| jjasniew |
The tiny cable toward the lower right corner is the problem, as the following proposal for a board arrangement illustrates.
This cable is 20 pins, spaced on the LCD at a solderable 0.05" pitch, however on the driver card they used the tiniest connector imaginable, with a spacing of probably 0.02. A long cable would have to be built to go from the driver board, as shown, all the way down to that small cable. Whether this would effect electrical signal timing is ??? There are some square labled pads similar to that shown in a previous reply - but not 20 of 'em...
The big cable at the top of the driver board is much more durable to folding, etc.
So I put it back together and it still works - using it now to type this in. Until I get a reasonable solution to the problem of that small cable, it'll probably stay together. BTW, color and response time are both excellent! |
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| Hellfire |
Scot_lad
(Or any one else for that matter)
If understand this right, the inkomming signal from for exampel a DVD player spans from 0 to 2 volt to indicate right brigtness for the lightbeem.
What happens if I make the volt go a little bitt higher?
Is the higher voltidge trapped by filters or is it missunderstod or can I trick the TV to produce a little brighter picture?
And is the tecniqe the same on a monitor?
Sorry about all questions but I´m trying to feed the university with some alternatives if they get stuck . . . .
By for now |
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| Scot_lad |
Hmm...I don't know. I think we should take the monitor and TV as seperate examples here...
It depends how the TV was connected to the DVD player. I'm in britain so it is possibly different from you. If you're using a coaxial RF cable then boosting this will do no good, as the TV converts that to a standard voltage - since this signal could have come from an aerial, the signal strength and thus voltage could be anything. If you're using that evil French invention SCART, which is most likely, then it'll be the composite video you're talking about. I think this would probably be dealt with differently between manufacturers, but in general I think there is too much circuitry between the input and the CRT to make it viable to simply boost this signal. What you could do though, is to find where the signal is amplified for going into the CRT inside the TV, and boost that.
As far as the CRT response goes to non-standard input voltages, they are usually linear up to about 110% of the standard point-point voltage. Although this varies obviously between manufacturers. I had an interesting web page about it but I can't unfortunately find it anymore. Basically, the more you overdrive the CRT, the less linear it becomes. You will have to investigate this on your particular tube as it will vary quite a lot, I would imagine.
As for an update on my progress, I've had no luck as yet with my solution to a curved screen. And I've not done much all week on it 'cos I've had no time.
It should be noted that you can get color 5" CRTs that are totally flat screen. Very nice. But they're not incredibly high resolution. Mind you I'm sure they're still good enough for my uses. My granny (yes granny) has one, but she'll not let me steal it. Most o fmy friends are scared to lend me anything to 'fix' because they know nothing comes back in one bit. And how true that is. That's the mark of a good engineer I think - willingness to experiment on ANYTHING.
Forgot to say, I would think monitors are quite fussy on input voltages. Increasing the input voltage of say RGB inputs may increase the brightness, but they will almost certainly saturate (not get any brighter) at the same brightness level on screen. This would have the effect of reducing detail and contrast. I wouldn't recommend this in case you wreck your monitor, but like I say everything's worth a try.
Cheers. |
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| xblocker |
What happens, if you increase signal levels to audio inputs? Yes, distortion! The same happens with too high video levels. May be, image whitens out or blackens out, depending on positive or inverse video modus. Maybe, the monitor's input circuit bring down the signal again.
You can't beat the physics here! The only way to increase brightness of a CRT is to increase anode high voltage, because this increases the speed of electrons, which hit the phosphor!!
What CRT-color-tubes concern, there's a limitation because of the pixel-mask behind the tubes frontglass, which can overheat and loose it's exact position !
xblocker |
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| Scot_lad |
Yeah, I think the only certain thing is that we don't know exactly what would happen, but it isn't going to be easy to overcome.
As an aside, I've mostly used TFT LCDs on laptops, but they're not particularly special. As for the LCD TVs that you can buy now, are they some kind of a joke? They're available in department stores right next to similarly sized (although FAR cheaper) traditional TVs, so you can compare the difference. So why would anyone want to pay 10x as much for an LCD TV, which has pathetic response times and blurry images. Perhaps they turn the colour up full in the shops so that they look more impressive. But they actually look garish.
As another aside, our cable company pipes TV to us at low quality I reckon. If you sit near the TV, the image is grainy because of the digital compression, perhaps they compress it a lot to save money or maybe the box we use to decompress it is just ****.
Dunno why I'm on a rant here, no doubt Frank 'xblocker' Sinatra will have a retort for me. |
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| Hellfire |
Thanks a lot Scot_lad and xblocker:) :) :)
That was much more information than I hoped for!
I´m beginning to get a slight grip on the whole concept of CRT now and hope to be able to give the university some new threads to spin on :)
I will post there answer as soon as I get it!
Thanks again!
Bye for now |
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| jjasniew |
Guess there's not much interest in the VP140 insides... After I resized all those !@*^%% pictures to be < 100K...bastards!
Anyway, for those of you who are actually interested in this particular panel monitor, but perhaps unwilling / unmotivated to say anything at all about it in response to my posts, I have the following FYI -
Joe,
Yes that would be great. I have 6 left and I am
waiting for a week or so before I put them on e-bay.
If anyone is interested then I will be happy to sell
them the monitor.
Thanks,
Lynnette
--- Joseph Jasniewski <joejas@ihpc.net> wrote:
> Lynette,
>
> The VP140 arrive today and it is operational.
> Thank-you.
>
> I belong to an on line club trying to turn flat
> panel monitors into projectors. If the VP140 works
> out, can I share Telamon as a source for these
> panels with the other members?
>
> Best Regards,
>
> Joe Jasniewski
>
> -----Original Message-----
> From: L Z [SMTP:telamon_it@yahoo.com]
You can get one for $150 US + ship with no VGA cable or power supply - without the hassle of getting outbid on ebay! That's a good enough price just to use as a monitor, IMHO. (I've seen a 1024X768 16.7M color 25-50 ms response Proxima OHP panel go for ~$350 the other day - with no VGA input cable. So "good luck" getting anything comparable at this price...)
The VGA cable it uses is a common item, P/S is +12V @ 2.5A, connector barrel negative. You can clearly see what you're up against by my photos, for the projector application -
I am not connected financially in any way. Just doin' a good deed for the day...Write Lynette at the above address or look up Telamon on the web for their phone number. |
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| frankbatzen |
Hi,
just wanted to praise Jjasniew for the pics because I know how impatiently I waited for response...
Since I am done I have no concrete interest in the monitor you use, but it's nice to see the insides of different types as well.
Maybe it will help you to know that the cable I used to elongate that 10-pin cable is about 15 cm long without messing up the timing of the signal. (I don't know if this is even feaseable, but then, what do I know?)
Concerning the blurry edges of my image (Blurry really is said too much, but it is not perfekt.): This is defenitely due to my lightsource not being a point-lightsource. I have experimented with a blind(? =blende in german. Basically a cover for the lamp with a hole in it to turn in into a point-light source.) The edges of the image are pretty dark with it installed, but the image is sharp. I will investigate the best suited shape and size of the hole. The picture will never be perfekt, but people who watched tv on the projector (and these people are not overly polite :) ) liked it.
Just to raise some ruckus: I think it's funny that a topic that basically evolved out of that 100"TV thing is returning there now with you CRT-guys;). I wish you luck with your approach, but I am pretty sure that it is even harder to do than with an LCD and is only suited for pretty advanced DIYers. I bet if it works you will have a much sharper but also much darker image. Sounds good too. Who am I talking to?
Frank Batzen |
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| frankbatzen |
I just remebered: Didn't somebody post a link a while back as a source for ffc with connectors? You could plug it into the mainboard-side connector and solder on the new connector, maybe even build a pcb for that new connector. Very reversible and harmless. I was surprised by that link then, since I wanted to go that route but wasn't able to locate anybody to sell a single one of these to me in Germany. I even offered to bribe one lady from such a company and she looked in the stock, but had none in the right size. These things are generally custom-made.
Frank Batzen |
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| Scot_lad |
Let me just add that I do not advocate the "Big Woody" at all, or any other 100" TV offering which uses a cheap fresnel and a behemoth TV. Not sure about the other CRT guys but what I'm developing is essentially a scaled down version of the commercial CRT based projector, using high quality optics, with no fresnels in site. I'm sure you remember my post several pages back explaining why I wasn't going for the LCD approach yet.
I'm actually going to start experimenting with high-brightness 5" CRTs from inside a real CRT projector, which will solve the brightness and colour issues, and also the flat screen problems. Only thing is they scare the hell out of me because they're big buggers and could give me one hell of a shock. But once again they were free so I can't complain. That will be next week's project. And I'll still offer advice on the route using cheap normal TVs as before.
As an extension to that - if you are using nice single-colour CRTs, where you don't care about the aperture grid or whatever, because they don't have one, you can build your own relatively cheap control circuitry for the CRT beam, which would offer increased resolution over the old electronics which controlled it before. (presuming you stole the tubes out of an old projector)
So yes, whoever posted before, I am going for the knee-deep DIY approach, which involves lots of complicated electronics. But it's fun and the results will be great. I just hope we're not all dead and buried before I get round to finding some results. I'm getting a nice new digital camera all my own next week so watch this space for lots of pics. |
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| wnichol |
Hello,
It has been a while since I have last posted. I have been very busy with school but have kept up reading all the posts. Anyway, After searching for a light source the only thing that I could find was the 500W halogen worklight. Searched everywhere for at least an LOA but no luck until I took a trip to my local hunting and camping store. I found my holy grail! It is a 100W halogen handheld spotlight.($40) that produces 2,000,000 candlepower!!! Since this is similar to a flash light most of my light was directed directly at my LCD. I DO NOT have blurry edges!! They are nice and clear. This blows the worklight away and runs a lot cooler, brighter, and whiter.I have not been able to do very many tests with it because I am very busy.
There is one downside to this light. It is run off a rechargeable battery and unfortionately the battery only lasts for 20 min. and you can't run it off the plug that was supplied with it because that is just to SLOWLY charge it. Would I be able run it off an AC/DC converter if I disconnected it from the battery?
Im sorry but I donot have pics yet. When I get them would someone be able post them?
I have to get going. Running late for class.
Chris |
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| Axeman |
HI guys..
It's been a while since I last posted here, mostly because I haven't done much with this project lately. I'm finding the CRT discussion on here extremely interesting. If I could find 3 small flat B&W CRTs then it shouldn't be too hard to rig up.
Does anyone have the projector.zip file Myren posted? I noticed that the directory that it's supposed to be in that contained pics of his OHP etc is accessable, but there is no projector.zip file. Myren, if you're reading, I'm ready to buy a VG150- But I would _really_ appreciate seeing it's deconstruction first. Thank you.
Another really interesting thread is the laser projector thread. This approach offers the best of both worlds(CRT and LCD). Multiple scanning rates, and extreme brightness. Plus the added bonus of low power consumption, and long life. There are lasers out there that can produce the entire visible light spectrum(or close to it). This would be the way to go rather than red, green and blue lasers(green and blue being very expensive). Anyway, food for thought. |
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| gav |
| Just something i've been throwing around in my head, I work for an audi dealer and i'm pretty sure our warranty section has just recieved a damaged xenon gas headlight assembly - but the lighting side of it OK. Considering the blinding nature of these devices, it might be perfect for my first LCD attempt (as long as my ebay bid holds up!!)..any thoughts on these globes? it includes the controller so all I have to do is hook up 12v to the controller and close my eyes :) |
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| Timtimes |
Should work as long as you get a twelve volt power supply with appropriate amperage.
There is one downside to this light. It is run off a rechargeable battery and unfortionately the battery only lasts for 20 min. and you can't run it off the plug that was supplied with it because that is just to SLOWLY charge it. Would I be able run it off an AC/DC converter if I disconnected it from the battery? |
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| Grumpy_Git |
jjasniew
Thanks for the pictures of your LCDs guts, I'd love to have one of these monitors, especially at that price, The cheapest LCDs are around £300. Too much for a poor student like myself.
Anyway, thaks for the pictures, at least I've an idea of what I'll be doing once I find myself a display.
Nick.:mad: |
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| frankbatzen |
I thought about using xenon car headlights for my assembly, but canceled it because they all are just 70W. I don't know if the xenon lights are more efficient than my HQI bulb, but mine has 400W, which is enough, but not extremely bright (not using a proper reflector...). I would love to know if the xenons work, since they are a LOT closer to a point-like lightsource than mine.
I still think they might work well with a white screen. I don't want to talk you into it, but I think you should try it.
BTW, I was asked to post screenshots of the image my setup produces, but with the camera I had that was
impossible. With those pictures you would get a totally wrong idea.
Frankbatzen |
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| Hellfire |
Timtimes
Basic electronics says that a lightbulb only lets a fixed amount of current through at a fixed voltidge. Therefor, if You provide the right voltidge coresponding to that from the battery, You should be fine.
But look out for any other electronics inside the flashlight and if any, do NOT bypass them. Hock the converter to the battery conector. There might be some kind of regulator that holds the current down but I do not think so.
BUT DO NOT TAKE MY WORD FOR IT! GET A SECOND OPINION!
Bye for now |
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| SuperDave |
A few days ago I was asking about candlepower compared to lumens...This was because I had been thinking of getting one of those 2,000,000 candle (hand held) spotlights as well. I know they are extremly bright, the light is already reflected, and the run quite cool. I never even thought aboiut the fact that most are battery powered.
I was also considering those xeon headlights as well...but when looking for my answer about candle power I found a message forum geared towards flashlights and found that car lights really aren't that terribly powerful as opposed to other light sources...they are just focussed...but I had been meaning to ask others here because I still think they are damn bright and could do the job. My biggest concern would be their blue tint.
Good luck with these two ideas I would love to know if they work well. I just ordered an Elmo projector and I am figuring out what LCD monitor to take apart...I will eventually move away from the Elmo but want to get something going quick to get me all giggly and motivated.
Later,
Dave |
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| SuperDave |
jjasniew, in response to your photos, I loved them...Thats exactly the kind of things I like to see and I plan on trying to do the same with my project.
Since you seem to want to talk about it I have some questions...
It seems to me that you end up with a completely unobstructed view through the LCD with the circuiboards where they are in your last picture...I know the cable doesnt allow you to move the board much but cant you get around this fairly easily by just mouting it perpindicular to the LCD? Or am I completely missing the point???
I dont remember who it was that was using the VG150 project...but does it look quite similar to this??? I never got to get those pictures.
I had been looking for a 15 (preferably smaller) monitor with a higher contrast ratio than 350 but cant seem to find any undre $500 so I had anticipated going with the VG150...but for $150 (MY GOD IS HE CRAZY) I may have to go with the VP140 and screw the CR and Response time for now.
Please Please Please tell me if I am right that there is an unobstructed view throught the display but the PCB relocation is quite limitted.
Thanks,
Dave |
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| jjasniew |
I'm glad I stirred things up!
I looked up the cabling suggestion from Germany and it looks like it'd solve the problem. However, I see no option for sales in the US, so it may not be viable from over here. Probably should check it out.
I would not assume that Telamon cant ship overseas - I'd check it out via e-mail to Lynette.
Yes, for the vp140 an unobstructed shot through the LCD is possible - provided you can solve the PCB relocation cabling problem.
This of course implies that you can simultaneously solve the mounting and cooling problem for both PCBs, so that along with the panel, it all fits atop the OHP.
There's a lady here at work who does precision soldering. she said she'd help me extend the cable. I'll likely give it a try next week and will report the results here -
I'm seriously considering bidding on a 9" CRT Barco on ebay. Here's a picture of the insides, for all those going the 3X CRT route, as an example of such an arrangement -
I think the 50X brightness over normal you'll need to see anything on a big screen show may not be possible, w/o some real special tubes. The tubes in the Barco shown are liquid cooled, because there's so much energy hitting the phosphors to get the required brightness. (Take a straight-on look through the LCD panel atop a 7K lumen OHP, to see how bright that really is...) |
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| jjasniew |
| 3X CRT concept shot - |
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| fender4 |
Thanks for getting things going again, Joe! It's good to see some new names/fresh ideas here, too. It looks like I am going to be looking or a new light source just as some others are, because I think the LOA (non-point-source) light is causing problems with my image.
I received my nView Viewframe Spectra C from Inventory Solutions yesterday, and I have spent about an hour playing with different configurations---all of which have resulted in blurry edges. I was using the LOA 65w Fluorex light------>the LCD panel------->lens.
The three lenses I have played with are an Office Depot page magnifier fresnel, the Fujinon Projection lens from Surplus Shed, and a 10cm diameter double convex lens, also from Surplus Shed (it has a focal length of 20cm). I also tried the fresnel before the LCD with the DCX lens after to mimic an OHP setup. I always got blurry edges, and the DCX isn't large enough to project the entire image anyway.
Does anyone know if the projection lens on an OHP is a double convex lens or an achromat lens? I will probably just decide to dismantle an OHP and use the parts if I can't find a combination that works. I would post images, but they are honestly not watchable at this point.
BTW, the LCD panel I have is a 640x480 unit with s-video, composite, and VGA inputs. It seems to be a nice unit, and I am fine with the resolution. I have taken it apart (of course!) and the panel itself is easily movable for positioning options. The fans are noisy, though, so I might look for a nice computer fan.
Sorry to ramble. Good luck everyone.
-f4 |
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| Marklar |
| Well this is my first post here I found this site this morning and I got to page 20 and said ok im not reading the rest right now my eyes are tired. I have been wanting to build a projector for some time now and i did make one out of a 19" TV about 2 months ago but it was to dim and I have been trying to figure out how to make it work. As for a light source I dont know if anyone has said this but I was at home depot today and saw a florecent dusk to dawn light that puts out 7000 lumens and I figure with a reflector that would be more than enough light but I didnt buy it yet because I was wandering is there a such thing as to much light? They also has a smaller flood like that was 2500 lumens both lights were very inexpensive the 7000 lumen one was $35 and the small one was $25 and they dont get near as hot as a halogen and last many years the bulbs only cost around $13 they do have a small electronic ballast that does produce little heat. I have found a great surplus site that has many lenses and LCD screens Im waiting for a reply from one of the sales man to see if he has some good LCDs. I have found Delta 77 lenses on that site for $12.50 these are the same lenses used on high quality big screen projection TVs. I will hopefully start my project soon and keep yall posted with lots of pics. Please let me know if there is a such thing as to much light. |
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| Marklar |
| Oh yea Im in the construction and you can get windows that are called Low-E that reflect heat they work quiet well I saw a test setup at home depot where they had a 150W flood behind normal glass and one behind the Low-E glass and I could tell the difference, and this glass isnt very expensive at all. |
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| fender4 |
Marklar,
Welcome to the board. This thread IS very long, but it worth taking the time to read it...lots to be learned from others' successes and failures.
The fluorescent light you mentioned is probably similar to the light I mentioned in the post before yours. Mine is made by Lights of America (LOA) and it does produce a good bit of light. The only problem is that it is not a "point-source" light, meaning that the light is produced throughout the length of the bulb as opposed to a metal halide bulb that has its source of light in a very concentrated area. The LOA seems to wash out the image because of rays from different angles (from different "sources") striking the LCD. This is minimized with a point-source light.
Thanks for the tip on the low-e glass. It sounds like it reflects the IR spectrum.
-f4 |
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| xblocker |
Joe, regarding the lenses of OHPs, i have 2 OHPs, one of them has 3-lens system, the other 2 lenses. Most objectives have more than 1 lens to compensate the image distortion of only a single lens. The more convex a single lens, the shorter the focal length and the more distortion.
I'm too searching for another lens-system, the best would be zoom-objective between 290- 320mm, cause my projector is standing in the middle of my room now, making 110" image size. But it's hard to find this!
I would recommand the guys, who go the LCD-route:
Bid on OHPs and Projection-panels ! OHPs over 5000 lumens will make nice images. Then you will have no probs with melted fresnels, cooling, lightsources, optics, broken ribbons, pcbs....!
This can be cheaper and less annoying.
I've paid about 400 EUR for both.
And if you say, but it's fun, you'll have enough work to built a DIY-screen!!
That's what i'm doing actually !
Cheers
xblocker |
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| jjasniew |
I think the metal halide "fish tank" light is the best choice for those doing DIY light source for a LCD panel.
Otherwise, as previously suggested, get to know your OHPs and get a good quality one, >4K lumens. There's a HP-A305 (7K lumen, MH) on ebay now for $150, from our friends at Inventory Solutions...
From what I've read on the web, lens quality goes up with projector "quality" - which usually means lumens output. So even if you're going to DIY the light source, get the lens from a good quality, albeit dead OHP.
Watching the VP140 with a DVD movie, well the Nview Z350 isnt even close, on neither color rendition nor response. So you can get projection panels, but I suspect that the technology "generation" of the LCDs in these isnt up to what's pretty ordinary in the last few years in monitors.
That's why I have smug thoughts in passing on that $350 Proxima panel. It may have the same color capability, but I bet it doesnt respond as fast as the VP140. At a 10" diagonal, it would let about 1/2 the light through of a 14" diagonal unit.
My hopes are;
1. that I can solve the cable problem and it still works.
2. that I can get the brightness/contrast adjusted for a decent looking image.
3. That I can package the PCBs and LCD so they dont get destroyed before I get a chance to enjoy the unit.
Later! |
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| gav |
CRAP! they have to send the xenon light back to Sydney for the warranty guys to investigate it...i wonder if I can "make" another one defectable :)
just a quick question...everyone who has got to the stage of a viewable picture, what size screen are you projecting? since i really only have room for about 80 inches, i suppose i don't really HAVE to get the highest (most expensive) resolution lcd screen, right?? (i'm after a ovation 820) |
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| andrewjames1000 |
Gav
I have a proxima ovation 810 panel which works really well at about 60inches screen. I haven't really tried bigger. The panel is great with DVDs. In my experience on a DIY system 640x480 is fine for whatever you are displaying. I hope to post some pictures within a couple of weeks.
To everyone else looking for a light source I mentioned this a long time ago. Try a EVD OHP halogen bulb. You should be able to get one for sub £10/$10. They produce a very bright light up to 5000 lumens. I'm not an electronics expert but I think a standard power supply should power one. These should be more pointlike compared to the other stuff people are trying (except MH). One decent fan should be enough to cool one of these.
Good Luck
Andy
p.s. not an april fools joke this time (-: |
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| Marklar |
Zark,
What model # is that lens you are useing I cant seem to find one? |
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| cowanrg |
I've read this thread page by page last weekend, and it has helped me quite a bit. but, since i have read it, i know how many ppl say this exact thing, so ill get to the point...
right now im using an nView Spectra C with an overhead from office depot (they have a nice return policy, and i wanted to test a 3000 lumen before i bought one for sure). it works REALLY well, but i would like higher resolution. i noticed ppl talking about the viewsonic VP140, but i can only find it for over $400. this seems pretty high. is there another viable solution for cheaper? i could get a high res projection panel off ebay for much much cheaper.
plus, for all you ppl messing with color settings and such, get powerstrip. it gives you full control over all color, brightness, etc... settings. since it controls your video card directly, it even affects overlays. (dvd, anything that uses a hardware accelorator, games, etc...). great tool, plus you can set it up for hotkeys to quickly switch from different resolution/color settings, with one click. its free too.
also, im going to rig this current overhead projector with an LOA. i figured, why not BUY an expensive OHP, when i can just modify a current one to be bright. most OHP's have enough room to play around, and you could put 2 of these in there if you were creative. i just dont like the heat that the OHP produces, and the noise would be a nice thing to remove, even though with a movie on, you dont notice. |
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| Marklar |
Well I have decided to go the easy way. Why try to reinvent the wheel when you can go buy one real cheap? So far I have found 65 watt 7000 lumen florolux lights at home depot you can either buy the lamps and ballest seprate or you can just buy the whole light if your not sure what kind of ballest to get. The whole light can be bought for $35 each at home depot heres a link direct to the fixture Home Depot . I am going to go with a proven design and used a standard overhead projector these can be bought off of ebay for under $50 for a real nice unit. It doesn't matter what kind of light output it has because it will all be removed just make sure all the lenses are clean and not all scratched up. The other major part is the display many people I see are using regular LCD displays well I don't mean to sound like an *** or anything but most LCDs are not made for this so why use them? Thats why Im going with the regular LCD display made to work with an overhead projector. I just got 2 for $80 on E-bay with s-video, composite, and vga inputs with a 640X480 resolution and it even has a nifty remote to adjust all the levels. So here we are $200 later, open the OHP and rip the guts out of it, fan and all, the new lights burn cool and electronic ballasts don't put off hardly any heatso theres no reason for a loud fan. Just look at the drawings I made its real easy to follow. that last thing that I was trying to figure out was "DAMN IT that thing shines so much light out the top it lights the whole room well get a thick cloth and glue it to the bottom of the head makeing sure the head can still easly be adjusted and its not blocking the lenses, WOW problem solved. I have seen the regular projectors and LCDs in action when i was in school but the bulb life sucked, it made alot of noise, and it lit the room up. Well hopefully this will fix those problems. I hope to have a fully working proto type in a week or so and i will get lots of pix my digi cam, it owns you. :P
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| Undream |
would something like this work? I sketched it up. I read the first ~30 pages or so of this thread, and could hardly bear the fact that people were slowly giving up with the LED's. I really think if you could condense as much of that light as possible, using something more than just 45 degree mirrors, it just might be possible. Then, I thought about telescopes -- and how they use Parabolic mirrors to amplify faint light, and I just had to do this sketch. If I am completely stupid, then, let me know. I've just been really excited about it since I found this thread. I'm very impressed with what is going on here. Even if this design needed 100, or 150 LEDs, it would still be more cost-effective, quieter, cooler, and just plain ingenius over using standard halogens.
I'd love to hear comments.
Parabolic mirrors can get expensive as you go up in size. I've seen a 4.5" for $36, a 6" for $49, and an 8" for about 90. 10" + are usually used for high-end telescopes, and they are usually only produced with extremely high quality, and hence, are super expensive (hundreds) |
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| Marklar |
| Thats an awsome idea to focus all the LEDs to a small point!! |
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| Undream |
Well, when I said $50 for a 6" parabolic mirror, I must have been on crack. I did find a 4.5" one for $36, but it was an f8, which means the focal length is 4.5*8 = 36 inches. thats just too far for a normal projector enclosure. especially when you only have 4.5" diameter of LED circuit board to work with. A 6" f4 would probably be the smallest focal length parabolic telescope mirror that you could actually use -- and they start at about $99, and you might be able to E-bay one for about $80. Even then, you need 24" between the mirror and the lens positioned at the focal point -- and of course, the LEDs would have to be slightly further than that, as to not interfere with the focal point collection of light. Ideally, I would use a 8" with about a f2.5 focal length (20 inches). Good luck finding one of those. Even if you did, it would probably be near $200.
Plan B.
I'm not too sure if they would be good enough, but I found a 12" parabolic aluminum reflecting surface Here
If that would work, not only would it be CHEAP, but you would have tons of room to work with the LED's. And the beauty of it is, it doesn't matter where you put those LEDs directly across from the reflective surface, because the light will be reflected back to that focal point. I would really like to see what they are capable of. For $29.95, that would be an awesome solution. |
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| Undream |
| the focal length on that 12" diameter aluminum reflector is only 3". That would make things very tight within the casing! |
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| Hellfire |
undream
I was interested in building a high power telescop a long time ago and found in a book how to make a high precision parabolic mirror. This was not expensive as far as I can remember.
I think You use a thick glass from a boat (from the port hole) and polich it to the right specs. Then You coat it whith silver oxide I think.
This maybe sounds complicated but I do not think so becouse it was intended for beginners.
This way You can do a parabolic mirror any size You want!
Bye for now |
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| Gunawan W |
fender4,
I did some experiment using Delta 20 Proj. lens (part # L1813) and Plano convex lens (part # L1593) from www.surplusshed.com:
In my setup I use Delta 20 (I took the lens only, it has f=90mm, dia:3") for reducing the image from LCD panel (15") to the size = 5". From that I use second lens (Plano convex lens with f=31,8mm, dia:11,4mm) to projected image to the screen (70" image size) with projector distance =16 ft. If I want smaller or bigger
image size, I just move Delta 20 forward or backward, also if I change projector distance, just move Plano convex lens to refocus.
I think (in theory) using 2 type of convex lens, short focal length for reducing LCD image and long focal length for projecting the image, will solve our problem with big LCD panel (14" up).
Hopely it will work. |
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| Grumpy_Git |
UnDream.
Have you considered using front surface mirrors to fold the focal length of the parabolics around a fixed space. This could be a solution and keep the Size of the mirror and the focal length down.
Nick. |
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| Undream |
Hellfire,
Thats a fantastic Idea. I've been researching it as much as I could the past few hours. What I found is..porthole glass is really hard to find. if you could find it, you'd be lucky to find a slab of it that was 1" thick -- and after a ton of time and effort grinding and smoothing it down, the curve just wouldn't be deep enough to get an acceptable focal length. you'd end up with a 12-16" diameter with a curvature of f5 or above -- which means 60" or more focal length. I don't want my projector to be more than five feet long :\
So, unfortunately, I think thats out of the picture, along with expensive telescope parabolic mirrors.
I'm really wondering if there is some way...that you could take one of those aluminum parabolic reflectors, and coat the inside of it with something better than plain polished aluminum. Does anyone have any ideas about that? |
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| cowanrg |
well, i used an LOA inside a standard OHP like i said, and no such luck... these babies have a TON of light, but its just not focused enough. i was kinda hoping enough would just get through to work, but it didnt. im going to experiment some more, and see if i can find a way to focus this light, and possibly attach it to the bottom of the projector.
if there was a way to focus and concentrate the light that comes out of this thing, i definately think it would work. anyone have any ideas? |
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| Undream |
Well, after giving this much effort, I have come up nearly empty handed. I started broadening my search to include spherical mirrors and other convex mirrors. The result of a spherical mirror will be slightly less accurate and precise as a parabolic mirror, but, since the optical lens collecting the light is going to have a few inches diameter, a precise focal point reflection probably wouldn't be needed.
So, my best bet would be this:
40cm Convex Mirror
MIRROR - SPHERICL 40CM/CONCAVE
Catalog Number(s): WL3525A
Description: EAGLE CONVEX GLASS CO SE, WL3525A.
made by Eagle glass Co.
Thats about 15 3/4" diameter -- plenty big enough
it doesnt give the distance of the focal point, but, you would easily be able to find it by getting out a flaslight, pointing it at it, and taking a piece of paper and moving it back and forth until you see when the light is converged the closest. Designing the LED panel using a spherical convex mirror means that packing as many LED's across from the mirror as close to the Center of the mirror as possible would yield the best results, and as you added LEDs further and further out on the diameter of the mirror, they would be less accurate and stray slightly from the focal point. If I positioned the capturing lens slightly inside of the focal point, I don't think this would be a major problem. we would still be getting well over 95% of the light that is being reflected from the mirror.
If Vince is still around here, I'd like to know if he thinks these LEDs are bright enough. Its just a lot of money to throw around (well, maybe not a lot if I didnt have a family to support). Wish I could borrow the stuff to test it out before I made any purchases :)
I'll post some more sketches soon. |
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| Hellfire |
Undream and everyone else
Do not forget that a parabolic mirror can olso be used with other lightsources like LOA and others.
Underbeam, You hit the neil with this one :-)
But I think that You realy need a point source as small as posible and from that spred the light out in a correct manner to get a sharp picture . . . . . . . or do You?
Bye for now |
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| fender4 |
Thanks for your input! I think I understand what you are doing...are you basically using two plano-convex lenses: one with short focal length for "reducing" the LCD image and then one with a long focal length for projection? That would make sense, I think. I have tried using a double convex lens, with the same focal length for both sides, but I am getting a very blurry projected image, espcially around the edges. I have heard that an achromat lens can correct for distortion around the edges. Would this correction be necessary when using two plano-convex lenses of different focal length? I'm probably asking too much...maybe I'll just try it out. Thanks again for the tip.
Question about the parabolic reflector: Once the light has been condensed to a point, it must diverge again enough to illuminate the LCD. Wouldn't the light be scattered again, defeating the purpose of condensing the light to a point? In other words, wouldn't this be the same thing as passing a light through a lens? I'm not trying to kill the idea, because I think it sounds great. But I'm just trying to see the real benefit of doing this.
Good luck everyone!
-f4 |
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| xblocker |
cowanrg, this LOA is nothing else than a very bright backlight ! Its unpossible to focus it properly through the LCD to projection lens. I think you have even better results without the fresnel. Large sized light sources are never a good choice for projection, because they are hard to handle from optical point of view.
If you look at MH lamps or halogen types, ALL the power is produced within a small area of a few sq mm! This is where parabolic mirrors and fresnels make sense. A LOA is a huge light source and diffuser too. Every point on the bulbs surface is a little, but not so bright lightsource, which is emitting light into all directions.
The same with these LED arrays.
xblocker |
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| Scot_lad |
Underdream: Ages ago we decided that LEDs are too expensive and don't give out a lot of light. In fact, LEDs actually give out LESS light per £ or even per square inch than other sources, such as fluorescent lights.
I've been reading about this point light source thing with little interest (I'm not doing LCD as everyone knows) for quite a while. I think there could still be some confusion with it, so here is my understanding of it for you to correct if I'm wrong...
If you're using a fresnel, as in an OHP, then you want a point light source. This is because the fresnel takes the point light source and turns it into a nice parallel beam of light. If you don't use a point light source with a fresnel, then all of the light that isn't being produced at the focus of the fresnel, is going to be bounced around in all kinds of directions, which isn't going to be efficient and certainly won't produce a good quality result.
Fresnel -> Point light source
Not-Fresnel -> Bigger light source, although polarisers would apparently be good so that the light travels through the LCD in parallel. Nobody seems to know much about polarisers.
Yes you need fresnels in an OHP, because the light goes from a point source to a parallel beam and then back to a converging beam, through a big LCD panel, and into some nice quality optics at the end of a big arm, before being focused onto the wall.
Also, I've seen something in a lot of people's diagrams over the many pages of this forum. You do realise that if you're going to have a lens to project the image, you can't have the image source greater than the size of the lens, because that would require something we haven't harnessed yet: Magic. |
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| fender4 |
Good points, Scot_lad...we need you back on the LCD side! I wish you the best with the CRT project. It is very interesting.
One question, though. If the projection lens must be larger than the source, then how do OHP's get away with using a lens that is probably 4X smaller than the source? Is this the work of the fresnel before the LCD or a convex lens in the "head"?
-f4 |
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| xblocker |
To avoid confusion about all this lenses: In reality we have two (!) image systems! One is the light source projected right into the projection lens's plane. This is the lighting path. The other is the image path going from LCD through projection lens to the screen.
The size of projection lens doesn't depend of the size of the LCD panel. It only depends of the speed (american term?) and focal length of the lens.
If the light source isn't so bright (CRT), the speed must be better, that's why CRT lenses have to be larger. Similar conditions as in photography.
In the case of an OHP this isn't so important, because the LCD's image is concentrated through the illumination path. Important is only, that focus lenght > object (LCD diagonal)!
Hard to explain...
xblocker |
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| Undream |
| This is exactly what I was looking for, was someone to tell me it wont work, because, I think I was getting ahead of myself. I need to read up on many more things. I really didn't know what I was talking about beyond the light source, thats what I was really concerned about. I figured I would figure out the rest later. I liked the idea of LEDs, and was trying to think of a way to take many, many of them and converging the light to one point. I would gladly spend $150 on them as a light source, over a $40 halogen or something. I didnt want to have to deal with heat, fans, cold mirrors, and replacing bulbs. I thought over time, they would be much much less expensive If you have to replace another light source 5, 6 or 7 times to match the life of a LED? |
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| wnichol |
Two quick questions.
What direction should the fresnel be when its before the lcd?
What projection lense would anyone recomend for my final projection lense (I'm using a 4" lcd)? |
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| fender4 |
Hey, I just found out a way to search this thread (since the search on DIYaudio doesn't do much good for searching within a thread). At the bottom of the page, there is a "Show Printable Version" link that will take you to a page with all of the posts show at once! Then you can use the Ctrl-F or Find function to search for keywords, topics, parts, etc. Maybe everybody already knew that, but I sure didn't. It would have save me a good bit of time seraching for things. Hope this helps.
wnichols,
For you purpose, I would recommend the Fujinon lens from Surplus Shed. According to the description, it will accomodate a source up to 4.25", so you may be in business. I have one, and it does seem to be a hih quality item. Good luck with it.
-f4 |
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| contrapasta |
It may be just me, but I'm not understanding jjasniew's problem with the vg140, with the last picture it shows the panel with the circuit boards completly out of the way of everything... Am I missing something... Which connecter is the problem?
So anyways, jjiasniew (or anyone) have you solved the problem, is the vg140 board workable for our needs? |
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| contrapasta |
| And is this the connecter your referring to that should go here?? Did you try to email them to see if they would sell overseas?? |
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| gav |
| ever since i began reading this board and looking at the ovation lcd monitors on ebay, the prices seem to be going up and up...are we all bidding against each other??? what seems to be a reasonable price to pay for a 820? |
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| Scot_lad |
Just to mop up a wee question: OHPs have a much smaller lens than the size of the image source, because the light beams converge towards the smaller lens. This is achieved because of the fresnel arrangement between the light source and the LCD panel.
As for image 'speed', sorry I've not idea at all what that means, XBlocker, maybe you could explain for the non-US guys?
I am looking forward to watching my latest DVD on some kind of projection system: does anyone remember Jamie and the Magic Torch?
www.80snostalgia.com will provide a nice distraction from projector panels and lenses... :) |
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| Grumpy_Git |
Scot_lad
I asume that by speed, Xblocker is refering to the aperture of the lens, allowing more light through and thus (for a camera system) allowing a shorter or faster exposure.
As For Jamie and the magic torch, I never really liked it, Will 'o' the wisp was more fun.
Nick.
I've no money at the moment, grrrrrr. Experimenting over... |
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| lokost |
fender4
Try reversing the Fujinon lens. Normally you have to place the object very close to it to project a good image; I have observed that by reversing the lens you can increase the object distance and therefore easily cover a much bigger object. The wide angle attribute of the lens is still preserved. |
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| fender4 |
Thanks or the tip, lokost. I've tried it, and unfortunately, I am still missing about 30% of the image. I have ordered a plano-convex lens that has a focal length of ~12" (the same one that Gunawan recommended), so hopefully I can use that to "gather" the image and send it to the Fujinon. I think I am being limited by the short focal length of the Fujinon.
-f4 |
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| jjasniew |
You have outlined the problem precisely. I have not yet checked them out, to see if they'd mail overseas.
In your second photo, the connector is just underneath the edge of the PCB where your arrow points. I believe their solution will work; it's just a matter of getting it. |
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| jjasniew |
| I noticed a motor and color wheel for sale at www.bgmicro.com for $1.49 - #ACS1060. Dont know if this could be made useful for anything, but for the price, thought I'd mention it. |
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| jjasniew |
The idea of "We" may extend far beyond the active readership of this forum and certainly beyond the active participation.
I think the market for panels on ebay is hot! People are buying OHPs and panels all over the place! I believe most folks "get it" that you can put these two pieces together, get decent projection performance of a video or PC screen, for far less than the cost of a real projector.
From my personal experience, I'd get a panel from any other possible source, rather than 'ebay'. I'd also advize to know what you're buying, or for all your trouble, you'll end up dissappointed.
Particularly in the area of color, response time, transmission, screen-door.
Color means yeah it's color, but they're all not quite right in terms of hue or saturation.
Response time means that when images move fast, the panel can keep up with it and not get all blurred.
Transmission means that for all the light you pump through the thing that you'll get enough out to be useful; better than the necessary "pitch black room".
Screen-door means the granularity of the LCD. Does it look like an image with a piece of chicken wire fence in front of it and to what degree?
Maybe it's time to start a panel/LCD quality thread, where we can put our experience with various panels.
I hope all the VP140s are sold by now; great deal considering what you have to go through and what you end up with otherwise. IMHO, of course! |
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| xblocker |
Scot_lad, of course 'speed' was the wrong term. What i mean is 'focal ratio': focal length / aperture, normally specified as a F/xxx value
xblocker. |
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| Marklar |
| Well I was at the electrical supply house today so I asked a friend there for some help with lamps so he gave me the GE Lighting book!! This can also be found at www.gelighting.com but it is slow as hell and will take you 1434412435 hours to find what you want. I have been looking through the book and I have found some focused 3 degree lamps with 10,000 lumens and rated for 3000-6000 hours and there do get hot so a fan would be a good thing to have but the thing is the color temp on them are from 3000-4000 k is that good for projection? if not can some kind of filter be used to fix that problem? If you want to you can call GE tech Support to 1-800-GE-LAMPS Ill be giving them a call and check some things out. |
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| Marklar |
http://micro.magnet.fsu.edu/primer/...emperature.html http://micro.magnet.fsu.edu/primer/.../colortemp.html
I just ran across these and I had to share. I also found something real nifty!!!
Color Temperature Conversion Calculator
Use our color temperature conversion calculator to determine the appropriate filters for converting microscope illumination from one color temperature to another. Simply choose the starting color temperature and the desired final color temperature from the pull-down menus, and our interactive Java calculator will automatically perform the calculation |
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| Marklar |
Well heres the specs of the lamps I found tell me what you think.(The ones in the yellow)
And here is what it looks like.
I will soon post the price of the lamp and ballast soon as I find out. |
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| cowanrg |
[QUOTE]Originally posted by Marklar
[B]Well heres the specs of the lamps I found tell me what you think.(The ones in the yellow)
quote me if im wrong here, but, uh, look at the color of that lamp... its hella yellow. 3000K has a lot of color in it. it might give an unwatned hue to the image. |
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| fender4 |
I think this bulb is nice because of the built-in reflector, but the color temp is not that good, and 11500 lumens from a 150watt bulb isn't really that great either. I've seen around 100 lumens per watt with some MH bulbs, and also with a much nicer (near 6500k) color temp. But that doesn't mean that aren't somewhat suitable. Let us know if you find a price.
Does anyone have any experience with the metal halide bulbs at Home Depot? I think they have 175watt and a 400watt, both made by Phillips, but they don't have any specs on the packaging. They are around $20.
Thanks for the links, Marklar. Let us know if you find any pricing info on those bulbs.
-f4 |
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| Marklar |
http://micro.magnet.fsu.edu/primer/...emperature.html
Goto that site about halfway down the page it will show you Color trmp dosent matter. What did I say it dont matter?? YEP!! Kodak makes corectional lenses and on this site there is a calculator that will show you what lenses you need.
To Obtain: 5500K Starting From: 3000
Add these filters to the light path 80A + 82A
Dont forget to read every thing I post its very important stuff fellas! |
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| Marklar |
| well they do make a 1000 watt bulb with 6 degree beam thats 63000 lumens but I thought that was over kill it color temp is 4000 and is good for 3500 hours. |
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| Grumpy_Git |
Marklar
It's all very well having these temperature correction filters but they are likely to heavily cut the overall output for the bulbs and it makes just as much sense to cut out another problem and get the best possible solution (high colour temp lamp) rather than adding extras to the project, I for one will continure looking for a white light.
Nick. |
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| lokost |
filtering
A real kicker would be if one could adjust the image colors to simulate the filter output before projection with the low Kelvin lamps. |
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| Grumpy_Git |
lokost
Surely thats what the Gamma correction in programs like Power strip are for?
Nick. |
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| lokost |
Grumpy-Git
Thanks for the pointer. I can now see "101 Monitor Profiles" on CD for $9.99 on ebay.:D |
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| Marklar |
| Well from what I have seen to save you time if you dont want to use that bulb then don't look for a bulb from GE that was the best one i could find all the others that are focused point bulbs either have 3000 lumens with 2000+ hours life or 20000+ lumens with only 100 hours or less life this is the only route with GE if you want life and lumens on a point source light. |
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| Gunawan W |
fender4,
sorry didn't mention to you in my previous post that I just did the first half of the experiment, I only did the "reducing image step". I don't know the next step result, that is "projecting the image to the screen step", because I still search the best light source I can get.
BTW from theory, if we put object (LCD panel in this case) greater than 2x focal length (fl) of convex lens, we will get image size smaller than the original.
http://www.education.eth.net/acads/physics/light-XI.htm
Shorter fl will reduce distance from LCD panel to the lens, but will produce distorted image (ie:blur image on all corner of the image).
In my experiment, I used fl=90mm (3,6") it was blur!
But, when I move the lens further away from 2xfl, the whole image became clear. It was 3" image, with distance from LCD to the lens is around 16".
you're right about "printable version" now it's a lot easier to find something in this looooooooong thread! |
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| jjasniew |
I started a thread is for voicing your experience with various LCD panels, regarding suitability for DIY video projector use.
This includes all forms of LCD devices; raw panels, projection panels, panel monitors, panels from actual projector units, etc.
Hopefully this will be of use to those seeking a panel to buy, but asking the question "which one?" This way, they wont have to read/search through the whole giant thread for clues...
Please take a moment to enter any useful information there, if you've bought an LCD panel for this project, or have any other experience with LCD based projection devices.
Someone else can start a similar thread for the CRT sources! |
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| Axel666 |
Hi there, i found this thread a few dayz ago and I'm bizzy reading it, got to page 31 from the 85 so I'm catching up. First of all i want to compliment everyone on the great progress being made =) i can't wait to start making my own projector. But i have some other stuff i have to finish first. Anyway the reason I'm posting is that i saw a lot of people where having trouble finding high res lcd modules, i happend to stumble across some intresting pages selling modules that are about 6 to 7 inches and have a resolution of 640*480/ 10 inch with 800*600. They allso have the 16:9 with 1440 to 234 res.. erhm look for yerself me summing this up makes no sence :D
http://apollodisplays.com/
intresting pages from lcd manufacturers here:
http://www.mark-products.com/
http://www.kyocera.com/home.cfm
Anyway I'm enjoying the thread and planning on makin a lcd projector, but i still haven't seen a clear overview about what lenses and mirrors etc i should be looking for (have seen some dead ebay links and a few names of lenses but they don't make any sence to me)
I would really appriciate a clear overview with info about what i should b looking for and how it should be put together. I mean when i buy a 5,6 inch lcd display what sort/size of lences etc should i get and how should they be placed. Allso some more pics of the results wouldn't hurt ;) owh and if anyone needs some webspace to host their site or pics about this then don't hesitate to drop me a line coen@9worlds.net
tia ppl,
Axel |
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| Marklar |
| Well I called and asked a pro about the color filters and thier $20 each for 6X6 gel and it lets 2 stops of light through that is 1/4 of light (In Photo cameras) But he was not sure for 11,000 lumens of light because the 2 stops is the light actuly gling through the camera lens and to the film :/ so if you know what this will do to a HID light source please tell. My 2 lcd displays arived today and DONT buy one without a power supply!! The only place I could find a power supply for one of them is the people that sold it and they want $210 for one. |
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| cowanrg |
we need to either start splitting this thread into topics, or goto this guys forum he setup... this is gettting TOO huge, and ppl are posting just about everything. its impossible to find what you want.
http://talk.to/DIYprojectors |
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| kinsale11 |
Hi
I've enjoyed reading this forum and figured I shold share my results. I have gone the traditional route of LCD panel and OHP. I picked up a Sharp QA-1150 LCD panel off Ebay for $100 and a 5000 lumen Buhl OHP also from Ebay for $80. With my pc connected and a homemade screen completed I was ready to go. First of all a darkened room is needed but who really cares when the image (16:9) is sooooo big :) Anyway quality from DVD and TV from dScaler are great. Sure its not the most elegant solution but it works and works well.
Screen resolution is 640x480 which is a pain for your pc desktop with a 16:9 screen but hopefully the panel will accept a 640x320 resolution from powerstrip.
Anyway feel free to ask questions. I probably won't try photos as everyone says how crappy they come out.
Ian |
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| snoogans |
i too have gone the route of ohp, and i bought my panel of ebay for $40 (3m 4180) i got the ohp for $5.50 at a garage sale (suckers) for video source i use the aimslab jam. I have to say that my xbox is just awesome on this thing, all for a total cost of $70. Thanks to this forum, and the greenspun board, my home theater setup is great. i finaly have quality video to go along with my 5.1 surround system.
by the way, how old are all you people. (i'm 15) |
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| Scot_lad |
OK, I didn't know what a reflective LCD was, until now. Apparently all you do is stick a mirror behind the LCD instead of a light and you all of a sudden it reflects.
Doubt this is any use to anybody, just wondered if I was the only person who didn't know that.
And it's probably more complicated than just sticking a mirror back there.
Cheers, |
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| Axel666 |
Did anyone notice this thing?
Quarter Wave Plate - placed at a 45 degree angle to the optic axis to convert linearly polarized light to circularly polarized light to enhance the overall contrast ratio of the optical system.
Seems to me these could be really usefull to improve the final result of your projector allthough i haven't found a price yet. Anyone have more information on this?
Well I'll need to find a good display first :)
Just to let you know about the reflective 0.5 1280*1024 lcos displays they go amazingly cheap, just $250 a piece, BUT (yeah indeed there allways has to be a but) they only come in a 25.000 pack :( |
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| contrapasta |
Just wondering, I'm waiting for the VG150 I ordered to come(I got sick of retarded people overbidding on ebay, so I just bought a new one) And I was wondering what is the target color temp I should be shooting for in a MH lamp? Is there a color shift in the optics or LCD panel I should correct for? I also understand the MH has a certain brightness decline with age, does its temp shift down too? Some peoples' posts suggest 6,000 K, are these just guesses? Should I get the highest color temp possible (>10K kelvins?)
And on last thing, has anyone had the missfortune overpowering the lcd with light yet? Either washing the image out or burning the panel with too much heat. A lot of the disscussion early on in the thread was about using cold mirrors. Are these considered overkill now? I'm considering mirrors in my design to keep the size down... |
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| Marklar |
| The best color temp would be 5500 try to get a buld that is close to that as possible. As for loseing lumens MH bulbs will lose about half thier orignal lumens when they reach about 3/4 of thier life but they last so long and most MH bulbs are $50 and less but we have yet to find the perfect bulb. Well at sylvania I found a 4500K 9000 hour fiber optic bulb it is a focused point bulb but its not cheep. I put some in for some Sonic signs and the manager said they were about $300 but for 9000 hours thats not all that bad but the color still isnt perfect. |
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| Marklar |
This is a list of the places you will find the bulb we need, if you cant find it here then I don't know what to tell ya.
Sylvania Bulbs
Here you can search or browse thier database of all thier bulbs.
GE Lighting
Here you can download PDF's of thier bulb catalog.
Phillips Lighting
Here you can download PDF's of thier bulb catalog. |
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| Hellfire |
Axel666
You posted about a polarizing mirror and I was just wondering where You found it?
As Scot_lad mentioned a fiew posts back, I olso think the secret to a good projection can be some well placed polarization.
I think that a polarizing glass or mirror can help both before the LCD and after if it is used correctly becouse a polarizing glass can filter any strey light (from a wide lightsource for instens) and by that get ridd of the blured image.
Bye for now |
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| gav |
might be of some use to someone...
tp://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=1344922693 |
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| Axel666 |
| quote: | Originally posted by Hellfire
Axel666
You posted about a polarizing mirror and I was just wondering where You found it?
Bye for now |
The thing i meant was the quarter wave plate, if you look at the figures on this site:
http://www.spatialight.com/Technolo...lor_methods.htm
You can see that there is one in every setup, as far as i understood it was used to increase the contrast. I did find a site where they sell them but no prices, I'll send them a email tonight (haven't got the link atm, its on my laptop) |
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| fender4 |
For anyone interested, here is an update on my progress so far (rambling post :eek: :
I am using the nView Spectra C panel with an LOA 65watt Fluorex light and plano-convex (PCX) lens from www.surplusshed.com (it is 4.5" in diameter with a focal length of 12.5", item #L1593, thanks Gunawan for informing me about it). With just three parts, I can get a surprisingly clear, although fairly dim, image. I will make measurements of the produced image and possibly pics (if they turn out) as soon as possible. Without using a point-source light with a fresnel, I am probably losing a good bit of light as it is scattered to places other than the PCX lens. The apparent brightness should increase when I build an enclosure to house and contain the lighting. Right now, I am only holding the lens in front of the projector by hand (not very practical!).
I was surprised to find that the PCX lens alone could produce an image, because I intended to use it to gather the large image source to send to a Fujinon lens assembly. But after some thought, it made some sense. The image is clear, but the coloring is not optimised yet, because I think the "Macrovision" copy-protection is kicking in when I use the composite out on my DVD player. Hmmm. Maybe I'll try the s-video. Has anyone else had this problem? The brightness fades in and out sporadically.
I hope to build a nice enclosure and upgrade the lighting in the near future. Does anyone have a suggestion on enclosure materials (maybe from audio projects ;) ? I would like to stay away from wood--maybe steel sheets or aluminum.
Also, has anyone else seen the $20 MH bulbs at Home Depot? They are Philips 175w and 400w, but I'm having a hard time getting more info. Add that to a $44 ballast from elights and a socket, and that should be a nice, cheap MH setup.
The polarizing stuff is very interesting...keep us posted.
Good luck to everyone,
f4 |
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| Scot_lad |
I mentioned this a while back, could somebody back me up or knock me down about this?
I'm fairly certain that if you use RGB outputs instead of composite, you won't be bothered by the Macrovision copy protection. I'm not sure why you're having a problem in your setup though. The macrovision data isn't output in RGB, only composite.
Mind you, I only own a PS2 as far as DVD players are concerned, and that gives out RGB but I don't know if many other things do.
Hope this helps, |
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| fender4 |
Scot_lad,
When I get the Macrovision effects, I am using the component signal. I am buying an S-video cable today, so hopefully that will take care of it. With this DVD player, I experienced the same problem when using the composite signal fed into a VCR, so I am assuming it is the same thing.
-f4 |
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| jvisaria |
Another n00b here.
Took me 3 days to read all 87 pages of this monster, but I am pretty stoaked about the possibilities of having a small theater in my room.
Around page 30ish, I had in my mind the idea of:
LOA->Fresnel->LCD->Fresnel->Delta/fujinon->screen.
Now I am starting to learn a little more, and I am seeing the major drawbacks of the LOA lamps (no need to mention as they have been run into the ground pretty well) -- and now there is talk of the convex lenses instead of using whatever is in the fuji/delta lenses. Anyhow -- getting to the point:
Instead of using a convex lense after the LCD to 'gather' the image -- Could you use a fresnel? Im not sure what the impact of quality is -- but it might be a little more easier to work with.
It has been a few years since I had my last physics course concerning optics, and I didnt really pay much attention to that portion of the class because I was never to interested in it until now. A little help if you guys could!
Looks like this thread is really starting to mature and get into the technical aspects of what is being attempted.
Sorry if my post ran alover the place -- if anyone is confused please tell me and I will clarify. |
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| CanadianMike |
| quote: | Originally posted by snoogans
i too have gone the route of ohp, and i bought my panel of ebay for $40 (3m 4180) i got the ohp for $5.50 at a garage sale (suckers) for video source i use the aimslab jam. I have to say that my xbox is just awesome on this thing, all for a total cost of $70. Thanks to this forum, and the greenspun board, my home theater setup is great. i finaly have quality video to go along with my 5.1 surround system.
by the way, how old are all you people. (i'm 15) |
Hmm, I like the way your setup sounds. I have been looking for the absolutely simplest setup I could make. I am not looking for the most amazing quality ever, but I do want it pretty good (better than the 100 inch tv thing ;)) I was wondering, could I get an lcd panel, pop off the back, sit it on an OHP, and I would get something? I would think it would be a cheap, relatively effective solution. I hope someone would clarify if that is possible. Thanks.
Mike
P.S: If my idea makes absolutely no sense and wouldn't work (i'm a newbie with this stuff) could you point me in the right direction? Thanks again. |
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