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:
May. 18, 1993
Filed:
Nov. 20, 1990
Christopher J Wittensoldner, Cambridge, OH (US);
Denis M Blanford, Cambridge, OH (US);
John K Burkey, Cambridge, OH (US);
Paul O Detwiler, New Concord, OH (US);
Barry M Mergenthaler, Cambridge, OH (US);
Wilbur I Hilles, Cambridge, OH (US);
Robert J Tom, Zanesville, OH (US);
NCR Corporation, Dayton, OH (US);
Abstract
The useful life of a laser, such as a laser diode, is extended by causing the laser to operate only intermittently when continuous operation is not required. When such a laser diode is used in a scanner for scanning coded symbols, such as bar codes, in merchandise check-out operations, continuous operation is required only when a coded symbol is present in a target area. A sensing device is provided for sensing the transitions in light reflected back from the target area, and a counter is provided for counting the number of such transitions. Since a much larger number of transitions are sensed and counted when a coded symbol is being read than when no such symbol is present in the target area, this difference in number of transitions is used to distinguish between the two conditions and to cause the laser diode to be turned on for continuous operation only when a coded symbol is present in the target area to be read.