| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that proper recording, erasing and reproducing cannot be performed because sudden fluctuation in an FE signal occurs if there is an obstacle such as waviness, damage or dust on an optical disk surface, a focus servo cannot follow to increase focus shifting if the signal fluctuation is very sudden, thereby the effective laser power is reduced during recording. <P>SOLUTION: Normal recording laser power and focus shifting laser power (fixed magnification of normal recording laser power) are preset in a laser driver, the former power is used in a normal case where a focus error is within a fixed range, and the latter laser power is used when the focus error exceeds the fixed range and the effective laser power is reduced by focus shifting, so as to induce the performance of securing information reliability. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
