| 摘要 |
PURPOSE:To obtain a light detector wherein the dynamic range of a photocurrent is suppressed low and noise is reduced, by providing a light blocking layer having a light previous window, of which the width is successively reduced from the central part thereof toward the end part thereof where at least one of electrodes is present, on a P-type high resistance layer. CONSTITUTION:A P-type high resistance layer 2 is formed to the entire surface of a high resistance N-type substrate 1 and electrodes 3, 3' are provided to two opposed end parts of said P-type resistance layer 2, and a low resistance N-type layer 4 and an electrode 5 are provided to the back surface of the substrate 1. A light irradiating window 12 is formed to the light blocking layer 10 so as to successively become narrow from the central part thereof toward one electrode. By this method, the optical noise from a part not irradiated with signal light can be reduced. The quantity of light increases at the time of close range but the dynamic range of a photocurrent can be suppressed low by reducing the size of the light irradiating window. |
