Full Version: What size FS Mirror for 17 inch lcd and 360 triplet
I need some help in determining what size my FS mirror should be in a horizontal folded design. I will be using a 17 inch lcd, 220/330 unsplit fresnel behind lcd and a 360mm FL objective projection lens. Was thinking of placing the center of the mirror at 180mm from the lcd.
The standard ll mirror will be ok,I have heard they can be cut like regular glass,although I havn't tried it myself!! 
If you want to,draw a line as wide as the fresnel,then draw a line from the centre of that line perpendicular to it and mark the distance on that line the same distance away as the focal length of the fresnel.now join from the edges of the first line,that represents the fresnel,to the point on the second,perpendicular line you drew.
You should now have a long triangle shape.
Then you will be able to intersect that line with a sheet of card/paper,that represents the mirror,and see where you want to place it,and judge how big you will need it to be.
Cheers P
If you want to,draw a line as wide as the fresnel,then draw a line from the centre of that line perpendicular to it and mark the distance on that line the same distance away as the focal length of the fresnel.now join from the edges of the first line,that represents the fresnel,to the point on the second,perpendicular line you drew.
You should now have a long triangle shape.
Then you will be able to intersect that line with a sheet of card/paper,that represents the mirror,and see where you want to place it,and judge how big you will need it to be.
Cheers P
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