Patent Publication Number: US-2002006083-A1

Title: Disc drive suspension and head

Description:
FIELD OF THE INVENTION  
       [0001] The present invention is in the field of disc drive mechanisms for reading data from and writing data to data storage discs. More particularly, the present invention is in the field of magneto-optical (MO) disc drives.  
       BACKGROUND OF THE INVENTION  
       [0002] Electronic data is commonly stored on discs of various types. Disc drives hold and rotate the disc while positioning a mechanism over the disc to read data from it or write data to it. Some conventional disc drives use a “flying” read/write head, or “flying head”, to access data stored magnetically on circular or spiral grooves, or tracks, of the data storage disc. Engaging the flying head in a position to access data is referred to as loading the head. Typically, the flying head is positioned over a track at a certain height to allow data reading or data writing. For example, in magneto-optical (MO) disc drives, data is recorded by positioning a head that includes a magnetic coil in proximity to an MO disc, locally heating the MO disc to lower the coercivity of a layer of magnetic media. When the coercivity of the magnetic media is lowered, the magnetic head applies a magnetic field to reverse the magnetic polarity in the heated area recording data on the MO disc. In such MO disc drives, data is read from the magnetic media of the MO disc by illuminating areas of the MO disc with linearly polarized laser light. The Kerr rotation effect causes the plane of polarization of the illuminating laser beam to be rotated. The direction of rotation depends on the magnetic polarity in the illuminated area of the storage media. When the MO disc is read, the polarization rotation is determined with a pair of optical detectors in a polarization beam splitter to produce an output data signal.  
       [0003] In one prior art method, a flying head is in a loaded position on the MO disc when it is not spinning and no data access operation is taking place. For a data access operation, the MO disc is rotated so that an air bearing forms between the MO disc and the flying head. When the flying head is suspended above the MO disc by the air bearing, the flying head can be moved over the MO disc to an appropriate area to perform a data access operation. This technique is referred to as static loading and unloading or as contact-start-stop because the MO disc must be stationary when the head is loaded or unloaded. This technique has several disadvantages. One disadvantage is that part of the MO disc area must be set aside as a landing zone, which reduces the MO disc area available for data storage. Another disadvantage is that the head can crash into the MO disc if the drive is bumped or dropped, if power is suddenly removed from the drive, or if contaminants are on the disc surface at loading and become trapped under the head. When the head crashes into the MO disc, there is a likelihood of damage to the MO disc, loss of data stored on the MO disc, and even destruction of the drive itself.  
       [0004] Yet another disadvantage of prior art static loading/unloading systems is the necessity of providing a very smooth, very flat, slider surface and media surface on which to carry the magnetic head. Such a slider body is needed in static loading/unloading systems to withstand thousands of contact-start-stop events in the life of the disc drive. In addition, static loading/unloading systems also require lubrication and texturing of the media surface.  
       [0005] Another prior art method, called dynamic loading and unloading, loads and unloads the head while the MO disc is spinning. FIG. 1 is a diagram of a some parts of a prior art disc drive that performs dynamic loading and unloading. Suspension  103  is attached to flying head  109 . Suspension  103  is typically manufactured of a material with spring characteristics and has a bend  105  created by forming the material of suspension  103 . Bend  105  serves the purpose of providing a spring force and stiffness in the direction perpendicular to the surface of MO disc  107 . Some other prior art suspensions may include multiple bends. The angle of bend required to produce the appropriate spring force required in a particular disc drive application must be calculated before forming suspension  103 . Because the forming process is imprecise, some trial and error may be required to produce a suspension having the required spring force. Typically, the gram load of the suspension is measured after the suspension if formed.  
       [0006] Flying head  109  is loaded by moving suspension  103  over ramp  101 . The surface of ramp  101  over which suspension  103  moves has a slope such that suspension  103  and flying head  109  are moved over MO disc at the proper height for read or write operations. When suspension  103  is advanced toward disc  107 , suspension  103  is flexed such that the angle of bend  105  is opened.  
       [0007]FIG. 2 is a side view of suspension  103  and flying head  109  showing bend  105 . Mounting plate  111  is attached to suspension  103  and to mounting area  113 . Actuator arm  113  is a rigid part of the disc drive assembly. Plane  115  is the plane of an MO disc drive in the disc drive assembly incorporating suspension  103 . When head  109  is loaded, suspension  103  is flexed, for example by ramp loading as in FIG. 1, so that the surface of head  109  is approximately parallel to plane  115 .  
       [0008] Disadvantages of prior art suspension systems include the time and expense required to form a bend in the suspension and test the suspension to confirm that it has the appropriate spring force.  
       SUMMARY OF THE INVENTION  
       [0009] A magneto-optical (MO) disc drive including a novel suspension, slider body, airbearing surface, and magnetic head is described. The MO disc drive includes a fine-focus actuator block including an objective lens, wherein the coarse carriage block moves radially above a surface of an MO disc to position the objective lens. The MO disc drive also includes a flat suspension having a first end and a second end, wherein the first end is fixedly attached to the fine-focus actuator block and the second end is attached to the coarse carriage block. A gimbal is moveably attached to an opening in a surface of the suspension and a magnetic head assembly is attached to the gimbal. The magnetic head assembly is loaded and unloaded by the load/unload mechanism independent of the objective lens and attached to the coarse actuator.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010]FIG. 1 is a diagram of a prior art ramp loading mechanism.  
     [0011]FIG. 2 is a diagram of a prior art magnetic head suspension assembly.  
     [0012]FIG. 3 is a diagram of one embodiment of a head/suspension/fine-focus actuator assembly.  
     [0013]FIG. 4 is a diagram of one embodiment of a magnetic head suspension assembly.  
     [0014]FIG. 5 is a diagram of another embodiment of a magnetic head suspension assembly.  
     [0015]FIG. 6 is a diagram of another embodiment of a magnetic head suspension assembly.  
     [0016]FIG. 7 a  is a top view of a magnetic write coil.  
     [0017]FIG. 7 b  is a cross-section view of a magnetic write coil.  
     [0018]FIG. 8 a  is a diagram of an embodiment of a suspension.  
     [0019]FIG. 8 b  is a diagram of another embodiment of a magnetic head and suspension assembly.  
     [0020]FIG. 9 is a diagram of one embodiment of a load/unload mechanism in a position required to load a magnetic head.  
     [0021]FIG. 10 is a more detailed diagram of one embodiment of a load/unload mechanism.  
     [0022]FIG. 11 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0023]FIG. 11 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 11 a.    
     [0024]FIG. 12 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0025]FIG. 12 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 12 a.    
     [0026]FIG. 13 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0027]FIG. 13 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 13 a.    
     [0028]FIG. 14 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0029]FIG. 14 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 14 a.    
     [0030]FIG. 15 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0031]FIG. 15 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 15 a.    
     [0032]FIG. 16 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0033]FIG. 16 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 16 a.    
     [0034]FIG. 17 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0035]FIG. 17 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 17 a.    
     [0036]FIG. 18 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0037]FIG. 18 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 18 a    
     [0038]FIG. 19 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0039]FIG. 19 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 19 a    
     [0040]FIG. 20 a  is diagram of one embodiment of a slider body and airbearing surface.  
     [0041]FIG. 20 b  is a cross-sectional view of the slider body and airbearing surface of FIG. 20 a.    
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION  
     [0042] The present invention includes a disc drive with a novel magnetic head and an intelligent load/unload mechanism. In one embodiment, the present invention includes a magneto-optical (MO) disc drive for reading from and writing to a magneto-optical MO disc. The present invention may be used with a magneto-optical recording apparatus and method as described in co-pending U.S. patent application Ser. Nos. 09/027,420 and 09/026,798, both entitled Method and Apparatus for Reading and Writing Magneto-Optical Media, which are assigned to the Assignee of the present patent application.  
     [0043]FIG. 3 is a diagram of fine-focus actuator block  114  and magnetic head suspension assembly  110  according to one embodiment. In the embodiments described, the reading and recording technique used is a magneto-optical technique. Embodiments of the present invention could, however, be used with other recording techniques. Fine-focus actuator block  114  is attached to a coarse carriage (not shown). Fine-focus actuator block  114  includes a fine actuator, a focus actuator and an objective lens in its interior  115 . The objective lens focuses laser light that travels in the direction of arrow  116  toward an MO disc (not shown) while a read or write operation to the MO disc takes place. The focus actuator moves the objective lens in the direction  116  to maintain focus. The fine actuator moves the objective lens in the direction  120  to maintain fine positioning. When an MO disc is in place, it rotates in the a plane parallel to the surface of slider body  106  and fine-focus actuator block  114  (along with a coarse actuator which is not shown) moves laterally, as shown by arrow  120 , in order to position the objective lens and flying slider body  106  above an appropriate area of the MO disc. Suspension  110  includes mounting plate  104  that is bonded or screwed to fine-focus actuator block  114 . Suspension arm  110  is made of a flexible material such as stainless steel or copper, and the end of suspension arm  110  that is opposite mounting plate  104  is free to be moved up and down by load/unload mechanism  112 . Load/unload mechanism  112  is explained more fully below. Suspension  110  holds a flying magnetic head that includes slider body  106  and magnetic coil  108 . Magnetic coil  108  and slider body  106  face an MO disc in a completely assembled MO disc drive. When suspension  110  is not in contact with load/unload mechanism  112 , suspension arm  110  is in a loaded position with respect to an MO disc. In one embodiment, as shown in FIG. 3, magnetic coil  108  forms a light channel through which laser light passes to an MO disc from an objective lens in fine-focus actuator body  115 . Fine-focus actuator body  115  includes a fine actuator for fine tracking and a focus actuator for focusing laser light through the objective lens after fine-focus actuator block  114  is moved over a track by the coarse carriage. The fine actuator moves radially with respect to the MO disc and the focus actuator moves perpendicularly with respect to the MO disc. The objective lens is attached to the fine and focus actuators and is decoupled from the magnetic head assembly attached to suspension  110 .  
     [0044]FIG. 4 is a diagram showing an embodiment of a suspension. Suspension  110  is shown with mounting plate  104  and tab portion  202 . Tab portion  202  contacts load/unload mechanism  112  during unload operations. Gimbal area  118  is shown with outer gimbal portion  118 A (for enabling slider pitch) and inner gimbal portion  118 B (for enabling slider pitch). Gimbal area portions  118 A and  118 B each pivot about an axis that is parallel to the surface of an MO disc in the assembled disc drive. In the embodiment shown, gimbal assembly  118  is circular, but in other embodiments, the gimbal assembly could have other shapes, such as a rectangular shape. The axes of rotation of gimbal portions  118 A and  118 B are perpendicular to each other. The inner radius of gimbal portion  118 B receives slider body  106 . Slider body  106  includes a flange portion (not shown) that is sized to fit into gimbal portion  118 B, making slider body  106  and gimbal assembly  118  self-aligning. This arrangement makes assembly easier and more efficient as compared to the prior art. In prior art assemblies, a magnetic head assembly such as is formed by slider body  106  and magnetic coil  108  is bonded to a flat surface of a gimbal assembly. In such prior art arrangements, alignment and/or measurement is necessary before bonding the gimbal assembly to the magnetic head assembly in order to match the x and y axes of the gimbal assembly to those of the magnetic head assembly.  
     [0045] Slider body  106  includes a step  205  in its inner radius. Step  205  receives magnetic coil  108 , which is bonded to the flat surface of step  205 . In one embodiment the inner diameter of magnetic coil  108  forms the inner diameter of the assembly of magnetic coil  108  and slider body  106 . This inner diameter defines a channel for laser light. In one embodiment, the inner diameter of magnetic coil  108  is approximately 0.16 mm. Wire  204  is a magnetic coil that in one embodiment has approximately 25 turns. Wire  204  is made of any material typically used for such a purpose such as copper or aluminum wire. In one embodiment, magnetic coil  108  has a relatively fast current rise time of less than three nanoseconds.  
     [0046] The assembly formed by magnetic coil  108 , slider body  106 , suspension  110  is more easily assembled to the fine-focus actuator block than suspension arms of the prior art. Prior art suspension arms are typically screwed or swaged to the appropriate part of the disc drive. In the present invention, clip portion  104  of suspension arm  110  snaps onto coarse carriage block  114  and is retained thereon by spring tension.  
     [0047]FIG. 5 is a diagram of suspension  110  as assembled. FIG. 5 shows the side of suspension  110  and its connected components that face away from an MO disc in an assembled drive. FIG. 5 shows gimbal assembly portion  118 A, as well as slider body  106  seated in gimbal portion  118 B.  
     [0048]FIG. 6 is a diagram of another embodiment of a suspension and magnetic head (as also shown in FIG. 3). Suspension  501  includes gimbal assembly  507 , which has an opening to accommodate magnetic head  503 . Magnetic head  503  is rectangular and includes leading edge chamfer, or ramp  513  for forming an air bearing when an MO disc spins in proximity to magnetic head  503 . Coil  505  seats in the opening of magnetic head  503 .  
     [0049] Suspension  501  attaches to a disc drive assembly through screws or bolts in holes  511 . Ears  509  may be used to align suspension  501  with the disc drive so that laser light may travel through the opening in coil  505  as required during read and write operations.  
     [0050]FIG. 7 a  is a top view of an embodiment of a coil  507 . The oval shape of coil  507  results in lower inductance. FIG. 7 b  is a cross-section view of coil  507 . Coil  507  is wound to form a conical cross-section as shown. Laser light enters coil  507  through the wider part of the opening formed by the windings of coil  507 . As electric current travels through coil  507 , magnetic flux is induced in the center of coil  507  in a direction that is perpendicular to the surface of an MO disc. Because the cross-section of coil  507  is conical in cross-section rather annular, as in the typical prior art, the windings of the coil are closer to the focal point of the laser light than in prior art systems. This results in increase in the amount of flux produced for amount of inductance or the amount of clearance between the laser light and the coil. The wire is approximately 56 gage wire and the wire has approximately 25 turns.  
     [0051]FIG. 8 a  is a diagram of one embodiment of suspension. Suspension  805  is one flat piece of material. Magnetic head  807  may be any of the embodiments described herein. When assembled in a disc drive, mounting plate  809  is attached to mounting area  811  of the disc drive so that the facing surfaces of mounting plate  809  and mounting area  811  are in rigidly held in contact. When assembled, suspension  805  forms an angle with plane  817  and a gram load is generated. Therefore, the present invention provides for gram load generation without the requirement of pre-forming the suspension and testing for proper spring force as in the prior art.  
     [0052] The angle of mounting plate  809  is calculated from the required spring force. For example, known computer programs that perform finite element analysis may be used for this purpose. Once the angle is determined, however, the spring force, or stiffness in the direction vertical plane  817  is guaranteed by design. This is in contrast to the prior art, wherein even after bend locations and angles for the suspension have been determined and tested, variances introduced by the forming process and possibly by material make further process verification testing necessary.  
     [0053]FIG. 8 b  is a diagram of another embodiment of a suspension. Suspension  805  as in FIG. 8 a  is shown. The angle between suspension  805  and plane  817  is formed, in this embodiment, by mounting plate  813  is attached to angled mounting area  815  of the disc drive.  
     [0054]FIG. 9 is a diagram of load/unload mechanism  112  showing suspension  110  in a loaded position. Load/unload mechanism  112  is mounted on fine focus actuator block  114 . Arm and engagement pin mechanism  504  rotates about a stationary pin. When arm and engagement pin assembly  504  rotate and contact tab  202 , suspension arm  110  is pulled away from a magneto-optical disc, and the flying magnetic head seated in suspension  110  is unloaded. When engagement arm and pin assembly  504  is not in contact with tab  202 , the flying magnetic head is free to fly above the MO disc at a height appropriate for write operations. Load/unload mechanism  112  is actuated by a rotary moving coil and fixed magnet actuator. In other embodiments, the actuator may be a rotary moving magnet and fixed coil actuator.  
     [0055] The operation of load/unload mechanism  112 , as well as the rest of the disc drive in which the assembly resides is controlled by a microprocessor in the disc drive. Load/unload mechanism  112  includes anchor pin  508  and moving pin  506 . Moving pin  506  and anchor pin  508  and fixed pin  512  are connected by spring  514 . When the flying magnetic head is loaded or unloaded, torque is applied to plate  502 , which overcomes the retaining torque supplied by spring  514  so that arm and engagement pin  504 , moving pin  506  and plate  502  rotate. In the position shown, the flying magnetic head is loaded and the retaining torque supplied by spring force of spring  514  maintains load/unload mechanism  112  in the position shown. When it is required to unload the flying magnetic head, torque applied to plate  502  rotates moving pin  506 , engagement pin  504  and plate  502  clockwise such that the spring force of spring  514  is overcome and plate  502  rests against stops (not shown) and is held in place by spring force of spring  514 . Once in the unloaded position, spring force of spring  514  retains the assembly in the new, unloaded position. Because spring force is used to maintain load/unload mechanism  112  in either the loaded or unloaded position it is not necessary to use electrical energy to maintain the magnetic head in either the loaded or unloaded position.  
     [0056] The present invention has the significant advantage of loading or unloading the flying magnetic head to or from any position on a disc. The microprocessor of the disc drive controls operations of load/unload mechanism  112  such that under fault conditions, the flying magnetic head is unloaded regardless of position on the disc. Such fault conditions include sudden loss of power to the drive or significant contaminants on the disc surface. When main power to the drive is suddenly interrupted, capacitively stored power is used to unload the flying magnetic head. In another embodiment, the spindle motor turning the MO disc has sufficient back electromagnetic force (EMF) to unload the flying magnetic head before the disc stops spinning. With the present invention, the danger of the magnetic head physically crashing into the disc is virtually eliminated. In addition, in contrast to contact-stop-start methods of loading and unloading it is not necessary to dedicate an area of the disc as a landing zone. For this reason, the entire disc can be used for data storage and overall data storage density is increased. Additionally, contact-start-stop requires lubrication on the disc surface. Lubrication is expensive and evaporates over time.  
     [0057] In the present invention, the objective lens (covered by fine-focus actuator block  114 ) is decoupled from the flying magnetic head that is mounted in gimbal assembly  118 . Because the magnetic head is used only for writing, it is possible to scan the disc using only the objective lens without loading the magnetic head. This has the advantage of allowing a scan of pre-embossed information before performing a load of head, thereby eliminating the possibility of crashing the head onto the drive when the disc is of a wrong type or the disc is contaminated such that it is not possible to read pre-embossed information on the disc. The pre-scan of pre-embossed information should indicate such problems and prevent loading of the magnetic head under potentially hazardous conditions.  
     [0058]FIG. 10 is a diagram of elements beneath plate  502  of load/unload mechanism  112 . FIG. 10 shows arm and engagement pin  504 , moving pin  506 , anchor pin  508 , moving coil  702 , and fixed magnet  704 .  
     [0059]FIG. 11 b  is a top view of an embodiment of a slider body of a magnetic head. Slider body  800  is an alternative embodiment to the embodiment of slider body  106 . Slider body  800  is rectangular in shape, and is approximately 5.5 mm long and approximately 3.5 mm wide. FIG. 11 b  shows the surface of slider body  800  that faces an MO disc. Slider body  800  includes a raised positive pressure airbearing surface in peripheral area  802  and recessed relieved pressure central area  806 . Raised peripheral area is approximately one mm in width. When a disc is spinning over slider body  800  air travels, in the direction shown by arrow  816 . As air strikes leading edge  818 , loose surface contaminants are knocked off of the MO disc before the MO disc passes under slider body  800 . This is in contrast to typical prior art flying magnetic heads in which the slider body includes a leading edge ramp, which is required to generate pressure in a contact-start-stop application. It is not necessary in the present invention to have a leading edge ramp, because even when the head is unloaded and the disc is not spinning, slider body  800  never contacts the disc. In this embodiment, slider  800  has a light channel  810  through the entire body. Additionally, the airbearing surface  802  is not connected across edge  818 . Step  808  in light channel  810  provides a bonding seat for a magnetic coil inserted in slider body  800 . The magnetic coil surface is coplanar with air bearing surface  802 .  
     [0060]FIG. 11 a  is a cross-section of slider body  800 . The cross-section shows seat  808  for bonding a magnetic coil. The cross-section also shows flange  814 , which is sized to fit into a circular gimbal assembly such as gimbal assembly  118 . In this embodiment, bevel  812  connects flange  814  with seat  808  adjacent to light channel  810 .  
     [0061]FIG. 12 b  is a diagram of another alternative embodiment of a slider body. Slider body  900  is rectangular in shape, and of approximately the same dimensions as slider body  800 . Slider body  900  includes pressure relieved central recessed area  906 . Slider body  900  also includes a raised positive pressure peripheral area  902  around the entire perimeter of slider body  900 . The width of raised peripheral area  902  is approximately one mm. Slider body  900  includes light channel  910  therethrough, and step  908 . Step  908  forms the inner diameter of light channel  910  and provides a bonding ledge for a magnetic coil. In some embodiments, air may travel in the direction of arrow  916   a  when slider body  900  is in operation. In other embodiments, air may travel in a direction indicated by  916   b  when slider body  900  is in operation.  
     [0062]FIG. 12 a  is a cross-sectional view of slider body  900  showing flange  912 , step  908 , and bevel  912 .  
     [0063]FIG. 13 a  shows another embodiment of a slider body. Slider body  1000  includes light channel  1010 , step  1008  in write channel  1010 , and raised positive pressure airbearing surfaces  1002  and  1003 . Raised surfaces  1002  and  1003  are approximately one mm wide. The diameter of light channel  1010  is approximately one mm. The width of step  1008  is approximately 0.2 mm. In one embodiment, air flows in the direction of arrow  1004  when slider body  1000  is in operation. In another embodiment, air flows in the direction of arrow  1005  when slider body  1000  is in operation.  
     [0064]FIG. 13 b  is a cross-sectional view of slider body  1000 . FIG. 13 b  shows light channel  1010 , step  1008 , flange  1014 , and bevel  1012 .  
     [0065]FIG. 14 a  shows another embodiment of a slider body. Slider body  1100  includes positive pressure raised areas  1107   a  and  1107   b . In operation, air flows over slider body  1100  in either the direction of arrow  1104  or the direction of arrow  1103 . Light channel  1110  and step  1108  are shown in slider body  1100 . Slider body  1100  includes pressure relief grooves  1109   a  and  1109   b . Pressure relief grooves  1109 , in one embodiment, are 0.05 to 0.5 mm deep and trap loose surface contaminants on the surface of a rotating disc when slider body  1100  is operational. Other embodiments of slider bodies shown including those shown in FIGS. 8, 9 and  10  may also include similar pressure relief grooves parallel to the direction of air flow.  
     [0066]FIG. 14 b  is a cross-sectional view of slider body  1100 . FIG. 14 b  shows step  1108 , light channel  1110 , flange  1114 , and bevel  1112 .  
     [0067]FIG. 15 a  is an embodiment of a slider body  1500  that include a leading edge ramp  1513 . Leading edge ramp  1513  has a taper of approximately one degree and assists in forming an air bearing when air flows over the surface of slider body  1500  in the direction shown by arrow  1516 . FIG. 15 b  is a cross-sectional view of slider body  1500  showing flange  1514  that provides for alignment of slider body with a suspension.  
     [0068]FIG. 16 a  is an embodiment of a slider body  1600 . Slider body  100  includes grooves  1602  and  1604  perpendicular to the direction of air flow shown by arrow  1606 . In one embodiment, grooves  1602  and  1604  are 0.05 to 0.5 mm deep. The groove closest to the leading edge of slider body  1600  assists with damping the motion of slider body  1600 . FIG. 16 b  is a cross-sectional view of slider body  1600  showing flange  1614 .  
     [0069]FIG. 17 a  is an embodiment of a slider body  1700 . Slider body  1700  includes transverse groove that assists with damping the motion of slider body  1700 . Two air bearing pads  1704  and  1706  have different widths. This arrangement reduces flying roll. Flying roll occurs because the velocity of the air passing over the pad that is closer to the outer diameter of the MO disc is greater than that of the air passing over the pad that is closer to the inner diameter of the MO disc. Assuming that pad  1704  is closer to the outer diameter of the MO disc when air is traveling in the direction of arrow  1716 , the increased surface area of pad  1704  will compensate for the increased air velocity.  
     [0070]FIG. 17 b  is a cross-sectional view of slider body  1700  showing flange  1714 .  
     [0071]FIG. 18 a  is an embodiment of a slider body  1800  that includes leading edge ramp  1813 . The direction of air flow is shown by arrow  1816 . Slider body also includes air bearing pads  1804  and  1806 . Pad  1804  has greater surface area than pad  1804 . Recessed seat  1810  forms a laser light channel and also accommodates a magnetic head. Recessed seat  1810  provides for automatic alignment of a magnetic head with slider body  1800  at assembly. FIG. 18 b  is a cross-sectional view of slider body  1800  showing flange  1814 .  
     [0072]FIG. 19 a  is an embodiment of a slider body  1900  that includes air bearing pads  1904  and  1906 . Pad  1904  has greater surface are than pad  1906 . Pads  1904  and  1906  are not joined, but each include a leading edge ramp ( 1917  and  1919 , respectively). Slider body  1900  includes recessed seat  1921  for accommodating a magnetic head. The direction of air flow is shown by arrow  1916 . FIG. 19 b  is a cross-sectional view of slider body  1900  showing flange  1914 .  
     [0073]FIG. 20 a  is an embodiment of a slider body  2000 . Slider body  2000  includes air bearing pads  2004  and  2006  that include leading edge ramps  2017  and  2019 , respectively. Pad  2004  has greater surface are than pad  2006 . Slider body  2000  also includes recessed seat  2021  for accommodating a magnetic head. The direction of air flow is shown by arrow  2016 .  
     [0074]FIG. 20 b  is a cross-sectional view of slider body  2000  showing flange  2014  and seat  2001  for mating with a suspension.  
     [0075] Various slider body configurations such as those shown in the figures may be selected for a particular operation depending on the stability and stiffness required of the flying head in operation. Other concerns that contribute to the choice of a particular design relate to tribology in that certain designs may knock off or trap contaminants differently. In addition, a slider body design may be chosen based on the desired flying height of the magnetic head assembly. For example, a greater flying height usually requires greater surface area for the slider body. In drives in which miniaturization is a major concern, in other words in a drive in which there is very little clearance for a read/write head, a low flying height and, consequently, a small slider body may be appropriate.  
     [0076] Various combinations of features of the slider body embodiments shown may be made by one skilled in the art without departing from the scope of the invention.  
     [0077] According to one embodiment, the slider body is formed of plastic by injection molding. Injection molded plastic slider bodies are significantly less expensive in material and fabrication costs than prior art ceramic slider bodies. Because the present invention is usable in systems in which the flying height of the head is relatively great, the flatness requirement is not as stringent as low-flying designs. Because the present invention is usable in systems with dynamic loading and unloading, contact-start-stop events are not in the normal use pattern and therefore the slider body does not need to have superior wear characteristics. Another reason that injection molded plastic slider bodies are relatively inexpensive is that the coil may be bonded to the slider body as opposed to prior sputtering, glass bonding, or lapping of the magnetic core.