Maybe someone can clue me in on something. I've got a setup for a psone vertical design inside of a pc case. I've got 18" focal length on the field side but on the lamp side I had to double up the fresnels so that i could shorten the lamp/fresnel distance to 6 inches instead of the 12 it would be so that I can only have the one mirror. This puts the lcd 7 inches away from the lamp. I do have the lexan installed. But even with a box fan laying on top of the case after about 2 minutes my screen starts to burn in like you would see paper burning if you stuck a match under it. A slowly growing black circle. I really don't want to put another mirror in here. I know some other guys like Gra_pelayo have used ohp halogens before with really short focal lengths. How do you handle the heat? Should I use tempered glass instead of lexan? I need HELP!!

:angry: :angry:

Try the dichroic mirror out of this or maybe use the whole light engine. 50mm x 45mm x 2mm thick, and a DCX condenser lens

http://www.surplusshed.com/pages/item/m2407.html

Can you explain how the condenser lens falls into the picture? Could I go back with multiplied fresnels and move the lamp closer to the lcd again this way?

The condenser lens is just a lens placed close to the lamp so the it can collect light from closer to the lamp. I was thinking you could scrap the mirror from the unit. Or put your lamp in place of the one they used. The mirror will reduce the heat by 80%!! And give you a smaller box.
The ideal Fresnel for a 7" LCD might be 100mm or less. The light from a lamp spreads out fast the sooner you can get it to hit the first lens in a light system the better. The difference between 300mm and 150mm is more than double the light output. Small LCD will gain more from using a condenser than larger panels. Because of the size of the Fresnels.

So your theory is that I could put my lamp in this new light engine, and move it back under my lcd with the doubled up fresnels?

Arizona, thanks for your help but I'm getting all my questions answered in my second chance plog.

Thanks again!