Glass material for press molding, method of manufacturing glass material for press molding and method of manufacturing optical element

Abstract

The invention provides a glass material for press molding, a method for manufacturing a glass material for press molding, and a method of manufacturing an optical element, which are capable of obtaining a desired optical performance without impairing the shape accuracy of the optical element obtained by press molding and providing such at low cost. According to the invention, a glass blank (10) for press molding is provided, wherein the glass material (10) for press molding comprises at least one convex surface (10a) having a surface roughness Ra being a first surface roughness Ra1 and a side end face (11) configured around the convex surface and having a surface roughness Ra being a second surface roughness Ra2, the second surface roughness Ra2 being less than 0.10 m, and the second surface roughness Ra2 being larger than the first surface roughness Ra1.

Description

technical field [0001] The present invention relates to a glass blank for press molding and a method for manufacturing the glass blank for press molding, in particular to a glass blank for press molding having at least one convex surface, a method for manufacturing the glass blank for press molding, and a method for manufacturing an optical element. Background technique [0002] As one of the methods of manufacturing an optical element (glass lens) having at least one convex surface, there is a molding method of pressing a glass blank for press molding having at least one convex surface with a molding die. [0003] The side end surface of the glass material for press molding formed by cold working such as a centering process generally has a frosted rough surface with acute-angle irregularities. Therefore, in the above-mentioned molding method, the sharp-angled concavo-convex front end may detach from the side end surface of the glass blank for press molding as fine particles...

AI Technical Summary

Problems solved by technology

Therefore, in the above-mentioned molding method, the sharp-angled concave-convex front end may detach from the side end surface of the glass blank for press molding in the form of fine particles and fall on the molding die.

In addition, there is a problem that such fine particles enter between the press-molding glass blank and the molding die during press-molding, and dot-shaped defective parts occur on the surface of the optical element (glass lens) obtained by press-molding.

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