Slider with pressure relief trenches

Details Slider with pressure relief trenches Slider with pressure relief trenches

2001-01-16

2002-09-03

Tupper, Robert S. (Department: 2652)

Dynamic magnetic information storage or retrieval

Fluid bearing head support

Disk record

C360S237000

Reexamination Certificate

active

06445543

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a data storage system. In particular, the present invention relates to a slider with improved meniscus stiction control.
Disc drives are well known in the industry. Such drives use rigid discs coated with a magnetizable medium for storage of digital information in a plurality of concentric data tracks. Typically, disc drives include a disc pack including a plurality of concentric discs mounted on a spindle motor which causes the discs to spin. Heads carrying transducer elements are supported relative to the disc surfaces to read and or write digital information to the disc surfaces.
Heads include a slider supported via a suspension assembly coupled to an actuator or “E” block. Sliders include an air bearing surface which faces the disc surface. As the disc rotates, the disc drags air onto the slider along the air bearing surface in a direction approximately parallel to the tangential velocity of the disc. As the air passes beneath the air bearing surface, the pressure between the disc and the air bearing surface increases, which creates a hydrodynamic lifting force that causes the slider to lift directly above the disc surface to read and/or write data to the surface of the disc.
Prior to rotation of the disc, the slider rests on the disc surface. The slider is not lifted from the disc until the hydrodynamic lifting force, caused by rotation of the disc, is sufficient to overcome a preload force supplied to bias the slider toward the disc surface, and a stiction force holding the slider to the disc surface. The hydrodynamic properties of the slider are affected by the speed of rotation of the disc, the design of the air bearing surface of the slider, and the preload force supplied to the slider via the suspension assembly.
Typically a lubricant coating covers the disc surface to protect the slider and disc from wear during contact starts and stops (CSS). Contact between the slider and disc surface (and lubricant coating) creates a meniscus effect which increases stiction force between the slider and disc surface. When a disc drive is turned on, the spindle motor produces torque to overcome stiction and initiate “spin-up”. Stiction increases the motor torque required to spin-up the disc drive. If stiction is too large for motor torque to overcome, spin-up failure could occur.
Prior disc drives include both landing zones and data zones on the disc surface. The slider rests on the landing zone for CSS. The landing zone is textured to provide a roughened surface structure for reducing stiction between the slider and disc surface for take-off. However, the textured surface of the landing zone limits the fly-height of the slider. The present invention relates to these and other problems.
SUMMARY OF THE INVENTION
The present invention relates to a slider for supporting transducer elements for a data storage system including at least one pressure relief trench formed in the raised bearing surface proximate to a contact interface position between the slider and disc surface. The trench is sized to reduce capillary pressure of the meniscus relative to the disjoining pressure of a lubricant film layer on the disc surface to limit the area or expansion of a film bridge or meniscus between the bearing surface of the slider and disc surface.


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“A stiction Model for a Head-Disk Interface of a Rigid Disk Drive”, by J. Gui et al.,J. Appl. Phys., 78(6), pp. 4206-4217, Sep. 1995.
“Stiction Free Slider for the Smooth Surface Disk” by Y. Kasamatsu et al.,IEEE Transactions on Magnetics, vol. 31, No. 6, pp. 2961-2963, Nov. 1995.

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