| 摘要 |
<P>PROBLEM TO BE SOLVED: To more improve the accuracy of focusing in accordance with the different characteristics of individual optical pickups. <P>SOLUTION: An optical disk drive is provided with a control part 31 for generating a focus error signal SF to be changed in accordance with focus displacement D which is a distance from the focus of an emitted light beam L1 to the a signal recording surface 8A on the basis of a change in the light quantity of reflected light beam L2 obtained by reflecting the emitted light beam L1 on the signal recording surface 8A, a non-volatile memory 32B for storing characteristic data indicating relation between the focus error signal SF and the focus displacement D and a control part 31 for calculating the focus displacement to be generated by focus servo operation on the basis of the focus error signal SF and the characteristic data and moving an objective lens 7 on the basis of the focus displacement D to perform focus servo operation. Consequently optimum focusing can be performed on the basis of previously measured characteristics. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
