I don't know if this would work or not, but I was kinda wonding about it, being that a small point light source is key. Make a seperate chamber in the back of the box for the light, reflector and a lens to condense the light to a point source at the point where the bulb would have been in the box in the first place. You could have your normal cooling fan drawing out to the chamber then fans in the new chamber a intake on the top and a exhaust on the back behind the reflector. Like the following sorry about the real crude paint job hehe.



I know this would make these boxes well even bigger then they already can be, but I was wondering if making the point source to a extremely small point would be a advantage, or would havng the light travel through yet another layer of optics cancel any possible gains. A secondary chamber for the light would make cooling easier too I would think.

Or would this work too, having the bulb at the very bottom of the box, underneath where it would normally go, with a lense above it aimed at a small mirror set at the new point source, angled towards the fresnel. I guess you would have to build a small wall infront of where the bulb sat too though, as you would not want the bulbs light directly hitting the panel as well causing a second point of light that was not at the right throw.

You cant make the point smaller than the original. We all like to dream of it but it doesnt happen.

You would have to be able to make the point smaller then the original or cooking a bug with the sun and a magnifying glass as a kid would not work. You are focusing the sun to a tiny point, and if that tiny point was able to run past its smallest point it would start to expand again would it not?

I read on a physics page the other day that you could make a point source of light by placing an apature of a specified size infront of the light(they did not give the size however) They also didn't say if or how much brilliance would be lost.

actually, you can make a smaller light point than the source with a lens.

I like to call it inverse projection. Is what happens inside the camera when you take a picture. The projected image is smaller than the original.

The problem here is that the lens needs to be far from the source so lot of light is lost. It does not worth it, but tecnically the idea of projecting smaller light source was right.

I have to disagree on a fine point. I interpreted the original question differently. Can you make the arc smaller and keep all the light? No! Can you make it smaller and lose a fair amount? Yes!

There is a physics issue called conservation of etendue. It is related to the second law of thermodynamics that states entropy (disorder) always increases.

You can make a point smaller than the original but you have to throw away light such that the total order in the system does not increase. In the case of the sun the light you get has almost perfect order. It has travelled 8 million miles and is almost perfectly parallel! Similarly for a picture. You take a bit of ordered light out of all the light coming from the object. That is why a small aperature has a greater depth of field! You can trade quantity of light for focus.

If you make a second point that is smaller than the original arc, you have converted some of the light to heat that is absorbed in the system. The increase in order of light is traded with an increase in disorder of faster moving molecules in the objects of the system.

Therefore the light is reduced. Having said that, if you are starting with a 30,000 lumen arc you can afford to lose some!

I do use an aperature at the focus of my reflector. I get a high quality of light after. Yes it is a good idea but its not free. My earlier post was really saying that I think i have reduced my etendue to close to the original out of the arc. Probably wishful thinking. Much is lost with all the bits of the system. I seriously doubt I have inproved (shrunk) the arc.

I greatly recommend your idea but be very careful thinking out how to make the most of the trade - lumens for quality of image.

The bottom line: If you could make the source smaller (increased order) without loss, you could then trade that improvement for heat and get it back to the original. Keep doing that and you have the perpetual motion machine - Infinite energy which is clearly impossible.