Hoya Corporation

Hoya Glass Disk Vietnam Ii Ltd.

Hoya Glass Disk (thailand) Ltd.

Oki Electric Industry Co., Ltd.

Resonac Corporation

Hitachi Chemical Company, Ltd.

Hoya Lamphun Ltd.

Toshio Takizawa

Kinobu Osakabe

Masanobu Itaya

Kenichi Nishimori

Kraisorn Phandon

Shuhei Azuma

Masayuki Hanano

Hisato Takahashi

Yoshinori Marumo

Munehiro Oota

Masahiro Katagiri

Takumi Koshimizu

Tomohiro Iwano

Takahiro Yoshikawa

Hisataka Minami

Toshiaki Akutsu

Takashi Shinoda

Akira Ugawa

Hiroharu Hirata

Takaaki Tanaka

Shigeru Yoshikawa

Kiyokazu Narita

Kraisom Phandon

Takaaki Matsumoto

A disk-shaped glass substrate manufacturing method for manufacturing a glass substrate () includes preparing a disk-shaped glass blank having main surfaces () and an outer circumferential end face (), and irradiating the disk-shaped glass blank with a laser beam (L) along a distance longer than one lap of the outer circumferential end face () of the disk-shaped glass blank.

Magnetic disk-use glass substrate manufacturing method, discoidal glass substrate, glass substrate, and magnetic disk-use glass substrate

A polishing liquid includes abrasive grains containing at least one selected from the group consisting of cerium oxide and silicon oxide; a nitrogen-containing compound; and water. The nitrogen-containing compound contains nicotinamide. A polishing liquid set includes constituent components of a polishing liquid stored while being divided into a first liquid and a second liquid. A polishing method includes a step of polishing a surface to be polished by using a polishing liquid.

Polishing liquid, polishing liquid set, polishing method, and defect suppression method

Chamfering processing for chamfering an edge face of a disk-shaped glass plate includes a step of disposing the glass plate such that a portion of the glass plate is disposed in a heating space for heating the glass plate and the remaining portion is disposed outside the heating space; and a step of softening a portion of the edge face of the glass plate by irradiating a circumferential portion of the edge face with a laser beam outside the heating space while rotating the glass plate in one direction around the center of the glass plate, and heating the softened portion of the edge face that has reached the heating space through the rotation.

Method for manufacturing glass plate, method for manufacturing magnetic-disk glass substrate, and method for manufacturing magnetic disk

A magnetic-disk substrate according to an embodiment includes two main surfaces and an outer circumferential edge surface. In the magnetic-disk substrate, the outer circumferential edge surface includes two chamfered surfaces that are respectively connected to the main surfaces, and a side wall surface that is curved and extends to protrude outward between the two chamfered surfaces. The side wall surface has a radius of curvature of 1100 μm or more on a cross-section of the magnetic-disk substrate extending along a plate thickness direction of the magnetic-disk substrate.

Magnetic disk substrate, magnetic disk, annular-shaped substrate, and method for manufacturing magnetic disk substrate

Letting a particle diameter be Dx (μm) when a cumulative particle volume cumulated from the small particle diameter side reaches x (%) of the total particle volume in a particle size distribution obtained regarding cerium oxide included in a polishing liquid using a laser diffraction/scattering method, D5 is 1 μm or less, D100 is 3 μm or more, D50 is 0.8 to 2.4 μm, and Dpeak−D5 is less than D95−Dpeak.

Polishing liquid and method for manufacturing glass substrate

A magnetic-disk substrate has an average value of squares of inclinations that is 0.0025 or less, and a frequency at which squares of inclinations are 0.004 or more is 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm. The main surface is configured to receive at least a magnetic recording layer thereon. The magnetic-disk substrate includes an outer circumferential end portion and an inner circumferential end portion, and the outer circumferential end portion and the inner circumferential end portion have chamfered portions.

Magnetic-disk substrate and magnetic disk

A polishing liquid containing: abrasive grains; a first nitrogen-containing compound; a second nitrogen-containing compound; and water, in which the first nitrogen-containing compound contains at least one selected from the group consisting of (I) a compound having an aromatic ring containing one nitrogen atom in the ring and a hydroxyl group, (II) a compound having an aromatic ring containing one nitrogen atom in the ring and a functional group containing a nitrogen atom, (III) a compound having a 6-membered ring containing two nitrogen atoms in the ring, (IV) a compound having a benzene ring and a ring containing a nitrogen atom in the ring, and (V) a compound having a benzene ring to which two or more functional groups containing a nitrogen atom are bonded, and an HLB value of the second nitrogen-containing compound is 7 or more.

Polishing solution, polishing solution set, polishing method, and defect suppressing method

Letting a particle diameter be Dx (&#x3bc;m) when a cumulative particle volume cumulated from the small particle diameter side reaches x (%) of the total particle volume in a particle size distribution obtained regarding cerium oxide included in a polishing liquid using a laser diffraction/scattering method, D5 is 1 &#x3bc;m or less, and a difference between D95 and D5 is 3 &#x3bc;m or more.

Polishing liquid, method for manufacturing glass substrate, and method for manufacturing magnetic disk

Provided is a CMP polishing liquid used for removing a part of an insulating portion of a base substrate, which includes a substrate, a stopper provided on one surface of the substrate, and the insulating portion provided on a surface of the stopper opposite to the substrate, by CMP to expose the stopper, the polishing liquid containing: abrasive grains containing cerium; a nonionic water-soluble compound A; a polymer compound B having at least one selected from the group consisting of carboxylic acid groups and carboxylate groups; a basic pH adjusting agent which is optionally contained; and water, in which a content of the basic pH adjusting agent is less than 1.3&#xd7;10mol/kg based on the total mass of the polishing liquid.

Polishing liquid, polishing liquid set and polishing method

A hard disk drive includes a magnetic-disk substrate in which an average value of squares of inclinations is 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more is 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.

Hard disk drive with magnetic-disk substrate and hard disk drive with magnetic disk

A magnetic disk substrate having a flat main surface, an end face, and a chamfered face formed between the main surface and the end face. The substrate has an offset portion, present on the main surface within a range of 92.0 to 97.0% in a radial direction from a center of the substrate. A distance from the center of the substrate to the end face of the substrate in a radial direction is 100%, the offset portion being raised or lowered with respect to a virtual straight line connecting two points on the main surface, set at positions of 92.0% and 97.0%. A maximum distance from the virtual straight line to the offset portion in a direction perpendicular to the virtual straight line is a 'maximum offset value.'

Magnetic disk substrate with specified changes in height or depth between adjacent raised or lowered portions and an offset portion on a main surface within a range of 92.0 to 97.0% in a radial direction from a center, a magnetic disk with substrate and magnetic disk device

A magnetic-disk glass substrate of the present invention has an average value of squares of inclinations of 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more of 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.

A polishing liquid for CMP, comprising: an abrasive grain including a cerium-based compound; a 4-pyrone-based compound; a polymer compound having an aromatic ring and a polyoxyalkylene chain; a cationic polymer; and water.

Growing community of inventors

Tokyo, Japan

Toshio Takizawa