Hoya Corporation

Masao Takano

Shinji Eda

Tsuyoshi Watanabe

Koji Takahashi

Takemi Miyamoto

Kashio Nakayama

A hard disk drive includes a magnetic disk, and an annular spacer. The annular space includes two main surfaces, an inner circumferential surface, an outer circumferential surface, and a chamfered surface present between the outer circumferential surface and each of the two main surfaces. The annular spacer is disposed such that one of the two main surfaces is in contact with the magnetic disk. At least one main surface of the two main surfaces includes an inclined region, and the inclined region is inclined in an outer circumferential region of the at least one main surface toward a boundary between the at least one main surface and the chamfered surface such that a surface height of the spacer gradually decreases toward the boundary. The magnetic disk has a thickness of 0.55 mm or less. A material of a substrate for the magnetic disk includes aluminum alloy.

Hard disk drive including annular spacer with inclined region on main surface

A method for manufacturing a substrate includes processing a side face of a laminate that includes substrates and a sheet-shaped spacer disposed between adjacent substrates. The processing of the side face includes bringing the laminate into a pressed state, first side face processing for processing a side face of the laminate in the pressed state, releasing the laminate from the pressed state after the first side face processing, intermediate processing for performing one of dividing the laminate released from the pressed state into two or more laminates, combining the laminate released from the pressed state with another laminate in a stacking direction, and leaving the laminate released from the pressed state as it is, bringing the laminate that has undergone the intermediate processing into a pressed state after the intermediate processing, and processing a side face of the laminate in the pressed state after the intermediate processing.

Method for manufacturing substrate and method for manufacturing substrate for magnetic disk

Provided is an annular spacer to be disposed such that a main surface of the spacer is in contact with a magnetic disk in a hard disk drive device, the spacer including two main surfaces; an inner circumferential surface; and an outer circumferential surface, in which a chamfered surface is present between the outer circumferential surface and each of the two main surfaces, and at least a portion of an outer circumferential region of at least one of the two main surfaces includes an inclined region that is inclined toward the other main surface side in a radial direction from a center of the spacer to the outer circumferential surface side.

Hard disk drive spacer having chamfered surface and main surface with inclined region

A sheet-like spacer to be used when a laminate of a plurality of substrates is formed for the purpose of processing end faces of the substrates is provided between the adjacent substrates in the laminate to keep the adjacent substrates apart from each other. An area of the spacer is smaller than that of the substrates. A contact angle of a surface of the spacer with respect to pure water is 50&#xb0; or less.

Spacer and laminate

A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank; and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.

Method for manufacturing ring-shaped glass spacer

The area of a spacer that is to be provided between the adjacent substrates in a laminate including a plurality of substrates to keep the adjacent substrates apart from each other is smaller than those of the stacked substrates. When pressure is released to bring the laminate obtained by providing the spacers between the substrates from a pressed state in which 0.60 MPa of pressure is applied to the laminate in the stacking direction into a non-pressed state, an amount of change &#x394;W in thickness per spacer that is calculated from a change in the thickness of the laminate due to the release of pressure is 30 &#x3bc;m or less.

Spacer, laminate of substrates, method for manufacturing substrate, and method for manufacturing substrate for magnetic disk

In order to suppress the occurrence of adhesion between magnetic disks and spacers when the magnetic disks and the spacers are removed from a hard disk drive apparatus in which the magnetic disks and the spacers are installed, a surface roughness Ra of a main surface of a ring-shaped glass spacer to be arranged in contact with a magnetic disk is set to be not larger than 1.0 &#x3bc;m, and an average inclination R&#x394;a of the main surface is set to be at least 0.02.

Glass spacer and hard disk drive apparatus

A ring-shaped spacer is to be arranged in contact with a magnetic disk in a hard disk drive apparatus. A maximum height surface roughness Rz of an outer circumferential edge surface of the spacer is at least 1.5 &#x3bc;m, and the spacer is made of amorphous glass.

Spacer and hard disk drive apparatus

When removing magnetic disks and spacers from a hard disk drive apparatus, as necessary, during the assembly of the hard disk drive apparatus, in order to suppress the occurrence of removal failures when removing the spacers using a gripping jig, a surface roughness Rz of an outer circumferential edge surface of a spacer is set to be at least 1.5 &#x3bc;m.

On a principal surface of a glass disk substrate, a texture comprising a combination of an isotropic texture for stabilizing a flight of a magnetic head flying and traveling over a magnetic disk and an anisotropic texture for imparting a magnetic anisotropy to a magnetic layer of the magnetic disk is formed.

Glass substrate for a magnetic disk, magnetic disk, and methods of producing the glass substrate and the magnetic disk

In a magnetic recording medium, surface roughness of a glass substrate and the variation of the surface roughness are suppressed to the predetermined range. Namely, the surface roughness (Rmax, Ra, Rq) and the relation (Rmax/Ra) between Rmax and Ra are restricted to the predetermined range. In this event, Ra is representative of a center-line mean roughness, Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point and Rq is representative of a root mean square roughness. Thereby, crystal grains of an underlying layer and a magnetic layer formed thereon are equalized. Specifically, the surface roughness is specified by Rmax&#x2266;15 nm, Ra&#x2266;1 nm and Rq&#x2266;1.5 nm. Further, the ratio between the surface roughness Rmax and the surface roughness Ra is specified by Rmax/Ra&#x2266;30.

Method of manufacturing a glass substrate and a magnetic recording medium

In a magnetic recording medium, surface roughness of a glass substrate and the variation of the surface roughness are suppressed. Namely, the surface roughness (Rmax, Ra, Rq) and the relation (Rmax/Ra) between Rmax and Ra are restricted. Ra is representative of a center-line mean roughness, Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point and Rq is representative of a root mean square roughness. Thereby, crystal grains of an underlying layer and a magnetic layer formed thereon are equalized. The surface roughness is specified by Rmax&lE;15 nm, Ra&lE;1 nm and Rq&lE;1.5 nm and the ratio between the surface roughness Rmax and the surface roughness Ra is in the range of 10 to 30.

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Akishima, Japan

Masao Takano