| 摘要 |
PROBLEM TO BE SOLVED: To easily form a signal in a different optical disk in recording density with a simple optical system and also to perform precise tracking with a good characteristic of a tracking signal. SOLUTION: Irradiating light from a light source is splitted into plural beams, and a main beam 12 among the plural beams is converged on a prescribed track of a recording medium, while side beams 13 and 14 are converged in positions across the track, and a part of the main beam reflected by the recording medium is splitted into 4th and 5th beams having a different optical axis, and the side beams reflected by the recording medium and the 4th and 5th beams are received by a photodetector 7. |
