| 摘要 |
PURPOSE:To detect the degree of fouling of an infrared-ray transmission window made of a photoelectromotive force element and prevent malfunction by incorporating an element which detects infrared rays in a package which has the infrared-ray transmission window. CONSTITUTION:The infrared detector obtains the output of a photoelectromotive force element 1 constituting the infrared-ray transmission window 1 from package pins 10 and 11 simultaneously with the output of an element 4 which performs detection by using infrared rays. Therefore, an infrared-ray input and a visible-light input are detected simultaneously. For example, when the infrared- ray transmission window fouls, the visible-light input and infrared-light input both decrease, so it is found that a decrease in infrared-light output is caused by the fouling of the infrared-light transmission window. When only the infrared- light input decreases while the visible light input does not decreases, a visible- light output and an infrared-light output are compared with each other to detect the decrease infrared-light output being caused not by the fouling of the infrared-light transmission window, but by the decrease in infrared-light input. |
