Patent ID: 6061318
Filing Date: 2000-05-09
Classification: G11B

Abstract:
A method for discriminating a type of an optical disc loaded into a digital versatile disc system which can reproduce a plurality of optical discs having different signal record layers with a single optical pickup, the method for discriminating the type of the optical disc comprising the steps of:(a) detecting a focus error signal having desired waveforms from a signal picked up from the loaded optical disc in a focus-up state during performing an initial focus search operation for the loaded optical disc;(b) comparing a magnitude of the focus error signal in said step (a) with first and second predetermined reference values;(c) determining which of a reflection characteristic curve having a minute level produced by reflection from a surface of a substrate of the loaded optical disc, a reflection characteristic curve having a magnitude between the first and second predetermined reference values produced by a reflection layer of the loaded optical disc, and a reflection characteristic curve having a magnitude larger than the first and second reference values forms the focus error signal detected in said step (a), based on the comparison result in said step (b), and setting the time elapsed after a start of a focus-up operation of the optical pickup;(d) counting a number of times when the focus error signal detected in said step (a) is determined as the reflection characteristic curve having the magnitude between the first and second predetermined reference values in said step (c);(e) comparing the number of times counted in said step (d) with a predetermined number, and the time elapsed set in said step (c) with a predetermined critical time, respectively, when the focus-up operation is completed; and(f) determining whether the loaded optical disc is a single-layered DVD, a multi-layered DVD or a CD, based on the comparison results in said step (e).