Browse Prior Art Database

Scanning Light Synchronization System

IP.com Disclosure Number: IPCOM000083661D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Lambiotte, JC: AUTHOR

Abstract

U. S. Patent 3,835,249 describes the use of an optical grating which is swept by a first scanning beam, this scanning beam being a facsimile of a second scanning beam. The optical grating and a photodetector are critically interrelated as described in the patent, and provide position detection or clocking information for the second beam.

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Scanning Light Synchronization System

U. S. Patent 3,835,249 describes the use of an optical grating which is swept by a first scanning beam, this scanning beam being a facsimile of a second scanning beam. The optical grating and a photodetector are critically interrelated as described in the patent, and provide position detection or clocking information for the second beam.

The apparatus described in the patent can be made physically smaller, and the tolerance of the parts can be improved, by the use of a reduction lens in the path of the first beam. This lens arrangement reduces the size of the optical grating and reduces the mechanical tolerances on the elliptical reflector. The grating is scaled such that the photodetector's output remains a measure of the position of the second beam in its larger scan field.

The figure shows a ray of electromagnetic energy 10 incident upon a multifaceted rotating mirror 11. The reflected ray 12 is caused to sweep angle
13. At beam splitter 14 this reflected ray is split into the above-mentioned first and second scanning beams. While utilization of the second scanning beam is not shown, its scanning field is represented by dimension 15.

The above-mentioned first scanning beam 16 passes through spherical lens 17, whereat the scan length is reduced to the length of short optical grating 18. Reflector 19 is a portion of an ellipse, one focal point of which is at point 20, which point is the apparent source of all rays comprising...