For this purpose, we developed what's known as the mini roll coater.
So it's a drum, where we apply a foil.
It's, yeah the drum circumference is one meter so you have one meter of foil.
And it can be a piece of foil that
has been processed, roll to roll and then when we
reach a certain step it could be the active
layer for instance after having printed the first silver grid.
Printed the second PEDOT, coated the zinc oxide layer, and now we
want to focus on optimizing the ink for the active layer in this process.
So, you could say that the steps leading up to the active layer in
that case, are fully transferred, and fully scaled to a roll to roll process.
But the active layer is not.
So we can cut out meters of foil a meter at a time, put it on the
main roll coater and play with the active ink, and that way we use very little foil.
And we use very little active material when we develop the ink
so that it fits exactly on the larger roll to roll processing platform.
We can then, once we're confident or comfortable with it, we
can try and do, actually, on a full roll to roll machine.
And that way establish this transfer or the final scaling from something that
is nearly a roll to roll processing step to a full roll to roll processing step.
The mini roll coater has the advantage that, that it eliminates a lot of the
sources of error that you have on a, on a large roll to roll processing machine.
As you should, shall see in a while even a small pilot scale or
laboratory scale roll to roll processing machine easily has 30 or 40 rollers on it.
And whenever you roll foil through the machine, even once.
It has to pass all these rollers.
Some of the rollers are touching the back side of the
foil, some of them are touching the front side of the foil.
And the mini roll coater has the advantage that it doesn't touch the front side.
So if a source of error in your process is
that it doesn't handle the front surface, top surface is touched.
You won't see this on the mini roll coater.
So the mini roll coater enables you to do the full layers, or this particular layer
you're interested in, without touching it with anything
else than the application method that you're focusing on.
It could be slot die coating or flexographic printing or something else.