| 摘要 |
PURPOSE:To improve the service life of a semiconductor laser used as a light source by using a small power to obtain a preheat effect at the front ridge and a large power level to obtain pit formation at the rear ridge as the recording power. CONSTITUTION:A write data (a) is inputted to one-shot circuits OSA 2, 3 to form a write pulse (b) and a delay signal (c) of an opposite polarity respectively having time widths T1, T2. The signals (b, c) are inputted to an AND circuit 4 and a power-up signal (d) outputs a current I2 from a current source CSB 7. On the other hand, a current source CSA 6 outputs a current I1. thus, a current switch circuit 8 has a current I1 from the front ridge of the write pulse (b) up to a time T2 and has a current I1+I2 from the time T2 up to the time T1. Then a head drive current (e) of the circuit 8 is fed to a semiconductor laser diode 10 in the optical recording head 9 to be an optical output P, the output P is converged by an optical lens in the head 9 to form a pit 12 to an optical storage medium 11. |
