Optical disc and method for judging whether optical disc is placed reversely

A method for judging whether a double-sided optical disc is placed reversely into an optical disc drive, the optical disc drive comprising a first control module which is used to control a first optical pickup head and a second control module which is used to control a second optical pickup head, the first control module comprising the first optical pickup head, a first sled motor, a first radio frequency amplifier, a first driving circuit and a first digital signal processor, the second control module comprising the second optical pickup head, a second sled motor, a second radio frequency amplifier, a second driving circuit and a second digital signal processor, the method comprising steps of:

• loading the double-sided optical disc;
• allowing the first control module to control the first optical pickup head to emit a laser beam to a specified area of the double-sided optical disc and receive a reflected laser beam from the specified area;
• if the reflected laser beam generates an alternate brightness and darkness change and the intensity of the reflected laser beam processed by the first radio frequency amplifier generates a sinusoidal wave signal, confirming that the double-sided optical disc is not placed reversely;
• and
• if the reflected laser beam does not generate the alternate brightness and darkness change and the intensity of the reflected laser beam processed by the first radio frequency amplifier generates a stable direct current signal, confirming that the double-sided optical disc is placed reversely.