| 摘要 |
PURPOSE:To simplify the constitution and also to elevate the accuracy, by moving a divergent angle converting lens provided in the proximity of a condensing lens, in the direction meeting at right angles with the optical axis, and correcting a position of a condensing spot, and a relative speed. CONSTITUTION:A lens actuator 20 corrects a condensing spot shifted from an information track 15, by moving a collimating lens 9 in the direction meeting at right angles with not only the optical axis but also an information track 15. Tracking sensors 40a, 40b are provided on opposed positions where the information track 15 is placed between them, and an output of a tracking shift detecting circuit 42 is provided to the lens actuator. Also, a relative speed shift detecting signal is applied to the lens actuator 20 from a relative speed shift detecting circuit 41. |
