| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a device and method for detecting a body to be detected by a reliable photosensor where a detection level for determining the presence or absence of the body to be inspected can be easily set, parts costs are small, failure less occurs, durability is high, and the like. SOLUTION: A light-emitting device 2, and a photo detector 4 for receiving light from the light-emitting device are provided, the output level of the photo detector 4 changes by allowing a body to be inspected shields light from the light-emitting device 2, and the output level is compared with a preset detection level to detect the presence or absence of the body to be detected. The light- emitting device 2 is allowed to emit light in a beam attenuation mode where a beam is attenuated from a normal usage by a specific ratio, a detection level is set based on the output level of the photo detector 4 under conditions where no light is shielded by the body to be inspected, the detection level is stored in a memory 12, and the presence or absence of the body to be inspected is detected by the stored detection level.</p> |
