Patent ID: 6122234
Filing Date: 2000-09-19
Classification: G11B

Abstract:
An information storage apparatus using a synchronous motor to rotate an information storage disk at a constant linear velocity relative to a pickup head during reading the pickup head moving radially across the storage disk, the apparatus comprising:a rotatable information storage disk;a pickup head for reading and seeking information on said disk;a synchronous motor for rotating said storage disk at a variable rotational speed to achieve a constant linear velocity relative to said pickup head during reading;a pickup head moving mechanism for moving said pickup head radially between an inner periphery and an outer periphery of said disk, said mechanism moving said pickup head quickly during seeking to minimize a seeking time;a pickup head operation detector for generating (1) a speed signal when said pickup head moves quickly during seeking, (2) an acceleration direction signal when said pickup head moves from the outer periphery to the inner periphery of said disk during seeking, and (3) a deceleration direction signal when said pickup head moves from the inner periphery to the outer periphery of said disk during seeking; anda motor controlling circuit for applying to said motor a plurality of electrical excitation patterns, said circuit applying (1) a first electrical excitation pattern, which achieves the variable rotational speed and constant linear velocity of said storage disk relative to said pickup head, during reading, (2) a second electrical excitation pattern, which accelerates the variable rotational speed of said disk, upon receiving the speed signal and the acceleration direction signal from said pickup head operation detector and (3) a third electrical excitation, which decelerates the variable rotational speed of said disk, upon receiving the speed signal and the deceleration direction signal from said pickup head operation detector.