| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that it is difficult to appropriately detect a control signal in recording and/or reproducing since reflected light from a recording layer, which does not undergo the recording and/or reproducing, enters a photodetector concurrently with reflected light from a recording layer which undergoes the recording and/or reproducing when recording on and/or reproducing from an information recording medium having a plurality of recording layers is performed. <P>SOLUTION: A polarization hologram is used to diffract light output from a light source and to generate a main beam, which is a zeroth-order light beam, and a pair of sub beams, which are a positive first-order light beam and a negative first-order light beam each having a polarization direction perpendicular to a polarization direction of the main beam. Therefore, it is possible to obtain an accurate control signal from the detected light beam of the sub beams, and also possible to realize an optical pickup device having a preferable recording performance. <P>COPYRIGHT: (C)2009,JPO&INPIT |
