Sold/Expired Concave Lens for Small Flashlight

[Quantumstate]

About to buy a Fenix L0D CE flashlight, but a spot of light doesn't suit. Need a more spread beam.

So looking to replace the lens with a one-sided concave one. ~12mm, say about 4 diopter. I may also be buying a L1D CE, and so will need a concave lens for that as well, ~18mm.

If it is not possible to remove the lens due to the construction of the head, I'd glue the concave over the factory lens.

Does anyone know of a good source for optical grade lenses? Ideally it should have an anti-reflective coating, and be of high-grade media like sapphire, but this isn't critical. Also, recommendations for glue? Cyanoacrylate?

 

[nerdgineer]

Re: Convex Lens for Small Flashlight

Don't have a measurement, but how about the lens off one of the new model Dorcy 1AAA's? It would have to be cut out of the plastic piece of which it is a part, but it might work.

 

[Quantumstate]

Any idea whether it's glass? Usually it's not, on flashlights.

Needs to be glass, due to the heat in this flamethrower.

 

[Raybo]

Here is an 18.5mm convex lens

http://www.surplusshed.com/pages/item/pl1007.html

 

[Quantumstate]

Thanks.

They also have a concave one. Doesn't say how thick it is, nor whether it's glass or not. At that price, gotta be glass tho.

 

[Raybo]

BK7 is crown glass.

I have ordered several lenses from them and they are top notch.

Ray

 

[flex76italy]

Hi, the part number of this item is 01 LPX 049, see the pdf here

 

[Quantumstate]

Good to know Raybo, thanks.

Flex76 thanks, but that lens is convex. I must have concave, as I need to spread the light. I want something more like a floodlight, not a spotlight. They do have concaves on that site apparently. Looks like I've found my source.

 

[bombelman]

Hey, nice thread, great sites too !

I'm looking for domed-lenses, which do not affect the beam, or which could tighten the beam, not give it a flood.

I like the KL1 lens, it's domed, and I use it for my A1 head also.
It does not affect the beam, it's about 2~3mm thick...
(here: http://www.candlepowerforums.com/vb/showthread.php?t=152369)

What do I need to look for ?

 

[Quantumstate]

A domed lens will always affect the beam. By 'domed' it sounds like you mean a 'plano-convex', which is flat on one side and positive domed on the other. Plano-convex and biconvex (domed both sides) will always narrow the beam.

With the reflector and LED you already have, with this lens you may end up with a point of light that will start paper on fire. So you'd better try your setup and see how you like just the straight beam first. If you still want a domed lens, start with the site Raybo gave us, and search for your diameter in 'plano-convex'.

Seems like you're running some hot lamps, so the lens you put in there must be glass. Most glass lenses won't reduce the light output noticeably.

 

[bombelman]

:lolsign:
I'm runnin' Cree and SSC emitters, some overdriven.
I have 2 KL2 lenses, both look like the "Meniscus" lens on the link you provided,
meaning they have the curve in the same direction.

What I can tell you from this lens, it does not affect the beam, as I just did
a test to confirm. At least, it is not noticeable at all.

The lens is 3mm thick and 22mm in OD. I think it's hard, it came from a KL1 head.

What I can tell you, is that if I take off my glasses and look into the lens,
I see just as good as with my glasses. (-3)....

Cheers !

 

[Quantumstate]

Oh, OK. When you say domed, you mean meniscus.

When the back and front of the lens have exactly the same curvature, there is no change in the light, as you say.

 

[Raybo]

:lolsign:
I'm runnin' Cree and SSC emitters, some overdriven.
I have 2 KL2 lenses, both look like the "Meniscus" lens on the link you provided,
meaning they have the curve in the same direction.

What I can tell you from this lens, it does not affect the beam, as I just did
a test to confirm. At least, it is not noticeable at all.

The lens is 3mm thick and 22mm in OD. I think it's hard, it came from a KL1 head.

What I can tell you, is that if I take off my glasses and look into the lens,
I see just as good as with my glasses. (-3)....

Cheers !

bombleman,

If you want to run your light without a reflector you could try a lens with a slight aspherical curve, the beam might not be as pretty as a reflector but you will get some good throw.

Ray

 

[bombelman]

No, I really like the reflector and dislike optics.

I just like the 3mm thick domed lens from the KL1, I want to try it in different lights too.

 

[Quantumstate]

Found the answer. Don Mc tells me about a diffusion grating from Luminit. Very efficient, although I may choose their fresnel instead.

 

[Quantumstate]

Whups, they're $175 for a 3/4" disc.