Optical glass, glass preform, optical element and optical instrument

Abstract

The invention provides optical glass which comprises the following components in percentage by weight: 2-20% of SiO2; 8-30% of B2O3; 8-25% of La2O3; 15-43% of Nb2O5 and 1 to 15% of BaO, wherein the ratio of Nb2O5 / La2O3 is 0.8 to 3.0. Through reasonable component design, the obtained optical glass has the expected refractive index and Abbe number, meanwhile, the density of the glass is low, and a larger degree of freedom is brought to light weight of an optical system; the optical glass has excellent chemical stability and crystallization resistance, the transmittance cannot be obviously reduced after long-term use, and the optical glass is very suitable for being applied to imaging application needing to bear a severe working environment.

Description

technical field [0001] The invention relates to an optical glass, in particular to a lanthanum-containing optical glass with a refractive index of 1.82-1.90 and an Abbe number of 27-35. Background technique [0002] In the prior art, glass with a refractive index of 1.82-1.90 and an Abbe number of 27-35 belongs to high refractive index glass, and is widely used in various lens designs. In recent years, optical components such as lenses have been required to be lightweight. Especially in aerial photography using small remote-operated machines such as drones, the optical system is required not only to be lightweight, but also to be chemically stable to adapt to harsh environments. [0003] However, in the glass formulation system of the same system, the density and chemical stability of the glass are closely related to the glass structure. The looser the glass structure, the lower the density, which also means that the chemical stability of the glass is reduced. How to reduc...

AI Technical Summary

Problems solved by technology

[0007] If the heavy lanthanum flint glass with the above-mentioned refractive index and Abbe number needs to be lower than 4.0g / cm 3 The density needs to be different from the conventional ones in component design, which usually brings problems such as poor anti-devitrification performance and difficult elimination of streak bubbles to the glass.

If the anti-devitrification performance of the glass is poor, firstly it will increase the production difficulty of the glass blank, resulting in a decrease in the yield rate, and in severe cases, it may even fail to produce normally; secondly, crystal precipitation is prone to occur during the secondary molding process, resulting in a decline in the yield rate. Can't even do secondary molding

For glass materials used in the automotive field, if the yield rate of the glass is low, and the cold processing method cannot be used for secondary molding, the cost will increase significantly

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