Patent 7660221 was granted and assigned to Pegatron on February, 2010 by the United States Patent and Trademark Office.
An optical disk differentiating method applied to an optical disk drive, in which a first level value, a second level value and an optical disk differentiating value generating program are stored and an optical disk is put. The method comprises the steps of: generating a laser beam impinging on the optical disk; generating a first reflex signal when the laser beam is reflected by a surface of the optical disk; generating a second reflex signal when the laser beam is reflected by a reflex layer of the optical disk; calculating a first time frame value when the first reflex signal is greater than or equal to the first level value, and rendering a first beginning time value when the first reflex signal firstly equals the first level value; enabling the optical drive to obtain an optical disk differentiating value according to the first time frame value and the optical disk differentiating value generating program; calculating a second beginning time value as the second reflex signal firstly equals the second level value; calculating a difference between the second beginning time value and the first beginning time value and defining the difference as a response time value; and comparing the response time value with the optical disk differentiating value to determine a type of the optical disk.