Lexan does NOT filter out UV

[ace3000_1]

UV filters are inherent in the following products, polycarbonate, mid and hi-index lens materials, photochromic glass and plastic. Regular CR-39 plastic needs a special inexpensive filter to be added to protect you from UV light and this process can be done at Eyewear Concepts’ On-site optical lab.

Eyewear lenses are not Lexan XL.

At the end of the day its upto you guys. Lexan is not a classed UV filter, if it was it would be sold so, and with a 20% visible light loss, no thanks for me, and i state me.

I guess it comes down to how picky you want to be and how long you want a system to last, this all comes with a $ sign. No matter how much you pay for a UV filter they will never remove 100% UV, thats why your cheap frensels will still go yellow over time. A UV filter only buys you time. The cheaper the filter the less time you have.

The more exspensive "classed" UV filters are designed for what we need in projection and therfore have the higher transmisive rating. A 20% visible light loss is alot.

Trev🙂

 

[TaskMaster]

Eyewear lenses are not Lexan XL.

The statements apply to all grades of polycarbonate - Lexan XL or not. Make lenses, windows, or doors out of it... whatever you like.😀

Polycarbonate is a UV filter, if it wasn't polycarbonate lenses would need UV coatings just like other lenses to protect the wearer's eyes. Some may not be happy with the visible light transmission, but nobody should be mislead into thinking polycarbonate does not filter UV. The simple and plain fact is that it does to answer the original question posed in this thread.

 

[ace3000_1]

All of our $39.00 complete pair packages are made using polycarbonate lenses; the lightest, most impact-resistant material made. With an index of refraction of 1.59, they are much thinner than standard (CR39) optical lenses. They also come with both 100% UV and tough scratch-resistant coatings applied to both sides of the lenses, as well as polished lens edges, at no extra charge.


If Polycarbonate filterd UV in a resonable standard, then tell me why they state here they coat their polycarbonate lenses with a UV coating.

http://www.39dollarglasses.com/info_pop/lenses.html

Lexan comes in manny grades, dont be fooled by the specs, some will block more UV then the other, this goes for any optical medium, and at different temperatures. Lexan Solar blocks IR, Lexan XL wont, standard polycarbonate is not UV treated (to cut medium fading) ect.

Polycarbonate is a UV filter,

Why isnt it sold so then? Why isnt glass sold as a UV filter in its standard form? afteral glass blocks UV aswell and lexan XL only blocks 10% more of it in a standard form.

Lexan is not a UV filter, it has the ability like glass to block SOME UV nativley only. With its poor transmisince of visible light on the Lexan XL grade it would never make it in the optical world of filters, its also not designed to be a filter. Thats why its not sold as one, and why other coatings are added to it.

Trev🙂

 

[dj_holmes]

ACE bruv we know your smat but your CLEARLY looking to argue this to death!!! 😉

but think about it. if it blocks SOME of the uv then it IS a uv filter. come on bruv i don't want to fuel you anger here but if u got SOME money in your pocket then you HAVE money no matter how much it is!😉

but forget all that nonsense anyway. ll the nowledge you guys have shared has been like wow.

but i really need to know where in the hell can i get some in the u.k. london to be more specific.. please please if anyone knows of a departmnt store or something like that, that i can visit. i tried looking on internet but noooo.

thanx a bunch guyssssssss

 

[ace3000_1]

Wow! Trev is back!

Heya Ancorp, good to see yaself around mate 🙂, been a while.

Ive taken abit of a break as of late and doing a heavy comp modd while im waiting on a reflector from 18wheeler, so i havnt been around too much.

Have a good one mate.
Trev 🙂

 

[ace3000_1]

ACE bruv we know your smat but your CLEARLY looking to argue this to death!!!

Im not arguing here im just stating facts, technically its not a UV filter unless its classed as one and if it falls within certain limits of a certain specification.. The same goes for glass.

The best thing to do is to buy a bulb with an inbuilt UV filter, no light loss, and its a filter that can not only take the heat, but also the intensity.

Trev 🙂

 

[dj_holmes]

bruv i got a hqi 150w i don't think it has uv filter built in ANY suggestion on what can be done? tricks tips?? trade secrets

 

[ace3000_1]

You got the exact model number of the bulb?

Trev🙂

 

[ace3000_1]

Taskmaster, run up a search on UV400, thats whats used in UV protected grade polycarbonate lenses.

Trev🙂

 

[dj_holmes]

i ordered it from germany its.........

hit-de 150nw rx7s
art. -nr. 221504

i also found a uv-p sign on it but thats almost every writing on the box.

on the bulb it had f-18921 on it.......but thata everthing

i was hoping to switch to 5100k daylight aswell soon!! 4200k at the mo'

 

[ace3000_1]

UV-P stands for UV protected 🙂, so its got a UV filter in it.

Trev🙂

 

[dj_holmes]

NO WAY🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂

so does that mean i don't need protection? but the funny thing is no body actually says how long usage damages colours. i mean say 150w hqi without filter on a 7" lilliput how long before damage roughly, 2 years 5 10 etc??😎

 

[ace3000_1]

Ya you dont need another filter, having another filter is more or less pointless.

Im not sure how long a lcd can last without a UV filter, but ive had a halogen fade a lcd and frensel before after about 300hrs of use without one.

Ive clocked up way over 2k hrs in testing, and my lcd looks the same as the brand new spare i have using bulbs with a uv filter.

Trev🙂

 

[dj_holmes]

well you sure are smart and smart people benefit in life...i just saw your 7" lilliput projector...wow...hello some serious business!!!!!

u just helped me in more ways than you know

take it easy mate 😉 🙂 😎

 

[ace3000_1]

Thanks for the nice words DJ 😉. That projector in the other thread is old now, ill have the new up soon, there has been manny changes. Ill post up the projector when its done.

Have a good one buddy.
Trev🙂

 

[TaskMaster]

If you say polycarbonate doesn't block UV and that is a fact, I would have to agree... an incorrect fact.

Polycarbonates are, as the previous quote stated (about Lexan), "essentially opaque at all wavelengths below 385 nanometers." Coatings and additives are to protect the polycarbonate, but with or without them, polycarbonate does not transmit UV. Without protection the polycarb will degrade over time, but still it will not transmit the UV spectrum. If you find this hard to believe take a piece to an optician and see for yourself.

DJ_Homes - Just to be clear, it doesn't just block some UV, it blocks virtually all. If you look at the graph MegaMan linked to it shows the same data. I am just stating fact you can verify in any Engineering Thermoplastics Handbook.

Whatever you want to call it, polycarbonate by any name still blocks UV.

 

[ace3000_1]

If you say polycarbonate doesn't block UV and that is a fact, I would have to agree... an incorrect fact

If read back in my posts, i never said it didnt block uv, i told you its not a UV filter.

Whatever you want to call it, polycarbonate by any name still blocks UV.

.....at different levels at different grades, just like glass or any other optical medium.

Trev🙂

 

[TaskMaster]

All of our $39.00 complete pair packages are made using polycarbonate lenses; the lightest, most impact-resistant material made. With an index of refraction of 1.59, they are much thinner than standard (CR39) optical lenses. They also come with both 100% UV and tough scratch-resistant coatings applied to both sides of the lenses, as well as polished lens edges, at no extra charge.


If Polycarbonate filterd UV in a resonable standard, then tell me why they state here they coat their polycarbonate lenses with a UV coating.

http://www.39dollarglasses.com/info_pop/lenses.html

Trev🙂

Since you asked: lenses are coated because unprotected polycarbonate is degraded by UV, but regardless, it still does not transmit it. The coating is to protect the lens only. That is why it is applied to both sides - otherwise why would you coat the inside? So peripheral UV coming at the lens can be better reflected into your eye?

 

[TaskMaster]

.....at different levels at different grades, just like glass or any other optical medium.
Trev🙂

Nope, all grades of polycarb have the same polymer chain which is responsible for the UV blocking charateristics. Call it a blocker, call it a filter (I am using the terms interchangeably), UV doesn't pass through the plastic to the other side.

 

[ace3000_1]

Since you asked: lenses are coated because unprotected polycarbonate is degraded by UV,

UV stabilised polycarbonate isnt. How do you know they use a Polycarbonate thats not UV stablised?

That is why it is applied to both sides - otherwise why would you coat the inside?

The coating is there so the UV filtering can be at a higher level then what Polycarbonate realy is in its native state, its to save your EYES!!!

The coating on the back is to filter the reflected light going back to your eye from angles on the sides.

As stated before search UV400. If polycarbonate was so great in its native state, then why is there UV400 in optical glasses?

Trev🙂