<span style="font-family: Arial; color: #3f84b4; font-size: large;"]MRC<span style="font-family: Arial; font-size: medium;"]-Coating

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<span style="font-family: Arial; color: #3f84b4; font-size: large;"]M<span style="font-family: Arial; font-size: medium;"]ulti<span style="font-family: Arial; color: #3f84b4; font-size: large;"] R<span style="font-family: Arial; font-size: medium;"]esistant<span style="font-family: Arial; color: #3f84b4; font-size: large;"] C[i]<span style="font-family: Arial; font-size: medium;"]oating [url="http://www.schneiderkreuznach.de/knowhow/mrc.htm][/url][/i]

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<p align="left"]<span style="font-size: 10pt; font-family: Arial;"]The

<span style="font-family: Arial; color: #3f84b4; font-size: x-small;"]acronym "MRC"<span style="font-size: 10pt; font-family: Arial;"]
stands for "<span style="font-family: Arial; color: #3f84b4; font-size: x-small;"]M<span style="font-size: 10pt; font-family: Arial;"]ulti

<span style="font-family: Arial; color: #3f84b4; font-size: x-small;"]R<span style="font-size: 10pt; font-family: Arial;"]esistant
<span style="font-family: Arial; color: #3f84b4; font-size: x-small;"]C<span style="font-size: 10pt; font-family: Arial;"]oating". The lens coating
normally used for B+W photographic filters and certain SCHNEIDER
lenses is resistant in several respects: for one thing, to the
influence of dust and moisture, for another, it offers a
significantly higher resistance to mechanical scratches on the
surface of the lens. The cleaning of filters with this hard,
water-repellant system of coatings has become altogether
considerably easier.
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<span style="font-size: 10pt; font-family: Arial;"]The illustration
at the right shows a prepared filter which has been moistened; the
one half is coated with the traditional MC coating, and the other
half with the new coating design MRC. It is quite evident: the water
droplets do not stick on the MRC coating (at the right).<span style="font-family: Arial;"]








<span style="font-size: 10pt; font-family: Arial;"]The
broad-band anti-reflection coating MRC is produced by a
plasma-supported condensation-deposit
process. In this process, the accelerated inert-gas ions
condense the material deposited as very compact and resistant layers.
The uppermost layer consists of fluorinated Siloxan. Each side of
the filter consists of a system of eight interference layers, i.e.,
sixteen layers per filter in all, with a total thickness of about
250 nm! This corresponds to a thickness of &frac14; &micro;m! The uppermost
layer has low surface energy, which is to say low surface tension;
this results in a high wetting angle of contact, e.g., against water,
of about 120&deg;. This phenomenon is similar to a drop of mercury on a
piece of glass. It is in this low surface tension that the physical
secret lies, namely, why the new MRC coating considerably inhibits
the adhesion of moisture.
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