I'll have to take back what I said about my 500w worklight not being powerful enough. I did some more testing today (the diy ohp **** box without fresnel) and I could get the center of the image brighlty and clearly when all other lights in the room still on. All I really need now is properly working fresnel.
dwalls, can you give the url for your web page?
Anayet, brighter light makes better brightness, it doesn't affect in the picture clearity.
dwalls, can you give the url for your web page?
Anayet, brighter light makes better brightness, it doesn't affect in the picture clearity.
Sure, these are pictures of my first design and first prototype.
http://home.tampabay.rr.com/wwalls/lcd.htm
B**ch, what are you using for your LCD? I was getting the same center light problems as you, even with the brightest light I had with the large lcd I was using.
http://home.tampabay.rr.com/wwalls/lcd.htm
B**ch, what are you using for your LCD? I was getting the same center light problems as you, even with the brightest light I had with the large lcd I was using.
Hello bitch,
there's something you should know about optics. Every light that does'nt reach projection lens is lost light. The same, if light incidence angle is too steep to be refracted into projection screen.
The optimal light dispensation you get is when light source is a point light source, placed in the optical axis and nearest around. If light comes from outer regions the condensor (fresnel)lens will refract this light into other directions beside projection lens. A 500 w working light isn't a point-source light! Therefore a condensor doesn't make much sense. Look at different transmissive projectors, OHPs, slide... they don't have large sized lightbulbs. The size and focal lenght of condencer lens depends of the size of the projected object, in our case a LCD-Panel. What i've already said in another thread: The lighting system is a subsystem of projection. The lightsource is projected itself into the focal plane of projection lens. A working light has huge dimensions compared to lightbulbs. It's working like many small lightsources, but with less light output/area.
Remember, heat is going upwards. With 500 W working light you will have to cool powerfull. Without proper cooling you will cook fresnel lens and LCD. OHPs usually have an addidional IR filter on top of the lighting unit. Why not try with original OHP setup?
Greetings and Happy new Year to all!
xblocker
there's something you should know about optics. Every light that does'nt reach projection lens is lost light. The same, if light incidence angle is too steep to be refracted into projection screen.
The optimal light dispensation you get is when light source is a point light source, placed in the optical axis and nearest around. If light comes from outer regions the condensor (fresnel)lens will refract this light into other directions beside projection lens. A 500 w working light isn't a point-source light! Therefore a condensor doesn't make much sense. Look at different transmissive projectors, OHPs, slide... they don't have large sized lightbulbs. The size and focal lenght of condencer lens depends of the size of the projected object, in our case a LCD-Panel. What i've already said in another thread: The lighting system is a subsystem of projection. The lightsource is projected itself into the focal plane of projection lens. A working light has huge dimensions compared to lightbulbs. It's working like many small lightsources, but with less light output/area.
Remember, heat is going upwards. With 500 W working light you will have to cool powerfull. Without proper cooling you will cook fresnel lens and LCD. OHPs usually have an addidional IR filter on top of the lighting unit. Why not try with original OHP setup?
Greetings and Happy new Year to all!
xblocker
Okay, first I have to say that I have very hard time reading this stuff due to my not-so-good english skills so sentences like "The optimal light dispensation you get is when light source is a point light source, placed in the optical axis and nearest around." doesn't really say anything to me. So I'm sorry if I misunderstand something.
Anyway what I have right now is working overhead projector with non-properly-working fresnel lens so now I (again) ripped of the fresnel and played around with it in my "DIY projector" which actually is an one meter high plastic clothes(laundry) basket and in the bottom of it is the 500w worklight, and in the top of it lays right now my "non-working fresnel lens" from the ohp and then the LCD itself. And currently it's actually working!
I can get a good picture (light spreads evenly all around the image).
I'm trying to re-read and re-read your post xblocker but I just can't undestand what you are telling to me.
Anyway the thing is, the distance between my worklight and the LCD is one meter (because the manual says to keep the light at least one meter away from the ligting destination).
Without the fresnel, as I told before, I can see just the center part of the image. I could probably see the whole image if I attached the LCD straight next to the worklight but I think the LCD would melt.
But with the fresnel it's working fine now (Which is bit weird but I think the one meter distance from the light does it).
Now I have three problems left:
- Projector head mounting
- Housing
- Heat
Currently I'm keeping the projector head (the thing with the lens/mirror) in my hand while testing!! But I'm going to build some sort of stand for it.
But what would be proper housing?
I was amused by the dwalls projector's housing since I have been playing with cardboxes in here myself and thinking if I am sane at all, but apparently i'm not only one🙂 And now I have this laundrybox which is actually in a cardbox(!) to prevent the light coming out from the holes in the laundrybox.
But in what are you people planning to house your final product in?
The heat.. My tests now have not been longer than one minute long because I currently don't have cooling at all. The LCD has cooler of it's own but it won't probably take too long before the basket starts to melt and the cardbox sets on fire🙂 I haven't been thinking about the cooling too much, since I have no clue how I'm going to house the thing anyway. I have somewhere a normal "room cooler", thing which has a flect and then it spins around and blows air to the room, I don't know exact word for it in english but anyway I would just disable the spinning and place it in.. in... hmm. Okay, do I have to place the thing inside the laundrybox blowing through the holes, or can I put the cooler outside the box blowing cool air in to the box from the holes (which though probably isn't the standard protocol) but it would be easier to "mount" this way but does it not then work?
In the opposite side/wall to the "cooling" holes there are no holes in the same level but in the upper part there are few holes so I would think the air could escape from there but I have to say that I really don't know anything about anything so please help me!
Btw. nothing to do with the above stuff, I read that LCD panel (used with OHP) passes through 5% to 10% of the lumens of the OHP so if the OHP is 3000 lumens the output from the LCD is 150-300 lumens. I don't know how this applies to your LCDs/applications though..
Anyway what I have right now is working overhead projector with non-properly-working fresnel lens so now I (again) ripped of the fresnel and played around with it in my "DIY projector" which actually is an one meter high plastic clothes(laundry) basket and in the bottom of it is the 500w worklight, and in the top of it lays right now my "non-working fresnel lens" from the ohp and then the LCD itself. And currently it's actually working!
I can get a good picture (light spreads evenly all around the image).
I'm trying to re-read and re-read your post xblocker but I just can't undestand what you are telling to me.
Anyway the thing is, the distance between my worklight and the LCD is one meter (because the manual says to keep the light at least one meter away from the ligting destination).
Without the fresnel, as I told before, I can see just the center part of the image. I could probably see the whole image if I attached the LCD straight next to the worklight but I think the LCD would melt.
But with the fresnel it's working fine now (Which is bit weird but I think the one meter distance from the light does it).
Now I have three problems left:
- Projector head mounting
- Housing
- Heat
Currently I'm keeping the projector head (the thing with the lens/mirror) in my hand while testing!! But I'm going to build some sort of stand for it.
But what would be proper housing?
I was amused by the dwalls projector's housing since I have been playing with cardboxes in here myself and thinking if I am sane at all, but apparently i'm not only one🙂 And now I have this laundrybox which is actually in a cardbox(!) to prevent the light coming out from the holes in the laundrybox.
But in what are you people planning to house your final product in?
The heat.. My tests now have not been longer than one minute long because I currently don't have cooling at all. The LCD has cooler of it's own but it won't probably take too long before the basket starts to melt and the cardbox sets on fire🙂 I haven't been thinking about the cooling too much, since I have no clue how I'm going to house the thing anyway. I have somewhere a normal "room cooler", thing which has a flect and then it spins around and blows air to the room, I don't know exact word for it in english but anyway I would just disable the spinning and place it in.. in... hmm. Okay, do I have to place the thing inside the laundrybox blowing through the holes, or can I put the cooler outside the box blowing cool air in to the box from the holes (which though probably isn't the standard protocol) but it would be easier to "mount" this way but does it not then work?
In the opposite side/wall to the "cooling" holes there are no holes in the same level but in the upper part there are few holes so I would think the air could escape from there but I have to say that I really don't know anything about anything so please help me!
Btw. nothing to do with the above stuff, I read that LCD panel (used with OHP) passes through 5% to 10% of the lumens of the OHP so if the OHP is 3000 lumens the output from the LCD is 150-300 lumens. I don't know how this applies to your LCDs/applications though..
Hi Bitch,
sorry that you don't understand, my english is also not the best. I tried to use terms of physics, especially optics.
Now i try a little simpler: the optical axis is a line which goes from the center of a light source through the center of of all imaging components, lenses, lcd-panel, screen.
Point-lightsource means the light source is just a small light-emitting point. In reality, there doesn't exist such a perfect light source. Mostly light sources like bulbs lamps and even lasers have a size that isn't a small point.
Now we imagine, we had such a small point. Light is going into all directions, like the sun in cosmos, but as little point. You would agree that only a small part of light is going through LCD. The projection lens is still smaller than your LCD. Only the lightbeams which go through your projection lens will reach the screen. That's when you only see a bright circle and the edges are dark. It's called 'hot spot' effect.
So what's with the rest of the light? It's lost, if we do nothing! But there's a chance to regain some of the lost light. We can use a reflector behind the lamp or a so called condensor lens or both. They do no other job than collecting the lost light. But these light collectors work with optical rules.
case1 Reflector:
the lightpoint will beam as said on the optical axis to the screen. If we bring a mirror behind the lightpoint, we have 2 beams: one direct beam and one reflected beam. That means double brightness in the center of image. The rest of beam is now reflected but still in all directions exept behind the mirror. But what to do with the LCD border areas?
We have to move the mirror this way, that the lightpoint is reflected through the window border of LCD. This reflected beam should not only transmit the LCD but also go to projection lens to obtain a screenimage. You will notice that you must tilt the mirror slightly. If you instead of big mirror would take many little mirrors, then you would get a curved or spheric surface. This is called a spheric mirror.
Of course, not in all mirrorpositions you can reflect light through LCD a n d projectionlens. This light is really lost!
Case 2- Condensor lens:
A lens very simular as spheric mirror, but it's not reflective it's tranmissive. In case of lenses we talk of refraction. In both cases light is deflected from it's beam direction.
A condensor lens should always be between lightsource and object(LCD). It is only necessary for lightbeams which don't go into projection lens.
Each lens has a focus point. That means if parallel lightbeams go through they will be concentrated in this point called f. But we don't have parallel lightbeam here. So the distance between lightsource and lens has to be longer than f so that the beams can be concentrated again. It's easy to unterstand that beams who should go through borders of the LCD first have to go through the condensorlens and therefore the condensor lens must have the minimum the size of visible LCD. The f from condensor is important. It determins the distance from lightsource and the distance from LCD. If the distance between lightsource and condensor is too long, then the light will concentrate before projectionlens and diverge again(lost), if it's too short not all concentrated light will reach projectionlens.
Well, why should the light source be as small as can be? A large sized lightsource can be thought as many small lightpoints with the same specifications as talked about. Radiation in all directions. So if we consider the lightpoints away from optical axis we can say, all lightpoints in off-axis positions will reflected or refracted into areas where's neither LCD nor projection lens. Further, these many lightemitting points of a big lightbulb may have in summary great power but the lightpoints near the optical axis aren't as bright as should be.That's the point why projectionsystems should have small lightsources. If a lightbulb is p.e. 100 mm 500 Watts and another has 1 mm 500 watts then in the first case you have 5 Watt/mm. Isn't so good!
I hope thing are little more clear now. For me it's also hard to explain in foreign language. I think if building a projector there should be little knowledge of optics and projection systems.
Greetings
xblocker
sorry that you don't understand, my english is also not the best. I tried to use terms of physics, especially optics.
Now i try a little simpler: the optical axis is a line which goes from the center of a light source through the center of of all imaging components, lenses, lcd-panel, screen.
Point-lightsource means the light source is just a small light-emitting point. In reality, there doesn't exist such a perfect light source. Mostly light sources like bulbs lamps and even lasers have a size that isn't a small point.
Now we imagine, we had such a small point. Light is going into all directions, like the sun in cosmos, but as little point. You would agree that only a small part of light is going through LCD. The projection lens is still smaller than your LCD. Only the lightbeams which go through your projection lens will reach the screen. That's when you only see a bright circle and the edges are dark. It's called 'hot spot' effect.
So what's with the rest of the light? It's lost, if we do nothing! But there's a chance to regain some of the lost light. We can use a reflector behind the lamp or a so called condensor lens or both. They do no other job than collecting the lost light. But these light collectors work with optical rules.
case1 Reflector:
the lightpoint will beam as said on the optical axis to the screen. If we bring a mirror behind the lightpoint, we have 2 beams: one direct beam and one reflected beam. That means double brightness in the center of image. The rest of beam is now reflected but still in all directions exept behind the mirror. But what to do with the LCD border areas?
We have to move the mirror this way, that the lightpoint is reflected through the window border of LCD. This reflected beam should not only transmit the LCD but also go to projection lens to obtain a screenimage. You will notice that you must tilt the mirror slightly. If you instead of big mirror would take many little mirrors, then you would get a curved or spheric surface. This is called a spheric mirror.
Of course, not in all mirrorpositions you can reflect light through LCD a n d projectionlens. This light is really lost!
Case 2- Condensor lens:
A lens very simular as spheric mirror, but it's not reflective it's tranmissive. In case of lenses we talk of refraction. In both cases light is deflected from it's beam direction.
A condensor lens should always be between lightsource and object(LCD). It is only necessary for lightbeams which don't go into projection lens.
Each lens has a focus point. That means if parallel lightbeams go through they will be concentrated in this point called f. But we don't have parallel lightbeam here. So the distance between lightsource and lens has to be longer than f so that the beams can be concentrated again. It's easy to unterstand that beams who should go through borders of the LCD first have to go through the condensorlens and therefore the condensor lens must have the minimum the size of visible LCD. The f from condensor is important. It determins the distance from lightsource and the distance from LCD. If the distance between lightsource and condensor is too long, then the light will concentrate before projectionlens and diverge again(lost), if it's too short not all concentrated light will reach projectionlens.
Well, why should the light source be as small as can be? A large sized lightsource can be thought as many small lightpoints with the same specifications as talked about. Radiation in all directions. So if we consider the lightpoints away from optical axis we can say, all lightpoints in off-axis positions will reflected or refracted into areas where's neither LCD nor projection lens. Further, these many lightemitting points of a big lightbulb may have in summary great power but the lightpoints near the optical axis aren't as bright as should be.That's the point why projectionsystems should have small lightsources. If a lightbulb is p.e. 100 mm 500 Watts and another has 1 mm 500 watts then in the first case you have 5 Watt/mm. Isn't so good!
I hope thing are little more clear now. For me it's also hard to explain in foreign language. I think if building a projector there should be little knowledge of optics and projection systems.
Greetings
xblocker
Can someone recommend a LCD.
I've had a look at vdi_nenna site, and it has some top links, ands theres a wide selection to choose from.
Which one would be the best for this project (and also the cheapest😀)
Also, what is the difference between these LCDs being sold, and a ripped out old Laptop LCD?
I know these might be very basic questions to you lot, but i am just very interested in this a lot, and would like to learn🙂
Thanks
I've had a look at vdi_nenna site, and it has some top links, ands theres a wide selection to choose from.
Which one would be the best for this project (and also the cheapest😀)
Also, what is the difference between these LCDs being sold, and a ripped out old Laptop LCD?
I know these might be very basic questions to you lot, but i am just very interested in this a lot, and would like to learn🙂
Thanks
I am with Anayet. I would also like some suggestions on:
LCD sources
What types to use (mobile video, laptop, game system, etc.)
Pros and Cons of each
Resolutions
I know that most of this has been covered, but this thread is VERY long, some of the info is dated, and the "search" feature isn't very useful because of the thread length.
I've read through everything twice, and I'm hooked! As soon as I get a little more confident with finding the right parts, I'll begin work on this project. I'm short on funds, so I don't want to make any large mistakes early on.
Thanks for everyone's help!
-fender4
LCD sources
What types to use (mobile video, laptop, game system, etc.)
Pros and Cons of each
Resolutions
I know that most of this has been covered, but this thread is VERY long, some of the info is dated, and the "search" feature isn't very useful because of the thread length.
I've read through everything twice, and I'm hooked! As soon as I get a little more confident with finding the right parts, I'll begin work on this project. I'm short on funds, so I don't want to make any large mistakes early on.
Thanks for everyone's help!
-fender4
as like most of you i have been sitting in the background since this subject began, reading and waiting for some results.i wish not to offend anyone and i say this in the most scincere manner,but why not start out more simple.as i am comited to another more difficult project at this time i will be breaf.use a 4" lcd display with a crt projector lens such as a deltaII or deltaIV dirrectly in front of the lcd.as these lenses are made for a 5"crt placed in contact or close to it there is no need for trying to converge a large display such as a projector pannel for ohp.the only obsticle to figure out would be the light source.i understand most dont have large summs of money hanging around to purchase a premade system,if we did we wouldnt be here.granted a 4"lcd dosnt have the resolution of a ohp pannel but the end result will still be better than a 6,000$ unit you dont have now.think of this as a prototype with reusable parts.if you can get this working correctly than the lcd unit can be replaced with larger resolution pannel and a change to the lens assembly in the future as funds increase.again i ment no disrespect to anyone here,this is just my thoughts on the project
after i wrote my little 2 cents worth i decided to look back at other peoples ideas and found what zark was doing.his ideas are the same as mine and i dont want any misunderstanding that i stole his idea and am trying to pass it off as my own.i have entertained this project in my head for some time and decided to forgo this for a dlp project.i have had the main parts for it about a month and will try to get a site and some pix posted as funds allow.again im sorry if i offended anyone
Here's some interesting news in my email today! Texas Instruments is developing a DMD starter kit w/controller board. You can check out the details at http://www.prodsys.com/dmddiscovery/. As a side note, can anybody recommend a decent LCD panel from a laptop (specific models nos. would be nice) that have successfully been converted to a transmissive panel (similar to a overhead panel)?
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Great!?! And all this wonderfulness is available for the low, low price of $10,000 for the kit or $5000 for just the controller! Doh!! I think I'll stick to bodging mine together from scratch.
-------------------------------------------------------------------------
Great!?! And all this wonderfulness is available for the low, low price of $10,000 for the kit or $5000 for just the controller! Doh!! I think I'll stick to bodging mine together from scratch.
Why is two Lens (Fresnel + Projector Lens) required? Why do you need both?
Is the fresnel used to focus the light on the LCD or something?
And again, can a LCD Display from a Laptop be used for this?
Please help me with my questions
Thanks
Anayet
Is the fresnel used to focus the light on the LCD or something?
And again, can a LCD Display from a Laptop be used for this?
Please help me with my questions
An externally hosted image should be here but it was not working when we last tested it.
Thanks
Anayet
PTremb said:
Yes, Zark has figure most stuffs out already. He has also suggested a very affordable light source. I am very afraid to try, because if I build something that suck, the woman will dis me and say annoying things.
Also, I couldn't find crt projector lens on ebay now, nobody is posting them. I will try it out if I can find one cheap..
Also, where did Zark go? he is not w/ this thread anymore?
I also agree with Zark's approach for lighting...although I've never seen one in use, I know that the Lights of America 65w Fluorex light has been used with success in reef aquaria that require high-intensity, "white" light. If the intensity is adequate using these lights, cooling shouldn't present a large problem since these lights are very efficient.
As soon as I find a suitable LCD, I will try a setup with this type of lighting. Home Depot and WalMart sell these lights, I believe. They should be under $35 USD.
Good luck everybody. Let's keep this project alive!
-f4
As soon as I find a suitable LCD, I will try a setup with this type of lighting. Home Depot and WalMart sell these lights, I believe. They should be under $35 USD.
Good luck everybody. Let's keep this project alive!
-f4
how about using a lamp from a 35mm slide projector,granted they are only good for 70-80 hrs but at 10 bucks its not to hard to swallow,i think the one i had been thinking on using was a ekk model but dont hold me to it.this bulb has the parabolic reflector built into the envelope with the filliment and works on 30 or 40 volts.as far as the lens i think there is a guy thatwas selling 3 deltaII in the home projection section for 30$ if these are gone some of the 100" projector plans things sell the delta with a fresnel.if all gone just wait a day or two and they will be back, plus surplus shed sels them for 10$ http://www.surplusshed.com/list.cfm?Category=Lenses about half way down these are the 77 which are a slight bit smaller.as far as using a panel from a laptop this can be done,but with great expense because it dosnt have the driver seperate from the video card to drive the lcd pixels so this means having to try and puschase one or make one from scratch, personaly i would go with a premade unit with the drive unit built in and figure out how to seperate the board from the lcd as zark has done.anayet the reason for both the fresnel and the projector lens is the fresnel helps to distribute the light evenly to the entire surface of the lcd if the unit your using is larger than 4",and the projection lens makes the lcd image large on the wall. type-e dont let your lady dis you,get her involved for ideas or,just use reason and explain as things go that progress is happening,even if slow any improvement however small is in the greater good to knowlege ,if things dont go good dont get discouraged look at what happened and use it as an advantage to figure out why it happened that way.so when the project is finished however long it takes you can say "i did this" and be proud of your accomplishment.plus if it should break since you made it you can fix it, no going to high dollar shops
CRT Update
Right lads, I'm back again - been reading all the comments but not submitted any for a while, since I've been all over the country during the christmas/new year period. Hope you all had a good one.
I'm still considering testing a 3-CRT method, namely because there is no problem with accurate colour reproduction, no need for any cooling systems, and most importantly, I have three sets of US Precision lenses in my posession, although I'm unsure what code they are - watch this space - all I know is they fit a 5" crt face onto the lens.
As for this fantastic Fluerex (?) light, that sounds perfect for an LCD solution. I'm going to work on that too when I can find a supplier for this light in the UK. (Admittedly, I have not looked yet).
Does anyone know where I can get a 5" CRT in the UK? Black and white would be good. Any info on the fluerex light would be good too!
I'm going to build a mock system with my small pathetic 2" LCD screen in a couple of weeks, when I should also be in posession of a decent digital camera - watch this space for pics in the near future.
Cheers boys,
Chris.
Right lads, I'm back again - been reading all the comments but not submitted any for a while, since I've been all over the country during the christmas/new year period. Hope you all had a good one.
I'm still considering testing a 3-CRT method, namely because there is no problem with accurate colour reproduction, no need for any cooling systems, and most importantly, I have three sets of US Precision lenses in my posession, although I'm unsure what code they are - watch this space - all I know is they fit a 5" crt face onto the lens.
As for this fantastic Fluerex (?) light, that sounds perfect for an LCD solution. I'm going to work on that too when I can find a supplier for this light in the UK. (Admittedly, I have not looked yet).
Does anyone know where I can get a 5" CRT in the UK? Black and white would be good. Any info on the fluerex light would be good too!
I'm going to build a mock system with my small pathetic 2" LCD screen in a couple of weeks, when I should also be in posession of a decent digital camera - watch this space for pics in the near future.
Cheers boys,
Chris.
Does anyone know when http://www.whitelightled.com will reopen there site?
I have been trying to buy some things off there site a little after it was posted, and have been shown the same message about "reorganisation".
Does any one know when it will be open again, or somewhere else where i can get White LEDs at a low price like they sell - $1.50 each for 50+ ????
Thanks
I have been trying to buy some things off there site a little after it was posted, and have been shown the same message about "reorganisation".
Does any one know when it will be open again, or somewhere else where i can get White LEDs at a low price like they sell - $1.50 each for 50+ ????
Thanks
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