Countertop projection laser scanning system for omnidirectional scanning

Abstract

A bar code scanner for stationary disposition at a counter to projecting a scanning pattern comprising first, second, third, fourth and fifth groups of parallel scan lines within a relatively narrow, yet diverging, volume, e.g., pyramid, cone, etc., centered about a projection axis. The scanner includes a compact housing mounted on an adjustible base. The housing includes a window, five stationary mirrors, a laser diode, a rotating reflective polygon for sweeping the laser beam from the diode across the mirrors and out a window so that the projection axis is substantially but not precisely perpendicular to the window. The scanner also includes a fixed curved collecting mirror and a concentrating lens to focus light which is reflected off of a bar code to a photodetector. One mirror extends along an axis parallel to the transverse axis to produce the first group of scan lines. The second and third mirrors are disposed opposite each other close to and laterally of the polygon and extending along respective axes at a small acute angle, e.g., 8 degrees, to the longitudinal axis to produce respective ones of the second and third group of scan lines. The fourth and fifth mirrors are disposed between the second and third reflecting mirrors, respectively, and each extends along a respective axis at a substantial acute angle, e.g., 48 degrees, to the longitudinal axis to produce respective ones of the fourth and fifth group of scan lines.