| 摘要 |
<P>PROBLEM TO BE SOLVED: To form a good spot by removing residual astigmatism generated when a coma aberration caused by the tilting of an optical recording medium is corrected by tilting an objective lens. <P>SOLUTION: When a comma aberration caused by the tilting of an optical recording medium 108 is corrected by tilting an objective lens 107, astigmatism is generated in an optical beam emitted from a semiconductor laser 101 by the tilt correction of the objective lens 107. A phase correction element 105 for correcting the astigmatism is arranged. A phase difference is given to the optical beam according to a driving voltage applied to the phase correction element 105. The wave surface of a passing optical beam is not changed when reference phases are given to the optical beam in all the divided areas of the phase correction element 105. Positive and negative phase differences are given to the passing optical beam according to the applied driving voltage, and the occurrence of a coma aberration and astigmatism is suppressed to form a good spot on the optical recording medium 108. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
