psone projector

[DIY BOB]

hi,
could anyone tell me the distance they have put there fresnel lenses from the psone lcd with the split option as i cant seem to get any picture and i think it is to do with the distance of the fresnels to the lcd as i have tryed every other option.

thanks

[mongals]

What type of fresnels do you have?

[DIY BOB]

hi monqals im not sure. i got them from ebay because i couldn't find them anywhere close to me. they are 4" by 6" and i cut them down to fit the size of the psone screen and they are 0.5mm thick plastic.

[jaycat]

easiest way i've found to figure out what the focal length is quite obvious:

get a VERY VERY small thing, like a pin, spec of dirt or something. Get a metric ruler. put the speck of dirt on a clean, plain surface. hold the fresnel parallel to the ground above the speck, approx 12 inches away. look down through the fresnel and find the speck. now move the fresnel slowly away from the speck, until the speck becomes HUGE on the fresnel. you should have the speck fill the size of the fresnel. hold it there, with your other hand, grab the ruler and measure the distance from the front of the fresnel to the ground. this distance is the focal length.

[DIY BOB]

thanks jaycat i will give that a try.

[alapimba]

if you bought it on ebay it's probably a page magnifier and not a real fresnel lens like the ones that everybody use.. "our" fresnel lens are about 3mm thickness... and don't bend so easily like your probably do.

Theres a few good sites to buy fresnels if you want. like lumenlab (in USA) or exclusive-online and izzotek (if you live in europe).

[DIY BOB]

hi guys,

im still having problems with my projector so i tryed replacing the lcd with a sheet of acetate with a picture about the size of the lcd and it worked but when i took the acetate out and replaced it with the lcd it dident work anymore.

does anybody know why???

i thought it was the light output from my 75w dicloric lamp so i changed it for a 150w flood lamp but still doesn't work. can anyone help.
would i be better with a 250w class A projector lamp with dicloric reflector. or not?

thanks

[sbisdabomb]

considering you loose about 90% of your light through the LCD you most likely need another light source. Those lights probabally aren't bright enough, have way to large of an arc gap, and are yellow due to thier low color temperature. You might want to look into one of the lower wattage metal halide light setups if you are looking for good results.

[jaycat]

or flip your lcd around so that the light is shining through the back of the LCD. i've read that lcd's are designed to have light through the back.
you'll have to add a mirror to flip the image back around of course (or use image flipping settings on your computer if using that for a source)

[HiLLBiLLY]

DIY BOB

Maybe a very silly question here but you have completely stripped the LCD haven't you?