Incoherent-coherent optical transducer for holographic data storage - has facility to recognise characters using hologram

摘要

The optical transducer contains a cathode-ray tube (3), a fluid-crystal photoconductor layer structure (2), a coherent light source and one or more image-forming lenses (8). The fluid-crystal photoconductor layer structure is positioned in direct proximity to the cathode-ray tube and a coherent light beam (1) strikes the layer structure. This layer structure can be connected fast to the cathode-ray tube. A recording medium (7) is used to record holograms and there is a reference beam (6). Control electronics (4) are used to produce on the screen of the cathode-ray tube the image to be recorded and which is projected on the rear of the layer structure.