Photorefractive read-only optical memory apparatus using phase, frequency, and angular modulation - 6026053

The present invention stores and retrieves digital information by altering the phase transmission characteristics of a multiple layer phase recording by modulating the carrier frequency and the carrier frequency angle. These layers are organized into several regions, called page areas, which contain an array of juxtaposed encoded digital information data. Each page area may have several pages of digital information; each recorded with a different carrier frequency and carrier angle. The data layers are stacked together and aligned such that the page areas and encoded digital information on them are also aligned with each other into books. When one of these books is selectively illuminated by a controllable light source, a lenslet aligned with that book projects the transformed images of the data pages within that book, through a shutter array, and a reimaging lens onto a photosensor detector array. By selectively illuminating individual books and selectively opening the transform plane shutter to pass a single desired transformed page of digital data, any desired page of any desired book in the stack of data layers can be imaged onto the photosensor detector array. Pages of data can thus be randomly accessed and all data on that page can be read in parallel at speeds limited only by the access speeds of the illumination source, spatial frequency plane shutter array, and photosensor detector array.Photorefractive read-only optical memory apparatus using phase, frequency, and angular modulation602605315/02/200021/05/19992000270Satorius; Duane A.US Patent and Trademark OfficeGoogle Patent detector arrayencoded digital informationbookspagepage areasdata layersplane shutter arrayphase transmission characteristicsspatial frequency planepresent invention stores