Reflectors in traffic engineering
We encounter reflectors in many different ways in our daily lives, including in the important traffic engineering sector. Retroreflectors are safety devices which, particularly in the dark, reflect incident light back to the light source. The special optical, chemical and mechanical properties of glass ensure that this material finds many uses in the challenging traffic engineering sector. Its hardness and heat resistance are enough to ensure that it is often preferred to plastics.
Requirements for good reflective properties
The precise formation of the so-called triple reflector surface and the accuracy of this triple angle are the decisive factors when it comes to the quality and reflective properties of the device. Careful attention to detail and accuracy must be paid to the technical details when manufacturing such a device. Computerised calculations are often used to produce optimal reflection.
Cat’s eyes reflect light
Reflectors are known colloquially as cat’s eyes and not without good reason. The eyes of a cat or indeed other nocturnally active animals have the same characteristics needed to reflect incident light. Glass cat’s eyes work using rotation-symmetrical glass bodies, which are comparable to the middle part of the human eye in form and also function in a similar way. The back („retina“) is mirrored and lies in the focus of the front curved surface, which creates a convex lens. Front and back have the same centre of curvature, so that the cat’s eye functions just as well if the light falls at an angle. Traffic safety As already mentioned, the use of retroreflectors on roads increases safety at night. If retroreflectors are illuminated by the headlights of a car, they reflect the light very brightly back towards the car. Reflectors, reflective strips and – particularly in the UK – cat’s eyes built into the road surface are most often used in road traffic. In safety applications, reflective materials should always be combined with diffuse reflecting surfaces, so that they can also be seen when illuminated by extraneous light from other directions. For this reason delineators not only have reflectors, they are also painted white. For road markings, glass beads are used in the marking material, creating retroreflection which increases visibility at night. Schäfer Glas manufactures different glass reflectors which are used for various different purposes. We are continually developing our production processes, in close cooperation with our customers.