Browse Prior Art Database

Mark Sense Read Head

IP.com Disclosure Number: IPCOM000093957D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Reinhart, FM: AUTHOR

Abstract

Degradation of optical reading of tape marks because of spectral reflection of the tape illumination is prevented by orientation of the illuminating sources relative to the tape surface.

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Mark Sense Read Head

Degradation of optical reading of tape marks because of spectral reflection of the tape illumination is prevented by orientation of the illuminating sources relative to the tape surface.

Characters on tape 10 are to be optically read by read head 14. Tape 10 can be a stenographic tape and have fan fold creases such as 11. Baffels in 14 can permit reading each channel on 10 by a separate photodiode. Illumination sources 15 and 16 are arranged so that the angle of incidence of the light 17 and 19 relative to the surface of 10 is below the critical angle which causes spectral reflection into 14. In practice, an angle of incidence between 30 degrees and 45 degrees for light rays 17 and 19 with respect to 10 is sufficient. As a result, reflected rays 18 are diffused light and spectral reflection is avoided.

Locating 15 and 16 at the sides of 10 prevents creases or folds such as 11 from causing momentary spectral reflection into 14 as 11 passes under 14. No significant change in the diffused light 18 results and 14 can read marks across
11.

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