OPTICAL SCANNING DEVICE WITH PARALLEL-CONTROLLED ACTUATORS

摘要

The invention relates to an optical scanning device (17) for use in an optical player. The scanning device comprises an optical lens system (37) for focusing a light beam (45) into a scanning spot (47) on an information carrier (9) to be scanned. The scanning device comprises a first actuator (51) by means of which the lens system can be displaced in a direction parallel to an optical axis (39) of the lens system for focusing the light beam on the information carrier. The first actuator is controlled by means of a first control unit (87) via a first control signal (uC1). The lens system comprises a main or objective lens (55) and an auxiliary or solid-immersion lens (54) providing the lens system with a large numerical aperture, so that the scanning device can suitably be used to scan information carriers with a high information density, such as high-density compact discs. The main lens is elastically suspended with respect to the auxiliary lens, and the lens system comprises a second actuator (63) for displacing the main lens with respect to the auxiliary lens in a direction parallel to the optical axis to compensate for a spherical aberration of the light beam in a transparent protection layer (13) of the information carrier. The second actuator is controlled by a second control unit (89) via a second control signal (uC2). According to the invention, the second actuator is also controlled by the first control unit via a third control signal (uC3) which is proportional to the first control signal. In this manner, resonances of the main lens occurring as a result of its elastic suspension are prevented.