Newsletter issued in August 2017
How to Load Lenses for Coating, etc.
1. How to load lenses on a planet for coating
To achieve high-quality AR coating on lenses, it is important to mount lenses in a planet properly. In fact, lenses are often mounted incorrectly, as shown in the first diagram below: the lenses are laid flat at various radial positions of a planet. This results in thickness distributions on the lens surfaces to be quite uneven and, more detrimentally, non-concentric, as shown in the first thickness map below.
It is easy to obtain a much better outcome by mounting the lenses with proper tilting angles and displacements in the z-direction, as shown in the second diagram below. Such an adjustment can yield thickness distributions that are nearly identical for lenses located at different radius and are all concentric, as shown in the second thickness map below.
The above-described situation arises in all modes of PVD coating, whether it is sputtering or evaporation, simple rotation or planetary rotation, whether correction masks are employed, AND it arises in systems that are optimized perfectly for flat substrates. This method of titling and re-positioning the lenses is one example of the technique of "Terracing". To determine how to set the appropriate tilting angles and displacements for a particular job, one can adopt the trial-and-error method or employ a numerical modeling tool. The later approach proves far more effective. The PVD modeling software, V-Grade 5 or V-Grade 5S, produced by Tin Model LLC is a convenient tool for the purpose. To view examples of achieving best results of coating lenses please visit Case Studies in Tin Model website: http://www.tinmodel.com/Case-Studies.html .
2. Tin Model issues update for V-Grade 5 series products
On July 26, Tin Model LLC issued an update to its V-Grade 5 and V-Grade 5S products. The update fixes a bug in the saving and recalling of correction masks. If you are a current user of V-Grade 5 or V-Grade 5S we encourage you to contact us for the update.
© 2017 Tin Model LLC, 2285 Massachusetts Ave.
Cambridge, Massachusetts 02140, U.S.A.