| 摘要 |
PURPOSE:To improve the measuring precision of a semiconductor laser output by head positioning the diferential outputs of two pieces each of quadripartite photodetectors while watching a spot position by an oscilloscope. CONSTITUTION:The photodetector 2 is quartered to A-D, and the outputs of the divided parts A, C are inputted to a differential circuit 7 and the outputs of the divided parts B, D are inputted to the differential circuit 8. The output differences (A-C) and (B-D) of respective divided parts are outputted from the circuits 7, 8, to be inputted to the X, Y axes of the oscilloscope. Then, the center of an incident luminous flux on the photodetector 2 is detected by making to coincide the spot with the intersected point of both axes. Thus, the photodetector 2 is positioned precisely for the luminous flux by moving a head and making to coincide it with the intersected point of both axes while watching the spot position on the oscilloscope, and the output of the semiconductor laser being a pickup light source is measured at the position. The output is displayed on an output display part as the sum of the outputs of the quadripartite A-D of the photodetector 2. |
