| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device that does not require a special high-cost optical component to cancel astigmatism and can adjust the intensity of astigmatism to be canceled according to the thickness and tilt angle of a plane-parallel plate. <P>SOLUTION: A plane-parallel plate 12 is arranged between a plane-parallel plate beam splitter 7 and a photodetector 14 while tilted in the direction rotated π/2 radians around the optical axis of laser light with respect to the beam splitter 7, and this plane-parallel plate 12 cancels astigmatism generated by the beam splitter 7. Consequently, an astigmatism optical element 13 which newly generates astigmatism is provided between the beam splitter 7 and photodetector 14 independently regardless of the astigmatism generated by the beam splitter 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
