Floating image display with a fine pixel pitchcomputer-generated hologram

Hiroshi YoshikawaTakeshi YamaguchiTomohisa ItoHiroyuki OzawaNihon UniversityCollege of Science and TechnologyDepartment of Electronics and Computer Science7-24-1 Narashinodai, Funabashi-shiChiba 2748501, JapanE-mail: yamaguchi@ecs.cst.nihon-u.ac.jpAbstract. The floating 3-D image, when utilized as a 3-D display, gives astrong dimensional impression to the viewer. Few researches, however,have been conducted on the floating image display by means of the com-puter-generated hologram (CGH). Since the required pixel pitch is narrowcompared with the non-floating image display, the CGH that displays thefloating image could hardly be output. If the CGH is output by the devicewith insufficient pixel pitch, the viewing area and image size of the CGHare not suitable for practical use. Therefore, the object is usually placedbehind the hologram to relax the pixel pitch. Reducing the time in calcula-tion is also required. The authors have been developing the fringe printer,the device for fringe patterns, which can be reproduce holograms with thepixel pitch as fine as 0.44 μm. This study investigates the fabrication thefloating image display, which is output by the fringe printer, with widerviewing angle and larger image size. It is clear that the image is neces-sarily reconstructed by the conjugate of the original reference wave toreproduce the real image.