Laser scanning system using laser beam sources for producing long and short wavelengths in combination with beam-waist extending optics to extend the depth of field thereof while resolving high resolution bar code symbols having minimum code element widths

摘要

A laser scanning bar code symbol reading system having a scanning window, from which blue/red beam-waist-extended laser scanning planes are projected and intersect within an extended depth of field (DOF) defined adjacent the scanning window. In the illustrative embodiment, the laser scanning bar code symbol reading system includes a laser scanning subsystem having: a dual laser sources for producing a laser beams having blue and red spectral components; a collimating lens for collimating the laser beams; an aperture stop for shaping the cross-sectional dimensions of the collimated the laser beams; and beam-waist extending optics (e.g. axicon-lens) for extending the waist of the laser beam having a red characteristic wavelength.