| 摘要 |
An optical data record playback apparatus is described for simultaneously scanning a plurality of data tracks on the optical record by employing two or more light beams controlled by closed loop servos. First and second optical servo means respectively, are employed to deflect the light beams for tracking of such beams during scanning along the data tracks and for maintaining the proper spacing between beams to cause each beam to follow a different track. In addition, a time adjust means, which may be a third optical servo or an electronic signal delay means, is employed to adjust the time relationship of the two readout signals produced by such light beams. The optical servos may include either movable mirrors or light refraction plates. Alternatively, an electromagnetically deflected bundle of optical fibers can be employed as the first servo and a zoom lens at the output of such fibers as the second servo. Also, a double refraction polarizing device, such as a calcite crystal, can be employed as both the second and third servos by pivoting such crystal about two mutually perpendicular axes.
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