Browse Prior Art Database

Compact Optical Scanner for Optical Facsimile and Optical Printing

IP.com Disclosure Number: IPCOM000050939D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 47K

Publishing Venue

IBM

Related People

Johnson, M: AUTHOR [+2]

Abstract

High numerical-aperture (NA) scanners for light are described in which one or more output prism strips are spiralled about a rotatable drum. Light is coupled from a stationary source to the output prism strips(s) via optical fibers of graded length, which are carried by the drum.

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Compact Optical Scanner for Optical Facsimile and Optical Printing

High numerical-aperture (NA) scanners for light are described in which one or more output prism strips are spiralled about a rotatable drum. Light is coupled from a stationary source to the output prism strips(s) via optical fibers of graded length, which are carried by the drum.

In a laser printer, a scanner is needed to deflect an optical beam over 14" with not more than a 10 percent variation in beam diameter. Such a laser scanner needs a low NA optical system to give the necessary large depth of field. A fiber-optic scanner that can be used in a high-NA system has been described in the IBM Technical Disclosure Bulletin 19, 2286-2287 (November 1976). However, this scanner provides a curved scan. For the purpose of making a compact scanner, it would be nice to have a high-NA scanner system with straight scan lines. This article provides some solutions to meet these requirements.

The concept of this compact optical scanner is illustrated in Fig. 1. An array of (more than 2000) fibers of graded lengths is wrapped around a drum with a diameter D, as shown in Fig. 3. An output prism strip is imbedded in the drum close to the fiber ends. In this example, the locus of fiber ends is a helix of unit- pitch. The detail of this output coupler is given in Fig. 2. Alternative output couplers include optical gratings, individual embossed mirrors, and angle- polished fibers. An optical beam is coupled to one of the fiber inputs at the end of the drum. As the drum rotates, each fiber is illuminated in turn, and an output spot of light scans along a straight generator of the cylinder. The scanned spots are then imaged through a SELFOC(Trademark of Nippon Sheet Glass Co.) lens line array onto the object plane, resulting in a projected line scan. This arrangement provides both a circular to linear transformation and time-sequential scanning.

Each scanner can clearly be used in a reverse mode to transmit information from a document to a single det...