Each of right- and left-deflection holograms is provided for a picture element in a vertical scanning line on the screen of a display unit. For example, the right- and left-deflection hologram are alternately arranged in a single vertical scanning line. A normal image is displayed through the picture...http://www.google.fr/patents/US5926154?utm_source=gb-gplus-shareBrevet US5926154 - Double-screen display device
