First: do I allways need UV/IR filter glass and whats its purpose? What will happend without this "glass", NOT many "home made projestors" are made with this UV/IR filter, just few..


some OSRAM light "bulbs" has UV filter included and UV filtration is not REQUIRED:

HQI-TS, quartz technology


http://catalog.myosram.com/

type in search : HQI-TS 400W/NDL FC2 FLH1 (4500K ) and HQI-TS 400W/D FC2 FLH1 (5200K)




those has UV filter included... maybe there is no need for UV filtering?


and on fhe other side philips has 4500K and Osram 5200K what is BETTER? 4500 or 5200K !!!

philips are cheaper but HAS NO UV iltering in itself !!!


why is UV filtering so important

The glass is used to protect the LCD and fresnel from overheating. The UV filter may not be needed if the bulb used has a built in UV filter. If no UV filtering is used on the bulb and no other UV filter is added, the LCD will get burnt and will not last.
Most use Lexan plexiglass which would replace the glass and UV filter. It does both and can be bought at Home Depot.
From what I read it seems the closer to 6500K the better. The Ushio's we've been getting from Lumenlab are 4000K (or 4200K??) which is a little on the low side. Most would probably not notice the difference in color temperature though which would be a little more yellow than white. If you go higher than 6500K then you get into the blue spectrum which is not good either. Most Aquarium bulms use 10000-15000K which makes the water look more blue.

actually, I think the CRI index is probably more important.... it indicates how close the spectrum is relative to the sun.... the standard MH bulbs are around 65(on a scale of 100), anything over 90 is best ... there is also the question of where the peak frequencies are in the bulbs spectrum, but thats a little fuzzier and I'm not sure if that is taken into account in CRI/Kelvin calculations

HOW can UV destroy LCD?

UV is damaging to almost everything. It burns your skin, it deteriorates plastics and rubbers and much more.
An LCD is made up of thousands of little diodes which are made of silicon. Silicon ca be eaten away by the UV radiation if there is no UV filter on either the bulb or as a UV film/Lexan

To start, I just want to say that for safety reasons it is always safest to provide UV protection from a MH lamp. There are two types of MH lamps, ones rated for enclosed use, and ones rated for open use... typically the ones rated for open use have UV and explosion proof outer jacket. I would not consider a 'UV reduced' lamp entirely safe... especially since it is not open use rated... if you need a more difinitive answer you should contact the manufacturer and ask.

It has been debated whether the UV film is necessary to protect the LCD color filters. Without UV protection the fresnels will be exposed to whatever UV radiation is produced by the lamp. Clouding, discoloration and becoming brittle are known side effects of acrylic being exposed to UV... the problem is no one seems to be able to say with certainty how long of an exposure will render the fresnel "destroyed"... likely it all depends on the levels and spectrum that a person's particular lamp produces... I don't think any dangerous levels of UV are transmitted through to the screen, with or without a UV filter, as the light has to pass through so many frensels, glass, polarizers, color filters and lenses that there is no harmful UV left by the time it exits the triplet... however, any sort of light leaks from the light engine area can be considered harmful (to a person) so care should be taken to make this area "light leak proof"...

Here are some examples of spectrum transmissions on samples from an original polarizer that came off a CMV-520D, and also the basic linear polarizer from polarization.com... HERE

You can look through earlier posts for scans of Lexan XL10 and fresnels to see their transmission properties...

I found information HERE (look at page 5) concerning information on the different levels of UV... UVA, UVB and UVC... When we think of dangerous UV radiation, most of us think of UVB as this is what causes sunburn and skin cancer... we aren't generally exposed to UVA, but it is the most dangerous kind of UV.... need to check lamps to see what exactly is being produced for UV radiation...


I've tried to leave out my personal opinions on the matter and just deliver the facts... it would be up to you to decide if the lamp is safe for use without a UV filter, but I generally take the safest road, so I would say use the UV filter, then you know you are safe.

cheers,
gs

you think that "UV reduced" metal halidate lamp is not completely reduced od UV and UV filter shoul be applyed?

BUT I think of using CONDENSER(dont know its right name) lens in front of light "bulb" and this optic lens is made of GLASS, and EVERY glass except quarz glass FILTRATES UV?
Do I need than UV filter or not?

I think its up to you and how much you worry about UV, but my personal opinion would be that having any glass, even a condenser , between you(or the LCD) and the bulb is plenty of protection....

you think if I use condenser LENS in front of bulb I do not need UV filter?
But what most people who did make projector did about this UV filtering: did they use FILTER or not if they were using condenser len

I dont want my LCD be "destroyed" with UV ...

did anyone here their LCD get burned with UV?

thanks

yes.
yes.
yes. this is the safest method.

you've been given information on UV transmission, etc. it is entirely up to you to make your decision. use a UV filter and be safe.

cheers,
gs

I already ordered optics from Austria : www.diy-beamer.at they do not have UV filters... and I dont know where can I get it here where I live

Postal(posting) from USA is very expensive.. and posting will cost more than this filter cost..

What about "photographic" UV filters that are used for mounting on photo objectives etc...

short answer is try the photo filter and see..... the most anyone uses here is Lexan which should available in some form wherever you live... thats why they call it DIY ....
and if they(diybeamer) don't have uv filter, that might indicate they aren't too concerned about it .... I've never used a UV filter and I haven't had any problems.... but thats just me...

did you used UV filtered light bulb.. some light "bulbs" has UV filter included
did you use condenser lens?

no idea if my bulb is uv filtered(other than the glass surrounding the bulb), it is a T15 style bulb.... and yes, I use a pre-condenser between the bulb and the rear fresnel....

Do have the "bill" can you post the full name and model of this bulb? if no too much trouble

I know this is an old post but just so everyone knows, HID lamps produce UVB radiation.