| 摘要 |
PURPOSE:To obtain a higher data density and a higher data transfer rate by recording information using the combination of the beginning and the ending of a mark. CONSTITUTION:Against the laser beam components reflected from an arbitrary single track, which is a recessed track 22 or a projected track 25 acting as an information recording carrier, the laser beam components reflected from left and right tracks have phase differences corresponding to the optical path lengths caused by the difference in levels. If the phase differences are properly selected, the effect caused by the marks on adjacent tracks is made small. A difference in level d which generates a good phase difference, becomes about d=lambda/(6.n) to lambda/(3.n) where lambda is the wavelength of a reproduced laser beam and n is the refractive index of the information recording carrier substrate. |
