Reflector foil
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Reflector foils , including reflective strips , are designed in such a way that they reflect incident light in the direction from which it comes (see also retroreflection ).
functionality
Reflector foils have a reflective background in which small glass spheres with a size of around 50 µm are embedded. For covering and coloring they can be covered with a colored film.
The incoming light beam is refracted when entering the glass ball, reflected from the ground and refracted again when exiting. In total, this creates a reflection in the original direction, so a large part of the light hits the light source again.
Reflector foils are available in different qualities, in ascending order:
- (Structure A): Reflective tape with integrated micro glass beads
- Micro glass beads are integrated into the carrier material, resulting in a flat reflector film without a honeycomb structure.
- (Structure B): Reflective tape with encapsulated micro glass beads
- Micro glass beads are encapsulated between a carrier material and a transparent cover material, usually recognizable by a honeycomb structure.
- (Setup C): Reflective tape based on microprisms
- Microprisms, which reflect the light back like a reflector , are embossed into the carrier material. Here, too, the cover material is supported by a honeycomb structure.
For use in traffic safety in Germany, the requirements for reflectivity are specified, among others, by the standards DIN EN 12899 and DIN 67520.
In addition, there are also simple reflector foils with an embossed prism structure. Their reflectivity is lower than that of the films with micro glass beads.
In addition to their reflectivity, reflector films also differ in their mechanical properties. Films with micro glass beads are generally more flexible than those with a prism structure.
Close-up of a reflector film
Macro shot of a reflector sheet
SEM image of a reflector film, magnification 15x
SEM image of a reflector film, magnification 200x
Areas of application
Reflector foil is most widely used as a safety device in road traffic. At night z. B. otherwise unlit objects visible to approaching drivers.
The Federal Republic of Germany has undertaken to apply the international ECE regulation 104 (Execution of retro-reflective markings to improve the visibility of heavy and long vehicles and their trailers). A “contour marking” is a series of strips that are attached in such a way that the contour of the vehicle is identified to the side (side marking) and to the rear (rear marking). This contour marking is usually attached to the vehicle using reflector foils.
Furthermore, numerous emergency vehicles used by the police, fire brigades, rescue services and breakdown services use reflector foils to improve visibility during night-time emergency trips.
Retroreflective products are also increasingly used in the private sector. Joggers use clack wristbands to be more visible when running in the dark. Self-adhesive reflective foils are enjoying growing popularity among parents who equip textiles and bags as well as children's bicycles and prams.
literature
- Fritz Winkler, Siegfried Rauch: Bicycle technology repair, construction, production. 10th edition, BVA Bielefelder Verlagsanstalt GmbH & Co. KG, Bielefeld, 1999, ISBN 3-87073-131-1
- Regulation No. 104 , Federal Ministry of Transport, Building and Urban Development (archived version, pdf)
See also
Individual evidence
- ↑ RSA-95: Retroreflective foils ( Memento of the original dated December 30, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed June 16, 2012.
