APPAREIL HOLOGRAPHIQUE POUR L'ENREGISTREMENT ET LA REPRODUCTIONDU SON

摘要

1378860 Holography R C A CORPORATION 3 Dec 1971 [14 Dec 1970] 56202/71 Heading G2J A hologram 13a of a sound track 11a is formed from the image of the sound-track which image has been reduced in size relative to the appopriate sound-track portion by a lens 25 between the image plane and the sound-track. The hologram is a Fresnel hologram and is thus capable of being read-out continuously. The frame size selected, to which the image size is fitted to avoid either overlap or gaps between successive such holograms is that of Framhofer holograms of video information. In a second embodiment, Fig. 5 the video and sound tracks 31a, 31b tone respectively illuminated through two uni-directional phase-gratings 30, 32 respectively, the sound information beam being directed by a prism 33 before being reduced in size by optics 34, 35.