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Plastic lenses have become quite popular due to unbreakability and
lighter weight. Generally plastic lenses are required to be coated
to impart hardness and increase scratch resistance. After making
the plastic lenses harder, they are also coated to prevent reflection
and make them anti-glaring.
Fraunhofer Institute of Applied Optics and Precision
Engineering has carried out further development in which different
materials are coated by a single process to impart hardness as well
as anti-glaring characteristics to the plastic lenses. When different
materials used to make plastic lenses were evaluated by this new
process, it was found that cycloolefin plastics (TOPAS of Ticona
etc.) gave the best results. The new coating has an excellent bonding
with cycloolefin plastics. Besides, the inherent temperature resistance
of cycloolefin plastics would make the lens to withstand a very
wide temperature range from as low as -35ºC to as high as 100ºC.
This new coating could open up a new opportunity for cycloolefin
plastics not only for the conventional lenses but for camera, endoscopes
amd microscope lenses. In fact, cycloolefin lenses have 98% optical
transmission as compared to 92% of the conventional plastic lenses.
High cost of cycloolefin plastics however, could pose some problems
for the normal plastic lenses but could find usage in the high value
added applications like camera, endoscopes etc.
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