| 摘要 |
PURPOSE:To improve recording and reproducing characteristics of CNR, BER, etc., in a high density area and also to reduce cost by recording and/or reproducing by means of a laser beam having a square cross-section. CONSTITUTION:An outgoing light 2 is made parallel rays of light 4 by a collimator lens 3, made a square cross-section by a square diaphragm 6 and converged on the recording face of a magneto-optical disk 9 in a nearly square cross-section by means of an objective lens. In this case, the parallel rays of light 4 are used in an elliptic shape as they are without the use of a beam shaping prism, which, by making the major axis of the ellipse coincide with the radius direction of the optical disk, the distribution of light intensity of the beam at the time of recording is uniformized with the radius direction of the optical disk, and the formation of more straight edge is facilitated. |
