Optical disc access control apparatus

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an optical disc recording and/or reproducing apparatus according to the present invention is explained by referring to the drawings.
The optical disc recording and/or reproducing apparatus of the present invention is constructed as shown for example in FIG.
2.
With the apparatus shown in FIG.
2, the present invention is applied to an optical video disc player in which an optical video disc 3 is detachably mounted by chucking magnet 4 onto a disc table 2 which is rotationally driven by a spindle motor 1 at a constant linear velocity for detecting and reproducing signals recorded on the optical video disc 3 by an optical pickup 5.
Meanwhile, the optical video disc 3 is a 30 cm video disc operating under the CLV system.
The spindle motor 1 is rotationally rotated at an rpm of 600 to 1,800, that is at a rotational frequency of 10 Hz to 1,800 Hz, by a spindle servo circuit 7, controlled by a system controller 6, depending on the position of a track on the optical video disc 3 scanned by the optical pickup 5 so that the linear velocity of the optical video disc 3 will be constant.
The optical pickup 6 is mounted on a feed block 11 threadedly engaged with a lead screw 10 rotated by a translating motor 9, and is adapted to be moved along the radius direction of the optical video disc 3 by the movement of the pickup block 11 brought about by the rotation of the lead screw 10.
Meanwhile, the driving control of the translating motor 9 that is translation control of the optical pickup 6, is achieved by controlling a motor driving circuit 12 driving the translating motor 9 by the system controller 8.
The optical pickup 5 has its objective lens moved in the focusing controlling direction and in the tracking controlling direction by a so-called biaxial actuator so that focusing servo and tracking control will be applied by a focusing and tracking servo circuit 13 operationally controlled by the system controller 6.
It is noted that the optical pickup 5 has tracking transmission characteristics such that a resonance frequency f