Seagate Technology Incorporated

Western Digital Technologies, Inc.

Other

Jp Morgan Chase Bank

Photonics Corporation

Lasertape Systems, Inc.

Lawrence Matthias Bryant

David S Kuo

Karl Arnold Belser

Sundeep Chauhan

Neil Deeman

Christopher Formato

Siri S Weerasooriya

Eric G Rawson

Robert Dale Murphy

David Shiao-Min Kuo

Alan A Fennema

Yakov M Lifchits

Charles A Bates

Gabor Szita

Charles A Park

David R Rodal

Wing Ying

Yun Hong

John H Richards

James W Dickson

Gabor Sz&iuml;ta

A disk drive is disclosed comprising a first head actuated over a first disk surface and a second head actuated over a second disk surface. A first servo sector of the first disk surface is read to generate a read signal which is processed to generate a first phase error. A first clock is generated at a frequency proximate a servo data rate of the first data sector. Read signal samples are synchronized in response to the first phase error and the first clock to generate synchronous samples, and servo data in the first servo sector is detected in response to the synchronous samples. The read signal is processed to generate a second phase error, a second clock is generated in response to the second phase error, and a spiral servo track is written to the second disk surface using the second clock.

Servoing on zoned concentric servo sectors of a first disk surface to write a spiral servo track to a second disk surface

A disk drive is disclosed comprising a disk, and a head actuated over the disk. The head is positioned at a radial location over the disk, and a servo burst is written at the current radial location. The servo burst is read to generate a read signal, and the read signal is processed to generate a position error signal (PES). The head is moved radially in response to the PES, and the process is repeated multiple times to form a spiral track spanning at least one revolution of the disk.

Disk drive self servo writing spiral tracks by propagating bursts

A disk drive is disclosed comprising control circuitry for self servo writing a disk. An estimated reader/writer offset is initialized, servo bursts in a first servo track are read, the head is moved radially using the estimated reader/writer offset, and propagated servo bursts are written to a target servo track. The propagated servo bursts are read from the target servo track to generate a read signal, the read signal is processed to generate a burst crossing signal (BCS), and the estimated reader/writer offset is adjusted in response to the BCS.

Disk drive adjusting estimated reader/writer offset to achieve target burst crossing signal amplitude when propagating servo sectors

Embodiments of the invention generally provide an electron beam substrate processing system. In one embodiment, the present invention provides an electron beam substrate processing system where a spindle shaft used to rotate substrates during processing includes at least one optical encoder wheel assembly. The optical encoder wheel assembly is configured to provide rotational speed data signal to a rotational speed control system and a pattern generation clock circuit configured to a provide an angular pattern generator clock signal and to a pattern generator circuit. The pattern generation circuit is configured to control modulation of an electron beam used for substrate processing. In one aspect of the present invention, while the spindle shaft is rotated at a constant linear velocity, the pattern generation circuit controls the modulation of an electron beam such that written mark lengths are sized to be about constant in angular dimension.

Method and apparatus for constant linear velocity electron beam substrate processing

A rotating recording device, such as an electron beam recorder, is provided with a dual encoder arrangement. A first encoder is employed as a spindle motor controller and located at a first end of a spindle. A second encoder is mounted at a turntable adjacent to a recording surface and used as a position, velocity or clock source for recording the pattern on the substrate. Eccentricity of the mounting of the second encoder is measured against the more accurately mounted spindle control encoder and compensated by a digital clock generating system using a digital phase locked loop.

Rotating recorder with dual encoder arrangement having eccentricity compensation

A servo writing system for writing servo sectors onto a disk includes a direct digital synthesizer (DDS) that forms a phase and frequency adjustable continuous wave signal based upon a reference digital clock signal. A PLL coupled to the DDS measures repeatable timing errors (RTEs) associated with the continuous wave signal and generates an output clock signal that is used to clock the writing of servo sectors onto the disk. A digital control system is coupled to the DDS and the PLL, which calculates repeatable error compensation adjustment values based on the RTEs measured using the PLL. The compensation adjustment values may be applied to the DDS such that the DDS compensates for the RTEs and such that the output clock signal used to clock the writing of the servo sectors onto the disk includes minimal RTEs.

Repeatable timing error correction system for use in a servo writer

Embodiments of the invention generally provide an electron beam substrate processing system. In one embodiment, the present invention provides an electron beam substrate processing system where a spindle shaft used to rotate substrates during processing includes two encoder wheels. One encoder wheel is configured to provide a rotational speed data signal to a rotational speed control system. Another encoder wheel is configured to provide a pattern generator clock signal at a higher frequency than the rotational speed data signal to a pattern generator. In one embodiment of the present invention, at least one of the encoder wheels is positioned adjacent the substrate to minimize torsional and differential movements between the at least one encoder wheel and the substrate.

Method and apparatus for electron beam processing of substrates

Embodiments of the invention generally provide an electron beam substrate processing system. In one embodiment, the present invention provides an electron beam substrate processing system where a spindle shaft used to rotate substrates during processing includes at least one optical encoder wheel assembly. The optical encoder wheel assembly is configured to provide rotational speed data signal to a rotational speed control system and a pattern generation clock circuit configured to a provide a corrected pattern generator clock signal to a pattern generator circuit. The pattern generation circuit is used to control modulation of an electron beam used for substrate processing. In one aspect of the present invention, repeatable deviations of the rotational speed are measured and processed during substrate processing to correct for such repeatable deviations to increase substrate pattern writing accuracy.

Method and apparatus for a formatter following electron beam substrate processing system

A disc drive with an information portion previously written on a rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing a reference mark to the rotatable disc surface in substantial time alignment and phase and frequency coherent with the information portion previously written to the rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing the reference mark, a pulse detector circuit for creating logic level signals from the reference mark, a pattern generator for generating reference mark write signals from the logic level signals, a memory buffer for storing radial position correction tables and values for writing the reference mark, and a self-servo control and sequencing circuit synchronizing timing signals for writing the reference mark to rotatable disc surface of disc drive.

Self-writing servo and clock fields on a recording medium

A propagating method is provided in which timing and servo sector information is propagated throughout a data storage media that initially contains only a guide pattern. The method uses an offset between the write element and the read element in a read/write head to position and propagate the timing information. In addition, a method for circumferentially aligning timing and servo sector information is disclosed that utilizes a time delay to position the propagated timing and servo sector information. Another method for attenuating timing errors during timing and servo sector propagation to a data storage media is disclosed. Timing errors are attenuated through the use of phase locked loop circuit and measurement of the phase error detected between different tracks on the data storage media. Apparatuses implementing the methods including a storage device readable by a computer system that implements the methods are provided.

Circumferential positioning of servo sectors for servo track writing

A method and apparatus for reading and writing data from and to a data storage disc in a data storage device. The data storage disc includes a first disc surface and second disc surface for storing data. The data storage device includes an actuator assembly configured to selectively position a first transducer over the first disc surface and a second transducer over the second disc surface, wherein the first transducer is substantially identical to the second transducer. Furthermore, each transducer includes a read element and a write element, wherein the read element is offset from the write element by at least the width of one servo track.

Servo writing in a disc drive with substantially identical heads having read and write elements in a radial offset position

An apparatus and method for sensing the position of a read/write head or transducer carried by a microactuator at a distal end of a primary actuator in a head disc assembly of a disc drive. The position sensing system has a fixed member attached to the primary actuator and a moveable member attached to the fixed member by an attachment device. The attachment device permits the moveable member to move in relation to the fixed member along a predetermined pathway. A secondary voice coil motor (VCM) drives the movement of the microactuator via a VCM coil that is affixed to the moveable member, wherein a high frequency signal is applied to the VCM coil. At least one sense coil is attached to the fixed member and positioned near the VCM coil, such that the sense coil will receive a portion of the high frequency signal transmitted from the VCM coil through mutual magnetic coupling. The magnitude of magnetic coupling at the sense coil will provide a position measurement of the VCM coil of the microactuator, and thus the transducer, relative to the primary actuator.

Position sensing system for disc drive magnetic microactuators

A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the invention describes a magnetic disk drive employing a laser system to form and sense optical clock patterns placed on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder. Additionally, the laser system may also be used to form textured surfaces on a disk to control the flying characteristics of a magnetic head slider assembly. These textured surfaces may also serve as a resting area for the magnetic head slider assembly when the disk is not spinning.

Method and apparatus for optically sensing accurate clock patterns

The present invention is used to form precise, optically detectable patterns on rotating members of a disk and spindle assembly of a disk drive used in data storage system. In particular, the invention employs an optical source to form optically detectable patterns on the rotating members of the disk drive. These optically detectable patterns are used to create an accurate clock track. The clock track may be used to create multiple accurate magnetic patterns on one or more disks attached to a disk and spindle assembly in a magnetic data storage system. By successively changing the radius at which the magnetic patterns are created it is then possible to create multiple magnetic patterns at successive radii with all such magnetic patterns having a precise geometric relationship to each other. Alternatively, the accurate clock pattern may stand alone as an encoder. Additionally, the present invention may also be used to form textured surfaces on a disk to control the flying characteristics of a magnetic head slider assembly. The present invention can also create textured surfaces which will serve as a resting area for the magnetic head slider assembly of a magnetic disk drive when the disk is not spinning.

Method and apparatus for forming accurate optical clock patterns

A system and method are provided for processing signals in a magneto-optical computer memory device to detect mispositioning of a head with respect to a track centerline. A light beam is scanned over a first and a second set of radially offset optically-detectable position marks formed in the rotating medium surface. A detector receives the reflected light beam and responsively generates a position signal having a plurality of pulses corresponding to the position marks. The position signal is then passed through a differentiator circuit. The differentiated position signal may then be applied to low pass filter and resonator circuits, and is subsequently conveyed to a finite time integrator for rectification and detection of the areas of the pulses associated with the first and second set of position marks. Mispositioning of the head is detected by comparing the pulse areas of the first and second set of position marks.

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Palo Alto, CA, United States of America

Lawrence Matthias Bryant