| 摘要 |
PURPOSE:To obtain a highly functionable array-light source optical pickup device, by assembling an array type semiconductor laser having three or more luminous points in the device. CONSTITUTION:Only the optical beam from one luminous point of an array 1 is separated by a knife-edged mirror 9 and led to an optical system for error detection and all of the other beams are received by a photodetector 8. The other luminous points are driven by a laser driving circuit 14 at different frequencies. The luminous point B is driven by a direct current and points C and A are driven by the signals of different frequencies. When the driving frequencies are selected in such a way that they can be sufficiently higher than the frequency of information signals, the reflecting light from a spot becomes an amplitude-modulated signal by using the driving frequencies as a carrier. Therefore, when the amplitude-modulated signal is passed through a band-pass filter 15, whose center frequency is the carrier frequency, and detected by means of a driving frequency signal, information can be obtained from a necessary spot. |
