Pepperl Fuchs Photoelectric Diffuse Mode Sensors

Diffuse mode sensors are particularly easy to install, since only one device has to be fitted and no reflector is required. These sensors operate primarily at close range, feature optimum switching accuracy, and can reliably detect even very small objects. The sensors with background suppression sense only a specific area in front of the sensor. The sensor ignores any objects that are outside of this area. Sensors with background suppression are also insensitive to interfering objects in the background and are still extremely precise. Sensors with background evaluation are always used in applications with a fixed background in the measuring range with which you can align the sensor.

Figure 1 – General mechanism of diffuse reflection by a solid surface (refraction phenomena not represented) Figure 2 – Diffuse reflection from an irregular surfaceDiffuse reflection from solids is generally not due to surface roughness. A flat surface is indeed required to give specular reflection, but it does not prevent diffuse reflection. A piece of highly polished white marble remains white; no amount of polishing will turn it into a mirror. Polishing produces some specular reflection, but the remaining light continues to be diffusely reflected.