Patent application number | Description | Published |
20090162703 | Glass Substrate for Information Recording Medium, and Method of Manufacturing Glass Substrate for Magnetic Recording Medium and Information Recording Medium - Not only chemical durability of a glass substrate for an information recording medium is improved, but also no deformation of the substrate and no alteration of substrate characteristics are to be made. A chemical treatment layer formed on the glass substrate surface is made thicker toward a large surface roughness portion of the glass substrate, prior to being subjected to a chemical treatment, from a small surface roughness portion of the glass substrate. Layer thickness D of the resulting chemical treatment layer preferably satisfies the following inequality (1) in view of acquisition of chemical durability. | 06-25-2009 |
20090252993 | GLASS SUBSTRATE FOR AN INFORMATION RECORDING MEDIUM, METHOD FOR MANUFACTURING A GLASS SUBSTRATE FOR AN INFORMATION RECORDING MEDIUM, AND AN INFORMATION RECORDING MEDIUM - 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≦(W1−W3)/W2≦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 K | 10-08-2009 |
20100007990 | MAGNETIC RECORDING MEDIUM SUBSTRATE, MAGNETIC RECORDING MEDIUM AND METHOD FOR MANUFACTURING MAGNETIC RECORDING MEDIUM SUBSTRATE - Provided are a magnetic recording medium substrate whereupon a magnetic layer can be regularly formed in a recording area, a magnetic recording medium and a method for manufacturing the magnetic recording medium substrate. A plurality of recording areas wherein the magnetic layer is to be formed are formed on the surface of the disk-shaped magnetic recording medium substrate. The size of the recording area is an integral multiple of a lattice constant of a unit lattice of a single crystal structure constituting the magnetic layer. For instance, the width of a protruding section ( | 01-14-2010 |
20100071416 | MOLD FOR GLASS SUBSTRATE MOLDING, METHOD, FOR PRODUCING GLASS SUBSTRATE, METHOD FOR PRODUCING GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM, AND METHOD FOR PRODUCING INFORMATION RECORDING MEDIUM - Disclosed is a mold for glass substrate molding, which enables to produce a glass substrate having high flatness by a method for producing a glass substrate through press molding of molten glass. Also disclosed is a method for producing a glass substrate by using such a mold. Specifically disclosed is a mold comprising a lower mold having a first molding surface for pressing a molten glass supplied thereto, and an upper mold having a second molding surface for pressing the molten glass against the first molding surface. In the first molding surface, the surface roughness Ra of the peripheral portion which is in contact with the molten glass after pressing is higher than the surface roughness Ra of the central portion which is in contact with the molten glass before pressing. | 03-25-2010 |
20100075180 | MAGNETIC RECORDING MEDIUM SUBSTRATE AND MANUFACTURING METHOD THEREOF, AND MAGNETIC RECORDING MEDIUM AND MANUFACTURING METHOD THEREOF - Provided is a magnetic recording medium substrate suitable for preparation of a DT medium and a patterned medium, and the magnetic recording medium substrate is possible to be of easy preparation of the DT medium and the patterned medium with no complicated processes. Disclosed is a magnetic recording medium substrate comprising a circular plate-shaped substrate made of a nonmagnetic base material, wherein a predetermined region of a surface of the substrate to form a magnetic film on the surface is more roughened than another region of the surface. When forming a magnetic film on this substrate, the magnetic film is formed in the region of the substrate surface, which is more roughened than the other region, to easily prepare the DT medium and the patterned medium. | 03-25-2010 |
20100221582 | MAGNETIC RECORDING MEDIUM SUBSTRATE AND MAGNETIC RECORDING MEDIUM - Provided is a magnetic recording medium substrate appropriate for a discrete medium and capable of fabricating a magnetic recording medium to/from which data can be written or read stably. Coaxial grooves ( | 09-02-2010 |
20110039126 | DIE FOR FORMING GLASS SUBSTRATE, METHOD OF MANUFACTURING GLASS SUBSTRATE, METHOD OF MANUFACTURING GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM, METHOD OF MANUFACTURING INFORMATION RECORDING MEDIUM, GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM, AND INFORMATION RECORDING MEDIUM - There are provided a die for forming a glass substrate which does not generate cracks when the glass substrate is released from the die, in a method of manufacturing a glass substrate by forming molten glass with a pressing operation, a method of manufacturing a glass substrate using the die, a method of manufacturing a glass substrate for an information recording medium using a glass substrate manufactured by the method, a method of manufacturing an information recording medium, a glass substrate for an information recording medium, and an information recording medium. In the die for forming a glass substrate used for pressing molten glass to manufacture a glass substrate for an information recording medium, a lower die includes a die surface on which a plurality of grooves or depressions are almost uniformly formed. | 02-17-2011 |
20110111160 | Glass Substrate for Information Recording Medium and Information Recording Medium - A glass substrate for information recording medium, said glass substrate being composed of an alminosilicate glass containing 60-75% by mass of SiO | 05-12-2011 |
20110111161 | GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM AND INFORMATION RECORDING MEDIUM - A glass substrate for information recording medium, said glass substrate being composed of an alminosilicate glass containing 60-75% by mass of SiO | 05-12-2011 |
20110111260 | GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM AND INFORMATION RECORDING MEDIUM - A glass substrate for information recording medium, said glass substrate being composed of an aluminosilicate glass containing 60-75% by mass of SiO | 05-12-2011 |
20110111263 | GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM AND INFORMATION RECORDING MEDIUM - A glass substrate for information recording medium, said glass substrate being composed of an alminosilicate glass containing 60-75% by mass of SiO | 05-12-2011 |
20110195638 | METHOD FOR PRODUCING GLASS SUBSTRATE AND METHOD FOR PRODUCING MAGNETIC RECORDING MEDIUM - Disclosed is a method for producing a glass substrate, which involves a first polishing step and a second polishing step both for polishing the surface of the glass substrate with a polishing solution containing a polishing agent. The method is characterized by additionally involving a heating step for heating the glass substrate, wherein the heating step is carried out after the first polishing step and before the second polishing step. | 08-11-2011 |