Abstract: The invention relates to a process for obtaining material of value from a bauxite residue which is obtainable or has been obtained by the Bayer process. This process comprises the steps of a) providing an aqueous suspension of the bauxite residue, b) setting a pH of the suspension to a value between 7.2 and 12.2, c) at least partly deagglomerating suspended mineral agglomerates of the bauxite residue, and d) separating the resulting mixture into an iron-rich fraction and into at least one further, preferably silicate-rich fraction. The invention further relates to an apparatus (10) for carrying out the process.

Abstract: The invention relates to a process for obtaining material of value from a bauxite residue which is obtainable or has been obtained by the Bayer process. This process comprises the steps of a) providing an aqueous suspension of the bauxite residue, b) setting a pH of the suspension to a value between 7.2 and 12.2, c) at least partly deagglomerating suspended mineral agglomerates of the bauxite residue, and d) separating the resulting mixture into an iron-rich fraction and into at least one further, preferably silicate-rich fraction. The invention further relates to an apparatus (10) for carrying out the process.

Abstract: The use of a holographic video screen which appears black, gray or colored in ambient light as the display surface in a vehicle, wherein a driver can view the screen while driving without taking his eyes of the road. Additionally, the display system containing such a video screen permits the projection and viewing of multiple images on a single screen.

Abstract: A display unit for an information processing system comprises a holographic image generating system. The information processing system may be a computer, television, telephone or other information system. The display may also be used in a large format, including a matrix of individual units, for sports arenas, road signs and the like.

Abstract: In an electronic image enhancement system, a reflex image is scanned in the interior of the eye. After modification by a processor, the image is projected back into the eye along the same path, and aligned in registration with the original scanned image. An elliptical scan pattern is used.

Abstract: A transparent holographic display screen for laser projection of at least one or more monochromatic wavelengths, is constructed to selectively diffuse an incident narrow-band laser beam at a predetermined solid angle and simultaneously to pass wide-band ambient light unobstructed through the display screen. The transparent holographic display screen has at least one holographic volume phase grating which is optically coupled to or integrated with a transparent carrier plate. The holographic display screen with its volume grating is produced by illuminating a real screen as an object into a primary hologram and recording a real holographic image of said real screen into a secondary hologram.

Abstract: The invention relates to a holographic display screen for laser projection of at least one or more laser wavelengths, which selectively diffuses the incident narrow-band laser beam at a predetermined solid angle and simultaneously lets the wide-band ambient light through unobstructed. Said display screen has at least one holographic phase grid which is optically coupled to a transparent backing plate. The invention also relates to methods for the production and the use of said device.

Abstract: An apparatus for recording the exterior retina reflex image of the human eye, has a scanning recorder. The beams of the exterior images pass through the spectacle glasses constructed on the inner side as vaulted, imaging, beam splitting mirrors. The scanning recorder for recording and detouring the parallel beam bundles exiting from the eye after backscattering by each spot on the retina, is a biaxial scanner. An opto-electronic detector receives the light bundles from the biaxial scanner for serial recording of the retina reflex image.

Abstract: A method and apparatus for transmitting light, wherein a holographic video screen is used as part of an illuminating system. The tendency of such a video screen to backscatter light of certain wavelengths from a predefined direction into a certain solid angle area is utilized to generate holographic images at precisely defined angles. In ambient light, such a video screen need not appear black, or at least dark.