Patent ID: 6521878
Filing Date: 2003-02-18
Classification: G01B,G11B

Abstract:
A radial tilt detector for an optical disc information recording/reproduction apparatus which includes an optical head for projecting a condensed beam of light on a recording surface of a rotating optical disc and receiving the projected beam, of light reflected from said recording surface of said optical disc, a focus actuator for focusing said condensed beam of light an its projected position of said recording surface of said optical disc, and drive means for outputting a drive signal to drive said focus actuator, said radial tilt detector being adapted to detect a radial tilt which is a tilt amount in a radial direction of said recording surface of said optical disc and comprising:velocity detection means responsive to said drive signal from said drive means for detecting a velocity in a direction depending en an optical axis of said light bean at said position focused by said focus actuator; and radial tilt calculation processing means for calculating said radial tilt on the basis of said velocity detected by said velocity detection means and the number of rotations of said optical disc.