Diffusion Techniques Testing - Various Methods

[quote=Boaz]

This?

-Garry

My favorite diffuser is a frosted lens. Not spray-on frosting, but a genuinely frosted piece of glass like what the Zebralight ā€˜Fā€™ models use. It provides a basically flawless beam. DC-Fix, OTOH, has lots of little artifacts in the beam. Itā€™s not very noticeable most of the time, but if you rotate the light along its beam axis the artifacts will be visible while theyā€™re spinning.

This thread inspired me to do something Iā€™ve been postponing for a good while: diffuse a headlamp, the $7 one that was a big hit here on the forum. Iā€™ve seen the threads on CPF of someone selling by the sheet and shipping to me killed it. It so happens that my local Dedeman has DC Fix in stock and I picked up a square meter for about 5$, that should suffice for now. Iā€™ve cut it to dimensions and stuck it on the inside of the glass lens to keep a minimum of waterproofing. Below is a beamshot with one headlamp in its original state and one with dc fix applied. Much nicer light to work with in close proximity.


FWIW, I took some comparison shots of two ZL SC52 lights, one stock and the other with DC-Fix Sand on the lens. Itā€™s hard to show the different well in photos due to lack of sufficient color depth, but with a few exposures it seems okay. Here are the results:




I also compared my ā€œbrass beautyā€ light with DC-Fix against a wide-beam SK68, to show why I prefer the brass light for biking. Itā€™s much wider and smoother, and the center of the beam is still brighter than the edges so it does a better job providing even illumination out into the distance. Plus, the 1x18650 light can go much brighter and lasts longer per charge. I had to turn it down pretty far to make a fair comparison in the photo.

I'm very interested in this, but can't see the pictures :(

I recently bought an expensive aspheric lens from Thorlabs that had been treated with 1500 grit to act as a diffuser. It is really a nice beam, but does not throw as far as I had hoped with the diffuser treatment. I just got a couple of cheaper aspherics from china and plan to try to lightly treat it with some 2000 grit to see how that does.

Just curious, but can you post a link(s) to beamshots which approximate what you are trying to do? Iā€™m just not familiar with the whole diffused aspheric concept at all.

Sorry, pics will be back on the 24th. Until then there is a link in the OP to the photo gallery.

-Garry

This happened to me too last week.

[/quote] Just curious, but can you post a link(s) to beamshots which approximate what you are trying to do? I'm just not familiar with the whole diffused aspheric concept at all. [/quote]


I don't have any beam shots and the light is at work right now. I'll try to remember to get some soon.


The concept is simple though. Thor Labs just took 1500 grit sandpaper and roughened up the flat surface of the aspheric. They went a little too far or rough for what I wanted, but it makes for a very nice beam profile.

Hmm . . . Can I do that with a regular glass lens? Another technique to test? I'm going to have to order more lenses!

-Garry

I believe so. I'm going to try it out with one of the two aspherics that I just got in the mail. I'll let you know how it goes. I'm just going to use plain super fine grit sand paper on a granite surface

It may even be possible to do a hybrid lens using a fine grit and a small media blaster. For instance you could treat the outer portion of the lens with the grit and leave the center clear. That's the best way I've come up with to get rid of the square LED die image for aspheric lenses while retaining most of their throw.

Etching Cream.

If you want to keep the hot spot and just have wider spill leave a narrow ring clean right at the edge near the bezil, that is where the hotspot is created, and everything else will get diffused

Interesting! I'll see if I can try that with DC Fix. I'm pretty sure I'm going to order new lenses though and that means I'll have snow on the ground by the time I'm ready for beamshots!

-Garry

just joined up. hobby cyclist needs lights and cant pay top dollar so happy going diy!

since I also bought a pair of ebay china magicshine clone and then decided to look how to improve the beam pattern, I also sourced and fitted the wide angle lens to my 2 bar mount and a google of frosting lens found me here, at an active thread, not something 3-10 years old haha

greetings to all, :slight_smile:

Welcome!

Welcome to BLF! Glad we could help!

-Garry

Beware, there is a disease called ā€œflashaholismā€ that is running rampant here. If you stick around, you will be infected by the disease. Then, you will not be able to stop buying more and more flashlights until you learn to build them yourself. Then you wonā€™t be able to stop buying parts for flashlights! You have been warned! Welcome to BLF! :bigsmile:

Iā€™m a little late to the party, but sometimes the symptoms to manifest differently: Once infected you may start purchasing parts before learning to build lights. Youā€™ll still have an empty wallet, but in that case you donā€™t even get any fancy lights (until the disease progresses to stage 2).

Great experimente indeed, thanks for taking the time and sharing it with us.