| 摘要 |
PURPOSE:To simplify the position adjustment of an optical axis by executing the optical transmission between a 1st optical system including a light source and a photodetecting means and a 2nd optical system including an objective laser and actuator via an optical fiber. CONSTITUTION:A reflected light ray R1 positioned at the left end of the reflected ray flux of a recording medium 20 and the reflected ray R2 positioned at the right end cross in the optical fiber 16 and are again crossed and reflected by a beam splitter 13. These rays are introduced through a lens 14 to a photodetector 15 while the rays are respectively positioned at the left end and right end of the reflected ray flux. The change in the intensity of the reflected light of this progress recording medium 20 is transmitted as it is to the photodetector 15 via the end face 16B and end face 16A without being restricted to the disposition shape at the intermediate point of the optical fiber 16 during this course and is read out as an RF signal. The restriction of the relation of the disposing position to which the 1st optical system 12 and the 2nd optical system 17 are subjected with each other is, therefore, decreased. The position adjustment of the optical axis is simplified in this way. |
