starting on this project: confused condenser lens and projection lens.

[csnv]

Hi guys, I'm new here and I'm so confused of how to calculate the size of the condenser lens and .. the factors in choosing a good object lens.

I'm learning a lot lately =).. as a newbie thinking of building a projector. I'm currently looking at the following:

-400w Ballast complete kit
-15" lcd
-norpro bowl as reflector
-a pair of condenser lens of some size (don't know the size)
-a pair of 15" Fresnel
-a triplet projection lense (don't know the specs for this either)
-cold mirror(i'm not sure what size either)

Here's the design i'm thinking of:

(bowl)_(light)_(condensers)_(fresnel)_(coldmirror)_(LCD)_(fresnel)_(projection)

Any thing would be helpful to me at this point. Thanks,
Tuan.

 

[Guy Grotke]

price some cold mirrors

A cold mirror big enough to use after the first fresnel would have to be as big as your LCD. I get the impression you will use a 15" panel, so that cold mirror will cost you thousands of dollars!

Looking at a Rolyn catalog, 100 mm by 100 mm cold mirrors are about $300 each. Figure out a way to use the surplushed $5 4.75" diameter cold mirror instead. You could get several and cut them into squares to tile together, if they were closer to the bulb.