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It's possible to refresh e-ink without a global flash if you are careful and have a clever controller. I don't think this video directly addresses this but it gives a good overview on the problem space https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ jrockway

Yeah, I've seen Ben's video but used a different controller and didn't get very good results with my (very cursory) tweaks to the various tables that controlled the refresh.

Here is a good video on that subject:

https://www.youtube.com/watch?v=MsbiO8EAsGw

Colored e-ink displays are discussed at around 8:00 in this video; there are probably better sources, but this is the one I'm familiar with, so I figured I'd link it: https://www.youtube.com/watch?v=MsbiO8EAsGw

The microcapsules are not individually wired up to anything, so I don't think it's feasible to make each color channel independently addressable. Instead, a grid of wires behind the capsules are either positively or negatively charged, in order to attract or repel the charged colored particles in each capsule. There are only 2 charges, but by using different sizes of particles for different colors, you can finagle it so that the color you want ends up on top.

If they could address capsules individually, that would also increase the possible resolution of a black-and-white display; they'd do it if they could. But since the mechanism is about attracting and repelling charged particles, there's probably a pretty hard limit on how much you can increase the resolution before there is interference between neighboring pixels.

For single or double-color displays, you can do pretty decently. This Applied Sciences video on YT goes over what's possible. https://www.youtube.com/watch?v=MsbiO8EAsGw

Great video on these sorts of displays, what they're capable of, and perhaps some inspiration for any hobby projects: https://www.youtube.com/watch?v=MsbiO8EAsGw&t=617s

Turns out that e-ink displays typically don't mix colors this way. In order to get multiple colors in a single display, they use sort of colored-balls of various densities suspended in a fluid. Then, using the known viscosities of the fluid in the capsules, they can vary the charge of the electrodes very quickly to sort of _drag_ a color up to the top.

But when you do this, you're dragging a _single_ color.

_All_ the colors are in the capsule, but you can only truly pull a single one at a time, a true pigment-like mixing isn't possible. If you pull the Cyan up, you're necessarily losing the Magenta, for example.

If you had a high enough resolution addressable grid, you might be able to put the pixels close enough that you couldn't tell, but you'd still be basically doing sub-pixel color at that point, not truly mixing the various colors at the base level.

Maybe there are other e-ink displays doing something else, but all the ones I've seen are doing some form of this approach.

Here's a fascinating video on how these displays work, and how you can modify the firmware of the driver to get faster refresh rates (with an increased risk of burn-in). https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ vikramkr

An area of research I've heard a bit about for next gen e-paper displays is to use electrowetting[1] which is a different approach that looks intersting

[1]https://en.wikipedia.org/wiki/Electrowetting#Applications

⬐ sparker72678

Oh, fascinating! This looks really interesting!

yeah I believe that was the only option for older / cheaper displays. I recently got a kindle for a present and notice that when it can, it will try to refresh the screen as little as possible.

For example, when you press the top of the screen to bring up the settings, only the top cycles, and then the same when you tap below to get rid of the settings.

To that end, I would be interested in watching some high-speed camera footage of the displays just to see the gears turn. I’ll have a look round and edit this comment if I find any.

e: found one.

https://youtu.be/xc6cFkCr1-8

also a video from an engineering channel that normally gives good insight into these things, I have watched it yet so it may not be great, but Applied Engineering normally brings some interesting material.

https://youtu.be/MsbiO8EAsGw

I didn't design these things, so all I know is that the datasheet says the lifetime will be reduced if you update it more than once every five minutes. A clock with a minutes display exceeds that by 5x.

(And indeed, the display I used did break! I have no idea why, but it just stopped updating one day.)

Ben explains some of the constants that can be tweaked here: https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ brettcvz

I can provide some context here - from my experimentation, after 10 partial updates the contrast is notably worse, but doing a full screen refresh resets things sufficiently that the screen looks sharp again.

To reduce degradations further, whenever UpNext boots it does a cycle of 10 full screen refreshes - overkill certainly, but I think of this as the “cleaning cycle.” If the screen ever starts to fade, I power cycle it, and it’s fine for a long time.

I’ve been running it continuously like this for 2 years now, and while the screen is a bit less sharp than it was originally, it’s still in good shape - the photos in the article are from this week.

⬐ blueboo

Maybe it can be incorporated into the design: refresh as a kind of 5m warning before your next meeting. I’ve certainly enough meetings not to exhaust ten refreshes before the next head’s up flash...

I don't think they are incapable, they are actively hiding information. Ben Krasnow had to reverse engineer a screen to figure out how to better refresh it.

https://www.youtube.com/watch?v=MsbiO8EAsGw

Eink could have changed the world, yet the only eink display I and many people have it our kindle.

⬐ TuringTest

That screen is terribly slow, even by e-ink standars. "Canvas" displays, developed by reMarkable and commercialized by Onyx, have a minimum lag of about 25ms (for writing) and a rendering mode call "A2" that makes it user interaction quite fast for e-ink,[1] serviceable even for watching video [2].

[1] https://www.youtube.com/watch?v=xeUCFAU4QGU

[2] https://www.youtube.com/watch?v=W4VSGgnQD2I

⬐ ncr100

Worse, the video in the article appears to be sped up.

⬐ jmiserez

IIRC Canvas displays were not developed by reMarkable, it just uses one. But one of the key selling points was that the reMarkable didn't use the vendor display driver for that Canvas display, but instead they wrote a faster one. I have some Canvas-based devices and the screen lag varies quite a bit (the reMarkable screen is faster).

⬐ TuringTest

As I understand it, reMarkable claims[1] to have developed CANVAS from the ground-up on top of Carta technology, in close collaboration with E Ink. It may be as you say and they developed just the drivers, but I believe from their press releases that they are responsible for some breakthrough detail to accelerate refresh, that E Ink didn't think was possible (something to do with a waveform transmission signal to transfer pixels to the screen).

They were the first to build the technology to bring refresh times for writing near the 50ms mark, and hold the patent about it (AFAIK they license this patent to other builders who use Canvas).

[1] https://support.remarkable.com/hc/en-us/articles/36000264751...

⬐ jmiserez

Ah yes I mixed up CANVAS vs. CARTA! So my other devices actually have non-CANVAS e-Ink Carta displays.

⬐ TuringTest

I own a reMarkable and a Boox Nova Pro with CANVAS, writing speed is the same but reMarkable's software and feel is definitely better (though I suspect a matte screen protector on the Boox would make the drag feel almost the same).

My understanding of electronic paper displays is almost entirely founded in the great Applied Science[0] video about it.

I have to assume that the way that a full color electronic paper display is done would be vastly different than the method that the 3 color displays work. Anyone have any insight into this?

[0] https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ RL_Quine

The way it's updating here, along with the description, give a good idea.

https://www.youtube.com/watch?v=tVANwwXtHEI

I don't think so. It's easy to "paint" over white because that's the base color of the medium, but "painting" over another color means you have to clear it first.

https://www.youtube.com/watch?v=MsbiO8EAsGw

I built an e-ink clock recently. E-ink has two downsides; the datasheet says that the display will be damaged if it's refreshed more than every 3 minutes (I ignore that and refresh it every minute, so we'll see if it lasts) and the black/white/black refresh cycle is very visually distracting. Having that thing in the field of view just doesn't work.

Both of these issues can be gotten around with a different refresh algorithm, but of course the datasheet doesn't include any of them. The vendors regard their refresh logic as proprietary and so you have to spend months trying to figure out what will work, like this: https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ godelski

I've been thinking about doing a similar project for fun. How long have you had the clock? I'd be really curious how hard that 1 minute refresh rate is on the screen. I have a Kindle and I definitely read more than a page a minute (especially on that small screen) and haven't noticed any problems. But a clock is more consistent and constant.

As for a watch, I could see getting notifications once a minute being fine.

⬐ jrockway

A couple months. No side effects at all so far.

When developing this, it obviously refreshed much more than once a minute. Nothing ever led me to believe anything bad was happening. No burn in, no artifacts, no weird behavior at all.

I think the datasheet is being super ultra mega conservative, designed to cover the worst possible unit that they would let past QC being put in a product that would cost billions of dollars to recall. If you got an average unit and you're making one of these things.... you can probably refresh it in a loop for decades and never have a problem. I wouldn't bet billions on it, but I will bet $20 on it.

Ben Krasnow (Applied Science on YouTube) did some research into driving e-Ink displays, and he made some similar observations:

> All of the lookup table information has been removed from this datasheet, because the industry thrives on secrecy or something

Highly recommended, as usual for him it's a great video/write-up:

* https://www.youtube.com/watch?v=MsbiO8EAsGw

* http://benkrasnow.blogspot.com/2017/10/fast-partial-refresh-...

⬐ therein

Yeah, his series is really great and it made me realize the FW flashed on these CARTA panels are actually nothing but the raw waveforms themselves.

One thing that I want to note is that while their documentation might be closely guarded secret, the actual waveforms are actually available out in the open.

For instance here are the raw waveforms for one of the latest Carta generation e-paper panel:

https://github.com/canselcik/libremarkable/blob/master/refer...

  ~ hexdump -C epdc_ES103CS1.fw | head -10
  00000000  34 88 c4 7c 01 2d 01 00  dd 09 00 00 07 06 a4 00  |4..|.-..........|
  00000010  03 58 21 1d 3c ca 01 85  02 00 00 00 40 00 00 fe  |.X!.<.......@...|
  00000020  47 00 00 01 00 04 0d 00  ff fc 00 00 00 00 00 54  |G..............T|
  00000030  00 03 06 09 0c 0f 12 15  18 1b 1e 21 26 2b 30 28  |...........!&+0(|
  00000040  00 00 00 00 00 00 00 08  3e 05 00 00 00 00 00 e8  |........>.......|
  00000050  cb 06 00 00 00 00 00 c8  8d 0a 00 00 00 00 00 a8  |................|
  00000060  4f 0e 00 00 00 00 00 98  00 00 00 00 00 00 00 a0  |O...............|
  00000070  65 00 00 00 00 00 00 a8  bc 00 00 00 00 00 00 b0  |e...............|
  00000080  0b 01 00 00 00 00 00 b8  5a 01 00 00 00 00 00 c0  |........Z.......|
  00000090  aa 01 00 00 00 00 00 c8  31 02 00 00 00 00 00 d0  |........1.......|

Relevant: https://youtu.be/MsbiO8EAsGw

⬐ None

None

⬐ aphextron

Video capable (>30hz) color e-ink displays are on the way too https://www.youtube.com/watch?v=pqn2650CJYc

⬐ ernesth

Another video: https://www.youtube.com/watch?v=24srQXX81Oc (7 years ago)

⬐ gravypod

I can't wait for a future where something like that makes it's way into a reMarkable.

A technical video about eink, reprogramming the firmware etc https://www.youtube.com/watch?v=MsbiO8EAsGw

⬐ j_s

It's unfortunate that so much of this specific content is locked up as video. The part is $35 shipped on AliExpress, a great way to begin experimenting.

⬐ mavhc

Unedited video is the fastest kind of content to produce, and the slowest to consume.

Edited video is the slowest kind of content to produce.

⬐ j_s

Unfortunately for me even edited video is still tougher to consume than the written word, when it comes to technical​ content.

I have a much easier time digesting information​ at my own pace.