Hi guys,
I think I'm going to bite the bullet and get a Dell 1503FP monitor to replace my nview panel. That being the case, my OHP will be too small to catch the ends of the screen. No biggie for movies, but for gaming, those edges could be a problem...😉
I thought I saw someone with a solution for this...I think they bought a new, larger fresnel and glass, but I'm not sure how they implemented it.
Anyone have any ideas?
Thanks!
I think I'm going to bite the bullet and get a Dell 1503FP monitor to replace my nview panel. That being the case, my OHP will be too small to catch the ends of the screen. No biggie for movies, but for gaming, those edges could be a problem...😉
I thought I saw someone with a solution for this...I think they bought a new, larger fresnel and glass, but I'm not sure how they implemented it.
Anyone have any ideas?
Thanks!
I"m by no means an expert, but i can tell you this.
Skip this poart if you are pretty well read on fresnel lenses.
First off, the top of your OHP (overhead Projector) where transparencies are placed, is actually a fresnel lens. Actually its probably two of them.
Every Fresnel lense has a property called "Focal Length" this is pretty much the distance from the fresnel lens that all the light gets redirected. Thus if you were to place your hand there, and a light were on the other side of the fresnel, then you get the little hot dot that so many of us used to burn ants when children.
This is usually represented with a millimeter measure. So here is the deal.
If you have a new LCD thats too large for the (this is kinda tricky, but i'll tell you every name it has, and they are all the same thing) Stage/aperture/stage aperture/fresnel/top-of-the-projector........ If your new LCD hangs over where there is no glass, and you can't see the edges, then you simply need to get a fresnel lense that is atleast as big as the screen you want to use.
But there is more. Remember back to the focal length. Youll need to get a fresnel with exactly the same focal length as the existing one. If you dont know what the focal length is.... then take the existing one out, and hold it out infront of a wall opposite of a window, er between a wall and a window, or some other light source, and move it away or towards the wall untill you get the sharpest light on the wall. Then measure that distance, and thats the focal length. Kinda tricky, but it will work.
Here is another thing to rememeber. If you simply want to replace it with another one, then youll have to rig the top of your old OHP to hold the new Fresnel at the proper height. Its gonna take a little bit of thinking, and adjusting, but you can get it.
One last thing. About fresnels:
You can buy them at www.3dlens.com
P.S. Just so you know, the smalled the "groove pitch" (this simple means the distance between the grooves in a fresnel lens) the better it is. Thus a .5mm pitch is not as clear as a .2mm pitch.
For anyone else reading this, correct me if i'm wrong.
Skip this poart if you are pretty well read on fresnel lenses.
First off, the top of your OHP (overhead Projector) where transparencies are placed, is actually a fresnel lens. Actually its probably two of them.
Every Fresnel lense has a property called "Focal Length" this is pretty much the distance from the fresnel lens that all the light gets redirected. Thus if you were to place your hand there, and a light were on the other side of the fresnel, then you get the little hot dot that so many of us used to burn ants when children.
This is usually represented with a millimeter measure. So here is the deal.
If you have a new LCD thats too large for the (this is kinda tricky, but i'll tell you every name it has, and they are all the same thing) Stage/aperture/stage aperture/fresnel/top-of-the-projector........ If your new LCD hangs over where there is no glass, and you can't see the edges, then you simply need to get a fresnel lense that is atleast as big as the screen you want to use.
But there is more. Remember back to the focal length. Youll need to get a fresnel with exactly the same focal length as the existing one. If you dont know what the focal length is.... then take the existing one out, and hold it out infront of a wall opposite of a window, er between a wall and a window, or some other light source, and move it away or towards the wall untill you get the sharpest light on the wall. Then measure that distance, and thats the focal length. Kinda tricky, but it will work.
Here is another thing to rememeber. If you simply want to replace it with another one, then youll have to rig the top of your old OHP to hold the new Fresnel at the proper height. Its gonna take a little bit of thinking, and adjusting, but you can get it.
One last thing. About fresnels:
You can buy them at www.3dlens.com
P.S. Just so you know, the smalled the "groove pitch" (this simple means the distance between the grooves in a fresnel lens) the better it is. Thus a .5mm pitch is not as clear as a .2mm pitch.
For anyone else reading this, correct me if i'm wrong.
kb18951452 said:
This is not true in our application.
We are using the fresnels to manage the light and not as resolving lens. We use the triplet as a resolving lens, that's why there is a space betwen the fresnel and the Lcd. We are focusing on the Lcd not the fresnel.
So using a tighter groove pitch in the projector would decrease the light output because more lines would make more interesections which would equal less light. So while it might seem "clearer" you would lose a lot of light which would negate that effect.
There is one thing i am not sure on, still, and that is a little better esplination of number of lenses, and why few or many is better, or what the perks are, som people design PJs with two frewnells and condenser, and a focal lens (i am assuming i am using the correct terms, condenser is nearly against the light to help make more light hit the fresnell evenly?)
But then there are others who have a light, a fresnell, and then a focal lens, just a single, not a triple. What are the trade offs? obviously the more lenses you have, or layers, the more light that gets blocked. But if im more or less just going for works, and focuses pretty clear, thats not all that hard is it.
I'm just rambling. Sorry. I simply am confused about how to pair lenses.
It is my understanding that lenses have focal points, well...... do they all have to match? or just the ones right beside one another?
Secondly, and hopefully lastly, that is, what if i want to be farther back? What is i have allot of room to move back? What kind of changes are needed for a longer throw length? and what changes are needed for a shorter throw length?
But then there are others who have a light, a fresnell, and then a focal lens, just a single, not a triple. What are the trade offs? obviously the more lenses you have, or layers, the more light that gets blocked. But if im more or less just going for works, and focuses pretty clear, thats not all that hard is it.
I'm just rambling. Sorry. I simply am confused about how to pair lenses.
It is my understanding that lenses have focal points, well...... do they all have to match? or just the ones right beside one another?
Secondly, and hopefully lastly, that is, what if i want to be farther back? What is i have allot of room to move back? What kind of changes are needed for a longer throw length? and what changes are needed for a shorter throw length?
Thanks for the response guys. Yah, I realize I need to get a bigger fresnel, but I'm not sure how to go about doing it(besides buying it). I'm thinking if I just take off the whole cover of the OHP and lay the fresnel and glass on top, that is the biggest it'll get...I'm just wondering if anyone else who was successful did it another way....
Also, if I just take off the top piece, the fresnel and glass will now be closer to the bulb and subsequently farther from the triplet lens...not sure if that would make a difference...I figure it would be a difference of about a 1.5" or so...
Thanks again for responding!
Also, if I just take off the top piece, the fresnel and glass will now be closer to the bulb and subsequently farther from the triplet lens...not sure if that would make a difference...I figure it would be a difference of about a 1.5" or so...
Thanks again for responding!
You can also make your image smaller.
While it is not perfect solution you can use your LCD until you
find permanent solution.
Here is utility that works pretty good.
http://www.dogbitesbowl.50megs.com/
it is called picasize.
Cheers!
While it is not perfect solution you can use your LCD until you
find permanent solution.
Here is utility that works pretty good.
http://www.dogbitesbowl.50megs.com/
it is called picasize.
Cheers!
The picasize is probably similar to powerstrip(or something like that). The problem is that I'm playing DVDs and games away from a computer...so that rules out that...If I got a video card that could take video input, would your program work?
Then I could just hook everything into there...*shrug*
Then I could just hook everything into there...*shrug*
You front (field) and back fresnel lenses are essentially independent of each other. The back fresnel's focal length determines how far back you want to put your light bulb. The field fresnel determines how far you put your projection lens. There are calculation for all of this of course. Random numbers won't work well. Check the theory page at DIYprojectorcompany.com. Also, the equation:
1 / (Projection Lens Focal Length) = 1 / (Distance from LCD to projection Lens) + 1 / (Throw)
This will help you figure out which field fresnel lens to get and where to place your LCD (the LCD is NOT placed at the projection lens' focal length every time).
About the OHP... Take out the old fresnel. Find the focal length of the fresnel lens. Get a new fresnel that has a FL close to the old fresnel. Use a dremel or a metal cutting tool to cut away a new hole (for the new fresnel to fit into). Replace everything. 🙂 Good luck!
1 / (Projection Lens Focal Length) = 1 / (Distance from LCD to projection Lens) + 1 / (Throw)
This will help you figure out which field fresnel lens to get and where to place your LCD (the LCD is NOT placed at the projection lens' focal length every time).
About the OHP... Take out the old fresnel. Find the focal length of the fresnel lens. Get a new fresnel that has a FL close to the old fresnel. Use a dremel or a metal cutting tool to cut away a new hole (for the new fresnel to fit into). Replace everything. 🙂 Good luck!
Ok here we go again.
First, When you move the fresnell down, it is going to change a few things. You could, as he has previously show, pick a new shape for the whole thing, and make a pretty good looking box for the whole things, and move the fresnell just where you want it.
Secondly, I know there are about a million of these, and hopefully someone will be able to sugest the best. Sure wish there was a polling system in these forums, maybe there is, for important things like:
Which "any-video-type" to VGA converter was the most used, and best. There are many. They go from anywhere between as little as $50 USD to $100 USD. I saw one just the other day. Lemme go look.
In the mean time, lemme tell you this. There are those that have RCA, VGA, and S-Video IN. Personally, i would like one that includes a TV Tuner also. This means it needs to have Coaxial IN
One last thing. You really going to want to change the bulb, atleast, because the average life of an OHP bulb is about 50 hours. A Metal Halid bulb........ well, if it goes out before 10,000 hours, it was probably a lemon, but the life is between 10 and 20 thousand hours.
No i didnt get those numbers mixed up, and no they arn't fake.
Secondly, These bulbs are between 10 and 30 thousand lumens, and no didn't get these numbers messed up either.
(i hope now your thinking to yourself "Man i really should just put a little more time in this, and make my own box design."
Sorry, Someone hopefully will tell us of they're experiences with * to VGA converters.
First, When you move the fresnell down, it is going to change a few things. You could, as he has previously show, pick a new shape for the whole thing, and make a pretty good looking box for the whole things, and move the fresnell just where you want it.
Secondly, I know there are about a million of these, and hopefully someone will be able to sugest the best. Sure wish there was a polling system in these forums, maybe there is, for important things like:
Which "any-video-type" to VGA converter was the most used, and best. There are many. They go from anywhere between as little as $50 USD to $100 USD. I saw one just the other day. Lemme go look.
In the mean time, lemme tell you this. There are those that have RCA, VGA, and S-Video IN. Personally, i would like one that includes a TV Tuner also. This means it needs to have Coaxial IN
One last thing. You really going to want to change the bulb, atleast, because the average life of an OHP bulb is about 50 hours. A Metal Halid bulb........ well, if it goes out before 10,000 hours, it was probably a lemon, but the life is between 10 and 20 thousand hours.
No i didnt get those numbers mixed up, and no they arn't fake.
Secondly, These bulbs are between 10 and 30 thousand lumens, and no didn't get these numbers messed up either.
(i hope now your thinking to yourself "Man i really should just put a little more time in this, and make my own box design."
Sorry, Someone hopefully will tell us of they're experiences with * to VGA converters.
Well, I already do have a metal hylide bulb running in my OHP...yah, I love the hours to cost ratio...I also do have a VGA converter, it's the Viewsonic one...however, the viewsonic does not allow me to modify the size of the image...just change resolution, color, etc...
So, what I was saying was that I'd have to find a pc video card that can take video input and then pump it out to my viewsonic or straight to my lcd screen...
So, what I was saying was that I'd have to find a pc video card that can take video input and then pump it out to my viewsonic or straight to my lcd screen...
Why would you not want to use the entire LCD?
Maybe because you don't want to get another fresnell? Ok i think i got it.
Youde rather send a smaller image to the LCD to you can simply use the projector that you have.
Now for that i have no idea.
But the fresnells aren't all that much.
And with a few changes you wouldn't have that hard of a time.
Maybe because you don't want to get another fresnell? Ok i think i got it.
Youde rather send a smaller image to the LCD to you can simply use the projector that you have.
Now for that i have no idea.
But the fresnells aren't all that much.
And with a few changes you wouldn't have that hard of a time.
yah, you got it...I pretty much have 3 options...
1) enlarge the fresnel(somehow-prolly mangle OHP) so at 15" stripped monitor fits completely
2) Use computer software to shrink the image on the stripped monitor(but then how do I play xbox n stuff on it?)
3) Just suck it up and lose the edges on the lcd...I don't mind for movies too much, but for games, it would make a huge difference...
1) enlarge the fresnel(somehow-prolly mangle OHP) so at 15" stripped monitor fits completely
2) Use computer software to shrink the image on the stripped monitor(but then how do I play xbox n stuff on it?)
3) Just suck it up and lose the edges on the lcd...I don't mind for movies too much, but for games, it would make a huge difference...
well, just so you know, its not going to be all that hard to change things in the OHP. You simply need to make room for the new fresnell lens. Figure out what sife you need, and get a larger diameter one that matches the focal length.
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