Browse Prior Art Database

Scanning Method Employing Multiple Flying Spots Per Field

IP.com Disclosure Number: IPCOM000077887D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Belleson, JG: AUTHOR

Abstract

A method is provided for obtaining high-speed scanning in an optical scanner that uses a rotating mirror having a relatively small size,, and also employs a fiber-optics bundle.

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Scanning Method Employing Multiple Flying Spots Per Field

A method is provided for obtaining high-speed scanning in an optical scanner that uses a rotating mirror having a relatively small size,, and also employs a fiber-optics bundle.

Laser beam 11 from source 13 passes through multiple beam forming optics 15, which splits the laser beam into several beams- 17 that are directed toward one facet 19 of rotating mirror 21 at different angles of incidence. This produces multiple scanning spots which are focused simultaneously onto the field 22 by lens 23. The multiple spots are detected by a leading edge detector 25 and interdigitated fiber-optics bundles 27, which terminate into photodiodes 29.

With the multiple interdigitated detector arrangement, it is possible to electronically follow each spot across the field, i.e., the first spot being detected by the first detector, then by the second detector, etc. Since the spots move at a uniform velocity and can be detected when they pass across leading edge detector 25, it is possible to determine when to switch from one detector to another detector.

The input end of the fiber-optic array must be near enough to the scanned field, so that a spot within the area detected by detector No. 1 does not leak light into detector No. 3, etc., i.e. so the crosstalk is small enough. Other parameters which effect the crosstalk are the separation between detectors (e.g. Nos. 1 & 3), and the point at which one switches from detectors...