| 摘要 |
PURPOSE:To make the noise level low and to improve a C/N by inserting the mask having the cross-shaped slit into the light path of the optical pick-up. CONSTITUTION:Between a semiconductor laser 1 and a polarizing beam splitter 4, the cross-shaped notch, namely, a mask 15 having a slit 14. Thus, by inserting the mask 5 having the cross-shaped slit 14 into the light path of the laser light, the polarization in the intermediate condition including both a P polarization component and an S polarization component to exist between the polarizing angles of 90 deg. formed by a P polarization and an S polarization can be satisfactorily removed, and the deterioration of a C/N can be also prevented.
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