Erasable thermo-optic storage display of a transmitted color image

摘要

The invention provides an optical display device, utilizing a thermo-optical effect to inscribe a transmitted image in a layer of a material exhibiting a smectic state. Recording of the image with a full range of half tones without modulation of the recording beam and quick erasure of the recorded image without reheating of the film can be obtained by directly applying, simultaneously to the whole of the film either the video signal or an erasure voltage of suitable values. By associating this display device to a projection device utilizing a very bright source, the image thus recorded can be projected onto a large screen or a photosensitive substrate. The invention also describes a color images teleprojection and telereproduction device, in which three distinct chrominance images are recorded in a smectic layer as above described and simultaneously illuminated with white light; the three beams thus obtained are filtered for respectively selecting in each of them the spectral band corresponding to the chrominance of the image and superimposed in a single beam by a reflecting system. An objective lens supplied with a diaphragm in its image focal plane receives this single beam and projects the reconstituted colour image onto a screen or a photo-sensitive layer.