Backside a/r and polaroid lenses

**specs4you** · 06-20-2010, 12:43 AM

This is such a bad brain fart I am having. What is the technical reasoning for only backside coating with a/r a polarized lens? I know it is something about allowing light in etc.. We brainstormed this before and I got off this site for awile and my brain went dead because I am not using a lot of technical talk in my new job. Please refresh me....and my spiel to the customers.

Also, my manager thinks scratch coat in already in CR39 polaroid lenses and not to sell it. I was always told that while there is a form of hard coat in most Cr39 lenses
you still need to do it to have a warranty. Labs have always told me to sell it, that this is the only guarantee. Ask a 100 people get 100 diff. answers huh?

I know it is trivia but sometimes factoids just fall out of my brain at this place.....I am not using enough of my knowledge.

You genus types that are fresh brained can help an old fart right?

**Jubilee** · 06-20-2010, 09:12 AM

I was always told that the CR-39 polar has SRC already applied. However, there are some labs that do make you order/pay for it in order to have the warranty it provides. Some insurances (like Davis) are also requiring this as a way to contain costs.

The reason why you want a backside AR on a sunglass is due to the backside reflections. Have you ever had one w/o and put the sunglass on and see your reflection in the back of the lens? OR looked at that shiny black table top and notice the reflections? Since less light is getting through the sunglass, more light is being bounced back and you are getting more reflection. The backside ARC allows the light to go through, to keep the vision comfortable and clean.

**Crazy-bout-Optics** · 06-20-2010, 09:31 PM

As far as not putting them on the front side:

I ordered in for a PT a Polarized Pal and added A/R, forgetting to specify "Backside Only". When they came in the Lab couldn't find any of the Pal markings and reordered lenses. Same thing with the second set, couldn't find them either. When I came back in to work and saw the two sets of lenses I looked myself and couldn't see the markings. Granted I was able to determine where the marking should have been and got them made. Pt could see perfectly. But if she comes back and we have to troubleshoot the pair we would need to re-order them in as backside only. **** Anyone else experience this???

I believe another reason not to A/R the front side is with sun you are trying to block out light and A/R allows more visible light in.

~Crazy

**edKENdance** · 06-20-2010, 10:14 PM

Deja Vu! I like AR on the front.

**specs4you** · 06-21-2010, 12:03 AM

Originally Posted by Crazy-bout-Optics

As far as not putting them on the front side:

I ordered in for a PT a Polarized Pal and added A/R, forgetting to specify "Backside Only". When they came in the Lab couldn't find any of the Pal marking and reordered lenses. Same thing with the second set, couldn't fin them either. When I came back in to work and saw the two sets of lenses I looked myself and couldn't see the markings. Granted I was able to determine where the marking should have been and got them made. Pt could see perfectly. But if she comes back and we have to troubleshoot the pair we would need to re-order them in as backside only. **** Anyone else experience this???

I believe another reason not to A/R the front side is with sun you are trying to block out light and A/R allows more visible light in.

~Crazy

That's what I was trying to recollect, the more simple it is the harder my recall is.
Honestly I am beginning to worry about myself. Thank you. Can I put you on retainer for memory optics? lol

**Crazy-bout-Optics** · 06-21-2010, 12:38 AM

Sounds like a plan ;-)

hey! You live in La La Land too! We must be neighbors !!

**uncut** · 06-21-2010, 05:55 AM

Don't forget the spectrum! On the other side of the visible spectrum(we tend to emphasise the UV) is the infrared(heat) which causes discomfort in warmer climates. Leaving out the AR on the front assists reflectance, which reduces infrared absorb. The more reflective, the cooler the eye area feels and less irritated from heat.

**DragonLensmanWV** · 06-21-2010, 06:06 AM

I always use it on both sides. It can't let much more light in (maybe 3%) and the polarizing layer will do the rest of the work, and they'll be easier to clean. Of course, I think a mirror over the polarized is best.

**MasterCrafter** · 06-21-2010, 01:17 PM

The main benifit of Backside AR is the reflections. People complain about seeing the reflection of thier own eyes on the back of the lens. Also alot of people want the matte finnish of not having the AR on the front surface. Some people like this look better than having AR on both sides with sunglasses.

Also scratch coating does not always come on polarized lenses. Younger Optics for instance has uncoated and coated products. So you must specify to the lab what you want.