Patent ID: 7944801
Filing Date: 2011-05-17
Classification: G11B

Abstract:
1. An apparatus for effecting at least one of recording and reproducing information, said apparatus comprising: a first light source having a light intensity and for emitting a light beam having an emission wavelength; a second light source having another light intensity and for emitting a light beam having an emission wavelength different from that of the first light source; a first photodetector capable of generating an output; a second photodetector capable of generating an output; an optical system configured to guide a light beam emitted from the first light source to a recording medium and to guide a light beam reflected from the recording medium to the first photodetector; another optical system configured to guide a light beam emitted from the second light source to the recording medium and to guide another light beam reflected from the recording medium to the second photodetector; a separating optical element configured to guide the light beam emitted from the first light source to the second photodetector, the second photodetector receiving the light beam and generating an output based on the received light beam; and a control circuit for receiving the output generated by the second photodetector, and being configured to control the light intensity of the first light source based on the output of the second photodetector.