Is there any adjustable beam optic available?

Need something small that will fit on a headlight and allow the beam to be coned down to a spot.
Thanks

okent said:

Need something small that will fit on a headlight and allow the beam to be coned down to a spot.
Thanks

Click to expand...

There are plenty of optics available that do this. However, in order to cycle between flood and spot you have to change the distance between the lens and the LED. This is typically done by having a sliding bezel with the lens mounted on it.

As such, you're going to have a very hard time trying to retrofit such a lens into your presumably non-zoom headlight. Your headlight won't have the zooming bezel so there's no easy way to mount the new lens.

Your best bet is to buy a zooming headlight that comes with the lens and sliding bezel, then modify it as desired with different LED and driver.

I guess it would be helpful to give a back story. I started building my own medical headlights over 15 years ago when Luxeon first came out with their super bright led's. There was zero product on the market and even though the things I was making looked rough they worked much better than old incandescent technology that was 10 times as much. I've switched to Fenix MC11's now but they still aren't exactly what would be best.

I don't really need an adjustable spot but something that narrows the beam down to 2-5 degrees or so with a minimum of side spill. I'm working with Cree XPG2's right now and found an optic that seems perfect but they are sold out.
https://www.ledsales.com.au/index.p...ucts_id=1539&zenid=s6kalms7hntcfd85n4s46cd7c6
I can make my own housings and such and have access to cnc and 3d printing so it's really just getting the components/driver/switches and drawing it up and assembly.
I have zero background in electronics so I am using luxdrive micropucks.
Ideal optic width would be 20mm or less.
Thanks

An aspheric lens, such as that used in typical zoom flashlights, would do the trick. You can find very high quality ones for sale at Edmund Optics. Mount the lens close to the focal point for minimum spill. 20mm aspherics are a pretty common size. You shouldn't have a problem finding them.

If you need something cheaper, some of the budget sites sell optical acrylic ones. Can probably buy a bag of ten for a few dollars.

That said, aspherics do have some limitations: The light coming out of the LED comes out in a cone that is typically wider than the back of the lens when the lens is at its focal point. This means a lot of light will be lost into the sides of the bezel instead of going out the front. This can result in 50% of the LED lumens being lost.

Another path to consider is moving from LED to low powered lasers instead. Lasers are available widely in R G B colors and it is a lot easier to deal with a couple laser beams than the optics needed to shape the LED beams. This would also provide for the beam to stay relatively the same diameter over a fairly long distance to the object. Optics to combine multiple beams into one are common.

I had thought of that but was unsure if they could be eye safe. It wouldn't be used to examine eyes but I'm pretty paranoid.
That may be a good option.
Thanks