Hydrophobic AR Coatings...

[Pete Hanlin]

This is related to another thread I have on the General Discussion Forum concerning what I can use to make reference marks on AR coated lenses.

I notice that most ink markers "bead up" when applied to AR coated lenses. I am assuming this is because the hydrophobic coating repels the ink. However, on SOLA's UTMC product, the marker seems to write just fine.

What is the difference in the hydrophobic coatings? Is there anyone still employed at SOLA who knows? (Does SOLA still employ anyone in general ;) ?)

Pete

[Clive Noble]

Hi Pete,

Just out of interest, I've noticed when marking coated lenses that if you blow on the lens as you are applying the 'ink' it tends to hold much better. Not like uncoated CR, but certainly better than the 'beading'

It certainly holds during edging.

[Pete Hanlin]

I'll have to try that! I was just amazed the other day when I was marking a lens that I was preparing for a Marchon Airlock frame. The marker (a thin Sharpie) wrote as clear as a bell on the lens.

For a moment, I thought "Hey, I thought this lens was AR coated... must not be afterall." Then I checked and, sure enough, the lens had an AR. After asking where the lens came from, I discovered it was a SOLA UTMC lens. The difference in markability is astounding, and naturally my retentive mind just has to know why!

I will try blowing on the other types of lenses however (we use Pentax, Crizal, and Reflection Free as other AR providers in our shop besides the UTMC).

Pete

[Jim G]

Steve can give you more details but I seem to remember that SOLA said the UTMC process had hydrophobic qualities without the use of a hydrophobic coating. That would account for your experience.

[Steve Machol]

That's right, UTMC was designed to have 'easy-to-clean' properties without the use of a hydrophobic top coating. This is true of all UTMC sold in the U.S. and Canada except for ViZio 1.66 which is manufactured in Japan.

[unclebucktoyou]

Well Peter the design of the UTMC is utilizing a coating that SOLA describes as having properties that eliminate static energy accumulating on the surface of the lens and resulting in a lens that will infact attract less air impurities, ie dust. However this results in a lens that is quite porous and that will stain much much easier than a complete coating featuring an integrated hydrophobic coating. You will also notice that cleaning a UTMC will "feel" much more rough than a lens with hydrophobic properties. This is why you can write on a UTMC lens as the lens actually is absorbing some of the ink. So the choice is, easy to clean (hydrophobic) or less static charge (UTMC)

your uncle

[Pete Hanlin]

Well, given my experience with my own UTMC lenses (ViZio, pre LASIK ;) ), I'll take "less static charge!" PLUS, I can easily mark them (which naturally biases me in my role of occasional lab rat).

However, while we are on the subject, let me say that I have been astounded with the Crizal lenses I've seen thus far! These lenses do actually seem to be "tougher" than any other ARC I've seen. Its nice to be able to work with an ARC lens in the lab without breathing lightly every time you pass within two feet!

Thanks for the info on why UTMC marks so easily. I have now fulfilled my "learn something new every day" requirement... :) I also think I will begin ordering the UTMC product for our Titan and Airlock jobs. One question, however. If the UTMC actually absorbs the ink, does this mean I run a risk of having permanent "shadows" on the lens if I do not expediently remove the markings after processing?

Thanks again, and btw, please never call me PETER! :D

Pete

[unclebucktoyou]

Hi Pete,

Yes you can see shadowing - it will come out but you will have to work at it. One thing to note - the Airlock mounting system really attacahes quite well to the lens with their plastic bushing system. This system puts some pressure on the lens and as such a polycarbonate lens is highly recommended.

uncle

[Pete Hanlin]

To anyone who happens upon this thread, I just wanted to "amen" that last comment! I have personally cracked at least seven high index, Crizal coated PAL lenses trying to drill them for Airlock frames. Since the last pair, I have mandated that we only sell polycarb in Airlocks... nary a problem since, and I've drilled about a dozen pairs!

Pete

[sticklert]

Hey Pete I work for a Whosale Lab (Hoya owned). But rather than subject your patients to the horrible optics and Rx limitations of Polycarb why not use the new Trivex material (Phoenix or Trilogy) it is very comparable in price and offers far better optics while still having a very high tensile strength. It has been very successful here in the NW.

:cheers: