Future development of the maximum luminance of LEDs

wait, so luminus intensity doesn’t depend on reflector shape?, so what if i have a very deep reflector( like 2cm diameter OTF) and 20cm OTF but narrow, both have same area, they will throw the same, right ?

No, it doesn’t. That’s a very common misconception.

If you have two reflectors with the same outer diameter but one is deeper, the deeper one will have a slightly smaller led opening. This increases the total reflective area slightly. The larger the reflector, the less important this becomes.

Deeper reflector = smaller hotspot and more corona.
Shallower reflector = bigger hotspot and less corona.

At constant diameter? Deeper reflector = larger hotspot……
Same intensity * more lm collected by the reflector = larger spot

Saying same thing in other terms…
All parabolas are the same except for the scale. All parabolic reflectors are (geometrically) the same except for the scale and 2 cut points.
Scale is usually expressed in terms of focal length (FL).
For a given emitter beam angle depends on FL and on nothing else. Larger FL = narrower beam.
For constant diameter, larger FL = smaller depth. So less deep = smaller spot.

You need to differentiate between hotspot and corona (“coma”). Deep reflectors (at the same outside diameter and same size LED) make the actual hotspot with maximum intensity smaller and the corona surrounding it bigger. The corona also has a high intensity, much higher than the spill, but noticeably lower than the hotspot itself. This fills in the dark gap between the hotspot and the spill when shining the light into the distance. This can create a more practical beam.

Armytek uses very deep reflectors. You can compare beamshots of them with those of lights from other manufacturers.

I can’t stand the armytek hotspot within a hotspot effect from their deep reflectors myself.

Same goes for, for instance, the Thrunite TN31.
Deep reflector, small hotspot, large corona.
Take out the XM-L2 and replace with a (decomed) XP G2 and you get an even smaller hotspot and an even bigger corona

The large corona makes these intense hotspot throwers more usable because you can still illuminate something next to the hotspot.

Example of a thrower with shallower reflector and thus larger hotspot (but almost no corona): Olight M2X Javelot and Amutorch JM07.

No one can accuse me of having in dept knowledge of the physics behind it all; i draw my knowledge from field experience.
And I like to read a lot about things I like :wink:

Cheers,
Nico

I also like that shallow reflectors have a wider spill beam, making for slightly better illumination of immediate surroundings. I value that quite a bit as well.

Thank you for the helpful post.

The Osram Black Flat HWQP might be a bit better now .

Thanks for this, really gives some food for thought. :slight_smile:

Difference between 100mm and 120mm depth with 120mm width (iirc)

With a shallower reflector, the focal distances are always larger, thus more throw.
Yeah you have a little more / wider spill, but i don’t think that makes too much of a difference for the throw.

Here you can see how little more depth adds:

What are you trying to show us with your pictures?

Basically that a less deep reflector is better for throw, when the diameter is fixed.
Focal distances are longer with less deep reflector, because it’s a larger parabola than a deep one.
Added depth doesn’t add much light hitting the reflector.
Your drawing is a bit misleading i.m.h.o. because it ignores the radiation pattern of the LED.

Enderman’s calculators claim otherwise.

All domeless LEDs have generally the same radation pattern. They are basically lambertion emitters.

The depth of a reflector for a given diameter has no noticeable effect on throw. It just changes the proportions of the different parts of the beam. It’s simple math.

You have made these statements multiple times, but your diagrams don’t prove them. They don’t show anything pertaining to luminous intensity (throw) except for the diameter of the reflector.

The focal length of reflectors does not effect throw.

I included the radiation diagram (the 2 lobes), and most of the light is emitted at 45° angle, or at least, so i’m told by various members.
It makes sense, because even though the forward bit is brightest, this is just in 1 direction (forward), whereas at 45° it shines around. That’s why the lobes are 100% or factor 1 at 45°
I do have some doubts about this though, since i found an aspheric with the same diameter should catch less light but throws further none the less (Tested SupwildFire reflector compared to B158 lens)

Yeah, i expected we would disagree again on this… :slight_smile:
But with every collimating optic the focal length matters regarding the size of the projection.
The question is:
do you want to decrease the focal length in exchange for a few more lumens hitting the reflector?
Look how every bit of increased depth adds less and less degrees of collimated light.
Not only that, but the combined intensity of this rim of light weakens accordingly.
Is it worth it?
I doubt it.
Unless the lobed radiation diagram is incorrect, which could be the case…

The radiation diagram with the lobes is correct, and so as you make the reflector deeper and deeper the gains in light collection become less. But the interpretation that the light is “weaker” at these angles is not correct. When it comes to throw it’s the luminance (and frontal area) that matters, and the luminance is the same from all angles.

It’s not weaker, but there’s less of it, otherwise you wouldn’t have those lobes, right?
It’s quite hard to put it into words… :person_facepalming:
But still, experimenting with a B158 lens on a SupWildFire suggest the lobes misrepresent reality…
So i don’t know.
But what strikes me every time this is discussed, is that the focal distances around that “magical” 45° is not taken into account.
In my experience a not so deep reflector makes a better thrower, because it’s a larger parabola size.
But obviously a very very short reflector will simply catch much less light to collimate.
I think the best proportions are between 3:4 and 1:1 (width : depth).