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US 4,124,268 AGranted
Optical device for the storage and the selective erasure of information
AssigneeThomson-CSF
InventorsFrancois Micheron, Jean Pierre Huignard
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Abstract
The object of the invention is to provide a device for storing and selectively erasing information in electrooptical photoconductive materials in which selective recording and erasure are obtained by identical optical devices which project the same distribution of light onto the zone to be recorded and then erased. Recording and erasure differ solely in the direction of the electrical field applied to the material.
Claims4
An optical device for the storage and the selective erasure of information comprising:
- a photoconductive electro-optical storage material, said material having a symmetrical electrooptical characteristic;
- optical means which, for the storage, ensure the photoexcitation of a zone of said material by a network of interference fringes, said photoexcitation photoinducing an elementary hologram in said zone for the read-out of said elementary hologram, provide the illumination of said zone by a beam of monochromatic light and for the selective erasure of said elementary hologram, ensure the photo-excitation of said zone by the same network;
- and
- polarizing means for applying a first electrical field within said material during said storage and a second electrical field during said erasure of the same zone, said second electrical field being opposite to said first electrical field, said fields being orthogonal to said interference fringes.
1 more element
Dependencies are inferred from the claim text.