Abstract: An apparatus and method is presented wherein the lens system or assembly is fixed in its location along an optical axis between an object and its image. The focusing of the object, which may vary its position along the optical axis, occurs through adjusting a detection medium or an imager to the position in image space where the image space is focused on its image plane. The invention is structured to facilitate this focusing in an automatic and very rapid manner to accommodate rapid changes in the location of the object along the optical axis.

Abstract: An improved bar code scanning and reading apparatus which is adapted to be hand-held utilizes anamorphic optics for scanning and reading the code by providing a beam having an oblong cross-section in the nominal plane of the code. The oblong cross-section may be aligned with the bars of the code. The optics does not focus the beam in the longitudinal direction of the cross-section at the nominal plane of the code so that diffraction effects which would otherwise cause rotation of the cross-section of the beam to a position transverse to the bars of the code which would preclude reading of narrow bars, is avoided. The last lens of the anamorphic system may be a cylindrical lens which provides a line focus of a visible marker beam while at the same time providing the oblong cross-section of the beam which scans the code. The light from the vicinity of the code passes through the cylindrical lens and is collected by a toric reflector which projects the incoming light onto a photodetector.