LASER FOCUSING APERTURE AND METHOD

摘要

Light is focused in a system for electro-optically scanning and reading bar code symbols by an aperture stop having a first optical portion (252) for optically modifying a first part of a light beam (262) to have a beam cross-section of a known size within a depth of field in which a symbol to be read is scanned by the first beam part, and a second light-transmissive, optical portion (254) bounding the first portion and operative for optically modifiying and directing a second part of the light beam (264) away from the first part.