I need some experienced replies on reflector design for a custom SCC P7 flashlight

[jusval]

Hello,

I have made several lights with the P7 emitters. Modified Maglites. I really like the P7 and I would like to make a light that would throw farther than the ones I've done with Mags. What I'm looking for is to put all the light into a spot of approximately 20' diameter at 500 yards.

I am not an engineer or designer. I don't have the knowledge that I need. I would think that if a reflector was designed correctly, it would be able to put all the light into a spot like the one I referred to above. By all the light, I mean not having spill, containing the majority of the light into the spot.

I would Assume that there are formulas for figuring out how a reflector needs to be shaped for a specific purpose like the 20' spot. I would also Assume that there's software for it, so that it's easy to find the answer. My Assumptions are usually not correct, but that's what I am looking for. Someone who knows the method for figuring it out.

My feeling is that a deep reflector with not much taper (degree of angle?) would be what is needed, but I feel there's a lot more to it than that. Most likely there's not a stock reflector that would work. I would think that a reflector could be turned out of Aluminum and plated.

So, I'm looking for some answers on if it can be done, is there something already out there (like the Tiablo A10 reflector), is there a way I can figure it out, or does someone know of software available?

Thanks in advance for your answers,
Justin

 

[HarryN]

I have traveled this road before so perhaps I can save you a little time and money. Then again, others tried to tell me this same thing and I didn't listen to them. :shakehead

There most definitely is software out there to do LED optics design, and it has gotten much better over the last 5 years. The first step is to go to the supplier of the LED and get the ray tracing (light output simulation) for that particular LED. If this is not available, then sometimes you can find a similar LED.

In the case of single die LEDs, this is very available. I was using a 4 die Lux V at the time, so not so different than your project from an "interesting challenge" perspective.

The software to design a reflector is very good, but, it is very good in the hands of an experienced user. It is typically designed to be used by a trained, optical engineer. That does not mean you cannot do it, it just will take time, and the s/w is not cheap.

 

[HarryN]

Once you have this reflector designed, then it will need to be fabricated. While in theory this is not so hard (program the cnc, let it rip), in practice, optical quality surfaces are a PITA to actually make.

There is a machinist I know from frequenting a different forum who makes optical surfaces for a living. His sig line (in part) is: "very much like trying to herd cats."

Once the surface is made, it will need to be coated with a highly reflective material, then a protection layer (usually by vacuum coating). In bulk, these are reasonable things to do, but for small qty, it is massively expensive.

I spent literally thousands on making the optical assy in my sig line "breeze" light. (too small for standard offerings, even today) It works, but is way to expensive to produce for anything but specialized use.

 

[HarryN]

Perhaps instead, it would be better to consider an optic, such as a large aspherical lens. These are not that expensive and available off the shelf in small qty. You can play with these easily at home.

Last, but not least, I think you will not get enough light to be happy from one P7 at that distance. The light you describe is closer to 1,000 lumens minimum - not from the LED, but from the front of the light. This sort of means you need about 2,000 lumens of "rating" in the LED, or at least in that range.

There are not many LEDs in that range available yet, so it might be useful to consider instead using a set of single die packages with available reflectors.

JMHO.

 

[jusval]

HarryN,

Thank you for all the replies. I think that you did save me lots of time and Money. I can see where it's out of my grasp. It was just a thought, but many of my thoughts are better left in the back room with the cleaning supplies.........

What about any current reflectors that might get in the general direction of where I want to go? Like the Tiablo or some other? I can see a P7 won't be all that bright at the distance, but still it's better for me than an incan which puts out excessive heat.

I have seen several threads on aspherical optics, but the pictures I have seen, show just a square spot, which stays really small for very long distances. I don't think I can deal with the square spot (a matter of individual tastes, I think). I may try one, just to see for myself though.

Justin

 

[Gunner12]

A reflector will always give you spill unless it is not set up normally, which is what you don't seem to want.

You can look at a recoil type setup. Have the LED facing backwards towards the reflector. This will give no spill and almost all the light into the hotspot. You'll still need a pretty big reflector. You'll need a way to heatsink the LED though and I think this sometimes also gives a LED die shaped hitspot.

You don't need an ashperical lens to see if you like it. Just grab a magnifying lens or similar and play with it infront of the light.

As HarryN said, it could be too much work.

 

[HarryN]

If the setup is in perfect focus, then it will project the die shape, which is really not that nice looking but really throws.

You can also make it slightly out of focus, which starts to soften the edges and reduces the sharp grid like projection. The more out of focus, the better it looks, with slightly less projection. It is a matter of dial till you like the beam. That is what I did, but I was adding some additional optical elements to the design - just for fun.

Your idea is good, it is just a heck of a lot of work to pull it off.

I suggest you look at the beam throw of some of the modified SF M6 lights vs the modified versions. The goal you have is a lot of fun, but just take into consideration how much light is really needed.

 

[Der Wichtel]

you need a very deep reflector and then furthermore a second one directly over the led like a side emitting led.
Then you will have no spill but throw. I did some tests with the reflector of the ultrafire wf-600 which is a very deep one. It throws pretty good even with P7 inside. Maybe the reflector with the side emitting effect will give a more intense hotspot.

 

[jusval]

So, if I am getting the idea here, a reflector similar to a car headlight (not in shape, but in design), where the bulb has a plated cover over it, so that all the light side emits and the plated cover reflects too and eliminates the donught, is the way to get throw?

Theory? - if an LED could be designed the control the light emitted straight out the front of it, then there would be no need for a reflector?

I can see the idea of blocking forward light and forcing it back down into the reflector, where it would bounce out front, forcing more light thrown straight (not quite straight) out, with a deep reflector, with little angle.

So maybe that can be played with and it might be a little easier to experiment with a stock reflector and a front shield?

 

[HarryN]

There are LEDs that are "mostly" front emitting out there. There are also "side emitters" (Lumileds).