| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam-shaping prism for an optical pickup capable of allowing optical beams having different polarization conditions on an outward path and on a homeward path to be efficiently passed therethrough on both of the paths. SOLUTION: A beam-shaping optical system 20 includes two beam-shaping prisms 22 and 24. These beam-shaping prisms 22 and 24 have non-parallel surfaces 22a, 22b and 24a, 24b, respectively, each of these surfaces being crossing an optical axis. Among those surfaces, the surfaces 22a and 24a positioned closer to a semiconductor laser are obliquely disposed with respect to the optical axis, while the other surfaces 22b and 24b closer to a magneto-optical disk are disposed to be perpendicular to the optical axis. An anti-reflection film is formed on each of the surfaces 22a and 24a disposed to be closer to the semiconductor laser and obliquely crossing the optical axis, i.e., on each of beam-shaping surfaces 22a and 24a. |
