Abstract: A holographic recording of a plurality of rows of informational elements, which may represent a binary number, is successively illuminated by each of a plurality of light sources, where the number of light sources equals the number of rows of elements. In response to the successive illumination, a holographic reconstruction of the elements is projected upon photodetectors disposed along a line in a projection plane. The illumination may be instead by a deflected beam having an angle of incidence with the recording which changes at a vertical scan rate. In response to the deflected beam, a holographic reconstruction of horizontal lines of the elements are successively projected upon the photodetectors.

Abstract: A mask is used to sequentially illuminate successive elemental areas of an object (by changing the position of the mask) to obtain from each relatively small elemental area a diverging object-information component of coherent wave energy which is passed through a relatively large cross-sectional aperture of imaging and/or recording means. The fact that this cross-sectional aperture is so much larger in area than the area covered by any dust or optical defects of the imaging and/or recording means markedly reduces spurious coherent-wave patterns normally produced by such dust or optical defects. Further, since the illumination is not diffuse, no speckle pattern problem exists.

Abstract: The maintenance of a light spot of a chosen dimension on the surface of a rotating disc for optical playback or optical recording of data is effectively accomplished by a hydrostatic bearing apparatus. The apparatus includes: a housing for a lens assembly, which is disposed in the housing with its axis aligned parallel to the path of an incident light beam; a movable frame mounted on a support for movement in a direction substantially parallel to the light path; a pair of leaf springs coupling the housing to the frame for maintaining the axis of the lens assembly parallel to the light path; adjustable means for fixing an operating location for the movable frame; and a pressurized gas source coupled to a hydrostatic pad affixed to the lower portion of the housing, for providing a lubricating film of gas between the housing and the disc of a chosen thickness.