Patent ID: 6411577
Filing Date: 2002-06-25
Classification: G11B

Abstract:
An optical disc discrimination method for discriminating between at least two types of optical discs having record densities of recorded information, different from each other, comprising the steps of:driving the optical disc to be discriminated to rotate; performing at least a focus servo operation as a servo operation to irradiate a read-out light beam on said optical disc to be discriminated and receiving a reflected light beam from said optical disc to be discriminated to obtain an RF (Radio Frequency) signal; converting said RF signal into binary digits as a pulse train signal; counting the number of pulses in said pulse train signal for a predetermined time when rotation of said optical disc is accelerating; comparing a count value during said predetermined time with a threshold value; and determining said optical disc to be discriminated to be one of said at least two types of optical discs, having a least amount of recording density, when the count value within said predetermined time is equal to or less than said threshold value.