| 摘要 |
PURPOSE:To improve the sharpness of resonance of a resonance circuit by connecting the resonance circuit with a photoelectric conversion element in series or parallel and connecting the photoelectric conversion element with a diode in series. CONSTITUTION:A resonance circuit 6 is operated as a tuning circuit in order to extract only photoelectric current resonated at the resonating circuit among photoelectric current (Il)7 generated at a photodiode(PD)1. A diode (D1)3 which is connected so as to permit the photoelectric current 7 to be in the forward direction is inserted to prevent the sharpness (Q) of resonance of the resonance circuit from deteriorating, and reverse electromotive current caused by the inductance of the resonance circuit is prevented. Since the insertion of the diode 3 keeps the sharpness Q of resonance of the resonance circuit high, the tuning characteristics are improved and only the resonance frequency component is selected from the photoelectric current. |
