ScottFHall
Newly Enlightened
Parabolic reflectors are ever popular, but my recent fiddling with fresnel lens technology in my The Pink Menace project sent me off on the tangent of: wondering a lot about aspects of carrying light over long distances with lenses alone. Yes, I'm considering both plano convex lenses, the Buffon lens, and Fresnels. Naturally, this caused me to do a lot of reading about lighthouses--wow, those old large scale fresnel set ups are just awesome!
Today I stumbled on something that I think relates: homemaking lamps using a tall stack of CD-ROMs.
I haven't built one of these yet but I'm pretty intrigued by it because--it seems to me--what you end up with is a full cylindrical lens that ought to throw light out fully around 360 degrees with some serious collimated intensity. I think a light like this, like a lighthouse beacon, would probably therefore be visible from very far away. Why? Well, I think the natural focal point of the transparent CD must be the dead center--the place where you'd put your 500 watt halogen cylinder bulb (or whatever). So, I gather that the photons emitted by the bulb are going to carry very uniformly and very efficiently through the disks. Hmm. I wonder. Surely, the big cylinder itself is going to glow with great intensity and yet, due to the opacity of material between CDs, lose brightness rapidly when seen from above or below angles.
I think one big variable for experimentation would be: how wide should one overbore the center hole of each CD? In other words, what's the optimum internal cavity? How will the edge thickness of the stack of CDs effect brightness and throw?
And of course, the type of bulb to be placed within a stack of CDs is a key point of experimentation. Long bulbs, like the halogen I mention above, ought to be just right for this. Of course, they are very hot so that would have to be dealt with carefully to avoid the danger of creating a vertical plastic Yule log of death.
Has anybody out there on the forum made one of these CD lamps yet? What did you find out in doing so?
Today I stumbled on something that I think relates: homemaking lamps using a tall stack of CD-ROMs.
I haven't built one of these yet but I'm pretty intrigued by it because--it seems to me--what you end up with is a full cylindrical lens that ought to throw light out fully around 360 degrees with some serious collimated intensity. I think a light like this, like a lighthouse beacon, would probably therefore be visible from very far away. Why? Well, I think the natural focal point of the transparent CD must be the dead center--the place where you'd put your 500 watt halogen cylinder bulb (or whatever). So, I gather that the photons emitted by the bulb are going to carry very uniformly and very efficiently through the disks. Hmm. I wonder. Surely, the big cylinder itself is going to glow with great intensity and yet, due to the opacity of material between CDs, lose brightness rapidly when seen from above or below angles.
I think one big variable for experimentation would be: how wide should one overbore the center hole of each CD? In other words, what's the optimum internal cavity? How will the edge thickness of the stack of CDs effect brightness and throw?
And of course, the type of bulb to be placed within a stack of CDs is a key point of experimentation. Long bulbs, like the halogen I mention above, ought to be just right for this. Of course, they are very hot so that would have to be dealt with carefully to avoid the danger of creating a vertical plastic Yule log of death.
Has anybody out there on the forum made one of these CD lamps yet? What did you find out in doing so?
