Abstract: An optical scanner for reading indicia of variable light reflectivity, such as bar code symbols, having a light source for producing a light beam for scanning a target; a sensor for collecting the reflected light from the target; and various light collection systems, including a louver formed from an array of thin slats positioned adjacent to the sensor so that light directed along substantially only one angle reaches the sensor, as well as imaging/diffusing optical systems.

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.

Abstract: A drive circuit excites a stepper motor. A current steering network alternately conducts current through first one and then the other of a set of AC windings. A regulated current source excites the DC windings of the stepper motor such that magnitude of the resultant vector due to the current in the motor is substantially constant in time.