David H Tung

US Patent:

6867949, Mar 15, 2005

Filed:

Jan 22, 2002

Appl. No.:

10/053934

Inventors:

Lin Guo - Milpitas CA, US
David M. Tung - Livermore CA, US
Xiaoping Hu - San Jose CA, US
Wei Guo - Fremont CA, US
Mark S. Seymour - Felton CA, US

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B005/55

US Classification:

3602656, 384611, 267136

Abstract:

The present invention is directed to a push-pin assembly for use with a positioning arm of a disk drive servo writer. The push-pin assembly promotes vibrational damping between the push-pin assembly and the actuator arm. Push-pin assemblies of the invention generally include a contact pin having a shaft and a contact head. The push-pin assembly also includes a body having a contact pin receptacle recessed into an end so that at least a portion of the contact pin shaft can be disposed in the receptacle. The contact head is thus disposed beyond the end of the body which includes the contact pin receptacle. The push-pin assembly additionally includes a vibration damper disposed between at least a portion of the contact pin shaft and the body.

US Patent:

6977790, Dec 20, 2005

Filed:

May 3, 2002

Appl. No.:

10/138035

Inventors:

Yih-Jen D. Chen - Milpitas CA, US
David M. Tung - Livermore CA, US
Lin Guo - Milpitas CA, US
Wei Guo - Fremont CA, US
Bill Wang - San Jose CA, US

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B021/02
G11B005/596

US Classification:

360 75, 360 7702, 360 7812, 3602941, 3602641, 360244, 2960303

Abstract:

An actuator arm assembly has an actuator arm and an actuator for moving the actuator arm whereby the arm assembly experiences vibrations. The actuator has a body with a recess formed therein, and a strain sensor is fitted essentially inside the recess such that the sensor generates signals correlated to the vibrations. This arrangement produces a high gain boost from the strain based sensor, making an amplifier circuit unnecessary. The sensor signals are used to damp the vibrations.

US Patent:

7050259, May 23, 2006

Filed:

Apr 18, 2002

Appl. No.:

10/125052

Inventors:

Lin Guo - Milpitas CA, US
David Tung - Livermore CA, US
Heng-Poh Khong - Singapore, SG

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B 21/02
G11B 5/596

US Classification:

360 75, 360 7703, 360 7804

Abstract:

A servo writer system for a disk drive uses the reader element of a magnetic transducer head in the disk drive to read head position information during servo writing of the disk drive. A positioning system in the servo writer uses both the head position information and actuator position information, as feedback signals to accurately position the transducer during servo writing, resulting in high quality servo tracks.

US Patent:

7050260, May 23, 2006

Filed:

Nov 12, 2002

Appl. No.:

10/293904

Inventors:

David M. Tung - Livermore CA, US
Lin Guo - Milpitas CA, US
Don Brunnett - Pleasanton CA, US

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A method and apparatus for partial self-servo writing a disk surface in a disk drive using servo wedge propagation is provided. In one embodiment, servo information is written by a servo track writer near an outer diameter of the disk surface. The servo information is grouped into a 1× set of servo information and a 2× set of servo information. The disk drive's read head is used to read the 1× set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 2× set of servo information. Then, the disk drive's read head is used to read the 2× set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 1× set of servo information. The process is repeated on a track-by-track basis until servo information is written from the outer diameter of the disk surface to the inner diameter of the disk surface, as if it was entirely written by a servo track writer.

US Patent:

7203019, Apr 10, 2007

Filed:

Oct 5, 2005

Appl. No.:

11/243815

Inventors:

Yanning Liu - Fremont CA, US
Yanchu Xu - San Jose CA, US
Michael McGrath - Pleasanton CA, US
David Tung - Livermore CA, US
Mark Heimbaugh - Pleasanton CA, US

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B 21/02
G11B 21/22
G11B 5/54
G11B 5/596

US Classification:

360 75, 360256, 3602562

Abstract:

A latch apparatus is configured to latch an actuator arm assembly that can position a read/write head relative to a data storage disk in a disk drive. The latch apparatus includes a latch arm, a coil, a permanent magnet, and a latch control circuit. The latch arm is configured to be moved between a closed position that inhibits movement of the actuator arm assembly in a landing zone and an open position that does not inhibit movement of the actuator arm assembly in the landing zone. The coil is configured to generate an electromagnetic force on the latch arm responsive to a coil current. The permanent magnet is configured to generate a magnetic force on the latch arm that is substantially opposed to the electromagnetic force from the coil. The latch control circuit is configured to increase according to defined open current profiles over a defined opening time period the coil current to at least an upper defined level to cause the coil to move the latch arm from the closed position to the open position. The latch control circuit is further configured to decrease according to defined close current profiles over a defined closing time period the coil current to no more than a lower defined level to cause the permanent magnet to move the latch arm from the open position to the closed position.

US Patent:

7355808, Apr 8, 2008

Filed:

May 23, 2006

Appl. No.:

11/439731

Inventors:

David M. Tung - Livermore CA, US
Lin Guo - Milpitas CA, US
Don Brunnett - Pleasanton CA, US

Assignee:

Maxtor Corporation - Scotts Valley CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A method and apparatus for partial self-servo writing a disk surface in a disk drive using servo wedge propagation is provided. In one embodiment, servo information is written by a servo track writer near an outer diameter of the disk surface. The servo information is grouped into a x set of servo information and a x set of servo information. The disk drive's read head is used to read the x set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the x set of servo information. Then, the disk drive's read head is used to read the x set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the x set of servo information. The process is repeated on a track-by-track basis until servo information is written from the outer diameter of the disk surface to the inner diameter of the disk surface, as if it was entirely written by a servo track writer.

US Patent:

8402303, Mar 19, 2013

Filed:

Apr 29, 2011

Appl. No.:

13/098281

Inventors:

Koichi Wago - Sunnyvale CA, US
Sundeep Chauhan - Fremont CA, US
David M. Tung - Livermore CA, US

Assignee:

Seagate Technology LLC - Cupertino CA

International Classification:

G06F 1/00
H04L 7/00

US Classification:

713503, 713400, 713401, 713500, 713501, 713600, 375303, 375305, 375334, 375336

Abstract:

The embodiments disclose a method for encoder frequency-shift compensation, including, determining frequency values of an input encoder signal, analyzing an encoder index clock signal and the input encoder signal to determine values of frequency-shifts and compensating for the values of the frequency-shifts to generate a frequency-shift compensated clock.

US Patent:

20070268618, Nov 22, 2007

Filed:

Apr 30, 2007

Appl. No.:

11/742347

Inventors:

Yanning Liu - San Ramon CA, US
Franz Dierkes - Los Gatos CA, US
David Tung - Livermore CA, US

International Classification:

G11B 5/596
G11B 21/02

US Classification:

360 7804, 360 75

Abstract:

Various methods and circuits are described for controlling movement of a read/write transducer. The acoustics that are generated when moving a read/write transducer are detected. Movement of the transducer is regulated in response to the detected acoustics.