OPTICAL DISK TILT COMPENSATION DEVICE, OPTICAL DISK RECORDER, OPTICAL DISK REPRODUCING DEVICE, AND OPTICAL DISK RECORDING AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To cope with the problems that increase of NA of an objective lens (called as OL, hereafter) is performed while shortening of wavelength of reading and writing light is performed; a tilt margin of the optical disk decreases when the NA is increased, control and compensation of a pickup, etc. become necessary; highly precise tilt servo system is indispensable for attaining higher density; there is a problem in a detection error in the conventional tilt sensor; drive of 40Hz of a reference wave component to hundreds of Hz of a harmonic component becomes necessary and light tilt of the OL is necessary in a large capacity optical disk.;SOLUTION: A disk tilt signal is generated by inputting a focal actuator control signal Fo for transferring the OL in the focal direction and linear velocity V in a disk tilt signal generator. The tilt which changes in one rotation of an optical disk is compensated by taking difference between the disk tilt signal and an OL tilt signal from an OL tilt sensor, generating a relative tilt signal between the optical disk and the OL and inputting the relative tilt signal in a compensator.;COPYRIGHT: (C)2006,JPO&NCIPI