# Optical Forums > General Optics and Eyecare Discussion Forum >  EMI Coating

## Jacqui

HELP !!  My Oriental lens supplier keeps talking about EMI coating, what is it?? Looks to me just like a good AR. Is there a difference??

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## For-Life

> HELP !! My Oriental lens supplier keeps talking about EMI coating, what is it?? Looks to me just like a good AR. Is there a difference??


That is the EMI HMC right?

Here I get OSA Lites HMC, so I think they are the same (Korean).  From my understanding the company is owned by Essilor, and so far I have had not troubles with it.  I am still testing it out though.

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## Peter Z

EMI stands for Electro Magnetic Interference which is designed to reduce radation from Computer screens and other source of EMI.  Also acts like an Anti-Static Coating as well.   Many imported lenses with A/R have this feature.

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## Jacqui

Why don't the American coatings have it?? or if they do why not say so??

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## Clive Noble

We started getting this EMI coating here in Israel about 2 years ago.
It was fanfared in with much honour by the importer.

The lens rep came with some sample lenses and some sort of electronic meter scaled from 0 to 100   He placed the head of the meter one inch from an electrical plug outlet and the meter shot up to 100.   He then took an EMI coated lens and placed it between the plug and the meter and sure enough, this special EMI lens reduced the reading to a low number.

Very impressive I thought,  so I gave him my (then) 2 year old Panamic Trans 1.56 with Crizal and guess what?????  The meter reading went down to the same low number   WOW!  I've been having this EMI protection for years and didn't know it.

I then tried other AR coated stock lenses and guess again?????

Yesssssss

Go Figure!


BTW, just a thought, how often do you place your spectacles one inch from an electrical outlet?

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## coda

The point isn't really to protect your eyes from the electromagnetic field around an electrical outlet but the field coming off a CRT display, particularly a computer screen which we all tend to sit rather close to.  In theory these coatings will reduce eye fatigue while using a computer, however summing the data I've seen there appears to be little _quantitative statistically significant_ proof of this but a fair amount of anecdotal evidence indicates value.  

It is worth noting that most of the lenses marketed as 'anti-static' have significant EMI shielding ability and even some AR coated lenses not specifically marketed as 'anti-static' will also provide EM shielding.

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## Chris Ryser

> *It is worth noting that most of the lenses marketed as 'anti-static' have significant EMI shielding ability and even some AR coated lenses not specifically marketed as 'anti-static' will also provide EM shielding.*


I would like to add that AR coatings by themselves are not anit static..........but the added hydrophobic layer might be having this feature.

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## DocInChina

> HELP !! My Oriental lens supplier keeps talking about EMI coating, what is it?? Looks to me just like a good AR. Is there a difference??


This EMI coating has been around for at least 8 years and is very popular in Japan and S. Korea. Lenses from those 2 countries are pretty much made with that coating now standard. 

Um...did you mean Asian lens supplier?  :bbg: I am an American but my company is Chinese and I live in China...am I also an Asian lens supplier? Confusing.

Doc

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## coda

> I would like to add that AR coatings by themselves are not anit static..........but the added hydrophobic layer might be having this feature.


Chris and I do love to disagree!  There are a number of inherently anti-static AR coatings in the marketplace, i.e. even without the addition of a hydrophobic layer they exhibit sufficient conductivity to be considered anti-static.  The earliest marketing of such I'm aware of was SOLA's UTMC AR coating (which had no hydrophobic coating at one point and may still not have one) but there may well have been more.  From a physics/materials standpoint it seems somewhat counter intuitive that a ceramic coating (because that's what AR coatings generally are) would be conductive but there are a number of physical phenomenon which can lead to significant conductivity.

To Chris' point, however, at least two top coat treatments claim to add anti-static properties, and I know at least one of them does (I haven't tested the other).  It's yet another instance of the potential value added benefits of top coats.

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## Steve Machol

> The earliest marketing of such I'm aware of was SOLA's UTMC AR coating (which had no hydrophobic coating at one point and may still not have one) but there may well have been more.


Interestingly enough I am still wearing a pair of the UTMC lenses using my original coating design.  These lenses are about 5-6 years old now and there are still no noticeable scratches or detioratioln.  And they are still anti-static. 

I'm pretty proud of that fact. :)

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## For-Life

> Interestingly enough I am still wearing a pair of the UTMC lenses using my original coating design. These lenses are about 5-6 years old now and there are still no noticeable scratches or detioratioln. And they are still anti-static. 
> 
> I'm pretty proud of that fact. :)


You know I rarely get a lens comeback that is coated with a premium AR that is scratched.  It is amazing.  I toss my glasses around like a rag doll and still no scratches.

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## Peter Z

The real key is to have a high quality thermal cure hardcoat applied to both surfaces and then a good A/R coating design.   The results are very little return product.  Too bad it took us a long time to release this.

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## Chris Ryser

> *I toss my glasses around like a rag doll and still no scratches.*


For-Life............go to the Gym more often .........then you can toss them around a little harder and you just might get some scratches on them.:D

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## For-Life

> For-Life............go to the Gym more often .........then you can toss them around a little harder and you just might get some scratches on them.:D


that's a shoot.

Actually I do go to the gym often :(

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## zain quadri

> help !!  My oriental lens supplier keeps talking about emi coating, what is it?? Looks to me just like a good ar. Is there a difference??


emi means electro magnetic infrence it works reduce reflaction of computer tv headlights of cars.its hv u v 400.

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## NithinReddy

> We started getting this EMI coating here in Israel about 2 years ago.
> It was fanfared in with much honour by the importer.
> 
> The lens rep came with some sample lenses and some sort of electronic meter scaled from 0 to 100   He placed the head of the meter one inch from an electrical plug outlet and the meter shot up to 100.   He then took an EMI coated lens and placed it between the plug and the meter and sure enough, this special EMI lens reduced the reading to a low number.
> 
> Very impressive I thought,  so I gave him my (then) 2 year old Panamic Trans 1.56 with Crizal and guess what?????  The meter reading went down to the same low number   WOW!  I've been having this EMI protection for years and didn't know it.
> 
> I then tried other AR coated stock lenses and guess again?????
> 
> ...


Can you tell what electronic meter device he used to measure  ??

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