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:
Jan. 18, 1994
Filed:
Jun. 25, 1993
Gregg A Marwin, Douglaston, NY (US);
Symbol Technologies, Inc., Bohemia, NY (US);
Abstract
In a bar code laser scanning system operable in a continuous scan mode and a sleep mode, an object sensing circuit for automatically switching said laser scanning system from the sleep mode to the scan mode is provided to help extend the operational lifetimes of the system components such as the laser diode and the scanning motors. When in the sleep mode, pulsed light is received and processed to generate a steady state voltage signal. Derived from the steady state voltage signal is a positive threshold voltage signal and a negative threshold voltage signal each having a magnitude respectively greater than and less than that of the steady state voltage level. The steady state, positive threshold and negative threshold voltage signals are input to a comparator means which detects when an object is placed in the scanning field of the laser scanning system. Object detection occurs when the steady state voltage increases above the positive threshold voltage signal or decreases below the negative threshold voltage signal depending upon the object's reflectivity. When an object is detected, a trigger signal is provided to direct the laser system to switch back into the scan mode without interrupting the normal scanning process.