Browse Prior Art Database

Scanner Using Linear Array of Light Emitting Diodes

IP.com Disclosure Number: IPCOM000077038D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Baxter, DW: AUTHOR

Abstract

Scanner body 10 is a small, inexpensive, rugged and efficient scanner for use in character recognition and related systems. A linear array 11 of light-emitting diodes is mounted in or on base plate 12, which also carries a number of electrical connections 13. Light ray 14 from one of the diodes in array 11 is focused into small spot 15 on a document plane by lens system 16 in lumen 17 of cylindrical body 18. Cylindrical plate 19 is a thin transparent dust cover affixed to body 18. Diffuse reflected rays 20 from point 15 impinge directly upon large-area photodetector 21 mounted on one wall of a substantially rectangular cross section chamber 22. An opposite end wall of chamber 22 is provided with curved reflective surface 23 so that diffuse rays 24 are further reflected to the sensitive surface of detector 21.

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Scanner Using Linear Array of Light Emitting Diodes

Scanner body 10 is a small, inexpensive, rugged and efficient scanner for use in character recognition and related systems. A linear array 11 of light- emitting diodes is mounted in or on base plate 12, which also carries a number of electrical connections 13. Light ray 14 from one of the diodes in array 11 is focused into small spot 15 on a document plane by lens system 16 in lumen 17 of cylindrical body 18. Cylindrical plate 19 is a thin transparent dust cover affixed to body 18. Diffuse reflected rays 20 from point 15 impinge directly upon large- area photodetector 21 mounted on one wall of a substantially rectangular cross section chamber 22. An opposite end wall of chamber 22 is provided with curved reflective surface 23 so that diffuse rays 24 are further reflected to the sensitive surface of detector 21. The flat substantially parallel side walls 25 of chamber 22 are also provided with a reflective coating for the same purpose. An upper portion of body 18 contains second chamber 26 having a configuration similar to that of chamber 22. Monitor photodetector 27 receives off-axis light rays 28 from LED array 11, either directly or from curved deflector 29. Side walls 30 of chamber 26 are also coated with a reflective material to enhance light collection by detector 27. The necessary electrical connections from array 11 and photodetectors 21 and 27 are made internally to pins 13 in base 12.

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