High-Index Optical Glass Light Guide Plate for AR
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Solution Overview
Problem
Current light guide plates for Augmented Reality devices face challenges in achieving high refractive index, high transmission, and low density, which are essential for effective light guidance and wear comfort, particularly in eyeglasses applications.
Innovation Solution
A light guide plate made from optical glass with a refractive index of at least 1.75, containing Nb2O5 in at least 15 mol% and P2O5 in at least 19 mol%, achieving an internal transmission of 0.80 or more at a wavelength of 440 nm and a sample thickness of 10 mm, while maintaining low weight and minimal warp and bow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical materials are used in light guide plates, then the refractive index is insufficient for effective light guidance, but increasing the refractive index typically increases the density and reduces transmission
Solution Approach 1:
The patent changes the chemical composition parameters of the optical glass by incorporating specific amounts of Nb2O5 (15-40 mol%) and P2O5 (15-30 mol%), which fundamentally alters the optical and physical properties of the material to achieve high refractive index with low density
Solution Approach 2:
The patent creates a composite optical glass system combining multiple oxides (Nb2O5, P2O5, B2O3, SiO2, Al2O3, and metal oxides) to achieve a synergistic effect where the combination provides both high refractive index and low density, overcoming the limitations of individual materials
2Reliability
If the light guide plate transmits light over several cm distance, then the transmission requirement is high, but this increases the weight for wear comfort
Solution Approach 1:
The patent optimizes the chemical composition parameters to achieve exceptional internal transmission (≥0.80 at 440 nm for 10 mm thickness) while maintaining low density, allowing the material to transmit light effectively over several cm distances without excessive weight
Solution Approach 2:
The patent optimizes the local optical properties of the glass material by controlling the distribution and concentration of specific oxide components, creating a material with tailored transmission characteristics for the specific application requirements
3Illumination intensity
If high refractive index materials are used to improve light guidance, then the transmission and density control becomes difficult
Solution Approach 1:
The patent systematically adjusts the composition parameters within specific ranges (Nb2O5: 15-40 mol%, P2O5: 15-30 mol%, B2O3: 5-20 mol%, etc.) to achieve the optimal balance between refractive index and transmission, demonstrating that precise parameter control enables simultaneous optimization of both properties
Solution Approach 2:
The patent incorporates B2O3 and P2O5 which can create a modified glass structure with controlled porosity or free volume, reducing density while maintaining or enhancing optical transmission properties
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 light guide plate with enhanced optical properties, including high internal transmission and low density, ensuring effective light guidance and improved wear comfort in Augmented Reality devices.
Implementation Method 1
light guide plates are planar wafer-like structures that are used for transmitting light. Thus, light is fed into the light guide plate in one position, is transmitted through the light guide plate and leaves the light guide plate at another position
Data Source
AI summary
A light guide plate includes: an optical glass, the optical glass having a refractive index nd of at least 1.75 or of at least 1.80 and including Nb2O5 in an amount of at least 15 mol % and P2O5 in an amount of at least 19 mol %, the light guide plate having an internal transmission of at least 0.80 or of at least 0.90, measured at a wavelength of 440 nm and a sample thickness of 10 mm.