I'm curious if A/R coating is formulated for specific lens index? (same manufacture and type) In other words, if one was to apply Alize A/R to a lens, would you get Alize formula number #1 for a 1.67 lens and Alize Formula #2 for a 1.74 lens?
I'm curious if A/R coating is formulated for specific lens index? (same manufacture and type) In other words, if one was to apply Alize A/R to a lens, would you get Alize formula number #1 for a 1.67 lens and Alize Formula #2 for a 1.74 lens?
Originally Posted by AustinEyewear
Yes. If you don't use this method, you get those rings (are they referred to as Newton rings or have I made that up?) which are the hallmarks of a bad AR.
Thanks Robert!
I don't think it happens in real life!
The medium size Labs have 1 AR machine that does 8-10 runs a day!
If they would separate all the indexes you will get your 1.74 with AR in 2 weeks.....
8-10 runs a day seems pretty low run for even a small lab? One B&M can easily require this.
Small lab cant afford the normal AR machine at all!
You will be surprised how many small labs outsource the AR!
Lenny is correct. Only some AR manufacturers separate lenses by index when applying the AR stack. As he noted, if you run separate production cycles for each combination of material and AR coating, you can run into a situation where you either have to hold up jobs waiting to get a full cycle (bad for service), or you have to run with a half-empty chamber (bad for costs).
What Robert is referring to is whether or not the hard coating underneath the actual AR stack is matched by index. Again, only some AR manufacturers do this.
RT
I'm getting confused here.
1.When you say small lab, what exactly does that mean? I was referencing a dedicated lab, that B&M's would farm out work to.
2.When you say AR manufacturers, are you referencing the chemical company or the lab (I'm assuming chemical company)? Do you know which manufacturers separate it by index?
Small is not large.......................
1. Small is not large. So it is either an in house operation or a small comapny you outsource to.
2. I assume AR manufacturers would be in the class of thin film applicators of which there are thousands of them world wide, employing just a few people to "Anwell Precision" in HongKong, employing 10,000.
So far I have not heard of anybody separating by index. The AR coating itself is so thin that it would not make a noticable difference.
A chemicals company would sell the products you coat with and the Thim Film company applies them to the substrate.
Steve could maybe say a word on this as he has been long in that business.
Just ran across this:
http://www.seikoeyewear.com/CE/CECourse.cfm?ceID=2AR coating of high index lenses involves different issues. The best coating has the same index as the lens. A typical lab batch for AR may include high index lenses varying from 1.53 to 1.74. Many manufacturers, including Seiko and Hoya, have the ability to index match the coatings to the lens. A benefit of index matching is that it eliminates the "rainbow reflections" that can be seen on the surface of lenses that are not index matched. By getting rid of these reflections, the lenses seem to "disappear" into the frame.
Different Quality Levels ? ..................................
Very interesting. Seiko and Hoya do match the index and the others do not. What now makes a makes a first quality product as everybody is swearing by on OB ?
Would that mean there are now more quality levels than the 2 so far standard " Best and not so good" ?
Yes.
The best coatings are done as described in the op, as I said.
The only effect of AR index matching is cosmetic. In case that index matching is not used, it doesn't mean that AR coating is bad - it means that residual color of AR will be shifted a little in visible spectrum.
Newton rings occur when index of hardocoating (lacquer) doesn't match to substrate's index.
Last edited by essegn; 07-03-2012 at 07:06 AM.
I read it that Seiko and Hoya are a few that do. Their words: "Many manufacturers, including Seiko and Hoya, have the ability to index match the coatings to the lens. "
Is the tint we see in some AR's caused by lack of index matching? Or is there just a slight tint, even when index matched?
I was under the impression that the A/R coating was applied more evenly when lenses of the same index were coated together. At least this is what was implied by my Hoya rep, for whom I have much respect. It could be marketing, it could be true. Who has the right answer?
"Strictly speaking, there are no enlightened beings; only enlightened activity." -Shunryu Suzuki
Shoot, even some mid-size labs outsource stuff. I think Saphire still has to be outsourced to Dallas. Or am I behind on the times?
"Strictly speaking, there are no enlightened beings; only enlightened activity." -Shunryu Suzuki
You are correct. Dallas is the only lab that is currently doing Sapphire.
My Rodenstock Rep too told me they too do Index Matching when Doing A/R on Rodenstock Lenses in Dubai & Believe me Rodenstock A/R is much Better then LotuTech of Carl Zeiss ( atleast what we use in Dubai )
you are behind! Precision is also doing Saphire
There are two seperate issues, the Hard Coat and the AR Stack. The AR stack will sometimes include a primer and now, usually a top coat. The hard coat is the real determining factor of the durability of the lens, and is more important to ABBE match to the material. If the hard coat is not ABBE matched, the AR will only heighten the effect of Birefringence (or as you say, Newton rings).
Although the the AR stack should be ABBE matched, the impact is less if its not. Most good AR labs will batch like lenses together for better results, and hard coat each material specifically for its ABBE value. This is one reason AR Costs so much, and your jobs take so long. You are waiting for an AR Rack to fill up. However, some materials like Poly and 1.67 are often run together through the stack to lower costs.
If you find one lab in the US who does EVERYTHING in house, let me know. Every lab, even big ones, outsource something.
Thanks for everyones input on this.
I have a follow on question: Is it possible to improve the lens effective Abbe value by applying A/R or other lens treatments to the "substrate"?
Last edited by AustinEyewear; 07-13-2012 at 01:24 PM. Reason: improve preciseness of question
No. The Abbe remains the same whatever layer (HC or AR) is applied.
If it was possible, you would know that for sure :)
I am pretty sure from my studing days that
if the square root of the material index = the refractive index of the MAR coating material then this gives the best antireflection properties
example magnesium flouride refractive index is closely matched to square root of 1.9 glass therefore giving best overall performance.
dont quote me on this it was over 15yrs ago I last remembered anyone asking........
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