| 摘要 |
PURPOSE:To incorporate an array-type semiconductor laser having three light emitting points in the titled device without complicating the optical system by providing the laser, a means to lead the light beam from one light emitting point to an error detector and that from another point to an optical detector, and a circuit to sequentially drive the other light emitting points and sample- holds the output of the optical detector. CONSTITUTION:The optical beam from one light emitting point of the array-type semiconductor laser 1 only is separated from those from other points by a knife edge mirror 9, and is made to enter a track error detector 11 and a focus error detector 13, and becomes an output for error detection. Meanwhile, the optical beams from two or more other light emitting points separated by the mirror 9 are all received by a photodetector 8 nd each of them is sequentially driven with a specific period determined by a timing circuit 15. The output from the detector 8 is made synchronized with the driving period of the laser 1, and is sampled by a sample holding circuit designated by the circuit 15, to be obtained as an output synchronized with the driving period of each light emitting point. |
