Apparatus for projecting a light beam onto an optically readable record carrier.

摘要

An apparatus for playing optical discs is described, in which for a smoother locking-in of the focus servo control the focusing error signal is initially derived from the amplitude of the h.f. signal, followed by a gradual change-over to a difference signal derived by means of subdetectors. In this way the focus control point with the servo loop closed is shifted towards the desired in-focus point.