| 摘要 |
PURPOSE:To prevent recording error or erasing error, etc., from being generated by controlling the power of a laser beam in the case of recording, reproducing and erasing by adjusting the pulse width of the laser beam to be emitted. CONSTITUTION:When controlling the power of the laser beam which is emitted in the shape of a pulse for executing recording, reproducing and erasing to a recording medium, the prescribed laser beam power in the case of recording, reproducing and erasing is executed effectively by controlling the pulse width of the laser beam. In this case, laser pulse emission is executed with a constant waveheight value, in the case of reproducing, the pulse width is shortened so as to reduce an effective output and in the case of recording and erasing, the pulse width is extended so as to enlarge the effective output. Therefore, the respective modes of recording, reproducing and erasing can be switched and concerning the power of the laser beam, it is enough to only execute control so that the power can maintain the constant waveheight value. Any transitional phenomenon is not generated. Thus, there is no delay in the rise of the power of the laser beam, and recording error or erasing error is prevented from being generated. |
