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.
