US Patent 7693017 Optical disc device

In a conventional method for preventing a collision between a lens and an optical disc which uses a control system similar to the servo control of the optical disc, it is feared that, when there is no need to apply the servo, the collision prevention method may not perform its function satisfactorily. In an optical disc device that operates with a part of its functions suspended for reduced power consumption, the conventional method is not enough to avoid the collision between the lens and the optical disc. By arranging the lens/disc collision prevention mechanism independently operable, it is possible to prevent the collision between the lens and the disc even during the operation with limited functions.