Nippon Sheet Glass Company, Limited

Hoya Corporation

Nippon Sheet Glass Do., Ltd.

Yoshihiro Matsuno

Akihiro Koyama

Yasuhiro Saito

Kazuishi Mitani

Nobuyuki Yamamoto

Junji Kurachi

Shinya Katayama

Koichi Ataka

Hiroshi Ikeda

Takeo Watanabe

Atsunori Matsuda

Tsutomu Minami

Yasunao Kuroda

Kazuaki Kanai

Tatsuro Umeyama

Toshio Tsuno

Noboru Akazawa

Noboru Tohge

Manabu Takami

Jyunji Kurachi

A method of manufacturing a glass substrate for a magnetic disk. The method includes the step of scrub-etching the glass substrate using a pad in the presence of an acid treatment solution. As the acid treatment solution, hydrofluoric acid is used in a range of 0.01 to 1 wt %. The scrub-etching step is performed at temperatures ranging from 5 to 60&#xb0; C. for 1 second to 300 seconds. The method produces a substrate that is substantially free of asperity.

Glass substrate for magnetic disk and method for manufacturing

A glass substrate for use as an information recording medium has an average surface roughness (Ra) in the range of 0.3 nm&lE;Ra<3.0 nm and includes surface irregularities shaped and distributed isotropically and arranged substantially in succession. The surface irregularities include 5 to 50,000 convexities having a height of at least 3 nm and no convexities having a height of at least 15 nm within an area of 50 &mgr;m&times;50 &mgr;m. A porous region produced by an acid treatment process in the glass substrate would be completely removed if excessively etched by an alkaline solution. However, the etching process using the alkaline solution can be stopped at a stage where the pores in the porous region are enlarged by controlling conditions for the acid and alkali treatment processes.

Glass substrate for use as information recording medium and method of manufacturing such glass substrate

A method of manufacturing a glass substrate for a magnetic disk. The method includes the step of scrub-etching the glass substrate using a pad in the presence of an acid treatment solution. As the acid treatment solution, hydrofluoric acid is used in a range of 0.01 to 1 wt %. The scrub-etching step is performed at temperatures ranging from 5 to 60&deg; C. for 1 second to 300 seconds. The method produces a substrate that is substantially free of asperity.

Method of manufacturing glass substrate for use as information recording medium

A glass substrate for an information recording medium has an acid resistance represented by an etching rate of at most 45 nm/min. upon contact with a hydrofluoric acid having a temperature of 50&deg; C. and a concentration of 0.1 weight %. The glass substrate has a recording surface having an average surface roughness Ra smaller than 0.3 nm.

Glass substrate for information recording medium, manufacturing method thereof, and information recording medium

Substrate for information recording media

Hydrofluoric acid etched substrate for information recording medium

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

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

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.

Substrate with fine grooves and method for manufacturing the same

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Osaka, Japan

Yoshihiro Matsuno