| 摘要 |
PURPOSE:To offer a laser driving device which can correct the decrease of light output due to thermal equilibrium so that the light output after being decreased because of the thermal equilibrium becomes a prescribed value for recording, and can execute the optimum recording in the case that a semiconductor laser is driven at an open loop by a constant current. CONSTITUTION:The semiconductor laser 1 is made to emit the light output for the recording by driving it by the constant current, and difference between the light output for the recording at the beginning of drive by the constant current and the light output after the lapse of prescribed time is detected by a light output difference detecting means 20. A driving current or control voltage corresponding to the difference of the light output is calculated by a computing element 26. At the time of the recording, the driving current IAD calculated by the computing element 26 and corresponding to the difference of the light output is added to the constant current IL. Thus, in the case that the semiconductor laser 1 is driven at the open loop by the constant current, the decrease of the light output due to the thermal equilibrium is corrected so that the light output after the decrease due to the thermal equilibrium becomes the prescribed value for the recording, and the optimum recording can be executed. |
