AN OPTICAL DISC WITH DIFFERENT WOBBLE PATTERNS IN DIFFERENT GROOVES

摘要

The S/N ratio is improved for recording data to grooves ( 2 - 1,2 - 2 ) of an optical disc so that as much information as possible can be recorded at the lowest possible frequency band. An optical disc using wobble patterns to record different information has a first groove ( 2 - 1 ) having a first wobble pattern ( 22 ) in which one wobble period has a sharp rising edge and a gradual falling edge; and a second groove ( 2 - 2 ) having a second wobble pattern ( 24 ) in which one wobble period has a gradual rising edge and a sharp falling edge. Each of the first and the second wobble pattern is represented by a first fundamental and a second harmonic of a Fourier series. The polarity of the second harmonic, which is an even harmonic, of the second wobble pattern is opposite that of the first wobble pattern. A method for manufacturing this optical disc is also provided.