Retroreflector

A retroreflector, also known as a reflector, is a passive optical component that reflects incident light largely back towards the light source. Unlike an active light, it does not produce any light itself and requires no electrical energy.

Retroreflectors are used in vehicle lighting to make vehicles more visible when illuminated by external light sources. Typical examples include the red reflectors on the rear of vehicles and on trailers.

The retroreflective effect is achieved, for example, by special prismatic structures or glass beads. Unlike a reflector, which is designed for targeted light shaping, a retroreflector is designed to return light as closely as possible to the direction of incidence.