Track access method and apparatus therefor

A track access method for a track access apparatus configured by an optical head, optical head drive motor means which drives the optical head, a focusing lens which is held via a resilient part to the main part of the optical head, lens actuator means which causes said focusing lens to be driven in the radial direction with respect to the direction of rotation of the recording medium, lens position error detecting means which optically detects the position error of the focusing lens with respect to the optical head in the recording medium radial direction, and control means which controls each of said means, whereby, in the case of moving said focusing lens is to be jump-moved to an immediately adjacent target track, when the movement of said focusing lens in the radial direction of said recording medium is being controlled by said lens actuator means in accordance with pre-established values of acceleration and deceleration, position control of said focusing lens so as to minimize said focusing lens position error with respect to said optical head in the radial direction of the recording medium is performed, beforehand, by driving said lens actuator means, compensation data obtained from a drive current of said lens actuator means being stored as the external force compensation value for said resilient part, said compensation data being obtained and stored before moving said focusing lens, said stored resilient part external force compensation value being added to the drive command value of said lens actuator means.

A track access apparatus comprising:

• an optical head;
• an optical head drive motor means which drives said optical head;
• a focusing lens which is held via a resilient part to the main part of said optical head;
• lens actuator means for causing said focusing lens to be driven in the radial direction with respect to the direction of rotation of the recording medium;
• lens position error detecting means for optically detecting the position error of said focusing lens with respect to the optical head in the recording medium radial direction;
• storage means for storing data;
• adding means for performing adding, and;
• control means which controls each of said means;
• wherein minimally when said focusing lens is moved to a target track, said control means performs position control of said optical head drive motor so as to make the position error of said focusing lens zero while performing control of said lens actuator means so that the speed of said focusing lens in the radial direction of said recording medium is in accordance with a pre-set reference speed which corresponds to the distance to said target track, and further wherein when position control is performed of said focusing lens so as to minimize said focusing lens position error with respect to said optical head in the radial direction recording medium beforehand, by driving the lens actuator means, stores compensation data obtained from the drive current value of said lens actuator means as the resilient part external force compensation value, said compensation data being obtained and stored before moving said focusing lens, adding means adding said stored resilient part external force compensation value to said lens actuator means drive command value when moving the focusing lens in accordance with said reference speed.

A track access apparatus comprising:

• an optical head;
• an optical head drive motor means which drives said optical head;
• a focusing lens which is held via a resilient part to the main part of said optical head;
• lens actuator means for causing said focusing lens to be driven in the radial direction with respect to the direction of rotation of the recording medium;
• lens position error detecting means for optically detecting the position error of said focusing lens with respect to the optical head in the recording medium radial direction;
• storage means for storing data;
• adding means for performing adding, and
• control means which controls each of said means;
• wherein minimally when said focusing lens is jump-moved to an immediately adjacent target track, said storage means stores, as external force compensation data for said resilient part, compensation data obtained from the drive current value of said lens actuator means when position control is performed for the purpose of reducing the lens position error of the focusing lens with respect to the optical head in the radial direction of said recording medium, said compensation data being obtained and stored before moving said focusing lens, and further wherein said adding means adds said stored external force compensation data to the drive command value of said lens actuator means when moving said focusing lens.