The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 13, 1983
Filed:
Jul. 20, 1981
John H Jacobs, Altadena, CA (US);
Bell & Howell Company, Chicago, IL (US);
Abstract
Methods and apparatus for reading information from a record with the aid of a plurality of electrically controlled light gates illuminate the light gates with light of a first intensity above zero light intensity and precondition the light gates to subsequent opening in response to electric control signals by electrically biasing the light gates to an initially open condition wherein the gates pass light from the illumination at an intensity above zero light intensity and below a second intensity lower than the first intensity. These methods and apparatus also subject the record to a first illumination by said light of an intensity above zero light intensity and below the second intensity as passed by the preconditioned gates in the initially open condition, subject the record to a second illumination by further opening the preconditioned light gates in response to electric control signals to pass light at at least the second light intensity and scan the record with the passed light at at least the second intensity, and read information from the record only in response to the second illumination as among the first and second illuminations.