GRINIFIL
GRINIFIL was the brand name of polymer optical fibers ( called plastic light guides in the GDR ). The light guides were first produced from 1974 and were intended for signaling or lighting purposes over short distances of a few meters.
Manufacturing
The technological basis for the production of GRINIFIL was researched in the VEB Carl Zeiss Jena and in the VEB Chemiefaserkombinat Schwarza . GRINIFIL conductors were produced from optical fibers based on synthetic high polymers in a melt spinning process. The light guide threads were brought together in a core-sheath arrangement. The material of the core had a higher refractive index than the layer of the cladding. The diameter of the individual light filament was 0.25 mm. The thread bundle was surrounded by a protective sheath made of opaque polyethylene . The product was offered as light guide threads or as light guide cables (Lk). The Lk were manufactured in 1974 in four sizes, the effective diameter from 1.25 mm (outer diameter 2.1 mm) to 2.75 mm (outer diameter 3.7 mm) increasing in steps of 0.5 mm. GRINIFIL was produced in the VEB Chemiefaserkombinat Schwarza in Rudolstadt -Schwarza, where the parent company was.
Working principle and properties
The light rays which enter at a certain angle to the longitudinal axis of the core light guide are reflected at the interfaces of the core light guide and the cladding and transported in a kind of zigzag path in the core light guide. The transport quality of the light intensity is also determined by the quality of the end faces of the core light guide. Further light losses occur as a result of absorption in the core light guide in the individual threads and as a result of reflection on the end faces. The light intensity or signal fidelity should be sufficient up to a cable length of 12 meters.
The cable could be laid in different directions, whereby the bending radius of the cable should be at least three to five times the respective cable diameter. If the cable is to be used in a vibrating environment or in constant motion, the bending radius of the laying should be ten times the cable diameter. The cables worked in an ambient temperature of −5 to +70 degrees Celsius without major interference. If there was no mechanical stress on the cable during use, a lower ambient temperature was also permissible. The working temperature should only briefly exceed +70 degrees Celsius.
Since GRINIFIL light cables emit a cold light, use in an explosive environment was permitted.
Applications
The light cables should guarantee safe light transport if the properties of the cable and the conditions of installation are observed. Therefore, an application for the purpose of controlling and monitoring equipment and production facilities was suitable. Signals from fault reports and other information could also be transmitted safely to the greatest possible extent without being susceptible to interference. Therefore the light cables could be used in the following branches:
- for brake light control in vehicle construction
- for dial illumination in radio and television facilities
- at assembly tables in the production of printed circuit boards in electrical engineering
- as reflex sensors in control engineering
- in devices for scientific purposes
- in electronic data processing equipment
Individual evidence
- ↑ K. Kühlmann: Flexible plastic light guides GRINIFIL , in: Chemische Technik, Volume 26, Issue 3, 1974, p. 182
- ↑ Leipziger Messeamt : Who delivers what? Reference source for purchasing in the German Democratic Republic , Leipzig 1976