Patents Represented by Attorney Raghunath S. Minisandram
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Patent number: 6957511Abstract: Beginning with a smooth ground aluminum blank with a relatively thin layer of leveled Ni—P, circumferential electropolishing/texturing is carried out to achieve a smooth oriented surface. A conductive slurry is provided between the disc and a porous texturing tape which is in contact with a conducting plate or equivalent conductor. The disc serves as the anode, and the conducting plate as the cathode, while the slurry, being conductive, functions as an electrolyte. In the presence of current, a reverse electroplating occurs so that the Ni—P dissolves to form Ni2+, or nickel ions which are carried away by the conductive slurry. The conductive slurry further supports or carries therein abrasive material so that by moving the porous texturing tape past the disc surface, the texturing tape picks up the abrasive material in the slurry and simultaneously with the reverse electroplating, provides the desired mechanical abrasion to achieve texturing of the disc surface.Type: GrantFiled: November 13, 2000Date of Patent: October 25, 2005Assignee: Seagate Technology LLCInventors: Joseph Leigh, Connie Liu, David Kuo
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Patent number: 6944735Abstract: Method and apparatus for storing and retrieving copy-protected data within storage devices such as, for example, disc drives. Data that is to be copy protected is written on the storage device. A first data list, such as a manufacturer's storage device defect list, is copied and used to make a second data list. Then, the first data list is modified such that the area where the copy protected data is stored is identified as defective. Unless a request to read the copy protected data is received, the first data list is used and the copy protected data area is considered defective. However, if a request to read the copy protected data is received, the second data list is used and the copy protected data is read from its storage location.Type: GrantFiled: June 16, 2004Date of Patent: September 13, 2005Assignee: Seagate Technology LLCInventor: Gayle L. Noble
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Patent number: 6912795Abstract: A conical hydrodynamic bearing gauging and seating system that enables the efficient seating of conical hydrodynamic bearings to a rotor shaft and hub while the rotor assembly remains in a pressing fixture. The invention provides a conical hydrodynamic bearing gauging and seating apparatus comprising a capacitive probe assembly disposed within a hollow pressing fixture in communication with a rotor shaft.Type: GrantFiled: February 28, 2001Date of Patent: July 5, 2005Assignee: Seagate Technology LLCInventors: Michael D. Kennedy, Michael J. Whittome
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Patent number: 6908689Abstract: A magnetic recording medium containing a B-2 structured ruthenium-aluminum underlayer comprising a (200) crystallographic orientation with a thickness from about 50 ? to about 800 ?, and a magnetic layer with a Co(11.0) crystallographic orientation, and a method of making the same are disclosed. The medium deposited on mechanically textured and surface-oxidized NiP film has a relatively high remanent coercivity and a relatively high signal to medium noise ratio even at low OR-Mrt.Type: GrantFiled: December 20, 2001Date of Patent: June 21, 2005Assignee: Seagate Technology LLCInventors: Qixu Chen, Zhong Wu, Samuel D. Harkness, IV, Rajiv Y. Ranjan
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Patent number: 6904790Abstract: A system and method for characterizing and measuring hydrodynamic grooves made by ECM processes is disclosed. The method includes a procedure for alignment of the work piece to the measurement apparatus as well as a technique for accurately reliably measuring the erosion pattern quickly. Additionally, the invention provides a system for characterizing and measuring the erosion of these grooves.Type: GrantFiled: June 18, 2003Date of Patent: June 14, 2005Assignee: Seagate Technology LLCInventors: Mysore Venkatachalan Ananda, Steve G. Gonzalez, Christopher Rowe Hakes
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Patent number: 6903888Abstract: Defects of a hard disk drive servo pattern stamper are detected by comparing a scattered light beam pattern against the known servo pattern. A magnetic field is applied to stamper and the beam is linearly polarized. Variations in the physical offset of the beam, its scatter, are indicative of physical defects. Variations in the Kerr rotation of scattered beam are indicative of magnetic defects.Type: GrantFiled: January 15, 2003Date of Patent: June 7, 2005Assignee: Seagate Technology LLCInventors: Joseph Leigh, Nobuo Kurataka
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Patent number: 6898031Abstract: A system and method for replicating magnetic patterns on hard disk media includes a mask located over or above a magnetic recording layer. The recording layer may include a single, dual, or multi-layer recording layer. A pattern is or has been formed in the mask, where the pattern defines the recordable regions and the non-recordable regions to be created in one or more layers within the recording layer. Portions of the recording layer are then exposed. An etch may then be performed to create grooves within one or more layers in the exposed regions of the recording layer. The magnetic properties of at least one layer in the exposed portions of the recording layer are then altered in order to create recordable or non-recordable regions. The mask is then removed from the recording layer.Type: GrantFiled: April 19, 2001Date of Patent: May 24, 2005Assignee: Seagate Technology LLCInventors: Karl A. Belser, Neil Deeman, Ga-Lane Chen
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Patent number: 6898037Abstract: A method and apparatus for detecting a topographic feature on a media is described. More particularly, a light scatter detector is coupled to an atomic force microscope. The detector is used detect scattered optical energy reflected from the surface of the media to identify the topographic feature. The atomic force microscope may then be positioned in response to the topographic feature identified.Type: GrantFiled: November 27, 2001Date of Patent: May 24, 2005Assignee: Seagate Technology LLCInventors: Joseph Leigh, David S. Kuo
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Patent number: 6884330Abstract: The present invention relates to a method and apparatus for properly and consistently spacing an electrode from a workpiece while electrochemically etching (ECM) grooves to a precise depth in a surface of the workpiece to form a fluid dynamic bearing. The electrode is especially designed for imparting a grooved pattern to a flat surface, the electrode comprising a surface carrying the pattern to be formed on the flat surface, and a central rod extending a short distance above the electrode surface. The central rod precisely sets the gap between the electrode and the flat surface. The electrode is adapted to be electrically connected to a power supply so that the electrode serves as the cathode, and the flat work piece serves as the anode in an ECM system.Type: GrantFiled: October 24, 2001Date of Patent: April 26, 2005Assignee: Seagate Technology LLCInventor: Mark G. Steele
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Patent number: 6878418Abstract: A system and method for improving the durability and reliability of recording media used in hard drives is disclosed. A protective overcoat made by depositing a diamond like carbon (DLC) layer over a magnetic layer and then depleting a portion of the DLC protective layer of hydrogen before it is coated with a Perfluoropolyethers (PFPE) using an in-situ vapor lubrication technique. The portion of the DLC layer which is depleted can be data zone of the media so that the lubricant-bonding ratio is higher for the landing zone than it is for the data zone.Type: GrantFiled: March 27, 2003Date of Patent: April 12, 2005Assignee: Seagate Technology LLCInventors: Xiaoding Ma, Michael Joseph Stirniman, Jing Gui
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Patent number: 6874940Abstract: A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing is preloaded by an axially less stiff larger gap fluid dynamic bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, radially aligned with an air/gas filled spherical or conical or similar type bearing. A shaft end thrust bearing is also defined for axial support.Type: GrantFiled: April 10, 2003Date of Patent: April 5, 2005Assignee: Seagate Technology LLCInventors: Mohamed Mizanur Rahman, Gunter K. Heine
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Patent number: 6850388Abstract: Embodiments of the invention generally provide an apparatus and method for, sealing an outer surface of a shaft to an inner surface of a hub. In one embodiment, the invention provides a magnetic fluid seal held in a gap defined by a top member and a bottom member. In one aspect, the distance from the rotational axis of the shaft to the outer periphery of the lower member is less than the distance between the rotational axis of the shaft and the outer periphery of the upper member. In another aspect, the lower member has a member that slopes between a first radial distance to a second radial distance, relative the rotational axis of the shaft. In another aspect, the member has a stepped region including a first and second region where the first stepped region corresponds to a first radial distance, and the second stepped region corresponds to a second radial distance, relative the rotational axis of the shaft.Type: GrantFiled: February 5, 2002Date of Patent: February 1, 2005Assignee: Seagate Technology LLCInventor: Ralph James Knotts
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Patent number: 6850391Abstract: An injection molded plastic disc substrate incorporating a stiff insert made of a very stiff material (metal, ceramic, composite . . . e.g. silicon) embedded in the plastic matrix. Preferably, the insert has a circular center region and radially extending fingers. Additional features of the web may include one or more chordal connecting elements extending between the fingers. In this way, both vibration or flutter in the circumferential or radial direction is suppressed by the insert.Type: GrantFiled: March 9, 2000Date of Patent: February 1, 2005Assignee: Seagate Technology LLCInventor: Bruno J. Marchon
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Patent number: 6842747Abstract: Aspects of the invention include a method and apparatus to transfer data from a peripheral device directly to a disc drive storage system. In one aspect, the disc drive uses a transfer protocol that determines the types, sizes and data location structure for each file. In another aspect, the disc drive includes a file allocation table that stores the file location for the peripheral devices on the disc drive to increase the file transfer efficiency and speed.Type: GrantFiled: June 26, 2001Date of Patent: January 11, 2005Assignee: Seagate Technology LLCInventors: Gayle L. Noble, Rick S. Shimizu, Jason P. Hanlon
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Patent number: 6838227Abstract: A system and method for forming servo patterns on magnetic media is disclosed. A magnetic film coated with a layer of polystyrene is stamped with a nickel stamper reproducing the negative image of the stamped pattern on the polystyrene. Ions are then accelerated towards the surface of the polystyrene, which stopps the ions in the areas where the polystyrene is thick and allows the ions to penetrate through to the magnetic layer in the areas where the polystyrene is thin. The ions, which penetrate through to the magnetic layer, interact with the magnetic layer altering the magnetic layer's structure reducing its coercivity (Hc) and remnant moment (Mrt). This reproduces the stamped polystyrene pattern on the magnetic layer. The polystyrene is then removed by oxygen plasma etching the surface leaving behind a patterned magnetic media.Type: GrantFiled: March 29, 2002Date of Patent: January 4, 2005Assignee: Seagate Technology LLCInventors: HongYing Wang, Neil Deeman, Koichi Wago, Nobuo Kurataka
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Patent number: 6835290Abstract: A system and method for reducing and controlling the number of defects due to carbon inclusions on magnetic media is disclosed. A diamond like carbon protective layer is deposited on magnetic media using a rotary cathode target assembly. The target and cathode are cylindrical in shape and are mounted on holder that allows the target and cathode to rotate while holding a magnet fixed. The target surface is periodically swept in through a plasma which sputters off the surface of the target. This prevents the build up of redeposited material on the target and consequently keeps the target surface cleaner. The reduction of redeposited material on the target surface reduces the number of unwanted particulates which are ejected from the surface, manifesting themselves as disk defects.Type: GrantFiled: February 13, 2003Date of Patent: December 28, 2004Assignee: Seagate Technology LLCInventors: Jeffrey Shane Reiter, Stephen Eric Barlow, Zhiwei Cai
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Patent number: 6830600Abstract: A method for preventing migration of lubrication molecules into adjacent process chambers while coating a thin layer of lubricant over a storage surface of a disc using a vapor lubrication process. The method includes trapping the lubrication molecules that are not deposited onto the storage surface of the discs during the vapor lubrication process by using one or more cold traps including cold trapping surfaces in a vapor lubrication station.Type: GrantFiled: April 12, 2001Date of Patent: December 14, 2004Assignee: Seagate Technology LLCInventors: Paul Stephen McLeod, Michael Joseph Stirniman, Jing Gui
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Patent number: 6824896Abstract: A magnetic media structure 200 deposited on glass substrates without a NiP layer having oriented media (ORMRT>1), high coercivity and high SMNR is presented. This media will significantly reduce the cost of making high quality media on glass substrates by eliminating the cost associated with additional steps of depositing a NiP layer and texturing that layer. First glass substrates are mechanically textured to have a surface roughness of about 1 Å to about 12 Å. The first layer of the magnetic structure contains Cr and Ti with a Ti content of 27 to 63 atomic percentage. The second layer contains Co and Ti with a Ti content of 43 to 55 atomic percentage. The third layer is a Cr-alloy layer wherein the alloy is an element chosen from W, Mo, V, Si, Ti, Mn, Ru, B, Nb, Ta, Zr, and Pt. The fourth layer is Co58Cr37Pt5 and the fifth layer is Co61Cr15Pt12B12. Finally, the protective overcoat is typically a hard material that contains hydrogenated carbon.Type: GrantFiled: December 31, 2002Date of Patent: November 30, 2004Assignee: Seagate Technology LLCInventors: Li-Lien Lee, Samuel Dacke Harkness, Kien Vinh Hua, Eric Steck Freeman
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Patent number: 6819023Abstract: A circular magnetizer is disclosed comprising circular insulating inset holding pans of axially disposed wires, each pair carrying a current oppositely directed from the adjacent pair, the insert being disposed within and facing a back iron across a circular gap of sufficient width to allow a circular magnet to be disposed therein and spaced by a gap from the insert and/or back iron. The pan's of wires are arranged to create flux lines which will establish alternating magnetic poles separated by null zones in the magnet.Type: GrantFiled: August 2, 2000Date of Patent: November 16, 2004Assignee: Seagate Technology LLCInventors: Donald J. MacLeod, Greg Zariphopoulos, Robert M. Pelstring, Alain Cassat, Gunter Karl Heine
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Patent number: 6817767Abstract: A bearing system in which an axially stiff narrow gap fluid dynamic gas bearing. As an example two fluid dynamic bearings are provided spaced apart along a shaft, one of the bearings comprising a fluid dynamic bearing, the other comprising an air bearing. The fluid dynamic bearing has a larger gap, while the air bearing has a relatively small gap. The overall working surface area of the air bearing may be twice as much or more than the working surface area of the fluid bearing.Type: GrantFiled: June 28, 2002Date of Patent: November 16, 2004Assignee: Seagate Technology LLCInventors: Michael David Kennedy, Mohamed Mizanur Rahman, Hans Leuthold