Optical Glass Composition for High Refractive Index and Low Dispersibility
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Solution Overview
Problem
Existing optical glasses face limitations in achieving a balance between high refractive index and low dispersibility, particularly in the near-infrared region, with existing compositions either having insufficient refractive index or high Abbe number, leading to suboptimal performance in security camera lenses and other optical systems.
Innovation Solution
An optical glass composition is optimized by including B2O3 and LaF3 as essential components without Zn, with controlled ratios of La2O3, Gd2O3, Y2O3, LaF3, GdF3, and YF3 to achieve high refractive index and low dispersibility, while ensuring high transmittance in the near-infrared region by excluding components with absorption in this range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If existing optical glass compositions are used to achieve high refractive index, then the refractive index is improved, but the dispersibility worsens (Abbe number is insufficient)
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of multiple oxides and fluorides. Specifically, it adjusts the content ranges of B2O3 (15-35%), La2O3 (0-50%), Gd2O3 (0-50%), Y2O3 (0-20%), LaF3 (10-60%), GdF3 (0-20%), and YF3 (0-20%) to achieve the optimal balance between refractive index (1.65-1.78) and Abbe number (52-65), resolving the contradiction between high refractive index and low dispersibility.
Solution Approach 2:
The patent employs composite materials by combining multiple glass-forming and modifying components in specific proportions. The composition includes a complex mixture of B2O3, SiO2, La2O3, Gd2O3, Y2O3, LaF3, GdF3, YF3, and other metal oxides and fluorides, creating a composite glass system that simultaneously achieves high refractive index and low dispersibility through synergistic effects of the components.
2Illumination intensity
If existing optical glass compositions are used for security camera lenses, then the optical performance is improved, but the near-infrared transmittance worsens
Solution Approach 1:
The patent applies the extraction principle by removing or minimizing components that cause near-infrared absorption. It excludes or limits the use of certain metal oxides known to have absorption bands in the near-infrared region, while maintaining the essential B2O3-LaF3-GdF3-YF3 system that provides high optical performance without compromising near-infrared transmittance.
Solution Approach 2:
The patent uses parameter changes by adjusting the chemical composition parameters to eliminate near-infrared absorption peaks. Specifically, it controls the content of B2O3 (15-35%) and the ratios of rare earth oxides and fluorides to shift or eliminate absorption bands in the near-infrared region, thereby achieving both high optical performance and high near-infrared transmittance (>80% at 800-1100nm).
Data Source
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AI summary
Provided is an optical glass having high refractive index and low dispersibility, and also having high transmittance in the near-infrared region. An optical glass of the present disclosure contains B2O3 and LaF3 as essential components without containing a Zn component and a component having absorption in the near-infrared region, in which the total content of La2O3, Gd2O3, and Y2O3 and the total content of LaF3, GdF3, and YF3 are optimized.