I'm drawing a design for a reflector right now, I'll do it in photoshop and post it here. No lost of light at all. Don't know if had already this idea before, but who cares? 
The main idea is to do a bi-shaped reflector. Half is ellipsoidal and the other half is spherical, and put a condenser lens at the end.
I'll post it as soon I manage how to do a ellipse in photoshop, without filling it
The main idea is to do a bi-shaped reflector. Half is ellipsoidal and the other half is spherical, and put a condenser lens at the end.
I'll post it as soon I manage how to do a ellipse in photoshop, without filling it
Here it is
Blue lines and zones is light that will hit the ellipsoidal reflector and bounce directly in the condenser lens at focal point #2
Red lines and zones is light that will hit the spherical part of the reflector, going back to its origin, focal point #1, then bounce directly to focal point #2, the condenser lens.
An externally hosted image should be here but it was not working when we last tested it.
Blue lines and zones is light that will hit the ellipsoidal reflector and bounce directly in the condenser lens at focal point #2
Red lines and zones is light that will hit the spherical part of the reflector, going back to its origin, focal point #1, then bounce directly to focal point #2, the condenser lens.
Wow!
Great thinking Gui! Very creative use of combining reflector properties! I can't imagine why anyone hasn't used this before. Make sure you do a patent search on this thing to make sure noone's done this before, you might get a patent out of the deal.
I really like that idea. Way to be effecient!
Respectfully,
Clint
Great thinking Gui! Very creative use of combining reflector properties! I can't imagine why anyone hasn't used this before. Make sure you do a patent search on this thing to make sure noone's done this before, you might get a patent out of the deal.
I really like that idea. Way to be effecient!
Respectfully,
Clint
thanks! I was thinking of a way collecting all the light. The idea came out when I was trying to sleep
The only thing I don't like is that the bulb is kinda trapped in there, without air flow. Maybe I'll put some kind of heat sink on the outside of the reflector
For the patent, I'm sure it was already done before, but I'll take a look to be sure
The only thing I don't like is that the bulb is kinda trapped in there, without air flow. Maybe I'll put some kind of heat sink on the outside of the reflector
For the patent, I'm sure it was already done before, but I'll take a look to be sure
Air Flow
Yeah, that is a problem, getting the bulb to be mounted in there. Ideally you would have a spherical reflector and an egg-shaped ellipsoid with a magical point source of light at the focal point. What you *could* do is to blow air from around the base of the bulb, and have it come out around the condenser lens, just run air straight through it that way. I wonder if you could make this thing effecient enough to use a normal incandescent light bulb.
--Clint
Yeah, that is a problem, getting the bulb to be mounted in there. Ideally you would have a spherical reflector and an egg-shaped ellipsoid with a magical point source of light at the focal point.
What you *could* do is to blow air from around the base of the bulb, and have it come out around the condenser lens, just run air straight through it that way. I wonder if you could make this thing effecient enough to use a normal incandescent light bulb.--Clint
I've already think about a way to build one for the big cheap home depot mh bulb.
It's relatively easy. Trace the ellipse on a big piece of wood, with the focal point etc.. and trace the spherical part too. So this way you trace a real scale 2d reflector on the wood.
Then, with a router or a dremel, kinda grave the wood with it so you have a small encavure all the way on your reflector design. A gauge if you want.
Then you take some piece of alluminium, a long band of 1/4" or 1/2", place the alluminum in the gauge and follow the design so it will bend in the good shape. With that, you can build a frame of the reflector
As soon I can do it, I'll post pics of what I'm saying
It's relatively easy. Trace the ellipse on a big piece of wood, with the focal point etc.. and trace the spherical part too. So this way you trace a real scale 2d reflector on the wood.
Then, with a router or a dremel, kinda grave the wood with it so you have a small encavure all the way on your reflector design. A gauge if you want.
Then you take some piece of alluminium, a long band of 1/4" or 1/2", place the alluminum in the gauge and follow the design so it will bend in the good shape. With that, you can build a frame of the reflector
As soon I can do it, I'll post pics of what I'm saying
better off...
You'd be better off trying to come up with something for a smaller bulb. Those huge standard MH bulbs will NEVER do for lcd projection. They are just too big and not a good point source of light.
I have yet to see someone using one of them actually happy with the brightness... and they put out over 20,000 lumens! If your not happy with brightness at that level... you have the wrong bulb.
You'd be better off trying to come up with something for a smaller bulb. Those huge standard MH bulbs will NEVER do for lcd projection. They are just too big and not a good point source of light.
I have yet to see someone using one of them actually happy with the brightness... and they put out over 20,000 lumens! If your not happy with brightness at that level... you have the wrong bulb.
I think the real benefit of this reflector comes from using smaller, cooler bulbs to get as much effeciency from them as possible. Also, if you want alot of effeciency, you'll need to make this using not elipses and circles (think 2-d bent sheet aluminum), but 3-d with spheres and elipsoids.
--Clint
--Clint
I'm doing it "3d too "
the 2d on the wood is to build the frame. With somthing like 16 alluminium band, I'll do a 3d frame. ( I'll try to picture this )
And for the bulb.. I know it's big, but with this kind of reflector.. And its not a good point of ligth, well with a condenser.. its the lens the point of light, and with a very small focal point, you can place it very close to the fresnel.
I mean.. no lose of light or almost, so even if the bulb is big.
"the 2d on the wood is to build the frame. With somthing like 16 alluminium band, I'll do a 3d frame. ( I'll try to picture this )
And for the bulb.. I know it's big, but with this kind of reflector.. And its not a good point of ligth, well with a condenser.. its the lens the point of light, and with a very small focal point, you can place it very close to the fresnel.
I mean.. no lose of light or almost, so even if the bulb is big.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Hi,
I have similar ideas to share. Instead of using spherical and ellipsoidal reflector, I use normal spherical but extending it and become like sliced sphere. As we all know if we put light source at the center of spherical reflector, the light rays will reflected back to the center (fig. 2). Almost all of OHP using fig. 2 method. Size of the reflector is only a small portion of sphere, gap or space between reflector and fresnel panel is where the light spread and waste.
So my idea is covering the gap with spherical reflector too and it's what I called "extended spherical reflector".
How it's work? Here, when light rays leaving the lamp it will hit the extended reflector and bounch back but not in the center of spherical reflector, because the reflector shifted to the left a little bit, now there is a distance between center of reflector and lamp = X.
The effect is: light rays will bounch slightly to the left of reflector-center, it will bounch several time until it escapes from reflector and combine with direct light and reflected light from normal reflector, all light will hit the fresnel panel, no wasted light!
What do you think?
I have similar ideas to share. Instead of using spherical and ellipsoidal reflector, I use normal spherical but extending it and become like sliced sphere. As we all know if we put light source at the center of spherical reflector, the light rays will reflected back to the center (fig. 2). Almost all of OHP using fig. 2 method. Size of the reflector is only a small portion of sphere, gap or space between reflector and fresnel panel is where the light spread and waste.
So my idea is covering the gap with spherical reflector too and it's what I called "extended spherical reflector".
How it's work? Here, when light rays leaving the lamp it will hit the extended reflector and bounch back but not in the center of spherical reflector, because the reflector shifted to the left a little bit, now there is a distance between center of reflector and lamp = X.
The effect is: light rays will bounch slightly to the left of reflector-center, it will bounch several time until it escapes from reflector and combine with direct light and reflected light from normal reflector, all light will hit the fresnel panel, no wasted light!
What do you think?
Attachments
full scale size reflector design, based on those big MH bulb from home depot. 30 cm X 26,6 cm ... not to bad
An externally hosted image should be here but it was not working when we last tested it.
Here's an other full sized version, vertical setup.
An externally hosted image should be here but it was not working when we last tested it.
I'll try to do my reflector tomorow.
I'll do the technique I've show in this thread, but not with aluminium bands, but with what I'll call "metal rod or wire" since I don't know how you call it in english. In french it's call "broche a foin".
So with the wire, molded with the trace in the wood, I'll do a 3d frame of my reflector, and I'll use aluminium tape to finish it. I'll try to post pics if I can find a digital camera.
I'll do the technique I've show in this thread, but not with aluminium bands, but with what I'll call "metal rod or wire" since I don't know how you call it in english. In french it's call "broche a foin".
So with the wire, molded with the trace in the wood, I'll do a 3d frame of my reflector, and I'll use aluminium tape to finish it. I'll try to post pics if I can find a digital camera.
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