Maxtor Corporation

Displaytech, Inc.

Stephen H Perlmutter

Don Brunnett

Thomas O Melrose

Lloyd E Levy

James W Hargarten

Adrián Cerdá

Jiuzhi Xue

Richard Edward Martin

Robert Dean Turner

Charles M Crandall

Christine Green

Beth L Ellis

Devon Dallmann

An optical device includes a ferroelectric liquid crystal material. This optical device has a first and a second substrate. A first alignment treatment is applied to a surface of the first substrate, the first alignment treatment being intended to induce an orientation of at least a portion of the ferroelectric liquid crystal material along a first alignment direction with a first pretilt angle &#x3b1;with respect to a plane parallel to the first substrate. A second alignment treatment is applied to a surface of the second substrate, the second alignment treatment being intended to induce an orientation of at least another portion of the ferroelectric liquid crystal material along a second alignment direction with a second pretilt angle &#x3b1;with respect to a plane parallel to the second substrate. The optical device further includes an arrangement for securing the first substrate with respect to the second substrate in such a way that the surfaces of the first and second substrates onto which the first and second alignment treatments were applied, respectively, are spaced apart, generally parallel and facing each other. In addition, a projection of the first alignment direction onto the treated surface of the first substrate makes a non-zero angle &#x3a9; with respect to a projection of the second alignment direction onto the treated surface of the first substrate such that, the ferroelectric liquid crystal material being injected between the first and second substrates, the optical device is free of chevron structures without a need to otherwise apply an additional treatment to the optical device.

Chevron-free FLC device

In some embodiments of the present invention, a disk drive includes a rotatable data storage disk, a head, and a controller. The head is configured to fly on an air cushion relative to a data recording surface of the rotating disk while writing data to the data recording surface responsive to a write command from a host device or while reading data from the data recording surface to generate a read signal responsive to a read command from the host device. The controller is configured to measure flying height of the head relative to the data recording surface of the disk in response to sensing power-up of the disk drive and/or a shut-down command from the host device. The controller may measure the flying height in response to sensing power-up of the disk drive and, subsequent to measuring the flying height, may generate a ready signal to the host computer that indicates that the disk drive has powered-up and is ready to receive read/write commands from the host computer.

Methods and disk drive that measure head flying height at power-on/off

A disk drive measures the radial misposition of tracks and repositions the tracks at regularly spaced intervals. Written in runout (WRO) in servo bursts is determined to calculate track spacing and squeeze among adjacent tracks. Tracks with improper spacing are repositioned by adding a squeeze correction term to the servo wedges. Thereafter, when the disk drive operates to store data, the servo bursts are used to calculate a position error signal (PES), and the squeeze correction term is combined with the PES to position the head at a proper track radius.

Method to correct radial misposition of data tracks using stitched correction fields

Method to correct radial misposition of data tracks

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Lafayette, CO, United States of America

Stephen H Perlmutter