| 摘要 |
PROBLEM TO BE SOLVED: To provide a photoelectric sensor capable of carrying out an object detection based on the rate of change in a level of received light and detecting an object to be detected in response to its moving speed. SOLUTION: The photoelectric sensor 10 is provided with a light projecting element 11 projecting light toward a detection region where the object to be detected moves, and a light receiving element 12 receiving light from the detection region and outputting light reception signals corresponding to the amount of the received light. In the photoelectric sensor 10, the amount of changes for a prescribed reference period is detected as the rate of change in the received light level of the light reception signals, and by comparing the rate of change with a prescribed reference value, the detection of the object to be detected is carried out. In above detection method, a period setting means setting the reference period variable and a reference value setting means setting the reference value variable are employed therein. COPYRIGHT: (C)2004,JPO&NCIPI |
