FOCAL POINT POSITION CONTROL DEVICE, OPTICAL DISC DEVICE USING THE SAME, AND FOCAL POINT POSITION CONTROL METHOD

摘要

A focal point position control device includes: a storage means (76) which synchronizes a control signal for controlling the optical beam focal point position to be a desired position, with a clock signal and successively stores the control signal as storage data in a clock address looping back at one rotation of the optical disc; a storage data output means (77) which successively reads out the storage data stored in the storage means (76) in synchronization with the clock signal; a phase correction means (78) which corrects the phase of the clock address associated with the storage and the clock address associated with the read-out when the storage data output means (77) reads out the storage data from the storage means (76); and an addition means (72) which adds the output signal from the storage data output means (77) to the control signal.