| 摘要 |
PURPOSE:To discriminate wave length with superior characteristics using only electric circuits by a method wherein the output of a semiconductor photo-detector is processed by electric operational circuit utilizing the spectral sensitive characteristics of the detector. CONSTITUTION:A wave-length discrimination type photo-detector is constructed by connecting an operational circuit to the output side of a semiconductor photo- detector obtained by providing P-N Junctions 2, 3 on a semiconductor which has more than two kinds of the different energy of forbidden band width, and connecting lead wires 5, 6 and 4 to each junction. If it is assumed that the wave lengths are L1, L2, and the spectral sensitive characterisrics of detectors A and B21, B22 are each 18, 19, the detecting portion B22 responses to only light L1, letting a light current L1(t) flow. The detecting portion A21 responses to both L1, L2 light, producing an output L1(t)+L2(t). Therefore, the difference L2(t) in outputs between the detecting portions of A and B via a differential amplifier 23 can be taken out. Thus, it is possible to discriminate wave lengths with superior characteristics using only electric circuits. |
