Abstract: A method of storing high resolution images on a videodisk in which signals associated with partial images are stored on successive disk tracks, the partial images making up the high resolution images. The partial images have a horizontal overlap of one point per line, which points are subsequently eliminated during the process of reconstructing the high resolution image. An encoder and decoder for effecting the above process is also disclosed.

Abstract: The invention provides a process for manufacturing optical disks by pressing and disks obtained by such a process, for improving the inherent flatness of the optical disk of the thick type, obtained by a process of pressing between a recorded master and another master, recorded or not depending on whether it is a question of a single or double side disk, this latter being formed from a stack of at least two thin sheets of thermoformable material subjected to a pressure-temperature cycle after which bonding together of the sheets and duplication of the information from the masters for information recording are obtained.

Abstract: An apparatus in which the video disk frames are reread while a shutter blocks the film in order to have during the rereading operation the time necessary for advancing the kinescope film without causing violent mechanical stresses. In order to pass from the television standard with 30 frames per second to the cinematographic standard of 24 frames per second, one frame out of five is not recorded on the film and the film advanced without any rereading.

Abstract: The present invention relates to methods for protecting against drop-outs in a sound signal recorded on a video-disc. It consists in recording onto a video-disc the same sound signal through the sub-carriers with a constant delay from one to the other. On reading out this video-disc, the two sub-carriers are restored to synchronism and the sub-carrier not altered is chosen for playing the sound signal.

Abstract: A method and apparatus for displaying a picture film via a video-disc which consists in analyzing the pictures of the film on a plurality of interlaced fields which are successively recorded onto a video-disc. These fields are then read simultaneously on this video-disc and the video signal thus obtained are used for modulating a display apparatus scanned according to a primary raster with a superimposed raster. A coding device is used for mixing the video signals and producing signals for synchronizing the display apparatus.

Abstract: A display device for producing polychromatic luminous images comprising a display panel containing gas cells, electrodes for ionization of the gas, and a photoconductive layer located between the electrodes and responsive to a scanning invisible radiating beam. Each cell further comprises luminophore emitting primary visible radiations at the time of ionization of the gas, the ionization being effected by rendering the photoconductive layer locally conductive.