| 摘要 |
PROBLEM TO BE SOLVED: To control recording power of a light beam accurately and quickly. SOLUTION: When an optical disk 1 is irradiated with a light beam for recording and a pit of length 3T-11T (T: reference period of length in the direction of track) is formed on the optical disk 1, a sample-and-hold circuit 5 samples and holds a reflected signal S1 from the optical disk 1 at the time of recording for the prescribed time in a range of T-3T from its trailing edge. A comparing circuit 7 compares a sample-and-hold value S4 with the prescribed reference level S5. and outputs its compared result S6. An ALPC(automatic laser power control) circuit 11 controls power of a light beam for recording based on the compared result S6. |
