Optical disc drive and method of controlling rotation speed of a spindle motor for rotating an optical disc

摘要

An optical disc drive has a spindle motor for rotating an optical disc; an optical pick-up which can move at least in a radial direction of the optical disc; a sensor for detecting the rotation of the motor; and a spindle servo for controlling the rotation number of the spindle motor based on signals from the sensor. This spindle servo is adapted to be operated at the time of changing the rotation number of the spindle motor, e.g. at the time of changing rotation speed of the spindle motor in multiple steps given by integral multiples of 1 or at the time of changing rotation speed when the optical pick-up moves in the radial direction of the optical disc. According to this optical disc drive, it takes a relatively short time until the rotation speed of the motor reaches the target rotation speed and its rotation becomes stable.