Glossary · Automation fundamentals, platforms and components
Reflector
Also known as: Retroreflector
German: Reflektor
In sensor technology, a reflector is a passive optical element, usually a retroreflector with prism or microprism structure, that returns the light beam of a retroreflective photoelectric sensor or light barrier back toward the emitter, so that interruption of the beam can be detected.
- Automation components
In one sentence
A reflector returns the light of a retroreflective photoelectric sensor to its receiver, so an object interrupting the beam is detected.
Example
A retroreflective sensor with a polarizing filter and matching prism reflector detects shiny cans on the conveyor without being fooled by their surface.
How it applies
- Engineering: Retroreflective sensors need wiring on one side only. Polarizing filters combined with prism reflectors help to ignore glossy objects. Reflector size and type limit the operating range stated by the sensor maker.
- Maintenance: Dirty, misaligned or damaged reflectors cause false detections. Include them in cleaning and inspection routines.
- Documentation: Spare parts lists should name the approved reflector type; replacing it with a different reflector or reflective tape can change the sensor's range and behavior.
Reflector-based sensors vs. safety light curtains
A standard retroreflective sensor is not a safety device. Protective functions need safety-rated equipment such as a Safety light curtain; unapproved reflective surfaces near safety sensors can even impair their function.