One thing that I find strange is how some people can be so thorough finding the perfect projection lense to get more brightness but then when it comes to protecting the LCD the just go with lexan.
For my projector I found a filter that was made to filter out Infared and it does UV as well. It is called a cold mirror. Unlike lexan it actually reflects the IR and UV light so this means that it doesn’t heat up as much. What I have is 4”x4” pieces of this high quality glass. I first bought some a year ago because I wanted to try it for mine but Rosco wouldn’t let me buy just one, so I have some extra ones that you are welcome to buy from me if you want to experience more brightness from your projector.
I found a way to demonstrate how well my IR/UV cold mirrors work. I have my video camera set in night shot and here you can see how all the IR light from the camera is reflected by the glass.
For my projector I found a filter that was made to filter out Infared and it does UV as well. It is called a cold mirror. Unlike lexan it actually reflects the IR and UV light so this means that it doesn’t heat up as much. What I have is 4”x4” pieces of this high quality glass. I first bought some a year ago because I wanted to try it for mine but Rosco wouldn’t let me buy just one, so I have some extra ones that you are welcome to buy from me if you want to experience more brightness from your projector.
I found a way to demonstrate how well my IR/UV cold mirrors work. I have my video camera set in night shot and here you can see how all the IR light from the camera is reflected by the glass.
You are right about a cold mirror and it does work very well. There are a couple of down sides to it though. The first is obviously price. I whole heartedly admit that I don't know how much a piece can be purchased for today but a couple of years ago it was very pricey and you had to buy in bulk unless you were one of the lucky ones that could get a free sample from some manufacture. So anytime people talked about cold mirrors there was also talk of group buys and things like that. The second is availability. Lexan, for the most part, can be purchased at the local home center. A cold mirror would have to be ordered online for most DIYers. Lastly would be your design now has to incorporate the mirror which complicated things. Granted it's not that big of a deal to have a folded design instead of a straight thru design but some might not like to complicate things even more. Otherwise thanks very much for the reminder. I sure there are a few people that could and would benefit from the use of a cold mirror. Another nice tip would be to use a cold mirror reflector if you can find one. Then you only have to worry about the UV & IR coming directly from the bulb instead of the combination of direct and reflected light.
Zaner21
Zaner21
I have have 6 of them left still since I bought 10 and have sold a few. They are 4"x4" cold mirrors from Rosco. I can get you one shipped for $60 CAD or thats about $51 of your American bills.
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An externally hosted image should be here but it was not working when we last tested it.
I do also have 2 extra 5 1/2" Dia mirror (I don't believe they have a coating on them) but they are ground and very very high quality. They are perfectly matched to my optics as they have a 320mm Fl. If anyone is interested in one of these I will happily part with them.
Here are some pics of my reflectors as well. The last picture the camera is just about an inch away; you can see the amazing quality of this mirrors. They will allow you to get very good arc images if they match your optics.
You can not understand the quality of these "reflectors" until you see them. Objects look better quality in the reflection you see with these mirrors then if you looked directly at the object.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
You can not understand the quality of these "reflectors" until you see them. Objects look better quality in the reflection you see with these mirrors then if you looked directly at the object.
Oops, I didn't relize till now but you are mistaken about how the "cold mirror" operates. What it is reflected is the Ir and UV not the visible light. So you simple place the filter directly in line with your light.
On my projector it is in a light box and is about 1 1/2" away from the bulb.
The pictures I have added above should help you see this but the cold mirrors appear to just be a normal piece of transparent glass.
On my projector it is in a light box and is about 1 1/2" away from the bulb.
The pictures I have added above should help you see this but the cold mirrors appear to just be a normal piece of transparent glass.
Hey
I am using the 15.4" widescreen Sharp WUXGA. I just removed the Antiglare off of it a couple days ago.
I am using the 15.4" widescreen Sharp WUXGA. I just removed the Antiglare off of it a couple days ago.
Whatmough said:
lol. Well I guess we are each talking about a different type of cold mirror. When I read "cold mirrror" I think of a dielectric mirror like the ones that are used in commercial projectors for their reflectors. It looks like a mirror but if you look close you can kind of see thru it little bit and everything is bluish purple color. It reflects the visible light while transmitting the IR. I guess the "cold mirror" your have is just opposite, passes the visible light and reflects/absorbs the IR and UV.
Zaner21
http://en.wikipedia.org/wiki/Cold_mirror
A cold mirror is a specialized dielectric mirror, a dichromatic interference filter that operates over a very wide temperature range to reflect the entire visible light spectrum while very efficiently transmitting infrared wavelengths. Similar to hot mirrors, cold mirrors can be designed for an incidence angle ranging between zero and 45 degrees, and are constructed with multi-layer dielectric coatings, in a manner similar to interference filters. Cold mirrors can be employed as dichromatic beamsplitters with laser systems to reflect visible light wavelengths while transmitting infrared.
http://en.wikipedia.org/wiki/Interference_filter
An interference filter or dichroic filter is an optical filter that reflects one or more spectral bands or lines and transmits others, while maintaining a nearly zero coefficient of absorption for all wavelengths of interest. An interference filter may be high-pass, low-pass, bandpass, or band-rejection.
An interference filter consists of multiple thin layers of dielectric material having different refractive indices. There also may be metallic layers. In its broadest meaning, interference filters comprise also etalons that could be implemented as tunable interference filters. Interference filters are wavelength-selective by virtue of the interference effects that take place between the incident and reflected waves at the thin-film boundaries.
Bandpass filters are normally designed for normal incidence. However, when the angle of incidence of the incoming light is increased from zero, the central wavelength of the filter decreases, resulting in partial tunabilty....
Hey,
My projector is back up after removing the antiglare. Everything needs to be realigned buy it is much brighter than before. You cannot tell from this picture but each pixel is perfectly focused and it is very clear.
My projector is back up after removing the antiglare. Everything needs to be realigned buy it is much brighter than before. You cannot tell from this picture but each pixel is perfectly focused and it is very clear.
An externally hosted image should be here but it was not working when we last tested it.
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