| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which can prevent offsets in the focusing signal and correct the spherical aberration caused by the substrate thickness difference while thinning its device height. <P>SOLUTION: A flat parallel surface plate 5 is placed between the beam splitter 3 and the collimator 6 to correct the spherical aberration caused by the thickness difference of the transparent substrate for the first and second information recording layer 9a, 9b of an optical disk 9. The spherical aberration is corrected by moving the flat parallel surface plate 5 back and forth along the light path, or by inserting one of the flat parallel surface plates different in thickness. <P>COPYRIGHT: (C)2007,JPO&INPIT |
