More Trivex Questions...

**Pete Hanlin** · 05-02-2002, 02:40 PM

Well, my Trivex lenses are here. They certainly "feel" impact resistant (they flex easily), are ground quite thin (1.0mm center thickness), and appear to be quite clear (free of any tinging or color).

Through no fault of the material (I assume this is a defect which occured at the lab), I notice a "blob" on the back of the lens. Looks like a particle trapped in a backside coating. Does Trivex have to be backside coated after surfacing? Based on the frame I've selected for these lenses, the defect will cut out anyway...

I plan to test the tintability of these lenses by turning them into sunglasses, which leads me to another question- can Trivex be mirror coated? If so, I assume I should let the coater know the lens is Trivex, but does it matter which manufacturer provided the lens (the lab ticket doesn't tell, but I think they are Hoyas)?

Also, doesn't Trivex come in finished form? I ordered the SV lenses from my lab thinking I'd get stock lenses, and the cost on the ticket is four times what stock poly costs (in fact, for this price I can purchase finished CR-39 with ARC). I therefore assume (from the price, the packaging, and the aforementioned backside defect) these lenses were surfaced. If Trivex isn't available in finished form, when is that release scheduled and any ideas on the pricing of the finished lens?

Thanks for the info. I'm going to go edge these puppies down and wear them clear for a day (just to see if I notice an improvement over my poly lenses, which I really wouldn't expect since I have a low power but we'll see).

RT · 05-02-2002, 06:02 PM

1. Trivex doesn't "have" to be backside coated, but every lab I know of does. Sounds like your lab shipped you a lens with a backside coating flaw. The fact of the matter is that since the factory front side coats come from the CR39 family of coats, we see significantly better coating quality on Phoenix than on poly. We reject up to 25% of certain poly lines due to specks and coating pits. We rarely reject Phoenix.

2. Its always a good idea to let your coating lab know what they're working with. There shouldn't be any coating issues that aren't present for other mid and high-index materials.

3. No, Trivex does not come in finished form yet from either HOYA or Younger. Haven't heard a schedule for it yet. Limited availability is obviously an issue. Gotta walk before you can run.

Don't be surprised if you DO see a difference between Trivex and poly, even at low powers. I'm only a -0.75 OU, and I can tell the difference. According to the OLA's spectral transmittance data, Trivex lenses reflect significantly less light than poly. That extra transmittance can work wonders.

Awaiting your next post on your edging experience...

**Jerry Thornhill** · 05-02-2002, 07:42 PM

Pete,

I backside coat all Trivex. They can be tinted. So far no problems with Mirrors or AR coatings.

Jerry

**harry a saake** · 05-02-2002, 08:20 PM

:finger: Since you mentioned it, as i have said in earlier posts, i would be rather careful in grinding these lenses down to 1.0 centers, because of the flexure problems that are just bound to happen. A .5 mm saved in the center is only a .5 saved on the edge, and you just cant see this.
......My gut feeling is some poor soul trying to make the worlds thinnest pair of safety glasses, or for that matter dress eyewear is going to do this and somewhere a patient is going to have the lens pop out with some serious complications when impacted.
.....I think this material is great and should be used for the optical benefits that you can derive from it, but we all need to forget this foolishness of seeing how thin we can grind it, unless of course you have millions in liability insurance and like to pay lawyers.

**Billy Brock** · 05-02-2002, 11:40 PM

hello mr. hanlin,

i've only been working with trivex for about 7 months and so far all ar & mirror coatings have done extremely well for me ----- have not had any adhesion issues as of this time

tint is another plus side of the product in my situation ----- lots of double & tri colors done here daily with very nice smooth results ----- sun tints have done extremely well in the fact they have been very very uniform in consistency ------ no bubbles on the coated surfaces from all the heat/chemical buildup ---- i was informed very quickly in the beginning as NOT to leave them in the tint and head out for lunch ! -------- color goes in nicely.... color does not come out ? ( i'm not sure if this is still the standard ? ? ? )

here is a photo showing trivex sun tint lens

regards,

B

**peyes** · 05-03-2002, 11:28 AM

The first pair of Trivex (Trilogy) we did was for myself. We inadvertently ended up with a .7 center...so I took the lenses to a work bench and pounding them with a hammer to see how much abuse they could take. I still haven't broke them and I wear them everyday.

**Pete Hanlin** · 05-03-2002, 02:54 PM

Nice looking pair of eyewear, Mr. Blake! I can see why everyone rages about your work. Are those Swarovsky (sp?) crystals?

Awaiting your next post on your edging experience...
Given my previous comments, I wasn't going to relay my edging experience- but since you brought it up...

Not having any technical data on how to process this material, I started out with low pressure on the edger and attempted to edge the first lens wet. The lens flexed so much that I lost the bevel along the temporal side! Thankfully, I punched a few extra tenths into our Santinelli for the first pass just in case something screwy happened. Even at the lowest pressure setting, the lens flexes so much it is difficult to edge.

Anyway, with subsequent cuts I placed a finger on the back of the lens and the bevel made it the whole way around the lens. On future orders, I will definitely order the lenses with at least 1.5mm centers! I edged the second lens dry.

I wore the lenses around for a while- and I honestly tried to notice a difference. If the rest of you can, that's great I suppose. Maybe I just have non-discriminating eyesight (I did check my VA and I can see 20/15 in both eyes using both my polys and the Trivex).

After 1/2 hour in the tinter, I got a decent green 2 shade. The BPI tint was a few weeks old, and when I finished the lenses in our grey tint, they did seem to take the dye at a good rate. I like my sunwear fairly dark (come visit me in Florida, and you'll understand why), and the lenses tinted quite dark for me.

To summarize my experience thus far, I would say my opinion has stayed pretty much the same (if that makes me seem pig-headed, so be it- but I was ready to change my mind about this product). It was nice to be able to clean the lenses with anything in the lab (acetone or alcohol), but they are just so freaking flexible I can't imagine making a polarized version (polarized poly causes enough problems due to flexure).

Trivex produces swarf, much like poly, but the swarf is much easier to remove from the edges of Trivex, and I'd guess Trivex would be easier to groove for a nylor mounting as well. I'll wear the lenses at the pool this weekend and send them off to Optovision for a mirror coating on Monday.

If the price comes down to that of CR and poly, and the lens becomes available in finished form, I imagine we might put it into our line-up to use with our Titan mountings. Till then, I can order either a polarized Rx lens or a CR lens with ARC for the same price, so I have a tough time understanding why I should order this stuff.

PS- They are certainly light! I didn't think I'd be able to feel a difference between the poly and Trivex, but they are a bit lighter... BTW, concerning the transmission, since the index is lower I would expect Trivex to reflect less light than poly...

**Billy Brock** · 05-03-2002, 03:11 PM

mr. hanlin,

thank you very much for the compliment, it really means a great deal coming from someone with your experience--------the stones in the trivex photo are Swarovski imported from Austria------ extremely nice quality in size especially when mounting that many stones side by side

Optiboard is really a fantastic forum that has allowed us to view your experience with a new product ------ thanks for sharing the feedback

B

**Pete Hanlin** · 05-03-2002, 05:32 PM

Well, on the drive home I have to admit that it did seem like these Trivex lenses made distant objects just a bit sharper than my poly polarized lenses...

Unfortunately, when I got home I looked at the edge of the lens and thought I saw a small shard of white towel remnant (we use lint free paper towels in the lab). I took my fingernail and tried to pick it out. Turns out it wasn't a piece of paper- it was a small area where the backside coating had peeled off, and scratching at it simply removed a larger chunck of the coating. Looks like most of the tint was contained in the scratch coat, because now there is a light scrape mark running along the bottom of the lens.

I am going to call my outside lab on Monday and see how they are coating these lenses. My guess is that this is not a defect in the Trivex, but in the coating (especially since I found that other "blob" in the coating when I inspected the lenses earlier). I'm sure this material presents its own processing challenges (poly took a while for me to figure out when I ran a surfacing lab). I suppose I'll just have to experiment on another pair in the future!

It is curious, however, that the material itself doesn't seem to have tinted nearly as much as the coating did- does Trivex actually tint, or is it like poly (the only thing that tints on poly is the hard coat)?

**sticklert** · 05-03-2002, 07:27 PM

Dear Pete,

In response to edging Trivex on a Stantinelli. I have noticed for those edgers that have an acrylic setting it works best.

In response to tinting: The SRC coating will tint faster than the material itself, however the Trivex material does indeed tint, just look at the beveled edge after tinting. you will notice a uniform tint unlike polycarb.

**Pete Hanlin** · 05-03-2002, 08:56 PM

Once again, thanks for the info- sticklert!

You're correct, although the lens is lighter where the coating has peeled away, I do notice that the bevels have tinted as you describe. I'm beginning to wonder if my outside lab might have used a backside coating meant for some other material- is there a specific coating they should be using?

Our Santinelli does have a setting for acrylic. It will be interesting to actually use it for a change!
:D

RT · 05-03-2002, 09:21 PM

Wow Pete. Tough week. At least it's Miller Time now.

I agree with your assessment on the backside coating failure. There's undoubtedly a correlation between the "blob" from your first post and the obvious adhesion failure. I'm unaware of any particular coating failure issues with Trilogy/Phoenix material, and our lab has been processing it for over a year.

Edging Trivex uncuts is occasionally problematic. Your best bet is to use your poly cycle with a dry rough and wet finish pass. We use the National Optronics 6E dry cut edger for all our Phoenix. It does a great job, and begs the question of swarf buildup. If you're using a conventional grinding edger, however, there are some considerations. Direction of rotation of the lens relative to the direction of rotation of the wheel is important (alas--I don't have my notes at home to remember which is right). If your edger goes in the wrong direction, you'll see massive swarf buildup. Other edgers produce startling amounts of dust--you'd swear the machine was on fire. We've heard more than one instance of people having difficulty edging Trivex; we've never heard of the type of coating failure you mention.

As far as the center thickness, HOYA recommends a center thickness of 1.3 mm to avoid the potential of cracking coatings in the edger chuck. But lens flex is also an issue, as you apparently experienced. To the best of my knowledge, HOLA labs all use the 1.3 mm CT, so it sounds like your lens is a Younger Trilogy. Based on our tests, I wouldn't recommend going down to 1.0, but as a previous post mentioned, impact resistance isn't the issue. Just because you CAN surface it to 1.0 doesn't mean you SHOULD.

In terms of the tint, the bulk of the color ends up in the backside coat. Unlike poly, however, the Phoenix/Trilogy substrate does absorb tint. In fact, if you tint it before putting down the backside coating, it absorbs the tint very rapidly. Getting an even tint on a non-backside coated lens is hard to do, however. Note that if you experience uneven tinting on a coated Phoenix/Trilogy lens, the problem is almost certainly a curing problem in the backside coat. Because the substrate accepts the tint, if there are differences in the thickness or hardness of the backside coat, tint will penetrate through the coat and reach the substrate unevenly, showing a color difference. The same uneven coat on a poly lens, however, doesn't produce a color difference, since the tint hits the substrate and stops.

RT
(HOYA lab guy, in case I haven't mentioned it lately)

**John R** · 05-04-2002, 12:56 AM

While looking for more information on these lenses i found this info on Youngers site and notice that their trilogy and hoya's phoenix lenses are not the same.
Could this lead to some interesting problems if trying to match lenses...

**Jim G** · 05-14-2002, 05:33 PM

I've been asleep too long...

Gad! You folks are good...and you've presented some great info to Pete.

Just a couple things to clarify. Trivex/Trilogy/Phoenix definitely needs a backside coating; the uncoated substrate is SIGNIFICANTLY SOFTER than CR-39, the standard. PPG did extensive testing of lab based backside coatings and found all perform to their standards. As RT pointed out, the execution at the lab is sometimes a little unsteady tho.

Re: AR and Mirror coatings. IF your lenses have a hard coat on both sides, your results with either will be significantly better than trying to coat a "naked" lens. Inasmuch as all Trivex lenses come with a factory applied front side SRC and (should) have a backside SRC, you should have no trouble.

I take a little exception with the comment that Trivex uses CR-39-like coatings rather than poly coatings and therefore will be better. Really no advantage BUT, it does come down to the execution. Periodically, manufacturers do have problems with coatings.

As many pointed out, there is no real corrolation between impact, thinness and viability. The thinner the lens, the more it will flex. Period.

To add to RT's comments on uneven tinting, poor surface cleanup or allowing the lens to sit overnight before cleanup before backside coating will also affect tinting. Youngers suggestion to use alcohol to clean thoroughly before tinting is ALWAYS a good idea.

**Billy Brock** · 05-24-2002, 11:29 AM

hello all,

just wanted to post an update after attending a PPG open forum last night ...... Jerry Dooley & Holly Cundieff are absolutely such gracious representatives & really make everyone feel very comfortable in discussing their in office experience with trivex

we walked away with a better understanding thanks to the sharing of ideas from each practice: marketing, coatings, strength, etc. were all covered ( and the food was great ! )

it's a great opportunity to attend if they are in your area as Jerry, Holly, the lens mfgr.& the lab are truly interested in LISTENING: good, bad or just indifferent, they want the real scoop !

hat's off to PPG, trivex mfgrs. & your local lab that host the forums !

B