Abstract: A stamper having a patterned layer composed of a hard material and a compressible material back plane layer. The back plane layer may be composed of an elastomer. The stamper may be used to imprint an embossable layer disposed above a substrate for the production of a magnetic recording disk.
Abstract: A method of forming a discrete track recording pattern on a soft magnetic underlayer of a perpendicular magnetic recording disk. In one embodiment, the soft magnetic underlayer is continuous throughout the discrete track recording pattern.
Type:
Grant
Filed:
October 27, 2006
Date of Patent:
October 27, 2009
Assignee:
WD Media, Inc.
Inventors:
David E. Wachenschwanz, Gerardo A. Bertero, David Treves, Andrew Homola, James L. Chao, Christopher H. Bajorek
Abstract: A method and apparatus is described for gradually transitioning a slider from operation over a patterned data zone to landing on a patterned CSS zone. The ratio of raised area width to recessed area width of a pattern in a transition zone and/or CSS zone may be varied across the radial dimension of the disk. By changing the ratio of raised area width to recessed area width of the pattern in the transition from slider operation over the data zone to landing in the CSS zone, it is possible to gradually change the height of the slider from flying to non-flying conditions.
Abstract: Methods to etch a workpiece are described. In one embodiment, a workpiece is disposed within an etchant solution having a composition comprising a dilute acid and a non-ionic surfactant. An electric field is generated within the etchant solution to cause an anisotropic etch pattern to form on a surface of the workpiece.
Abstract: A method of forming a discrete track recording pattern in a magnetic recording disk. In one embodiment, the discrete track recording pattern may be formed in a NiP layer continuous throughout the discrete track recording pattern. Alternatively, the discrete track recording pattern may be formed in a substrate.
Type:
Grant
Filed:
January 21, 2005
Date of Patent:
June 23, 2009
Assignee:
WD Media, Inc.
Inventors:
David E. Wachenschwanz, Gerardo A. Bertero, David Treves, Andrew Homola, James L. Chao, Christopher H. Bajorek
Abstract: A method for applying a strike voltage to one or more substrates during plating. During this method, the substrates are moved in a planetary manner while being held at their exterior edges by a set of parallel mandrels. (The substrates are held in a mutually parallel orientation, typically vertically, during plating.) A voltage is applied to the substrates via a contact pin, a contact plate, a set of ball bearings, a rack end-plate, and the mandrels.
Abstract: A magnetic recording system includes a patterned medium comprised of land areas and trough areas, a write element which writes the data to the patterned medium, and a read element which reads the data from the patterned medium and servo information from the troughs. The land areas store data and the trough areas inhibit storage of data. The read element is wider than the write element.
Type:
Grant
Filed:
June 7, 2004
Date of Patent:
December 30, 2008
Assignee:
WD Media, Inc.
Inventors:
David Wachenschwanz, Michael McNeil, John Vicars
Abstract: An optical test head comprises one or more detectors for providing output signals indicative of the condition of a workpiece surface. Data from these detectors are stored in one or more memories only when the data from the detectors satisfy one or more conditions (e.g. the data exceed than a particular threshold). The data are then passed from the one or more memories to an electrical circuit for processing. In addition, location information is stored in one or more memories and passed on to the electrical circuit when the data from the detectors satisfy the one or more conditions.
Abstract: An optical test head comprises one or more optical input paths by which a beam of light is communicated from a light source to a workpiece and one or more optical output paths by which light reflected off of the workpiece is communicated to a detector. The input optical path and the output optical path can include one or more mirrors and one or more lenses. At least one of the optical paths includes a layer for trapping and/or absorbing stray light. One or more of the lenses includes an anti-reflective coating for reducing noise caused by unwanted light reflection off of the lenses. The optical paths include one or more masks reducing stray light. The one or more masks can have an adjustable aperture (e.g. an iris).