E-systems, Inc.

Jeffrey P Welch

John D Boardman

Scott M Hamilton

James R Boyd

Richard A Trimble

Jimmie L Sadler

Mervin L Gangstead

An optical system for scanning a light beam across an object where the light beam is double reflected by the reflection surfaces of a rotating polygonal mirror. Beam expander optics are included in the light path for the light beam following the first reflection by the polygonal mirror to magnify the beam diameter to fill the length of the reflective surface of the polygonal mirror at the second reflection. The beam expander optics further include lenses for demagnifying scan angle in the light beam following the first reflection. The lenses of the beam expander optics are formed with a Petzval curvature (third order Seidel aberration) to correct for the distortion induced in the optics image plane by the longitudinal shift in the entrance pupil position at the first reflection as the polygonal mirror rotates.

Polygonal mirror optical scanning system

The optical tape recorder of the present invention is capable of archiving data at rates in excess of 400 megabits per second by concurrently writing or reading a plurality data tracks in each data trace. A read-write module outputs an illumination beam comprised of combined multiple write beams (channels), a read beam and an autofocus beam. Optics within the read-write module spatially combine and accurately position the plurality of beams with respect to each other to form the multi-beam illumination beam. A read-write head comprised of a synchronized scanning transmissive polygon and rotating lens wheel scans the multi-beam illumination beam across a recording media to read or write multi-channel data tracks. An autofocus system is also included to ensure that the multi-beam illumination beam is accurately focused on the recording media.

Optical recorder and reader of data on light sensitive media

The present invention provides a read-write head for an optical tape recorder comprised of a synchronized scanning transmissive polygon and rotating lens wheel. The transmissive polygon is a multi-sided piece of transparent optical quality material for displacing a through transmitted collimated read or write light beam. The lens wheel comprises a unitary disk-shaped piece of optical quality material having a plurality of individual lenses precision molded or diamond point turned therein for focusing the through transmitted and displaced read or write light beam onto a recording media. The polygon is rotated to translate the displaced beam for scanning along a linear path aligned with an arcuate path followed each successive lens on the rotating lens wheel. The rotation of the polygon and lens wheel are synchronized such that each scan of the displaced beam along the linear path coincides with the movement of a lens along the arcuate path to trace out a data track on the recording media. A pair of beam expanders are also provided in the read-write head as a demagnification-magnification system around the transmissive polygon to improve system performance by narrowing the diameter of the beam transmitted through the polygon.

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Plano, TX, United States of America

Jeffrey P Welch