I have 2 professional Theater lights that might be great for lcd projection, I'm not sure. I'm just starting to become interested in diy projectors, and wondering if these lights will be of use for a project. Here's the specs:
I have 1 ETC Source Four 50°, 575w HPL lamp that puts out 350 footcandles at 10ft, in a 9.3 foot circle. The great thing about this lamp is the wonderful mirror and small point source of the HPL lamp give it a very flat focused beam. Meaning it doesn't fade out towards the edge. It is very bright right out to the edge. Plus it is very easy to focus and crop out any extra space around an LCD panel.
It would probably use a small 5-6" lcd. The only problem I can see is that I would need to put the lcd inside the housing of the light to maintain focus. And this light gets very hot. It doesn't need a fan for the lamp, as it is built for the heat, but the lcd will probably melt if I don't add something else.
The other lamp I have is a 6" Altman Fresnel, 500w BTL lamp. It's light output varies with the focus from 925 footcandles at 2.8' width @ 10' to 88 footcandles at 14' width @ 10'. It doesn't have a flat focus at all, but it is much cooler, and the lcd might be able to be placed further from the lamp.
What do you guys think? Any use for these?
I have 1 ETC Source Four 50°, 575w HPL lamp that puts out 350 footcandles at 10ft, in a 9.3 foot circle. The great thing about this lamp is the wonderful mirror and small point source of the HPL lamp give it a very flat focused beam. Meaning it doesn't fade out towards the edge. It is very bright right out to the edge. Plus it is very easy to focus and crop out any extra space around an LCD panel.
It would probably use a small 5-6" lcd. The only problem I can see is that I would need to put the lcd inside the housing of the light to maintain focus. And this light gets very hot. It doesn't need a fan for the lamp, as it is built for the heat, but the lcd will probably melt if I don't add something else.
The other lamp I have is a 6" Altman Fresnel, 500w BTL lamp. It's light output varies with the focus from 925 footcandles at 2.8' width @ 10' to 88 footcandles at 14' width @ 10'. It doesn't have a flat focus at all, but it is much cooler, and the lcd might be able to be placed further from the lamp.
What do you guys think? Any use for these?
Here's some links to the lamps I have
ETC Source Four
http://www.etcconnect.com/docs_downloads/datashts/S4_50_Deg.pdf
The 575w lamp I have is between 8-12k lumens at 10 feet! Initial lumens at the lamp is 16,520. ! Good for projector guys?
Altman 6" Fresnel
http://www.altmanltg.com/fresnels/65.pdf
500w BTL at 11,000 lumens.
The color temp of these lamps are above 3k, which is not exactly white, but much whiter than normal halogen bulbs. But color temp can be compensated for with a filter such as Lee 202 Tungsten to Daylight Half CT Blue http://www.leefilters.com/LPFD.asp?PageID=194 or something similar that matches the correct temp.
Also Lee makes a filter called 269 Heat Shield http://www.leefilters.com/LP1.asp?PageID=49 that might be used to reduce the heat upon the LCD panel.
All these things can combine to create a very great projection result. Possibly a Polarizing filter to increase contrast? This is my first thoughts of this, so please give some feedback. I need to know if this is feasable, and anything I might have missed. Thanks!
ETC Source Four
http://www.etcconnect.com/docs_downloads/datashts/S4_50_Deg.pdf
The 575w lamp I have is between 8-12k lumens at 10 feet! Initial lumens at the lamp is 16,520. ! Good for projector guys?
Altman 6" Fresnel
http://www.altmanltg.com/fresnels/65.pdf
500w BTL at 11,000 lumens.
The color temp of these lamps are above 3k, which is not exactly white, but much whiter than normal halogen bulbs. But color temp can be compensated for with a filter such as Lee 202 Tungsten to Daylight Half CT Blue http://www.leefilters.com/LPFD.asp?PageID=194 or something similar that matches the correct temp.
Also Lee makes a filter called 269 Heat Shield http://www.leefilters.com/LP1.asp?PageID=49 that might be used to reduce the heat upon the LCD panel.
All these things can combine to create a very great projection result. Possibly a Polarizing filter to increase contrast? This is my first thoughts of this, so please give some feedback. I need to know if this is feasable, and anything I might have missed. Thanks!
Cant do it.....those lights are halogen and put out way, way, way too much heat. Now if you retrofit it for a metal halide you might have a chance......The LCD will fry if you try using that stagelight the way it is......i was thinking of the same thing a few months ago. The "heat shield" wont really be enough for it anyway.....you know how hot the bodies of those get as well.....they can do some serious damage....
but there's so much potential there. There's got to be a solution for the heat. The whole great thing about this light is the lamp and reflector design. The lamp is about as close to a point source as you can get, making the beam focus extremely flat.
Be my guest to start working on a solutions. I have a few suggestions....Ditch the Halogen bulb inside it. I would suggest replacing the bulb with a tubular Metal halide bulb of 400W....in fact the ceramic constant color series would be great from GE.....Next you still need to incorporate some form of fan within the fan enclosure otherwise you will still have a bit of the heat problem......I would owrk with the ellipsoidal, but you have an issue with the lenses it currently uses.....those lenses are designed for a very long throw for the light and most of us are dealing with rooms that are 15 feet or less in length wich will necessitate a change in lenses...unless you want a picture that is only a couple feet long.
I disagree with ditching the halogens and fitting replacement sources. I think that would end up being a complete engineering nightmare. I thought of using stage lights quite a while ago, but didn't have access to any and didn't want to spend much money to get one. The reflector and lens designs in the stage lights have had lots of effort go into them, so I think it is good to use the stage light as is, with pretty good IR filtering and collimating lens on the output to produce the correct convergence through the LCD. You would have to fan cool the IR filter material, perhaps consider the low-E glass or the IR blocking film that was discussed some time ago. The film was developed specifically for stage lights, I don't have the web link, but do some forum searching and you should find it. Perhaps two sheets of glass with the film attached, and forced air cooling between the sheets.
Good luck, honestly......i've worked around stage lights on a regular basis, and even with IR blocking material they still get extremely hot..Plus the sides of the light also get prety hot too.
Doesn't really matter that the light and light housing itself gets really hot. What matters is the radiated IR content of the light output. Of course you don't want the stage light heating the display or anything else through conduction because it is all bolted together or anything. Perhaps additional heat sinks attached to the light housing and forced air cooling over those.
But as far as the radiated heat, put a thermometer on a target surface before putting the LCD there to check the effectiveness of IR blocking filter material or use the hand test. If you can keep your hand there indefinitely, then it is OK for the lcd.
But as far as the radiated heat, put a thermometer on a target surface before putting the LCD there to check the effectiveness of IR blocking filter material or use the hand test. If you can keep your hand there indefinitely, then it is OK for the lcd.
I don't think you guys understand this lamp very well. It is one of the newest designs in stage lights, and has set a new standard in the theatre world. It doesn't have alot of the issues older stage lights have. For one thing, the housing does not get very hot. Most of the body is insulated from the heat. Also, the lamp is only 575w vs. 1k of usual stage lights. The lamp and reflector are designed to perfectly match to create a flat beam rather than being brighter at the center and fading off like most lights do. Changing the lamp would certainly undermine this design and remove one of the key benefits of using this type of lamp for a projector. Lastly, this light is a short throw light. It is 50°. Meaning at 15', it will have a beam diameter of about 14'. I think that is plenty big enough for anyones home movie screen! The multiplying factor is 0.93, so use this to figure the diameter at any distance. Multiply the distance by 0.93, and this is the beam diameter.
I can order IR filter sheets from Leefilters, they also might have a glass version. Where can I get that Low-e glass mentioned?
The main issue right now is finding a way to get airflow to the correct spot. There's no easy access to that part of the lamp to fit a fan. I think a combination of the filters with good airflow will give an operable temperature. The hand test will fail I'm sure, so I won't bother burning myself for no reason. The thermometer is a great idea. Should probably have one there permanently anyway, so I can gauge the temp of the lcd over time.
I can order IR filter sheets from Leefilters, they also might have a glass version. Where can I get that Low-e glass mentioned?
The main issue right now is finding a way to get airflow to the correct spot. There's no easy access to that part of the lamp to fit a fan. I think a combination of the filters with good airflow will give an operable temperature. The hand test will fail I'm sure, so I won't bother burning myself for no reason. The thermometer is a great idea. Should probably have one there permanently anyway, so I can gauge the temp of the lcd over time.
you're right I don't know these lights! But I can comment on the general application of them I think.
The fact that the body doesn't get hot is a bonus, sounds like a fantastic unit.
However, I would point out that the beam spread of the unit is almost immaterial, as it is the projection lens that determines the throw distance and screen size of the projection system. You really want a parallel or even converging beam through your lcd, so you will HAVE to add lens of some sort between light <> LCD.
The uniformity of light over the beam is an important factor, and this sounds like it is really good.
Concentrate on the IR filtering, if it fails the hand test don't put an lcd there, you will only damage it unless it is a special high temp poly si one or something.
The way I read your post is that you are thinking of directing a fan at the bulb somehow. If the housing of the light is not overheating, don't bother. It won't do anything to the IR emmitted from the light itself. Single or multiple IR filter sheets in front of the unit with air cooling over or between them is the answer.
The fact that the body doesn't get hot is a bonus, sounds like a fantastic unit.
However, I would point out that the beam spread of the unit is almost immaterial, as it is the projection lens that determines the throw distance and screen size of the projection system. You really want a parallel or even converging beam through your lcd, so you will HAVE to add lens of some sort between light <> LCD.
The uniformity of light over the beam is an important factor, and this sounds like it is really good.
Concentrate on the IR filtering, if it fails the hand test don't put an lcd there, you will only damage it unless it is a special high temp poly si one or something.
The way I read your post is that you are thinking of directing a fan at the bulb somehow. If the housing of the light is not overheating, don't bother. It won't do anything to the IR emmitted from the light itself. Single or multiple IR filter sheets in front of the unit with air cooling over or between them is the answer.
Hi Folks
I am very familiar with the S4, I use them virtually every day!
The reflector of the lamp is based on what ETC call a cold mirror, i.e, it uses a dichroic thin film reflector that is transparent to IR. This reduces the gate temperature to about 120C, still way too hot for LCD panels. ETC make a discharge lamp version for architectural uses, but this has a separate ballast and is quite expensive.
The Lee Heat filter is commonly used to increase the life of lighting gel, but I don't think it would work too well as the reduction is fairly minor, amd it is only good for about 100 hours before it fails, but hey, if you paired up several sheets with fan cooling between them and replaced them frequently it might work ok.
Optically, they use pretty good lenses for stage lighting units, but the quality is nowhere near sharp enough for video projection, and colour fringing can be a problem.
Sorry...
I am very familiar with the S4, I use them virtually every day!
The reflector of the lamp is based on what ETC call a cold mirror, i.e, it uses a dichroic thin film reflector that is transparent to IR. This reduces the gate temperature to about 120C, still way too hot for LCD panels. ETC make a discharge lamp version for architectural uses, but this has a separate ballast and is quite expensive.
The Lee Heat filter is commonly used to increase the life of lighting gel, but I don't think it would work too well as the reduction is fairly minor, amd it is only good for about 100 hours before it fails, but hey, if you paired up several sheets with fan cooling between them and replaced them frequently it might work ok.
Optically, they use pretty good lenses for stage lighting units, but the quality is nowhere near sharp enough for video projection, and colour fringing can be a problem.
Sorry...
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