ABERRATION CORRECTIONS FOR A POS HOLOGRAM SCANNER

Use of an optically generated IZP (interferometric zone plate) hologram scanner enables highly accurate reading in a supermarket point-of-sale (POS) label reader with a simple optical arrangement. The laser beam spots on the scanning plane which construct the lattice scan pattern designed for the POS label reader cause severe aberrations when a conventional IZP hologram is used. A simple and effective method for removing the aberration is discussed from both the theoretical and experimental aspects, and the feasibility of the method is demonstrated. This method employs oblique-angle coherent plane-wave illumination in the IZP hologram recording process. © 1979 Optical Society of America.