comprehensive instructions?
I'll have to admit... I havn't read ALL pages of this thread, but it does seem quite interesting. Are there any comprehensive instructions how to do all this? And actually how good is the quality... I mean can one actually be made to out perform retail products?
I'll have to admit... I havn't read ALL pages of this thread, but it does seem quite interesting. Are there any comprehensive instructions how to do all this? And actually how good is the quality... I mean can one actually be made to out perform retail products?
With lcd panels(the kind that sits on overhead projector) on ebay some say 185,000 true colors or 2 million colors. So to display dvd's and pc through it correctly what should be the minimum panel (color wise) I get?
really busy right now, so i can only offer a couple real quick responses to a fraction of the posts i'd like to reply to. more in depth post tomorrow.
first off, final image size is totally independent of lcd panel size. you could be using a half inch LCD panel and have your final image be thirty feet wide. it just depends on the optics. realistically though, your probably not going to get as much light because the smaller panel has a smaller % of the light going through it. plus your typically not going to have as many pixels on a smaller panel, so the final image will be granier than with a larger panel. its all an issue of balance though. i really wish i could offer up some sort of comparison, but having never seen any of the 5 inch panel systems in motion, i'm unable to do so.
sometime springtime my friend'll be back with his portable 3" LCD based TV. it'll be interesting to disect that for comparison purposes. thats a ways off though.
again, i cant say this enough, remember the fundamnetal law of thermodyamics: entropy is the irreversible process. those uv filters are great, but just remember that they are not a substitute for fans. they simply reflect heat from going a certain direction, they dont inherently get rid of the heat, just move it around.
i really dont know what the deal is with the overhead projection panels. the only ones i've seen really sucked, but then again i havent seen one for at least two years. just make sure its got a contrast ratio of 300:1 or better and an acceptable resolution.
axeman: theres little plastic stoppers over the screw holders on the rad5. at least there are on my room mates. its got a contrast ratio of 300:1, which is respectable.
ryans: when i get my LCD monitor back, i'm going to take photos of the disassembly thereof, plus the minor mounting panel to projector part to. should be pretty comprehensive. quality, by the way, is purely a function of the projector and panel you buy. i'm thinking of spending $4000 for a projector that should beat the pants off a good deal of the $25,000 projectors (real 1080p plus over 6000 lumens).
first off, final image size is totally independent of lcd panel size. you could be using a half inch LCD panel and have your final image be thirty feet wide. it just depends on the optics. realistically though, your probably not going to get as much light because the smaller panel has a smaller % of the light going through it. plus your typically not going to have as many pixels on a smaller panel, so the final image will be granier than with a larger panel. its all an issue of balance though. i really wish i could offer up some sort of comparison, but having never seen any of the 5 inch panel systems in motion, i'm unable to do so.
sometime springtime my friend'll be back with his portable 3" LCD based TV. it'll be interesting to disect that for comparison purposes. thats a ways off though.
again, i cant say this enough, remember the fundamnetal law of thermodyamics: entropy is the irreversible process. those uv filters are great, but just remember that they are not a substitute for fans. they simply reflect heat from going a certain direction, they dont inherently get rid of the heat, just move it around.
i really dont know what the deal is with the overhead projection panels. the only ones i've seen really sucked, but then again i havent seen one for at least two years. just make sure its got a contrast ratio of 300:1 or better and an acceptable resolution.
axeman: theres little plastic stoppers over the screw holders on the rad5. at least there are on my room mates. its got a contrast ratio of 300:1, which is respectable.
ryans: when i get my LCD monitor back, i'm going to take photos of the disassembly thereof, plus the minor mounting panel to projector part to. should be pretty comprehensive. quality, by the way, is purely a function of the projector and panel you buy. i'm thinking of spending $4000 for a projector that should beat the pants off a good deal of the $25,000 projectors (real 1080p plus over 6000 lumens).
Myren,
Thanks for pointing out the thermo laws for the UV filter. I was thinking that this UV filter could be used with a high power point-source light and a physical barrier lens to create a "hot box" that would greatly reduce the amount of heat that the LCD receives. Of course, it would need adequate ventilation. Are there any UV filter lenses with heatsinks? I think some of the "cold mirrors" have heatsinks that help dissipate the heat.
I know that this idea has probably been brought up many times. There are 742 posts in this thread! Too bad they aren't categorized into different topics that can be searched. Oh well...
skilzygw,
I don't have any experience with those panels, but it seems like 185,000 colors would produce a decent picture. Of course, more would be better, but at least it's not 256 or grayscale🙂
-f4
Thanks for pointing out the thermo laws for the UV filter. I was thinking that this UV filter could be used with a high power point-source light and a physical barrier lens to create a "hot box" that would greatly reduce the amount of heat that the LCD receives. Of course, it would need adequate ventilation. Are there any UV filter lenses with heatsinks? I think some of the "cold mirrors" have heatsinks that help dissipate the heat.
I know that this idea has probably been brought up many times. There are 742 posts in this thread! Too bad they aren't categorized into different topics that can be searched. Oh well...
skilzygw,
I don't have any experience with those panels, but it seems like 185,000 colors would produce a decent picture. Of course, more would be better, but at least it's not 256 or grayscale🙂
-f4
Cold mirror
i was searching for a place to get a cold mirror here in Australia, and i stumbled across this website and it mentions the cooling system in the IMAX projector -
"Normal projector lamp houses were just not sufficient for the large screen sizes envisaged, and the illumination finally selected was a 12kW water cooled Xenon lamp developed by the US military for its searchlights. Although the light output was sufficient for the IMAX projector, the amount of heat generated was enough to cause a 2Õ x 4Õ piece of wood held at or near the film plane to burst into flames! Bill Shaw's solution was a water cooled metal mirror behind the lamp as a heat sink to absorb infrared and a supplementary 'cold' mirror made of quartz, coated to pass infra-red."
whch makes me think, if i (or whoever) were able to make a mirror finish waterblock - most likely a piece of lapped stainless steel, i could use that to cool the beam of light. maybe. any suggestions?
i was searching for a place to get a cold mirror here in Australia, and i stumbled across this website and it mentions the cooling system in the IMAX projector -
"Normal projector lamp houses were just not sufficient for the large screen sizes envisaged, and the illumination finally selected was a 12kW water cooled Xenon lamp developed by the US military for its searchlights. Although the light output was sufficient for the IMAX projector, the amount of heat generated was enough to cause a 2Õ x 4Õ piece of wood held at or near the film plane to burst into flames! Bill Shaw's solution was a water cooled metal mirror behind the lamp as a heat sink to absorb infrared and a supplementary 'cold' mirror made of quartz, coated to pass infra-red."
whch makes me think, if i (or whoever) were able to make a mirror finish waterblock - most likely a piece of lapped stainless steel, i could use that to cool the beam of light. maybe. any suggestions?
wait a second
no, i take it back. i don't think that would work all that well actually. a small waterblock attached to the back of a cold mirror would be better. just a thought anyway
no, i take it back. i don't think that would work all that well actually. a small waterblock attached to the back of a cold mirror would be better. just a thought anyway
Hmmmm??
I've gotta say people, this thread just keeps getting more interesting everytime I read it.
I've been doing a few experiments with boxes lights and optics and as yet, though I've learnt a lot of things I have yet to find myself a suitable setup, with this in mind I have managed to refrain from buying any expensive LCD screens.
The main problem still seems to be size, I really want something quite small and light, I've currently got a big SONY crt projector which I bought off my university dept several years ago (for well onder £500), I've had enough of it now and storing it is a nightmare, so if anyone in the uk wants to come and buy it off me so I can fund some more experiments into my diy projector come on down, I'll happily let you have it for £250 if you come and get it. The thing is it weighs 65kg (Ouch!!). Sorry for my little sales pitch but I just wanted to tell everyone that I need my big screen back and a portable one too. Having watched Event Horizon on a screen with a 5 METRE diagonal I just have trouble with the 29" in my room now.
Keep it up eveyone
Nick.
I've gotta say people, this thread just keeps getting more interesting everytime I read it.
I've been doing a few experiments with boxes lights and optics and as yet, though I've learnt a lot of things I have yet to find myself a suitable setup, with this in mind I have managed to refrain from buying any expensive LCD screens.
The main problem still seems to be size, I really want something quite small and light, I've currently got a big SONY crt projector which I bought off my university dept several years ago (for well onder £500), I've had enough of it now and storing it is a nightmare, so if anyone in the uk wants to come and buy it off me so I can fund some more experiments into my diy projector come on down, I'll happily let you have it for £250 if you come and get it. The thing is it weighs 65kg (Ouch!!). Sorry for my little sales pitch but I just wanted to tell everyone that I need my big screen back and a portable one too. Having watched Event Horizon on a screen with a 5 METRE diagonal I just have trouble with the 29" in my room now.
Keep it up eveyone
Nick.
Watercooling
Hi All.
Recently I have been lurking through these forums and rediscovered this thread. Its great that so much progress has been made.
Anyway, I have noticed alot of people complaining about heat issues. Coming from an overclockering forum (www.overclockers.com.au) the first thought that struck me was watercooling.
Watercooling is cheap, quiet and water is capable of transferring an enormous amount of energy away a system.
I am not a watercooler myself, however if you head over to the Overclockers Australia forums at http://forums.overclockers.com.au there is an Extreme Cooling forum in which many people would be pleased to offer suggestions if you explained exactly what you want to acheive.
Hi All.
Recently I have been lurking through these forums and rediscovered this thread. Its great that so much progress has been made.
Anyway, I have noticed alot of people complaining about heat issues. Coming from an overclockering forum (www.overclockers.com.au) the first thought that struck me was watercooling.
Watercooling is cheap, quiet and water is capable of transferring an enormous amount of energy away a system.
I am not a watercooler myself, however if you head over to the Overclockers Australia forums at http://forums.overclockers.com.au there is an Extreme Cooling forum in which many people would be pleased to offer suggestions if you explained exactly what you want to acheive.
Assailant
Hello
I live in Australia as well Assailant, where do you live?I also work for IMAX, and yes that is true about the cooling, althought it LOUD! I like the Idea of a UV filter, fender4 that is not what we need, it is the heat absorbing glass that edmund optics sell that we need, well I am starting work on modifying my OHP, I am cuttin out a huge section of the back, mounting a mirror inside that is on a 45 degree angle and building a lamp housing on the back, if you think about it OHP sre not good with heat becuase heat rises and so heat goes straight to the fresnel, no in my system though! Will tell you how it goes!
Hello
I live in Australia as well Assailant, where do you live?I also work for IMAX, and yes that is true about the cooling, althought it LOUD! I like the Idea of a UV filter, fender4 that is not what we need, it is the heat absorbing glass that edmund optics sell that we need, well I am starting work on modifying my OHP, I am cuttin out a huge section of the back, mounting a mirror inside that is on a 45 degree angle and building a lamp housing on the back, if you think about it OHP sre not good with heat becuase heat rises and so heat goes straight to the fresnel, no in my system though! Will tell you how it goes!
Rad5 no good?
Myren-
The plastic stoppers worry me. Does this mean that there is no way for me to open it up without it being really obvious? That would definately be bad. Where did you get your viewsonic panel, and for how much? I read some really good reviews of the rad5 claiming fast pixel response(which has been one of my big concerns) and a clear picture, however. EarthLCD has some fairly cheap 14" panels, but I don't know about response time/contrast, etc. Looks like I'll have to do some more searching.. 🙁
Myren-
The plastic stoppers worry me. Does this mean that there is no way for me to open it up without it being really obvious? That would definately be bad. Where did you get your viewsonic panel, and for how much? I read some really good reviews of the rad5 claiming fast pixel response(which has been one of my big concerns) and a clear picture, however. EarthLCD has some fairly cheap 14" panels, but I don't know about response time/contrast, etc. Looks like I'll have to do some more searching.. 🙁
Driving White LED's
I found a great web presentation (multimedia audio + slides) about driving white LEDs. It gives lots of information about getting equal light levels out of each LED.
It also talks about who makes the brightest devices for miniature devices like cell phones and for large devices, like signs.
National Semiconductor: Differentiate Mobile Devices with White
LED Driver Solutions from National
http://seminar2.techonline.com/~nsc22/jan1702/
I found a great web presentation (multimedia audio + slides) about driving white LEDs. It gives lots of information about getting equal light levels out of each LED.
It also talks about who makes the brightest devices for miniature devices like cell phones and for large devices, like signs.
National Semiconductor: Differentiate Mobile Devices with White
LED Driver Solutions from National
http://seminar2.techonline.com/~nsc22/jan1702/
lcd computer screen , uv filter
skilzygw :
DVI output is not a parallel output, but a serial one (maybe, but I don't know the protocol for the moment), so you cannot drive directly an LCD panel from a laptop 🙁 you'll need fast electonic (serial to parallel converter)
flat screen such as viesonic or LG is a good idea, it's a nice size for an OHP to get the maximum light, an you can drive it directly 😉
I don't wanna use that for the moment because it's a little bit expensive for me !
My 10.4 inches panel works fine on my OHP, but the contrast is not very good : 150:1 from the panel, and some reflections on the projection lense.
I didn't let it for a long time, but i think it will be a little bit too warm 🙁
50°C is the max recommended operation temperature for a LCD, and with dark pictures, it will become hotter.
I have to build a case (pastic, or wood) to protect my panel (I've already broke a ribbon connector, hapilly I've been able to solder it 😉
Moreover, the LCD won't be direrctlin over the fresnel lens, but I'll let about 1 inch to blow some cold air.
fender4 :
I don't understand why you are looking for UV filter. the heat problem is due to InfraRed, no ?
skilzygw :
DVI output is not a parallel output, but a serial one (maybe, but I don't know the protocol for the moment), so you cannot drive directly an LCD panel from a laptop 🙁 you'll need fast electonic (serial to parallel converter)
flat screen such as viesonic or LG is a good idea, it's a nice size for an OHP to get the maximum light, an you can drive it directly 😉
I don't wanna use that for the moment because it's a little bit expensive for me !
My 10.4 inches panel works fine on my OHP, but the contrast is not very good : 150:1 from the panel, and some reflections on the projection lense.
I didn't let it for a long time, but i think it will be a little bit too warm 🙁
50°C is the max recommended operation temperature for a LCD, and with dark pictures, it will become hotter.
I have to build a case (pastic, or wood) to protect my panel (I've already broke a ribbon connector, hapilly I've been able to solder it 😉
Moreover, the LCD won't be direrctlin over the fresnel lens, but I'll let about 1 inch to blow some cold air.
fender4 :
I don't understand why you are looking for UV filter. the heat problem is due to InfraRed, no ?
Ive checked out some controllers for laptop lcd's and they seem to be an average of 200 bucks. For that its just not worth it. I'd rather go panel or an lcd monitor and open it up...something like a 15inch viewsonic.
Hey I was wondering I see really cheap 4inch lcd's. Like the kind used for vans and cars to quite the kids. SO can that be used? They are relatively cheap average of 90 bucks.
I know its a smaller size but is it active matrix? How easy would it be to open that thing up? Basically these are backlit screens but we're supplying the light right?
Hey I was wondering I see really cheap 4inch lcd's. Like the kind used for vans and cars to quite the kids. SO can that be used? They are relatively cheap average of 90 bucks.
I know its a smaller size but is it active matrix? How easy would it be to open that thing up? Basically these are backlit screens but we're supplying the light right?
4" screens
I have a 4" TFT screen that I bought from Ebay, and I'm working on making a projector out of it. it's active matrix, and definately speedy enough for everything I've thrown at it(video games and movies). It's downfall is the resolution- only 383x234. but it does work well and has fairly good contrast.
I have a 4" TFT screen that I bought from Ebay, and I'm working on making a projector out of it. it's active matrix, and definately speedy enough for everything I've thrown at it(video games and movies). It's downfall is the resolution- only 383x234. but it does work well and has fairly good contrast.
Hmmm interesting.
Why are are we looking for contrast of 350:1 in lcd monitors. WHat exactly does the contrast due for us? Thanks.
Im asking because I've found a cheap 15inch lcd monitor but its contrast is 150:1 will this be unusable?
Thanks!
Why are are we looking for contrast of 350:1 in lcd monitors. WHat exactly does the contrast due for us? Thanks.
Im asking because I've found a cheap 15inch lcd monitor but its contrast is 150:1 will this be unusable?
Thanks!
with higher contrast, you can see more details, for exemple on dark clothes on a night movie, with low contrast, the scene looks like a big black part, but with higher contrast, you'll see the details
pask,
The UV filter might be the wrong approach. I was just basing this on a link Vince posted at the beginning of this thread: Sharp projector and Fiat1's post a few days ago (I hope it's ok if I quote you, Fiat1 🙂 )
Everything I know about optics I learned from this thread, so I'm sure I misunderstood some things along. PLEASE correct me if I am on the wrong track...I don't want to be the source of incorrect info! 😱
skilzygw,
The type of LCD you described (the small ones made for mobile video) can be used, just as zark has used a 5" one: Zark's website.
Several others are taking this approach, including myself. They probably wouldn't be as ideal as a projection panel for OHP, unless the large lighting surface was concentrated down to the size of the LCD. Otherwise, there would be a great deal of "wasted" light.
I personally like the idea of using small mobile LCD's because of their small size and low price. Of course, resolution is a drawback, but Zark has produced some impressive screenshots with his. The OHP approach seems to be better suited for high resolution setups, but the size of the actual projector will be fairly large.
Good luck, everybody!
-f4
The UV filter might be the wrong approach. I was just basing this on a link Vince posted at the beginning of this thread: Sharp projector and Fiat1's post a few days ago (I hope it's ok if I quote you, Fiat1 🙂 )
Everything I know about optics I learned from this thread, so I'm sure I misunderstood some things along. PLEASE correct me if I am on the wrong track...I don't want to be the source of incorrect info! 😱
skilzygw,
The type of LCD you described (the small ones made for mobile video) can be used, just as zark has used a 5" one: Zark's website.
Several others are taking this approach, including myself. They probably wouldn't be as ideal as a projection panel for OHP, unless the large lighting surface was concentrated down to the size of the LCD. Otherwise, there would be a great deal of "wasted" light.
I personally like the idea of using small mobile LCD's because of their small size and low price. Of course, resolution is a drawback, but Zark has produced some impressive screenshots with his. The OHP approach seems to be better suited for high resolution setups, but the size of the actual projector will be fairly large.
Good luck, everybody!
-f4
I opened up my 5.6" LCD and found out that instead of one set of ribbons that attach to the screen there are two, one on the bottom as in Zarks and one from the side, these are on two seprate boards with a very, very small ribbon cable connectiong then. I don't see any way to move them out of the way without some kind of extention cable. Just a warning for those who are looking into the smaller LCD's.
lcd contrast
Hello,
I was talking to one of the techs that builds the displays for our machines where I work, and he said that the higher the contrast of the screen, the less transmissive it is when its on, so you would need a brighter light behind it to reveal the detail.
Thanks,
Joel
Also, it seems that the thinner the module, the more likely that the driver is attatched at one side and can be moved aside more easily.
Hello,
I was talking to one of the techs that builds the displays for our machines where I work, and he said that the higher the contrast of the screen, the less transmissive it is when its on, so you would need a brighter light behind it to reveal the detail.
Thanks,
Joel
Also, it seems that the thinner the module, the more likely that the driver is attatched at one side and can be moved aside more easily.
major cooling bitches we've got:
first off, film has the advantage of being film. when a movie projector is rolling, each frame only gets blasted for what, 1/24 of a second or something? with the panels were using, we have no such luxury. we need serious freaking cooling to keep a single frame cool under constant usage.
stage techies seem to relish in 150 degree catwalks, and as such a lot of the stage bulbs we've been finding in our projectors produce excess amounts of heat.
there arent that many things we can cool directly. conventional cooling (as i think of it at least) usually doesnt involve optical elements. we cant just go around sticking on heat sinks and adding water coolers to everything (the quiet alternative to fans), as much as we'd like to.
overhead projectors put the heat source at the bottom of the system, which is possibly the worst place for it to be.
there are a number of potential ways to address these problems:
use better bulbs. in the past couple days i've become a huge proponent of metal halide high intensity discharge (hid) lights. damn these things rock. available anywhere between fifty and a thousand kilowatts, these are bar none the single most efficient light sources around. they require starter circuitry, but the 20,000 hour bulb life, low bulb cost and unsurpassed energy efficiency will more than make up for it. i'd suggest S.C.W.A metal halide high intensity discharge systems, which are a certain type of pulse start hid.
Assailant's suggestion of waterblocking cold mirrors sounds really top notch. finding cold mirrors for a reasonable price is a major pain in the *** though.
try to use convection as best as you can, dont fight it. smart placement of vents can help direct heat to where you want it to go, or more percisely, away from where you dont want it to go.
i had a lot more to say about this, but i've had my head crammed in so many optics books i forgot most of it.
myren
first off, film has the advantage of being film. when a movie projector is rolling, each frame only gets blasted for what, 1/24 of a second or something? with the panels were using, we have no such luxury. we need serious freaking cooling to keep a single frame cool under constant usage.
stage techies seem to relish in 150 degree catwalks, and as such a lot of the stage bulbs we've been finding in our projectors produce excess amounts of heat.
there arent that many things we can cool directly. conventional cooling (as i think of it at least) usually doesnt involve optical elements. we cant just go around sticking on heat sinks and adding water coolers to everything (the quiet alternative to fans), as much as we'd like to.
overhead projectors put the heat source at the bottom of the system, which is possibly the worst place for it to be.
there are a number of potential ways to address these problems:
use better bulbs. in the past couple days i've become a huge proponent of metal halide high intensity discharge (hid) lights. damn these things rock. available anywhere between fifty and a thousand kilowatts, these are bar none the single most efficient light sources around. they require starter circuitry, but the 20,000 hour bulb life, low bulb cost and unsurpassed energy efficiency will more than make up for it. i'd suggest S.C.W.A metal halide high intensity discharge systems, which are a certain type of pulse start hid.
Assailant's suggestion of waterblocking cold mirrors sounds really top notch. finding cold mirrors for a reasonable price is a major pain in the *** though.
try to use convection as best as you can, dont fight it. smart placement of vents can help direct heat to where you want it to go, or more percisely, away from where you dont want it to go.
i had a lot more to say about this, but i've had my head crammed in so many optics books i forgot most of it.
myren
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