Aspheric Lens Specifications.

[footprintz]

Hello All. i m newbie. need to know something about Aspheric Lens.
I have a supplier of Lens from China. and having good quality lenses also. i have found a lens for my flashlight reflector. The reflector Dia is 52mm.
and lens Dia is also 52mm in width and center thickness is 19mm. And lens material is "borosilicate glass".
My question is.. Does this Lens can work with reflector for tight beam? reflector has very good beam right now. u may see this in my webpage. I dont know how will lens work. can anyone tell me if the reflector can be suitable with reflector? The supplier said he dont know if borosilicate glass can work or not. anybody knows this? attaching image of lens and reflector along.

 

[chef4850]

I have several aspherical light and none of them use a reflector. Not sure if it will affect the beam. I would assume that if none of the other have one there is a reason why. Try it without the reflector. you just want to "project the die". The hot spot will look like a piece of bread. square shape.

 

[jankj]

This should give you a pretty good idea of what the beam from an aspheric + reflector looks like... (from this thread that has some more examples and beamshots).

Just ignore that funky pattern where the spill part of the beam use to be. The hot spot ("LED die image" if you focus properly) will look just the same and will be just as intense as without a reflector. So - it will work, but look weird.

 

[xenonk]

I don't see any reason why a borosilicate glass wouldn't work. The real job is getting the correct focal length for the depth of the reflector.

I have several aspherical light and none of them use a reflector. Not sure if it will affect the beam. I would assume that if none of the other have one there is a reason why.

Using a reflector will preserve some more of the output instead of letting it be absorbed by the head walls, but it will come out as a ring projecting the reflector. I guess it's just a matter of whether or not you want the spill badly enough.

 

[Patriot]

EDIT Thanks footprints for adjusting the pics. :)


With regards to the aspheric, a reflector can be used but due to beam artifacts they're usually not used together. The glass type is fine but
borosilicate glass is slightly less transmissive and so it absorbs a slightly greater percentage of the light source than some other glasses.

 

[footprintz]

Image size edited. Thanks for suggestion.

 

[jahxman]

The experiments I've done with reflectors and Aspherics have made it clear to me that it's best to use one or the other, not both. Both together tends to produce a lot of ugly artifacts in the spill.

The best method appears to be to use two lenses, one to pre-collimate the output from the LED, and the second being the aspheric to focus the pre-collimated light. This puts the maximum of the LED's output into the collimated beam.

Otherwise a single aspheric with no reflector is best.

 

[footprintz]

Hello Mr Jahxman, can you please more elaborate? or if possible give details or example with images. or show lens types and if i use 2 lenses one is asperic and other one? can use with reflector?

 

[Patriot]

footprintz,

The info you're looking for is burried at the beginning of this thread

and somewhere near the end of this thread

Sorry for not having the exact page but you'll eventually come across the image or images.

There may be other examples but this is the thread I know of off hand.

Good luck :)