| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device provided with a beam waveform forming means for changing an elliptic beam transmitted from a light source to a circular beam and an astigmatic aberration correcting means for compensating the astigmatic aberration of beam. SOLUTION: A beam waveform forming means is a cylindrical lens 120 provided between a light source 110 and a beam splitter 141, its cross section is the shape of a convex lens and converges an incident light beam e.g. in the direction X. An astigmatic aberration correcting means 131 is an astigmatic aberration lens and a concave lens for making a beam in one direction pass through and a beam in the other direction diverge. |
