Optical data storage and retrieval apparatus

Abstract

An optical data storage system includes automatic compensation for shifting movements of the reading/writing beam and other imperfections which otherwise would affect the focusing or location of focus of a laser light beam onto a data storage record. Servo motors and associated apparatus common in the prior art are avoided. The recording or reading laser beam is directed as parallel light toward the data recording medium, but is first focused generally to a line by a first cylindrical lens supported by the laser source apparatus and transverse with respect to the orientation of data tracks of the data storage record. This produces a beam which is parallel in one direction as it approaches the data storage record. The beam is then focused substantially to a point by a second cylindrical lens perpendicular to the first lens and attached to and moveable with the data storage record as an integral part of a disk or card or other data storage structure. A series of such second cylindrical lenses are positioned side-by-side, with parallel longitudinal axes, on the data storage record. In this way, transverse relative movement of the laser beam with respect to the data tracks and the data record lenses and changes in the separation distance between the laser source and the data storage record, will not result in substantial defocusing or of a shift in the location of the beam focus point on the data record.