Browse Prior Art Database

Scanner Assembly

IP.com Disclosure Number: IPCOM000077627D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Luderus, FJ: AUTHOR

Abstract

A light-emitting diode (LED) array is used as a light source in an optical scanner. The scanner generates video input for a character recognition system. Since the efficiency of light-emitting diodes differs from one diode to another, a reference signal is needed for comparison with the light reflected from the document to be scanned.

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Scanner Assembly

A light-emitting diode (LED) array is used as a light source in an optical scanner. The scanner generates video input for a character recognition system. Since the efficiency of light-emitting diodes differs from one diode to another, a reference signal is needed for comparison with the light reflected from the document to be scanned.

A row of sequentially energized light-emitting diodes 1 is imaged through lens system 3 on document 7. Signal detector 6 collects light reflected from the document.

The intensity distribution of a LED approaches between 30 degrees and 70 degrees that of a Lambert source. Thus a reference detector 2, identical to signal defector 6, collecting light outside the solid angle from light source to lens, generates a reference signal that has a linear relationship to the light transmitted through lens 3.

The scanner assembly is mounted in frame 5, and for focussing purposes adjustable through means 4.

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