| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup and optical information recording/ reproducing device in which minute mark recording is possible by a super resolution spot and in which no signal deterioration is caused due to increase in a side lobe at the time of reproduction. SOLUTION: A super resolution spot is formed on the recording layer of an optical disk 5, by using a variable phase filter 3 that has three areas 3a-3c capable of producing phase difference in level in the radial direction, and by imparting π phase difference in level between the center area 3b and the areas 3a, 3c on both sides at the time of recording. In the case of reproduction, the phase difference in level is made zero in the areas 3a-3c of the variable phase filter 3, thereby forming an optical spot of a normal diffraction limit causing less side lobe. The variable phase filter 3 can be composed of a homogeneous orientation liquid crystal element. |
