Abstract: An optical disc player/recorder includes a composite coil device for controlling both tracking and focusing functions of a moveable objective lens unit. A bobbin having orthogonal coils is supported by spring members and holds the objective lens. A magnetic gap field intersects both coils and current through each controls the focusing position and tracking position of the lens.

Abstract: An object (12) is moved by a motor (16) at a command speed which is a desired function of time. The current applied to the motor (16) is controlled in accordance with the phase difference between a periodic digital command speed signal and a periodic digital actual speed feedback signal. The two digital signals are applied in combination as an address input to a memory (67) which stores in the addresses thereof digital drive signals having magnitudes which are predetermined in accordance with the phase difference. The current applied to the motor (16) is proportional to the magnitude of the addressed drive signal.

Abstract: An angularly rotatable mirror apparatus including angularly rotatable mirror means and linear motor means. The angularly rotatable mirror means includes a mirror supported on a bracket and connected through an arm to the linear motor means for angularly rotating the mirror including a magnetic circuit consisting of a permanent magnet, a center pole an outer yoke, and a gap defined between the center pole and the outer yoke, and a movable coil arranged in the gap and connected to the arm. Means is provided for effecting control of the operation of the linear motor means in such a manner that a light flux reflected by the mirror will move at a constant speed on a surface to be scanned by the light flux.