| 摘要 |
PROBLEM TO BE SOLVED: To minimize the interference between a spot and a ring zone by the pits, which are adjacent to each other in tangential and radial directions, and to obtain optimally reproduced signals by tilting the major axis of the ellipse of the spot against the pit columns on a high density optical disk for an appropriate angle within a specific angular range. SOLUTION: In a semiconductor laser 70, a PN joint surface 700, which emits light beams, is tilted for an angle (90 deg.-θ) against an x-y plane through the rotation about a y direction as an axis. Moreover, the optical axis formed among a luminous flux separating means 92, a collimating lens 91 and a mirror 93 is set to normal against the line which connects the center of an objective lens 900 and the center of an optical disk. By forming the above, the spot formed on a high density optical disk 50 is irradiated under the condition in which the major axis of the ellipse of the spot is tilted for an angle θ with respect to the pit columns. By setting the angle θ to an appropriate value, which is more than 45 degrees and less than 66 degrees, optimally reproduced signals are obtained. |
