Patent ID: 6327234
Filing Date: 2001-12-04
Classification: G11B

Abstract:
A method for discriminating at least two kinds of optical discs which are different in thickness, in an optical disc player having an optical pickup (22), a focus error producing circuit (23) and a peak hold circuit (24), comprising the steps of:resetting a value in the peak hold circuit;moving the pickup toward an optical disc to a first predetermined position (UH) along an optical axis of the pickup;irradiating a laser beam from the pickup on a recording surface of the optical disc;moving the pickup toward a second predetermined position (UL) from the first predetermined position at a predetermined set speed;receiving a laser beam reflected from said recording surface and producing a focus error signal (FE);holding a peak value of the focus error signal in the peak hold circuit;starting to count a time (T) from when a value of the focus error signal becomes equal with a first reference value (TH1);resetting the value in the peak hold circuit when the time becomes equal with a first predetermined time (T1), and continuing to hold the peak value in the peak hold circuit;detecting a difference between the held value in the peak hold circuit when the time becomes larger than a second predetermined time (T2) and a second reference value (TH2), and discriminating the kind of the disc based on the detected difference which is different in accordance with the kinds of discs.