| 摘要 |
PROBLEM TO BE SOLVED: To use without changing wavelengths of used laser and changing the numerical operture of an object lens irrespective of a data carrier of different memory density. SOLUTION: In order to operate optical data carriers IT1, IT2 of different memory density, wavelengths and the numerical operture which adjusts supreme memory density are provided, a plurality of auxiliary beams E, F, G, H which adjust respective track widths are provided and an optical system having pairs of a plurality of auxiliary beam detectors corresponding to a plurality of different data carriers is used. Thereby, in a compatible memory device and/or regenerator, each of data of the optical data carrier IT2 of low memory density, namely a data signal, is reconstructed using means for detecting rising of a signal of the data carrier IT2 detected from the data carrier IT2 by a main beam M. |
