W
willie
I have a Sharp QA-1500 that I'm going to strip down and make a "real" projector out of. My question is this:
Do projection panels need UV filters?
Like all other projection panles, the lcd on the QA-1500 is sandwiched between two pieces of glass. Does anybody know if this is UV glass. I have the manual but it doesn't say, and people have been putting these things directly on OHP's without adding one (a UV filter). Having said all that, if it does need one, does anybody know a good source? Thanks.
Do projection panels need UV filters?
Like all other projection panles, the lcd on the QA-1500 is sandwiched between two pieces of glass. Does anybody know if this is UV glass. I have the manual but it doesn't say, and people have been putting these things directly on OHP's without adding one (a UV filter). Having said all that, if it does need one, does anybody know a good source? Thanks.
Uv
Good question, the answer in an ideal world is yes as all OHP's do pump out some UV, however most OHP's will hav UV filters on the optics....have a look, they look like a greenish coating on the lens, it will cut down the amount of UV an awful lot. THe problem is that UV filters are quite expensive for good one's, and I have no idea where you could get one large enough for an OHP tray, howver I guess you could use a pice of "LOW-E" insulated glass, as this glass cuts out UV and IR. If you are using an MH lamp in a true DIY setup, then a uv filter is an absolute must!, those lamps pump out an awful lot of UV. The best option is possible a cold mirror which will reflect visible light but will transmitt UV and IR. This could mean you could also have a smaller projector by bending the light path, small mirrors are not expensive, have a search on the net. Basically there is no harm in adding a UV filter, though you will get away with a pannel on an OHP for ages and ages before any dammage is done.
Another problem with UV is often overlooked, that is if you are watching a projector on a high gain screen in a dark room, many high gain screens will reflect an awful lot of UV straight into your eye......so it's not good again in the long run.
As for the Sharp QA-1500, I would guess it does not have a UV filter on the pieces of glass, they are there to keep dust and people's dirty mitts off the actuall screen, and to allow efficient air circulation with a smaller fan. The panels would assume you have a UV filter in the optics of the OHP.
Hope this helps.
Good question, the answer in an ideal world is yes as all OHP's do pump out some UV, however most OHP's will hav UV filters on the optics....have a look, they look like a greenish coating on the lens, it will cut down the amount of UV an awful lot. THe problem is that UV filters are quite expensive for good one's, and I have no idea where you could get one large enough for an OHP tray, howver I guess you could use a pice of "LOW-E" insulated glass, as this glass cuts out UV and IR. If you are using an MH lamp in a true DIY setup, then a uv filter is an absolute must!, those lamps pump out an awful lot of UV. The best option is possible a cold mirror which will reflect visible light but will transmitt UV and IR. This could mean you could also have a smaller projector by bending the light path, small mirrors are not expensive, have a search on the net. Basically there is no harm in adding a UV filter, though you will get away with a pannel on an OHP for ages and ages before any dammage is done.
Another problem with UV is often overlooked, that is if you are watching a projector on a high gain screen in a dark room, many high gain screens will reflect an awful lot of UV straight into your eye......so it's not good again in the long run.
As for the Sharp QA-1500, I would guess it does not have a UV filter on the pieces of glass, they are there to keep dust and people's dirty mitts off the actuall screen, and to allow efficient air circulation with a smaller fan. The panels would assume you have a UV filter in the optics of the OHP.
Hope this helps.
You can get Lexan at a place like Home Depot. One side is coated to block UV. You face the coated side toward the light. It comes in all sorts of sizes. There are instructions right on it.
W
willie
Thanks to both of you for the replies. Lots of good info! I don't need a real big piece, because I'm going to pull the lcd from the panel. It's only 8.4 inches. I'll definately check that out a home depot.
Hello. I am a newbie reading a lot lately. Wondering if camera UV lens filter can be used as it is readily available.
UV
Assuming it can take the potentially high temperatures it would be ok to use, however it may not be as good as you might imagine, camera UV filters are not as good/efficient as people might think, in fact they are designed to only block frequencies that film is sensitive to, but it would be better than nothing! Many UV filters for cameras, appear to be made of glass, but are in fact made of plastic (I know this sounds silly, but some plastic these days really does look and feel like glass!), so be aware of this, your filter could melt. I guess it’s a case of trial and error. Sorry I can’t be of any more help/more specific.
Hope this helps.
Assuming it can take the potentially high temperatures it would be ok to use, however it may not be as good as you might imagine, camera UV filters are not as good/efficient as people might think, in fact they are designed to only block frequencies that film is sensitive to, but it would be better than nothing! Many UV filters for cameras, appear to be made of glass, but are in fact made of plastic (I know this sounds silly, but some plastic these days really does look and feel like glass!), so be aware of this, your filter could melt. I guess it’s a case of trial and error. Sorry I can’t be of any more help/more specific.
Hope this helps.
where at home depot? i went to one here in Canada and when i asked 2 different guys that work there all i got were blank faces...they dont know what it is...
Lexan
mindless_fool, I believe i'm right in saying that Lexan is just a brand name of glass. What you need to ask for is insulated glass. Basically it's glass that has argon (I believe) gas sealed inbetween two shets of glass. It's often called 'Low-E glass'.
here is a link you might find useful, it gives you a bit of a description of it:
http://www.wilbermanufacturing.com/loweglass.htm
Here in the UK you can get it premade in various sizes, the smaller one's e.g. 10" square are quite reasonable in price.
Here is a site where the builder has used low-e glass in his projector - it's a very impressive build, well worth a look, near the bottom it talks about low-e glass.
http://www.hommie.net/construction.htm
Hope this helps
mindless_fool, I believe i'm right in saying that Lexan is just a brand name of glass. What you need to ask for is insulated glass. Basically it's glass that has argon (I believe) gas sealed inbetween two shets of glass. It's often called 'Low-E glass'.
here is a link you might find useful, it gives you a bit of a description of it:
http://www.wilbermanufacturing.com/loweglass.htm
Here in the UK you can get it premade in various sizes, the smaller one's e.g. 10" square are quite reasonable in price.
Here is a site where the builder has used low-e glass in his projector - it's a very impressive build, well worth a look, near the bottom it talks about low-e glass.
http://www.hommie.net/construction.htm
Hope this helps
so will low-e glass also block some of the heat put out by the lamp as well as UV?
i heard that lexan was a type of plexiglass coated with a UV filter...
i heard that lexan was a type of plexiglass coated with a UV filter...
Low-e
Yep, Low-E is a "pane of glass that selectively blocks out UV and IR light while maximizing the amount of visible light that passes through the glass unit"
Bascially they have a thin film on the inside that blocks IR and UV and the argon helps to insulate the two sides of the panel. It works very well. Plus it would be very expensive to get a UV and IR filter of equlivant size elsewhere, e.g. 12" by 12".
Check out:
http://www.drwastchak.com/index.php?Page=articles7
That page is well worth looking at if you are interested as it describes the various methods that low-e (or low emission) glass works, e.g. hard or soft coatings, and which makes are best ect........
Yep, that's just one of the products out of a long list that they make.........
Again, hope this info is useful to you all, as a matter of fact, I plan to use a pice of 12" by 12" Low-E glass just after my light souce to keep heat down...........
Yep, Low-E is a "pane of glass that selectively blocks out UV and IR light while maximizing the amount of visible light that passes through the glass unit"
Bascially they have a thin film on the inside that blocks IR and UV and the argon helps to insulate the two sides of the panel. It works very well. Plus it would be very expensive to get a UV and IR filter of equlivant size elsewhere, e.g. 12" by 12".
Check out:
http://www.drwastchak.com/index.php?Page=articles7
That page is well worth looking at if you are interested as it describes the various methods that low-e (or low emission) glass works, e.g. hard or soft coatings, and which makes are best ect........
Yep, that's just one of the products out of a long list that they make.........
Again, hope this info is useful to you all, as a matter of fact, I plan to use a pice of 12" by 12" Low-E glass just after my light souce to keep heat down...........
ya i wanted to get a ir filter too..so this is a 2 in 1 solution...cool i need a 12x10 inch piece..got to call home depot here and see if they can get me that
Size
Often you find if u order an odd/non standard size, they will quote u a price for a custom job without telling you/making you aware, it is always worth asking if the size you want to order is a 'standard' size, as it will be much cheaper obviousley than a custom order, however firms who make the panels can make you any size you want....
Often you find if u order an odd/non standard size, they will quote u a price for a custom job without telling you/making you aware, it is always worth asking if the size you want to order is a 'standard' size, as it will be much cheaper obviousley than a custom order, however firms who make the panels can make you any size you want....
I just went out and found some LOW- E glass for my Pj's. I checked around different places and the best price I could find it was about $5.15/sq. ft. I tried Home Depot but they didn't know what I was talking about.
I went to a local glass store. I didn't have any luck with home depot so I started calling glass shops in my area. Luckily I found one who had it in stock at a good price. Most shops that I talked with that dealt with glass are familiar with Low E but most of them didn't know about the IR part of it though.
well the glass is supposed to filter both but I had the misfortune of speaking with some real idiots. They handed me a tech sheet that had all the info on it. I'm going to see if I can get a friend to scan it for me and I'll post it here.
Guys id just like to point out that low-e glass is no where as affective as buying the correct filter, if you think about it, shoving concentrated light at 20000lm's compaired to normal sunlight is a big diff. Low-e glass will not filter out the uv required to prolong the life of the lcd as its simply not strong enough. If it has a film coating, that may also melt which brings me to the point of saying, window glass also explodes with high heat generated from such sources as a mh lamp.
Normal glass also will not filter out uv, well it does, but even at sunlight measuments, its basically nothing. If it did filter out a great deal of uv light then the outer glass on the bulbs would stop the uv, the outer glass on the bulbs dont stop uv, so they incorporate a uv filter with a quartz on the inner arc tube. That is ofcourse an optional incorporational measure you can get with certain bulbs like the hqi-tsd.
Im also going to mention that MH lamps projuce more uv light then any other lamp on the market, a proper uv filter is a must if you dont buy a bulb with an incorporated inbuilt uv block.
I read earlier that lexan can be another name for low-e glass, not true, lexan is a polycarbonate plastic acrylic, another name for it is plexi glass. Plexi and lexan can stop uv light in the right optical grade, but at 200euro for a 1x2m sheet, it doesnt come too cheaply, and i might add you do have heat issues if you place it in a poorly designated place within your projector. Cooling on plexi and lexan is a must if it is going to be placed within 4inches of your light source.
The only way to filter uv light in an efective manner is to use a proper uv filter thats temperd, or to get a bulb with a uv filter built in, as they say, you get what you pay for, the risks are totally in your hands.
Trev🙂
Normal glass also will not filter out uv, well it does, but even at sunlight measuments, its basically nothing. If it did filter out a great deal of uv light then the outer glass on the bulbs would stop the uv, the outer glass on the bulbs dont stop uv, so they incorporate a uv filter with a quartz on the inner arc tube. That is ofcourse an optional incorporational measure you can get with certain bulbs like the hqi-tsd.
Im also going to mention that MH lamps projuce more uv light then any other lamp on the market, a proper uv filter is a must if you dont buy a bulb with an incorporated inbuilt uv block.
I read earlier that lexan can be another name for low-e glass, not true, lexan is a polycarbonate plastic acrylic, another name for it is plexi glass. Plexi and lexan can stop uv light in the right optical grade, but at 200euro for a 1x2m sheet, it doesnt come too cheaply, and i might add you do have heat issues if you place it in a poorly designated place within your projector. Cooling on plexi and lexan is a must if it is going to be placed within 4inches of your light source.
The only way to filter uv light in an efective manner is to use a proper uv filter thats temperd, or to get a bulb with a uv filter built in, as they say, you get what you pay for, the risks are totally in your hands.
Trev🙂
W
willie
What about something like this?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15219&item=3823919096&rd=1
It seems like it would do the job. It's a little small though.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15219&item=3823919096&rd=1
It seems like it would do the job. It's a little small though.
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