| 摘要 |
PURPOSE: A device for pick-up enabling to detect a tilt of an optical disk is provided to easily detect the tilt by measuring asymmetry of sub-beams by detecting the shapes of the sub-beams, thereby reducing the cost and measuring the tilt regardless of a standard of the disk. CONSTITUTION: A device for pick-up enabling to detect a tilt of an optical disk includes a first phase plate(21) making a light emitted from a laser diode(11) in an optical system of an optical pick-up device pass through a collimation lens(12) and have phase difference of right and left, or up and down, so that the pick-up device detects the tilt by using right and left, or up and down asymmetry of a beam owing to the phase plate.
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