Servo control system for head recording and/or reproducing information on and/or from recording medium

A control system comprising:

• light gathering means for gathering light representing preselected information onto an optical disk;
• driving means for displacing said light gathering means relative to the optical disk;
• position detecting means for detecting a position of said driving means relative to the optical disk and providing a signal indicative thereof;
• signal processing means responsive to the signal from said position detecting means for controlling said driving means to displace said light gathering means to a desired position;
• deactivating means for deactivating an operation of said signal processing means when a value of the signal from said position detecting means falls within a preselected range;
• and
• parameter modifying means for modifying a preselected controlled parameter used in the operation of said signal processing means during a time when said deactivating means deactivates the operation of said signal processing means.

A control system comprising:

• light gathering means for gathering light representing preselected information onto an optical disk;
• driving means for moving said light gathering means relative to the optical disk;
• position detecting means for monitoring a position of said driving means relative to the optical disk at every constant cycle to provide a signal indicative thereof;
• converting means for converting the signal output from said position detecting means into a digital signal;
• signal processing means for processing the digital signal from said converting means;
• driving signal means responsive to a signal processed by said signal processing means to provide a driving signal for said driving means;
• comparing means for comparing a value of the digital signal converted by said converting means with a preselected value;
• deactivating means for deactivating an operation of said signal processing means according to a comparison result derived by said comparing means;
• and
• parameter modifying means for modifying a preselected controlled parameter used in the operation of said signal processing means during a time when said deactivating means deactivates the operation of said signal processing means.

A method for controlling a position of readout means for reading information out of a recording medium comprising the steps of:

• detecting a position of said readout means to provide a signal indicative thereof;
• processing the signal derived in said position detecting step according to a preselected operation when the detected position of said readout means is out of a predetermined range;
• moving said readout means according to a value of the signal processed in said signal processing step;
• deactivating an operation in said signal processing step when the detected position of said readout means falls within the predetermined range;
• and
• modifying a preselected controlled parameter used in the operation in said signal processing step when the operation in said signal processing step is deactivated in said deactivating step.