Methods of and systems for illuminating objects using planar
laser illumination beams having substantially-planar
spatial distribution characteristics that extend through the
field of view (FOV) of
image formation and detection modules employed in such systems. Each planar
laser illumination beam is produced from a planar
laser illumination beam array (PLIA) comprising an plurality of planar
laser illumination modules (PLIMs). Each PLIM comprises a
visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar
laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar
laser illumination beam having substantially uniform
power density characteristics over the entire spatial extend thereof and thus the
working range of the
system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum
object distance at which the
system is designed to acquire images, thereby compensating for decreases in the
power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging
optics. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type scanning applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.