Optical glass

Abstract

The invention provides an optical glass with a refractive index of 1.81-1.88 and an Abbe number of 31-38, which is suitable for secondary molding and aspherical precision molding. Optical glass, the mole percentage composition of its oxides includes: SiO26‑23%, B2O320‑35%, TiO23‑9%, ZnO 17‑42%, La2O33‑18%, Y2O31‑5%, ZrO21‑7%, Nb2O54‑ 10%, WO30.4-4%, BaO 3-15%. In the present invention, the glass ratio is reasonably composed, the glass transmittance is high, the value of τ400nm is higher than 88% and the Tg is lower than 620°C, which is suitable for precision molding of aspheric surfaces; Glass with a thickness greater than 20mm is not easy to produce crystallization and streaks, and the yield rate is high; at the same time, the components do not contain precious oxides such as Ta2O5 and Gd2O3.

Description

technical field [0001] The present invention relates to a high refractive index optical glass, in particular to an optical glass with a refractive index of 1.81-1.88 and an Abbe number of 31-38, which has high transmittance, low crystallization temperature and high molding viscosity, and is suitable for in the secondary pressing. Background technique [0002] For optical glass, the refractive index, Abbe number, and transmittance are its core characteristics. The refractive index and Abbe number determine the basic functions of the glass. The optical glass with a refractive index of 1.81-1.88 and an Abbe number of 31-38 belongs to high-refractive index medium-high dispersion optical glass, which can shorten the imaging length of the lens and combine with low refraction. When used for coupling with low dispersion glass, it can effectively eliminate the chromatic aberration of the lens. [0003] Transmittance is also the core indicator of glass, which represents the ability ...

AI Technical Summary

Problems solved by technology

This creates another problem: the higher the leakage temperature, although it is beneficial to slow crystallization, the viscosity of the glass decreases with the increase of temperature.

However, containing Li 2 The low softening point optical glass of O is usually smelted in a platinum crucible. During the smelting process, the Li in the glass component 2 O is easy to corrode the platinum crucible, resulting in more shedding platinum and platinum crystallization in the finished glass, resulting in a decrease in the yield rate of the glass

On the other hand, when this type of glass is used in the precision molding process, it is prone to the risk of blurring the surface of the glass component, because the mold is generally coated with a release agent containing carbon elements, and the Li in the glass component 2 O is easy to react with the carbon element in the release agent, forming a rough opaque film on the surface of the glass original

[0011] The glass described in Chinese patent 98802074.2, the refractive index and Abbe number overlap with the range of the glass of the present invention to a certain extent, but the ZnO content in its components is very low, resulting in a high Tg temperature, which is not suitable for precision molding of aspheric surfaces

[0012] The glass described in Chinese patent 201210244584.8 has a certain overlap in refractive index and Abbe number with the glass of the present invention, but its Tg temperature is as high as 650°C, which is not suitable for aspheric surface molding. At the same time, its coloring degree is relatively high, reaching 410nm at λ70, This is detrimental to the transmission of the blue light band of the lens

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