Konica Minolta Opto, Inc.

Hiroaki Sawada

Hideki Kawai

Shinichi Saeki

Yukitoshi Nakatsuji

Kenichi Sasaki

A method for fabricating a glass substrate containing SiOas a main ingredient thereof for an information recording medium which ensures removal of abrasive or foreign mater adhered to the glass substrate without complicating a cleaning step, involves, after a polishing step, keeping the surface of the glass substrate in contact with a liquid having a Si element elution in a range from 100 to 10 000 ppb/mmbefore a scrub-cleaning step.

Method for fabricating a glass substrate for an information recording medium, and magnetic disk using the same

A method for cleaning a glass substrate which ensures removal of abrasive and other foreign matter without making a cleaning step complicated involves cleaning the glass substrate by scrubbing using two or more types of cleaning liquid having different Si element elution abilities. The cleaning liquid having the highest Si element elution is used first, and the cleaning liquid having the lowest Si element elution is used last.

Method for cleaning a glass substrate, method for fabricating a glass substrate, and magnetic disk using same

Provided are a glass substrate for an information recording medium, which has both high strength and high flatness and can be manufactured at low cost, a method for manufacturing such glass substrate and an information recording medium using such glass substrate. The glass substrate for the information recording medium satisfies inequalities of 0.1&#x2266;(W1&#x2212;W3)/W2&#x2266;5, where, W1 is an ion concentration at the center portion in the thickness direction of the glass substrate in a chemically reinforced region at the outer circumference end surface and the inner circumference end surface of the glass substrate and is the maximum value of Kion concentration, W2 is a Naion concentration at a position where the Kion concentration is maximum, and W3 is a Kion concentration in a glass substrate region not chemically reinforced.

Glass substrate for an information recording medium, method for manufacturing a glass substrate for an information recording medium, and an information recording medium

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Sakai, Japan

Hiroaki Sawada