Bar code reader including a pre-raster oscillator mirror

Abstract

A bar code reader of the type which directs a light beam to scan an area (i.e. raster scan) is disclosed herein. The reader includes first and second oscillating mirrors for directing a light beam from a photodiode to a bar code, and for directing portions of the light beam reflected from the bar code back to a photodetector which generates an electrical signal representative of the information embodied in the bar code. The first oscillating mirror scans the light parallel to a first line (e.g. vertical line) at a first frequency onto the second oscillating mirror. The second oscillating mirror scans the light from the first mirror parallel to a second line (e.g. horizontal line perpendicular to the vertical line) at a second frequency greater than the first frequency onto the bar code. The first mirror may be a compound mirror having a concave, reflective surface which circumscribes a flat, reflective surface. The concave, reflective surface increases the amount of light reflected by the bar code which is reflected back to the photodetector via the first and second oscillating mirrors.