| 摘要 |
PROBLEM TO BE SOLVED: To adjust an astigmatism generated in an optical system. SOLUTION: In an optical disk device, to which a first optical disk having first double refraction, and a second optical disk having second double refraction larger than the first one can be selectively loaded, and which is provided with a liquid crystal element 31 between a light source 11 and an objective lens 15 for converging optical beams emitted from the light source to the loaded optical disk 2, by adjusting voltage applied to the liquid crystal element 31, a coma aberration is corrected in the first disk, and the astigmatism is corrected in the second disk. |
