Hi!
Has anyone printed a lens, or an lens array, or a fresnel lens?
It works?
thanks in advance.
I’ve been party to some attempts. We’ve had absolutely no luck with fresnels, but have produced some “distinctly lens like” (functional, but terrible optical qualities) things by printing lens-shaped blanks in clear PLA, then polishing by various means - haven’t been sharing much about that because the primary individual involved is hoping to get a publication out of it.
I read recently on G+ about a new optically clear printable plastic… but I don’t remember who posted it or what the name of the plastic was. It’ll take a bit to find…
Here we go: https://plus.google.com/u/0/104199731463622588564/posts/4nM1SWymnTd
It was a post in this community too!
Taulman t-glase: http://www.taulman3d.com/news.html
We’re keeping an eye on it, but the limiting factors seem to be more about being able to lay it down without visible internal structure and smooth the surface without discoloring or altering the shape, rather than immediate optical properties of the material.
If you want a clear plastic that can be smoothed really well, try MABS. It’s a hybrid of ABS and acrylic that is clear and smooths beautifully in an acetone vapor bath. It tends to come out kinda white in prints, but keeping the whole print at a higher temperature and eliminating air pockets should result in pretty good clarity.
Sound Lens —
This post reminded me of something I thought of a while back when looking at the intricate structure of a high end (I think it was a Bose) speaker.
I would guess it would be possible to design and print speakers for specific room configurations.
Could be an interesting business to get into if that sort of thing floats your boat because I recall seeing speakers in a specialist audio shop with price tags ranging from 1000 to 4,000 pounds sterling.
one more question.
And a printed parabolic mirror? or accurate polyhedric mirror?
I wouldn’t think of printing as the go-to method for making structured mirrors, getting a good reflective finish/surface would be a PITA.
Huh, so the “Clear ABS” filament a few of the vendors offer was actually MABS, that explains how it works and makes it more interesting. So far most of the lens experiments have been in MatterHackers Clear PLA, which is a little drippy and difficult to work with due to lack of dopants, but hasn’t been a major obstacle.
Unless your printer resolution is fined than the wavelengths of visible light, no. Now, you might be able to print, say, ‘Microwave’ lenses/metamaterials by using metal doped plastics.
@Daniel_Joyce I think you might be a little pessimistic in the resolution needed. We’ve been making lenses for a few centuries now, and I’m pretty sure Galileo couldn’t machine glass to 200nm tolerances. Many lenses today are made by injection molded plastic. I THINK that process is only good to about a thou, which is a little better than rep-raps are doing right now, but not a lot better. CNCs like the shapeoko are not hugely different than a reprap and are doing that, for example.
Actually, you can hand machine lenses to quite high tolerances, within a wavelength of light, using some cute tricks to check your work. The problem with reprap is the ‘rope’ striated texture, unless you are willing to grind, and the issue of air or bubbles in the PET filament.
The majority of plastic injection molded plastic lenses aren’t useful in scopes, beyond say children’s toys. I suspect the lens in CD burners may be injection molded, but those are small molds where spending a lot of time to get it right is not cost prohibitive.
Using this phenomena, it is quite possible to hand polish a lens with incredible tolerances.