Abstract: The present invention is directed to a drive device comprising an electromechanical transducer (25) attached to one end of a drive shaft (24) and adapted to be expanded and contracted in the axial direction of the drive shaft (24) in accordance with drive voltage to thereby allow the drive shaft (24) to undergo displacement in the axial direction thereof, and an optical pick-up (14) movably supported in the axial direction of the drive shaft (24) and moved along the drive shaft (24) as the result of the fact that the drive shaft (24) is caused to undergo displacement by the electromechanical transducer (25) to apply a drive voltage higher than that at the time of steady transfer to the electromechanical transducer (25) at the time of starting.

Abstract: The range of air conversion optical path length L of all optical components in the forward passage of an optical system between a laser emission point and the surface of a disc-shaped recording medium is determined by: i(n0×d)+?L/2<L<(i+1)(n0×d)??L/2 (i is an arbitrary integer) where d is resonator length of a laser diode, n0 is active layer refractive index of the laser diode, and ?L is acceptable surface blurring in the specification of the disc-shaped recording medium, thereby reducing laser noise (optical feedback noise) that is generated when emitted laser beam from a laser diode is interfered with the optical feedback, which is a part of laser beam that has been focused on the recording surface of the disc and has moved back through the forward passage of the optical system to return to the laser diode.

Abstract: The present invention provides a recording and/or reproducing apparatus using a magneto-optical disc (3) as a recording medium, which includes a recording and/or reproducing mechanism (7) for recording and reproducing information signals to and from the magneto-optical disc (3) rotatably housed in a disc cartridge (2), a support base (19) which supports the recording and/or reproducing mechanism (7), and a impact drive mechanism (9) which causes the electromechanical-transduction element (25) to lengthen and shorten corresponding to driving pulses to shift the drive shaft (24) along the shaft direction thereof so as to cause the movable portion (27) to slide along the shaft direction of the drive shaft (24) together with the support base (19), and the recording and/or reproducing mechanism (7) and the impact drive mechanism (9) are arranged within a projection area of the openings (4a), (4b) of the disc cartridge (2) for exposing a part of the magneto-optical disc (3) to the outside from the inner to the oute

Abstract: The present invention is directed to a drive device comprising an electromechanical transducer (25) attached to one end of a drive shaft (24) and adapted to be expanded and contracted in the axial direction of the drive shaft (24) in accordance with drive voltage to thereby allow the drive shaft (24) to undergo displacement in the axial direction thereof, and an optical pick-up (14) movably supported in the axial direction of the drive shaft (24) and moved along the drive shaft (24) as the result of the fact that the drive shaft (24) is caused to undergo displacement by the electromechanical transducer (25) to apply a drive voltage higher than that at the time of steady transfer to the electromechanical transducer (25) at the time of starting.

Abstract: The present invention provides a recording and/or reproducing apparatus using a magneto-optical disc (3) as a recording medium, which includes a recording and/or reproducing mechanism (7) for recording and reproducing information signals to and from the magneto-optical disc (3) rotatably housed in a disc cartridge (2), a support base (19) which supports the recording and/or reproducing mechanism (7), and a impact drive mechanism (9) which causes the electromechanical-transduction element (25) to lengthen and shorten corresponding to driving pulses to shift the drive shaft (24) along the shaft direction thereof so as to cause the movable portion (27) to slide along the shaft direction of the drive shaft (24) together with the support base (19), and the recording and/or reproducing mechanism (7) and the impact drive mechanism (9) are arranged within a projection area of the openings (4a), (4b) of the disc cartridge (2) for exposing a part of the magneto-optical disc (3) to the outside from the inner to the oute