Light Diffuser Core-Shell Particles Inhibit Backscattering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing light diffusers struggle to sufficiently inhibit backscattering due to a slight refractive index difference between particles and the transparent polymer, leading to incomplete suppression of light diffusion in the opposite direction.

Innovation Solution

A light diffuser is developed with transparent cross-linked resin particles dispersed in a compatible state within a transparent resin, where the refractive index difference between the particles and the resin is controlled between 0.15 to 0.4, and the resin infiltrates the outer perimeter of the particles to blur the interface, preventing backscattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If transparent particles with slight refractive index difference are dispersed in transparent polymer, then light diffusion in forward direction is achieved, but backscattering is not sufficiently inhibited

Engineering Contradiction:
Improveforward light diffusionVSAvoidbackscattering
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The invention applies local quality by creating a core-shell structure where the particle center and outer layer have different refractive indices. The core region maintains a refractive index difference for forward light diffusion, while the outer layer has a refractive index matching the transparent polymer to eliminate backscattering at the interface. This spatial differentiation of optical properties resolves the contradiction between achieving forward diffusion and preventing backscattering.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the refractive index parameter across the particle structure. By designing particles with a refractive index gradient (different indices in core vs. outer layer) and controlling the concentration of transparent particles in the polymer matrix, the invention optimizes both forward light diffusion and backscattering suppression. The refractive index of the outer layer is specifically matched to the polymer to prevent reflection.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If refractive index difference at interface is reduced to inhibit backscattering, then backscattering is suppressed, but light diffusion capability is weakened

Engineering Contradiction:
Improvebackscattering suppressionVSAvoidlight diffusion
Core Design Contradiction:
Object-generated harmful factorsVSIllumination intensity

Solution Approach 1:

The invention segments the particle into two functional regions: a core region with refractive index difference that provides light diffusion, and an outer layer with matched refractive index that suppresses backscattering. This segmentation allows each region to perform its specific function independently, resolving the contradiction between maintaining diffusion capability and reducing backscattering.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the particle are assigned different optical qualities. The core maintains high refractive index difference for diffusion, while the outer layer has refractive index matched to the polymer for backscattering suppression. This local differentiation enables simultaneous achievement of both objectives.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If transparent particles are dispersed in transparent resin, then light diffusion function is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvelight diffusion functionVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The core-shell particle structure is designed to be self-assembling through simple mixing and drying processes. The transparent particles with optimized refractive index properties automatically form the desired structure when dispersed in the polymer matrix, eliminating the need for complex multi-step manufacturing processes while achieving the light diffusion function.

Inventive Principle:
Principle #25Self-service

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 effectively inhibits backscattering by maintaining a refractive index gradient, enhancing light diffusion in the forward direction while allowing high productivity, low cost, and wide material options, suitable for various applications.

Implementation Method 1

A light-diffuser refracts light at an interface between a transparent material and a light diffusing agent by a refractive index difference therebetween and diffuses the refracted light forward.

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

Thus, light is partially reflected by the refractive index difference and also partially diffused in a direction opposite to the proceeding direction of light.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

the resin infiltrates the outer perimeter of the particles to blur the interface, preventing backscattering

Methodology Applied
Scientific EffectInterfacial blending:

Data Source

PatentEP3931608B1Light-diffuser, light diffusing adhesive, light diffusing hard coat member, light diffusion film, and image forming apparatus including light diffusion film
Publication Date: 2024.05.01 SAMSUNG ELECTRONICS CO LTD
  • EP3931608B1 patent drawingFigure 1A~2A
  • EP3931608B1 patent drawingFigure 2B~4
  • EP3931608B1 patent drawingFigure 5A~7B

AI summary

A light-diffuser includes a transparent resin and transparent particles dispersed in the transparent resin. The transparent resin has a refractive index different from that of the transparent particles, and at least one portion of an outer perimeter of each of the transparent particles, respectively, is made compatible with the transparent resin disposed in the vicinity of the transparent particles, respectively.