Patent ID: 6118747
Filing Date: 2000-09-12
Classification: G11B

Abstract:
A scanning device comprising:a turntable for rotating a disc-shaped recording medium about an axis of rotation;a radiation source; anda positioning device which is operable with respect to the turntable in a plane substantially transverse to said axis of rotation and which includes:an actuator unit having a base and a carrier which is moveable relative to the base and which carries several different objective lenses;a directing unit for directing a radiation beam emitted by the radiation source to one of the objective lenses; andtwo supporting bodies which are moveable relative to each other in a radial direction substantially transverse to said axis of rotation;characterized in that:the base of the actuator unit is secured to one of the supporting bodies and the directing unit is secured to the other of the supporting bodies;the objective lenses are disposed adjacent each another in said radial direction and have optical axes extending substantially parallel to said axis of rotation, each of said lenses being for focusing on an information plane of a respective one of several different types of recording media; andthe scanning device further compriseslatching means to latch the supporting bodies relative to each other in any of several different latching positions in which the directing unit is disposed opposite a respective one of the objective lenses to direct the radiation beam to that respective lens along the optical axis thereof; andactuating means for moving the two supporting bodies relative to each other between the latching positions, said actuating means including a first stop element disposed on one of the supporting bodies and a stationary second stop element, the first stop element being engageable with the second stop element during movement of the supporting bodies relative to each other from one latching position to another latching position,in which:one of the supporting bodies is in the form of a pivotal element which is pivotal about an axis parallel to said axis of rotation, and the second supporting body is supported with respect to the pivotal element and moveable relative thereto along a line extending substantially parallel to a perpendicular connecting line between the optical axes of the objective lenses.