Ellis Taeho Cha

US Patent:

6765758, Jul 20, 2004

Filed:

Nov 3, 1998

Appl. No.:

09/186212

Inventors:

Ellis T. Cha - San Jose CA

Assignee:

SAE Magnetics (H.K.) Ltd. - Hong Kong

International Classification:

G11B 560

US Classification:

3602361

Abstract:

An improved slider design is presented including first and second rails, where the rear portions of the rails have an angle greater than 0Â. Adjacent to an inside edge of at least one of the rails, a secondary structure is placed having a height less than that of the rails. Though subambient pressure is present between the first and second rails, the pressure is greater at the secondary structure. In one embodiment, the pressure at the secondary structure is less than one atmosphere over all diameters of the moving recording medium. The slider design of the present invention provides a âstifferâ air bearing, in that the slider resists changes due to gram loading to achieve a narrow distribution in flying height variations as well as roll and pitch variations.

US Patent:

6831814, Dec 14, 2004

Filed:

Jul 24, 1998

Appl. No.:

09/122472

Inventors:

Ellis T. Cha - San Jose CA

Assignee:

SAE Magnetics (H.K.) Ltd. - Kwai Chung

International Classification:

G11B 2116

US Classification:

3602453

Abstract:

A flexure design is provided that can focus the lifting force on a slider device at its leading edge. For sub-ambient pressure sliders, this results in an rapid increase in pressure in the sub-ambient pressure area causing the slider device to quickly lift off from the disk surface in a ramp unload disk drive. In one embodiment, first and second outriggers are provided in the flexure that each include a section that extends distally and a section that extends proximally. The sections of the outriggers that extend proximally can be joined and coupled to a tab section slider which would be located at the leading edge of the slider.

US Patent:

6943989, Sep 13, 2005

Filed:

Jun 7, 2002

Appl. No.:

10/165786

Inventors:

Ellis T. Cha - San Jose CA, US
Hao Qing Pan - Milpitas CA, US

Assignee:

Sae Magnetics (H.K.) Ltd. - Hong Kong

International Classification:

G11B005/60

US Classification:

3602362

Abstract:

A subambient pressure air bearing slider for disk drives and the like is presented where the subambient pressure area is divided into two or more areas. For example, a first area extending between the rails can have a depth (e. g. , between 20 and 100 microinches) relative to the height of the rails, while the second area has a deeper depth (e. g. , between 20 and 200 microinches). In one embodiment, the second area is placed in the outside rear quadrant relative to the rear edge of the slider and the rail closer to the outside diameter of the moving disk. By partitioning the subambient pressure area and properly selecting the depths of the partitioned areas, the slider can achieve a more uniform flying height over the range of diameters of the moving disk, at different rotational speed velocities for the disk and at different operation altitudes.

US Patent:

6989671, Jan 24, 2006

Filed:

Jan 14, 2003

Appl. No.:

10/342780

Inventors:

Li-Yan Zhu - San Jose CA, US
Xiaofeng Zhang - Fremont CA, US
Yen Fu - San Jose CA, US
Ellis T. Cha - San Jose CA, US

Assignee:

SAE Magnetics (H.K.) Ltd. - Hong Kong

International Classification:

G01R 33/12

US Classification:

324212, 360 7708, 324210

Abstract:

A method is described for calculating head disk interference (HDI) using a dynamic parametric test. In one embodiment, HDI is calculated based on an actual and ideal sensitivity profile based on a read-back signal track profile for the slider/head.

US Patent:

7042670, May 9, 2006

Filed:

Jul 11, 2003

Appl. No.:

10/618145

Inventors:

Zhu Feng - Pleasanton CA, US
Ellis Cha - San Ramon CA, US
David Hu - Los Altos CA, US
Yen Fu - San Jose CA, US

Assignee:

SAE Magnetics (H.K.) Ltd. - Shatin

International Classification:

G11B 5/60

US Classification:

360 75

Abstract:

A system and method for adjusting the flying height of a magnetic head above a magnetic storage medium, such as a disk, is disclosed. A charging electrical pad may be coupled to the slider separate from the magnetic head to allow a charging electrical conductor to apply an electrical charge to the slider. By acting as a quasi-parallel capacitor, the amount of spacing in the head-disk interface may be increased or decreased based on the amount of voltage applied. The slider may be electrically isolated from the suspension. A feedback control system may monitor and control the head-disk spacing by measuring temperature or other environmental conditions surrounding the slider and disk.

US Patent:

7046473, May 16, 2006

Filed:

Sep 14, 2004

Appl. No.:

10/941420

Inventors:

Yen Fu - San Jose CA, US
Ellis T. Cha - San Ramon CA, US
Zhu Feng - Pleasanton CA, US

Assignee:

SAE Magnetics (H.K.) Ltd. - Shatin

International Classification:

G11B 21/02

US Classification:

360 75, 3602344

Abstract:

A system and method for adjusting the flying height of a magnetic head above a magnetic storage medium, such as a disk, is disclosed. A charging surface of the slider, separate from the read/write head, allows a charging electrical interconnect to apply an electrical charge to the slider. By acting as a quasi-parallel capacitor, the amount of spacing in the head-disk interface may be increased or decreased based on the amount of voltage applied. The slider may be electrically isolated from the suspension. Simultaneously, a heating element deforms the slider to further adjust the spacing between the read/write head and the disk surface. A feedback control system may monitor and control the head-disk spacing by measuring a temperature or other environmental conditions surrounding the slider and disk.

US Patent:

7064928, Jun 20, 2006

Filed:

Apr 16, 2003

Appl. No.:

10/414233

Inventors:

Yen Fu - San Jose CA, US
Ellis Cha - San Ramon CA, US
Po-Kang Wang - San Jose CA, US
Hong Tian - Tai Po, HK
Manuel Hernandez - San Jose CA, US
Yaw-Shing Tang - Saratoga CA, US
Ben Hu - San Jose CA, US

Assignee:

Sae Magnetics (H.K.) Ltd. - Kwai Chung

International Classification:

G11B 5/55
G11B 5/60

US Classification:

3602345, 3602459

Abstract:

Method and apparatus are presented for electrically coupling a slider to ground. In one embodiment, a bonding pad is provided on a side of the slider body separate from the bonding pad(s) used for read/write signals. This separate bonding pad is electrically coupled within the slider body to components that are to be coupled to ground. A separate conductor provided on the suspension (e. g. , a trace, a flex circuit, etc. ) may be electrically coupled to the separate bonding pad via gold ball bonding. The conductor is also coupled to ground in the hard-disk drive device (e. g. , via the preamplifier). The use of the separated bonding pad and trace may negate the need to use a conductive adhesive to electrically ground the slider via its attachment to the tongue of a slider.

US Patent:

7085083, Aug 1, 2006

Filed:

Dec 5, 2003

Appl. No.:

10/728450

Inventors:

Li-Yan Zhu - San Jose CA, US
Chao-Hui Yang - Milpitas CA, US
Xiaofeng Zhang - Fremont CA, US
Yen Fu - San Jose CA, US
Ellis T. Cha - San Ramon CA, US

Assignee:

SAE Magnetics (H.K.) Ltd. - Shatin

International Classification:

G11B 27/36

US Classification:

360 31, 360 75

Abstract:

A system and method for testing the stroke and frequency response of a micro-actuator is disclosed. A dynamic parameter tester writes two concentric tracks on a noise free portion of a magnetic storage medium. A magnetic read/write head and a micro-actuator is positioned between the two concentric tracks. An initial oscillating voltage is applied at a first frequency to the micro-actuator while reading back a signal from the two concentric tracks. A stroke characteristic of the micro-actuator is calculated based in part on the read-back signal. The initial oscillating voltage is determined from previous tests. The first stroke characteristic of the micro-actuator is based on a time-averaged amplitude of the first signal. The two concentric tracks are written at a pre-determined pitch.