Barcode scanner having a dead zone reducing system and a multifocal length collector

摘要

An optical system for use in a scanning system for reading symbols. The scanning system includes a head for containing the optical system. The optical system comprises a light source for generating a beam of light. A scanner is provided for directing the beam of light towards the symbol and scanning the beam of light across the symbol. Further, in accordance with the present invention, a dead zone-reducing optical system is provided in the head for lengthening the optical path length between the light source and the scanner to reduce the length of the dead zone exterior of the head. A collector collects light reflected from the symbol and directs it to a detector. The collector includes at least two sectors each having different focal lengths. The detector detects the variable intensity of the returning portion of the reflected laser light over a field of view, and generates an electrical signal indicative of the detected variable light intensity.