SEMICONDUCTOR PHOTODETECTING ELEMENT FOR DIGITAL RECORD READING AND OPTICAL PICKUP DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a photodetecting element for digital record reading with high-speed time response which can make a high-precision read when high- density records are reproduced by using a short-wavelength laser and to provide a semiconductor photodetecting element for digital recording and recording and an optical pickup device which detect light signals of signal systems having different wavelengths at the same position with high precision. SOLUTION: The semiconductor photodetecting element for digital record reading includes a semiconductor layer 21 which includes at least one element among group-III elements and at least one element among group-V elements and electrodes 20 and 22 which are arranged on both the sides of the semiconductor layer 21 opposite; and at least one electrode 22 has an area of <=5 mm2 or electrodes of <=5 mm2 in area are provided. An optical pickup device using this semiconductor photodetecting element for digital record reading is provided.