OBJECT DETECTION SENSOR UNIT

摘要

PURPOSE:To enable the setting of a detection area according to the background at the measurement, by measuring the distance to the background object for each of detection sensors with no object to be detected set to detect an object being detected using the distance as reference value. CONSTITUTION:An object detection sensor unit 16 measures the distance to an object to determine detection areas (a)-(c) peculiar to light receiving elements 3-5, which detect objects. Respective distance data of phase comparison circuit 13 are read into an arithmetic circuit 23 of a microcomputer 9 and peculiar detection areas (a)-(c) of the object detection sensor unit 16 are converted into data corresponding to the distance about 20cm ahead of the objects to be written into a memory circuit. Therefore, when any foreign object is in the detection areas (a)-(c), the input voltage of a comparator 14 which has values corresponding to the detection areas (a)-(c) of the memory circuit is compared with the reference voltage and an output voltage appears at the comparator 14 to perform an action such as sounding an alarm. This enables the setting of detection areas according to the background at the measurement.