| 摘要 |
PURPOSE:To obtain a device capable of making it hardly influenced by the environment of temperature and humidity or the like and selecting an optimal power by measuring the upper limit threshold value of the recording power of each disk while considering the variation of a disk characteristic, and searching the optimal recording output of a semiconductor laser from the value. CONSTITUTION:A 3T pattern being the maximum recording frequency is recorded at the arbitrary position of the recording face of a disk 1 by an arbitrary recording power. Next, the recording part is read, the amplitude value of a data signal is measured, and an amplitude value A is obtained. Then, a 8T pattern being the minimum frequency is recorded at the same part by the same recording power as that at the time of recording the maximum recording frequency, the recording part is read, and the amplitude value B of the data signal is obtained. The rate B/A of the amplitude of those data signals is used as a resolution at 5.0mW, and when the resolution is more than 40%, the resolution is searched again. The optimal power is 1.5mW less than the upper limit threshold value at the resolution 40%. Therefore, a value obtained by subtracting 1.5mW from a recording power PH obtained from the upper limit threshold measured value is used as the optimal recording output value. |
