High-Refractive-Index Polymer Diffraction Light Guide Plates for Low Haze

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Solution Overview

Problem

Existing lenses for virtual and augmented reality devices face issues with high refractive index materials like glass being heavy and unsafe, while high refractive index plastics lack surface flatness, thickness uniformity, and mechanical strength, leading to problems like haze and poor interfacial adhesion.

Innovation Solution

A diffraction light guide plate with an integrated diffraction lattice pattern on its surface, composed of a continuous phase polymer containing episulfide, thiol, and aromatic cyclic compounds, ensuring minimal refractive index difference and excellent mechanical properties, manufactured through a one-step process using buffer spacers to maintain uniformity and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass with high refractive index is used for lenses, then light transmission and refractive index are improved, but weight increases and safety deteriorates due to breakage risk

Engineering Contradiction:

Improvelight transmissionVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material parameters by using high refractive index plastic (refractive index 1.6 or higher) instead of glass, achieving similar optical performance with reduced weight and improved safety. The plastic material maintains high light transmission while being lighter and less prone to breakage.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structures including the plastic lens with integrated diffraction lattice pattern, combining optical functionality with structural material to achieve both high refractive index and lightweight properties simultaneously.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If high refractive index plastic is used to replace glass, then weight is reduced and safety is improved, but surface flatness and thickness uniformity deteriorate

Engineering Contradiction:

ImproveweightVSAvoidsurface flatness

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent merges the lens substrate and diffraction lattice pattern into a single integrated structure made of the same high refractive index plastic material, eliminating interface issues and improving surface flatness and thickness uniformity through one-step molding.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The diffraction lattice pattern is formed during the initial molding process before final lens fabrication, ensuring surface flatness and thickness uniformity are established early in manufacturing and maintained throughout subsequent processing.

Inventive Principle:

Principle #10Preliminary action

3Weight of moving object

If high refractive index plastic is used, then weight is reduced, but mechanical strength and interfacial adhesion deteriorate leading to poor pencil hardness

Engineering Contradiction:

ImproveweightVSAvoidmechanical strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent combines the lens material and diffraction lattice pattern into a single integrated high refractive index plastic structure, eliminating weak interfaces and improving overall mechanical strength and pencil hardness through unified material properties.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If inorganic particles are used in large quantities to achieve high refractive index, then refractive index is improved, but haze increases

Engineering Contradiction:

Improverefractive indexVSAvoidhaze

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes from using inorganic particles to using organic high refractive index plastic materials, achieving high refractive index (1.6 or higher) without the scattering and haze problems associated with particle-based solutions.

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 lightweight, high refractive index lens with improved mechanical properties, reduced haze, and enhanced light efficiency, enabling high-resolution, high-luminance images for virtual and augmented reality devices.

Implementation Method 1

the optical layer having diffraction lattice pattern formed on one surface is a continuous phase of polymer comprising an episulfide compound, a thiol compound, and an aromatic cyclic compound having two or more hydroxyl groups

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

diffraction light guide plate

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

diffraction lattice pattern

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS12441843B2Diffraction light guide plate and manufacturing method thereof

Publication Date: 2025.10.14 LG CHEM LTD

AI summary

A diffraction light guide plate comprising an optical layer having diffraction lattice pattern formed as an integrated structure without an interface on one surface thereof, where the optical layer having diffraction lattice pattern is a continuous phase of polymer comprising an episulfide compound, a thiol compound, and an aromatic cyclic compound having two or more hydroxyl groups, the diffraction light guide plate having excellent thickness uniformity and flatness as well as low haze and excellent visibility, and excellent mechanical properties such as pencil hardness and strength, and a method for manufacturing the diffraction light guide plate.