Head positioner and information recording/replaying apparatus

A head positioner comprising:

• a coarse actuator and a fine actuator for performing positioning-control according to a dual-stage actuator method for a write/read head provided for accessing an information storage disk;
• and
• a positioning control unit for controlling the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

A head positioner having a configuration employing a dual-stage actuator method, wherein:

• positioning control is performed for a write/read head for accessing an information storage disk by using a coarse actuator and a fine actuator;
• the fine actuator is configured using a piezoelectric device;
• compensation is performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a disturbance exceeding a predetermined operation range of the fine actuator;
• and
• the level of a drive signal to be fed to the fine actuator using the piezoelectric device is set equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

A head positioner comprising:

• a coarse actuator and a fine actuator for performing positioning-control according to a dual-stage actuator method for a write/read head provided for accessing an information storage disk;
• and
• a positioning control unit for controlling the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises
• a position-error separating unit for separating compensation so as to be performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a disturbance exceeding a predetermined operation range of the fine actuator;
• and
• a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

A head positioner having a configuration employing a dual-stage actuator method, wherein:

• positioning control is performed for a write/read head for accessing an information storage disk by using a coarse actuator and a fine actuator;
• the fine actuator is configured using a piezoelectric device;
• compensation is performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a rotational synchronization disturbance of the disk;
• and
• the level of a drive signal to be fed to the fine actuator using the piezoelectric device is set equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

A head positioner comprising:

• a coarse actuator and a fine actuator for performing positioning-control according to a dual-stage actuator method for a write/read head provided for accessing an information storage disk;
• and
• a positioning control unit for controlling the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises
• a disturbance compensating unit for performing compensation in the coarse control system for a positional deviation of the head that occurs from a desired track because of a rotational synchronization disturbance of the disk;
• and
• a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

A head positioner comprising:

• a plurality of write/read heads for individually accessing a plurality of concentric information storage disks;
• a plurality of fine actuators for finely displacing the individual heads;
• a plurality of head supporting mechanisms for supporting the individual fine actuators;
• and
• a coarse actuator for driving the plurality of head supporting mechanisms in batches, wherein:
• according to a head position signal read out by each of the head from each of the disks, control is performed for each of the fine actuators so that the corresponding head follows a desired track;
• and
• a median value is selected from relative displacement values of the individual fine actuators, and control is performed for the coarse actuator according to the selected median value.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head, for,accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• and
• the level of a drive signal to be fed to the fine actuator using the piezoelectric device is set equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head for accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head for accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting, mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• compensation is performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a disturbance exceeding a predetermined operation range of the fine actuator;
• and
• the level of a drive signal to be fed to the fine actuator using the piezoelectric device is set equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head for accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises
• a position-error separating unit for separating compensation so as to be performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a disturbance exceeding a predetermined operation range of the fine actuator;
• and
• a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head for accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• compensation is performed through operation of the coarse actuator for a positional deviation of the head that occurs from a desired track because of a rotational synchronization disturbance of the disk;
• and
• the level of a drive signal to be fed to the fine actuator using the piezoelectric device is set equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.

An information recording/replaying apparatus comprising:

• a rotatable information storage disk;
• a write/read head for accessing the disk;
• a fine actuator for finely displacing the head;
• a head supporting mechanism for supporting the fine actuator;
• a coarse actuator for driving the head supporting mechanism;
• and
• a positioning control unit for performing positioning control for the write/read head according to a dual-stage actuator method using the coarse actuator and the fine actuator, wherein:
• the fine actuator is configured using a piezoelectric device;
• the positioning control unit comprises
• a coarse control system comprising a coarse drive unit for driving at least the coarse actuator and coarse control unit for controlling the coarse drive unit, and
• a fine control system comprising a fine drive unit for driving the fine actuator and a fine control unit for controlling the fine drive unit;
• and
• the head positioner further comprises
• a disturbance compensating unit for performing compensation in the coarse control system for a positional deviation of the head that occurs from a desired track because of a rotational synchronization disturbance of the disk;
• and
• a driving-signal limiting unit for limiting the level of a fine control signal fed from the fine control unit to the fine drive unit to be equal to or lower than a threshold at which property deterioration of the piezoelectric device is caused by an electrochemical reaction.