BLF recoil über-thrower

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Enderman
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Hey @The_Driver, could you look this over and confirm or deny for me?
——————————————————————————————————————————————
If the center spot intensity depends on the front area, then these two parabolic reflectors would have the same intensity:

(ignore the uneven distribution of the rays)
Both are 120mm diameter, but one collects 180 degrees (100%) of light, while the other collects 60 degrees (25%) of light.
.
.
So we take the second reflector, and make a lens with an equivalent focal distance and diameter:

Now both the lens and reflector collect the same cone of light, both 25%, and create the same size spot because the surface of both optics is at the same distance from the LED.
Assuming nothing is blocking the reflector, they should have almost identical peak intensity.
.
.
Then, taking into consideration that a wavien collar would increase the intensity by 2.3x, there is no center circle blocking light, there are no “beams” that would hold the center LED in place, and it is easier to provide cooling to an LED behind a lens rather than on a long heatpipe in front of the reflector, I would assume that the peak intensity with the lens would be close to 3x that of the reflector.
.
.
Therefore, compared to a recoil reflector of the same diameter, the lens would be much more powerful for throw, albeit only using 50% of available lumens (compared to a reflector that collects 180 degrees, near 100%)
——————————————————————————————————————————————
Is this correct?

The_Driver
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Enderman wrote:
Hey @The_Driver, could you look this over and confirm or deny for me?
——————————————————————————————————————————————
If the center spot intensity depends on the front area, then these two parabolic reflectors would have the same intensity:

(ignore the uneven distribution of the rays)
Both are 120mm diameter, but one collects 180 degrees (100%) of light, while the other collects 60 degrees (25%) of light.
.
.
So we take the second reflector, and make a lens with an equivalent focal distance and diameter:

Now both the lens and reflector collect the same cone of light, both 25%, and create the same size spot because the surface of both optics is at the same distance from the LED.
Assuming nothing is blocking the reflector, they should have almost identical peak intensity.
.
.
Then, taking into consideration that a wavien collar would increase the intensity by 2.3x, there is no center circle blocking light, there are no “beams” that would hold the center LED in place, and it is easier to provide cooling to an LED behind a lens rather than on a long heatpipe in front of the reflector, I would assume that the peak intensity with the lens would be close to 3x that of the reflector.
.
.
Therefore, compared to a recoil reflector of the same diameter, the lens would be much more powerful for throw, albeit only using 50% of available lumens (compared to a reflector that collects 180 degrees, near 100%)
——————————————————————————————————————————————
Is this correct?

You slightly misinterpreted the numbers in smas test of the Wavien collar. The 2.3x increase in Luminance was only observed a low currents of 700mA (So the resulting absolute luminance was not really higher than is possible without a collar). At maximum current the benefit of the collar decreases slightly to a maximum of 2.2x.

Also the hole in the center of a reflector doesn’t make a very large difference in terms of size (because the size of a circle increases with the square of the radius).

So generally you can just use the 2.2x factor for comparison between lens with collar and reflectors (unless there are additional factors like ar-coatings, special reflector coatings etc.).

The cooling of an LED with heatpipes could actually be better than in a normal flashlight if the heatpipes are connected to large enough heatsink and the LED is soldered directly onto them. In reality I think it will just be very similar though.

Generally while I do find this discussion here very interesting I don’t think the concept here makes much sense.
To me normal reflectors (~75% light collection), aspheric lenses with pre-collimators and TIR-Lenses make sense when designing a flashlight.
The recoil reflector has no large benefit in terms of throw compared to a normal reflector of the same size.
The real thing to do is just to use high-quality reflectors with a large diameter. Nobody is really doing that.

Another difference between recoil and normal reflectors is that with a recoil reflector the light that is not collected is wasted. It is not useful spill light for walking around because it goes into the wrong direction. It either goes behind the light or newer leaves it because of the flashight body.

Jerommel
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I think i showed ( http://budgetlightforum.com/comment/1138445#comment-1138445 ) the focal distance is more even and generally larger with a recoil, resulting in an even, tight beam, better than in a regular set up.

But here’s another thing, learned from reality:
Why is a Brynite 158 a similar (better even) thrower than a reflector light with the same diameter?
It basically uses the light that is otherwise the spill of a regular light.

I just tried this with the SupwildFire 53mm reflector light:
Took off the bezel and the lens, then i put the Brynite lens on top (actually just fits inside the outer rim of the reflector), and it is in focus, like the Brynite would be.
The lens only focusses the spill from the Supwildfire.

Now the recoil setup would use practically all of it together.
This is also visible in my comparison between a Jacob A60 and the mirascope recoil setup.
The far from perfect recoil setup was clearly a lot brighter.

So, what are we missing in all the theory that suggests otherwise?
Maybe it’s the radiation diagram that is confusing?
I think we’re missing something.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

The_Driver
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Jerommel wrote:
I think i showed the focal distance is more even and generally larger with a recoil, resulting in an even, tight beam, better than in a regular set up.

Have you tried using a flatter reflector in your “regular setup”?
A flatter reflector will usually produce a more pronounced spot and less corona around it compared to a deeper one.

Jerommel wrote:
But here’s another thing, learned from reality: Why is a Brynite 158 a similar (better even) thrower than a reflector light with the same diameter? It basically uses the light that is otherwise the spill of a regular light.

Well of course it’s similar when the diameter is the same. We have already covered that above. The apsheric should be slightly better because it doesn’t have the dead hole of the reflector in the middle.
Of course this only applies when both setups are perfectly focused, have the same LED at identical current and temperature and both lens and reflector are lit completely by the LED.

Jerommel
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The_Driver wrote:
Jerommel wrote:
I think i showed the focal distance is more even and generally larger with a recoil, resulting in an even, tight beam, better than in a regular set up.

Have you tried using a flatter reflector in your “regular setup”?
A flatter reflector will usually produce a more pronounced spot and less corona around it compared to a deeper one.

I was referring to the drawings here: http://budgetlightforum.com/comment/1138445#comment-1138445 actually.
A flatter reflector collects less light though.
In the drawing i use the most popular proportions.
Quote:
Jerommel wrote:
But here’s another thing, learned from reality: Why is a Brynite 158 a similar (better even) thrower than a reflector light with the same diameter? It basically uses the light that is otherwise the spill of a regular light.

Well of course it’s similar when the diameter is the same. We have already covered that above. The apsheric should be slightly better because it doesn’t have the dead hole of the reflector in the middle.
Of course this oly applies when both setups are perfectly focused, have the same LED at identical current and temperature and both lens and reflector are lit completely by the LED.

According to the radiation diagram of an LED the Aspheric lens would collect considerably less light, but it seems this is not the case.
Either way, the recoil set up will collect what a reflector light and an aspheric light would collect together.
And that’s consistent with the test set up results too.

Did you read what happens when i put the Brynite lens in the Supwildfire? (i edited the post a few times).

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Enderman
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The_Driver wrote:

You slightly misinterpreted the numbers in smas test of the Wavien collar. The 2.3x increase in Luminance was only observed a low currents of 700mA (So the resulting absolute luminance was not really higher than is possible without a collar). At maximum current the benefit of the collar decreases slightly to a maximum of 2.2x.

Oh I see now, missed that part. Still, 2.2x is very significant.

The_Driver wrote:

Also the hole in the center of a reflector doesn’t make a very large difference in terms of size (because the size of a circle increases with the square of the radius).

I was just calculating based on the design I had, which was a 11” reflector with a ~2” center hole and three 1/4” beams, compared to a 120mm lens.
The difference is 5x the area.

The_Driver wrote:

The cooling of an LED with heatpipes could actually be better than in a normal flashlight if the heatpipes are connected to large enough heatsink and the LED is soldered directly onto them. In reality I think it will just be very similar though.

Oh I wasn’t talking about a normal flashlight, I meant like having the heatsink directly on the back of LED in a lens configuration, would perform better than having the heatsink at the end of a long 6” heatpipe.
Like this:

The_Driver wrote:

Generally while I do find this discussion here very interesting I don’t think the concept here makes much sense.
To me normal reflectors (~75% light collection), aspheric lenses with pre-collimators and TIR-Lenses make to me sense when designing a flashlight.
The recoil reflector has no large benefit in terms of throw compared to a normal reflector of the same size.
The real thing to do is just to use high-quality reflectors with a large diameter. Nobody is really doing that.

I think the most valuable part of a recoil reflector is that you can collect near 100% of light, which is impossible to do with any other lens or regular reflector setup.
The only other way to collect 100% of light is a TIR, but the problem with those is that they suck for throw because they need to be so close to the LED (unless you made a giant 12” TIR)
Going for a recoil reflector that collects less than 180 degrees kinda defeats the point of high light efficiency for the beam, because a lens of the same diameter could be doing much better (over 2x lux)
Unless of course you use a recoil setup that is so large that a lens would be super expensive and impractical, so basically larger than 150mm.

The_Driver wrote:

Another difference between recoil and normal reflectors is that with a recoil reflector the light that is not collected is wasted. It is not useful spill light for walking around because it goes into the wrong direction. It either goes behind the light or newer leaves it because of the flashight body.

The idea here is that it behaves like a lens setup, where there is only beam and no spill Smile
Jerommel
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Updated the recoil reflector drawing in this post and the OP.

…but i’m having doubts about that lobed radiation diagram again…
To explain my doubts i will make yet another drawing, showing (also to myself) that an aspheric light like the B158 only uses the spill of a reflector light like the HD2010 or that Supwildfire i mentioned (same reflector).
Yet both lights have a similar output.
So my original motivation for a recoil light is still the same: it will use both, practically all of it.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Enderman
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Jerommel wrote:
Updated the recoil reflector drawing in this post and the OP.

…but i’m having doubts about that lobed radiation diagram again…
To explain my doubts i will make yet another drawing, showing (also to myself) that an aspheric light like the B158 only uses the spill of a reflector light like the HD2010 or that Supwildfire i mentioned (same reflector).
Yet both lights have a similar output.
So my original motivation for a recoil light is still the same: it will use both, practically all of it.


You need to know the depth of the reflector and the focal distance of the lens to be able to compare the % of light they collect properly.
Just the diameter isn’t enough.
Jerommel
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Enderman wrote:
Jerommel wrote:
Updated the recoil reflector drawing in this post and the OP.

…but i’m having doubts about that lobed radiation diagram again…
To explain my doubts i will make yet another drawing, showing (also to myself) that an aspheric light like the B158 only uses the spill of a reflector light like the HD2010 or that Supwildfire i mentioned (same reflector).
Yet both lights have a similar output.
So my original motivation for a recoil light is still the same: it will use both, practically all of it.


You need to know the depth of the reflector and the focal distance of the lens to be able to compare the % of light they collect properly.
Just the diameter isn’t enough.
Of course. Smile
But did you read about the B158 lens in the Supwildfire?
Quote:
I just tried this with the SupwildFire 53mm reflector light: Took off the bezel and the lens, then i put the Brynite lens on top (actually just fits inside the outer rim of the reflector), and it is in focus, like the Brynite would be. The lens only focusses the spill from the Supwildfire.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Enderman
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Jerommel wrote:
Of course. Smile
But did you read about the B158 lens in the Supwildfire?


Oh no I didn’t read that part.
How do you know the output is the same? Has it been measured in an integrating sphere?
The reflector should have near 100% lumen output since when measured in an integrating sphere it will count both the spill and spot lumens.
The lens should have about 50% lumen output if it is F0.5 and collects 45 degrees half angle.

It honestly would not make much sense for the lens and reflector to have anywhere near the same lumen output.
EDIT- that’s not accounting for the fact that a reflector would probably be like 75% efficient while a lens is 90%+.

Jerommel
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I know it’s approximately the same beam output (not counting the spill from the reflector light like you would in an integrating sphere of course) because i have compared the B158 with a C8 when they both had XP-L HI on 2.8 Amperes.
I’ll do some further testing with that light and the B158 lens though.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

The_Driver
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Enderman wrote:
EDIT- that’s not accounting for the fact that a reflector would probably be like 75% efficient while a lens is 90%+.

What do you mean with this?
Normal smooth Aluminium reflectors have ~90% reflectance in the visible range. This is very similar to the 90% transmission rate of good plastic lenses and 92% of glass (depending on type…).

Enderman
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The_Driver wrote:

What do you mean with this?
Normal smooth Aluminium reflectors have ~90% reflectance in the visible range. This is very similar to the 90% transmission rate of good plastic lenses and 92% of glass (depending on type…).

Aluminum electroformed reflectors are about 90%, but a chunk of aluminum that is milled on a lathe or pressed/stamped and then polished is a lot less.
Most regular flashlights (especially budget ones) do not use electroformed reflectors because of the extremely high cost.
And then there’s the super budget flashlights which use a piece of plastic coated in reflective spray paint, which is just horrible.
Enderman
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Jerommel wrote:
I know it’s approximately the same beam output (not counting the spill from the reflector light like you would in an integrating sphere of course) because i have compared the B158 with a C8 when they both had XP-L HI on 2.8 Amperes.
I’ll do some further testing with that light and the B158 lens though.

Oh I see what you mean, the amount of light in the spot.
Yeah, the closer it is to F0.5 the closer they will be to eachother in terms of lumens in the spot.
The reflector will have a bigger spot/corona though.
Jerommel
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Enderman wrote:
The_Driver wrote:

What do you mean with this?
Normal smooth Aluminium reflectors have ~90% reflectance in the visible range. This is very similar to the 90% transmission rate of good plastic lenses and 92% of glass (depending on type…).

Aluminum electroformed reflectors are about 90%, but a chunk of aluminum that is milled on a lathe or pressed/stamped and then polished is a lot less.
Most regular flashlights (especially budget ones) do not use electroformed reflectors because of the extremely high cost.
And then there’s the super budget flashlights which use a piece of plastic coated in reflective spray paint, which is just horrible.
I think they all use condensed aluminum vapor as a reflective surface though.
Iirc they do that in a vacuum chamber with some pure aluminum on a tungsten filament, vaporizing the aluminum which is then caught on the reflector surface.
Even on cheap plastic reflectors they do this.
The Jacob A60 is a good example of how good a plastic reflector can be.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Enderman
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Jerommel wrote:
I think they all use condensed aluminum vapor as a reflective surface though.
Iirc they do that in a vacuum chamber with some pure aluminum on a tungsten filament, vaporizing the aluminum which is then caught on the reflector surface.
Even on cheap plastic reflectors they do this.
The Jacob A60 is a good example of how good a plastic reflector can be.

The efficiency is still very low.
http://www.candlepowerforums.com/vb/showthread.php?166583-Reflector-effi...
The material below the surface matters too, and so does the surface flatness.
You can’t just coat anything with aluminum and get near 90% reflectivity.

The only way to get close to 90% is with an electroformed reflector.
A Rhodium electroformed reflector is about 80%, when coated with aluminum it is ~90%.
Silver can get you up to about 95%+ but with the cost going up exponentially, and also less durability.
A first-surface cold mirror (glass) can get 99%+

Jerommel
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Enderman wrote:
Jerommel wrote:
I think they all use condensed aluminum vapor as a reflective surface though.
Iirc they do that in a vacuum chamber with some pure aluminum on a tungsten filament, vaporizing the aluminum which is then caught on the reflector surface.
Even on cheap plastic reflectors they do this.
The Jacob A60 is a good example of how good a plastic reflector can be.

The efficiency is still very low.
http://www.candlepowerforums.com/vb/showthread.php?166583-Reflector-effi...
The material below the surface matters too, and so does the surface flatness.
You can’t just coat anything with aluminum and get near 90% reflectivity.
I assume this also depends on the thickness of the layer.
I’ll have a read in that topic you link though.
Quote:

The only way to get close to 90% is with an electroformed reflector.
A Rhodium electroformed reflector is about 80%, when coated with aluminum it is ~90%.
Silver can get you up to about 95%+ but with the cost going up exponentially, and also less durability.
A first-surface cold mirror (glass) can get 99%+
There’s often a layer of copper coloured metal between the aluminum cup and the relfective layer.
Is that rhodium?
And what does ‘electroformed’ mean?
Is that the process of adding the layer(s) or to form the cup?

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Jerommel
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Silver.
Can be applied DIY.
No experience with that.
But once you have a well shaped parabolic dish…
Hmmm…
Interesting (maybe).

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Jerommel
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Just found out Pelican has some recoil flashlights.
They seem to be designed by Stevie Wonder though…

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

Enderman
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Jerommel wrote:
There’s often a layer of copper coloured metal between the aluminum cup and the relfective layer.
Is that rhodium?
And what does ‘electroformed’ mean?
Is that the process of adding the layer(s) or to form the cup?

Electroforming is when particles of metal and electrodeposited onto a super-precise mandrel which almost perfectly reproduces the shape of the mandrel.
Basically it makes a very precise and smooth surface.
It’s more durable and economical than glass reflectors but still far more expensive than anything you would see in a typical flashlight.
Stuff like the maxabeam and cinema projectors use electroformed reflectors.

And no, rhodium is silver coloured.
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@Jerrommel: if you want to compare the “lumens in the beam” just measure the spot size and the lux of each and multiply these values with each other.
Lux = Lumens / m^2 => Lumens_in_beam = Lux x size_of_beam

Concerning reflectors:
Electroforming is a process that concernes the shape of the reflector (the accuracy of the parabola). It effects the throw of a light. The larger the difference between the size of the reflector and the size of the light source, the more accurate the reflector needs to be (if one wants the reflector to be completely lit up by the light source which is needed for maximum possible throw). The base material is usually nickel. It shouldn’t have too large of an effect on reflectance.

Because of their tiny size Xenon and Mercury short-arc bulbs require electroformed reflectors for maximum performance. The Maxabeam is a very good example of this. The tiny spot inside the arc (surface area maybe around 0.125mm^2) can only be focussed this way.

I have never seen a light with a polished reflector. I think it would be noticeably worse than what we are used to, even from cheap LED lights. I gather from the forums that aluminium reflectors are usually more precise than plastic ones (Maglite, Fenix etc.). This can already have an effect when using smaller LEDs like the de-domed XP-G2.

A bad example of an aluminium reflector is the one in my Trustfire X7. Is has a noticeably imperfect shape. A de-domed XP-L lights up maybe 90 percent of it.

Concerning Rhodium:
Rhodium is a special coating used for electroformed reflectors. It is very expensive (type “rhodium price” into Google…) and is considered the most robust coating in terms of corrosion resistance (salt water…) and resistance to strong UV radiation (Mercury bulbs…). It’s downside is the lower reflectance of visible light compared to aluminium and other coatings (70-80 percent). For short-arcs this usually doesn’t make much of a difference though.
These days there are also newer coatings like enhanced rhodium which might be a better compromise in many cases.

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Thanks for explaining, guys.

I read something about dielectric coating being even better, but i don’t know what that entails. All i know is that it’s expensive. Big Smile

So for this light it will have to be a decently machined aluminium dish that needs to be coated with aluminium vapor, basically like the average flashlight reflector.

Since it will be (in my view) not larger than 5 inches in diameter, i think it can be done good enough.

For DIY you could perhaps form a dish from sheet metal (aluminium, brass, whatever) and put silver on it yourself.
But i suspect silver will not want to stick to aluminium somehow, but that’s just a hunch.

..waiting for parts..

Still looking for 5” parabolic reflector (for recoil light)

smokuxx1987
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Great idea, I’m in.

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