Signal pickup device in a rotary recording medium reproducing apparatus

Abstract

A signal pickup device comprises a reproducing element for reproducing recorded signals from recording tracks of a rotary recording medium, a holder having said reproducing element mounted at its tip end, a cantilever having the rear end of said holder mounted at its tip end, force applying coil for applying a force to the rear end side of the cantilever so that the reproducing element makes contact with the rotary recording medium having a predetermined pressure, and control coils for applying force at the rear end side of the cantilever so that tracking control is performed, by displacing said reproducing element in a direction perpendicular with respect to the longitudinal direction of the recording tracks of the rotary recording medium. The cantilever, holder and reproducing element constructs a cantilever assembly, the holder forms a plate-shaped member in which the width in the direction substantially parallel to the rotating surface of the rotary recording medium is larger than the length in the direction perpendicular to the rotating surface, and the holder and the cantilever assembly have a first resonance frequency respective of their spring constant and moment of inertia wherein said resonance frequency is selected at a frequency lower than a frequency f.sub.c at which the response of the servo loop open loop characteristic of the control means becomes zero. The above cantilever has the first resonance frequency at the plane substantially parallel to the rotating surface of the rotary recording medium selected at a frequency higher than the frequency f.sub.c at the rear end side thereof.

Dependencies are inferred from the claim text.