Pete, Crizal question...

[karen]

Hi Pete! There is a pull out add in Eyecare Business about Hoya Super Hi Vision. It states 10.94 on the Bayer abrasion scale, 110 degree water drop contact angle and les that 0.5% reflectance I was wondering how Alize compares. Can you give me the scoop??
thanks!

[chip anderson]

Karen:

Don't know the answer to your question, but I can tell you that the Crizal product will hold up much better against the coating wearing off. I have never had to eat a Crizal coating, but I have had to eat Hoya although I have used the Crizal 100 times as much.

Chip

[Pete Hanlin]

The contact angle is going to be slightly steeper on Crizal than on Hoya Hi-Vision (which means it is slightly more hydrophobic).

Regarding "scratch resistance," the Bayer abrasion score is only one measure of a coating's quality. Adhesion, impact resistance, flexibility, etc., all contribute to the overall picture.

For example, do you remember Ford cars in the 80's? They went to the molded bumper that was color matched to the car. The paint was really really hard. Unfortunately, it was much more brittle than the rubber/vinyl underneath, and it would peel away (the underlying material was yellow- and you can see many old Mustangs and TBirds with yellow bumpers these days).

A good AR stack is going to be one that is scratch resistant- but also resistant to flexure, peeling, and contamination. Right now, nothing performs better than Crizal Alize for overall durability (and availability).

[karen]

Thanks Pete-since I have to compete against it in the accounts that did not switch over when I left Hoya it is good to know what I am up against, marketing mumbo jumbo aside.

Chip- are you talking about Super Hi Vision or just regular Hi Vision? I had a few pairs of Hi Vision myself and did not have any problems but since I have about 10 pairs of glasses in my current Rx, I never wore one all the time and don't know how it would stand up to daily wear.

[chip anderson]

Karen:

If you use a lensometer and a slit-lamp a lot, they will hold up about 2 months no matter what you do to cushion the eye pieces.

Chip

[Chris Ryser]

chip anderson said:
Karen:

If you use a lensometer and a slit-lamp a lot, they will hold up about 2 months no matter what you do to cushion the eye pieces.

Chip

Whatever lensometer you are using you still touch the surface and may abuse it.

All of the AR coating companies are using the same material which is called SIO2 for AR coatings.

They all use a vacuum coating machine , some of them smaller and some of them bigger.

"So it boils down to that you are getting the same coating whatever the name of the coating or the name of the manufacturer"

However, as Pete has explained, the success of an AR coating is the layer (hard coat) between the substrate (lens) and the AR coating. If the hard coat has the ability to provide maximum adherance and hold the applied SIO2 layer in place a longer period of time than one made by another company you'r the winner until something even better comes along.

By the way all this problem with hard coats does not exist on glass lenses where the AR coat adheres without any extra treatment.

[karen]

[b][i]C

"So it boils down to that you are getting the same coating whatever the name of the coating or the name of the manufacturer"

Chris-do you think "substrate matching" makes any difference? particularly in reference to SRC??

[Chris Ryser]

karen said:
Chris-do you think "substrate matching" makes any difference? particularly in reference to SRC??

karen,

The substrate is the lens in our case. Today there are many hard coats on the market and it takes some doing to find the right one that will do the double job of holding on to the lens. Also the different lens materials do not all react the same way to a hard coat.

The hard coat beneath the AR coating does actually not have a scratch resistant function, but is more a media of adherance for the AR coating

You will have to match the lens with hard coating material that will adhere to the lens and provide a good adhesion to the AR coating. This hard coating could an second rate coating for a regular lens but it does the trick as an in between layer.

[Henry]

Karen,

According the data shown in Teflon marketing materials, Crizal AR rates Bayer ratio of 4. Surely, Bayer ratio is one of AR coating performance parameters. Flexibility and adhesion are other important performance. Since all vacuum processed AR are made of brittle ceramics such as SiO2 (silica) and ceramics are not compatible with plastics, these AR coatings will crazes and peeling off unless being taken very carefully.

[karen]

Chris Ryser said:
karen,

The substrate is the lens in our case. Today there are many hard coats on the market and it takes some doing to find the right one that will do the double job of holding on to the lens. Also the different lens materials do not all react the same way to a hard coat.

So can you match the SRC and AR to each material for better adhesion? (hypothetically of course;) -do you see where I am going here?)

[Chris Ryser]

karen said:
So can you match the SRC and AR to each material for better adhesion? (hypothetically of course;) -do you see where I am going here?)

Pete from Essilor claims tha their Crizal lens is presntly the best on the market due to good research and a good hard coat and in between adhesive on plastic lenses.

Many of the optiboard members swear that mentioned brand is the best.

If Essilor succeded to come up with good product, it is also possiblefor any other supplier or coater to do the same if they invest the time to find better products than they are using presently

However it is a fact that in the optical world many, or most prfessionals,, on both sides, are very conservative and not always open to new ideas.

[Pete Hanlin]

There are several characteristics that combine to make Crizal an exceptional product. One of them, without doubt, is the hardcoating. Mithril is a wonderful hard coat that was engineered to work with the AR stack.

Regarding the tailoring of hardcoats... in general, polycarbonate and CR-39 are polar opposites when it comes to adhesion. In other words, if a coating sticks really well to one, it will probably not stick well to the other. Most high indices are similar to CR-39 regarding adhesion characteristics.

Another characteristic- which is perhaps most important- is the integration of the SRC and ARC. With Crizal, you start at the substrate. Its like painting a wood surface- you will have better adhesion if you sand straight down to bare wood and apply a primer- then apply the paint. If you just paint on top of existing paint (e.g., AR on top of an existing hardcoat), your performance is limited by the existing layer of coating.

Before a category of lenses is "Crizal-able," Essilor conducts tests to make sure that a.) the lens can be procured in an uncoated form, or b.) the existing hardcoating can be reliably and consistently stripped.

Finally, once again, Bayer values are only a small part of the puzzle. A coating that won't scratch is worthless if it peels off. Also, impact resistance and other factors come into play.

Could another company develop an integrated coating with excellent properties? Of course, Crizal has been on the market for over 7 years now- even if other companies didn't know how to do it before, they should have been able to learn by watching. However, another important thing to remember is a.) Essilor has built a lot of experience over the years, b.) Essilor devotes a ton of money into coating R&D, and c.) Essilor has the resources and partners necessary to make the product available and make the consumer aware of it.

All that to say, being an innovator and leader in a field has its advantages- for all involved.

[Henry]

Peter,

Does Crizal AR plus Mithril Hard Coat yield the same performance over different lens substrates (CR-39, Poly, High Index) ?

Henry

[karen]

Pete Hanlin said: Mithril is a wonderful hard coat that was engineered to work with the AR stack.
.

Do they really call it that?? How LOTR!

[Chris Ryser]

Henry said:


Does Crizal AR plus Mithril Hard Coat yield the same performance over different lens substrates (CR-39, Poly, High Index) ?

Henry

I looked up the name Mithril and came up with the following:

This introduction to the Mithril programming language and development environment must serve many purposes, and needs more than one page at this top level (pages: 1 2 A B C F N). Not only does Mithril need an introduction, but so does this section of the web site about Mithril.

[Texas Ranger]

Pete, I guess that my understanding of Crizal is different. I have used about 90% AR for several years, and Crizal for the past 5 or 6 years. I believe and our clients know that people see better with AR lenses. durabilty and cleaning were always at issue. the Crizal took care of the durability factor, and the Alize' takes care of the cleaning factor. back to my understanding of Crizal; a) the subtrate has all "hardcoat" removed from it so that it is more porous, prior to the vacuum process, and that zerconium oxide is used that is absorbed into the substrate. so the big difference is that it is not a "laminate" process, so it does not get brittle and crack and craze, since it is "in" the lens. Now, this is how it was explained to me 6 years ago, and in that time, I have never seen a "delaminated" Crizal lens, and they have gladly replaced all scratched lenses. So when we discuss AR with clients, we simply say that one AR process is like "wall paper", it can peel off, etc. whereas the Crizal is like Latex paint, it soaks into the lens, physically changes the lens structure, therefore can never be "stripped and recoated", making it as different to the original plastic lens as if were another material. It can not be tinted over, just like glass. And this is true.

[Chris Ryser]

Texas Ranger said:
..................................... therefore can never be "stripped and recoated", making it as different to the original plastic lens as if were another material. It can not be tinted over, just like glass. And this is true.

As this falls into my department of wisdom I am taking the liberty to comment on the last 2 sentences of Texas Rangers post.

I have been in the AR coating stripping business since 1984 and can certtify that ALL AR coatings can be removed within 5 seconds with one of my products at room temperature in any in house environment.

Once the coating is removed the surface can be neutralized of any acid residues and can then be recoated.

Also the hard coating underneath the AR layer can be easily removed if it is slightly scatched andf you might have a totally un scratched clean lens after that procedure.

The lens can then be tinted without any problem.

Conclusion;

If you have a patient that is buying a new pair of glasses because the old ones are scratched or whatever, you can strip them and tint them as a pair of sunglasses

[Chris Ryser]

It is not computer language..............but I found another one that could be closer to hardness ..................................

"Return to Kinlo Strongarm in Kaladim. Give him the Hammer of the Ancients. This will cause Usback the Old to spawn. Usback the Old will give you a Small Bit of Mithril Ore. Give Usback the Old An Ancient Sword to receive the new and improved Refined Ancient Sword. Give the Small Bit of Mithiril Ore to Kinlo Strongarm to receive the Refined Mithiril Blade."

[Peter Z]

Crizal is applied to lenses the same way most other A/R coatings are applied. In the case of Crizal the lens is hardcoated using a nano-composite thermal cure hardcoat with a primer applied first and then the topcoat or hardcoat. The A/R stack is applied in a vacuum chamber on top of the hardcoat and then the hydrophobic coating is applied after that. For Crizal both the ALIZE or standard hydrophobic is applied in the vacuum chamber after the application of the A/R coating.

While the CRIZAL process is good, that alone does not guarantee you a problem free job. The application of coatings like hardcoats and A/R coatings require a team who are trained and experieced in the application of organic coatings like the hardcoats and thin film people who understand the application of thin film coatings in vacuum. You can have 3 labs who have Zeiss coating equipment and receive 3 different products form them. Some maybe good and others poor. Threads read here prove this point. Some Claim Zeiss coatings are good while others claim the fail in the field. The difference between success or failure in many cases is not the process type or equipment it is HOW THE PROCESS GETS IMPLEMENTED.

The application of coatings is a very involved science where the difference between success or failure is in the hands of the ones who run the equipment and execute the process. Equipment maintenance and adherence to good manufacturing procedures is a must to produce high quality coatings.

All coating manufactures experience failures. The goal is to keep the failures to a very low % of the work produced. The Keys to success with any coating is the following:

1. Make sure you are using a premium A/R which includes the use of a thermal hardcoat OF THE SAME TYPE ON BOTH THE FRONT AND BACK SIDE OF THE LENS.

2. Make sure the coating manufacturing has a consistent and repeatable process. Is the coating color the same day to day and batch to batch? Is the uniformity of the coating (Color of the reflectance) the same across the lens and carried out to the edge? Do you get returns from customers within 12 months? What many think are coating scratches are really coating failures. If you send lense in for recoating and the scratches disappear then the problem was an adhesion problem not a scratch problem. A good A/R coating will not scratch easily when placed on a good thermal cure hardcoat.

3.) Make sure the coating manufacturer is testing the process daily to make sure that problems are caught daily before 1000's of pairs are produced and put into customers hands. Good coating companies test lenses from every batch before releasing that batch to be sent out or glazed. This is very important. You can have a bad batch of coatings yet the color looks Ok. Companies like Essilor and others test every batch before it gets shipped out. Make sure your coating supplier does the same.

[Ray Parent]

The Science of Middle-earth -- Making Mithril
http://greenbooks.theonering.net/gue...103003_02.html

That link is probably the best background you can get on the origins of Mithril. Tolkiens definition of Mithril was essentially of a strong, flexible metal.

[karen]

Ray Parent said:
The Science of Middle-earth -- Making Mithril
http://greenbooks.theonering.net/gue...103003_02.html

That link is probably the best background you can get on the origins of Mithril. Tolkiens definition of Mithril was essentially of a strong, flexible metal.

That's why I said LOTR (Lord of The Rings) I thought maybe Pete was making a joke (were you?) Bilbo had an undershirt of Mithril that he got on his adventure in the Hobbit that he passed on to Frodo. If I recall it saved him from a worse injury when he was stabbed by a Nazgul. It is very strong and very lightweight -didn't look at the website but is either elven or dwarf made I believe. I have been a Tolkien geek since 5th grade when my dad brought home the books for me to read. Hope the rumors of a Hobbit movie are true!

[Chris Ryser]

karen said:
That's why I said LOTR (Lord of The Rings) I thought maybe Pete was making a joke (were you?) .....................................................It is very strong and very lightweight -didn't look at the website but is either elven or dwarf made I believe. ....................

So now you all know that if there would have been no LOTR (see above) there would be NO Mithril

and

Essilor would have NO improved Crizal and you would have to sell another AR coating