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:
Nov. 03, 1998
Filed:
Dec. 18, 1995
Thomas W Karpen, Skaneateles, NY (US);
Dennis W McEnery, Marcellus, NY (US);
Robert C Gardiner, Liverpool, NY (US);
John A Pettinelli, Rome, NY (US);
Welch Allyn, Inc., Skaneateles Falls, NY (US);
Abstract
An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the time averaged value of the illumination level at the image sensor. A window detecting circuit periodically samples the illumination signal to determine if that signal is or is not within a window of acceptability. Exposure period determining circuitry uses the output of the window detecting circuit to upwardly or downwardly adjust the value of a control variable as necessary to cause the illumination signal to approach, enter and remain within the window of acceptability.