LASER SCANNING SYSTEM EMPLOYING AN OPTICS MODULE CAPABLE OF FORMING A LASER BEAM HAVING AN EXTENDED DEPTH OF FOCUS (DOF) OVER THE LASER SCANNING FIELD

摘要

A laser scanning system having a laser scanning field, and a laser beam optics module with an optical axis and including: an aperture stop disposed after a laser source for shaping the laser beam to a predetermined beam diameter; a collimating lens for collimating the laser beam produced from the aperture stop; an apodization element having a first and second optical surfaces for extending the depth of focus of the laser beam from the collimating lens; and a negative bi-prism, disposed after the apodization element, along the optical axis, to transform the energy distribution of the laser beam and cause the laser beam to converge to substantially a single beam spot along the far-field portion of the laser scanning field, and extend the depth of focus of the laser beam along the far-field portion of the laser scanning field.

主权项

1. A system for reading symbols, comprising:
a scanning module for scanning a laser beam across a scanning field having a near-field portion and a far-field portion, the scanning module comprising:
a far-field source;a far-field optics module having an optical axis;a drive module for driving the far-field source and the far-field optics module to produce a far-field laser beam; anda scanning mechanism for scanning the far-field laser beam across the scanning field; a photo-detector for detecting the intensity of light reflected from the scanning field and generating a signal corresponding to the detected light intensity; a processor for decoding the generated signal to generate data representative of a symbol in the scanning field; wherein the far-field optics module comprises:
an aperture stop for shaping the far-field laser beam to a predetermined diameter;a collimating lens for collimating the far-field laser beam shaped by the aperture stop;an apodization element having a first optical surface and a second optical surface; anda negative bi-prism, after the apodization element along the optical axis, for transforming the energy distribution of the far-field laser beam to substantially a single beam spot in the far-field portion of the scanning field.