Browse Prior Art Database

Microfilm Scanning System

IP.com Disclosure Number: IPCOM000083455D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Potak, DL: AUTHOR

Abstract

Scanning devices 1 and 2 each comprise a monolithic linear array of photodiode elements 3. The photodiode elements are sequentially electronically strobed to provide a series of output signals, corresponding to respective elements of an illuminated linear segment of an image frame 4 on a microfiche card 5. Because they are monolithic, scanning devices 1 and 2 are limited both in absolute length and in linear density of photodiode elements 3. Accordingly, two such devices are needed to obtain a sufficient number of picture elements per line for subsequent display of the scanned frame. The packaging of the arrays prevents devices 1 and 2 from being placed in line, and so they are located in different planes and are offset to opposite sides of the optic axis of the system, as illustrated.

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Microfilm Scanning System

Scanning devices 1 and 2 each comprise a monolithic linear array of photodiode elements 3. The photodiode elements are sequentially electronically strobed to provide a series of output signals, corresponding to respective elements of an illuminated linear segment of an image frame 4 on a microfiche card 5. Because they are monolithic, scanning devices 1 and 2 are limited both in absolute length and in linear density of photodiode elements 3. Accordingly, two such devices are needed to obtain a sufficient number of picture elements per line for subsequent display of the scanned frame. The packaging of the arrays prevents devices 1 and 2 from being placed in line, and so they are located in different planes and are offset to opposite sides of the optic axis of the system, as illustrated.

The remainder of the scanning system comprises a micrometer precision drive 6, an optical path illuminator 7 for illuminating a line segment of image frame 4, and a lens system 8. The whole of the frame 4 is scanned, in a series of line scans, as card 5 is moved in the direction of double-headed arrow 9 by precision drive 6 in synchronism with the strobing of the photodiode elements 3. After passing through lens system 8 the beam is split in beam splitter 10, which directs light to both the scanning devices 1 and 2. The scanning devices are positioned to intercept respective halves of each line segment image.

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