Robert D Hempstead

US Patent:

6493191, Dec 10, 2002

Filed:

Sep 15, 1995

Appl. No.:

08/528890

Inventors:

William C. Cain - San Jose CA
Richard D. Anderson - Sunnyvale CA
Michael A. Baldwinson - Cupertino CA
Keith R. Berding - San Jose CA
Michael E. Devillier - San Jose CA
Garrett A. Garrettson - Los Altos Hills CA
Randolph S. Gluck - San Jose CA
Harold J. Hamilton - Santa Clara CA
Robert D. Hempstead - Los Gatos CA
Darren T. Imai - Los Gatos CA
Kwang K. Kim - Saratoga CA
Dimitre A. Latev - San Jose CA
Alexander P. Payne - Ben Lomond CA
David D. Roberts - Santa Cruz CA

Assignee:

Censtor Corporation - Los Gatos CA

International Classification:

G11B 5187

US Classification:

3602462, 3602461

Abstract:

A transducer for a hard disk drive system has a planar magnetic core and a pair of poletips that project transversely from the core for sliding contact with the disk during reading and writing. The transducer is formed entirely of thin films in the shape of a low profile table having three legs that slide on the disk, the poletips being exposed at a bottom of one of the legs for high resolution communication with the disk, the throat height of the poletips affording sufficient tolerance to allow for wear. The legs elevate the transducer from the disk sufficiently to minimize lifting by a thin air layer that moves with the spinning disk which, in combination with the small size of the thin film head allows a low load and a flexible beam and gimbal to hold the transducer to the disk. The transducer includes a loop shaped core of magnetic material that ends at the poletips, the core extending further parallel than perpendicular to the disk surface and preferably being formed of a plurality of slightly spaced ribbons of magnetic material in order to increase high frequency permeance. A high magnetic saturation layer may be formed adjoining the gap in at least the trailing poletip, in order to avoid saturation at the poletips during writing.

US Patent:

6535361, Mar 18, 2003

Filed:

Feb 28, 2001

Appl. No.:

09/795954

Inventors:

William C. Cain - San Jose CA
Michael E. Devillier - San Jose CA
Harold J. Hamilton - Santa Clara CA
Robert D. Hempstead - Los Gatos CA
Darren T. Imai - Los Gatos CA
Dimitre A. Latev - San Jose CA

Assignee:

Censtor Corp. - Los Gatos CA

International Classification:

G11B 539

US Classification:

3603181

Abstract:

A hard disk drive head operates in close proximity and dynamic contact with a rapidly spinning rigid disk surface, the head including a transducer with a magnetically permeable path between a poletip disposed adjacent to the disk surface and a magnetoresistive (MR) sensor situated outside the range of thermal noise generated by the surface contact. The magnetically permeable path is the same as that used to write data to the disk, eliminating errors that occur in conventional transducers having MR sensors at a separate location from the writing poletips. Moreover, the magnetically permeable path is preferably formed in a low profile, highly efficient âplanarâ loop that allows for manufacturing tolerances in throat height and wear of the terminal poletips from disk contact without poletip saturation or poletip smearing. The MR layer is formed in one of the first manufacturing steps atop the substrate, so that the MR layer has a relatively uniform planar template that is free from contaminants. A preferred embodiment has a laminated yoke for improved high frequency efficiency, with the MR element situated between the yoke lamina for improved sensitivity.

US Patent:

6671235, Dec 30, 2003

Filed:

Mar 27, 2000

Appl. No.:

09/536867

Inventors:

Andrew M. Hawryluk - Los Altos Hills CA
Robert D. Hempstead - Los Gatos CA
David A. Markle - Saratoga CA

Assignee:

Ultratech Stepper, Inc. - San Jose CA

International Classification:

G11B 1300

US Classification:

369 14, 369 1314, 369 1324

Abstract:

A method of, and apparatus for, defining disk tracks in magnetic recording media. The track-writing apparatus ( ) is capable of forming tracks ( ) with a track width (TW) and track spaces ( ) with a space width (SW) on a magnetic media disk ( ) having an upper surface ( S), wherein the disk comprises a magnetic medium with a thermal diffusion length (X). The apparatus comprises, in order along an optical axis (A ), a laser light source ( ) capable of providing a pulsed laser light beam (B ), a light pipe ( ), and illumination shaping optical system ( ) that provides substantially uniform illumination over an exposure region (ER), and a phase plate ( ) having a phase grating ( ) with a grating period (p), arranged proximate and substantially parallel to the upper surface of the disk so as to form an periodic irradiance distribution ( ) at the surface of the disk when the phase plate is illuminated with the exposure region. The irradiance distribution is capable of heating one or more regions of the disk to beyond the Curie temperature of the magnetic media. A method of defining the disk tracks using Spatial Period Division (SPD) with the track writing apparatus described above by forming closed annular demagnetized spaces in a periodic magnetized pattern ( ) formed in the disk is also disclosed.

US Patent:

7095585, Aug 22, 2006

Filed:

Oct 20, 2004

Appl. No.:

10/970782

Inventors:

Alexander P. Payne - Ben Lomond CA, US
William C. Cain - Foothill Ranch CA, US
Michael E. Devillier - San Jose CA, US
Harold J. Hamilton - Santa Clara CA, US
Robert D. Hempstead - Los Gatos CA, US
Darren T. Imai - Los Gatos CA, US
Dimitre A. Latev - San Jose CA, US
David D. Roberts - Fremont CA, US

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 5/147
G11B 5/235

US Classification:

360125, 360120

Abstract:

An information storage system includes a transducer having a loop of ferromagnetic material with pole tips separated by an nonferromagnetic gap located adjacent to a medium such as a rigid disk. During writing the separation between the pole tips and the media layer of the disk is a small fraction of the gap separation. Due to the small separation between the pole tips and the media layer, the magnetic field generated by the transducer and felt by the media has a larger perpendicular than longitudinal component, favoring perpendicular recording over longitudinal recording. The media may have an easy axis of magnetization oriented substantially along the perpendicular direction, so that perpendicular data storage is energetically favored. The transducer may also include a magnetoresistive sensor for reading magnetic information from the disk.

US Patent:

20020093761, Jul 18, 2002

Filed:

Nov 19, 2001

Appl. No.:

10/006453

Inventors:

Alexander Payne - Ben Lomond CA, US
William Cain - Foothill Ranch CA, US
Michael Devillier - San Jose CA, US
Harold Hamilton - Santa Clara CA, US
Robert Hempstead - Los Gatos CA, US
Darren Imai - Los Gatos CA, US
Dimitre Latev - San Jose CA, US
David Roberts - Fremont CA, US

International Classification:

G11B005/127

US Classification:

360/125000

Abstract:

An information storage system includes a transducer having a loop of ferromagnetic material with pole tips separated by an nonferromagnetic gap located adjacent to a medium such as a rigid disk. During writing the separation between the pole tips and the media layer of the disk is a small fraction of the gap separation. Due to the small separation between the pole tips and the media layer, the magnetic field generated by the transducer and felt by the media has a larger perpendicular than longitudinal component, favoring perpendicular recording over longitudinal recording. The media may have an easy axis of magnetization oriented substantially along the perpendicular direction, so that perpendicular data storage is energetically favored. The transducer may also include a magnetoresistive sensor for reading magnetic information from the disk.

US Patent:

59496126, Sep 7, 1999

Filed:

Aug 15, 1995

Appl. No.:

8/515140

Inventors:

Christopher S. Gudeman - Los Gatos CA
Michael H. Azarian - Cupertino CA
Michael A. Baldwinson - Cupertino CA
Keith R. Berding - San Jose CA
Kaynam Chun - San Francisco CA
Garrett A. Garrettson - Los Altos Hills CA
Harold J. Hamilton - Santa Clara CA
Robert D. Hempstead - Los Gatos CA
Dimitre A. Latev - San Jose CA
Mark A. Lauer - Pleasanton CA

Assignee:

Censtor Corp. - San Jose CA

International Classification:

G11B 0512

US Classification:

360 9701

Abstract:

A operationally contacting hard disk drive system has reduced friction due to lower capillary adhesion between the disk surface and a transducer in a substantially continuous sliding relationship with the surface. The disk surface has an adhesion-reducing texture that includes a microscopic RMS roughness in a range between about 1. 5 and 5. 5 nanometers, or a number of asperities having a mean plane to peak height in a range between about 6 and 50 nanometers. The roughness may increase in a radially graded fashion to compensate for the increased linear velocity and concomitant frictional power loss near the outer diameter of the disk. It is important that the uppermost reaches of the textured surface are smooth but not flat in order to obtain lasting low friction operation, which is accomplished by constructing the surface with a highest approximately one percent having an average radius of curvature in a range between 2 microns and 100 microns. An area of the slider in apparent contact with the disk surface is preferably less than 1000 square microns, and a ratio between this nominal area and the mean to peak height is less than 0. 3 meters. The slider may also include a substantial thickness of partially wetting material in contact with the disk, or may alternatively be textured with deep grooves or materials having differing wear rates, in order to provide reduced frictional adhesion despite wear of the slider.

US Patent:

42427100, Dec 30, 1980

Filed:

Jan 29, 1979

Appl. No.:

6/007274

Inventors:

Robert D. Hempstead - Morgan Hill CA
James B. Money - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 512
G11B 530

US Classification:

360113

Abstract:

A thin film inductive head is formed with nickel-iron binary alloy or nickel-iron-X ternary alloy pole pieces characterized by negative magnetostriction having a saturation magnetostriction coefficient in the range of -1. times. 10. sup. -6 to -5. times. 10. sup. -6.

US Patent:

61986070, Mar 6, 2001

Filed:

Oct 2, 1996

Appl. No.:

8/725296

Inventors:

William C. Cain - San Jose CA
Michael E. Devillier - San Jose CA
Harold J. Hamilton - Santa Clara CA
Robert D. Hempstead - Los Gatos CA
Darren T. Imai - Los Gatos CA
Dimitre A. Latev - San Jose CA

Assignee:

Censtor Corporation - San Jose CA

International Classification:

G11B 539

US Classification:

3603181

Abstract:

A hard disk drive head operates in close proximity and dynamic contact with a rapidly spinning rigid disk surface, the head including a transducer with a magnetically permeable path between a poletip disposed adjacent to the disk surface and a magnetoresistive (MR) sensor situated outside the range of thermal noise generated by the surface contact. The magnetically permeable path is the same as that used to write data to the disk, eliminating errors that occur in conventional transducers having MR sensors at a separate location from the writing poletips. Moreover, the magnetically permeable path is preferably formed in a low profile, highly efficient "planar" loop that allows for manufacturing tolerances in throat height and wear of the terminal poletips from disk contact without poletip saturation or poletip smearing. The MR layer is formed in one of the first manufacturing steps atop the substrate, so that the MR layer has a relatively uniform planar template that is free from contaminants. A preferred embodiment has a laminated yoke for improved high frequency efficiency, with the MR element situated between the yoke lamina for improved sensitivity.