Making an LCD Projector

Super Cameraman · Post by **Super Cameraman** » Tue Oct 03, 2006 12:38 pm

I was wondering, is it possible to make a projector out of an LCD screen? Like maybe use an overhead projector, and take the back off the screen so it's see-though, and put in on the projector? Would that work? I saw a website on how to make your own projector with an LCD screen, and I have one I'm not using...

-Super

atari2600a · Post by **atari2600a** » Tue Oct 03, 2006 12:52 pm

Yes, it's been done before, but I think you have to put it in a box.

Super Cameraman · Post by **Super Cameraman** » Tue Oct 03, 2006 1:01 pm

Okay, I sort of did it, but the screen isn't see-through enough... It looks like there's a dark film or something on the screen. Is there a way to get this off?

-Super

Website · Post by **Life of Brian** » Tue Oct 03, 2006 1:29 pm

Talk to hellraizer - he's done it before.

Kurt_ · Post by **Kurt_** » Tue Oct 03, 2006 2:45 pm

It was in popular science a while back. search in forum 42, there was a big topic on the subject, links to schematics and everything.

vskid · Post by **vskid** » Tue Oct 03, 2006 3:15 pm

Here is a topic about it a while back. I think the brightness of the light shines through the screen, like a backlight, but even brighter so it should shine through and to the wall (with the lens for focus of course).

joevennix · Post by **joevennix** » Tue Oct 03, 2006 3:50 pm

You have to add a fresnel lens to make the light form a square image on the screen. You can get these in the form of page magnifiers from Office Max. Then you just slap it in front of the screen, and put a triple lens system (from any old projector) on a sliding rail in front of it, and use the sliding rail to focus it.

And of course you need a light source at the very back of that, if you're using this only at night, you can probably go get a cheap, bright light. Usually you have to add a fan that blows air across the light and another one under the LCD to make sure the colors dont wash out. Then you enclose the whole thing in whatever material and BAM you have a projector.

vskid · Post by **vskid** » Tue Oct 03, 2006 3:58 pm

joevennix wrote:You have to add a fresnel lens to make the light form a square image on the screen. You can get these in the form of page magnifiers from Office Max. Then you just slap it in front of the screen, and put a triple lens system (from any old projector) on a sliding rail in front of it, and use the sliding rail to focus it.

And of course you need a light source at the very back of that, if you're using this only at night, you can probably go get a cheap, bright light. Usually you have to add a fan that blows air across the light and another one under the LCD to make sure the colors dont wash out. Then you enclose the whole thing in whatever material and BAM you have a projector.

I think his idea of using an overhead projector would be easier. This requires more thinking and exactness, with an overhead you just take the screen apart and put the LCD on the window thing.

usbcd36 · Post by **usbcd36** » Tue Oct 03, 2006 4:08 pm

Actually, doing that could overheat the LCD. Instead, use styrofoam to create a space between the top glass of the overhead and the LCD, then use a fan to push air through there. Here is one resource you might like to have as well.

If you want to make it even better, you could also replace the projector's bulb with one that has a cooler white point. You don't have to (calibrating the LCD to the yellowish light works too), but it might look better in the end.

Super Cameraman · Post by **Super Cameraman** » Wed Oct 04, 2006 3:19 pm

Well, what if I used an overhead projector? Just put the screen on it and it's done. But 2.5 inches is way small for a screen, right?

-Super

vskid · Post by **vskid** » Wed Oct 04, 2006 3:23 pm

Super Cameraman wrote:Well, what if I used an overhead projector? Just put the screen on it and it's done. But 2.5 inches is way small for a screen, right?

-Super

It would be a bit small. Like usbcd36 said, you need a bit of space between the glass and LCD for cooling.

Super Cameraman · Post by **Super Cameraman** » Thu Oct 05, 2006 12:49 pm

Okay, well I sort of did it. My school has an LCD projector in every single room, so last class I brought a CD of pictures and I was going to use my friend's laptop to show a presentation for a project, but the only broken LCD projector just had to be in that room. So today I brought in my digital camera with AV out cable, my Intec screen, with the LCD removed and disected, and I put it in that cool box that it came it. (Everyone was like, "What's in the box!?!?" And I was like, "A projection panel." "Um. Okay.) So I used my teacher's overhead projector and it worked great and everyone was amazed.

It got hot after a while, but I think it's okay.

-Super

hailrazer · Post by **hailrazer** » Sat Dec 16, 2006 6:36 am

Here's my projector. :
http://www.lumenlab.com/forums/index.ph ... opic=15796

I've also done one with a PSone screen. And I've done one with a slide projector and a 2.5" screen.

vskid · Post by **vskid** » Sat Dec 16, 2006 1:20 pm

A guy I know made a projector out of a rear projection TV. The mirror was busted and the people that owned it were throwing it away, so he got it from them for free. He took out the projection part, and has it hanging about 5 feet away from his wall. So he now has a 100+ inch HDTV that he got for free (lucky). So if you did that and got the right lenses and stuff, you might be able to have it up by the ceiling instead of in the middle of the room.