Abstract: In one aspect, a trifocal ophthalmic lens is disclosed that includes an optic having a surface that comprises at least one trifocal diffractive pattern and at least one bifocal diffractive pattern such that the bifocal pattern provides near and far vision and the trifocal pattern generates near, far, and intermediate vision. For example, the trifocal pattern can provide near, far, and intermediate foci such that the near and far foci are substantially coincident, respectively, with a near and a far focus of the bifocal pattern. In this manner, the trifocal and bifocal patterns collectively provide near, intermediate, and far foci (or focal regions) corresponding, respectively, to the near, intermediate and far vision.

Abstract: A method for calculating the required cylindrical power of a toric implant by using both the measured pre-operative corneal/ocular astigmatism and the predicted surgically-induced astigmatism. The post-operative corneal/ocular astigmatism is predicted using power vector analysis of the surgical technique employed by the surgeon. Such a method provides a more accurate method of calculating the required spherocylindrical refractive power of the implant. The method can be implemented manually, but preferably is automated by implementation on a computer through appropriate software.

Abstract: A CPP magnetic sensor is disclosed with a ferromagnetic layer that extends in a first direction a first distance; a nonferromagnetic spacer layer that adjoins the ferromagnetic layer and extends in the first direction a second distance that is substantially equal to the first distance; and a ferromagnetic structure that is separated from the ferromagnetic layer by the spacer layer, the ferromagnetic structure having a first section that extends in the first direction a third distance that is substantially equal to the second distance, the ferromagnetic structure having a second section that is disposed further than the first section from the spacer layer, the second section extending at least twice as far as the first section in the first direction. The ferromagnetic structure can be used for in-stack bias or pinning of free or pinned layers, respectively, and side shields can be provided for high areal density.

Abstract: A method to fabricate a tunneling magnetoresistive (TMR) read transducer is disclosed. An insulative layer is deposited on a wafer substrate, and a bottom lead is deposited over the insulative layer. A laminated TMR layer, having a plurality of laminates, is deposited over the bottom lead. A TMR sensor having a stripe height is defined in the TMR layer, and a parallel resistor and first and second shunt resistors are also defined in the TMR layer. A top lead is deposited over the TMR sensor. The parallel resistor is electrically connected to the bottom lead and to the top lead. The first shunt resistor is electrically connected to the bottom lead and the wafer substrate, and the second shunt resistor is electrically connected to the top lead and the wafer substrate.

Abstract: A magnetic head for writing information on a relatively-moving medium includes a first substantially flat soft magnetic pole layer and a second substantially flat pole layer with at least one coil layer between them. The pole layers are magnetically coupled in a core region and spaced by more than one micron from one other. A soft magnetic pedestal adjoins the first pole layer adjacent to a medium-facing surface of the head, and a first high magnetic saturation layer adjoins the pedestal. A second high magnetic saturation layer adjoins the second pole layer. The first high magnetic saturation layer has a first throat height and the second high magnetic saturation layer extends from the medium-facing surface only to a second throat height. The first and second throat heights are within about one and one-half microns from the medium-facing surface and are essentially equal.

Abstract: A method for subaperture polishing includes determining a first portion of a sample to be polished disproportionately compared to a second portion of the sample. Based on the determination of the first portion, a sweep frequency that is a first rate of lateral motion for a polishing pad is selected to be substantially equal to an integer multiple of a rotation frequency that is a rate of rotation for the sample. The method further includes rotating the polishing pad at the polishing frequency, rotating the sample at the rotation frequency, and polishing the sample using the polishing pad while rotating the polishing pad and the sample.

Abstract: A system and method for the production level screening of low flying magnetic heads in the manufacture of disk drive head disk assemblies (HDAs) is disclosed. A test disk is provided and has a plurality of bumps extending from at least one surface thereof. The test disk is rotated to fly a head of a head gimbal assembly selected from the group adjacent the surface of the test disk. An interaction of the head with one or more of the plurality of bumps may be sensed and the head gimbal assembly may be screened out from the group in response to the sensing of the interaction.

Abstract: A method of receiving data at a client computer and performing an operation on the received data is disclosed. The method comprises: receiving a key file having a rule identifying the operation to be performed on the data received at the client computer; receiving the data at the client computer; and performing the operation identified by the rule in the key file on the data received at the client computer.

Abstract: A disk drive is disclosed having hybrid spindle speed control. The disk drive includes a disk having a plurality of servo wedges, and a spindle motor for rotating the disk at an operating speed. The spindle motor generates a back electromotive force (BEMF) voltage. In operation, the disk rotation is maintained at the operating speed during a track following operation by updating, in a wedge spindle speed control mode, the spindle control current in response to a wedge speed error. Before executing a high-speed seek, the disk drive is switched to a BEMF spindle speed control mode, and the disk rotation is maintained at the operating speed during the high speed seek by updating the spindle control current in response to a BEMF speed error signal generated based on the BEMF voltage. During a seek-settle time, the disk drive is switched back to the wedge spindle speed control mode.

Abstract: A write element for perpendicular recording in a data storage system is fabricated to maintain the thickness of a side shield at both edges of a pole P3, and to form the pole P3 in a trapezoidal shape. Forming a side shield around the pole P3 removes stray fields, creating a quiet, noise-free write element and preventing side erasure. The fabrication method utilizes a magnetic buffer layer to protect a shield gap during trim of the pole P3, and thus to provide the shield gap with a uniform thickness. The magnetic buffer layer also protects the shield gap and pole P3 when the top hard mask is removed. Consequently, the write field is made uniform across the track width. The fabrication method uses a metal in the shield gap to improve the pole geometry after pole trim and to provide a uniform edge to the pole P3.

Abstract: A read element includes a magnetoresistive sensor having a side and an upper surface that defines an edge. An underlayer overlies the side of the magnetoresistive sensor, and a hard bias layer overlies at least part of the underlayer and defines a hard bias junction with the underlayer. A lead is formed atop the hard bias layer. The hard bias junction is recessed from the edge of the magnetoresistive sensor by a predetermined recess distance, to provide stability and sensitivity to the read element.

Abstract: A disk drive is disclosed having a servo control system optimized for faster determination of repeatable runout (RRO) correction values. Each circumferential track on a magnetic disk exhibits total runout having an RRO component and a nonrepeatable runout (NRO) component. The control system generates a control signal for positioning a transducer head during a track following operation based on distributed position information defining the followed track. PES values are calculated based on the distributed servo position information read during a track following operation. The first servo-loop compensator processes the PES values during normal data access operations and has a first transfer function that is optimized with respect to a variance of the total runout. The second servo-loop compensator processes the PES values during a RRO calibration operation and has a second transfer function that is optimized with respect to a variance of the NRO component.

Abstract: A method for reducing the length of servo-wedges in a disk drive comprising a concentric tracks, each track comprising embedded servo-wedges each having a track identification field (TIF) and a servo-wedge identification field (WIF), wherein the embedded servo-wedges are grouped into servo-wedge groups comprising a first and second sub-group of servo-wedges. The method includes selecting a servo-wedge from a selected servo-wedge group; storing a first subset of a track identification data (TID) corresponding to a selected track in TIF of selected servo-wedge; storing a second subset of TID in a first portion of WIF of selected servo-wedge if selected servo-wedge is in second sub-group; storing a first wedge identification data (WID) corresponding to selected servo-wedge in a second portion of the WIF if selected servo-wedge is in second sub-group; and storing a second WID corresponding to selected servo-wedge in WIF if selected servo-wedge is in first sub-group.

Abstract: A disk drive is disclosed having a disk comprising a plurality of spiral tracks, a head actuated over the disk, and control circuitry operable to process the spiral tracks in an interleaved manner to write a plurality of product servo sectors to the disk to define a plurality of radially spaced, concentric data tracks.

Abstract: In a method and system for reducing power consumed by a magnetic memory, magnetic memory cells are coupled to a bit line and are associated with a plurality of digit lines. A bit line current is provided in the bit line. Digit currents are provided in parallel in the digit lines at substantially the same time as the bit line current. The digit and bit line currents allow the magnetic memory cells to be written to a plurality of states in parallel.

Abstract: A method for reducing a servo channel head gain calibration time comprising initiating a servo channel head gain calibration process for a head corresponding to the selected disk surface; obtaining a head gain calibration value for a pre-selected zone in the selected disk surface; comparing the obtained calibration value with a pre-stored calibration value for the pre-selected zone and generating a comparison result; and stopping the calibration process for the head if the comparison result does not exceed a threshold value.

Abstract: A disk drive is disclosed comprising a disk, a head, and a voice coil motor (VCM) for actuating the head over the disk. The disk drive executes a rotational position optimization (RPO) algorithm to select a next command to execute relative to an estimated seek time computed for each command in a command queue. A seek time parameter is estimated and a seek time delta computed in response to the estimated seek time parameter. The seek time delta is added to a nominal estimated seek time to generate a modified estimated seek time for each command in the command queue, thereby optimizing the RPO algorithm.

Abstract: A method for manufacturing a reader/writer is provided having a substrate with an undercoat formed thereon. A first shield is formed over a portion of the undercoat and a pair of reader leads is formed over the first shield and undercoat. A read sensor is formed between the reader leads and a first pole/second shield is formed over the reader leads. A mid coat is formed over the undercoat and the reader leads. A second pole is formed over and in contact with the mid coat. A lead is formed over the second pole. A pedestal is formed over the reader lead and an overcoat is formed over the second pole and the lead and around the pedestal. A pad is then formed over the pedestal.

Abstract: A system and method for processing track identification data in a disk drive having concentric tracks each having a track identification field (TIF) stored in embedded servo sectors, the TIF includes a band segment identifying a group of tracks, and an index segment identifying a single track of the group of tracks. The system and method include reading a servo sector to obtain the TIF, parsing the TIF to obtain the band segment, comparing the obtained band segment to an expected band segment to obtain a band segment differential (BSD), initiating an action if the BSD exceeds a pre-determined threshold and varies from the expected band segment by a predetermined number of bits, initiating another action if the BSD exceeds the predetermined threshold and does not vary from the expected band segment by the predetermined number of bits. The process is then applied to the index segments of the band segment.

Abstract: The invention relates to a disk drive and related method for improved disk rotation rate control in the presence of seek operations. A spindle motor rotates a spindle, supporting at least one disk with a magnetic recording surface, in response to a motor current. The actuator radially positions a transducer head over the recording surface. The motor is subjected to a torque load component related to the transducer head radial position. The spindle motor controller has a feedback control loop and a feedforward control element. The feedback control loop maintains a relatively constant spindle rotation rate based on a difference error between a predetermined target spindle rotation rate parameter and a measured spindle rotation rate parameter. The feedforward control element, in conjunction with a seek operation, adjusts the motor current based on a target head radial position with respect to an initial head radial position.