Storage Technology Corporation Partners II

Robert P McIntosh

Paul M Romano

Harlan P Mathews

James W Baer

David W Rickert

Majeed Abed

Charles M Reilly

James W Hargarten

Jerry Walker

Henry H Hoshiko

An optical disk storage unit has an improved access and tracking system in which a low speed velocity signal is derived from a differentiated position error signal. The output of the differentiator is applied to a blanking circuit which disconnects the steep slope portion of the position error signal from a sample and hold circuit. A medium speed velocity signal is derived from the integral of motor current and a high speed velocity signal is derived by digitally counting the band crossings in the position error signal.

Optical disk storage unit having a servo system with different velocity

A beam alignment system and method for aligning a first radiation beam with respect to a second radiation beam as these beams share a desired optical path. Beam steering means, such as a galvonometer controlled mirror, steer the alignment of the first beam as it enters the shared optical path. Detection means are employed to sense the relative alignment between the first and second beams as they travel through the shared path. This sensed alignment is compared to a desired alignment, and a position error signal is generated to indicate the error therebetween. The position error signal, in turn, is used to steer the galvonometer controlled mirror in order to force the beam alignment error between the two beams to zero. In a preferred embodiment, the beam alignment system is used in an optical disk storage system to precisely position a write beam a desired distance from a read beam; thereby allowing a data track written with the write beam on a storage disk to be spaced a desired distance (the track pitch) from a previously written track that is being followed by the read beam.

Beam alignment system

A system and method for maintaining a prescribed track pitch in an optical storage system wherein a second radiation beam is aligned a desired distance from a first radiation beam, the first radiation beam being controllably steered to follow a previously written data track on a record carrier used within the optical storage system. A write alignment servo aligns the second radiation beam the prescribed distance from the first radiation beam in response to an offset signal. The offset signal is generated by optically measuring the distance between a pair of calibration tracks that have previously been placed on the disk so as to have the desired track pitch therebetween. The effect of variations or drift occurring in the optical or electrical components of either the write alignment servo or the optical track pitch measurement system is significantly reduced by regularly calibrating against the fixed track pitch of the calibration tracks.

Track pitch calibration system for use in optical storage devices

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Longmont, CO, United States of America

Robert P McIntosh