Electric heating – Metal heating – By arc
Reissue Patent
1999-08-13
2001-04-24
Heinrich, Samuel M. (Department: 1725)
Electric heating
Metal heating
By arc
C219S121680, C219S121820, C219S121650
Reissue Patent
active
RE037145
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to apparatus for fabricating a disk, such as a magnetic recording disk used in a computer hardfile, having a surface tenured by exposure to a pulsed laser, and, more particularly, to automated apparatus for moving a number of such disks through a station in which such texturing occurs.
2. Background Information
Current hardfile drives use a Contact Start-Stop (CSS) system allowing a magnetic head, used to read and write data, to contact the surface of a magnetic disk in a specific CSS region when the disk is stationary. Thus, before the rotation of a spinning disk has stopped, the magnetic head is moved to the CSS region, where the magnetic head settles on the surface of the disk. When the disk again starts to rotate, the magnetic head slides along the disk surface in this region, until the laminar air flow at the disk surface, due to its rotation, fully lifts the magnetic head from the disk surface.
After the magnetic head is lifted in this way, it is moved from the CSS region to another region of the disk to read and write data. The CSS region is preferably textured to minimize physical contact between the magnetic head and the disk surface. In this way, the contact stick-slip phenomenon often called “stiction” and other frictional effects are minimized, along with the resulting wear of the magnetic head surface. Outside the CSS region the remainder of the disk surface preferably retains a specular smoothness to permit high-density magnetic data recording.
3. Description of the Prior Art
U.S. Pat. No. 5,062,021, to Ranjan et al., describes a process in which magnetic recording media are controllably textured, particularly over areas designated for contact with data transducing heads. In conjunction with rigid disk media, the process includes polishing an aluminum nickel-phosphorous substrate to a specular finish, then rotating the disk while directing pulsed laser energy over a limited portion of the radius, thus forming an annular head contact band while leaving the remainder of the surface specular. The band is formed of multiple individual laser spots, each with a center depression surrounded by a substantially circular raised rim. The depth of the depressions and the height of the rims are controlled primarily by laser power and firing pulse duration. The shape of individual laser spots can be altered by varying the laser beam inclination relative to the disk surface. On a larger scale, the frequency of firing the laser, in combination with disk rotational speed controls the pattern or arrangement of laser spots. The smooth, rounded contours of the depressions and surrounding rims, as compared to the acicular character of mechanical textured surfaces, is a primary factor contributing to substantially increased durability of laser textured media.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, there is provided equipment for texturing a disk including a central round hole, a circular periphery, and flat, parallel sides. The apparatus includes a cassette, a lifter, an indexing mechanism, a laser, an optical system, a spindle, and a pick-and-place mechanism. The cassette includes a number of pockets, each of which is open at a first end to allow the insertion of a single such disk. Each pocket also includes a lifter access opening opposite the first end. The lifter is movable through the lifter access opening in a pocket to engage a disk within the pocket. The lifter moves the disk through the first end of the pocket to a first disk transfer point. The indexing mechanism moves the cassette adjacent the lifter, so that the lifter can be moved within each of the pockets. The spindle engages the disk at a second disk transfer point. The pick-and-place mechanism moves the disk from the first disk transfer point to the second disk transfer point. The laser produces a pulsed laser beam.
In accordance with another aspect of the invention, there is provided equipment for texturing a number of such disks. The apparatus includes a laser, a beamsplitter, a beam steering mirror, first and second disk-handling stations, and a shuttling mirror assembly. The laser produces a pulsed laser beam, which is divided by the beamsplitter into first and second sub-beams. Beam-steering mirrors direct these sub-beams to travel parallel to one another. Each disk-handling station includes an exposure station in which portions of the opposite sides of the disks are exposed to the sub-beams. The shuttling mirror assembly, which reflects the first and second sub-beams, is movable between a first position, in which the sub-beams are directed to travel toward the exposure station of the first disk-handling station, and a second position, in which the first and second sub-beams are directed to travel toward the exposure station of the second disk-handling station.
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Barenboim Michael
Baumgart Peter Michael
Chrusch Peter Paul
Karni Benjamin
Kerstens Pieter J. M.
Davidge Ronald V.
Heinrich Samuel M.
International Business Machines - Corporation
Tomlin Richard A.
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