A tilt servo control device of an apparatus for recording information on and
reproducing
information from an optical recording medium, the apparatus comprising an optical
system for leading a laser beam emitted from a light source to a recording surface
of the optical recording medium and a laser beam reflected by the recording surface
of the recording medium to a split type photo detector and a read signal generator
for generating a read signal in accordance with an output signal of the photo detector.
The tilt servo control device generates a push-pull component signal including
a differential component of output signals of respective split portions of the
photo detector, generates a tilt error signal representing a tilt angle at a position
of the laser beam irradiating the recording surface and an optical axis of the
laser beam based on the push-pull component signal, and drives a tilt angle adjuster
for adjusting the tilt angle so as to reduce the tilt error signal.
