Patent ID: 7420910

Claim:
An optical recording and reproducing method for recording and reproducing data from at least two types of optical recording media comprising: generating recording and/or reproducing light with a wavelength selected in a range of 780 nm±10 nm and transmitting the light via an objective lens with a numerical aperture NA selected in a range of from 0.45±0.01; reproducing data from first and second optical recording mediums with different recording capacities, said first optical recording medium having a track pitch in a range of from 1.5 μm to 1.7 μm and a groove depth in a range of from 70 nm to 90 nm, and said second optical recording medium having a track pitch in a range of from 1.2 μm to 1.3 μm and a groove depth in a range of from 150 nm to 180 nm.