Mastering process for color graphic arts holograms

We have been developing holograms and holography technology for more than two decades for various applications. Embossed-type holograms manufactured by NDP are commercially available and are used widely in Japan. Currently, we are developing volume-type holograms. Some holographic optical elements (HOEs) and color graphic-arts are ready for commercialization. We are studying color holograms are ready for commercialization. We are studying color holograms as the next generation of volume-type holograms. At the previous SPIE meeting, we reported on the process for mass producing full-color Loppmann holograms and the adhesive film employed. This paper concerns the mastering process. It should be simple so as to be suitable for mass production, and a hologram copied from a master should have limited viewing range so as to provide greater brightness. To obtain a brighter hologram with the desired viewing angle, we employ a new modified Denishuku method for mastering. In this study, the relationship between the incident angles used for mastering and for copying was examined, and a new way of limiting the viewing area was devised. Through a combination of our mastering, replication and adhesive technologies, we have succeeded in mass production full- color holograms for the first time in the world. This has enabled DNP to develop commercial-level color graphic-arts holograms, some of which are widely available in the marketplace.