[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

I have download this program to my computer, that can calculate the measures we need for a given diameter/depth.

mscir.tripod.com/parabola/

This means I/we can give the exsact numbers for a given input (diameter/depth)to our manufacturer With this program the diagram it seem to be more efficient with a deeper reflector, because we gather more light rays in the beam, and we don`t get so much spill..

So I need to apologize a bit for my previous post about that 120/93mm measures, cause I just got that number (93mm) out of that given parabola in post #1789
I`m now more conviced that a deeper reflector is the way to go, but a deeper means also a lower measure at that (0.f) focus point. See pictures:









With that in matter I would go for a reflector that measures 120mm in depth as well, but that means a "real depth" of our reflector to be 120mm - 7,5mm up to the focus point = 112,5mm
In another term: that measure from an upscaled TN42 was correct! Hence my apologize... ;)

Yeah the focal length needs to be subtracted from the parabola height to get the actual height of the reflector.
That’s why the graphs I made completely ignore everything below the focal plane and you can adjust the actual height, the height you will get from the manufacturer.
Currently I have a function for intensity at an angle, a function for radius at an angle, and almost a function for total % light captured. Still working on it.

Got a picture of this? It might help to have a real world snap shot to give people an idea of the size.

I don’t think many people truly understand what kind of monster this will be.

Ahh!!
Looking forward to see your final work! :smiley:

BRING IT ON MAN!! :wink:

That’s cool, would you mind sharing that function? How did you interpolate the curve?

You mean a radiation diagram with the spherical surface integrated into it?
That would be helpful indeed.

I took the closest possible parabola to it, there is no easy way to make a function that copies the intensity curve unless you use piecewise, which I might try to do, or might not :stuck_out_tongue:
Anyway, it is pretty accurate. 0 to 100% intensity, –90 to +90 degrees.

Orange is the function, white is the intensity curve from cree.
Function is y=-.015x^2+100\left\y>0\right\
Green line at y=–1 indicates the degrees that are being collected by the reflector.

I’m interested in one.

Hoi fritz15,

I do not care about the banana, but I do love your design. :wink: :+1:

So, this will (eventually) show how much of the light from a given emitter would be collected and collimated from a given reflector size/shape?

The intensity curve should be very close to cos(theta). Because apparent area goes like cos(theta).

Yes! :smiley:

Enderman is doing an incredible job with this!! :+1:

Yes. See here for a bit of info on this.

This is what the pattern for total light contained at different angles looks like:

It is a polar graph of sin(x)cos(x). Grapher web app here.
It is sort of an unexpected result. Although the light coming right off the top of the LED is the most intense, there is more light at the steeper angles to the side, and this results in the “lobes” in the graph. This is why the light collection efficiency of most aspheric lights is bad and the light collection efficiency of most reflector lights is good.

That is very enlightening actually.

Thank you EasyB, that’s a very helpful visualization.
It’s almost incredible at first sight, itś hard to believe it’s based on that circle in the average radiation diagram.
It makes it seem miraculous how well an aspheric still throws.

Wow, just wow.
This isn’t anymore just a thread about a thrower, this is much more! Very awesome to see everyone putting their knowledge into this, never thought that we would really calculate and figuring out all that science about reflectors and stuff.

This is really why I love BLF and it’s members.

Indeed, it is nice to finally move past the cosmetics and get into actual productive work.

Yeah awesome
And it is very very cool to see that we have now calculated the reflector should be 112.5mm deep and not just blatantly upscaling the TN42 sizes. And highly impressive TN42 upscale is a tad “off” it seems so BLF has come up with better size then a pro company.

I don’t think there is anything special about any one particular diameter to depth ratio. As illustrated in Enderman’s pictures here , as the depth is increased the effective area increases, which increases throw, but after a certain point there stops being significant gain. The same can be said for the light collection efficiency; with roughly square dimensions the reflector is already collecting more than 75% of the light, and increasing the depth more results in only small improvements.

The reflector dimensions do affect the beam profile, so I think being able to simulate that would be helpful. Like DrJones did here:

Practically I think the 120x112mm size, or anything close to it, is fine and there won’t be significant changes to the beam unless the depth is changed drastically.

Without minimizing or diminishing anything you guys are doing, all of this is theoretical. Who is it that has the signature: “Theory sounds like a nice place, I’d like to go there one day, I hear everything works there.”?