hi everyone!

i'm trying to build rear projector for a stand to be placed in a shop

the idea is to look like this (my mspaint skills SUCKS!)




my problem is that i have no idea how to calculate the mirror.
does anyone knows how to calculate this? or any clue to help me?
thanks!

Using the focal calc program, find the distance from the projector to the screen. Or if it’s a commercial projector there should be some ratios in the manual. Draw a scaled diagram showing a triangle where the light path is. Now add a mirror in the path where you would like the fold. Simply fold the path where the mirror intersects the peripheral rays.
Here are a couple of examples:

Click to view attachment

DJ