Browse Prior Art Database

High Efficiency Light Collection System for Optical Scanners

IP.com Disclosure Number: IPCOM000077041D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Bartz, MR: AUTHOR [+2]

Abstract

This system provides an efficient means of collecting light scattered from a document or other reflective surface being scanned by a light beam, for purposes of extracting information from the object being scanned. The beam scans the surface along a straight line fixed with respect to the collection system and in which the video information is continued primarily or completely in the nonspecular (diffuse) portion of the reflected light. The collection efficiency of this system is nearly constant eliminating the problem of "baseline bow" inherent in most present day scanners.

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High Efficiency Light Collection System for Optical Scanners

This system provides an efficient means of collecting light scattered from a document or other reflective surface being scanned by a light beam, for purposes of extracting information from the object being scanned. The beam scans the surface along a straight line fixed with respect to the collection system and in which the video information is continued primarily or completely in the nonspecular (diffuse) portion of the reflected light. The collection efficiency of this system is nearly constant eliminating the problem of "baseline bow" inherent in most present day scanners.

Beam-splitter 1 splits light beam from light-emitting diode (LED) array 2 so that one part is impinged on phototransistor 3 and the other part is transmitted to lens 4. The circuit comprised of phototransistor 3 and transistor 14 provide a signal to monitor the light intensity of the source LED. Lens 4 causes light beam to be focused at C on document.

Mirror 5 is a section of one elliptical cylinder having focal lines at (C) and (D). Mirror 6 is a section of a second elliptical cylinder with focal lines at (C) and (E). Fiber bundles 7 & 8 are located with their input windows at (D) and (E) and can be coupled either to separate detectors, not shown, or brought together to couple into one detector.

Light detector 9 (phototransistor) in conjunction with transistor 10 provides the document video signal. Discrete LED 11 light biases phot...