Original linked MIT article[1] has a little better explanation of how this light beam is controlled.
The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.
the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.
A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.
The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.
From what I got, it replaces the printer head plus the entire positioning assembly of the head. It's still not the entire printer, but it would massively simplify the mechanical construction.
It controls the phase of the light as well as the intensity, which is novel compared to a galvo. The paper suggested holographic curing, which sounds like a joke but it seems is a real thing where they use three photons to cure and controlling phase lets them do that somehow. But it's only kind of mentioned offhand, so I'm not sure how serious they are about it.
They have a novel photoinitiator which requires light from two different wavelengths to initiate polymerization. They currently scan a plane of laser light through a static resin vat while projecting a 2D video through the same vat.
So it's a non-mechanical galvanometer replacement for steering a laser. Very cool, but that's like one small part of a 3D printer. Also wonder if it can steer in 2 dimensions, or if you need 2 of these, or is that not possible? Can it be used for ILDA laser shows?
The form factor here is cool, but as someone whose been resin printing a bunch lately, the pitch to carry it around in your pocket sounds questionable.
1. Where are you going to store the resin? It isn't good to touch it. Are they also expecting people to carry around somewhat toxic resin in their other pocket and then make a little puddle on the ground to print? Resin printing is messy and cleaning is hard. Make sure to carry isopropyl alcohol in your other pocket.
2. It produces toxic fumes while printing that you need to exhaust. So you at least need a mask.
3. It takes hours to print on a large machine: you need a model file, to edit the model to print in resin well and then the actual print can be multiple hours long. Not to mention multiple print failures which is often the case.
Everything mentioned about the surgical application sounds possible today, but it's still not fast enough or reliable enough in that scenario. Also... Resin isn't that strong, you want to graft it to a bone, what?
Raw materials aside, a tiny printer can go places a large printer cannot. Space? Deep sea? Inside other machines? Or on the tip of a robotic arm to do print little parts right onto their permanent place like a spider placing silk? Who knows!? 99% sure the "in your pocket" statement is more like "smaller than a breadbox", as in, it's plain-as-day comparisons of size, not use.
The size of the printing mechanism is an innovation for sure, but I think after you add up all the other components to make a functioning printer you end up at nearly the same size: a resin vat, space to print, various leveling mechanisms, filters, UV light shield etc - the form factor doesn't really change all that much.
If you think 3D printing is always going to be on a flat bed of the same size using the same amounts of material, then yeah, minimizing the printing mechanism sure seems like a non-necessary improvement. But that's not the intended use case anyway. It can only print small things. Maybe it can add tiny details or structures to large prints though
Hmmmm interesting. I can see a use case for like a drone or small robot to have one of these attached to add details all over the place. Ok you've convinced me it's cool lol
Imagine the equivalent of endoscopy: being able to insert a small tube inside of an object and print structures larger than the tube inside of them.
Obviously, that requires a lot more than just this, but it's intriguing to think about being able to perform internal repairs of nearly-sealed objects.
Or print a kitten inside a bottle, for those old enough to catch the bonsai kitten reference. ;)
Resin isn't toxic. The problem is that resin can cure under your skin and the only way to get rid of the resin is for your immune system to do it. So people develop allergies against cured resin, which tends to cause more damage than the resin itself. Even after you have developed a resin allergy, there is generally no long term damage as long as you stay away from it and don't trigger your allergy.
AIUI, resin 3d printers currently either use a UV laser and a set of galvos to steer it across the build plate, or a bright UV LED and an LCD to selectively admit and block light to various parts of the plate. The laser approach is higher performance but more fiddly and expensive, while the LCD approach is simpler to set up but has a shorter service life (due to UV degradation of the LCD) and produces lower light intensities at the build plate.
I have often wondered why nobody uses the DMD approach[1] common to digital laser projectors. This sounds something like that, albeit with the mirrors replaced with this LCD magic.
This is cool but the miniaturization and integration of the optics doesn’t result in a functioning printer. You still need the bath of resin and the printer. The headline is like saying you’d have a coin sized printer if you only focus on an inkjet head.
What is neat is that this could potentially project a configurable hologram!
You could partially cure the bottom layer, pull that layer up, then finish curing that layer while forming the next layer. This could significantly accelerate the print speed!
