Sol-gel as anti-reflective coat

[mazvaris79]

It appears that Sol-gel solution can be used as an antireflective coat (ARC) on lenses. Some literature suggests that the dipping method at room temperature can be used with sol-gel in order to give a lens an anti-reflective coat. It appears to be a very cost effective way of apply ARC as opposed to vacuum methods. However, I’ve not heard of any large scale application of this method with regard to lens coating. Is it that there are some guys using Sol-gel as an ARC or there is further research that needs to be done before it becomes accepted as an ARC method?

[HarryChiling]

It has been something I have been lookign at and interested in, sol-gel is being used in a in office sytem, I don't remember the naem, but I can tell you that some of the issues surounding sol-gel is shelf life of the solution (14 to 40 days) the problem is that if the solution is modified to be more stable particles start to form which could lead to defects int he coating. Also the adhesion and scratch resistace, sol-gel coatings still need to be thermlly cured to compact the layers, unfortunately the plastics we use for lenses would not hold up to the optimal temperatures needed to fully cure the coatings. Then the thickness, if the layers are to meet exacting thicknesses a dipping process where the lens is dipped at a constant rate and removed from the solution at a constant rate has to be employed, one way to help with this is to dip the lens multiple times into a diluted solution, but the dilution of the solution with alcohols will again lead to poor shelf life and this still means multiple steps of dipping and thermal curing, which leaves more chances in the process to introduce defects or particles into the coating.

The idea is a great one, but the process has to be refined and I don't think that it would be the easiest way of coating a lens, but it does show the most promise for an in office system, so I continue to watch this technique.

[Chris Ryser]

http://www.chemat.com/9.tpl?cart=%5Bcart%5D

[DragonLensmanWV]

Is that the AR that Wal-Mart used to use on their ODC progressives?

[HarryChiling]

Sol-gel without equipment in the office and a good understanding is no better than a vacuum deposition process without the equipment and understanding, you could get a bell jar vacuum, hot plate, and crucible and get an in office AR with just as much time and energy as you would with a sol-gel process. With AR I just don't see any worthwhile shortcuts.

[jameselex]

we are using the sol-gel a/r coating, and it seems acceptable, the good thing about it is you never have to worry about coating cracking;but the coating is not so hard. the process is time consuming.

[HarryChiling]

What system do you use?

[mazvaris79]

This sounds quiet cool, at least there is someone using sol-gel. As HarryChiling has said – can you please elaborate on the type of system you guys? I quote (jameselex) “seems acceptable” – how confident are you guys with this system – or has there been any issues regarding quality from yours customers?