Perfect DIY low cost diffuser lens

[Luminescent]

I have a Mini-Maglight 2AA light with an old style Terralux 'side emitter' luxeon LED emitter drop-in.

While this combination is intended to retain the Maglights variable focus ability, the beam pattern really sucks.

I have tried a number of diffuser materials to improve the beam pattern including the diamond prism patterned material used on commercial fluorescent light fixtures, but most materials either caused too much light loss or just did not do enough to smooth out the beam.

I have found what seems to be the absolutely PERFECT material.

I think this may have been suggested here on CPF before, but if so, let me add a +1 recommendation for using the bottom half of the clear type half-height compact CD/DVD jewel cases with the textured 'foggy' defused pattern on the bottom plastic material.

These compact jewel cases come in a multi-color assortment that can be found at most department stores and office supply outlets, and the clear case with the defused pattern translucent bottom is PERFECT for creating flashlight diffuser lenses.

I just removed the plastic lens from my Maglight 2AA and replaced it with a matching lens cut from the translucent bottom of one of the clear CD/DVD cases (put the shiny non-textured side facing 'out' and the textured side 'in' for best seal with the bezel o-ring).

Any diffuser will tend to kill the throw, but this stuff seems to have a lot less loss than even the 'purpose-built' specialized diamond-pattern diffuser material I was previously using, and it gives a beautiful floody beam which will light up moderately large area very nicely.

The light maintains a nice bright (but now perfectly smooth), one foot hot-spot at three feet at tightest focus, and can be defocused to double or triple that spot size before the 'hole in the middle' effect starts to rear it's ugly head.

Stippling the reflector would also probably work, but would almost certainly have more loss and provide less throw than this arrangement, and this modification is a lot easier to reverse (just replace the original clear lens if you decide you don't like the effect).

There have been a number of threads looking for a nice close-in floody light for reading, and I have to say that the Terralux drop-in equipped Mini-Mag with the main lens replaced with a diffuser lens fabricated from one of these clear CD/DVD cases is absolutely perfect for that purpose.

 

[Kilovolt]

Interesting, thanks.

What tool do you use to obtain a clean cut?

 

[mmmflashlights]

I have hundreds of these slim jewel cases, unfortunately only one of them is a frosted translucent one that I can recall. I couldn't find it to try, but I did have basically the exact same material on another piece of plastic, just a little thicker. It does work nicely to diffuse the light, just holding it in front of the lens the light is spread out wider and giving a smooth flood beam without cutting down on output as much as a lot of other things I've tried. So thanks for the idea.

 

[Luminescent]

I have hundreds of these slim jewel cases, unfortunately only one of them is a frosted translucent one that I can recall. I couldn't find it to try, but I did have basically the exact same material on another piece of plastic, just a little thicker. It does work nicely to diffuse the light, just holding it in front of the lens the light is spread out wider and giving a smooth flood beam without cutting down on output as much as a lot of other things I've tried. So thanks for the idea.

I hesitated to use the 'translucent' description because for some folks it kind of implies that the plastic has a milky white filler, where the stuff I am talking about is absolutely crystal clear and has a very fine grain random surface texture on one side that does the job of defusing the light even though the plastic is perfectly clear.

Sounds like you figured out the right stuff anyway.

On the question of how I cut the material, I drew a line around the old lens with a fine point marker to mark the material, and then used a 1/8 inch carbide router bit from harbor freight in a battery powered dremel tool to very carefully cut up to the line. I used my battery powered dremel because the main problem with a higher speed tool is that it tends to get out of control and cut inside the line.


Then I finished up with a file around the edge to get a nice clean smooth edge.

I was careful not to scratch up the smooth shinny side since that's the side should face out for the best seal with the maglight's front bezel o-ring. The plastic seems to be acrylic based and is at least as scratch resistant and durable as the original lens (it's also a perfect match thickness wise).


I'll try to post a picture later, because aside from how this stuff works, it also looks really nice aesthetically and gives the lens a incredibly cool almost 3D look when the light is on.

 

[mmmflashlights]

You are right that translucent may throw some people off, though it's not transparent so I think it is a true description. It could be compared to a scaled down version of what you see on many shower doors, where it is letting most of the light pass through but is scattering that light.

I have some cases that are translucent blue, green, pink, and sort of a amber yellow. While the yelllow cuts down on output quite a bit, I may cut up one of those to see how it does for retaining night vision.

 

[Luminescent]

I have some cases that are translucent blue, green, pink, and sort of a amber yellow. While the yelllow cuts down on output quite a bit, I may cut up one of those to see how it does for retaining night vision.

Early on the half height jewel boxes were all just black on the bottom and crystal clear on top. Later they introduced tinted sets, and some early color sets only included tinted boxes in various colors, but the last few tinted sets I purchased all came with some clear cases with crystal clear tops and textured clear bottoms (which is what makes the great diffuser).

I have also seen some sets of half height jewel cases for sale which ALL seemed to be clear, but I am not sure if they had the same textured bottom material or not (I think they may have been just crystal clear on both top and bottom).

Some of my newer lights like the jetbeam C-LE with the textured orange peel reflector have spoiled me I'm afraid, and I am now quite fussy about beam quality, but this simple diffuser mod has given my little Teralux maglight dropin a new lease on life.

 

[redledz]

I found the same thing with some old pocket cdrs I had. I cut out a circle with a dremel and put it in my dmini. Very nice flood indeed.

 

[marpilli]

I wanted to stop in and say "thank you" for this idea! I ended up building a diffuser lens for my Convoy S3 and I'm very happy with the results. I went as far as to gather up all of the half-height CD cases in the house and stash them in a project box in the garage for future use.