This PJ concept was inspired by the drawing ap0the0sis posted in This Post.
I have been seeing a lot of broken and for parts only PJ being sold on ebay, and I got to thinking what might a broken multi-LCD system PJ might be good for. This is what my daydreaming came up with. Will it work?
Here are the main points of the design:
1. This is the Lighting Array. It is basicly just 3 of your DIY type 100-250 watt metal halide bulbs with reflectors. All of them are set to fire and focus their light into the center of the prism chamber.
2. This is the prism chamber.as the light travels out of the reflector apature it passes through an IR/UV filter and into the prism in the center, where it is reflected to the condenser fresnel that is focuses onto the LCD Stage Section
3. This is the LCD Stage. as the light passes through the stage it goes through a second fresnel to streighten out the light. That light then passes through a sheet of that 3M polar recycler film to get it all set to pass through the LCD. When the light gets to the LCD is is well conditioned to pass through the LCD panel, it is cool and the harmful UV is gone to protect your media, and it is all polar alligned to pass through the LCD without losing so much in the transmission. Once through the LCD there is a dead air space for cooling and finally a fresnel to get the LCD image hurded in the right direction and focused on the projection lens.
4. The projection lens. Ideally this would have zoom capability to control image size.
Well there it is guys, how crazy is that?
CB.
I have been seeing a lot of broken and for parts only PJ being sold on ebay, and I got to thinking what might a broken multi-LCD system PJ might be good for. This is what my daydreaming came up with. Will it work?
Here are the main points of the design:
1. This is the Lighting Array. It is basicly just 3 of your DIY type 100-250 watt metal halide bulbs with reflectors. All of them are set to fire and focus their light into the center of the prism chamber.
2. This is the prism chamber.as the light travels out of the reflector apature it passes through an IR/UV filter and into the prism in the center, where it is reflected to the condenser fresnel that is focuses onto the LCD Stage Section
3. This is the LCD Stage. as the light passes through the stage it goes through a second fresnel to streighten out the light. That light then passes through a sheet of that 3M polar recycler film to get it all set to pass through the LCD. When the light gets to the LCD is is well conditioned to pass through the LCD panel, it is cool and the harmful UV is gone to protect your media, and it is all polar alligned to pass through the LCD without losing so much in the transmission. Once through the LCD there is a dead air space for cooling and finally a fresnel to get the LCD image hurded in the right direction and focused on the projection lens.
4. The projection lens. Ideally this would have zoom capability to control image size.
Well there it is guys, how crazy is that?
CB.
Attachments
My only two comments are:
1- good luck finding a way to power all those lights without tripping a circuit breaker
2- good luck finding a cooling solution that won't drive you nuts because it's so noisy
Other than that, looks pretty cool 😎
1- good luck finding a way to power all those lights without tripping a circuit breaker
2- good luck finding a cooling solution that won't drive you nuts because it's so noisy
Other than that, looks pretty cool 😎
im a little confused... you want to use one color lcd panel with three light sources each pushing their own color? thats like putting three regular white lamps on one lcd panel....over powering if i say so...your black level will be nada....zilch...
when you mix red light, blue light and green light you get white light. so you'll be better off using one white lamp.
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here is an idea that i was toying with a few months ago, its basically the same idea as yours but using three 4" - 7" color panels set to monochrom (black) the colored light pushed through, collected in the prism, combined and pushed through to the lens.
i think, that with this design you dont have to use 250MH lamps , you can use 100W-150W because you have 3 lamps... maybe even high power automotive lamps. use the condenser lens from fog lamps and reflectors from for lamps or similar
ap0
when you mix red light, blue light and green light you get white light. so you'll be better off using one white lamp.
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here is an idea that i was toying with a few months ago, its basically the same idea as yours but using three 4" - 7" color panels set to monochrom (black) the colored light pushed through, collected in the prism, combined and pushed through to the lens.
i think, that with this design you dont have to use 250MH lamps , you can use 100W-150W because you have 3 lamps... maybe even high power automotive lamps. use the condenser lens from fog lamps and reflectors from for lamps or similar
ap0
Attachments
Thats my fault Apothiosis, No I just though that a person could unify the beams into one super point lightsource and then beam it at a normal LCD in the front. The diffrent colors was just to show the light path of the 3 same color light sources.
The Idea is to make a projector that can project say 20, 40 and 60k lumins depending on how many of the lamps you want to have on. I just want the prism to be used as a stage to combine and condition the light for projection onto the LCD stage. The prism chamber is surrounded on 3 sides (the ones where the lamps are) by IR/UV filter film. the thing in front is a fresnel.
The LCD is in front of that whole thing the square just makes all 3 lamps into a singl beam of very bright light. and because it is pre filtered before the prism it should help heep the LCD nice and cool.
And yeah I figured this would need about 4 fans in to keep it cool. Now the power draw is a matter that I wasnt really thinking about.
CB.
The Idea is to make a projector that can project say 20, 40 and 60k lumins depending on how many of the lamps you want to have on. I just want the prism to be used as a stage to combine and condition the light for projection onto the LCD stage. The prism chamber is surrounded on 3 sides (the ones where the lamps are) by IR/UV filter film. the thing in front is a fresnel.
The LCD is in front of that whole thing the square just makes all 3 lamps into a singl beam of very bright light. and because it is pre filtered before the prism it should help heep the LCD nice and cool.
And yeah I figured this would need about 4 fans in to keep it cool. Now the power draw is a matter that I wasnt really thinking about.
CB.
That was informative. 🙁
Care to tell me why not? I'm not saying you are wrong but really how was that post even worth the letters used in it. I guess if it is attempted and it doesnt work then you can say "I told you so", but beyond that what was that worth?
CB.
Care to tell me why not? I'm not saying you are wrong but really how was that post even worth the letters used in it. I guess if it is attempted and it doesnt work then you can say "I told you so", but beyond that what was that worth?
CB.
lol, yeah... these are just ideas... to inspire? i guess... best thing is to use one lcd and one light source with some good optics. anything else and you're just complicating things.
ap0
ap0
That was indeed the point, when I do get round to building a PJ, it will quite likely be from one of Alan's very practical MkII kits, so I do know the diffrence between an intresting mental exercise and a good and practical idea.
Is the idea over convoluted? Oh my god yes! But look on the bright side, I didnt ask a question or submit an idea that is posted 3-4 times a week.
What I was most interested in finding out was, what people here would think is the most problematic area of such a projector.
I agree 100-250 watt MH is probably going to wash out the image pretty badly, but what if those were lil 50 watt pin-spot MH tracklighting fixtures. Those are supposed to be pretty bright and cool for their size and power draw. I wonder about the idea of car headlamps too. A friend of mine asked me about them a few days back and I didnt figure it would work because I havent heard of anyone here doing it. Has anyone done that?
I heard a cool quote once, and I wish I knew who said it, but...
"A rational man adapts himself to suit his environment.
An irrational man adapts his environment to suit himself.
Thus all progress is dependant upon irrational men."
No offence intended toward anyone,
CB.
Is the idea over convoluted? Oh my god yes! But look on the bright side, I didnt ask a question or submit an idea that is posted 3-4 times a week.
What I was most interested in finding out was, what people here would think is the most problematic area of such a projector.
I agree 100-250 watt MH is probably going to wash out the image pretty badly, but what if those were lil 50 watt pin-spot MH tracklighting fixtures. Those are supposed to be pretty bright and cool for their size and power draw. I wonder about the idea of car headlamps too. A friend of mine asked me about them a few days back and I didnt figure it would work because I havent heard of anyone here doing it. Has anyone done that?
I heard a cool quote once, and I wish I knew who said it, but...
"A rational man adapts himself to suit his environment.
An irrational man adapts his environment to suit himself.
Thus all progress is dependant upon irrational men."
No offence intended toward anyone,
CB.
There is infact a CRT projector that is exaclty the same (except uses crts instead of lcds and bulbs of course 🙂 )
Here it is here
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3034662362&category=1499
The problem with these is that the prism cuts down a lot of the light, so what started as a very bright light will be significantly reduced by as much as 50%. Of course, 50% of 60k Lumens is still more than 1 20k Lumen bulb. The next problem is that you would have to converge the three light sources, I'm not sure that can even be done manually... I'm fairly certain you would need to build a circuit to aid in that.. I also think you would run into focusing issues, the three lcd's would have to be aligned perfectly.
As far as running on one circuit breaker, that shouldn't be a problem as most breakers are 15A and through some math (I=P/V) 3 250W MH bulbs would only draw 6.25A. Cooling also wouldn't be a huge problem, something this large would definetly have to be ceiling mounted, making it out of the way. You could also create a hush box to go around it... So... in theory, it could work.. but for the amount of money you would be spending you're better off buying a decent LCD or CRT.
Here it is here
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3034662362&category=1499
The problem with these is that the prism cuts down a lot of the light, so what started as a very bright light will be significantly reduced by as much as 50%. Of course, 50% of 60k Lumens is still more than 1 20k Lumen bulb. The next problem is that you would have to converge the three light sources, I'm not sure that can even be done manually... I'm fairly certain you would need to build a circuit to aid in that.. I also think you would run into focusing issues, the three lcd's would have to be aligned perfectly.
As far as running on one circuit breaker, that shouldn't be a problem as most breakers are 15A and through some math (I=P/V) 3 250W MH bulbs would only draw 6.25A. Cooling also wouldn't be a huge problem, something this large would definetly have to be ceiling mounted, making it out of the way. You could also create a hush box to go around it... So... in theory, it could work.. but for the amount of money you would be spending you're better off buying a decent LCD or CRT.
Now there is a constructive critique of my goofy freakin idea.
Light loss was somthing I hadnt thought of really as significant to the whole thing though, 50% loss from a prism that is used in projectors? Thats pretty bad, the image from the 3 color process must be pretty damn good for folks to but a projector that can only push say 5% of its light through and onto a wall.
Maybe I misunderstood the prism system, But for the 3 LCD system you would loose light from each reflective filter, each mirror, and probably huge amounts of light are lost in each of the 3 LCDs. Then to end it all with a further 50% loss from each of the 3 lamp colors.
My god what a mess, MkII sure looks good compared to all that.
CB.
Light loss was somthing I hadnt thought of really as significant to the whole thing though, 50% loss from a prism that is used in projectors? Thats pretty bad, the image from the 3 color process must be pretty damn good for folks to but a projector that can only push say 5% of its light through and onto a wall.
Maybe I misunderstood the prism system, But for the 3 LCD system you would loose light from each reflective filter, each mirror, and probably huge amounts of light are lost in each of the 3 LCDs. Then to end it all with a further 50% loss from each of the 3 lamp colors.
My god what a mess, MkII sure looks good compared to all that.
CB.
Yeah, 50% does seem a little high when I think about it now, that was a morning post, my bad 🙂 I just asked the crt forum over on avsforums.com for an approximation.. I'll get back to you on around how much light would be toast...
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