Browse Prior Art Database

Improved Fiber Optic Read Head

IP.com Disclosure Number: IPCOM000093961D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Sokolski, M: AUTHOR

Abstract

Fiber optic read head 10 for sensing marks 11 on document 12 is constructed with light transmitting and receiving fiber bundles 15 and 20. There is one bundle pair for each sensing position. Each bundle pair is set at an angle to provide a prismatic effect so that the illuminating rays strike 12 at approximately 20 degrees off normal. The ends of 15 and 20 facing 12 are parallel to and recessed from surface 25 of housing 26 a distance so as to provide a constant optical path from the ends of 15 and 20 to the document plane. The distance from surface 25 to the document plane is preferably zero. To permit variations in paper thickness and double documents, a spacing slightly larger than one document is provided.

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Improved Fiber Optic Read Head

Fiber optic read head 10 for sensing marks 11 on document 12 is constructed with light transmitting and receiving fiber bundles 15 and 20. There is one bundle pair for each sensing position. Each bundle pair is set at an angle to provide a prismatic effect so that the illuminating rays strike 12 at approximately 20 degrees off normal. The ends of 15 and 20 facing 12 are parallel to and recessed from surface 25 of housing 26 a distance so as to provide a constant optical path from the ends of 15 and 20 to the document plane. The distance from surface 25 to the document plane is preferably zero. To permit variations in paper thickness and double documents, a spacing slightly larger than one document is provided.

Recess 27 is filled with a transparent epoxy resin to prevent accumulation of dust and provide a surface flush with 25. In this manner, documents 12 tend to wipe 10 clean as they pass relative to it.

Single light source 13 furnishes light to all bundles 15 for each sensing position. This results in an illuminating area B at each position. Bundles 20 have a viewing area A. However, only light reflected within common area C is directed by bundles 20 to photo transistors 21 from which output signals are taken. High intensity illuminating rays 17 are reflected out of the viewing area of 20. This enables a high signal output when sensing glossy marks.

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