| 摘要 |
PURPOSE:To attain the precise control of a light quantity on the face of a recording medium by detecting a reflected light of the recording medium irradiated by a light source, correcting an error signal by the use of the output signal of the reflected light, and correcting the attenuation of the light quantity on the face of the recording medium. CONSTITUTION:This controller is equipped with a photodetecting means 2 arranged proximately to a light source 1 where an information recording medium 5 is irradiated with luminous flux, a means 12 which compares the photodetecting signal with a reference quantity and outputs the error signal a means 14 which drives the light source 1 to emit a prescribed light quantity based on the error signal, and a means 7 which detects the reflected light of the recording medium 5 irradiated from the light source 1. Then, the error signal is corrected by the use of the output signal of the means 7, and the attenuation of the light quantity on the face of the recording medium 5 is corrected. Thus, the attenuation of the light quantity caused by dust, etc., can be corrected and the light quantity on the recording medium 5 can be precisely controlled. |
