Optical system for a large depth-of-field bar code scanner

摘要

An optical system for a bar code scanner has a working range (27,57,67) that is not determined by the lens aperture, but by the dimension and orientation of the detector (27,55). In the preferred embodiment, the desired working range (27,57,67) is imaged onto a detector array (25,51) using a modified Scheimpflug arrangement. The array (25,55) in the first Scheimpflug plane (B) with respect to the lens (21,41,61) defines a second Scheimpflug plane (C) that intersects the bar code tag (23,43,53) to be read. So long as the bar code tag (23,43,53) intersects the image (25a) of the detector array in (25,55) the second Scheimpflug plane (C) a portion of the image (23a) of the bar code tag (23,43,53) will be in focus on at least one of the elements of the detector array (25,55).