| 摘要 |
PURPOSE:To reduce the power consumption of an optical disk device by reducing the heat generation of a high frequency superimposing means and, at the same time, to suppress radiation noise and the noise of a semiconductor laser. CONSTITUTION:The optical disk device is provided with a semiconductor laser driving means 18, high frequency superimposing means 42, high-frequency current amplitude changing means 46, focus controlling means 27, tracking controlling means 34, reproduced signal amplitude detecting means 47, and noise amplitude detecting means 48 and 49, and from the output signal from the noise amplitude detecting means 48 and 49, and the reproduced signal amplitude detecting means 47, the ratio of the amplitude of reproduced signals to that of noise at the time of reproducing information is found. The means 46 is controlled by means of a high-frequency current amplitude controlling means 19 so that the ratio can become larger than a prescribed value. |
