Optical Glass Composition for Thin Light Guide Plates

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Solution Overview

Problem

Current optical glasses used in light guide plates for head-mounted displays have insufficient light transmittance, particularly in the blue wavelength range, which limits their performance in augmented, virtual, and mixed reality applications.

Innovation Solution

An optical glass composition comprising SiO2, B2O3, La2O3, TiO2, and optional components like Y2O3, WO3, Nb2O5, ZrO2, and Gd2O3, optimized to achieve a high refractive index and high light transmittance, with specific ranges for each component to enhance strength, refractive index, and devitrification temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a high refractive index glass is used for light guide plate, then the thickness can be reduced and design flexibility is improved, but the light transmittance becomes insufficient

Engineering Contradiction:
Improvethickness of light guide plateVSAvoidlight transmittance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the glass by precisely controlling the content ranges of specific oxides (SiO2: 9.0-11.0%, B2O3: 22.0-24.0%, La2O3: 18.0-20.0%, TiO2: 30.0-31.0%). This parameter optimization allows the glass to simultaneously achieve high refractive index (enabling thinner light guide plates) and high light transmittance (particularly in blue wavelength range), resolving the contradiction between thickness reduction and transmittance maintenance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite glass material by combining multiple oxide components in specific proportions. The synergistic effect of SiO2, B2O3, La2O3, and TiO2 produces a glass composition that achieves both high refractive index and high transmittance properties, overcoming the limitations of conventional single-component or simpler composite glass formulations

Inventive Principle:
Principle #40Composite materials

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 optical glass achieves high refractive index and light transmittance, enabling the design of thinner light guide plates with improved blue light transmission and reduced devitrification, suitable for continuous industrial production.

Implementation Method 1

TiO 2 is a component that, typically, increases the refractive index of glass

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an optical glass having a high refractive index and high light transmittance has been desired

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP3915952B1Optical glass
Publication Date: 2022.12.28 AGC INC

AI summary

Provided is an optical glass having a high refractive index and high light transmittance. The optical glass contains, in terms of mol% based on oxides, SiO2: 9.0% to 11.0%, B2O3: 22.0% to 24.0%, La2O3: 18.0% to 20.0%, and TiO2: 30.0% to 31.0%.