Abstract:
A piezo in-tongue microactuator includes a suspension assembly with a flexure tongue. The tongue has two slots that accept piezo actuators. The tongue also has multiple hinge flexible elements that translate the extension and/or contraction of the piezo actuators into rotary motion of the recording head. This rotary motion is then used to precisely position the recording element over the desired track on the hard disk drive and permits higher track density to be achieved.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates in general to hard disk drives and, in particular, to an improved system, method, and apparatus for a microactuator used in the precise positioning of the recording head element in a hard disk drive. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, a data access and storage system consists of one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. The hard disks themselves are usually made of aluminum alloy or a mixture of glass and ceramic, and are covered with a magnetic coating. Typically, one to six disks are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm). Hard disk drives have several different typical standard sizes or formats, including server, desktop, mobile and microdrive. 
         [0005]    A typical HDD also utilizes an actuator assembly. The actuator moves magnetic read/write beads to the desired location on the rotating disk so as to write information to or read data from that location having an air bearing surface (ABS) that enables the slider to fly at a constant height close to the disk during operation of the disk drive, by a cushion of air generated by the rotating disk. Within most HDDs, the magnetic read/write head transducer is mounted on a slider. A slider generally serves to mechanically support the head and any electrical connections between the head and the rest of the disk drive system. The slider is aerodynamically shaped to glide over the boundary layer of air dragged by the disk to maintain a uniform distance from the surface of the rotating disk, thereby preventing the head from undesirably contacting the disk. Each slider is attached to the free end of a suspension that in turn is cantilevered from the rigid arm of an actuator. Several semi-rigid arms may be combined to form a single movable unit having either a linear bearing or a rotary pivotal bearing system. 
         [0006]    The head and arm assembly is linearly or pivotally moved utilizing a magnet/coil structure that is often called a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting with its spindle, actuator VCM, and internal filtration system is then enclosed with a cover and seal assembly to ensure that no contaminants can enter and adversely affect the reliability of the slider flying over the disk. When current is fed to the motor, the VCM develops force or torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop and settle directly over the desired track. 
         [0007]    The motor used to rotate the disk is typically a brushless DC motor. The disk is mounted and clamped to a hub of the motor. The hub provides a disk mounting surface and a means to attach an additional part or parts to clamp the disk to the hub. In most typical motor configurations of HDDs, the rotating part of the motor or rotor is attached to or is an integral part of the hub. The rotor includes a ring-shaped magnet with alternating north/south poles arranged radially and a ferrous metal backing. The magnet interacts with the motor&#39;s stator by means of magnetic forces. Magnetic fields and resulting magnetic forces are induced by way of the electric current in the coiled wire of the motor stator. The ferrous metal backing of the rotor acts as a magnetic return path. For smooth and proper operation of the motor, the rotor magnet magnetic pole pattern should not be substantially altered after it is magnetically charged during the motor&#39;s manufacturing process. 
         [0008]    The suspension of a conventional disk drive typically includes a relatively stiff load beam with a mount plate at the base end, which subsequently attaches to the actuator arm, and whose free end mounts a flexure that carries the slider and its read/write head transducer. Disposed between the mount plate and the functional end of the load beam is a ‘hinge’ that is compliant in the vertical bending direction (normal to the disk surface). The hinge enables the load beam to suspend and load the slider and the read/write head toward the spinning disk surface. It is then the job of the flexure to provide gimbaled support for the slider so that the read/write head can pitch and roll in order to adjust its orientation for unavoidable disk surface axial run-out or flatness variations. 
         [0009]    The flexure in an integrated lead suspension is generally made out of a laminated multilayer material. Typically, it consists of a support layer (e.g., steel), a dielectric insulating layer (e.g., polyimide), a conductor layer (e.g., copper), and a cover layer (e.g., polyimide) that insulates the conductor layer. The electrical lead lines are etched into the conductor layer, while the polyimide layer serves as the insulator from the underlying steel support layer. The steel support layer is also patterned to provide strength and gimbaling characteristics to the flexure. The conducting leads, called traces, which electrically connect the head transducer to the read/write electronics, are often routed on both sides of the suspension, especially in the gimbal region. Normally the traces consist of copper conductor with polyimide dielectric insulating and cover layers but no support stainless steel layer and only provide the electrical function. The primary mechanical support function is provided by the flexure legs (e.g., steel) which normally run adjacent to the traces. 
         [0010]    Some hard disk drives employ micro- or milli-actuator designs to provide second stage actuation of the recording head to enable more accurate positioning of the head relative to the recording track. Milli-actuators are broadly classified as actuators that move the entire front end of the suspension: spring, load beam, flexure and slider. Micro-actuators are broadly classified as actuators that move only the slider, moving it relative to the load beam, or moving the read-write element only, moving it relative to the slider body. 
         [0011]    Previously, the objective for most designs was to provide a lateral motion of the slider recording element on the order of about 1 to 2 microns. The required lateral motion of the slider is defined by the track density of the drive and the size of the off-track motions of the slider required to follow the track due to turbulence, external vibration, etc. 
         [0012]    Milli-actuators have issues with dynamic performance. For example, when the entire load beam is actuated, milli-actuators exert significant reaction forces into the actuator arms, exciting relatively low frequency actuator resonances. They also have characteristically lower frequency resonances than microactuators. These two factors limit their performance. 
         [0013]    There are many types of micro-actuator designs. One type of microactuator (see, e.g., U.S. Pat. No. 7,159,300 to Yao) uses a ceramic U-shaped frame with thin-film piezo layers on the outer surfaces of the “U” to surround the slider, in the same plane as the slider, and attaches to the slider at the front of the U-shaped arms. Actuating the piezos on the two side arms moves the slider laterally. Although this design is workable, issues such as cost, reliability and fragility during shock have limited its usefulness. 
         [0014]    Another type of microactuator (see, e.g., U.S. Pat. No. 7.046,485 to Kuwajima) uses two thin-film piezos on either side of a thin adhesive layer. Two of these piezos are located below and in the same plane as the load beam. The piezos then alternately expand and contract to provide a rotary motion about a “hinge”, allowing rotary motion of the slider. 
         [0015]    In addition, various types of micro-electromechanical systems (“MEMS”) actuators have been designed. Some of these earlier designs used an electrostatic rotary design, but high cost and fragility made them unworkable. Thus, an improved system, method, and apparatus for a microactuator used in the precise positioning of the recording head element in a hard disk drive would be desirable. 
       SUMMARY OF THE INVENTION 
       [0016]    Embodiments of a system, method, and apparatus for a microactuator used in the precise manipulation of the slider head element in a hard disk drive are disclosed. A piezo actuator design overcomes the cost, manufacturability and fragility issues associated with previous microactuator designs. 
         [0017]    Rather than achieving a 1 to 2 micron motion of the slider, the invention provides movement of the slider element in the lateral (i.e., side-to-side) direction that is an order of magnitude less, or in the 0.1 to 0.2 micron range. This smaller positioning displacement works well because HDD track densities have increased and, combined with other disk drive design improvements, have reduced the off-track error that the slider is required to follow. One of the invention&#39;s design advantages is that only the cost of the piezos is added to manufacturing expenses. Another design advantage is that almost all other functions of the design are the same as for a conventional suspension, including the same gimbaling stiffnesses and manufacturing processes. 
         [0018]    In one embodiment, the hard disk drive suspension comprises a load beam extending in a longitudinal direction, which defines a lateral direction that is orthogonal to the longitudinal direction. A transverse direction is orthogonal to both the longitudinal and lateral directions. The load beam has a load beam dimple that defines a dimple axis extending in the transverse direction. A flexure is mounted to the load beam and has a tongue with a leading edge portion and a slider attachment platform that is longitudinally spaced apart from the leading edge portion. 
         [0019]    A slider is mounted to the slider attachment platform and has a freedom of rotation about the dimple axis. Electrical conductors extend along the flexure and are in electrical communication with the slider. The conductors have conductor outrigger portions that are outboard of the tongue in the lateral direction. A microactuator is mounted directly in the tongue between the leading edge portion and the slider attachment platform. The microactuator selectively rotates the slider about the dimple axis. 
         [0020]    The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    So that the manner in which the features and advantages of the present invention are attained and can be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings. However, the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments. 
           [0022]      FIG. 1  is a schematic plan view of one embodiment of a disk drive constructed in accordance with the invention; 
           [0023]      FIG. 2  is a top isometric view of one embodiment of a load beam and suspension for the disk drive of  FIG. 1  and is constructed in accordance with the invention; 
           [0024]      FIGS. 3A and 3B  are side and enlarged side views, respectively, of one embodiment of the load beam and suspension and is constructed in accordance with the invention; 
           [0025]      FIG. 4  is an enlarged isometric view of a distal end of one embodiment of the suspension shown without the load beam and is constructed in accordance with the invention; 
           [0026]      FIG. 5  is a further enlarged half-isometric view of one embodiment of the suspension shown with the load beam and is constructed in accordance with the invention; 
           [0027]      FIG. 6  is a bottom isometric view of one embodiment of the suspension and is constructed in accordance with the invention; 
           [0028]      FIG. 7  is an enlarged lower isometric view of one embodiment of the suspension shown without a slider and is constructed in accordance with the invention; 
           [0029]      FIG. 8  is a plan view of one embodiment of the suspension illustrating a range of motion thereof and is constructed in accordance with the invention; 
           [0030]      FIG. 9  is an enlarged, partially sectioned side view of one embodiment of a piezo portion of the suspension and is constructed in accordance with the invention; 
           [0031]      FIG. 10  is a simplified top view of one embodiment of the suspension constructed in accordance with the invention. 
           [0032]      FIG. 11  is a partial sectional view of one embodiment of a leading edge connection for the piezo and is constructed in accordance with the invention; 
           [0033]      FIG. 12  is a partial sectional view of one embodiment of some of the electrical connections for the suspension and is constructed in accordance with the invention; 
           [0034]      FIG. 13  is a partial plan view of one embodiment of a stainless steel layer for the flexure and is constructed in accordance with the invention; 
           [0035]      FIG. 14  is a partial plan view of one embodiment of an insulator layer for the flexure and is constructed in accordance with the invention; and 
           [0036]      FIG. 15  is a partial plan view of one embodiment of a conductor layer for the flexure and is constructed in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    Referring to  FIG. 1 , a schematic drawing of one embodiment of an information storage system comprising a magnetic hard disk file or drive  111  for a computer system is shown. Drive  111  has an outer housing or base  113  containing at least one magnetic disk  115 . Disk  115  is rotated by a spindle motor assembly having a central drive hub  117 . An actuator  121  comprises one or more parallel actuator arms  125  in the form of a comb that is pivotally mounted to base  113  about a pivot assembly  123 . A controller  119  is also mounted to base  113  for selectively moving the comb of arms  125  relative to disk  115 . 
         [0038]    In the embodiment shown, each arm  125  has extending from it at least one cantilevered load beam  127 . A magnetic read/write transducer or head is mounted on a slider  129  and secured to a flexure that is flexibly mounted to the load beam  127 . The read/write heads magnetically read data from and/or magnetically write data to disk  115 . The slider  129  is usually bonded to the flexure tongue  208  ( FIG. 4 ). The head is typically formed from ceramic or intermetallic materials and is pre-loaded against the surface of disk  115  by the suspension. 
         [0039]    Suspensions have a spring-like quality which biases or urges the air bearing surface of the slider  129  against the disk  115  to enable the creation of the air bearing film between the slider  129  and disk surface. A voice coil  133  housed within a voice coil motor magnet assembly  134  is also mounted to arms  125  opposite the head gimbal assemblies. Movement of the actuator  121  (indicated by arrow  135 ) by controller  119  moves the head gimbal assemblies radially across tracks on the disk  115  until the heads settle on their respective target tracks. 
         [0040]    Referring now to  FIGS. 2-15 , various illustrations of embodiments of suspensions for a hard disk drive are shown. In one version, the invention comprises a load beam  201  ( FIG. 2 ) extending in a longitudinal direction x and having a longitudinal axis  202 . A lateral direction y is defined as being orthogonal to the longitudinal direction x. A transverse direction z is orthogonal to both the longitudinal and lateral directions x, y. The load beam  201  has a load beam dimple  203  ( FIG. 5 ) that defines a dimple axis  205  extending in the transverse direction z. The load beam dimple  203  may be provided with a transverse dimension on the order of 7.5 microns below the load beam bottom surface to provide additional transverse clearance for the piezos with respect to the load beam when the flexure tongue, piezos and slider are rotated in the pitch direction (i.e., about a lateral axis) by approximately 1.5 degrees prior to loading onto the disk. 
         [0041]    As shown in  FIGS. 4 and 5 , a flexure  207  is mounted to the load beam  201  and has a tongue  208  with a leading edge portion  209 , a trailing edge limiter  211 , and a slider attachment platform  213  that is longitudinally spaced apart from the leading edge portion  209 . In one embodiment, the tongue  208  may be defined as extending from the tongue leading edge portion  209  to the trailing edge limiter  211 . 
         [0042]    The flexure  207  also may comprise a pair of tabs  210  that extend in lateral directions y and are connected to the conductor outrigger portions  223  as shown. An insulator is located between the tabs  210  and the copper traces in the conductor outrigger portions  223 . In one embodiment, the conductor outrigger portions define a maximum dimension of the flexure in the lateral direction, and the pair of tabs is connected to the conductor outrigger portions at or adjacent to the maximum dimension of the flexure. 
         [0043]    In one embodiment, a slider  129  ( FIGS. 5 and 6 ) is bonded to the stainless steel lower surface of the slider attachment platform  213  and has a freedom of rotation about the dimple axis  205 . A plurality of traces or electrical conductors  221  ( FIGS. 6 and 7 ) extend along the load beam  201  and are in electrical communication with the slider  129 . The traces  221  have trace outrigger portions  223  that are outboard of the flexure  207  in the lateral direction y. 
         [0044]    As best shown in  FIGS. 4 and 8 , the invention also comprises a microactuator  231  that is located directly in the tongue  208  of the flexure  207 . In one embodiment, the microactuator  231  extends between the leading edge portion  209  and the slider attachment platform  213 . The microactuator  231  selectively rotates the slider  129  (compare, e.g.,  FIGS. 6 and 7 ) about the dimple axis  205 . In the hard disk drive, the trailing edge  222  of the slider  129  has transducers for reading data from and/or writing to the magnetic disk  115  ( FIG. 1 ). In the embodiment of  FIG. 8 , which depicts a deformed shape plot that is exaggerated to show deflection, the microactuator  231  rotates the slider  129  by ±0.02 degrees about the dimple axis  205 , which laterally translates the transducers by ±0.16 microns (i.e., distance  234 ) relative to the longitudinal axis  202 . 
         [0045]    Referring now to  FIGS. 5 and 7 , a polyimide dimple  233  may be transversely located between the flexure  207  and the slider  129  at the dimple axis  205 . One or more rigid structural adhesive pads  235  also may be located between the slider  129  and the slider attachment platform  213 . In addition to adhesive pads  235 , additional registration pads  236  may be mounted transversely between the traces  237  and the slider  129 . Moreover, a center registration pad  238  may be located laterally between the outer registration pads  236  and mounted longitudinally adjacent the polyimide dimple  233 . As shown in  FIGS. 7 ,  12  and  15 , a small conductive via  266  may be used to electrically connect pad  238  to the steel layer (e.g., slider attachment platform  213 ) of the flexure. 
         [0046]    In one embodiment, the microactuator  231  comprises a piezo actuating device that is responsive to electrical signals provided thereto by additional traces  237  ( FIG. 7 ). The piezo microactuator may comprise a pair of piezos  239  ( FIG. 4 ) extending substantially longitudinally. As best shown in  FIGS. 4 and 8 , each piezo  239  may be oriented with respect to the longitudinal axis at an angle (e.g., less than 5 degrees), such that the piezos are longitudinally symmetrical about the longitudinal axis. However, the angle may be more or less than 5 degrees. 
         [0047]    Piezoelectric ceramics are known for what are called the piezoelectric and reverse piezoelectric effects. The piezoelectric effect causes a crystal to produce an electrical potential when it is subjected to mechanical stress. In contrast, the reverse piezoelectric effect causes the crystal to displace when it is placed in an electric field with a particular orientation relative to the previously poled direction of the piezo. 
         [0048]    In the embodiment shown in  FIGS. 6 and 7 , the slider  129  is provided with signals through six traces  221 , and the piezos  239  are provided with signals through two traces  237  that are laterally spaced outboard from the six traces  221 . As best shown in  FIGS. 6 ,  7  and  15 , the trace outrigger portions  223  laterally converge at the trailing edge limiter  211 , longitudinally extend toward the slider  129  to define a trace neck width  261 , and then diverge laterally from the trace neck width  261  to the slider  129  to define a trace slider width  263  that is greater than the trace neck width  261 . 
         [0049]    Referring to  FIGS. 8 and 9 , the trailing end  242  of each piezo  239  is connected to the slider attachment platform  213  through a piezo hinge  241 . The leading ends  244  of the piezos  239  are mounted to the leading edge portion  209  of the tongue  208 . The leading ends  244  of the piezos  239  may be grounded directly to a steel layer (e.g., at leading edge portion  209  in  FIG. 11 ) of the flexure through a small conductive via  212  ( FIGS. 11 and 15 ). 
         [0050]    As shown in  FIG. 9 , the piezos  239  may be connected to the leading edge portion  209  and to the piezo hinges  241  with solder and/or conductive adhesive at one or more locations  251 ,  252  (e.g., longitudinally, laterally or transversely). Structural adhesive  253  also may be used for sealing or additional strength. The steel layer of the flexure has lower surfaces  411 ,  413  extending substantially in an x-y plane. The piezos  239  have lower surfaces  415  extending substantially in the x-y plane such that they are co-planar with surfaces  411 ,  413 . 
         [0051]    As shown in  FIGS. 4 and 8 , a flexure hinge  243  is formed in the tongue  208  laterally between the pair of piezos  239  and the piezo hinges  241 . The flexure hinge  243  is intersected by the dimple axis  205 . A center link  240  extends from the leading edge portion  209  to the flexure hinge  243 . Thus, in one embodiment, the microactuator  231  may be defined as piezos  239 , piezo hinges  241 , flexure hinge  243  and center link  240 . Alternatively, piezo hinges may be provided at both ends of the piezos (not shown), rather than only on their trailing ends. 
         [0052]    In the embodiment shown, each piezo  239  comprises a rectangular block having dimensions on the order of 1 mm in length, 0.220 mm in width, and about 40 to 60 microns in thickness. The tongue  208  has a steel layer with a thickness on the order of 20 microns. As best shown in  FIGS. 4 and 8 , the piezos  239  have a longitudinal length that is less than an overall length of the tongue  208 . The piezos  239  have lower x-y surfaces that abut a polyimide layer  245  ( FIGS. 6 and 14 ), having a transverse thickness of about 15 microns, that is substantially parallel to the x-y surfaces of the piezos. The polyimide layer  245  attenuates resonances and prevents significant movement of the piezos during shock. The polyimide layer  245  has a lateral dimension that is greater than a combined lateral dimension of the piezos  239 . In addition, the polyimide layer  245  is secured to multiple steel portions of the tongue  208 , and the polyimide layer  245  is free of contact with the slider  129 . 
         [0053]    As illustrated in  FIG. 9 , each piezo  239  is provided with a minimum transverse clearance  322  (in the z-direction) on the order of  30  microns relative to the load beam  201  when the disk drive is not in operation, or prior to loading the slider on the disk. As shown in  FIG. 3 , the slider  129  has a nominal pitch rotational range  324  (i.e., about a lateral axis) of approximately 1.5 degrees to accommodate the load/unload process in the disk drive. The piezos  239 , which may comprise thick-film or thin-film piezos, may be actuated by voltage applied to conductive layers inside the piezos  239 . Each piezo  239  may comprise multiple piezoelectric material layers (e.g.,  FIG. 9  depicts three layers) with a voltage of 10 to 20 volts being applied across each layer. Opposite polarity voltage is applied to the two different piezos  239 , such that one piezo expands and the other piezo contracts to rotate the slider  129 . In one version, if the voltage is biased (e.g., +10±10V, or +20±20V), depoling of the piezos  239  may be eliminated. 
         [0054]    As best shown in  FIGS. 8 and 13 , the flexure may comprise steel outriggers  401  that are located laterally between the tongue  208  and piezos  239 , and the trace outrigger portions  223 . The steel outriggers  401  extend longitudinally beyond the trailing ends  242  of the piezos  239  and, in the embodiment shown, beyond the piezo hinges  241  and flexure hinge  243 . Returns  403  are formed at the distal ends of the steel outriggers  401 . The steel outriggers reverse direction in the longitudinal direction from the returns  403  thereof and have extensions  405  that connect to the leading edge portion  209  where they are attached to the leading ends  244  of the piezos  239 . 
         [0055]    As described herein, the trailing edge limiter  211  ( FIGS. 4-6 ) is located at the trailing end of the tongue  208 . Some embodiments of the invention also utilize a leading edge limiter  301 . The leading edge limiter  301  is located longitudinally adjacent the leading edge portion  209  of the tongue  208  and protrudes upward and rearward therefrom. The leading edge limiter  301  and trailing edge limiter  211  serve to constrain slider/flexure transverse motion relative to the load beam  201  during shock 
         [0056]    Referring now to  FIGS. 5 and 10 , the leading edge limiter  301  extends through a window  321  formed in the load beam  201  extending in an x-y plane. The window  321  has a trailing edge  323  extending in the lateral direction that is located above and adjacent to a longitudinal midsection  325  ( FIG. 10 ) of the piezos  239 . The window  321  has a leading edge  327  that is longitudinally spaced apart from its trailing edge  323  to provide transverse clearance for leading edges  244  of the piezos  239  relative to the load beam  201 . The window  321  also has a lateral dimension  329  that exceeds a combined lateral dimension  331  of the piezos  239 . 
         [0057]    In the embodiment shown, the window  321  is provided with tabs  333  ( FIG. 10 ) that extend longitudinally a short distance from the trailing edge  323  toward leading edge  327 . Centerlines of the tabs  333  are transversely located substantially above the centerlines of the piezos  239 . In addition, the tabs  333  have narrower lateral dimensions than the piezos  239 , such that any transverse deflection of the piezos would cause the piezos to be contacted by the tabs  333  away from the lateral side edges of the piezos. 
         [0058]    The invention has numerous features that further improve its performance. For example, the polyimide (PI) and cover layer that bridge the piezo slots in the stainless, have several functions, including eliminating several resonances, and serving as a platform to prevent large piezo displacements during shock. 
         [0059]    There are two dimples in one embodiment of the design. The load beam dimple is standard on all suspensions. However, the polyimide dimple bridges the gap between the bottom of the flexure tongue stainless steel and the slider. The polyimide dimple allows a direct transmission of the dimple force from the load beam dimple to the slider. The flexure/trace connection(s) are standard features and help to reduce turbulence off track caused by trace vibrations. The hinge is the center of rotation for the slider. The piezo hinges allow the two different piezos to simultaneously extend and contract in a linear manner, while allowing the slider attachment platform and slider to rotate. 
         [0060]    The assembly process for the design shown may comprise inserting the two piezo actuators into two slots in the flexure tongue. The piezos may be electrically attached to the flexure using two or three solder balls on each end. Alternatively, a solder-reflow process may be used between selected portions of each end of the piezos. Additional bonding may be used on the piezo ends and the adjacent stainless steel of the flexure to provide additional structural integrity or sealing to prevent contamination. After attaching the piezos to the flexure tongue, the flexure may be attached to the suspension load beam as in a normal suspension assembly process. The slider assembly process is the same as for a conventional femto slider/suspension assembly. 
         [0061]    The invention has numerous advantages over prior art designs. The invention is simple in that it only adds two additional elements in the piezo actuators. With regard to packaging, the design only adds an additional 20 to 30 microns of height to the standard femto slider/suspension requirements. The additional height is required to offset the top of the slider from the flexure bottom to allow unimpeded rotation to occur. 
         [0062]    The invention maintains a low mass despite adding new components. The additional mass added by the piezos is almost completely balanced by the stainless slots removed from the flexure tongue. This design results in low mass and similar in z-direction shock performance as a conventional femto slider/suspension assembly. 
         [0063]    This new design also provides low pitch and roll stiffnesses. The pitch and roll stiffnesses of the suspension are the same as for a standard suspension, resulting in no impact on flying ability of the air bearing system. 
         [0064]    The invention may be provided with a high resonant frequency. While the primary motion of the slider is rotary, there is a small, lateral, unbalanced force with the design that excites the sway mode of the suspension. With the proper suspension design, the suspension sway mode and, hence, the first mode excited by the microactuator is in the range of 25 kHz. This is well above the 20 kHz requirement of a two-stage actuator second stage. Moreover, the rotary mode of the actuator is extremely high in frequency (e.g., on the order of &gt;30 kHz). The performance will vary depending on the specific requirements of each application. The high frequency of the rotary mode essentially eliminates this mode from being a consideration for the second stage servo design. 
         [0065]    Because the load beam, flexure and slider system are essentially unchanged from a conventional femto slider and suspension system, air turbulence excitation of the system and the resulting off-track performance is similar to existing devices. Furthermore, since there are no significant changes to the current slider suspension assembly process, no additional capital expenditures are required to accommodate the design. 
         [0066]    While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.