ABSTRACT
A barcode scanner is an optical device that reads the code by scanning a focused beam of light, generally a laser beam, across the barcode and detecting the variations in reflected light. The most common barcode in the industrial environment is the so-called Bar Code 39, or 3 of 9 barcode. This code is fully alphanumeric and is self-checking. A number of technologies are available for deflecting the focused laser beam in a conventional, nonholographic, UPC scanner. The next development in the evolution of the scan pattern was the introduction of scan pattern wraparound. The use of holography in barcode scanning allows the introduction of scanning concepts that are not available to the designer of conventional barcode scanners, at least not in any economically practical design. The use of holography in a barcode scanner would allow the introduction of a true multifocal-plane scanner with a variable light-collection aperture.
