Turntable for optical disc player - has upper pressure plate forming part of magnetic circuit of motor

摘要

The optical disc player (1) has a turntable (11), an optical read head (15), control panel (7,9) and a hinged lid (21). Set in the middle of the hinged lid is a pressure assembly (5,23) which retains the disc in position while it rotates. The rotating pressure plate (23) does not rely on a spring to hold it in place on the top surface of the disc (19).4 The turntable (11) is rotated by an electric motor which has a central magnetic rotor (13). The pressure plate (23) in the lid is made from a piece of ferro-magnetic material which forms part of the magnetic circuit of the rotor. It is thus held in place, sandwiching the disc, by the rotor's magnetic field.