Reflector advancements are dead

[lctorana]

Soon, I'll try to make one with a more reasonable 50mm diameter...

Ra,
Any progress on the 50mm TR front?

 

[cerbie]

Hi, thread necromancers. :wave:

Why aren't optics more geared towards spill? Not necessarily in general, but why aren't there some that can best reflectors of the size in an overall balanced beam?

Consider the well-known Maglight reflector, with a LED, focused to a point. It's not the prettiest beam (not the ugliest, either, though), but it's very useful, with a good point, and lots of very dim spill. A great walking beam.

Now, consider a TIR beam that made a ~5 degree cone, instead of that point, and also gave 90-110 degrees of even but dim spill. In usefulness, it would blow the 'normal' beam away, and not be so big as even the small reflectors that do it, on top of being able to offer a better quality wider spill, and that oh-so-cool die projection, when you get it fit just right.

 

[maxa beam]

Hi Gunner12,

I must slightly correct you on something:

If you talk about 3% loss of light, it would mean 97% bulblumens are converted into torchlumens.. That is not the case:

The conventional shape of most reflectors causes a loss of bulblumens, which is much more than 3%.. more like 25-35%

The high reflectivity of the reflector in my mini-HID shurely contributes in a better bulblumens-torchlumens ratio, but the most important is the the fact that the high reflectivity preserves the surface brightness of the source. Better throw is the result of that.


As for most efficient reflectors: Few months ago, I made a glass-TIR reflector (Total Internal Reflection) for use with the Seoul SSC P4 emitter..

The theroretics behind it:

Shot at 2007-09-28



A 30mm diameter version I finished earlier:

TIR means 100% reflection inside the reflector (optical fact, law of light). That, with a collimating lens at the center, and high performance coatings, creates a whopping 95% total efficiency. And this indeed does mean converting 95% bulb-(or emitter-) lumens into torchlumens!



I already build a light with a glass-TIR 15.5mm diameter reflector:

When I have the time, I will post a thread on this light in the Custom/modified section of these forums..



Regards,

Ra.

Whoo, RA. Fancy optics, there. Nice mathness. Imagine a 3 thousand lumen torch with one of those suckers. Expensive, probably, but, meh.

 

[Ra]

Hi, thread necromancers. :wave:

Why aren't optics more geared towards spill? Not necessarily in general, but why aren't there some that can best reflectors of the size in an overall balanced beam?

Consider the well-known Maglight reflector, with a LED, focused to a point. It's not the prettiest beam (not the ugliest, either, though), but it's very useful, with a good point, and lots of very dim spill. A great walking beam.

Now, consider a TIR beam that made a ~5 degree cone, instead of that point, and also gave 90-110 degrees of even but dim spill. In usefulness, it would blow the 'normal' beam away, and not be so big as even the small reflectors that do it, on top of being able to offer a better quality wider spill, and that oh-so-cool die projection, when you get it fit just right.

You are absolutely right!

But not everyone meight think that way: Some very much like the "spill-less" , high-throw beam of an aspherical lens-Cree setup..

In most cases, when you are able to make a balanced system with a few degree spot and still very usable sidespill, the light within the spill is not used for the spot: Throw will be less, but not much, not everyone knows this, and not everyone wants to lose even 5% throw!

Glass-based TIR-optics can be made with exactly the beampattern as you desire: A small area around the center-hole must be given a slightly different radius or curvature: The most of the reflector-surface still creating pure throw, the center for sidespill.

One of the big advantages of glass-based TIR is: You have 95% torchlumens to play with. You only need some 10% for decent sidespill: Still a very reasonable 85% left for Throw!

Why only 10% is needed for spill: Light followes the reverse square law: You need a certain amount of light to enlighten an object at, lets say 50 yards.. For the enlightening of an object at half that distance, you only need one fourth of the light! Beleve it: It is a fact!
So, as the objects one wants to enlighten with the sidespill are usually much closer, you don't need much light to effectively enlighten them!

Back to TIR-optics: They have one disavantage: Very poor (practically none!) focusabillity! They only work fine, exactly matched to the type and geometrics of the emitter, and with the emitter-die exactly at focus!

So, like I said earlier, if you want a beampattern with a perfect balance between throw and flood, it can be done, but as the acryllic-TIR manifacturers didn't come up with that idea (yet..) you propably must do it yourself.. (I do..) The problem is: practically no CPF-member is capable of doing this.. And I don't have the time to make them for them.. (and they will be expensive too: need lots of time)


I hope you're still awake after this...:sleepy:


Best regards,

Ra.

 

[lctorana]

Amen, Ra.
(ancient Egyptian joke)

Earlier in this thread, you mentioned looking into making a 50mm TIR.

(I tried to ask about that a few posts up, but couldn't spell "TIR"...)

I would love to buy a 50mm TIR, but can't find anything larger than 35mm for a single LED...

Bruce.

 

[Ra]

Amen, Ra.
(ancient Egyptian joke)

Earlier in this thread, you mentioned looking into making a 50mm TIR.

(I tried to ask about that a few posts up, but couldn't spell "TIR"...)

I would love to buy a 50mm TIR, but can't find anything larger than 35mm for a single LED...

Bruce.

Sorry, still "looking into making.." Can take another year.. not shure.. And if I ever start selling a few of them, they will be expensive: $250 (-ish)

I'm not shure if anyone is stupid (no offence..) enough to meet that prize!

But: When type of emitter and desired beampattern is known, things will be perfect!


Ra.

 

[divine]

Hey Ra,

When I picture the TIR in my head, I always think it would be better with a reflector around it. Why doesn't anyone put a reflector around this?

Your diagram is very nice, it explained a few things about TIR by itself.

I'm surprised that you don't get more light loss just from passing through that much glass, I mean, we lose 2% going through a UCL, don't we? Your light must be passing through 8-10 times more glass before it exits the light.

 

[Ra]

Hey Ra,

When I picture the TIR in my head, I always think it would be better with a reflector around it. Why doesn't anyone put a reflector around this?

Your diagram is very nice, it explained a few things about TIR by itself.

I'm surprised that you don't get more light loss just from passing through that much glass, I mean, we lose 2% going through a UCL, don't we? Your light must be passing through 8-10 times more glass before it exits the light.

Reflector around it?? It is a reflector! And a very efficient one: Inside, 100% of the light is reflected, no conventional reflector can do that!

If you would mount a reflector around it, it would simply not receive any light !

The UCL losses are mainly reflection-losses at the surfaces, only 0.1-0.15% is lost by absorbtion inside the UCL ! The transmission of the optical grade BK-7 I use for my TIR-optics is 99.4% per cm thickness..


Best,

Ra.

 

[maxa beam]

You know, guys, there ARE flashlights out there with TIR'S on them.

 

[Ra]

You know, guys, there ARE flashlights out there with TIR'S on them.

:duh2:... Really??? :thinking:...

Sorry, just teasing you..

No offence,

But we all know that maxa beam... But those are acryllic-based TIR's: 'only' 90% efficient (which is still great ofcource). But they have huge thermal expansion, and can easily be damaged because the acryllic material is very weak. They are only aviable in a few small sizes.
But they are a cheap alternative..

We are talking glass-based TIR's.

So only if you know any flashlights with glass-based TIR's, we're interested..


Best,

Ra.

 

[LukeA]

What about polycarbonate? It can be made plenty clear enough. Is the coefficient of expansion better?

 

[enLIGHTenment]

You know, guys, there ARE flashlights out there with TIR'S on them.

Not very many that are well built, have usable interfaces and use modern LEDs.

 

[Ra]

What about polycarbonate? It can be made plenty clear enough. Is the coefficient of expansion better?

I don't have info on that..

But I know that polycarbonate lenses still need a hard protective coating to protect them from getting scratched easily..


Ra.

 

[NA8]

Wow, great thread. Very interesting stuff on TIR optics. Looking forward to what happens. I hope we don't end up with most flashlights having cheap optics that have a tiny hot spot and zilch spill. I don't mind having one throw monster flashlight, but I prefer something with spill to light up a room or hallway. Although the technology is dated, my 4C Maglite with a Malkoff drop in has a wonderful ability to focus from a strong hotspot to almost no hotspot. Lots of losses, but the Malkoff has lots of lumens to start with. Looking forward to the new UA2 Surefire. Sounds like it's going to be a fun light.

 

[copperfox]

Why does it seem that most non-focusable flashlights have such a concentrated hotspot? I know the companies are probably aware of the ugly donut hole caused when the bulb/emitter is moved up or down relative to the reflector, so they just concentrate the beam to a single spot to avoid this. My question is: Why can't a reflector be designed to give a wider hotspot without any artifacts?

Frosting the bulb and texturing the reflector are good starts, but I can't understand why the shape of the reflector can't do this by itself.

Kudos to the Novatac for its beam pattern.

And one more thing! Why don't moden LEDs have circular phosphors?! The Cree looks like a square with a grid on it, the Rebel looks like a waffle, and the Seoul is just kinda square. Wouldn't circular phosphors result in a better beam pattern? :thinking:

Edit: Surefire has done a good job of improving the beam pattern for hotwire lights, but what about the poor people who don't want to spend so much money or use a flashlight that doesn't take CR123s?

 

[scaredofthedark]

sorry to bring up a month old thread but im wondering
would TIR also work with incans, as it works with LEDs?
or is the light emitted from the filament too scattered to design a proper optic for it

 

[Zoofa88]

There seems to be a couple of facts with lights:

1. The light engines will get much more powerful
2. Battery technology will improve

So this leaves the reflector...

The amount that can be changed on reflectors is finite and there are only a few companies trying unique reflector designs.

It also leaves the user interface, the form factor, the construction materials, and so on. There are many things that contribute to a quality flashlight that have nothing to do with the beam.

 

[Illum]

the Rebel looks like a waffle

:lolsign: I had to laugh, sorry

I think its more economical to build them into squares, considering theres going to be alot of waste if the dies are to be cut from squares into circles. Some companies like Edison have been putting effort in compensating the "curves" using added phosphor layers around the die. As of the results I don't know of any comparison threads that discusses specially on why dies are the way they are

 

[2xTrinity]

Why does it seem that most non-focusable flashlights have such a concentrated hotspot? I know the companies are probably aware of the ugly donut hole caused when the bulb/emitter is moved up or down relative to the reflector, so they just concentrate the beam to a single spot to avoid this. My question is: Why can't a reflector be designed to give a wider hotspot without any artifacts?

A reflector can be desigened to produce just about any beam pattern imaginable. The fact is, most flashlight designers simply don't design their products with actual usability in mind.

sorry to bring up a month old thread but im wondering
would TIR also work with incans, as it works with LEDs?
or is the light emitted from the filament too scattered to design a proper optic for it

I haven't heard of incan being used with TIR, but incan can be used in a "projector" configuration, that is, an aspheric lens, along with an ellipsoidal reflector.

A parabolic reflector, what most reflectors in flashlights are, is basically an ellipse with one focal point at "infinity" so that all the light exits in a straight line. With an ellopsoidal reflector, you concentrate all the light from the filament back down to a single point, coinciding with the focal point of a lens. If the spacing between the two foci in the ellipse is the same as the focal length on the aspheric, You can then use the lens to direct ALL the light from the filament.

If a flashlight were to be made that actually focused the light output using optics, rather than simply moving a parabolic reflector into and out of focus, you could have spot to flood focusability WITHOUT any donut holes.

 

[yaesumofo]

I believe that the TIR OPTIC which surefire uses in the E1B is made from PYREX glass.
TIR optics are very cool. they work as well as reflectors IMHO. They are very efficient. They do a very good job of concentrating the light from an emitter and creating a beam from it.
I am not sure why but I think that TIR optical based systems are becoming more and more popular. Surefire has spent BIG money on R and D for the purpose of designing these systems for military focused equipment.

We will be seeing more optics than reflectors in the future.
That optic you made is very cool I wish I had the knowledge and equipment to do that.
Yaesumofo

The TIR-optics used in flashlights by some brands, are acrylic based: More fragile, can easily be damaged, huge thermal expansion. But they are easy to make. (at $3-$6 each)
They have about 90% efficiency, which indeed is much better than conventional reflectors

Glass-based TIR-reflectors are much, much, much harder to make ! I don't know anyone or any brand that makes them.. Do you ??


Edit: Oh.. I forgot: The main reason people are not jumping onto this is the lack of many sizes: The acrylic optics are available in only a few small sizes.. Soon, I'll try to make one with a more reasonable 50mm diameter.. Another problem is: Being from massive material, larger diameters TIR's will be heavy!


Regards,

Ra.