| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing apparatus which can simply correct spherical aberration in a short period of time. <P>SOLUTION: The optical information recording and reproducing apparatus includes; a focus error 104 which detects a focus error between an optical spot and an optical recording medium; a focus servo loop which performs focus control based on the focus error; an offset adding circuit 105 which impresses an offset to the focus servo loop; a means 210 prepared between a semiconductor laser 201 and an objective lens 211 to make a luminous flux include the spherical aberration; and a means to hold a relation between the amount of spherical aberration and the amount of focus offset generated in connection with it. When the spherical aberration is corrected by driving the spherical aberration generation means 210, the offset is impressed based on the relation held in the holding means. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
