BIG SCREEN TV Project - "Screen Material??"

[Whitedog]

Not sure if anyone has read the artical over at Toms about how to build your own XGA Projector, but you should check it out. Pretty cool artical.

ANYWAY, being I have a 15" TV/Monitor and got me a projector and did this myself, I have decided to take it a step further. Instead of having this projector in the middle of my den and shooting the video up on the wall, I am going to make my own 78" LCD Projection TV.

I made this REALLY CRAPPY concept drawing Click Here just to give you the idea.

The over-head projector is NOT going to be like what you see at Toms artical, it will be HIGHLY modified.

The big issue I have is getting some material to use for the SCREEN!

Does anyone have any idea what kind of material I could use? I need to find something that is at least 4' wide and 6' or more long.

The local hardware stores have plexiglass, but it is clear and only 3 feet wide. I don't think this will do. I need something "frosted" or something like that.

Any suggestions appreciated.

 

[SuperFreaky]

how about one of those pastic computer chair mats... What are real big screens made from? I remember it being like a plexi-glass with a pattern presses on it...

How are you going to deal with heat?
How long do you expect the LCD to last before it starts to fade?

 

[Matthias99]

Try a search over at www.avsforum.com. They have multiple forums dedicated to projectors, and I've seen threads there about where to get screen materials. If you're willing to build a frame yourself, you can get very high-quality screen material pretty cheap.

There's also flat white paint and a wall...

 

[Boogak]

Black out cloth at a fabric store works great.

 

[Whitedog]

Originally posted by: SuperFreaky
How are you going to deal with heat?

Well, as far as heat goes... as i said, I will highly modify the projector to use Florescent lighting instead of the "HOT" halogen lights they have in them. This will also extend the life of the lighting.

How long do you expect the LCD to last before it starts to fade?

What causes the LCD's to fade to begin with, is the light panel itself.

The standard halogen projector lights (400 watts) have a lifepan of only 150 hours and put out around 3500 lumens and "AS YOU GUESSED" HOT.

I can achieve about 3500 lumens with 50 watts of florescent lighting with a lifespan of about 10,000 hours. So heat isn't going to be any problem.
You know LCD flat panel monitors use florescent lighting don't you?

Anyway, I came back to say I found some "material" at the "e" place where you buy stuff. A company called Dazian sells ALL kinds of projection screens and materials. A 86 x 72 piece is going to run about $ 110. That's not too bad. They have sized up to 110 x 180 for rear projection! Wow!

I think I will try a piece of this material and see how it goes. I will report back with Pics of the whole project when I am finished.

They ALSO have this "paint" or something you can coat plexiglass with to use as your screen, which would probably be "better", but the paint is "expensive" as hell ($337.00 for a half gallon).

GET BUSY WITH YOUR OWN PROJECTION PROJECT!

 

[Caveman]

Everything you could ever want to know about DIY Screens is here:

http://www.avsforum.com/avs-vb...php?s=&forumid=110

 

[Dug]

Two problems.
#1) regular screen material will not work in your proposed setup. You need a semi-transparent screen material.

#2) It will look like crap because you will loose so much contrast doing this.

#3) Changing bulb will change all color you are used to.

#4) By the time you buy the screen material (it is available) it won't be cost effective. Meaning you could go out and buy a real projector and save the money by using blackout cloth and have 2x better image + tiny projector + better resolution + more connection options.

 

[MichaelD]

I built my HT screen (44" x 78") from Blackout Cloth. BO cloth is what's used to make light-blocking drapes. It's semi-elastic. You build a frame out of wood or aluminum and stretch/staple the cloth over it, pulling tight as you go.

This thread at AVS is concerned THE thread on the subject.

I post there under the same name; I asked tons of questions, got answers and built my onw. I believe I have pics in there as well.

Here's a pic for you.

Pic of my screen

It's a frame within a frame. The inner/white part is 1x3 pine boards glued/nailed together. The outer frame is the same pine board setup, sized to fit perfectly around the inner frame. Black felt is stapled around the boards. The inner and outer frames are held together with mending plates (flat pieces of metal w/holes in it for screws).

Hope this helps.

*edit*
But Dug does have a point...you won't be using this screen in a "traditional manner." So I'm not sure WHAT you need. IMHO, that whole article (I read it) at Tom's is a bit..."out there." The LCD monitor would get SO hot sitting on the overhead projector...I wouldn't do it.

 

[AWhackWhiteBoy]

halogen lights have an excellent color spectrum, changing it to florescent would hurt this big time

 

[AWhackWhiteBoy]

By the way, I already have an LCD to make one of these, its been sitting at home for some time. Where did you get your overhead, i'm trying to find one cheap, I already scored an LCD for under $50, i'd like to try and keep my costs under $100 minus the fabric for the image.

Where is a good place to look for overhead projectors aside from e-bay and local schools?

 

[NautikaL 8]

that projector will suck so bad. it will put out little brightness and contrast, and just be horrible. even though u get a bright bulb, most of the light leaks out and wont be projected onto the screen

you should head over to AVS forum if you want a projector

 

[Whitedog]

I got my over-head at the "e" store. $22 + $20 shipping. Total $42. That was a bottom dollar deal. Most are going for more.

In response to:

halogen lights have an excellent color spectrum, changing it to florescent would hurt this big time

The backlighting unit inside LCD panels are florescent. I don't see how it is going to hurt it much. I will have to just try and see. I am trying very hard to get away from the 400 watt bulbs those things use. They get VERY hot and have an extremely short lifespan.

Currently my setup is still just sitting on the unmodified projector. I'll have to experiment with the lighting.

Two problems.
#1) regular screen material will not work in your proposed setup. You need a semi-transparent screen material.

#2) It will look like crap because you will loose so much contrast doing this.

#3) Changing bulb will change all color you are used to.

#4) By the time you buy the screen material (it is available) it won't be cost effective. Meaning you could go out and buy a real projector and save the money by using blackout cloth and have 2x better image + tiny projector + better resolution + more connection options.

Well, that's actually 4, not 2.

1) I am not going to use "regular" screen material. They make "Rear Projection Screen" material. It cost about 4x what the other does, but it's made especially for "rear projection".
2) No it wont. It will look exactly like what you see in the stores with those Projection LCD TV's. Good picture IMO. Actually will be better. I will have 1024x768 resolution.
3) This could be true. I'll have to experiment. Also, I'd like to find out what kind of light they use in the store bought LCD projection TV's. Anyone have any idea? Surely not halogen?
4) The material I plan to buy will cost me $110 for a peice 86x72. This will allow me to make a screen size of 6 feet wide by 4.5 feet tall for a diagonal picture size of, get this... 90"! (That's a big TV)
The whole project is going to be under $500 when I am finished.

Thanks for the link Caveman.

And you too Matthias99.