ChuckReese
Focal length is the distance it takes for parallel light to be converged to a point(or image). If you put the two ferensl lenses together it will have a 6" focal length. But you are right that it will take 24" to go from a point light to a point convergence. but in order to make the light parallel through the two lenses the light source would have to be at 6".
hope that helps
Focal length is the distance it takes for parallel light to be converged to a point(or image). If you put the two ferensl lenses together it will have a 6" focal length. But you are right that it will take 24" to go from a point light to a point convergence. but in order to make the light parallel through the two lenses the light source would have to be at 6".
hope that helps
ChuckReese,
to determine the focal length let the sun shine through and measure the distance to the focal point.
In the meantime i doubt, that the fresnels really have 12".
and, it doesn't matter, if the gratings are only on one side, impotant is only focal lenght. One sided means a quasi planconvex lens.
xblocker
to determine the focal length let the sun shine through and measure the distance to the focal point.
In the meantime i doubt, that the fresnels really have 12".
and, it doesn't matter, if the gratings are only on one side, impotant is only focal lenght. One sided means a quasi planconvex lens.
xblocker
tech_head...the mirrors at surplusshed are all relatively flat...Now I know they are selling spherical mirrors, but these are geared towards telescopes and are thus somewhat flat...They are part of a VERY large shpere (imaging having a 5 ft. sphere and just cutting out a small sectiion on the outer shell...thats what these do).
I would not be able to gather enough light...but thanks.
On a side note...I am frustrated...I did nothing on my projector this weekend and its been 2-3 weeks since I touched it. HOPEFULLY I have most of this week to work on it.
Good luck everyone...
Dave
I would not be able to gather enough light...but thanks.
On a side note...I am frustrated...I did nothing on my projector this weekend and its been 2-3 weeks since I touched it. HOPEFULLY I have most of this week to work on it.
Good luck everyone...
Dave
remp: i think your suggested reflector might actually work pretty well, upon further thought. i was thinking only the light coming off directly perpendicular to the light would go where we wanted, but there should be a decent arc of acceptability. having an adjustable stop would be nice, you could trade off between crispness and brightness. no clue how it'd be made though.
congradulations on your sucess.
piguy: the reflector your thinking of is parabolic. sphericals reflect light back to the center. think about it. if a light were in the middle of a sphere, all the light would be reflected right back to where it came. spherical mirrors just use a part of the sphere.
marklar: can you link or name this GE light? the size of these 400 w mh's is getting cumbersome.
prjctr_builder: i'm one of the numerous people who built a successful one, and as far as i know i've been one of the few people successful in tearing myself away from projector long enough to keep posting. to everyone else who fought the battle and is still here, go you.
please dont ever use all caps again. i hate it when people scream.
chuckreese: the problem with the light you listed (with reflector) is that the reflector is too small. the reflectors were dealing with are huge by comparison, they have to be, were using them as the sole element to put the light through the LCD, and thus they need to be as big as the LCD, or bigger. there are some decent resolution LCD's under 4mm in size, but they're very very expensive.
undream: go plas-tex. soon as i get some cash, i'm buying a whole boatload of it. might have to make a road trip to get it though, dont know if its stocked in metro area. i figure a road trip'll probably be cheaper than ordering it, given how many sheets i want (4).
myren
congradulations on your sucess.
piguy: the reflector your thinking of is parabolic. sphericals reflect light back to the center. think about it. if a light were in the middle of a sphere, all the light would be reflected right back to where it came. spherical mirrors just use a part of the sphere.
marklar: can you link or name this GE light? the size of these 400 w mh's is getting cumbersome.
prjctr_builder: i'm one of the numerous people who built a successful one, and as far as i know i've been one of the few people successful in tearing myself away from projector long enough to keep posting. to everyone else who fought the battle and is still here, go you.
please dont ever use all caps again. i hate it when people scream.
chuckreese: the problem with the light you listed (with reflector) is that the reflector is too small. the reflectors were dealing with are huge by comparison, they have to be, were using them as the sole element to put the light through the LCD, and thus they need to be as big as the LCD, or bigger. there are some decent resolution LCD's under 4mm in size, but they're very very expensive.
undream: go plas-tex. soon as i get some cash, i'm buying a whole boatload of it. might have to make a road trip to get it though, dont know if its stocked in metro area. i figure a road trip'll probably be cheaper than ordering it, given how many sheets i want (4).
myren
Myren...like I mentioned before the Plat-tex stuff is pretty sweet. You should be able to get it at almost any lowes or HomeDepot. I live in Pasadena (basically L.A.) and it is availble a a number of places within 15 miles from me.
What I did was I just got the UPC code and called to ask how many they had in stock. If you try to explain the name or what it is you will NEVER (not yelling...I emphasizing hehhehe) find anyone that has a clue. Just get the part number from the AVS link I posted a while back (probably 10 pages). The part number is on the second page of the discussion I think.
I heard you (maybe someone else) talk about getting a bunch of these and glueing them together. I really dont think this is going to be your best bet. No matter what you do I can not imagine that you are going to be able to mask the seam. If you caulk them together with white glue/caulk and move them tightly together I still have to believe you will notice it. Maybe not when the projector is off, but when you are projecting the caulk will have a different gain and reflective capabilities.
If you are planning on painting these with paint or the goosystem stuff then you dont need to wast your time with the plas-tex because you will be painting right over what makes this stuff soooo good.
So...if you do go that route pleeeeez let me know how it works out, because if it works nicely for you I am going a very similar route. If you are planning on something else I would like to hear details if you care to share.
What I did was I just got the UPC code and called to ask how many they had in stock. If you try to explain the name or what it is you will NEVER (not yelling...I emphasizing hehhehe) find anyone that has a clue. Just get the part number from the AVS link I posted a while back (probably 10 pages). The part number is on the second page of the discussion I think.
I heard you (maybe someone else) talk about getting a bunch of these and glueing them together. I really dont think this is going to be your best bet. No matter what you do I can not imagine that you are going to be able to mask the seam. If you caulk them together with white glue/caulk and move them tightly together I still have to believe you will notice it. Maybe not when the projector is off, but when you are projecting the caulk will have a different gain and reflective capabilities.
If you are planning on painting these with paint or the goosystem stuff then you dont need to wast your time with the plas-tex because you will be painting right over what makes this stuff soooo good.
So...if you do go that route pleeeeez let me know how it works out, because if it works nicely for you I am going a very similar route. If you are planning on something else I would like to hear details if you care to share.
Myren, and anyone else....the sku for the parkland plas-tex screen is:
637553000012
Later,
Dave
637553000012
Later,
Dave
ChuckReese,
i have to correct one point. The distance between the lightsource and fresnels should not be 6", but around 12" to get the lightsource imaged on the other side at the same distance. Then you should get 2 symmetrical light cones the first diverging to fresnels, and the second converging to projection lens plane.
Good luck!
xblocker
i have to correct one point. The distance between the lightsource and fresnels should not be 6", but around 12" to get the lightsource imaged on the other side at the same distance. Then you should get 2 symmetrical light cones the first diverging to fresnels, and the second converging to projection lens plane.
Good luck!
xblocker
Xblocker
My projector setup does work. I don't say things work if they don't. But note the words in my first sentance "it is terrible".
Basically I just used a slide projector as a backlight and a fresnel as a projecting lens. As you can imagine the fresnel does not make a very good projection lens but never mind. At least I now have a terrible projector which I will improve.
I did notice something if anyone is interested. As mentioned the writing was reversed. I turned the LCD panel around so the front of the panel faced the slide projector. The writing was now the correct way but for some reason the picture quality improved quite noticably. Dont know why. There was no risk of burning the panel because as mentioned the light from the slide projector contained no disernable heat. Just shows you eh the things you find out.
My projector setup does work. I don't say things work if they don't. But note the words in my first sentance "it is terrible".
Basically I just used a slide projector as a backlight and a fresnel as a projecting lens. As you can imagine the fresnel does not make a very good projection lens but never mind. At least I now have a terrible projector which I will improve.
I did notice something if anyone is interested. As mentioned the writing was reversed. I turned the LCD panel around so the front of the panel faced the slide projector. The writing was now the correct way but for some reason the picture quality improved quite noticably. Dont know why. There was no risk of burning the panel because as mentioned the light from the slide projector contained no disernable heat. Just shows you eh the things you find out.
Myren said:
I suggested these reflectors because they allow you get the most of the light concentrated to a small (2-4 mm) spot. I am fully aware you would still need a condenser lens, but at least you get a decent metal halide that is a point source.
Something else I forgot to mention... the Solarc bulbs (marketspeak for their metal halide technology) have a very short arc gap so they can focused to a small spot. Combine a short arc gap with an elliptical reflector and you get a point source. The LM60 can put 1000 lumens through a 4mm spot.
These source are are really tiny. The bulb module measures 80mm x 70mm x 70mm. The ballast measures 60mm x 60mm x 30mm.
CR
Photos and progress!
I said earlier that I got the 250W MH thats only rated at like 10,000 lumens here are some pics of some ideas and my progress.
Here you can see I just wraped foil around the bulb this is only temp unless it really works on the big bulb I then used a normal maginifing glass to spread the beam onto the mirror.
There is just a small hole in the foil for the light to come out and the bulb is in a sealed area it does have a large fan to keep from burning up I had it on for about 2 hours to see what would happen the only part that got real hot was the top door cause its touching it. The new bulb Im getting is going to be smaller so I won't have to worry about that.
looks like a normal OHP setup Im going to stick with this until I get it working properly then I will build a nice case for it all to fit in to keep all the light from shining out.
I put a paper plate under the projection lens and you can see the shape of the arc tube its not a point of light its a rectangle about 1 inch X 3inches
This is my plan on how to make the focus point an even square so it will light up the LCD panel evenly.
This is about 6 foot from the projector.
This is about 17 foot from the projector the room had to be very dark to see the image there is no way this bulb could make a visiable image in low lighting conditions.
I said earlier that I got the 250W MH thats only rated at like 10,000 lumens here are some pics of some ideas and my progress.
An externally hosted image should be here but it was not working when we last tested it.
Here you can see I just wraped foil around the bulb this is only temp unless it really works on the big bulb I then used a normal maginifing glass to spread the beam onto the mirror.
An externally hosted image should be here but it was not working when we last tested it.
There is just a small hole in the foil for the light to come out and the bulb is in a sealed area it does have a large fan to keep from burning up I had it on for about 2 hours to see what would happen the only part that got real hot was the top door cause its touching it. The new bulb Im getting is going to be smaller so I won't have to worry about that.
An externally hosted image should be here but it was not working when we last tested it.
looks like a normal OHP setup Im going to stick with this until I get it working properly then I will build a nice case for it all to fit in to keep all the light from shining out.
An externally hosted image should be here but it was not working when we last tested it.
I put a paper plate under the projection lens and you can see the shape of the arc tube its not a point of light its a rectangle about 1 inch X 3inches
An externally hosted image should be here but it was not working when we last tested it.
This is my plan on how to make the focus point an even square so it will light up the LCD panel evenly.
An externally hosted image should be here but it was not working when we last tested it.
This is about 6 foot from the projector.
An externally hosted image should be here but it was not working when we last tested it.
This is about 17 foot from the projector the room had to be very dark to see the image there is no way this bulb could make a visiable image in low lighting conditions.
Hi all!!!
I finally got all my funds in place and now i am very much ready to START where i left off. I have a whole notebook of drawings and calculations, hehe....
Anyway, MYREN, you said that you have built a projector successfully, what kind of design did you use? The overhead type or stratight in line?
The reason that i want to make a projector is that i want to run FLIGHT SIMULATOR 2002 on it. i think that it will look very good in the wall.
I think that i am going to use a 17" ViewSonic LCD monitor as my LCD screen, and try to build it in a straight line design....hehe
But before i insert an LCD in there,i just want ro make a really bright projector, and then try to focus it.
ok, just updating you...hehe
aleksey
I finally got all my funds in place and now i am very much ready to START where i left off. I have a whole notebook of drawings and calculations, hehe....
Anyway, MYREN, you said that you have built a projector successfully, what kind of design did you use? The overhead type or stratight in line?
The reason that i want to make a projector is that i want to run FLIGHT SIMULATOR 2002 on it. i think that it will look very good in the wall.
I think that i am going to use a 17" ViewSonic LCD monitor as my LCD screen, and try to build it in a straight line design....hehe
But before i insert an LCD in there,i just want ro make a really bright projector, and then try to focus it.
ok, just updating you...hehe
aleksey
Richard,
ok, working is a relative term. All is working anyhow, for me working means to do the job. But if the panel works this is most important.
Did you find a setup menu where you can adjust projection parameters? How is the image improved projecting the 'wrong' side? I would say there's a lot to improve in your actual assembly, but you know it yourself.
Welcome in the Pixelfriends club!!
Good luck !
xblocker
ok, working is a relative term. All is working anyhow, for me working means to do the job. But if the panel works this is most important.
Did you find a setup menu where you can adjust projection parameters? How is the image improved projecting the 'wrong' side? I would say there's a lot to improve in your actual assembly, but you know it yourself.
Welcome in the Pixelfriends club!!
Good luck !
xblocker
Aleksey,
could it be that we all experience a big surprise, if you have finished your flight simulator training....Hehe ?
Seriously, 17" has of course great resolution, but is way to big to get affordable parts for it, especialy condensors, and you would need projection lens with focal lenght more then 17". This projector will be a huge chickenhouse,,,hehe!!
xblocker
could it be that we all experience a big surprise, if you have finished your flight simulator training....Hehe ?
Seriously, 17" has of course great resolution, but is way to big to get affordable parts for it, especialy condensors, and you would need projection lens with focal lenght more then 17". This projector will be a huge chickenhouse,,,hehe!!
xblocker
Xblocker
Not a lot to improve. Just picture quality, colour, more light, I spent all night looking for 12 inch lens no luck but did find surplus site with lots of lenses
www.goldmine-elec.com
No can find the text reverse. Must be computer controlled. There is a menu. Its no problem at the moment.
Picture improved when panel reversed by more light through. Better colour and page magnifier not nearly so critical in position.
Could be the panel is made to accomodate angle in light it would get when sitting on an OHP.
Not a lot to improve. Just picture quality, colour, more light, I spent all night looking for 12 inch lens no luck but did find surplus site with lots of lenses
www.goldmine-elec.com
No can find the text reverse. Must be computer controlled. There is a menu. Its no problem at the moment.
Picture improved when panel reversed by more light through. Better colour and page magnifier not nearly so critical in position.
Could be the panel is made to accomodate angle in light it would get when sitting on an OHP.
Richard,
why not improvise with 2 eyeglasses, each with about 600 mm. So you get a projection lens with f=300mm. Eye glasses are better than planconvex lenses because of less spherical aberation. The formula of dioptrics: dpt=1/f. I got a lot of glasses for 0-Bucks !
xblocker
why not improvise with 2 eyeglasses, each with about 600 mm. So you get a projection lens with f=300mm. Eye glasses are better than planconvex lenses because of less spherical aberation. The formula of dioptrics: dpt=1/f. I got a lot of glasses for 0-Bucks !
xblocker
XBLOCKER!!!!
i dunno, but i think that i will use a projector headlgihts ( from a car) as a light source. It has a condenser lence installed, and spreads light evenly.
as to the size, i have a 3 car garage, lmao..... all i want is to make the image appear on the wall, and then try to modify it and make it smaller.
i am pobably going to buy a PROXIMA 842 projecton panel from ebay.com, just in case it will take time to get the monitor and take it apart. i am anxious to start.
Tell me what you think.
P.S. don't tell me car headlights produce a lot of heat, because i WILL remove it, after all i have a head on my shoulders for some reason, it may be useful now.
i dunno, but i think that i will use a projector headlgihts ( from a car) as a light source. It has a condenser lence installed, and spreads light evenly.
as to the size, i have a 3 car garage, lmao..... all i want is to make the image appear on the wall, and then try to modify it and make it smaller.
i am pobably going to buy a PROXIMA 842 projecton panel from ebay.com, just in case it will take time to get the monitor and take it apart. i am anxious to start.
Tell me what you think.
P.S. don't tell me car headlights produce a lot of heat, because i WILL remove it, after all i have a head on my shoulders for some reason, it may be useful now.
Myren , GunawanD
Maybe worth a call, I might get lucky.
I may delve into some of the ebay virtual glasses soon:
Sony's 700 Glasstron has 800xRGBX600 0.7" x2 color panels (~$700)! The 50-55's have 800xRGBx234 (still great for wide screen- DVD! 100-300$). Can't get any spec's on these like contrast. But, could be a way to pick up some small hi-res lcd's for a projector.
.....THAT'S IT! To tread further, is to contemplate the sound of one hand clapping:
GunawanD: Saya e-mel anda pada masa sekarang. Beberapa maklumat sangat rahsia! Tidak seorang pun dapat memahami, ha-ha-ha! I am always joking! Jantung sedih, saya mempunyai. he-he....1,000,000 lumens?! Wow!....Mereka tidak memahami....Cuaca bagaimana? Is it really THAT secretive!?!...Saya menganggap mereka sebagai semua percubaan gila sekarang!...Okay, be careful with the plutonium!...Kami ketawa sedemikian keras sekarang. Ha-ha-ha!
Don't get the I-visor or Cy-visor unless you want to go the reflective way. Which seems troublesome for me at this point since it requires three (RGB) light sources and their timing and modulating mechanism's.
But, this may well be the best technology has to offer currently, as one of the JVC model's with reflective panels has impressed some journalists' into saying it appears as good as "35 mm print"!
They are really great with color saturation and contrast. Problem is, they require twice as much wattage to get the same lumens out, as transmissive do.
Still, cheaper (per lumen) than the BEST the other technology's have to offer, though! Lokost is working with one now in addition to his large panel. If he can DIY the lighting req's that could be a smaller portable hi-res (svga,xga,sxga) alternative.
Maybe worth a call, I might get lucky.
I may delve into some of the ebay virtual glasses soon:
Sony's 700 Glasstron has 800xRGBX600 0.7" x2 color panels (~$700)! The 50-55's have 800xRGBx234 (still great for wide screen- DVD! 100-300$). Can't get any spec's on these like contrast. But, could be a way to pick up some small hi-res lcd's for a projector.
.....THAT'S IT! To tread further, is to contemplate the sound of one hand clapping:
GunawanD: Saya e-mel anda pada masa sekarang. Beberapa maklumat sangat rahsia! Tidak seorang pun dapat memahami, ha-ha-ha! I am always joking! Jantung sedih, saya mempunyai. he-he....1,000,000 lumens?! Wow!....Mereka tidak memahami....Cuaca bagaimana? Is it really THAT secretive!?!...Saya menganggap mereka sebagai semua percubaan gila sekarang!...Okay, be careful with the plutonium!...Kami ketawa sedemikian keras sekarang. Ha-ha-ha!
Don't get the I-visor or Cy-visor unless you want to go the reflective way. Which seems troublesome for me at this point since it requires three (RGB) light sources and their timing and modulating mechanism's.
But, this may well be the best technology has to offer currently, as one of the JVC model's with reflective panels has impressed some journalists' into saying it appears as good as "35 mm print"!
They are really great with color saturation and contrast. Problem is, they require twice as much wattage to get the same lumens out, as transmissive do.
Still, cheaper (per lumen) than the BEST the other technology's have to offer, though! Lokost is working with one now in addition to his large panel. If he can DIY the lighting req's that could be a smaller portable hi-res (svga,xga,sxga) alternative.
OK
Today i went to the auto parts store....
-Hi, do you have projector headlights?
-No
-do you know where i can get them?
-Probably Home Depot
-do you have anything else that may be as bright?
-Check on the shelf, there's everyhting we've got...
-i need projector lights because they have condenser lenses on them installed.
-what are the con-cond-condenser lenses...hehe
-ok never mind!!!
guess i have to go to Home Depot to try my luck out.
Aleksey
Today i went to the auto parts store....
-Hi, do you have projector headlights?
-No
-do you know where i can get them?
-Probably Home Depot
-do you have anything else that may be as bright?
-Check on the shelf, there's everyhting we've got...
-i need projector lights because they have condenser lenses on them installed.
-what are the con-cond-condenser lenses...hehe
-ok never mind!!!
guess i have to go to Home Depot to try my luck out.
Aleksey
Bought a larger page viewer today for my setup. Nealy gives the whole screen. Much better than the old one I was using. With the front of the panel facing backwards and the new page viewer the picture is just about showing pixelation so resolution is definitely improving. Also took my panel down to friendly lighting shop to put on 3m OHP. 2000 lumen model. Manager tried setup in shop with full lighting no good. He suggested we try in staff lunchroom. No curtains on windows but overcast day. Not bad illumination on 6 foot wide picture of panel opening screen. I have to go back tommorow with test video tape.
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