented into two distinct coating layers, each with specific particle compositions. The first layer handles primary light diffusion, while the second layer provides additional reflection and refinement. This segmentation makes the complex system more manageable and manufacturable compared to a single-layer system with equally complex requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention manages complexity by systematically varying key parameters: each coating layer uses particles with specifically selected refractive indices relative to the resin binder. This parameter-based approach (controlling refractive index differences) provides a clear design framework that simplifies the development and manufacturing process despite the enhanced optical performance.

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 multi-layer coating achieves good hiding with significant light diffusion and transmittance, reducing energy consumption while enhancing visual appearance and functionality.

Implementation Method 1

The crosslinked organic particles and the inorganic pigment particles can each have a refractive index that is different from the refractive index of the film forming resin

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentUS11286396B2Light diffusing and reflective coatings
Publication Date: 2022.03.29 PPG COATINGS TIANJIN

AI summary

A multi-layer coating that transmits and reflects light can include a first coating layer and a second coating layer applied over the first coating layer. The first coating layer is prepared from a coating composition that includes a film forming resin, crosslinked organic particles, and inorganic pigment particles. The crosslinked organic particles and the inorganic pigment particles each have a refractive index that is different from the refractive index of the film forming resin. The second coating layer is prepared from a coating composition that includes a film forming resin and reflective and/or translucent particles.