Optical Glass for Light Guide Plates with High Refractive Index

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Solution Overview

Problem

Current optical glasses used in light guide plates for image display devices have limitations in achieving a wide viewing angle and high transmittance, particularly in the ultraviolet to visible wavelength range, which affects the clarity and efficiency of image display, especially in applications like Augmented Reality.

Innovation Solution

Development of optical glass with a refractive index of 2.00000 or more, specific spectral transmittance characteristics, and composition including B2O3, SiO2, TiO2, Nb2O5, Y2O3, La2O3, and Gd2O3, which enhances the viewing angle and transmittance while blocking ultraviolet light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If optical glass with high refractive index is used to widen viewing angle, then the viewing angle increases, but the spectral transmittance in ultraviolet to visible range decreases

Engineering Contradiction:

Improveviewing angleVSAvoidspectral transmittance

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the optical glass by incorporating specific metal oxides (Nb2O5, TiO2, B2O3, Y2O3, La2O3, Gd2O3) in controlled amounts to achieve a refractive index of 2.00000 or more while maintaining spectral transmittance characteristics with λ5 between 370-410 nm and λ70-λ5 ≤ 70 nm

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite glass material combining multiple oxide components (SiO2, B2O3, TiO2, Nb2O5, Y2O3, La2O3, Gd2O3) to achieve the desired optical properties that cannot be obtained with single-component glasses, specifically achieving high refractive index while maintaining appropriate transmittance

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If optical glass with high refractive index is used to widen viewing angle, then the viewing angle increases, but the image clarity decreases

Engineering Contradiction:

Improveviewing angleVSAvoidimage clarity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the spectral transmittance parameters by controlling λ5 to be between 370-410 nm and the difference λ70-λ5 to be 70 nm or less, which ensures that the high refractive index glass maintains good image clarity while providing wide viewing angle 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 optical glass solution provides a wider viewing angle and improved image clarity by optimizing refractive index and spectral transmittance, making it suitable for light guide plates in image display devices, particularly for AR applications.

Implementation Method 1

a wavelength λ5, which provides a spectral transmittance of 5% for a thickness of 10 mm, of more than 370 nm and less than 410 nm

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

a refractive index nd of 2.00000 or more

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS20240327268A1Optical glass, light guide plate, image display device and optical element

Publication Date: 2024.10.03 HOYA CORPORATION

AI summary

The optical glass has a wavelength λ5, which provides a spectral transmittance of 5% for a thickness of 10 mm, of more than 370 nm and less than 410 nm, a difference (λ70−λ5) between a wavelength λ70, which provides a spectral transmittance of 70% for a thickness of 10 mm, and λ5, of 70 nm or less, and a refractive index nd of 2.00000 or more.