| 摘要 |
PURPOSE:To apply the relative position control by the 1st and 2nd drivers by providing an equivalent circuit of the driver to a control circuit having both the drivers for coarse position control and fine position control and using an output of the equivalent circuit and a position control signal to drive the 1st driver. CONSTITUTION:A control signal X1''' based on an input (terminal 19) of a position error signal Y1 is fed back to subtract (1) from the next error signal Y2, the resulting signal M is subject to phase compensation 2 and the result is fed to an objective lens driver 4 and its equivalent circuit 11. On the other hand, a positive control high frequency component of an HPF 17 is extracted and added (18) to the signal M1 to control a phase compensation 3 and a linear motor 5, the relative displacement between the head and the objective lens is detected to apply the relative position control attended with the movement of drivers 4, 5. Further, the signal M1 is fed to an equivalent circuit 14 of a crosstalk 13 between the drivers 4, 5 and to the equivalent circuit 12 of the driver 5, outputs of the circuits 14, 11 is added (15), the output of the circuit 12 is subtracted (16) and inputted to an LPF 17 thereby correcting a position control error attended with the relative movement between the drivers 4 and 5. Control signals X2''' and X2' are used to apply position control with high speed and high accuracy. |
