| 摘要 |
PURPOSE:To provide the optical recording information reproducing device hardly affected by a recording layer which is not addressed at the time of reproducing of the optical multilayered recording medium. CONSTITUTION:Two pieces of laser beams having a 180 deg. phase difference from a light source section A are imaged by a lens 4a on the optical recording medium 5. Two pieces of the laser beams past the optical recording medium 5 are multiplexed by an optical coupler 2b and is supplied to a photodetector 6. Two pieces of the laser beams to this photodetector 6 have antiphases in the non- recording parts of the optical recording medium 5 and the output is not generated but the antiphases are eliminated and the output is generated by a difference in refractive index, etc., in the recording parts. |
