Optical glass, glass preform, optical element and optical instrument

Abstract

The invention provides optical glass. The optical glass comprises the following components in percentage by weight: 2-25% of SiO2, 12-40% of B2O3, 2-20% of Al2O3, 30-65% of Ln2O3 and 0-15% of RO. The refractive index nd of the optical glass is more than 1.66, the ratio of (SiO2+Al2O3+Ln2O3) to (RO+B2O3+nd x 8) is 0.6-3.0, the Ln2O3 is the total content of La2O3, Y2O3 and Gd2O3, and the RO is the total content of MgO, CaO, SrO and BaO. The refractive index of the obtained optical glass is more than 1.66, the Abbe number is more than 50, the machinability and chemical durability are obviously superior to that of the prior art, the transmittance is not obviously reduced after long-term use, and the optical glass is very suitable for outdoor monitoring cameras and vehicle-mounted lenses, and is particularly suitable for being applied to imaging applications needing to bear severe working environments.

Description

technical field [0001] The invention relates to an optical glass, in particular to an optical glass, a glass preform prepared therefrom, an optical element and an optical instrument. Background technique [0002] In recent years, with the development of digital photography equipment, camera equipment, projection equipment, and vehicle-mounted equipment, the requirements for optical components are getting higher and higher, which requires the development and production of higher-performance optical glass. Among the optical glasses for making optical components, especially for medium-refractive-index low-dispersion optical glasses that can correct chromatic aberration, miniaturize the optical system, have a refractive index greater than 1.66, and have an Abbe number greater than 50, the market demand is increasing day by day. [0003] From the perspective of the existing technology, the lanthanum crown optical glass with medium refractive index and low dispersion mainly adopts...

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Problems solved by technology

[0003] From the perspective of the existing technology, the lanthanum crown optical glass with medium refractive index and low dispersion mainly adopts B 2 o 3 -La 2 o 3 system, however, by these B 2 o 3 -La 2 o 3 Glasses composed of systems are often affected by water or acid in terms of the characteristics of glass components commonly used, and the durability is not sufficient. Therefore, when the glass is polished, the glass may deteriorate, and the yield rate of the manufacturing process is not good.

In addition, due to the increasing demand for surveillance cameras and vehicle cameras in recent years, which are often used outdoors, the existing glass camera elements are mostly exposed to wind, rain or sand. In the case of long-term use, the durability of the glass is difficult to meet the requirements

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