Patent ID: 8014249

Claim:
A method for operating an optical drive system capable of reproducing/recording information from/to an optical carrier, wherein the optical drive system comprises: a radiation source for generating a radiation beam, a focusing means for focussing the radiation beam, an optical receiver means for generating an electric read signal in response to radiation reflected from the optical carrier, a focus tracking system for tracking the carrier with said focussed radiation beam, wherein said focus tracking system comprises a focus error generating means for generating a focus error signal, a focus actuator means for changing a focus position of said focussed radiation beam relative to the optical carrier, said focus actuator means being driven by a supplied correction signal, and a correction signal generating means comprising a focus controller means for controlling said focus actuator, and, said focus controller means being supplied with said focus error signal, and a focus memory loop for applying a stored correction signal to said focus actuator, the method comprises the steps of: a) determine if an event has occurred that requires at least a gradual stop of said focus tracking system, and if positive then, b) disable the focus controller means by opening the control loop, and c) gradually reducing, over a period of time, at least one of: a memory loop parameter of said focus memory loop, said parameter corresponding to an amplitude of said stored correction signal, and a controller parameter of an integrating means of said focus controller means, said controller parameter corresponding to a focus offset position, wherein the period of time is determined based on a natural frequency of the focus actuator means.