Tape head system with controllable electrostatic elements

A tape head system includes a read and/or write head having at least one read and/or write element configured to read from and/or write to magnetic tape and at least one electrostatic element arranged adjacent to the read and/or write element; and a controller configured to apply a potential to the at least one electrostatic element.

PRIORITY

This application claims priority to Great Britain Patent Application No. 1211469.0, filed Jun. 28, 2012, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference.

BACKGROUND

The invention relates to a tape head system and to a method for operating a tape head system.

In modern tape systems, data is organized in data tracks which are written and read back in a parallel fashion by a read and write head comprising servo read, data read and data write elements, i.e., transducer elements. These data tracks run in the longitudinal direction of the magnetic tape and are much narrower than the excursions the magnetic tape experiences in the lateral direction as a result of imperfections in the mechanical entrainment system. Therefore, it is crucial to accurately position the head relative to the magnetic tape in the lateral direction, and to maintain this relative position as the magnetic tape is streamed. To this end, as well as for other purposes, media manufacturers write servo tracks on the magnetic tape parallel to and interleaved with the data tracks. The servo read elements read the servo information stored in the servo tracks, which is then used for aligning the head with the data tracks on the magnetic tape.

Servo tracks are typically written to the magnetic tape using one servo write element for each servo track. Each servo write element generally comprises a yoke having one or more gaps and a coil for producing a magnetic field at each gap. The write elements are configured to imprint a specific pattern on the magnetic tape via fringing magnetic fields. This pattern contains the information required to determine the instantaneous lateral location of the data read and write elements (or the head as a whole) using a timing-based-servo (TBS) scheme as for example described in EP 0 690 442 A2.

TBS is a technology that was developed specifically for linear tape drives. It has been adopted by the Linear Tape Open (LTO) Consortium as a standard for the so-called LTO tape drive systems. In TBS systems, servo patterns generally comprise chevron shapes, having magnetic transitions with two different azimuthal slopes. An estimate of the head position is derived from the relative timing of pulses (also known as di-bits) generated by the read element reading the servo pattern.

Generally speaking, the magnetic tape should be in close contact with the servo write element to ensure a high-quality servo pattern being imprinted during writing. When the magnetic tape is run across the servo write head, an air bearing layer forms (air being trapped between the magnetic tape and the servo write head). Current servo write heads use one or more sharp edges to skive off the air. A small low pressure pocket forms behind the skiving edge, and atmospheric pressure then pushes the magnetic tape into contact with the servo write head.

SUMMARY

In one embodiment, a tape head system includes a read and/or write head having at least one read and/or write element configured to read from and/or write to magnetic tape and at least one electrostatic element arranged adjacent to the read and/or write element; and a controller configured to apply a potential to the at least one electrostatic element.

DETAILED DESCRIPTION

According to a first aspect, a tape head system is provided. The tape head system comprises a read and/or write head having at least one read and/or write element for reading from and/or writing to magnetic tape and at least one electrostatic element arranged adjacent to the read and/or write element. Further, the tape head system comprises a controller for applying a potential to the at least one electrostatic element.

One general idea is that by applying a defined potential to the at least one electrostatic element, the electrostatic element can be controlled so as to exert an electrostatic force on the magnetic tape. In doing this, a distance between the read and/or write head or the read and/or write element and the magnetic tape may be controlled. For example, the distance may thus be controlled to be equal to zero (when the magnetic tape contacts the read and/or write head) or in the region between 0 and 20 μm, specifically 0 and 10 μm, and more specifically 0 and 1 μm (herein referred to as “close relationship”). The force pulling the magnetic tape towards the read and/or write head or the read and/or write element may also be controlled. The force may be controlled to be in the range of 0 to 10 N, for example. The force is dependent on the applied voltage and the surface area spanned by the electrostatic elements; a higher voltage results in more force, and a smaller surface area results in a smaller force. The controller may be configured as an open or closed-loop feedback controller to control the distance.

Typically, magnetic tape comprises a number of thin conductive and dielectric layers. Thus, when the magnetic tape is brought close to the at least one electrostatic element, image charges appear on the magnetic tape, i.e., there is a charge separation within the tape due to the external electric field generated by the at least one electrostatic element, when the potential is applied by the controller. As a result, the magnetic tape is attracted to the at least one electrostatic element. Furthermore, by statically or dynamically controlling the potential applied to the at least one electrostatic element by the controller, the electrostatic force exerted on the magnetic tape may be controlled to achieve the desired spacing or force mentioned above.

The write head may be formed as a servo write head. At least one write element of the write head may comprise a yoke having at least one, optionally at least two gaps, and a coil for producing a magnetic field at the gap. Typically, the coil comprises a plurality of windings. A “gap” presently refers to an interruption in the yoke defined between opposite magnetic poles. The yoke comprises a magnetic material, for example iron, and is magnetized when a current flows through the coil. The yoke may be ring-shaped.

The head, in particular the read and/or write element(s), may be assembled from separately fabricated parts, or built-up from a planar substrate using thin-film microfabrication techniques. The latter presents advantages in terms of fabrication and decreased inductance and current, which enable writing more abrupt servo patterns and/or formatting the magnetic media at a greater speed. For example, the head and/or the read and/or write element may be built on a wafer, for example a silicon or AlTiC (Aluminium-Titanium-Carbide) wafer.

The head, in particular the servo write head, may be a planar head comprising a planar (also referred to as pancake) coil. Alternatively, the head, in particular the servo write head, may be comprise with a helical coil. A combination of planar or helical coils is also possible.

Generally speaking, the at least one read and/or write element may be configured for writing and/or reading data or servo tracks.

According to an embodiment, the controller is configured to ground the at least one electrode. When the magnetic tape moves over the read and/or write head during reading or writing, this results in friction causing triboelectric charging of the head surface. This charging creates an attractive electrostatic force increasing the pressure at which the magnetic tape is pushed against the head. This in turn increases friction and wearing of the head. The increased friction leads to increased velocity variations of the magnetic tape. When a servo pattern is written, these velocity variations lead to an imprinted noise on the TBS position measurement. By now grounding the at least one electrode, the triboelectric charge is removed. Thus, the attractive electric forces between the magnetic tape and the head surface are brought down to substantially zero. Thus, friction is reduced, and the velocity variations as mentioned above are substantially avoided resulting in an accurate TBS position measurement. The electrostatic element may be formed as a metal island integrated into the head surface. The metal island may be configured such that it also reduces wear on the head besides its grounding effect. Multiple of these metal islands may be provided on the head surface. In particular, these metal islands may be provided on a servo write head surface.

According to a further embodiment, the controller is configured to apply a potential to the at least one electrode so as to compensate for a work function. Due to the different materials used for the magnetic tape and the head surface, a small potential results, when these materials are brought into a close relationship or in contact with each other. The work function is defined as the minimum energy (usually measured in electron volts) needed to remove an electron from the (solid) material to a point immediately outside the (solid) material surface. In this context, “immediately” means that the final electron position is far from the surface on the atomic scale, but still close to the solid on the microscopic scale. When the potential applied to the at least one electrode corresponds to the work function, attractive forces between the magnetic tape and the head surface may be reduced even more compared to the embodiment where the at least one element is grounded. Thus, substantially no electrostatic force acts on the magnetic tape during reading and/or writing.

According to a further embodiment, the controller is configured to apply a potential to the at least one electrode so as to maintain a controlled spacing between the magnetic tape and the head, the controller being configured as a closed-loop feedback controller so as to maintain the controlled spacing between the magnetic tape and the head. The controlled spacing (or air bearing) may be formed such that the magnetic tape is always kept at a distance from the surface of the head. Thus, the magnetic tape does not contact the surface of the head at any point. Alternatively, the magnetic tape may contact the surface of the head at one or more sections. At the same time, one or more air bearings are present between the magnetic tape and the head surface in one or more other sections of the head.

According to a further embodiment, the controller is configured to apply a potential to the at least one electrode so that the magnetic tape contacts the head along a first section of the head comprising the read and/or write element or is arranged in close relationship thereto and is spaced apart from the head along a second section of the head adjacent to the first section of the head by an air bearing. Thus, the area of the magnetic tape that is in contact with the head can be significantly reduced. Only the areas of the magnetic tape, which are read from or written to, are in contact with the head or the read and/or write element. Thus, friction between the magnetic tape and the head is controlled allowing for, e.g., improved accuracy when writing a servo pattern. Also, by controlling the potential at the at least one electrostatic element accordingly, the attractive force between the magnetic tape and the head can be controlled so as to reduce friction even further.

According to one embodiment, the at least one electrode is provided with a non-conductive layer on the side facing the magnetic tape. In particular, where electrically conducting tape is used, this will prevent shorting between multiple electrostatic elements. Or, a non-conducting tape is used. “Conducting” or “non-conducting” may refer to only one side of the tape, i.e., the side of the tape in contact or in close relationship with the head surface or the read and/or write element.

According to a further embodiment, at least two electrostatic elements are arranged before and after the read and/or write element in a direction of travel of the magnetic tape. Thereby, the magnetic tape may be accurately positioned with respect to the read and/or write element.

According to a further embodiment, the first section of the head in contact or in close relationship with the magnetic tape spans only from the one electrostatic element to the other electrostatic element with the read and/or write element arranged in between. Thus, the magnetic tape is only in contact with a section of the head. The magnetic tape may only be partially in contact or in close relationship with each electrostatic element.

According to a further embodiment, at least a first and a second electrostatic element are arranged before and at least a third and fourth electrostatic element are arranged after the at least one read and/or write element. By having multiple electrostatic elements arranged before and after the read and/or write element, electrostatic attractive forces between the magnetic tape and the head may be better controlled.

According to a further embodiment, the controller may be configured to apply the same or opposite potentials to the electrostatic elements. “Same” means same magnitude and polarity, and “opposite” means same magnitude, but opposite polarity. A bi-polar arrangement, that is using electrostatic elements having opposite potentials, may be preferable, since charges on the head surface and in the magnetic tape may be controlled more easily.

According to a further embodiment, the controller is configured to apply opposite potentials to the first and second electrostatic elements as well as to the third and fourth electrostatic elements. Thus, the charges on the first and second electrostatic element are equal and opposite, such that the magnetic tape has no net charge and is substantially at ground potential. Similarly, the charges on the third and fourth electrostatic element are equal and opposite such that the magnetic tape has no net charge and is at virtual ground potential. Thereby, an electrostatically balanced arrangement is obtained (bi-polar configuration).

According to a further embodiment, the first and second and/or third and fourth electrostatic element are arranged, having regard to a direction of travel of the tape, behind or next to each other. “Next” means in the transversal direction of the tape.

According to a further embodiment, the at least one electrostatic element and the at least one read and/or write element form a cluster, wherein multiple clusters are arranged on the head. For example, the distance between respective electrostatic elements and read and/or write elements of each cluster are smaller than the distances between the clusters.

According to a further embodiment, the controller is configured to control the at least one electrostatic element of each cluster so that the magnetic tape only contacts or is arranged in close relationship with the head along first sections of the head and is spaced apart from the head at second sections of the head in between the first sections by an air bearing respectively.

The head is configured with a bevel at at least one of the second sections. The bevel may be formed concave, i.e., the bevel curves into the material of the head. Thereby, it is ensured that the magnetic tape only touches the head at the first sections, thus keeping friction at a minimum.

According to a further embodiment, the tape head system comprises a tensioning unit for tensioning the magnetic tape, wherein the controller is configured to apply a potential to the at least one electrostatic element so as to pull the magnetic tape towards the read and/or write head for reading and/or writing. The controller may be configured to apply a potential to the at least one electrode so as to pull the magnetic tape towards the head for reading and/or writing even when the magnetic tape is spaced from the head by a distance between 0.1 and 100 μm. Stiction between the magnetic tape and the head surface is a result of the trend to use increasingly smooth materials. The use of smooth materials can, particularly at low or zero velocity of the magnetic tape, cause the magnetic tape to stick to the head due to stiction effects. When removing the magnetic tape from the head, this may cause damage to the magnetic tape. According to the embodiment, simply by controlling the potential applied at the at least one electrostatic element, the magnetic tape may be removed from the head in a controlled fashion. For example, by reducing the electrostatic attractive forces between the magnetic tape and the at least one electrostatic element, the magnetic tape is removed from the head due to the tension in the magnetic tape produced by the tensioning unit.

Further, a method for operating a tape head system, in particular a tape head system in accordance with the present invention, is provided. A potential is applied to at least one electrostatic element of a read and/or write head of the tape head system arranged adjacent to at least one read and/or write element of the read and/or write head by a controller of the tape head system.

Features and advantages explained above in the context of the tape head system apply mutatis mutandis to the method of the present invention.

In the following, exemplary embodiments of the present invention are described with reference to the enclosed figures.

FIG. 1shows a tape head system100according to one embodiment. The tape head system100comprises a read and/or write head102having one read and/or write element104. Also, the head102has two electrostatic elements106,108arranged adjacent to and, having regard to a direction of travel110of a magnetic tape112, before and after the read and/or write element104. The read and/or write element104and the electrostatic elements106,108may be arranged on a substrate114of the head102. The substrate114may be formed as a wafer, for example a silicon or AlTiC wafer. The elements104,106,108are electrically isolated from each other. The electrostatic elements106,108may comprise titanium-nitride (TiN), iron-nitride and an additional element X (FeXN where X=Ti, Al, Hf, CoHf or CrHf), nickel-iron (NiFe), doped diamond like carbon (DLC), tungsten or, generally, any suitable metal.

The tape112, which is also part of the tape head system100, is fed past the front surface126of the head102having the elements104,106,108integrated therein.

Further, the tape head system100comprises a controller116for applying a potential V1, V2to the electrostatic elements106,108. The controller116may comprise a first voltage source118applying a voltage V1to the electrostatic element106. Further, the controller116may comprise a voltage source120for applying a voltage V2to the electrostatic element108. The voltage sources118,120may be configured as controllable voltage sources. For example, a unit122may be provided, which controls the voltages V1, V2applied to the electrostatic elements106,108. Thus, the voltages V1, V2may vary as a function of time t. The unit122may receive an input signal124from a main controller (not shown) of the tape head system100.

The tape head system100may also comprise tensioning units128. The tensioning units128may be arranged on either side of the tape head102and apply a tension to the magnetic tape112. As a result, when no electric potential is applied to the electrostatic elements106,108, the tape112is spaced apart from the surface126over the length l of the head102as indicated by the dotted lines inFIG. 1. The distance d1from the surface126to the magnetic tape112may be large, for example between 1 and 100 μm.

When data is to be read from or written to the tape112, or a servo pattern is to be written to or read from the tape112, a voltage V1, V2is supplied to the electrostatic elements106,108by the controller116, when the input signal124indicates to the controller116that a read and/or write operation is to be performed. As a result of electrostatic forces between the electrostatic elements106,108and the tape112, a section130of the tape112is pulled in close relationship to the surface126of the head102. The distance d2between the read and/or write element104and the tape112at the section130may be in the range of 10 to 200 nm or less. Also, the distances d3and d4between a respective electrostatic element106,108and the tape112at the section130may lie, for at least a part of a respective electrostatic element106,108between the distances d1and d2. The sections138of the tape112may remain at the distance d1.

As the tape112is moved past the head102using one or more electric motors (not shown), the read and/or write element104writes to or reads from the tape112. Once the read and/or write process is completed, a corresponding signal124is provided to the controller116and thus no potentials are applied to the electrostatic elements106,108. Then, the section130returns to its original position indicated by dotted lines inFIG. 1due to the tension in the tape112.

As can be seen fromFIG. 1, an air bearing132is present between the head102and the tape112even during reading and/or writing. The air bearing132may be present over the entire length l of the head102. In an alternative embodiment (seeFIG. 4), no air bearing may be present at the section130. In the latter case, the section130of the tape112is in direct contact with the read and/or write element104and the electrostatic elements106,108(or at least with portions of the elements106,108). According to a further alternative embodiment, only the read and/or write element104is in direct contact with the section130of the tape112.

The tensioning unit128is an optional feature and reading and/or writing may still be performed as illustrated by the embodiment ofFIG. 1. The tensioning unit128is, however, advantageous in removing the tape112from the head102. Tension may also be provided and controlled by controlling the torque applied by the electric motors used to move the tape112past the head102.

It is to be noted that the head102does not have a skiving edge to produce a reduced pressure region between the tape112and the surface126of the head102in order to ensure contact between the tape112and the read and/or write element104. However, such a skiving edge may be present. The head102may be formed with rounded edges136as illustrated in dotted lines inFIG. 1at opposing ends in the direction of travel110of the tape112.

By maintaining the air bearing132, triboelectric charging of tape112is prevented, thus reducing or preventing friction between the tape112and the head102. This again reduces velocity variations of the tape112in the direction of travel110, which improves reading and/or writing quality.

Also, the controller116can control the potentials V1, V2continuously, i.e., as a function of time, in order to keep the distance d2at an ideal level. Also, the controller116may control the distance d2as a function of the distance d2. In other words, the distance d2is provided as the input signal124to the unit122. For example, a sensor134measuring the distance d2may be integrated into the head102, for example into the read and/or write element104. The sensor134then produces the input signal124. Thus, a closed loop control system is provided, which allows accurate control of the distance d2.

With reference toFIG. 2, a method for operating the tape head system100ofFIG. 1is illustrated according to one embodiment.

In a first operation, S1, the tape112is started to run forward or backward.

In operation S2, the electrostatic elements106,108are energized and thus pull the tape112close to the head102.

In operation S3, writing and/or reading (reading is presently also to encompass “seeking”) operations. For example, the read and/or write element104writes data to the tape112. The read and/or write element104could just as well write a servo pattern to the tape112.

In operation S4, the electrostatic elements106,108are de-energized, i.e., no voltage V1, V2is applied, to release the tape112from the head102.

In operation S5, the tape112is stopped. The operations S1to S5may be repeated as needed.

FIG. 3illustrates a method for operating a tape head system100according to a further embodiment.

In a first operation, T1, the tape112is started to run forward or backward, corresponding to operation S1mentioned above.

Then, the distance D1is measured for example by the sensor134(step T2).

In operation T3, the controller116adjusts the voltages V1, V2to achieve the desired distance d2.

In another operation (not specifically shown inFIG. 3since this operation corresponds to operation S3mentioned above), writing and reading operations are performed.

In operation T4, it is decided whether to stop running the tape112. If no, operations T2, T3and the writing and reading operations are repeated. If yes, the electrostatic elements106,108are de-energized in a operation T5to release the tape112from the head102.

In operation T6, which corresponds to operation S5mentioned above, the tape112is stopped.

If desired, the operations T1to T6and the writing and reading operations may be repeated as often as required.

FIG. 4partially illustrates a tape head system100according to a further embodiment. The tape head system100ofFIG. 4differs from the one ofFIG. 1in that insulating layers400are provided on top of each electrostatic element106,108. In particular in cases where the tape112touches the electrostatic elements106,108and is formed from conductive material, the insulating layers104prevent shorting of the electrostatic elements106,108.

The insulating layers400may be formed from a material having a thickness of hundreds of nanometers or less. The material used for the insulating layers400may comprise diamond like carbon (DLC), tetrahedral amorphous carbon (TaC), silicon nitride, silicon dioxide, aluminum oxide, hafnium oxide, silicon carbide.

As opposed toFIG. 1, no air bearing is maintained along the length of the section130of the tape112. Rather, the tape112is in direct contact with the read and/or write element104and parts of the electrostatic elements106,108at the section130. However, the attractive force pushing the section130of the tape112against the head102may be controlled by the controller116(not shown inFIG. 4, but illustrated inFIG. 1). Thus, by choosing the potentials V1, V2applied to the electrostatic elements106,108appropriately, friction between the tape112and the head102can be reduced on the one hand. On the other hand, close enough contact between the tape112and the surface126is ensured for optimal reading and writing.

FIG. 5illustrates in a perspective view a tape head system100according to a further embodiment.

According to the embodiment ofFIG. 5, the head102is formed as a data read and write head. Thus, the head102comprises servo read, data read, and data write elements104(also see the enlargement inFIG. 5). Before and after the read elements104, having regard to the direction of travel110of the tape112, shields500may be arranged. The shields500limit the spatial extent of the magnetic field detected by the read elements104. In order to reduce chemical reactions on the read elements104or the shields500themselves, the shields500may be electrically biased, for example at a potential of less than 1.5 V. Similarly, the pole pieces of the write elements104′ may also be electrically biased, for example at a potential of less than 1.5 V to reduce chemical reactions.

Multiple electrostatic elements106,106′ are arranged alternatingly in the direction of the width w of the head102. The width w corresponds to the direction506crosswise to the direction of travel110of the tape112. Also, electrostatic elements108,108′ are arranged alternatingly in the direction of the width w of the head102. The read and write elements104are arranged in the gap defined between the electrostatic elements106,106′ and108,108′.

The electrostatic elements106are connected to a voltage source118, the electrostatic elements106′ to a voltage source502, the electrostatic elements108to a voltage source120and the electrostatic elements108′ to a voltage source504. Thus, the electrostatic elements106,106′,108,108′ have a voltage V1, V3, V2, V4applied to them, respectively.

For example, the controller116may simply ground the electrostatic elements106,106′,108,108′. In this case, the voltage sources118,502,120,504are set to 0 V (in other words, the voltage sources are not necessarily required). As a result, triboelectric charges, which may result from the tape112contacting the surface126are conducted into the ground and thus taken away. In this manner, friction can be reduced as explained above.

Further, the controller116may control the voltage sources118,502,120,504so as to compensate for a work function of the tape112and the read and write elements104(or other elements for that matter). The work function is a result of two different materials coming into contact, which thus produces a voltage, which in turn may cause attractive forces between the tape112and the head102leading to friction. The work function may be compensated for by applying a voltage to the electrostatic elements106,106′,108,108′ that minimizes the electrostatic attractive force between the tape112and the electrostatic elements106,106′,108,108′.

As another alternative embodiment, the controller116controls the electrostatic elements106,106′,108,108′ so as to dynamically control the distance d2as explained inFIGS. 1 and 4.

The electrostatic elements106and106′ may be merged into a single electrostatic element, to attract the tape112for all read and/or write elements. Also, the electrostatic elements108and108′ may be merged into a single electrostatic element to attract the tape112for all read and/or write elements104.

According to the embodiment ofFIG. 6, the same voltages V2, V4are applied to the electrostatic elements108,108′ in terms of magnitude and polarity. As a result, opposite charges600(so-called image charges) form in the tape112. Consequently, the tape112is attracted towards the head102. At the same time, opposite charges602are formed between the electrostatic elements108,108′. As a result, the substrate114is also at a (positive) potential.

FIG. 7shows an embodiment with a bipolar configuration of the electrostatic elements108,108′.

According to the embodiment ofFIG. 7, voltages V2, V4are applied to the electrostatic elements108,108′ of equal magnitude, yet opposite polarity. Thus, opposite charges600(image charges) are formed in the tape112. However, the opposite charges600in the tape112balance each other out, the tape112thus being at a potential of 0 V.

Also, substantially no opposite charges602are formed between the electrostatic elements108,108′ (as opposed to the embodiment ofFIG. 6).

Further, since the charges on the electrostatic elements108,108′ balance each other out, the substrate114is substantially not charged, i.e., the substrate114is at 0 V.

FIG. 8shows in a perspective view a tape head system100according to a further embodiment.

The embodiment according toFIG. 8differs from the embodiment ofFIG. 5in that the elements104are formed as servo write elements. Each servo write element104comprises, for example, two gaps800for writing a chevron servo pattern on the tape112(not shown).

Having regard to the direction of travel110of the tape112, two pairs of electrostatic elements106,106′ and108,108′ are arranged adjacent to each write element104, thus forming clusters802.

The explanations in connection withFIGS. 5 to 7apply mutatis mutandis to the embodiment ofFIG. 8.

FIG. 9shows in a top view a tape head system100according to a further embodiment.

Again, electrostatic elements106,108and a read and/or write element104are arranged in clusters802on the head102or substrate114. The electrostatic elements106,108may each have a length l9in the direction110of travel between 100 μm and 2 mm. Also, the electrostatic elements106,108may each have a width w9in the crosswise direction506between 10 μm and 500 μm. The length l10of each read and/or write element104may range between 10 μm and 200 μm, for example. The width the read and/or write element104may be equal to or smaller than the width w9of the electrostatic elements106,108, for example.

During reading and writing operations, a controller116(not shown) applies a potential to the electrostatic elements106,108, which results in a warpage of the tape112in a direction506crosswise to the direction of travel110of the tape112. The warpage is comprised of troughs1000forming first sections of the tape112in contact or in close relationship with each read and/or write element104(first section1000′ of the head102). In between the troughs1000, the magnetic tape112comprises ridges1002forming second sections of the tape112spaced apart from the surface126of the head102(second sections1002′ of the head102), thus forming multiple air bearings1004between adjacent clusters802.

In the region of the ridges1002, the surface126of the head102may be formed with concave bevels1006to increase the size of the air bearings1004in a direction perpendicular to the surface226. The bevels1006may each stretch over the entire length l (seeFIG. 9) of the head102.

FIGS. 11 to 14show heads102, each in a top view, according to different embodiments.

According to the embodiment ofFIG. 11, the electrostatic elements106,106′,108,108′ are each formed as stripes arranged, having regard to the direction of travel110of the tape112, before and after the read and/or write element104and extending in the direction of travel110of the tape112. The stripes are arranged parallel to one another in the crosswise direction506.

The electrostatic elements106,108may each have a length l11in the direction110of travel between 100 μm and 2 mm. Also, the electrostatic elements106,108may each have a width w11in the crosswise direction506between 3 μm and 200 μm.

The length l12of each read and/or write element104may range between 10 μm and 200 μm. The width w12of the read and/or write element104may range between 10 μm and 200 μm.

According to the embodiment ofFIG. 12, the electrostatic elements106,106′,108,108′ are formed as stripes arranged, having regard to the direction of travel110of the tape112, before and after the read and/or write element104and extending in the crosswise direction506. The stripes are arranged parallel to one another in the direction of travel110of the tape112.

According to the embodiment ofFIG. 13, the electrostatic elements106,106′,108,108′ are formed as squares, having regard to the direction of travel110of the tape112, before and after the read and/or write element104.

According to the embodiment ofFIG. 14, the electrostatic elements106,106′,108,108′ are arranged, having regard to the direction of travel110of the tape112, before and after the read and/or write element104. In addition, the head102ofFIG. 14comprises electrostatic elements1400,1400′ arranged on the sides of the read and/or write element104facing in the crosswise direction506. Thus, the read and/or write element104is completely surrounded by electrostatic elements. The explanations with regard to the electrostatic elements106,106′ apply mutatis mutandis to the electrostatic elements1400,1400′.

A head102may comprise multiple of the clusters802shown in any one of theFIGS. 11 to 14.

The embodiment ofFIG. 15is largely based on the embodiment ofFIG. 9and shows a head104comprising a plurality of electrostatic elements1500arranged around each cluster802comprising the read and/or write element104and electrostatic elements106,108. The electrostatic elements1500are island shaped. Each of the electrostatic elements1500is grounded by the controller116or otherwise controlled (as described in connection with one of the previous embodiments). The electrostatic elements1500may be configured to reduce wear of the head102and may be formed from metal to this end. In one embodiment, the electrostatic elements1500ensure wear-free operation, and the distances d1, d2, d3, d4(seeFIG. 1) are controlled via the electrodes106,108. The controller116controls the electrostatic elements106,108,1500accordingly.

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects. This is particularly true of the controller116described above. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

More generally, while the present invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiments disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims. In particular, the embodiments ofFIGS. 1 to 15may be combined with one another as required.