Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2000-03-16
2002-10-15
Davis, David (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
Reexamination Certificate
active
06466408
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to a data storage system, and more particularly to a storage system slider having a trailing edge pad and method for making the same.
2. Description of Related Art
Conventional magnetic storage devices include a magnetic transducer or “head” suspended in close proximity to a recording medium, e.g., a magnetic disk having a plurality of concentric tracks. The transducer is supported by an air bearing slider mounted to a flexible suspension. The suspension, in turn, is attached to a positioning actuator. During normal operation, relative motion is provided between the head and the recording medium as the actuator dynamically positions the head over a desired track. The relative movement provides an air flow along the surface of the slider facing the medium, creating a lifting force. The lifting force us counterbalanced by a predetermined suspension load so that the slider is supported on a cushion of air. Air flow enters the leading edge of the slider and exits from the trailing end. The head resides toward the trailing end, which tends to fly closer to the recording surface than the leading edge.
The recording medium holds information encoded in the form of magnetic transitions. The information capacity, or areal density, of the medium is determined by the transducer's ability to sense and write distinguishable transitions. An important factor affecting areal density is the distance between the transducer and the recording surface, referred to as the fly height. It is desirable to fly the transducer very close to the medium to enhance transition detection. Some fly height stability is achieved with proper suspension loading and by shaping the air bearing slider surface (ABS) for desirable aerodynamic characteristics.
Another important factor affecting fly height is the slider's resistance to changing conditions. An air bearing slider is subjected to a variety of changing external conditions during normal operation. Changing conditions affecting fly height include, for example, change in the relative air speed and direction, and variations in temperature. If the transducer fly height does not stay constant during changing conditions, data transfer between the transducer and the recording medium may be adversely affected. Fly height is further affected by physical characteristics of the slider such as the shape of the ABS. Careful rail shaping, for example, will provide some resistance to changes in air flow.
Hard drive manufactures are starting to incorporate proximity recording type sliders in drives in order to achieve higher storage densities. The proximity recording slider is designed to maintain a small area near the read-write element in constant contact with the disk, and thus enabling smaller bit size and ultimately larger storage densities. This approach to increasing storage density puts considerable amount of strain on controlling wear at the slider-disk interface, because a slight variation in contact load and contact area could greatly affect the drive survivability.
Slider-disk contact results in lubricant depletion and degradation, wear of both surfaces, generation of wear particles, stick-slip, etc. All these phenomena affect magnetic performance of the disk drive, e.g., through jitter, as well as its durability. Nevertheless, as mentioned above, a contact slider is key for high-density magnetic recording.
Both, slider design and choice of material can minimize the negative effects of slider-disk contacts. For example, small contact pads on the slider minimize the contact area between slider and disk and decrease adhesion forces at the interface. Coating the ABS surface with a thin film of diamond-like carbon (DLC) decreases friction, increases wear resistance of both, slider and disk, reduces vibrations, etc.
Current products use carbon coatings of ca. 40 Å on the ABS (including a silicon sub-layer of about 10 Å to protect the MR element from corrosion. These 40 angstroms constitute 30% to 100% of the physical slider-disk separation for nominal slider designs with flying heights below 100 Å. In the future, it will be important to further decrease this spacing. However, the DLC layer is also needed to guarantee tribological characteristics of the slider. Slider DLC has proven to be a good tribological match for the disk carbon overcoat (COC). Therefor a thinner DLC layer will increase interfacial wear, friction, generation of wear particles, lube degradation, etc.
It can be seen that there is a need for a slider design with reduced DLC thickness while providing sufficient carbon-carbon contact at the disk-slider interface.
It can also be seen that there is a need for a storage system slider having a trailing edge pad and method for making the same.
SUMMARY OF THE INVENTION
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a storage system slider having a trailing edge pad and method for making the same.
The present invention solves the above-described problems by providing a trailing edge pad to provide a carbon-carbon contact between the storage medium surface and slider and by reducing the thickness of the DLC so that the magnetic spacing is reduced.
A method in accordance with the principles of the present invention includes forming a slider body having a first side, a second side, a leading edge and a trailing edge, forming air bearing surface on the slider body and forming a trailing edge pad at the trailing edge of the slider, wherein the trailing edge pad has a thickness that is greater than 10 &mgr;m to increase wear resistance of the trailing edge.
Other embodiments of a method in accordance with the principles of the invention may include alternative or optional additional aspects. One such aspect of the present invention is that the forming the air bearing surface further comprises forming a protective overcoat with decreased thickness over the air bearing surfaces.
Another aspect of the present invention is that the decrease in thickness of the protective overcoat corresponds to an increase in a magnetic spacing caused by the addition of the trailing edge pad to the slider.
Another aspect of the present invention is that the decrease in thickness of the protective overcoat is greater than the corresponding increase in a magnetic spacing caused by the addition of the trailing edge pad to the slider.
Another aspect of the present invention is that a protective overcoat is omitted.
Another aspect of the present invention is that the trailing edge pad provides the only carbon-carbon interface between the slider and the disk.
Another aspect of the present invention is that the trailing edge pad is formed only over a portion of the trailing edge, the trailing edge pad being positioned in alignment with a magnetic stripe of a magnetic head.
In another embodiment of the present invention, a slider having a carbon-carbon contact at a point where the slider interfaces with a disk includes a slider body having a first side, a second side, a leading edge and a trailing edge, an air bearing surface formed on the slider body and a trailing edge pad coupled to the slider at the trailing edge of the slider, wherein the trailing edge pad has a thickness that is greater than 10 &mgr;m to increase wear resistance of the trailing edge.
In another embodiment of the present invention, a system for storing and retrieving information, includes a magnetic disk, a motor, coupled to the disk, for rotating the disk, a recording surface, disposed on the magnetic disk, the recording surface dragging air as the disk rotates and creating an air flow in parallel with a tangential velocity of the disk rotation and a slider having a carbon-carbon contact at a point where the slider interfaces with a disk, the slider further includes a slider body having a first side, a second side, a leading edge and a trailing
Baumgart Peter M.
Hwang Cherngye
Khurshudov Andrei G.
Nguyen Son Van
Altera Law Group LLC
Davis David
LandOfFree
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