| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device which can perform excellent aberration correction to each layer of a multilayer recording medium and realize stable recording or reproduction. <P>SOLUTION: The optical information recording and reproducing device is provided with: a beam expander 6 which corrects spherical aberration generated when focusing is made on a plurality of recording layers of an optical disk 11 by changing the divergent angle or convergent angle of light incident to an objective lens 10; and a correction means which corrects coma aberration generated due to the tilt of the optical disk 11. In this case, the coma aberration correction means is driven with different sizes of driving signals in accordance with the respective recording layers of the optical disk when the coma correction means is driven. Consequently, no coma aberration remains in any of recording layers even if the permeable layers of a multilayer recording medium are different in thickness. <P>COPYRIGHT: (C)2007,JPO&INPIT |
