[no_wizard]

I don’t know that there is any technical reason why e-ink can’t develop a better refresh rate to match what we are used to, at least theoretically. I don’t think its refresh rates are capped in that way.

The real problem is cost of course. Part of that is e-ink is still governed under a patent you must license and pay royalties to if I recall correctly

[ZiiS]

The ink has to actually move; all sorts of physics sets hard caps to the refresh rate. Not saying they won't improve from what we have; but compared to the switch time of an OLED this isn't just lack of investment.

[dirtyid]

Whats the theoretical cap? Gen pop likely can live with 30fps if we eventually get there.

[Brian_K_White]

Eink works by physically moving bits of material around in a viscous liquid. You can refine that (use stronger electric field, stronger reacting pigments, less-viscous fluid, thinner layer for smaller travel distance) but never get around it.

[thelazyone]

That is true, but this doesn't pose a theoretical limit to a 30 fps monitor.

I suspect that the current technology works by "setting" in place whole regions of the screen at once, and that this kind of process is inherently slow. Maybe in a (not so distant) future it'll be possible to have individual pixels changing, in a similar way as an mp4 doesn't update all the image when not necessary.

Or not. So many technologies just embank somewhere and find their niche.

[Brian_K_White]

They do that already, and it results in ghosting and leftover artifacts.

It's all tradeoffs, improving one number only to a limited extent and only at the expense of other numbers. Ie, faster action at the expense of worse image. No free lunch or getting around it by handwaving 'advancement'.

[thelazyone]

If the update was truly pixel based there should be no ghosting/artifact whatsoever. Looks like global refreshes or cleanup are still relevant, while ideally each pixel could be completely independent.

Trade-offs are a problem, but in this case i don't see any physical reason for this to be a theoretical trade-off. More like a limit of the current technology.

[arp242]

It is pixel-based, it just doesn't result in perfect updates. I'm not entirely sure why this is the case: maybe the power is too low (as a trade-off between speed and accuracy), maybe clear a cell affects neighbouring cells, or maybe something else.

E-ink displays are hardly new and lots of people have been thinking about/working on the slow refresh rates for over 2 decades. Do you really think that anything you can come up with on HN in 5 minutes without any knowledge of the tech is something people hadn't thought of before?

[thelazyone]

There's a big difference between having a solution and point out that there is no theoretical hard trade-off. ^^"

[mdp2021]

> If the update was truly pixel based there should be no

Why? Nobody said that the cell is "reset". The cell is modified. The resulting state depends on the former state. This causes ghosting.

To achieve what you are suggesting, the procedure would be e.g. to first set the pixel black, then white (reset to a base state), then the greyscale value of the intended content. This would slow down rendering dramatically, and make regions flicker.

And, note, this may be something that some "EPD waveforms" do - but there are tradeoffs... E.g. Fast? Ok, lose the greyscales. Detailed? Ok, get lots of flashing at update. Mid-way? Ok get some degree of ghosting.

[thelazyone]

That's a fair point, well made. In that case --- yeah, we just have to wait and hope for better solutions/materials for our screens!

[Brian_K_White]

It is pixel based logically, which comes out only imperfectly physically. Believe what you will.

[thelazyone]

Yeah, the other replies were pretty convincing about that point.

[mdp2021]

> it'll be possible to have individual pixels changing

EPD displays already have that capability.

When you modify the dots you use a modality that is sensitive to former states. What happens in full-screen refresh is a cleanup to redraw on the best former state for the cleanest output.

[thelazyone]

Even local refreshes however are somehow rectangle-based, no?

Which means that the resetting operation kinda works globally anyways, masking out everything between the xmin, xmax and ymin, ymax.

I'm really speculating here, but this was my impression every time I saw individual areas changing without a gobal refresh.

[ambyra]

I wonder if it would be possible to layer screens to double refresh rate.

[braunboffel]

> e-ink is still governed under a patent you must license and pay royalties to if I recall correctly

Recall correctly meaning you were involved and have direct knowledge or meaning you read it as an unsubstantiated comment somewhere here?

[Qwertious]

>The real problem is cost of course. Part of that is e-ink is still governed under a patent you must license and pay royalties to if I recall correctly

This is a common myth that's echoed without a source. It's not patent, it's scale - there are literally 6 billion (LCD) smartphone users out in the world (it might be up to 7B by now), with lots of those users owning multiple smartphones. And of course, there are loads of other devices with LCDs: laptops, desktop monitors, TVs, self-checkout kiosks at supermarkets, smartwatches, tablets, LCDs on a fridge for some reason, etc etc etc.

E-ink is orders of magnitude lower in production scale, without a clear way of expanding the market beyond just ereaders/enotes (which are a luxury; you can read ebooks on a smartphone/tablet and most people own one of those already), and possibly supermarket smart-pricetags.

So, does that mean E-ink faces zero competition? No! DES screens are competing against e-ink with their cofferdam tech (where instead of sprinkling on microcapsules, they capsule structure is built directly onto the substrate; it reduces thickness and theoretically increases pixel density, but loses the "grain" effect of E-Ink's MED in favor of a less-aesthetic regular grid shape).

If E-Ink could improve refresh rates then they absolutely would - it's the most visible feature they could possibly add, and is directly applicable to e-readers, which are currently their biggest market. And their biggest buyer is Amazon, who have poured a whole lot of money into the tech (and who sell Kindles at-cost or below) and if it really were patents blocking faster-refreshing screens then Amazon would just buy E-Ink, outright. It's not new - look up LiquaVista; they were bought up by Amazon, Amazon's not afraid to buy up companies. Plus, E-Ink still have to compete against second-hand e-readers they've already sold; there are E-readers from 2012 that will read a .epub just fine, and that's all you really need for an e-reader.

If you're wondering why Amazon killed LiquaVista, BTW, apparently it's because shrinking the pixels horizontally causes a chromatic aberration effect when the vertical color-layers are viewed from an angle, so shrinking the pixels horizontally also requires shrinking them vertically, which makes it extremely difficult to manufacture the pixels without them leaking and causing a terribly low yield rate. Also it didn't help that a bunch of the original company's VC raising was done just before 2008.