| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device in which a high speed recording/reproducing is conducted. SOLUTION: In the optical information recording and reproducing device, the recording surface of an optical information recording medium is irradiated with plural light spots by a semiconductor laser and the information tracks are scanned to record information and/or to reproduce the recorded information. The device is provided with the optical head having the semiconductor laser and a diffraction grating 101, which is divided into plural diffraction grating sections having mutually different grating constants, the means, which vertically arranges the major axis direction of an elliptical luminous flux 104 emitted from the semiconductor laser and the dividing lines of the diffraction grating 101, and the means which sets the major axis direction of the flux 104 in parallel or normal against the information tracks. |
