US 6,599,606 B1 · Process for preparation of crystallized glass for information recording disk

Abstract

Disclosed is a process for preparation of crystallized glass obtained by making a glass containing TiO2 subjected to a phase separation step and a crystallization step, where the phase separation step has heat treatment of the glass at a temperature in a range from a temperature of the glass transition temperature Tg (Tg−30° C.) to a temperature 60° C. higher than the glass transition temperature Tg (Tg+60° C.). There are also disclosed a crystallized glass for information recording disk composed of the crystallized glass obtained by the preparation process, where a mean particle size of the crystal particles is in a range of equal to or less than 100 nm, or where a transparency at a wavelength of 600 nm is 40% or higher; and an information recording disk, composed of the glass, having a polished surface with a surface roughness Ra (JIS B0601) in a range from 0.1 to 0.5 nm.

Claims31

Dependent claims

A process for preparation of a crystallized glass plate in a disk shape comprising a step of phase separation of a starting glass containing TiO2 and a step of crystallization of the resulting phase-separated glass,

wherein the phase separation step comprises a heat treatment of the starting glass at a temperature in a range from a temperature 30° C. lower than a glass transition temperature (Tg) of the glass to a temperature 60° C. higher than the glass transition temperature (Tg);
wherein the crystallized glass comprises enstatite and/or its solid solution as a main crystal.

Dependencies are inferred from the claim text.

Process for preparation of crystallized glass for information recording disk

Life of this patent

Process for preparation of crystallized glass for information recording disk

Life of this patent

Abstract

Claims31