A system of enlarging visual field and viewing zone simultaneously for electro-holography

It is difficult to realize a practical electro-holography, because visual field and viewing zone are limited, which are very narrow to see by both eyes. The problems are caused by the resolution of devices that display fringe pattern, such as on a SLM (acoustic optic modulator) and an AOM (acoustic optic modulator). A low resolution of device occurs ghost images that are high-order diffraction images of reconstructed images. Therefore the ghost images prevent large visual field and large viewing zone. We propose new configuration of electro-holography using LCD (liquid crystal display) that enlarges visual field and viewing zone simultaneously. The system consists of ail array of reconstruction lights, LCD, electro-shutter that is located between SLM and viewer. It is possible to prevent the rays from the ghost images by the shutter, to choose appropriate positions of both a reconstruction light in array and an aperture of electro-shutter. It shows viewers the original 3D objects without ghosts. Switching the combination of positions of reconstruction light and aperture of shutter for all fringe patterns synchronously is possible to see no-ghost images from any point of view. Furthermore, to switching very fast by time-division multiplexing, we can get large visual field and large viewing zone simultaneously. To verify the principle of the method, we made a system and carried out the experiments. In this paper, we discuss the method and the experimental results.