METHOD OF POLISHING GLASS MATERIAL FOR INFORMATION RECORDING GLASS SUBSTRATE, INFORMATION RECORDING GLASS SUBSTRATE, INFORMATION RECORDING DISK, AND HARD DISK DRIVE

摘要

PROBLEM TO BE SOLVED: To improve annular strength of glass material for an information recording glass substrate without performing process of chemical reinforcement and to improve alkali resistance.;SOLUTION: A main surface of the toroidal glass material for the information recording glass substrate is mechanically polished so that surface roughness Ra (JIS B 0601) falls within a range from 0.1 to 0.9 μm, and then, an inner peripheral surface and outer peripheral surface of the glass material are finely polished, the glass material is chemically polished, and further, the main surface is subjected to final polishing. By implementing chemical polishing, the annular strength is improved and the glass material becomes resistant to breaking. Further, compared to glass material subjected to the process of chemical reinforcement, the glass material excels in alkali resistance.;COPYRIGHT: (C)2008,JPO&INPIT