# Using LEDs with parabolic reflectors...



## louieatienza (Nov 19, 2018)

So I want to make a small searchlight around 12" diameter... Been reading on focal points on parabolic reflectors. Is it necessary to mount the LED at said focal point? Would simply mounting the LED at the mirror aperture work? Or would a secondary reflector or lens at the focal point be needed? Thanks in advance for your help!


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## Agpp (Nov 21, 2018)

You need to mount the LED at the focal point.


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## louieatienza (Nov 21, 2018)

I figured as such... But then since the emitter only throws in one direction, that would limit the size of the beam narrower than the actual reflector? Is there any way around that?


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## alpg88 (Nov 21, 2018)

bare leds usually have 90-130* beam. reflectors are not the best for leds, tirs are. if you want a thrower get ledil seanna lens


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## BVH (Nov 21, 2018)

> bare leds usually have 90-130* beam. reflectors are not the best for leds, tirs are. if you want a thrower get ledil seanna lens



The Syniosbeam must be an exception.

http://www.candlepowerforums.com/vb...omparison-Leopard-1-450W-Short-Arc-Tank-Light


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## alpg88 (Nov 21, 2018)

BVH said:


> The Syniosbeam must be an exception.
> 
> http://www.candlepowerforums.com/vb...omparison-Leopard-1-450W-Short-Arc-Tank-Light



what exactly are you trying to contradict? primary optic angle? the fact that tirs are more efficient then reflectors for leds?, `


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## BVH (Nov 21, 2018)

Simply that "reflectors are not the best for leds" is not always correct. Same with "if you want a thrower get ledil seanna lens" is not always correct.

The BLF GT could be added as an example of a very high performing led-reflector combination.


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## gadget_lover (Nov 21, 2018)

An led will work well with a appropriate parabolic reflector. post #25 of the thread https://www.candlepowerforums.com/vb/showthread.php?50720-KILLER-minimag-mod shows a minimag illuminating a palm tree 300 feet away. But read the rest of the post to see how it was made.

Dan


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## louieatienza (Nov 23, 2018)

Thanks for the replies... Gadget lover, cool thread! BVH, you own some amazing lights, thanks for your insight. I just picked up a BLF GT and very happy with it - for now.


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## louieatienza (Nov 23, 2018)

BVH said:


> The Syniosbeam must be an exception.
> 
> http://www.candlepowerforums.com/vb...omparison-Leopard-1-450W-Short-Arc-Tank-Light



I saw the build thread for that! EPIC! Enderman's skillset is second to none. I'd like to build something similar but in a smaller scale first... found a couple parabolic reflectors to experiment with, one cheap one and one not-so-cheap....


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## Agpp (Nov 27, 2018)

alpg88 said:


> bare leds usually have 90-130* beam. reflectors are not the best for leds, tirs are. if you want a thrower get ledil seanna lens



It would be very useful if you provided some more information on why would TIRs be better than reflectors.
Actually....I understand how TIRs can have larger working area at the same diameter and how total internal reflection is the most effective form of reflection. I also understand the relation between the amount of collected light, reflector proportions and emission profile.
Nevertheless I observe that in practical lights, the throwiest-for-diameter ones tend to use either aspherics or reflectors. This is something I don't understand, but would love to.

I would also like to understand how does Seanna work.....I would guess that it focuses the main lens on the front of the pre-collimating TIR, multiplying that TIRs surface luminosity. Which I would guess is not very high. But then it wouldn't work well, so I suppose at least one of those guesses is wrong.

If you can help me with understanding one of those things I would be much obliged.


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## louieatienza (Nov 27, 2018)

Agpp said:


> It would be very useful if you provided some more information on why would TIRs be better than reflectors.
> Actually....I understand how TIRs can have larger working area at the same diameter and how total internal reflection is the most effective form of reflection. I also understand the relation between the amount of collected light, reflector proportions and emission profile.
> Nevertheless I observe that in practical lights, the throwiest-for-diameter ones tend to use either aspherics or reflectors. This is something I don't understand, but would love to.
> 
> ...



I could not find a US supplier that stocks a Ledil Seanna. Because I'm curious, I back-ordered 2 since they're only something like $25 each. They come from Finland. But to me it looks like a lens focusing onto a Fresnel lens. They also claim 94% efficiency and 1* beam dispersion with an Osram Black Flat... I won't know till I get them, but have a nice small project for them when I do.


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## Agpp (Nov 28, 2018)

louieatienza said:


> I could not find a US supplier that stocks a Ledil Seanna. Because I'm curious, I back-ordered 2 since they're only something like $25 each. They come from Finland. But to me it looks like a lens focusing onto a Fresnel lens. They also claim 94% efficiency and 1* beam dispersion with an Osram Black Flat... I won't know till I get them, but have a nice small project for them when I do.



According to Ledil, Black Flat driven to 850 lm gives 956 kcd and 800 lm OTF. XHP35 HI driven to 2500 lm gives 1029 kcd and 2080 lm OTF.


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## alpg88 (Nov 28, 2018)

louieatienza said:


> I could not find a US supplier that stocks a Ledil Seanna. Because I'm curious, I back-ordered 2 since they're only something like $25 each. .



that is strange, they are over $50usd each, and they are available at mouser, they have 9 in stock as of 10am est


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## louieatienza (Nov 28, 2018)

alpg88 said:


> that is strange, they are over $50usd each, and they are available at mouser, they have 9 in stock as of 10am est



CDI sells them for half if I'm not mistaken.... Ill check mouser again but at $50 each that's a bit steep.

Just checked to confirm.... I do have 2 on back-order as I'm not exactly in a rush.... 6 weeks is fine for me.


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## alpg88 (Nov 28, 2018)

never seen anyone sell them for 25 before, but only looked in mouser and digikey. $25 is a much better deal, i was not aware of cdi store before, thanks for bringing it to my attention.

i wonder if there is a way to know if they are getting anymore in stock, if it worth waiting, cuz price is very attractive


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## louieatienza (Nov 28, 2018)

According to the sales rep they have a 6 week lead time.... So not holding my breath, but at $50 there are other options. It's nice however that its an integrated unit.


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## alpg88 (Nov 28, 2018)

louieatienza said:


> According to the sales rep they have a 6 week lead time.... So not holding my breath, but at $50 there are other options. It's nice however that its an integrated unit.



that seems too vague of answer, so i called them, they are not ordering to keep them in stock, this item is not popular, someone placed an order for 2 pc, but they have no eta on that yet. so unless people order, they will not reorder just to keep in stock, as they do with more popular items. can't blame them thou, i used to work in retail, if items sit on the shelfs too long they get lost, misplaced... etc so no surprises businesses do not stock items that do not move fast.

if you need one, 50 bucks may not be that terrible, but if you need several, might worth ordering from cdi and wait.


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## alpg88 (Nov 28, 2018)

Agpp said:


> It would be very useful if you provided some more information on why would TIRs be better than reflectors.



http://www.candlepowerforums.com/vb/showthread.php?385907-TIR-vs-Reflectors


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## BVH (Nov 28, 2018)

Where is the hard documentation in that thread that TIR's are better performers/are more efficient than reflectors with LED's?


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## alpg88 (Nov 28, 2018)

he was not asking for hard documentation, just some more information on why would TIRs be better than reflectors. that thread has that information.


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## louieatienza (Nov 28, 2018)

Silent Thunder Ordinance has a couple flashlights that use TIRs... I suppose you have to like the particular beam pattern they produce...


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## alpg88 (Nov 28, 2018)

louieatienza said:


> Silent Thunder Ordinance has a couple flashlights that use TIRs... I suppose you have to like the particular beam pattern they produce...



beam profile is something that can be very different in same lights between 2 different reflectors, as well as between 2 different tirs.

yes tirs capture and use more light emitted by led than a reflector, but a good reflector will still be better than a bad tir. in everyday use vast majority of people will not notice a difference, it is when you start building something special, it may matter a bit. we have seen great examples build with reflectors, and lenses. usually lamp reflectors are not that good with leds, but there are exceptions. 
in reality there aren't many good large trowing reflectors available for leds. if any. (there are few large ones at kd or dx, i tried 2 different, made for leds, but they were not true spot, narrow flood at best) ledil seanna tir lens is one of the few optics available for leds with an angle like that.


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## louieatienza (Nov 29, 2018)

All the TIRs I've seen are some molded plastic so I'm not so sure of their overall efficiency as to a high end reflector. Also I don't know of any available in larger (over 60mm dia.) so there's a distance limit as well.

I can't see why a catadioptric reflector system wouldn't be more efficient since there is no material but air for light to pass through. The problem is not with the reflector but the throw angle of the LED emitter, which RLT collars try to address.


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## Agpp (Nov 29, 2018)

louieatienza said:


> Silent Thunder Ordinance has a couple flashlights that use TIRs... I suppose you have to like the particular beam pattern they produce...



Which ones? I don't see any on their site.



alpg88 said:


> http://www.candlepowerforums.com/vb/showthread.php?385907-TIR-vs-Reflectors


Thank you. Frankly, initially I was disappointed with this thread as I view it as both incomplete and unorganized. But it did contain a single gem: a link to a custom TIR created by Ra:
http://www.candlepowerforums.com/vb/showthread.php?283513-Homemade-67mm-glass-based-TIR-optic!
Too bad the pics are dead. Anyway, it contained some actual numbers (though few of them), his experiments showed TIR to throw 3-5% less than aspheric. Furthermore, my personal pet peeve have been AR coated TIR lenses.
Some people speculate about them. Theory at my basic level shows no problems with implementing them. I searched for them, a lot. I failed to find a single specimen.
Now Ra is a person with enough knowledge to craft a working TIR, that's something. He doesn't say it clearly, but his statement seems to indicate that he has created a coated TIR. And makes it clear that he views it as a thing. This is the most reliable account I've seen so far.


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## alpg88 (Nov 29, 2018)

louieatienza said:


> All the TIRs I've seen are some molded plastic so I'm not so sure of their overall efficiency as to a high end reflector. .



yes optically clear polycarbonate, pmma and silicone, they are more efficient, since they capture all light from led, not so with reflectors, thou difference in efficiency is not night and day. there are different quality tir, as well as different quality of reflectors. 
a clear uncoated glass will block more light than a coated one. but it would seems like coating should be blocking light, not help more to go thru.


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## Agpp (Nov 29, 2018)

alpg88 said:


> yes optically clear polycarbonate, pmma and silicone, they are more efficient, since they capture all light from led, not so with reflectors, thou difference in efficiency is not night and day. there are different quality tir, as well as different quality of reflectors.
> a clear uncoated glass will block more light than a coated one. but it would seems like coating should be blocking light, not help more to go thru.


Efficiency = light_out/light_in
TIRs are normally quite inefficient, largely because being uncoated costs them about 8%, with further losses leading to overall ~85-90% efficiency. Note that lights that put a glass lens ahead of the TIR to protect it lose another ~3%.
Cheap alu reflectors have efficiency of about 85% and capture (this differs a lot) 65% of light leading to overall efficiency of ~90% before the light hits the lens and - as long as the lens is AR coated - a total of ~87%.
Overall - they are quite similar when it comes to efficiency.

Being able to capture more light results in optics designer having more control over the beam shape.


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## alpg88 (Nov 29, 2018)

Agpp said:


> Efficiency = light_out/light_in
> TIRs are normally quite inefficient, largely because being uncoated costs them about 8%, with further losses leading to overall ~85-90% efficiency. Note that lights that put a glass lens ahead of the TIR to protect it lose another ~3%.
> Cheap alu reflectors have efficiency of about 85% and capture (this differs a lot) 65% of light leading to overall efficiency of ~90% before the light hits the lens and - as long as the lens is AR coated - a total of ~87%.
> Overall - they are quite similar when it comes to efficiency.
> ...



silicone tir 94%
acrilic tir 90% 
pc tir 87-89%

reflector 90%



all from same manufacturer ledil, as you see material matters, same with reflectors, reflective coatings are not all same. 

i do agree, in normal everyday use, no real difference, but this thread is not really about what is generally more efficient, the guy want to build a spotlight, and as far as availability goes, ledil seanna is the best for that, there is no reflector on the market that will be better for such use. i'm not talking about exotic reflectors, that may or may not work. sure some apparently pretty good, but not easy to get.


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## louieatienza (Nov 29, 2018)

alpg88 said:


> silicone tir 94%
> acrilic tir 90%
> pc tir 87-89%
> 
> ...



Update: CDI sent me an email saying that the Ledil Seanna assemblies I ordered will ship on 12/4... Not bad considering the 6 week quoted lead time.

Efficiency aside, it's a pre-made, engineered product, making it relatively easy to implement. Not exactly DIY but we'll see how good it is in actual use.

Maybe parabolic reflectors are not as efficient, but currently they handle higher powered and larger light sources, something the Seanna line currently cannot do (they only have one size in their line.)

The idea had already been done by at least a couple folks...

http://budgetlightforum.com/node/41545

http://budgetlightforum.com/node/47242


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## louieatienza (Nov 29, 2018)

More...

http://budgetlightforum.com/node/63188


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## gadget_lover (Nov 30, 2018)

What I liked about the TIR was that you could get a very nice beam in a very compact form. It was nice for a light like the ARC series in the early 2000s.

Dan


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## louieatienza (Dec 1, 2018)

I have a few projects in the works... I started out toying with Fresnel lenses; fun for cheap. I do have an AceBean X80 for wide flood, and a BLF GT70 for some long throw fun. It's great to see people's reactions when I pull it out of the bag!

In the works - an aspheric lens thrower similar to Enderman's OptiForce, a small searchlight wth a retro-firing LED (have some nice parabolic reflectors already), and a light bar for my boy's Jeep for off-roading. 

I loved Enderman's SyniosBeam thread and always wanted to build something like it. Have a few LEDs to choose from...


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## louieatienza (Dec 13, 2018)

alpg88 said:


> that seems too vague of answer, so i called them, they are not ordering to keep them in stock, this item is not popular, someone placed an order for 2 pc, but they have no eta on that yet. so unless people order, they will not reorder just to keep in stock, as they do with more popular items. can't blame them thou, i used to work in retail, if items sit on the shelfs too long they get lost, misplaced... etc so no surprises businesses do not stock items that do not move fast.
> 
> if you need one, 50 bucks may not be that terrible, but if you need several, might worth ordering from cdi and wait.



Just to update, I have received both Seanna fixtures... and as a quick and dirty test I did a makeshift setup with a Black Flat and one 18650 cell. It looks almost like a thin laser beam shooting out of the lens! I do have some White Flats coming in, in both 1mm^2 and 2mm^2. I think the 2mm^2 should have better throw than the XHP35 HI. I do have some XHP35 HI, but have to still set up my test platform (buck/boost driver and 3S LiPo) before I can see what they do.


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## louieatienza (Dec 13, 2018)

Agpp said:


> Which ones? I don't see any on their site.
> 
> Storm of Ra - TIR + aspheric lens... Big throw with HUGE sharply demarcated hot spot. I think the best of both worlds, though the beam pattern would take getting used to.


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## Agpp (Dec 17, 2018)

Thanks for the info, I haven't seen the TIR mentioned before.


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