Patent Application
20130148231
The present invention relates to magnetic data recording and more particularly to a suspension assembly having a protective feature for preventing contact between components of magnetic heads of adjacent suspension assemblies.
The heart of a computer is an assembly that is referred to as a magnetic disk drive. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension adjacent to a surface of the rotating magnetic disk and an actuator that swings the suspension to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). The suspension biases the slider into contact with the surface of the disk when the disk is not rotating, but when the disk rotates air is swirled by the rotating disk. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic impressions to and reading magnetic impressions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The write head can include at least one coil, a write pole and one or more return poles. When a current flows through the coil, a resulting magnetic field causes a magnetic flux to flow through the write pole, which results in a magnetic write field emitting from the tip of the write pole. This magnetic field is sufficiently strong that it locally magnetizes a portion of the adjacent magnetic disk, thereby recording a bit of data.
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor, or a Tunnel Junction Magnetoresisive (TMR) sensor can be employed to read a magnetic signal from the magnetic media. The sensor includes .a nonmagnetic conductive layer (if the sensor is a GMR sensor) or a thin nonmagnetic, electrically insulating barrier layer (if the sensor is a TMR sensor) sandwiched between first and second ferromagnetic layers, hereinafter referred to as a pinned layer and a free layer. Magnetic shields are positioned above and below the sensor stack and can also serve as first and second electrical leads so that the electrical current travels perpendicularly to the plane of the free layer, spacer layer and pinned layer (current perpendicular to the plane (CPP) mode of operation). The magnetization direction of the pinned layer is pinned perpendicular to the air bearing surface (ABS) and the magnetization direction of the free layer is located parallel to the ABS, but free to rotate in response to external magnetic fields. The magnetization of the pinned layer is typically pinned by exchange coupling with an antiferromagnetic layer. When the magnetizations of the pinned and free layers are parallel with respect to one another, scattering of the conduction electrons is minimized and when the magnetizations of the pinned and free layer are antiparallel, scattering is maximized. In a read mode the resistance of the spin valve sensor changes about linearly with the magnitudes of the magnetic fields from the rotating disk. When a sense current is conducted through the spin valve sensor, resistance changes cause potential changes that are detected and processed as playback signals.
In an effort to increase data density and thermal stability researchers have developed thermally assisted recording. At very small bit sizes, the magnetic bits on a media become inherently unstable. In order to prevent these very small bits from becoming inadvertently de-magnetized, the magnetic coercivity of the magnetic medium must be very high. However, if the magnetic coercivity is very high, the write head cannot record to the media. In order to overcome this, the slider can be equipped with a heating device, such as a laser, that can locally heat the media during recording. This temporarily lowers the coercivity so that the media can be recorded to. When the media cools, the high coercivity ensures that the recorded data remains stable.
However, the heating devices used to produce such localized heating are, necessarily, large. As such, they extend through the suspension assembly at a side opposite the slider. During a physical shock to the disk drive, there is a risk that the heating devices of adjacent sliders can contact one another, causing damage to one or both of the devices.
The present invention provides a suspension that includes, a suspension body having a first side and a second side opposite the first side, the suspension body being configured to hold a slider adjacent to the first side of the suspension body; and a protective structure extending from the second side of the suspension body.
The protective structure can be connected with a slider that has a heating element formed thereon. The heating element, being necessarily large, extends through an opening in the suspension to extend from the suspension at the side opposite the slider.
The protective structure is configured to protect the heating element from contacting other components of the disk drive system such as a heating element of another suspension assembly.
The protective structure can be formed at an angle relative to a longitudinal axis of the suspension to ensure that protective structures of adjacent suspensions contact one another in order to protect the heating elements of the suspension assemblies.
These and other features and advantages of the invention will be apparent upon reading of the following detailed description of preferred embodiments taken in conjunction with the Figures in which like reference numerals indicate like elements throughout.
For a fuller understanding of the nature and advantages of this invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings which are not to scale.
The following description is of the best embodiments presently contemplated for carrying Out this invention. This description is made for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts claimed herein.
Referring now to
At least one slider 113 is positioned near the magnetic disk 112, each slider 113 supporting one or more magnetic head assemblies 121. As the magnetic disk rotates, slider 113 moves radially in and out over the disk surface 122 so that the magnetic head assembly 121 can access different tracks of the magnetic disk where desired data are written. Each slider 113 is attached to an actuator arm 119 by way of a suspension 115. The suspension 115 provides a slight spring force which biases slider 113 against the disk surface 122. Each actuator arm 119 is attached to an actuator means 127. The actuator means 127 as shown in
During operation of the disk storage system, the rotation of the magnetic disk 112 generates an air bearing between the slider 113 and the disk surface 122 which exerts an upward force or lift on the slider. The air bearing thus counter-balances the slight spring force of suspension 115 and supports slider 113 off and slightly above the disk surface by a small, substantially constant spacing during normal operation.
The various components of the disk storage system are controlled in operation by control signals generated by control unit 129, such as access control signals and internal clock signals. Typically, the control unit 129 comprises logic control circuits, storage means and a microprocessor. The control unit 129 generates control signals to control various system operations such as drive motor control signals on line 123 and head position and seek control signals on line 128. The control signals on line 128 provide the desired current profiles to optimally move and position slider 113 to the desired data track on disk 112. Write and read signals are communicated to and from write and read heads 121 by way of recording channel 125.
While the view
In order to maximize data density while still ensuring writeability of the media, the data recording system can be constructed for thermally assisted recording.
The write head 304 can include a magnetic write pole 308, a magnetic return pole 310, and an electrically conductive, non-magnetic write coil 312. When current flows through the write coil, a resulting magnetic field causes a write field to be emitted from the tip of the write pole 308. This write field, which emits from the relatively small write pole 308 is dense and strong and writes to a magnetic recording layer of an adjacent magnetic medium (not shown in
As discussed above, in order to increase data density, the size of magnetic bits recorded on a magnetic medium must be reduced. However, when these magnetic bits become very small, they can be easily demagnetized, either by high temperature or simply becoming self demagnetized even at room temperature. One way to ensure the magnetic stability of the medium is to construct the magnetic medium with a very high magnetic coercivity. However, if the magnetic coercivity is high enough to ensure magnetic stability at very small bit sizes, it is also too high for the magnetic write head 304 to write to. The write head 304 cannot generate a sufficiently strong write field to overcome the high coercivity of the media, especially when the write pole must be made very small to record the very small bit size.
One way to overcome this obstacle is to use thermally assisted recording (TAR). Using TAR, the magnetic media is locally heating during magnetic recording. This temporarily lowers the coercivity of the magnetic media so that the magnetic write head 304 can write to the media. Thereafter, the media quickly cools, again raising the coercivity of the media and ensuring its magnetic stability.
In order to achieve this heating, the slider 113 is equipped with a thermal heating element such as a light source (e.g. laser) 320. A light delivery device 321 such as a fiber optic line extends through the slider 302 to deliver the light from the light source 320 to the ABS at a location preferably within the write head 304. An optical transducer 323 can be provided at the end of the light deliver device 321, at the ABS to focus the light and convert it to heat for heating the adjacent magnetic medium (not shown in
The present invention overcomes this problem, providing a structure that protects the heating element 320 and ensures that no contact between heating elements 320 of adjacent sliders 113 can occur.
As can be seen, the heating element 320 is so long that it actually extends through an opening in the suspension 115. In order to prevent the above contact between heating elements 320 of adjacent sliders 113, a protection structure 402 is formed on the suspension 115. The protective structure 402 can be integral with the suspension 115 and can be easily formed by cutting the material of the suspension 115 during manufacture and bending a tab of material upward as shown in
While various embodiments have been described above, it should be understood that they have been presented by way of example only and not limitation. Other embodiments falling within the scope of the invention may also become apparent to those skilled in the art. Thus, the breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
