| 摘要 |
PURPOSE:To prevent formation of a it by a bottom level so as to improve the S/N, by releasing the superposition of high-frequency signals of a light source and making the level of a bias driving current lower than that of the reproducing time at the time of recording. CONSTITUTION:A light source 9 which generates prescribed light, a 1st current feeding circuit which supplies a 1st driving current to the light source 19 at the time of the recording mode and reproducing mode, a 2nd current feeding circuit which supplies a 2nd driving current which changes in corresponding to recording signals at the time of the recording mode, with the 2nd current being superposed upon the 1st current, a 3rd current feeding circuit which supplies a 3rd driving current under a condition where the 3rd current is superposed upon the 1st current at the time of reproducing mode, and a generating circuit 20 which generates high-frequency signals to be supplied at the time of the reproducing mode are provided. At the time of the recording mode, modulated 2nd driving current is supplied in state where the 2nd current is superposed upon the 1st current and, at the time of the reproducing mode, the 3rd driving current is supplied in condition where the 3rd current is added to the 1st current and high-frequency signals are superposed. Therefore, the bottom level of the output of the light source at the time of recording can be made equivalent to or lower than the level of the reproducing time and, as a result, the S/N is improved. |
