Separation type mono block optical head with tracking control achieved

Abstract

A device for accessing and following tracks on a surface of mobile media on which data is optically readable and writable by a laser beam. The device includes at least one optical head made of a rigid carriage which enables a laser beam (F) to access the track. A lens is rigidly linked to the rigid carriage (3) and focuses the laser beam on the surface of the mobile data medium. A return mirror is rigidly linked to the rigid carriage to direct the laser beam towards the lens. At least one motor coil allows movements of the carriage to focus the laser beam. A mirror which is not fixed to the optical head allows the laser beam to be directed towards the optical head, and a motor coil allows the mirror to pivot. Also means are provided for detecting and correcting any decentering of the beam in relation to the axis perpendicular to the plane of a pupil of the lens and passing through its center. The correction is applied along a direction defined by the axis, perpendicular to said axis and contained in the plane perpendicular to the plane of the pupil, and the center of the return mirror, and the center of the mirror which allows the laser beam to be directed towards the optical head. The device is applicable to readers and recorders of mobile media containing optically readable or recordable data.