| 摘要 |
PROBLEM TO BE SOLVED: To adjust response speed different by a variation in characteristics of a motor in moving an optical head at high speed. SOLUTION: This head feed mechanism for driving a driving motor 4 by a driving command obtained by adding a command with a signal subjected to positive feedback of current flowing through the driving motor 4 and carrying the optical head 2 into a target position, is provided with a means for measuring time constant of the driving motor 4. The mechanism has the function for increasing a feedback current amt. when a measured time constant is longer than a target and the function for decreasing the feedback current amt. when the measured time constant is shorter than the target. Consequently, a response characteristic of the optical head 2 can be controlled, then the response speed of the optical head 2 is not changed by the characteristics of the motor. Therefore, even when an optical pickup lens is driven independently of the optical head, the optical pickup lens hardly run out. |
