公开(公告)号：CA1232353A

公开(公告)日：1988-02-02

申请号：CA481599

申请日：1985-05-15

Applicant: IBM

Inventor： COHEN DONALD K ,  YARDY RAYMOND

IPC: G11C13/04 ,  G11B7/08 ,  G11B7/09 ,  G11B7/12 ,  G11B7/125 ,  G11B7/135 ,  G02B5/04 ,  G02B27/10 ,  G11B7/095

Abstract: An optical head for an optical signal recorder includes a nonpolarizing beam combiner for combining the light beams from two like-frequency, sic wavelength, lasers along one light path. The combined beams travel slightly diverging paths so that a first one of the beams can record signals on a disk while a second beam follows the first beam on the disk for direct reading-after-recording. Intermediate the combiner and the disk are a polarization type beam splitter and a focuser. One or more detectors receive reflected light from the disk via the beam splitter for detecting focus, sensed recorded signals and for tracking the beams to tracks or the disk. The combiner and splitter are preferably secured together as a single unit. The combiner uses refraction and internal reflection properties to combine the two like-frequency beams without polarization changes of either beam.