Nippon Sheet Glass Company, Limited

Nippon Sheet Glass Do., Ltd.

Shinya Katayama

Yoshihiro Matsuno

Toshiyuki Sato

Atsunori Matsuda

Toshio Tsuno

Tomoyasu Shimizu

Akihiro Koyama

Tsutomu Minami

Yasunao Kuroda

Toshihiro Kogure

Shinya Kawakita

Noboru Akazawa

Noboru Tohge

Jyunji Kurachi

Manabu Takami

This invention relates to a magnetic recording medium having a structure in which an undercoating film, a magnetic thin film, a protective film, and an organic film are stacked on a substrate in the order named. Since the protective film contains carbon and silicon and a portion of silicon in at least an interface in contact with the organic film consists of a silicon oxide, the surface of the magnetic recording medium is not degraded even by frequent contact with a magnetic head upon driving or stopping of the magnetic recording medium. This invention also relates to a method of manufacturing the same.

Magnetic recording medium and a method of manufacturing the same

A glass substrate for a magnetic disk of the present invention is one in which a laser beam is irradiated on a main surface thereby forming a large number of protrusions thereon to form texture thereon, each of said protrusions being formed by a protruded portion having a convex shape, said glass having a composition in which 0.2 to 3 wt % of an oxide of a transition metal is contained and an absorption coefficient with respect to a wavelength of a light at 266 nm being within a range of 0.03 to 2 .mu.m.sup.-1, and by setting the absorption coefficient of the glass with respect to a wavelength of a light at 266 nm within a range of 0.03 to 2 .mu.m.sup.-1 and irradiating a laser beam having a wavelength in a range of ultraviolet rays selectively on the main surface of a glass substrate at predetermined intervals, texture comprising a large number of protrusions formed by protruded portions each having a small diameter and a convex shape is formed.

Glass substrate for magnetic disks

The optical parts according to the invention have a feature of having smoothly coated surfaces for incident and emergent lights covered thereover with a light transmitting solid coating layer, and can be manufactured by a simplified process at least without needing polishing, together with the advantages of being weatherproof in atmosphere of high temperature and high humidity and antiozonant.

Optical part

A substrate used for magnetic disk comprising s non-magnetic support in which a material for forming pits is formed on the surface, wherein the material for forming the surface pits comprises a low melting metal and has an island structure discontinuous in the direction within the plane at the surface of the non-magnetic support, thereby enabling to produce a magnetic disk of excellent magnetic property at high productivity, as well as a magnetic recording medium using such a substrate.

Substrate used for magnetic disk and magnetic recording medium using the

Disclosed herein is a process for producing a minute-patterned substrate required for optical disk substrates for information recording or the like, which process comprises forming a coating film of a solution containing a metal-organic compound and a thickener on a substrate, pressing a mold against the coating film on the substrate under a reduced pressure and heating the coating film to set up the coating film, then removing the mold, and heating the set coating film on the substrate. By the process it is possible to provide the substrate surface with a minute rough pattern, without generation of surface defects arising from the pressing of the mold against the coating film, and to set up the coating film in a short time and with good dimensional accuracy. It is therefore possible to produce a rough surface pattern with high productivity.

Process for producing a minute-patterned substrate

In a magnetic recording medium having a layer of a perfluoroalkylpolyether-based liquid lubricant as an uppermost layer, the liquid lubricant has an atomic group including an aromatic ring at a terminal end of a perfluoropolyether main chain, and is coated on an inorganic oxide. Therefore, adhesion force of the lubricant is greatly improved, and interaction within the lubricant can be decreased, thus realizing a magnetic recording medium having excellent lubricity and wear resistance.

Magnetic recording medium with an intermediate protective layer of

A substrate provided thereon, with a film having a large number of fine grooves of a desired pattern is herein disclosed, which comprises a body of substrate and a film of at least one polymerized-condensed or crosslinked organometal compound formed on the substrate and having a large number of fine grooves on the surface and which can be produced by applying a solution containing at least one organometal compound and optionally a thickening agent to the surface of a body of substrate to form a film thereon; then impressing the film with a mold having a large number of fine ridges thereon to form grooves corresponding to the ridges, on the film; or applying the solution to the mold to form such a film and transferring the film to the body of substrate; and then calcining the resulting film having fine grooves to solidify the same. According to the method, an excellent substrate having good durability and optical properties can be produced simply and in a good yield.

Growing community of inventors

Tsukuba, Japan

Shinya Katayama