| 摘要 |
PURPOSE:To form a correct and large pit without causing a hindrance to the automatic tracking and automatic focusing by preventing the laser power from being lost completely at the leading correction period. CONSTITUTION:A recording pulse current generating circuit 1 receives a recording signal to generate a usual recording pulse current (b). Pulse edge detection circuits 2, 4 detect respectively the leading and trailing of the recording signal to generate a trigger signal (c). Correction pulse current generating circuits 3, 5 receive trigger signals c, e to generate correction pulses d, f of one bit length in both the polarities. The laser diode is driven by a current being the sum of the current (b), the correction pulse currents d, f and a DC bias current (g). On the other hand, a trailing setting circuit 11 decreases the power from the usual level in the trailing correction period but not made to zero so as to be a level or over by the control of the circuit 5. |
