| 摘要 |
PURPOSE:To enable the accurate measurement by measuring in advance a driving current of a laser and characteristics of a light output prior to controlling the quantity of laser light and setting the driving current according to said measurement. CONSTITUTION:The quantity of laser light is monitored to control the driving current by a laser control circuit 14 so as to make the the quantity of light constant. Then, the characteristics of the laser 4 are measured in a prescribed area of a disk 1 under the state of a focusing control and a tracking control and also in a part where information such as address data, etc., capable of recording and reproducing data is not recorded. This is for the purpose of making a quantity of return light to the laser 4 the same in condition as in the case of actually recording and erasing data. By this method, the accurate measurement of the characteristics can be performed. |
