Well, not really sunglasses, but rather clip-on shades for my 3D-printed glasses
But here's the thing: they're FULLY 3D-printed. The "lenses" are in fact the finest and thinnest mesh I could print with our printer - basically one 0.1mm layer of 0.4mm lines spaced 0.4mm running horizontally, and an identical layer of lines running vertically right on top of it.
Is it perfect? No. The image through it is kind of "pixelated" But it's surprisingly acceptable. It looks like this when looking through them:
In real-life, it's quite a bit darker than this. But the photo shows fairly accurately how it looks like seeing through them.
It works because the mesh is very close to the eyes and totally out of focus. And although it's not optical-grade, the price is unbeatable 🙂
If you want to try printing it yourself, the model is here. It's meant to be printed with a 0.4mm nozzle and a 0.1mm layer height - including the first one.
Double-check how the slicer slices the first two layers, where the mesh lives, because it easily tends to "simplify" the lines by not printing them, which is obviously not what you want.
EDIT: as others have pointed out in this thread, don't use these shades as actual sunglasses without sticking some UV filter over the mesh on the inside. They're not eye-safe as-is. I made them more for the challenge of making them than anything else.
Yes, it will be 50% (looks like half mesh) darker to visible light so your pupils will dilate and allow even more UV light in than if you didn't wear them. What isn't mesh lets UV straight in. Whereas sunglasses block 100%.
I'd call those Cataract Glasses instead of sunglasses.
Wouldn't it block 50% of all light, UV included?
Pla plastic typical in 3d printing lets 95% of UV-C light through. So it looks dark to your eyes but is transparent in the UV spectrum.
https://www.mdpi.com/2504-477X/7/10/410#:~:text=The%20optical%20resistance%20of%20PLA,of%20ultraviolet%20light%20is%20transmitted.
Also a pupil dilated has an area of 12 mm^2. A contracted pupil has an area of 3 mm^2.
So it's 4x more uv light coming in than if you didn't wear them.
These sunglasses are far more dangerous than not wearing sunglasses.
75% actually. Each layer lets half the light thru, so it lets half of half thru in total.
But yeah, like others said, that doesn't make it safe.
Pla is transparent to UV-C. (The cancer causing UV). So your sunglasses trick your eyes into dilating and allowing more UV in.
Yes. This isn't as bad as the dark lenses without UV filtering that people are throwing around.
But it doesn't reduce the UV incidence either.