Through a couple of recent conversations with blog readers and patients, it’s become clear that many do not fully appreciate just how complicated anti-reflective treatments are to manufacture. I hope to dispel some of this misconception today…
More than a Dip!
Since so much of lens treatments can be cone by dipping a lens in a hot vat of some near-boiling liquid, it’s easy to understand how you might think that’s all there is to an anti-reflective coating. But, believe it or not, even the most inexpensive (read: easily scratched) coatings require a multi-stage process to apply to a lens.
This video showing the application of Crizal Avance will give you a little window into the process of applying a no glare treatment to lenses.
Lenses need to enter a dust free room similar to those in the manufacture of microprocessors. Then they must go through a multi-stage bath system to remove any and all dust, residue, oils, or items with the potential of producing blemishes on the lens. Once the lenses are fully cleaned, then they are placed in a tray inside a vacuum chamber and blasted with various ionic elements so that they can adhere fully to the lens, and provide both the light bending action to minimize reflection, as well as provide the scratch, oil, and water resistance layers. For the best coatings this is 9-15 layers to complete this process.
Once the lenses are removed from the chamber, then they are given a visual inspection to make sure the coating adhered properly. Any speck of dust left on the lens before entering the chamber will ruin the coating, creating a drip point from which the coating cannot adhere properly.
There are many dozen variations on anti-reflective manufacturing, but all of them, even the most inexpensive simple solution, requires an elaborate process of cleaning, dust-free rooms, and vacuum chambers to apply the coating. In great part, this helps to explain just why anti-reflective coatings cost so much.