Recent developments in holographic scanning

Abstract

Holographic scanning has been used in bar code readers since 1980. The technology has evolved since that time to include industrial bar code scanners as well as the more familiar supermarket scanners. During this evolution, a number of innovations have allowed the capabilities of the technology to be more fully exploited. This paper will review the technical developments made at IBM over the last ten years, with emphasis on the application requirements that motivated the developments. The major developments to be discussed include: multiple focal-plane scanning, retro-collection, variable facet width, scan-angle multiplication, overlapping focal-zones, complex facet shapes, facet identification, and raster scanning. Some recent developments in holographic disk fabrication will also be discussed. These new developments have allowed the construction of complex facet shapes and offer the potential for significant reduction in disk manufacturing costs. © 1989 SPIE.