Optic Modding, floodier beam?

Flashlight Modding and DIY Parts
1

Has anybody here tried modifying an optic to achieve a different beam profile? I’ve been playing around with the idea of cutting the optic on my dual channel IF25 so I wanted to see if anyone else has tried their hand at this first.

It has 2x sst20 hi cri and 2x osram W2. I like how throwy the W2 channel is(though more throw would be appreciated if there existed a throwier quad optic), but I want to the sst20 channel to be more floody, specifically have less of a hotspot and spread the beam more evenly. I have already frosted over the sst20s, but I’m still not satisfied w the result.

My feeling is that this must be achievable by removing material from the optic so that it doesn’t focus the light as much, but I’m not sure where to start. I’m thinking there are three options: 1. drill out the hole in the middle of the optic, 2. shave down the sides of the cone, or 3. cut the cone off entirely. I feel option 2 is more likely to result in a good beam, but option 1 would be a cleaner process. Option 3 I am sure would result in a floody beam, but would likely result in a lot of light being lost in the head. I honestly am not looking for extreme output with this flood, so I might even be willing to make that sacrifice.

Does anyone have, or know someone who has, experience with this? Any tips or half baked opinions would be greatly appreciated.

2

https://www.reddit.com/r/flashlight/comments/qwqtkk/i_just_did_quarters_for_my_dc_fix_dual_channel_kr4/

3

With TIR optics, the main reflector portion is the back surface of the cone. The lens portion in the center bends light that in aluminum reflector would become the spill.

  • Drilling a hole through the center of the optic probably won’t make the beam any floodier as it wouldn’t affect the main spot.
  • You could try lightly sanding the back of the cone, but this could be very risky. It might end up destroying all the reflective properties of the optic leaving you with a mule.
  • Safest option is probably to stick to modifying the front surface of the optic, either by sanding it or using diffusion tape like DC Fix. This should diffuse the beam.
  • If you’re still not satisfied with how floody the beam is, I recommend swapping the SST-20s for a larger less intense LED, such as LH351D.
4

thanks for the tips firelight, that’s really helpful. I was under the impression that tir optics worked with refraction only, I didnt realize the surface of the cone is actually reflective… perhaps then sanding down the surface of the cone where it attaches to the flat would shorten the effective reflector portion, causing more spill?

Unfortunately I think it will be impossible to source LH351D while moving around south America, but would this emitter really make a big difference?

If I were still back home I would cut and epoxy 2 quarters of a narrow carclo optic with two quarters of a wide optic, that would have been great.

5

So I did some reading about TIR on wikipedia and it seems the surface of the TIR is not reflective, but rather the light is reflected due to the refractive properties of the plastic. The angle of refraction of the light exiting the optic is greater than the angle of the light to the optic surface, causing the light to reflect back into the optic until it exits out the front of the optic, where the angle of incidence is greater than the angle of refraction.

By this reasoning, removing material from the surface of the cone, so long at the surface of the cone is perfectly smooth, would actually just cause the beam to narrow, until too much material is removed causing the light to not reflect off the surface of the optic. We could assume a spot optic would already be optimized for maximum throw, so removing material would likely increase angle of incidence too much, causing the light to pass through the optic without being reflected and focused at all. Also, if the surface of the cone is not perfectly smooth, there would be considerable light loss do to the inconstancies causing a higher angles of incidence, allowing light to pass through the optic without being reflected, or light being reflected the wrong way.

This would also mean that removing material from the inside of the optic would have no effect whatsoever.

Doing as I suggested in the previous comment should work, allowing light that would otherwise be reflected at the top of the optic and focused into the spot to instead continue its path into the spill, due to the higher angle of incidence, or be reflected at a more severe angle into the spill as well. The problem with this is that the optic on the IF25 has each optic cone overlapping a couple millimeters, which would make the execution of this difficult, and might result in a wonky beam.

Unfortunately I wont be able to source a carclo optic, but if I did I would try cutting a couple mm of the top of the cone inversely, so that it tapers back a bit. Seeing as I only have this optic to work with, I will have to stick to modifying the surface. I might try sanding with heavy grit and then cutting grooves into the optic with a razorblade, causing a the light to reflect off the grooves and spread. Same concept as in an elliptical optic, but I would cut a grid with diagonals to disperse the light in all directions. In theory, making the exit surface concave should spread the light evenly as well. I might go this route, but i’m concerned that having an exit surface that isn’t smooth would cause the light to reflect in weird directions causing output loss. I’ll start with the first method and try the concave if I don’t like the results.

Some good ideas spinning in my head I think, I’ll probably try something here soon, and I’ll post some beam shot comparisons when I do.

6

As mentioned already… DC fix will spread and smooth the beam, and is easy to try. If you don’t like it, simply remove it.

I prefer a sliced 351D to sst20. I’ve tried a lot of 351D and SST20 LEDs in 4000k and 5000k from various vendors.
At low currents, a good sliced 351D looks better than any SST20 I’ve found (to me).
Slicing the dome does narrow the 351D, but it is still less throwy than a sst20.

This is what I plan with my IF25s when they arrive.

One will have sliced 351Ds in 5700k and 3000k for tint ramping.
One will have a sliced 351D for flood and OSRAM W1 for throw for beam ramping. I’ll also add DC Fix for the flood side. I have various roughness options from Boaz to try.

Good luck!

FB

7

those sound good

some pics of a recent mod… to LH351D, both sliced and not sliced… in the host I used, the unsliced has a better beam, though not better tint… tradeoffs

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not shaved:
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8

I would start with sanding down the top of the optic to make it frosted. That will make the beam more floody. That seems to be the difference between the Carclo 10622 and 10623 quad optics, but I could be wrong.

You can do the same thing with sanding the lens, unless the Sofirn comes with an AR lens. It’s hard to remove the coating from an AR lens.

9

I also have a pair of V11Rs. Both have shaved 351Ds.
One has a 5000k and the other a 4000k. Both from AEDe and some of the best 351D tints I’ve found.

That reflector seems to not like the shaved 351Ds. I also had beam “issues”. The beams were improved with some DC Fix.

I also have a copper tool with 219b, but in 4000k.
It seems we have similar taste in lights.

FB

10

yes, you have very good taste :+1: