Abstract: The method of reading data from a data record carrier on which data has been recorded in arcuately nested, equal radii data rows which are equally spaced apart along a common centerline that is coextensive with a radius for each data row, comprises the steps of: incrementally moving the data record carrier in steps transversely of the data rows; projecting a light beam onto the plane in which the data record carrier moves; rotating the light beam about an axis parallel to the axis of said light beam to rotate said light beam in an arcuate path across the data record carrier, the radius of the arcuate path being the same or approximately the same radius of each data row; detecting scattered light outside the cone of specular reflection from the light beam impinging on the data record carrier, or the lack of scattered light, as the light beam traverses each data row; and sensing, and correcting for, difference between the arcuate path of said light beam and the arcuate path of the data row being traversed by sa

Abstract: An information record has a body of photographic film, paper, plastics material or the like, in which digital information is carried on a body in equal-radii, arcuate rows which extend across the body. The information may be stored as dark spots, light spots or dark-to-light or light-to-dark transitions with respect to transparent substances and in reflective areas, non-reflective areas or reflective-to-non-reflective or non-reflective-to-reflective transitions.

Abstract: A method for optically encoding digital data (12) on a substrate (11) without timing or synchronization data to form a data record carrier (10) includes the steps of: selecting a track (14) path on the substrate (11); selecting a data cell length (L) in the direction of the track (14) for each bit of data to be stored in each cell (15) on each track (14); selecting a cell width dimension (W) transverse to the direction of the track (14); selecting an optical non-transition cell (15) for one form of logic (0 or 1) to be stored in each such non-transition cell (15); selecting an optical transition cell (15) for the other form of logic (1 or 0) to be stored in each such other transition cell (15); creating at least one track (14) of digital data (12) on the substrate (11) comprised of a series of cells (15) each having the same cell length (L) in the direction of the track (14); establishing in each non-transition cell (15) on the substrate (11) a fully reflective or transmissive surface or a fully non-reflectiv

Abstract: The method for formatting optically encoded digital data on a planar substrate (11) without timing or synchronization data to form a data record carrier (10) includes the steps of: selecting an accuate track path on the substrate (11) for each one of a plurality of arcuate tracks (14, 14a, 14b) of data (12); selecting a data cell length (15) in the direction of each track (14) for each bit of data to be stored in each cell (15) on each track (14); selecting a cell width dimension transverse to the direction of the track (14); selecting a non-transition cell (A, C) for one form of logic (0 or 1) to be stored in each such cell (15); selecting a transition cell (B) for the other form of logic (1 or 0) to be stored in each such other cell (15); establishing a leader section (22) for each track (14); establishing a tailer section (24) for each track (14); establishing a front track address section (32) for each track; establishing a back track address section (44) for each track (14) and creating the tracks (14a a

Abstract: Data recorded in non-parallel arcuate paths on a data carrier are read with a laser beam which rotates relative to the data record.

Abstract: An optical floppy disc constructed of microfilm, thermoplastic or paper and bears digital and/or graphic information. Digital information may be stored in radial lines each of which comprises the digital information to be retrieved and line addresses at the end of a line or dispersed within a line. Digital information may also be stored in a plurality of coaxial circular tracks and be retrieved by addressing the track and portion of the track containing the desired information. Information retrieval systems, both continuously rotating and start-stop systems are provided for reading the various types of discs. Of particular importance is the use of a disc as an easily up-dateable catalog.