| rmccoll |
| I just found that lcd while seaching on yahoo, i thought you guys might interested. I don't need it, I'm using the sony psone lcd screen for my projector, i want mine small, here's a picture of it. I'm using the Figinon lense from surplusshed. I had to build a stand for it, so it could be close to screen. |
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| slize |
the eyeglass thing works!!!!!!!!!!!!!!!!!!!!!!!!!!!
i've recieved my eyeglass today and first tests show that the picture is smaller; but the final test still comes, when i got my second projector finished...
i hadn't have the final distance but from the test it shows the picture is smaller and crystal clear and sharp... i will post pictures with the differences as soon as i have finsihed it...
@prjctr_builder;
if the lense from surplusshed doesn't work, the eyeglass thing is still a solution; mine cost me 11,50$ and in addition with my ohp lense i got the perfect picture from 7.78ft distance betwen screen and optic
just take a look at the top of the site; there i told u what eyeglass you will need to buy, but it is not for farsightly but short-sighted people as i learned ;-)...
slize |
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| slize |
| it is an eyeglass with -0,75 dioptrin for short-sighted people, 65 mm in diameter in my case... |
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| slize |
| nobody is interested in my solution for the focal length problem? with that you can position your projector at nearly every distance from the screen. and you always have the perfect (sized) picture... |
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| proto5 |
Slize:
How bout some screen shots?
How big of a diameter lens is it?
It's a big breakthru if it works!!!!!! |
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| dracul |
| Did you buy the 508mm lens yet? The suspense is killing me!!!! |
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| brainchild |
| quote: | Originally posted by slize
nobody is interested in my solution for the focal length problem? with that you can position your projector at nearly every distance from the screen. and you always have the perfect (sized) picture... |
I'm interested. Can you explain where you are positioning your new lens? |
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| slize |
please read the pages 106-107 there the idea is explained; but here is a short summary:
i am using a 3 lense ohp optic. the problem is the focal length is too short, that means the picture is too big at a distance of 8,75 ft to the screen...
the idea is to take a lense from eyeglasses at a certain dioptrin in additon to the ohp optic; i explained how to calculate that dioptrien number a few posts ago...
and used the program from the site prjctr_builder discovered...
the default setup is to put the lense right in front of the ohp optic, and by increasing and decreasing the distance it works like a zoom, because when there is room between the ohp lense and the eyeglass the focal length decreases and that means the picture goes wider... i am talking about max 0.8 inches between that two lenses... even this makes a differnce of 5 inches to the projected picture
i will post pictures as soon as i have finished my second projector with and without additional lense... i hope this will be next weekend :nod: |
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| brainchild |
| That's great Slize...good work. Keep us posted! |
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| dracul |
Slize,
Is the conclusion that the dioptrin aditional lens needs to be a convex concave eyeglass still or something else? |
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| slize |
please read the previous posts (site 106 and 107) and you'll get all the answers...
especially post #1590 + #1602 + #1603 |
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| dracul |
| So I want to use Alans 80mm diameter projection lens but the optic stores in my area only seem to carry 65mm diameter dioptrins. I really need 80mm diameter for no cropping to occur dont I? When can I order this online ? Alan do you have any sources near where you are? |
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| diylabs |
I don't have any good lens sources locally that I know of, but I will definitely start looking. Also, I'm having the condencer lenses made for me, so maybe if these newer lenses that you are all talking about really do work, then I can possibly have some of those made too.
Coincidentally, I tried using a 6" concave lens as a reduction lens so that I could use my projector further from the wall and it actually worked! The lens was just an $8 from www.surplusshed.com. It did distort the shape of the image very slightly though, but it didn't distort enough to make objects on the image look strange (it just simply made the edge of the image not quite straight). The addition of this lens before the projection lens (the 80mm triplet) made the image roughly 1/2 the original size. As soon as I get my projector working again I'll measure this effect with a tape measure and also take some pictures of it too now that my camera is working again. |
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| slize |
| you can get them lenses where you can get eyeglasses... is that so hard to understand? it is a normal eyeglasses... and the diameter has nothing to do with dioptrien... dioptrin is 1 divided by the focal length of a lense in meters... |
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| dracul |
| I went to a eyeglass store and they showed me a 0.75 dioptrin organic lens. It was only 65mm diameter. If I place this infront of my 80mm diameter projection lens will the image not be cropped? |
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| slize |
don't know about that but i don't think so, as 80mm diameter for an optic is really big...
BTW what focal lenght is your 80 diameter??? i see you didn't get it, how to calculate the dioptrin YOU need... because you tell me something about a 0.75 dioptrin glass. first of all I took a -0,75 dioptrin glass and the focal length of my lense is 290 mm and wanted a 1.54 m projected picture at a distance of 2.4m...
and for example prjctr_builder would need -1.125 dioptrin glass because his existing lense has 320 mm fl for his specifications...
so PLEASE DON'T go and buy a -0.75 dioptrin eyeglass just because it worked for me... make you own calculations and you will get the lense you'll need...
the basic idea is to use eyeglasses because they can be calculated and they are cheap...
just take the example i made and you will get your dioptrin right... and talking of 0.75 dioptrin, this would make the existing focal length of your 80 dia lense only bigger and that would mean you will even get a BIGGER picture
so please read the post and read 'em carefully and switch your brain on and once again you'll get all the answers... |
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| diylabs |
| quote: | Originally posted by slize
you can get them lenses where you can get eyeglasses... is that so hard to understand? |
I understand that, but I work and take classes during the day, and I also live in a very small town, so it's not that convenient for me to get parts from an eyeglasses store that is only open until 6pm. |
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| dracul |
Slize,
I did do my own calculations and ended up with a positive 0.66 result. I know it should have been negative but I got positive.
1/0.317 (focal lenght of my lens from diylabs)
1/0.423(focal length of desired lens)
1-2 = some negative number (but not in my case) . Are these not the instructions? |
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| dracul |
Alright its 2-1 or the ideal focal length dioptrin minus your actual lens dioption. I could swear I saw someone post instructions as 1-2. Never mind. I appologize. Brain turned ON now.
80mm diameter is the lens from Alan diylabs. Its focal length is around 317mm I think. Bigger diameter the better is it not? More light etc..... |
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| cohort36 |
I don't mean to change the subject away from the eyeglass lens stuff, but I need some ideas/advice for a reflector.
prjctr_builder:
Any luck on getting your reflector plans/diagram up? You mentioned doing that a while back, and I was wondering if you were still planning on doing that. |
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| slize |
your calculations sound right.
i will open a new thread on how to calculate the additional lense... but for now here is a short discription:
1. go to this page http://www.opsci.com/index.asp?page...hCalc&exten=htm
fill in your specifications... then you will get and Maximum focal length of lens:
2. take the focal length (fl) of your existing lense in meters. then divide 1 by fl in meters
you'll get something like 3.xx (example)
3. take the Maximum focal length of lens in meters. then dive 1 by it
4. now take 2. - 3. and you'll get and negative number.
this is th edioptrin you need
5. in Europe they have 1/4 steps so take the dioptrin that is closest to your number (for example -0.8 --> -0.75)
in the US they have 1/8 steps same thing (for example -0.9 --> -0.875 )
that is all... |
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| brainchild |
4. now take 2. - 3. and you'll get and negative number.
Nope a positive number...
Slize in your earlier posts you have us subtract your existing lens from your ideal lens...
that means my adiotnal lens must have 2.6(ideal) - 3.45(existing) = - 0.85 dp
In you last post you have us subtract the ideal from the existing...
2. take the focal length (fl) of your existing lense in meters. then divide 1 by fl in meters you'll get something like 3.xx (example)
3. take the Maximum focal length of lens in meters. then dive 1 by it
4. now take 2(existing). - 3(ideal). and you'll get and negative number.
Number 4 should actually read "take 3 - 2 and you'll get a negative number."
Probably just a typo but confusing... |
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| prjctr_builder |
i got the 508mm fl objectives i ordered, they do make the right size image where i want it, but the corners are messed up, i will need to play around with it over the weekend and see if i can get something going...
dammit...
the screen is the right size though, so you formulas DO work!!!
muahaha
aleksey:nod: |
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| brainchild |
So I decided to try out this zoom thing. I did the calculations and came up with a number to put my projection on a different wall in my room, just for the hell of it. I figured I would need an eyeglass with -1.125 diopters. I called around, MalWart hung up on me, LensCrafters said they could do it with a prescription..hehe..I told them it was for a science experiment and they said 'OH...come on in it's free.' I get there and they're looking at me thinking, 'this guy is too old for highschool,' (I never mentioned school at all) but they begrudgingly give me the lens for free. ;) They did grill me about what school I went to etc, I just told them the truth. I asked the guy how much it would cost if I wanted to buy it he said...'a lot..$60' heh.
I run home thinking I'll slap this thing on my lens triplet and watch my picture shrink...WRONG. All I get is a big blur..newsflash..you can't increase a len's focal length without moving that lens that much farther away from the object. So I grab my objective and put it 8"-10" farther out from the hole in my box, throw the eyeglass on and bingo, smaller picture, much smaller...and my calculations proved correct, my image was 9' horiz at a distance of 15'. Anyway, this led to a rash of questions about my fresnel, how I could even achieve a projection so far away from my collecting fresnel, why my projection was still oriented correctly, and how the hell I'm going to modify my box to include that extra distance. Man I figured I had a good handle on the theory of my optics, surprise. Guess who will be taking the MIT online optics course this week? |
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| slize |
| same thing with my eyeglasses projctr_builder... must to have something to do with the fresnel lense; i'll check that out in the next days... |
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| slize |
| what focal length does your fresnel etc have? because my picture is smaller, but the edges or not bright enough... do you use a 15" tft or smaller? hmm... i feel i am on the right way but for now i didn't find the perfect solution for me... just as i said, the fresnel has something to do with it i just didn't figure out yet... |
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| slize |
| quote: | Originally posted by brainchild
4. now take 2. - 3. and you'll get and negative number.
Nope a positive number...
Slize in your earlier posts you have us subtract your existing lens from your ideal lens...
that means my adiotnal lens must have 2.6(ideal) - 3.45(existing) = - 0.85 dp
In you last post you have us subtract the ideal from the existing...
2. take the focal length (fl) of your existing lense in meters. then divide 1 by fl in meters you'll get something like 3.xx (example)
3. take the Maximum focal length of lens in meters. then dive 1 by it
4. now take 2(existing). - 3(ideal). and you'll get and negative number.
Number 4 should actually read "take 3 - 2 and you'll get a negative number."
Probably just a typo but confusing... |
yes you are right... :cannotbe: it was late when i posted that :) so 3. - 2. is correct |
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| brainchild |
| quote: | Originally posted by slize
what focal length does your fresnel etc have? because my picture is smaller, but the edges or not bright enough... do you use a 15" tft or smaller? hmm... i feel i am on the right way but for now i didn't find the perfect solution for me... just as i said, the fresnel has something to do with it i just didn't figure out yet... |
Using a fresnel FL 330mm
15" LCD |
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| slize |
i have a new idea; what are these plastic things behind the lcd called?
everyone who has taken apart an PC monitor TFT has to find such a thing. May we can use it??? i thought instead of this cfls with a "low" light lever, we could use our MH, HQI, HRI or whatever bulbs and build a thing that we backlight our tft s... that would solve the probs with the fresnel lense and may be then we can use our optics with the adoppted focal length??? as i stoped building my second projectorm because i want to make it compact i will try this solution. let me know what you think of that.
this idea comes from the basics of this 100" seller things, because there u can project a (dark, not sharp) picture, but without a fresnel... maybe that would solve our probs with the size of our projectors.... |
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| slize |
| it has defently something to do with the fl of the fresnel lense (i took an older fresnel from an old project which is splitted and i got more picture at the right size; but still not the full...) i will search for a way to calculate the right fl of the fresnel for our new lenses and i am sure then it will work. i will think about it for the week end... |
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| mhelin |
| Slize, move the light source closer to the fresnels, it will do it. |
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| slize |
| as i read from other threads this two sided fresnels have to different focal points. one for the bulb one for the optic. i looked for it at the splitted fresnel and damn it was right. the one had 330mm which was the dictance for the bulb i had and the other had 280mm which was the distance for the optic i used, as my optic has a fl of 290mm. that would mean i have to turn around the fresnel move the light closer to it and give it another try with the additional lense... |
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| slize |
| but i don't think it s that easy, i'll have to make more calculations... |
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| diylabs |
| actually yes it is that easy ... |
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| declined |
Ouch...
I -finally- found a shop in Belgium where I can order a MH bulb + ballast, but it seems rather expensive, especially compared to prices in the US:
250Watt bulb: 61€
400Watt bulb: 90€
250Watt ballast: 150€
400Watt ballast: i didn't want to know anymore
(€ is about the same value as $ for the moment)
-sigh- i wanted to get a 400watt setup but our prices seem to be like 3 or 4 times higher than US prices :(
are there any people from belgium or the netherlands on this forum who know about cheaper shops? |
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| dracul |
| Alan, please check your email. |
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| slize |
| quote: | Originally posted by declined
Ouch...
I -finally- found a shop in Belgium where I can order a MH bulb + ballast, but it seems rather expensive, especially compared to prices in the US:
250Watt bulb: 61€
400Watt bulb: 90€
250Watt ballast: 150€
400Watt ballast: i didn't want to know anymore
(€ is about the same value as $ for the moment)
-sigh- i wanted to get a 400watt setup but our prices seem to be like 3 or 4 times higher than US prices :(
are there any people from belgium or the netherlands on this forum who know about cheaper shops? |
may be MH bulbs are so expensive because they are imported from the us. here in germany/europe we usally use "hqi" "hri" "hmi" and so on. they are equal to mh-bulbs...
may be you should look for that in belgium... i got my complete set for 59€ plus shipping... a brand new bulb costs 65€ but on ebay i got it for 25€... |
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| slize |
| quote: | Originally posted by diylabs
actually yes it is that easy ... |
nope it's not; i made my calculations and i made 'em good as my test shows because it works...
here is a short sketch and a link to a program that proofs it http://www.mathe-online.at/material...rahlenoptik.htm
go on "Sammellinse" to see what i mean |
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| slize |
so first of all: a fresnel has ALWAYS two focal points one on each site at the SAME distance no matter if it is made out of two glued together and each at a different focal point. the new focal point is then 1/focal length of first in meters + 1/focal/lenght of second in meters = 1/new focal point ===>> reciprocal value and you have the new focal point...
now to the problem with the additional lense: the reason we only see a small point and not the whole picture lies in the fact that our optic has now a new focal length and lies behind the second focal point (i know it is not right but ii call it like that because it is easier, you can see in the sketch what i mean...)
to see the full picture this above must be and the bulb must be behind the second focal point on the other side of the fresnel; you can take a look at the programm i linked then you can see what i mean: go to "sammellinse" and you'll see what i mean
so we need a fresnel lense that has the specs like the last sketch, that means twice the focal point must be longer than the focal lenght of our new optic and the bulb must be placed behind that. i got that by splitting my existing fresnel lense. one had 13.78" focal length and the other 12.6" (that's why 6.5 before). so i got one. and the distance will be solved by mirrors... |
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| diylabs |
| Yeah - I can sell you a complete 250 watt HQI kit with sockets for $150 in USD ... shipping (4-10 day airmail with USPS) would cost $24. That makes it a little cheaper than buying it locally, but you'd still have to wire it since I don't know what type of plugs you use in Belgium (the ballast can be 220v though). I have a person in France who buys some of my lenses in larger numbers to sell in bulk to other people in France - that saves everyone on shipping big time! If anyone wants to do the same for the ballasts, then just let me know. I can usually get quantities of 10 ballasts within about 1 week of ordering them (I don't keep that many in stock usually). Email me at diylabs@hotmail.com if you want to talk about doing something like that with any of the parts I carry. It would be very nice if we could get this going in multiple countries because I know that shipping 10 units all at once is a lot cheaper per unit than shipping 1 at a time, although shipping to the Netherlands is actually not too expensive! |
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| declined |
| quote: | Originally posted by slize
may be MH bulbs are so expensive because they are imported from the us. here in germany/europe we usally use "hqi" "hri" "hmi" and so on. they are equal to mh-bulbs...
may be you should look for that in belgium... i got my complete set for 59€ plus shipping... a brand new bulb costs 65€ but on ebay i got it for 25€... |
hqi, hri, hmi... do these bulbs have the same specs as mh? Especially concerning heat and "being point-source"?
I assume they use specific ballasts?
-> do you mean those are easier to find in Europe? |
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| slize |
| yes they are, look for aquarium stuff, there you will find hqi lamps. i use a "OSRAM Powerstar HQI-TS 400W/D" with 36000 lumens and a bulb life of 9000h (manufactor) |
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| declined |
Hey thanks! Thats some great info!
I hope I'll find one of those around here but i think it should be no problem because there is a very big aquarium shop in the neighbourhood here...
I'll stop by this afternoon and let you know if i find anything |
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| declined |
| sorry i was kinda sick today i'll go tomorrow or wednesday for sure! |
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| Javata |
Great declined, i live in Holland and also looking for bulbs an balasts, so keep us posted.
Maybe you can tell me also the name of the shop, so i can visit them also, if you have good results.
What are the specs of youre diy projector?
greets |
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| mhelin |
| quote: | Originally posted by slize
so we need a fresnel lense that has the specs like the last sketch, that means twice the focal point must be longer than the focal lenght of our new optic and the bulb must be placed behind that. i got that by splitting my existing fresnel lense. one had 13.78" focal length and the other 12.6" (that's why 6.5 before). so i got one. and the distance will be solved by mirrors... |
You don't need a new fresnel with longer focal point if you just move the bulb closer to the fresnel and the fresnel will project the light further towards your projection lens + eyeglass combo. Some OHP's have a such adjustment for the bulp assembly, I think. Obviously a longer FL fresnels helps, but on the other hand the closer distance between bulp and fresnel may in fact make the image brighter, though if it's too close to the fresnel the angle between fresnel and light ray's may become too big and some of the light will be reflected away making the picture dim in corners. I think about 8" is the closest distance* between bulb and fresnel which you can use. If you take the bulb further then you better use a condencer lens.
*) for 15" LCD or about 12"x12" fresnel |
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| dracul |
Brainchild,
Just want to confirm once you added the dioptrin lens you were getting a sharp even image with brightness and everything edge to edge?
What diameter is your dioptrin? What diameter is objective projection lens? |
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| dracul |
Brainchild,
"So I grab my objective and put it 8"-10" farther out from the hole in my box"
Your beamer looks pretty long already. How long would it be if you added the extra 10 inches between second fresnel and objective/dioptrin combo? |
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| lativiana |
I know a litle bit concepts about building this projector. but the big problem is that I cannot find the LCD panel like Sharp QA-1800 in my country (surakarta, Indonesia). So I think to find any alternative panel like tv-lcd portable (Casio tv mobil for example). But the most problem is replacement the panel from its cabinet.
Can anybody here help me to do this ? or tell me other alternative
with this !
Thank You |
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| dracul |
I am being told that the maximum diameter eyeglass lens you can get anywhere is 65mm.
Brainchild Is this what you are also did the test with? Is your Projection lens not 80mm? No image cropping? |
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| declined |
| Ok... once again I didn't get the info from the aquarium shop because the owner wasn't there that day and his son didn't know anything about the bulbs-> monday I'll go back and ask the owner himself... |
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| slize |
| i gave up!!! this picture thing doesn't work for me... :mad: i decided to built my projector as light as i can and to put it onto the ceiling at the distance i need... damn calculations, they were right, but they weren't practical. next friday i'll make a vid night and i need the damn projector so i'll decided to give up on the calculations... sry @ all... |
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| Storhemulen |
Hello there!
I'm a long time lurcher (since thread 1).
Just got back here to check things out.
There's been great progress!
Anyway, for you dutch guys looking for cheap MH lamps, they can be found in the nearest canna-growshop...
Smokeys are cheap.
I know that the rest of their gear is not what would be called morally correct where I live, but who really cares?
;)
Good luck guys! |
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| Faites777 |
I have seen light source reflector for HQI bulb from soup ladder to large spoon. Has anybody try to used a PAR bulb or similar bulbs as a reflector? It's has a "perfect" reflector.
Just get a dead bulb, clean out the inside and make the HQI fits. |
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| mhelin |
| quote: | Originally posted by slize
i gave up!!! this picture thing doesn't work for me... :mad: i decided to built my projector as light as i can and to put it onto the ceiling at the distance i need... damn calculations, they were right, but they weren't practical. next friday i'll make a vid night and i need the damn projector so i'll decided to give up on the calculations... sry @ all... |
Yes, the keystone correction with the condencing fresnel (the one between TFT and pj lens) works pretty well.
Btw. It's a must for anyone using dismantled monitor to split the OHP fresnel (or use two single). Also anyone with OHP and dismantled TFT monitor should do the same. Propably the pj panels use different LCD panels, but at least with my BenQ FP567s (same panel as in FP557s) the condenced light (from usual double fresnel) makes the picture unevenly light, distorted in colors and dim. This is because the contrast in TFT is best with collimated light source, the light which hits the panel in other than 90 degrees angle just spoils the picture. |
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| mhelin |
There is now at least one proven design that works for building a DIY projector with excellent results:
1. Use a dismantled TFT monitor (approved list of monitors: CMV1515, 1512, BenQ FP557s or FP567s) as the panel and controller. You'll get the native XGA resolution with a good contrast (500:1) and good colors (look for real 24-bit color, though the 18-bit 'dithered 16.2 million' will work almost as well).
2. Use a 'split OHP fresnel' or two single sided fresnels, one for collimation (between the lamp and the panel) and the other for condencing (between the panel and pj lens/mirror).
3. Keystone correction can be done by tilting the condencer fresnel.
4. The pj can be mounted on the floor or onto the ceiling so it's out of way.
5. You can buy the fresnel and the triplet lens from diylabs.org
6. Use a 250W HQI double ended metal halide lamp (like OSRAM) with color temperature of 4200 K or 5200 K. If you use the condencer lens you can use 150W CMD lamp (like Philips) which have better CRI (color rendering index) than the 250W HQI.
7. Use a reflector behind the lamp, it has to be spherical, nothing else works! For and example a soup laddle works well if it's (almost) perfectly round.
8. Optional: Use a concencer lens on top of the lamp with a large diameter (~80 mm) and short (~100 mm) focal length.
9. Optional: Use mirror to mirror the image before pj lens or after it. Closer to the pl lens it is the smaller can it be. If you don't use mirror you must be able to mirror the image by using the TFT 'wrong way' - not recommended as the TFT may have a transreflective polarisation filter on it's l'ight source side' but not on the 'viewing side'.
10. Mandatory: Use cooling for the lamp and the panel. Four regular 80 mm fans are enough (two blow in, two out) , maybe two that just suck the air out from the box.
Ok, that's it, get the parts and build the projector. Now let's see who's got the simplest design pj that's built after all these 'rules'.
Btw. We should now write sections on how to dismantle the monitor and how to split the fresnel, right? Also some good technical drawnings were useful (with mirror, without mirror, for ceiling mounting or for a floorstander). Also good photos on different technical solutions for TFT and fresnel mounting, cooling etc. |
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| dracul |
| quote: | | If you don't use mirror you must be able to mirror the image by using the TFT 'wrong way' - not recommended as the TFT may have a transreflective polarisation filter on it's l'ight source side' but not on the 'viewing side'. |
Are you saying a mirror is mandatatory unless I want to put the lcd the wrong way? |
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| dracul |
| I want to build my beamer and later add a condenser when available from diylabs. Will things have to move and will the box have to be longer or shorter? |
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| mhelin |
| quote: | Originally posted by dracul
Are you saying a mirror is mandatatory unless I want to put the lcd the wrong way?
I want to build my beamer and later add a condenser when available from diylabs. Will things have to move and will the box have to be longer or shorter? |
Only software solution that works (with HTPC) to mirror the image is Dscaler. It can't play DVD's and DivX (correct me if I'm wrong, maybe it can?). Also there might be a codec (like DivX codec or any other codec) that mirrors the image (www.montivison.com, MV Mirror Directshow filter costs 49 EUR +VAT btw.) , so with a software that lets you manually connect the WDM filters to 'build the graph' (Zoom Player?) you could also watch DVD's or DivX.
With condencer lens (or any other lens) the inversion of total focal length is the sum of the inversion of the two other focal lengths. So practically 'things have to move' closer to the fresnel. |
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| dracul |
This is the first time I am hearing that you need to mirror the image. So with no mirror physical or software I will have an upside down image correct?
Didnt Brainchild build his beamer without any mirrors? I dont remeber him mentioning anything about this problem.... |
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| dracul |
| quote: | | so with a software that lets you manually connect the WDM filters to 'build the graph' |
What are WDM Filters?
Did some reasarch and found Zoom player accepts directshow.
There is also Sonic Cineplayer dvd player
What about ffdshow filters? Do they have a mirror filter option? |
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| mhelin |
Like I wrote you can (as Brainchild did) turn the TFT panel over and use it the other way which effectively mirrors the image. However, if it's designed to be used one way it's quite logical to assume that the other direction isn't recommended. For an example there may be heat problems. Also if you dismantle a monitor like the BenQ FP567s the electronics (pcb's) come out such way that it's easier to use the panel in it's original position (regarding the position of the light source).
The Directshow filters are WDM (windows driver model) filter drivers. The older standard (now obsolete) for video in Windows was (surprise) Video for Windows (VFW), and these are not compatible. When you open video (or audio) device in Windows (practically some application) the WDM filter graph is built automatically by the application. With Zoom player you can also manually add new filters (like the mirror filter) into the graph (between some other filters, all codecs like DivX or DVD are also filters, it's 'WDM language', look for Windows DDK or DirectX DDK in Microsoft.com site for all used terms). |
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| Mavmesa |
mhelin
I have the fresnel (different focal lengths) and the tripet lens from diylabs. I have a NEC 1545v that I have disassembled and I use a 400W MH full size bulb. I am interested in splitting my fresnel, but am unsure of the distances between the different parts. I do not have a condensor lens. What distances should work best if I split the fresnel lens?
Someone please give me a definition of a condensor lens. I assume that a condensor lens takes the light souce on one side and makes it appear smaller and brighter to the fresnel lens. Is this true? Can someone explain the principle and how it results in a brighter image?
Mavmesa |
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| elstcb |
Have just been experimenting with different bulbs, some of which have an orange or blue tint and have thought of a very easy way to correct this - by painting the wall a slightly off white colour.
For example if your bulb looks slightly orange then painting the wall a very light turquoise colour should correct this for you as more blue and a bit more green will be reflected than red.
Clearly this is going to make the projected image slightly dimmer as less light will be reflected but it should be easier and cheaper (in true DIY fashion) than using colour correcting gels.
Just a thought anyway.
Steve |
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| dracul |
Or you can use a color filter infront of your lens or somewhere inside your projector. There are a lot more choices of colors and suttle colors to choose from. If you really got a lot of light you can even use contrast filters to increase contrast. There are color enhancing filters to give you richer and more saturated colors.
www.rosco.com (look for roscolux)
www.leefilters.com
They both have these swatch book sample kits which have samples of every filter in a small book. Some are big enough to use infront of your pj lens. The sample book is free. Go to a Movie lighting place in your town or a pro photo store where they sell lighting gells and they will have these. If you must have a larger sheet a 24"x24" sheet is about $5.
Panavision is a know movie shop chain that will most likely have them in your town. |
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| mhelin |
Here is a picture for my older
message (can't edit it for some reason). I can't recommended any other design, you can use fs mirror but you don't have to - the image can be flipped with software like Zoom Player Professional (needs DirectX 9). Also the split fresnel shouldn't be an issue anymore as diylabs.org is selling 12.2"x 12.2" fresnel with FL of 8.6" / 13" pre-split. With split one (two separate fresnels) you get MUCH brighter and evenly bright image and MUCH better colors. New TFT's just don't work well unless the light beam hits the panel in 90 degrees angle (~light rays are collimated). PLUS++ you can easily implement a small keystone correction by tilting the second fresnel, and get the projector out of view (keystone correction can be horizontal and vertical at the same time, so the projetor can reside for an example on the floor on one side wall of the room leaving plenty of room for the audience). |
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| dracul |
| Will the mv directshow filter work with a tv tuner software and card? |
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| mhelin |
| quote: | Originally posted by dracul
Will the mv directshow filter work with a tv tuner software and card? |
I couldn't get the mv filter work at all. Use Dscaler for TV and Zoom Player for everything else. |
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| dracul |
You paid for the mv directshow filter and it didnt work?
How are you finding the quality of dscaler?
You have to buy or use zoom player pro to use with dvd right? Also, I need a directx9 compatible video card which start at $100 usd right? |
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| mhelin |
| I used the free demo version, for some reason MV Mirror didn't show to ZP. ZP Pro costs just $19.95, DirectX 9 cards start from 75 EUR (the crippled FX5200, or an ATI Radeon 9000 card). I'm not 100% sure if you need Dx9 card or is it enough if you just have DirectX 9 runtime installed. Anyway you must be able to use VMR9. There's nothing wrong with Dscaler, the quality is as good as the quality of your TV card, and much better than with the TV software that comes with those TV cards. Just enable the comb filter and 3:2 pulldown and adjust the colors, and enable the Mirror filter if you have a pj that needs it. |
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| mathias |
| A replay to Faites777, I did a test with a big Halopar 30. I cut it and placed my hid-lamp in the middle. I´m sorry to say it didn´t work, becaurse the lamp only lights up the middle of the 15" tft, with the 30 degrees lamp and there aren´t any wider degrees for that lamp. |
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| mathias |
| In my pj design I instead use a 60 degrees small halogen bulb with coollight reflector. I cut it and placed my hid-lamp in the middle. And it works great ! Very bright with only 150 W. And becaurse the coollight reflector, you can almost run it with no fans. |
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| Negative Design |
nice ...very nice
how much did it cost to do it? overall |
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| mathias |
I think...
2 anglesteel $2.
2 Halogenholder GY6.35 $8. (Don´t need if you have a HID-holder).
1 Halogenbulb 35W 60 degree coollight $6.
Some screws from my junkbox. And of course you need a drillmachine, jigsaw and a glascuter, but that is normal things most people already have. So around $16, I think I spend to make it. |
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| dracul |
Ok. What happened to Brainchild?
He reported that the diopter he tested worked great he just had to make another box. I asked him what the diameter of the diopter was and the guy disappers. I will be receiving a 80mm diameter pj lens but I can only find 65mm diopters. Can someone tell me if this is gonna work before I buy it? Will the light not be cut down at least if not the image itself?
What if I put it on the inside of the projector housing?
Has anyone else has success with this?
Is the image quality compromised? |
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| Mavmesa |
mhelin
I have redesigned my projector, split my fresnel into 2 parts, and duplicated your layout (except for the condensor and the reflector). I do have the 80mm triple, and the 8.8/13 fresnel from diylabs. I cannot get any increase in brightness nor does the lighting even out anymore than before.
Please give me the distances between your optical components so that I can duplicate your setup "exactly" and see if there are any benefits to splitting the fresnel.
Mavmesa |
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| mhelin |
mavmesa,
What type of panel you use? It is possible that some LCD's (like my dismantled FP567s) absolutely require two fresnels (collimated, straight light rays though the panel). My distances are ~8.8" from the bulb to the 1st fresnel, the second fresnel is next to panel, tilted for keystone correction, distance between LCD and pj lens is about 10"-12" (I use the shorter FL pj triplet from diylabs, same frensel as you). Check that you have the grooves of fresnels inside. |
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| mhelin |
I think we can't improve anymore this design. Though I'm happy with mine I'd like to use a smaller (~150W) bulb but there are no wonder reflectors or condencers available that could make it possible to use 100% of light for projection. There are only small improvements to be made, maybe 10% brighter image with better quality components (or with less components like without mirror). Maybe in future there will be LCD's that let more light through when ON and less when OFF improving both contrast and brightness. Till that day nothing can be done to make things better.
Btw. I've seen TFT monitors (17") with 800:1 CR, how would that be? Sanyo PLV-Z2 will have CR of 1300:1 even when it's LCD and not DLP. |
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| Mavmesa |
I am using the NEC 1550V. There is no discernable difference in light output. Possible our difference is that your panel is more picky about the angle of light entering it.
I will stay with the new design as it is more flexible. Since I have split the fresnel, I now have debris on the grooves and seem inable to remove it. Any ideas? |
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| Faites777 |
I will be using a standard 400W MH bulb (BT37) in my DIYproj.
The bulb produces alot of heat and this is a concern for me.
I plan on using a glass plate to block the heat from reaching the LCD. Added on is a 92mm fan to pump the heat out of the enclosure. The only thing missing is an IR filter to eliminate the heat radiation(light).
1) Where can I get an IR filter that's 12''x12''? I plan to use automotive tint (<50%) since it's cheaper.
2) Do I really need all of this add-ons? Will the fresnel melt with only a fan in the system? Does the DIYLABS fresnel turns yellowish over time? |
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| [RPD]-Killer |
Well, I have heard so many things about fresnels and the size of a TFT, but for now, I want to make it really clear.
Is there a fresnel lens with dimensions of 304.1 x 228.1 mm in order that every pixel of the 15" TFT is displayed on the projection?
Forgive my sucky english, need to practise more. Reading is absolutely no problem, but when it comes to write... :xeye: |
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| mathias |
| I did some update on my project. First I changed the 60 degrees bulb. Now I use a 10 degrees bulb instead, the picture gets much brighter and sharper, becaurse it didn´t work in that way I thought. It works as a normal OHP-setup, but this design is much more effective, you don´t lose that much light that you do in a OHP. If you use a single-ended HID-bulb, I think this design is the only you can use if you want all the light from the bulb. I can tell you it´s much brighter than the normal OHP-design other people use. You can use a condenser lens if you want it even brighter. The bulb I use is a "Philips CDM-T 150W" you don´t need more light. So give up your soup-ladle design ! |
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| mhelin |
Just found that for many LCD's the optimum vewing angle is not a straight angle. Instead some datasheets list 6 o'clock or 12 o'clock optimum vieving angles. I'm quite sure my AUO M150XN05 has an optimum viewing angle at 6 o'clock. That means that as a direct view monitor you should look into it at some angle below the midpoint.
M150XN05 lists viewing angles U/D 40/60 which gives a hint to optimum vieving angle being at 6 o'clock. |
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| mhelin |
So practically this means that the best possible contrast for a LCD panel is not achievable at 90 degrees angle but less, and the LCD should be tilted. However, that is not bad thing as you can watch your DVD anamorphic and let the LCD tilt take care of the vertical shrinking of the picture so there's no need for an anamorphic lense anymore.
Note that tilting the LCD is just an idea I haven't tested yet (will do it later). I hope that I could increase the contrast from about 400:1 to ~600:1 with my LCD using that kind of arrangement.
(btw. the LCD tilt in picture is for an LCD panel with 12 o'clock optimum viewing angle, you got to think it yourself which way you should tilt your panel) |
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| mhelin |
Maybe I was too optimistic.
Here at page 2, 2nd graph you will see the viewing angle vs. contrast ratio measurement for M150XN05 panel (from BenQ FP567s). At 0 degrees it's only 300:1 and at ~ 12 degrees towards 6 o'clock it hits it's maximum value of 450:1. I haven't calculated yet how many degrees tilt is needed to shrink anamorphic picture (720x576 PAL DVD) in 16:9 to 4:3, but it may be more than the 12 degrees needed for maximum contrast. It's still possible to adjust the picture in software, another option is to build an anamorphic lens that shrinks the rest of it.
Another interesting note on that document was that on LCD brightness when LCD is in power OFF state vs. when the LCD is on and displays white color. It's surprising that the screen (normal mode) is brighter when the LCD is in power of state. If the controller is properly designed the difference is no more than 10% (still quite a lot).
Original M150XN05 datasheets can be found
here. |
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| dracul |
Excellent catch. I am assembling shortly and will try this out.
Tell me more about the software option for anamorphic. How come no one has mentioned this yet? I thought the anamorphic issue was more involved than just tilting the lcd?
Also what about focus eveness if we tilt the lcd? |
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| mhelin |
| quote: | Originally posted by dracul
Also what about focus eveness if we tilt the lcd? |
That may be a problem, though in my theory you don't focus to LCD but to the fresnel on it (or slightly behind). However, if you tilt the LCD 10-15 degrees it's almost the same amount (also the same direction with M150XN05) as you do for the keystone correction with the fresnel.
You can view DVD anamorphic practically with all DVD (software) players (PowerDVD etc.). Some players allow you to choose almost any scaling. Maybe it's worth of getting some real test DVD for tuning or burn own test CD / DVD /DivX CD/VCD CD etc. |
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| mhelin |
| quote: | Originally posted by jj0ns0n
Hey mhelin. Interesting posts on this subject. Although, I was reading up on what u had posted and it looks as if the datasheet refers to the LM0310C150 and not the M150XN05. Different LCD right?
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LM0310C150 *IS* the M150XN05 LCD with Maxibright backlight. |
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| ace3000_1 |
yeah ive thought in your ideas and still have a few tests to cunduct on the lcd tilting for contrast and brightness, i thought in tilting the lcd forward as then a brighter picure comes out but then the contrast goes and so does the colour, if u tilt it back then the screen goes the opsite way and gets darker and u get more darker contrast, personally i found 0deg the best as in looking strait into it but i think just off set u could be onto somthing here, as i said i havnt fooled with this too much so your da man in this, keep us posted and let us know on your findings,
as for those who dont know the front of a lcd is a vertical polarity and the back is horizontal, manufactures do this on purpoise because the veiwer normally sits right infornt of the screen and not to the side, how ever a lcd will work with the polarity in the oposite direction and some are projuced for certain aplications but the majority are as stated above.
Trev |
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| jj0ns0n |
| Since we are not using the a backlight (where light spreads equally across the screen), would this subject apply to projection diy'ers? There's several reasons why there would be a loss of light when tilting the screen (in theory). |
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| rmccoll |
| Has any of you guys thought about using fiber optic? I was watching This Old House Classic and they showed a track lighting device were 250 watt quartzs light bulb transfered light to8 fiber optic cables. The light came out of cable was really bright, this could probably be used with a small lcd, Idon't know if it would transfer the heat from the bulb through the cable or if the cable causes the intensity of the light to decrease. Just thuoght I'll this concept around. |
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| brettcarel |
I am looking at building a projector for my brother and was looking at Ballasts. I looked at the diylabs.com and saw that they sell the IceCap ballast. Does the brand of ballast make a difference? The IceCaps are quite expensive yet I have seen others on sell through ebay and other places that are much cheaper.
Thanks! |
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| 18wheeler |
| quote: | Originally posted by rmccoll
Has any of you guys thought about using fiber optic? I was watching This Old House Classic and they showed a track lighting device were 250 watt quartzs light bulb transfered light to8 fiber optic cables. The light came out of cable was really bright, this could probably be used with a small lcd, Idon't know if it would transfer the heat from the bulb through the cable or if the cable causes the intensity of the light to decrease. Just thuoght I'll this concept around. |
yes. and was determined to be too expensive for diy. look back the original DIY video projector thread. |
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| mhelin |
| I calculated that tilting the LCD 12 degrees needed for optimum CR with BenQ LCD will have little effect to picture height. It will shrink from 228 mm to 223 mm which is practically unvisible. For anamorphic correction (4:3 -> 16:9) you have to tilt the LCD 41.4 degrees which makes the CR to about 10:1 (really really bad). So it won't work but the 12 degrees tilt is recommended with M150XN05 as well as using split fresnel with this LCD. Going to test it tomorrow. |
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| mhelin |
| I can see an improvement in contrast when tilting the panel. Unfortunately I also noticed that my condencer lens was broken and had to take it out (in three pieces), it was propably too close to the bulb and couldn't stand the heat. As a result the image isn't as bright as it was with the condencer. |
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| Henry Braithwai |
Hi!
First... I might be wrong on some aspects but I think this stuff I am going to say is at least worth thinking about...
I've been reading (and also participating sometimes) stuff on this forum for some years. There has been tons of discussions about the stuff that is behind the LCD, the problems and so on. I think that there is on fundamental error in the way the most people think about this stuff. We are wondering about point light sources and so on, but has anyone noticed that with about any kind of a reflector the light source has nothing to do with a "real" point? And how about the few people who have succesfully made projectors with fluorecent lights? What about the fact that you can project ANY bright image with a projection lens? Do you see where I am aiming here?
People... it does not matter if you have a point lightsource... all that matters is that the lcd should be as bright as possible. The method how that is achieved is not so important, the main thing is to have evenly lit as bright LCD as possible, because the brighter the real image that you are projecting is, the brighter will be the fake image on the wall after the projection lens. We are NOT projecting the lamp or anything behind the LCD, we are projecting the LCD, and that is how the optics should be thought also. Think about it... experiment and so on...
Regards
HB |
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| Henry Braithwai |
Just another point to support my view on this "pointsourceohitissohardtogetstuffbeforethelcdtowork"-subject:
My own projector project is based on a commercial projector (made by sony), and there is a glass/"lens" right after the lightsource, a similar glass to those that dentists have on their lighting, you know, those annoyingly bright thingies that they point at your face while drilling. Kind of a wavy glass with small squares... After that the light is hardly anything like a point source light or paraller or anything of that kind.
I think that in many setups on this forum the fresnell before the lcd does just the same thing, distributes the light evenly on the lcd. So, iI think that the whole setup before lcd is a very powerful backlight, nothing else.
Regards
HB |
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| Henry Braithwai |
I'll just keep going...
Do not think the LCD as an optical device, lens or some kind of a multicolored weird filter, as it is not. The LCD is the actual object that we are projecting, it is quite simple, there is a real object (LCD in the case of most here) on another side of the (projecting) lens, and a fake object (the image of the LCD) on the other, what is after or before this setup does not affect in the basic "operation" on this process of projection. If the real object is brighter, so is the fake object on the other side. If you know something about optics you should be understanding what I am saying... |
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| elstcb |
Using a point source and fresnel, or parallel light source just means more of the original light is useful, the higher efficiency of the system just means that lower wattage bulbs can be used. I agree it is possible to use flourescents, etc. and still get a good result, but more of the light will be wasted.
Lower efficiency = higher wattage bulb needed = more heat generated.
Steve |
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