Tomoko Kumasawa

Quality evaluation of Lippmann-type hologram using CGH

Dai Nippon Printing Co., Ltd. (DNP, Tokyo, Japan) has succeeded in recording Lippmann holograms with an image of Computer-Generated Holograms (CGHs). As Lippmann holograms are usually made by real three-dimensional object, design variation of the objects are restricted by the possibility of manufacturing the object. On the other hand, as CGHs are made by computer graphics (CG), many different kinds of virtual images can be built into holographic images. Also, it has very fine resolution because it is made by the Electron-Beam lithography system. By incorporating the image expression of the CGH into Lippmann hologram, we have developed a new hologram combining both CGHs and the Lippmann holograms.

Quality evaluation of full color hologram

The quality of a hologram depends on many factors including its resolution, brightness and color reproduction. In a holographic image, good resolution entails that overt and covert images are clearly visible. However, the effects of using the H1H2 method to construct holograms, on the resolution of holographic images have not been investigated to date. In this study, the resolution of images reconstructed from mass-produced color Lippmann holograms using the H1H2 method was evaluated. Silver halide (H1, master hologram) and photopolymer (H2, intermediate and H3 mass-produced holograms) were used as recording materials. Results indicated that the resolution of H3 images decreased progressively as noise in H1 images increased. The noise in H1 images was dependent on conditions related to developing the silver halide and factors related to producing H1. Optimizing the process of creating H1 images was effective in creating high quality H1H2 holograms.

Color evaluation of full color hologram

This paper concerns the new full color mastering process in order to obtain full color three-dimensional Lippmann holograms with flipping effect. As holographic recording materials, both newly developed red-sensitized silver halide P7000 and photopolymer were appropriated. In this study, the color reproduction and the viewable zone in vertical and horizontal directions of resulting full color Lippmann holograms were examined. The angle dependence of the reproduced colors of the holograms with both the new H1H2 mastering method and the previously reported modified Denisyuk mastering method were evaluated. The holograms using the new method showed better color reproduction and were brighter than the holograms using the modified Denisyuk method. To combine above mastering technology with mass-production technology and layer structure technology, we have succeeded in the mass-production of full color holograms with flipping effect.

The recent holographic material: Konica P7000

A newly developed silver halide material, KONIKA MINOLTA OPTO P7000, was examined its holographic characteristics. The commercially available material, KONIKA P5600, is blue-green sensitive but the new P7000 shows enough sensitivity to red light for practical use. We recorded holograms with He-Ne laser light on P7000 plates and evaluated the holographic characteristics such as diffraction efficiency and reconstructed wavelength. The results are discussed comparing with those of former Agfa products.