Optical glass with high refraction index and manufacturing method thereof

Abstract

The invention provides optical glass which has the optical characteristics that the refractive index nd is more than 1.80 and less than 1.86 and the Abbe coefficient vd is more than 30 and less than 35. The optical glass contains the following necessary components: SiO2, B2O3, La2O3, Gd2O3, Nb2O5, TiO2, CaO and Li2O. The glass transition temperature (Tg) is below 610 DEG C. The invention also provides a preparation method of the optical glass. The invention provides the optical glass which has small specific gravity and low liquidus temperature obtained during smelting and molding, high transmissivity and excellent chemical stability, and low transition temperature during molding and also provides a high-quality optical element formed by the optical glass.

Description

technical field [0001] The present invention relates to an optical glass, especially an optical glass with low transition temperature, high refractive index and medium dispersion, especially with excellent chemical stability, suitable for stable mass production and precision molding, and meeting the requirements of Optical glass for long-lasting use in precision molding dies. Background technique [0002] Spherical lenses and aspheric lenses are mainly used in the optical system, and most spherical lenses are obtained by direct processing, cutting and grinding of materials, or reprocessing after secondary molding, while aspheric lenses use high-precision The molding mold of the surface is stamped and formed by heating and softening the preform of the lens, and the shape of the high-precision molding surface is pressed on the preformed optical element to obtain an aspheric lens. [0003] However, when performing precision pressing of aspheric lenses, stamping is carried out ...

AI Technical Summary

Problems solved by technology

[0006] SiO 2 / B 2 o 3 The ratio does not satisfy more than 0.27, and the glass composition contains a large amount of Na 2 O component, which is easy to cause instability in production, and at the same time, the stability of glass transition is insufficient, and the glass transmittance and liquidus temperature are not expressed.

Disclosed as CN1669966A is close to the optical glass of above-mentioned range optical characteristic, but from the La of specific composition 2 o 3 / Gd 2 o 3 The ratio does not meet the requirements above 1.5, and

[0007] Nb 2 o 5 / (La 2 o 3 +Gd 2 o 3 +Y 2 o 3 ) is more than 0.4, and contains a relatively large amount of Na 2 O, K 2 O and Bi 2 o 3 components, so it will bring about insufficient chemical stability and instability in production

At the same time the high content of WO 3 The composition is easy to cause erosion and damage to the surface of the mold, thereby shortening the service life of the mold

CN101058475A discloses optical glass with optical properties in the above range, but SiO 2 / ZnO+Li 2 The ratio of O is not more than 1.2, and La 2 o 3 +Gd 2 o 3 +Y 2 o 3 The total amount does not meet more than 45%, and there is also a high content of WO 3 and Na 2 O, K 2 O component, which will cause damage to precision molds and deteriorate chemical stability and process performance, and is not suitable for stable mass production

CN101003417A discloses an optical glass with optical properties within the above range, but it does not belong to the category of low transition temperature and cannot be used for precision molding, and at the same time, the transmittance and chemical stability of the glass are not expressed

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