Image-type CGH by means of e-beam printing

Trial fabrication of image-type CGHs which are recorded by an electron beam printing system to display 3-D images is described. First, to verify the feasibility of fabricating CGHs for 3-D image reconstruction, two preliminary experiments, in which the divergence of the object wave was limited in one horizontal plane and the reference wave was defined as a plane wave from the horizontal direction, were performed. To confirm that the depth of reconstructed images can be perceived, two flat images (characters G and R) differing in depth and a simple wire frame object including some lines in the depth direction, were selected as object data. Both images were successfully reconstructed under the white light and thus the feasibility has been supported experimentally. Secondly, to reduce the blur caused by chromatic aberration and to improve the uniformity in luminous intensity in the reconstructed G-R image, the CGH was modified to image-type and the angle of divergence of the object wave was narrowed; thus the reconstructed image has been improved. Finally, to facilitate observation of the reconstructed image, the direction of the reference wave was modified to the vertical direction. All of the reconstructed images are shown and some technical problems are also mentioned.