Browse Prior Art Database

Laser Scanner

IP.com Disclosure Number: IPCOM000074320D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Casler, DH: AUTHOR

Abstract

In many optical scanners for character recognition and related purposes it is desirable to have a movable scan head 10 for scanning various portions of a document on a bed 11. Head 10 may be traversed over bed 11 by means of a lead nut 12 running on a driven shaft 13 or by other traversing means. The inclusion of many types of beam-producing apparatus within head 10, however, would render it unacceptably massive, and rapid mechanical motion would be deleterious to many types of beam generators.

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Laser Scanner

In many optical scanners for character recognition and related purposes it is desirable to have a movable scan head 10 for scanning various portions of a document on a bed 11. Head 10 may be traversed over bed 11 by means of a lead nut 12 running on a driven shaft 13 or by other traversing means. The inclusion of many types of beam-producing apparatus within head 10, however, would render it unacceptably massive, and rapid mechanical motion would be deleterious to many types of beam generators.

Accordingly, laser 15 for producing collimated light beam 16 and beam deflector 17 are fixedly mounted on bed 11. Deflected beam 18, having an angle Phi with optical axis 19, is transmitted through focusing lens 20 mounted in one side of head 10, and is then reflected from beam-folding mirror 21 and focused on spot 22 in the plane of bed 11. Diffuse reflected rays 23 reach photodetector 14, either directly or via curved reflective surface 24.

The position of focused spot 22 in the focal plane of lens 20 is specified by the relation x=f tan Phi, where f is the focal length of the lens and x is the distance of the spot 22 from optical axis 19. Since this relation does not depend upon the distance between deflector 17 and lens 20, scan head 10 may be moved along shaft 13 without affecting either the spot size or the scan height, as long as all of the light from beam 18 enters lens 20.

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