
Reasonably priced color e-ink display - zdw
https://www.waveshare.com/5.65inch-e-paper-module-f.htm
======
derefr
So, why exactly is it that color e-ink displays try to make every micro-
capsule capable of switching to any of the supported colors; rather than
laying (groups of) CMYK micro-capsules out in a subpixel-like arrangement, and
then wiring them to the substrate such that each of the CMYK "bitplanes" forms
an independently-addressed display signal?

Sure, it'd look like badly-registered offset printing, but that only matters
for small up-close displays, not large far-away displays. (And you could fix
the registration with a precisely-cast diffuser layer, convolving each
subpixel-cluster.)

If this was for reading rather than imagery, and you wanted to have true
blacks, you could also just step _one_ level forward in e-ink technology, and
have the colored micro-capsule groups be _just_ dual-tone (the capsule's color
plus black), giving you {C+K, Y+K, M+K, K} bitplanes.

Are e-ink display manufacturers just imprecise in the way they deposit the
capsules into the panel, making it impossible to address individual capsules?
(If so, that seems like something that could be solved pretty easily with
modern photolithography processes, e.g. etching onto the backing electrode a
grid of "buckets" for individual micro-capsules to fall into.)

~~~
sparker72678
Yes, modern e-ink capsules are not precise. In fact, they're not intended to
be.

If you look at an e-ink display under a microscope you'll see that the
"pixels" are more like "shards" of variously-shaped cells.

[https://twitter.com/sqfmi/status/1178018736684580865](https://twitter.com/sqfmi/status/1178018736684580865)

The "pixels" are made of the actual addressing grid that creates the currents
that attract the pigment in the capsules.

This is part of what ends up giving the appearance of a higher-resolution
display when rendering text, as you get some softer edges "for free." (And
it's what makes the display look 'blurry' for some viewers.)

So, to your question, there's currently no attempt with the technology to
precisely place the colors on the display. The capsules are just spread all
over, and the grid does the work.

~~~
naravara
This makes me sad. Based on what you're describing it's sounding like my dream
of having eReaders that are anywhere near sharp enough to do visually rich,
full color, documents justice (e.g. nature photography, comic books and
graphic novels, well illuminated manuscripts) will never come to fruition.
Barring some kind of transformative breakthrough, of course.

~~~
ajuc
[https://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Co...](https://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/ConeMosaics.jpg/300px-
ConeMosaics.jpg)

Rods in eyes aren't on a regular grid anyway, why should it matter how the
pixels are distributed as long as they cover the plane and are mostly uniform?

~~~
mumblemumble
Because of what was mentioned way up in the original question: The capsules
not being precisely arranged means that they can't be individually
addressable. Meaning that you can't use the trick that non-epaper screens
typically use where each "pixel" is actually a tightly packed cluster of
individual red, green and blue sources that are individually controlled.

So instead, each cell is capable of displaying any color, and they've got a
more complicated refresh mechanism that they use to "write" to them.

And the upshot of _that_ is listed in the specifications from the linked page:
The refresh time on this display is 15 seconds. Which is far, far away from
where it would need to be in order to be a practical option for color
e-readers.

~~~
bduerst
Except you can do multiple colors, by introducing differently charged pigments
inside the capsules:

\-
[https://www.eink.com/assets/img/technology/GIF_Cup_E.gif](https://www.eink.com/assets/img/technology/GIF_Cup_E.gif)

\-
[https://www.eink.com/assets/img/technology/GIF_ACeP_E.gif](https://www.eink.com/assets/img/technology/GIF_ACeP_E.gif)

Refresh rate was always an issue, but it is gradually improving. For static
reading it's not a problem.

------
non-entity
Perhaps someone more familiar with the technology can help me understand. Why
are e-ink displays either tiny (tablet-sized or smaller) or huge (for digital
signage)? I always thought it would be cool to have an x-teen or 20 something
inch e-ink monitor to make reading docs, specs, etc. much easier. I realize
the refresh rate on these things is pretty low, but I've read accounts of some
screens being clocked to around 20hz which may not be enough to watch videos
or play games, but it would be ok for reading and scrolling.

OTOH I did see a 30 something inch e-ink development board for sale once and
wondered if I could hack one together. It was expensive, but that didn't
particularly matter because the company made it clear they wouldn't sell to
consumers or hobbyists.

~~~
sparker72678
There're a few things going on that contribute to this.

1) The rumors are that some of the display manufacturers have contracts with
big device makers to not sell panels direct to consumer. I don't have evidence
to verify this, though.

2) There aren't a lot of displays that exist _at all_ outside of the
small/eReader/Big Sign categories. So there probably just aren't the
production lines out there to push those out.

3) Since refresh rates in even the best cases aren't great, it's unlikely to
get a lot of traction in most markets, so I don't think anyone is pursuing it
heavily.

4) eInk (the company) seems very uninterested in the hobby market at all. They
seem to want a few big contracts, and that's all they're interested in.

~~~
j88439h84
What do you mean by 2? Monitors and TV screens fit that range, no?

~~~
freeone3000
Why would you want a monitor or a tv screen with a refresh rate of 7 fps? And
that's monochrome. For actual RGB output, you need three refreshes, and the
RGB ones are slower, so you might get a frame per second.

~~~
reificator
I'd be ecstatic with a monochrome 20"\+ eink monitor for use after 8:00PM or
so. With the F.lux settings I use on my normal monitor it's practically
monochrome anyway.

7FPS is probably not quite high enough, but I've seen 10-13" displays with
15-20FPS, and that would be fine for normal computing.

I'd probably swap my scrollwheel for PageUp/PageDown to make full page
refreshes a little more pleasant though.

~~~
andai
There was a brief interest in transflective LCD technology in the 2000s and
early 2010s but it seems to have died off (at least for consumer products),
which means sunlight-readable (or candle-readable, for the evenings) LCD with
high refresh rates.

There was even one company (edit: Pixel Qi) putting solar cells in the
displays themselves, so the device recharged while being used in sunlight.

YouTube video comparing Pixel Qi in sunlight with normal backlit LCD
[https://www.youtube.com/watch?v=l1mD6vhp3U8#t=1m45s](https://www.youtube.com/watch?v=l1mD6vhp3U8#t=1m45s)
(around 01:45)

------
chrismorgan
There are serious trade-offs in these things:

• In monochrome panels, you can get 16 shades, and a full refresh in under a
second (with partial refresh much faster, as tight as very few milliseconds
for small areas, or commonly 30fps full-screen update if you’re willing to
compromise a bit on image quality).

• In colour panels, you don’t seem to get shades or rapid refresh: seven
colours means you get a seven colour palette, so you’ll have to use dithering
to get any in-between colours; and you don’t get partial updates at all: even
the fastest coloured panels take a couple of seconds to update the image, and
the more colours you add the slower it is.

If I’m wrong about these and there _are_ colour panels with more interesting
colour or partial refresh, I’m interested to hear. I just haven’t seen any,
and have done _some_ looking.

The long and the short of it is that colour e-ink displays are only useful for
display use, not for individual devices like ebook readers or computer
displays.

~~~
zestyping
Why does the refresh time depend on the size of the region updated? Forgive my
ignorance—I'm imagining that the limiting factor would be the time it takes
for the grains to physically flip over, because they all flip concurrently.

~~~
pocak
Only one row at a time has voltage applied to it. In one update, the image is
scanned out multiple times, so it appears as if all pixels were changing
simultaneously (and perhaps they do, if the electrodes have significant
capacitance.)

With fewer rows to update, each row gets a push more often, flipping the
grains faster.

------
swagonomixxx
I am desperately waiting for semi-high refresh rate (20Hz-30Hz) e-ink displays
so that I can replace my traditional HD display with them.

They're significantly easier on the eyes and they're a joy to use. I don't
particularly care about color. One thing I'm wondering though, is what are the
technical challenges behind building such a display?

Ideally, I'd like to be able to use an Android device that renders onto e-ink.
I don't particularly care for watching videos and such - most of my time on my
phone is spent sending and reading IM's (Signal, text, e-mail) rather than
viewing media, so lower refresh rates is not something I really care about.

Where are the shortcomings causing e-ink displays to have very low refresh
rate? Does it have to do with modern rendering technology being so well
optimized for color displays that they simply are not performant for e-ink?

~~~
sparker72678
Here's how these work:

1) Take a fluid, color it mostly white(ish).

2) Suspend a bunch of tiny black "balls" inside this fluid. The balls need to
be charged so they can be attracted to an electric field.

3) Squish this fluid between some glass.

4) Put a grid of electrodes on the back that you can address.

5) Now, using some clever AC patterns, you can address any "pixel" on your
grid, and apply a charge there, that will attract or repel the little balls.

6) When you attract the balls, that spot turns black, because you just see the
balls above the fluid.

7) When you repel the balls, that spot turns "white" because you just see the
fluid, not the balls.

The trick is that moving the balls back and forth (6/7) is a physical process,
and requires time. They _have_ to move a physical distance, and if that fluid
lets them move too easily then they won't keep their color. The balls will
move and they'll just drift back to some middle ground.

Also, if you're not careful with your approach, you can mess with the charge
of the balls, and they'll no longer respond to the field the way you want.
This is burn-in. (And it's why displays do full-black-to-full-white refreshes
from time to time)

So until we can figure out how to move those balls faster in the fluid, we
really aren't going to dramatically improve refresh rates with this
technology.

Note: "Balls" is a simplification.

~~~
andeee23
I wonder if it will be possible in the future to apply a similar concept for
for a 3d e ink desplay where the grid pulls cells through a 3d medium.

~~~
nimazeighami
3D doesn't really work that way.

If you want a volumetric display, maybe it will work, but the display itself
will need to be the same size as the total volume of depth you want to create,
e.g. digital objects can not appear outside the screen.

Due to the fact that eInk is a non-backlit technology, I can't imagine
creating a glasses-free stereoscopic effect using eInk.

------
caleb-allen
If you are having issues with the site loading you can try this archive link
[https://web.archive.org/web/20200717131125/https://www.waves...](https://web.archive.org/web/20200717131125/https://www.waveshare.com/5.65inch-
e-paper-module-f.htm)

~~~
vikramkr
Thanks for the link. Looks like they've been hugged to death at the moment.

------
nicoburns
I'm still sad that the Mirasol displays
([https://en.wikipedia.org/wiki/Interferometric_modulator_disp...](https://en.wikipedia.org/wiki/Interferometric_modulator_display))
never made it into mainstream products. They seemed to be the best of both
worlds: high refresh rates, colour, and no power consumption when not
refreshing.

~~~
AshamedCaptain
I had one of the qualcomm toqs (which used a small mirasol display).

It didn't look that much better (or distinguishable, for the matter) than one
of those reflective LCDs (e.g. Pebble's). And reflective "memory" LCDs also
have almost negligible -- though not zero -- power consumption. Except for
maybe signage products most people don't care about this difference, and LCD
is way cheaper and mainstream, so...

It's no surprise that many manufacturers just put an LCD and try to get away
by calling it "ePaper". There is a lot of geek appeal here, but I'm not really
sure if we really need any new technology for "mainstream".

~~~
matmann2001
Also had a Toq. Probably one of my favorite smartwatches, and would have loved
to see it live long enough to run Android Wear. Unfortunately, Qualcomm isn't
a product company and the Toq was essentially a proof of concept for both
Mirasol and their new (at the time) line of smartwatch-focused Snapdragon
chips. They managed to convince most of the major real smartwatch OEMs to use
Snapdragon but the Mirasol just never got off the ground. Apparently
manufacturing was very difficult, as you might imagine, and they were hitting
limitations on pushing the color depth.

------
GekkePrutser
Waveshare is really great for making eInk accessible to makers. I've got
several of their products and I love them. Design and documentation are
excellent. For most products they even provide libraries and/or sample code. I
usually order from them directly, though it comes from China it's fairly fast
compared to aliexpress and the like (think more like 2 weeks than 2 months)

By the way, one thing I don't get is why the pictures have such low saturation
but the "demo" view shows really excellent saturation. Are there constraints
when mixing colours perhaps?

Edit: This was explained below by sparker72678:
[https://news.ycombinator.com/item?id=23900165](https://news.ycombinator.com/item?id=23900165)
. I didn't know they worked this way.

------
orlandohill
I've been using a 13.3" Dasung Paperlike HD-FT monitor for a few months. I use
it without the front light, and set the display to 2x magnification. I'd
highly recommend it to anyone having problems with LCD screens.
[http://dasungtech.com/](http://dasungtech.com/)

~~~
zcrar70
How have you been finding it? Do you use it as your main monitor? (Or only at
specific times / alongside a traditional monitor?)

~~~
orlandohill
It works perfectly for reading documentation, writing code, and browsing the
web. The refresh rate is fast enough to watch movies, but I haven't done that
yet. Switching windows leaves faint artifacts on the screen, but I barely
notice them, and there's a refresh button if I want to look at a detailed
still image. I use it as my only monitor, and keep my laptop screen turned
off. About once per week I'll toggle to my laptop's color monitor to view the
art of a Kickstarter campaign, etc.

I don't miss color syntax highlighting, and it's much more relaxing on the
eyes. I could imagine others using it as their main monitor in a joint display
setup, code in e-ink, browser in color.

------
ravenstine
Wait a sec, they have multi-color e-ink now and not just red or green? I
cannot wait until we can get large versions of these that can hang on my
walls! I'd love to put them in frames and have different paintings rotate in
and out.

~~~
tracker1
I've been considering building a 2-way mirror display with a regular lcd
myself. Would prefer a larger e-ink, but they just seem too expensive for what
they are.

------
folken
The display has an SPI interface with a 15s per page refresh rate and is only
useable for sinage.

There is however the Hisense A5C phone with Color E-ink Display now on the
market and it features a decent refresh rate.

[https://forum.xcsoar.org/download/file.php?id=1113](https://forum.xcsoar.org/download/file.php?id=1113)

~~~
Valord
If interested check out
[https://goodereader.com/blog/](https://goodereader.com/blog/) for more info
on what's coming out for e-ink.

Not affiliated, just a fan.

------
Abishek_Muthian
Waveshare e-ink displays are good for small DIY projects, but not more than
that due to questionable reliability over long term use, but I'm glad they
exist and they have good documentation.

Also, since the refresh rates are limited it's not like we can build ourselves
a nice external large e-ink display for our reading pleasure and for the sake
of our eyes.

There's a need gap for 'Affordable E-Ink large external displays'[1], last
time we discussed about it here it was pointed out that the likely reason for
we not having such displays are due to IP.

[1][https://needgap.com/problems/43-affordable-e-ink-large-
exter...](https://needgap.com/problems/43-affordable-e-ink-large-external-
displays-eink-displays) [Disclosure: It is my problem validation platform].

------
ilaksh
I hope that one day truly large scale e-ink systems become somewhat
affordable. I think it could be revolutionary for architecture.

The appearance of buildings would no longer necessarily be static.

More generally, I believe that the extreme minimalism, "tranquility" (or
blandness) and simplicity of more contemporary styles may some day become
unpopular.

So I expect that we will see trends in the opposite direction eventually. More
colors. Maybe a changing facade with e-ink. Rather than simple, boxy shapes,
more intricate and more organic shapes. Large-scale 3d printing could make the
use of such forms more practical.

I also expect to see architecture that is more dynamic in that it will
automatically reconfigure itself in response to weather changes or the
day/night cycle, winter/summer, etc.

------
abetusk
Not directly related but there's an awesome "Open Book" project which is an
open source hardware e-book reader [1].

[1] [https://github.com/joeycastillo/The-Open-
Book](https://github.com/joeycastillo/The-Open-Book)

------
pmdulaney
How difficult would it be for a maker type to cobble together a portable vim
editor using one of these?

~~~
donaltroddyn
The 7-colour version doesn't support partial refresh and has a 15s refresh
time (~0.067Hz refresh rate), so you'd want to be a _really_ confident touch
typist.

~~~
ranger207
Sounds like it's time to learn ed.

~~~
jrockway
ed echoes back the characters you input as you type them. This display would
not be able to do that.

~~~
tzs
Put a one or two line black and white LCD on the bottom to show your ed-like
commands, with the e-ink just showing the results of edits.

------
fulafel
Anyone know how tolerant these are of UV, how long will it survive in frequent
direct sunlight?

~~~
sparker72678
I don't know about UV itself, but the spec sheet on my 7" Waveshare eInk
display says to avoid direct sunlight and extreme heat.

------
dmitrygr
Attempted to look at the datasheet. There is no link, there is an image that
says "user manual" and "dev resources" but it is not clickable. There is a
note that says _" Resources for different product may vary, please check the
wiki page to confirm the actually provided resources."_

ok, i clicked the wiki link: www.waveshare.com/wiki/5.65inch_e-
Paper_Module_(F)

 _" There is currently no text in this page. You can search for this page
title in other pages, or search the related logs, but you do not have
permission to create this page."_

so, not really hobbyist friendly

------
pfrench42
Is it just me or should this be four color CMYK like a regular printer?

~~~
sparker72678
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](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](https://en.wikipedia.org/wiki/Electrowetting#Applications)

~~~
sparker72678
Oh, fascinating! This looks really interesting!

------
staycoolboy
I did NOT expect this to be under US$100. Definitely going for low power with
SPI interface, but I don't get their refresh claim. SPI tops out around
1MB/s... 600x448x7 is ~235KB or 4 fps at 1MBps... but 15fps? That'd be 7MB/s,
which is nigh impossible on SPI.

EDIT: 15 SECONDS PER FRAME, not 15fps. Thanks everyone for pointing that out.
Still, amazingly cheap ... and almost no standby current after programming.

~~~
LeifCarrotson
> _FULL REFRESH TIME 15s_

That's 15 seconds per frame, or 0.067 fps.

That refresh rate is fine if you're using it to show the price of a rack of
clothing, or various sensors - but you're not going to get smooth-scrolling
text with it. The low-power interface is for those same battery-backed retail
signage applications, where you're driving this, the microcontroller, and the
wireless receiver with 3.7v from a coin cell.

Glad to see these becoming available for consumers and hackers! They've been
hard to come by for years.

~~~
JKCalhoun
Or a "magic mirror" showing weather, calendar, time: you know, hours and
minutes only :).

~~~
SahAssar
"Magic mirrors" don't work with e-ink since they require a lit display to
shine through the mirror.

~~~
JKCalhoun
Good point. I suppose it just becomes a display then, rather than mirror — but
with similar data.

More like the ubiquitous readouts in the "2001" Discovery ship.

------
bufferoverflow
600x448px resolution makes it very limied for most applications. And it's too
expensive to be used as a tag in a store.

------
ds
Havent looked into this much- What is the maximum 'refresh' rate you can get
out of something like this?

~~~
criddell
The page says 15s.

~~~
OkGoDoIt
That is what the page says, but can that possibly be right? I know e-ink tends
to have very low refresh rates but taking a full 15 seconds to redraw seems
excessive. I have found sites like this often have pretty obvious errors on
them, is it likely this is correct or a typo?

~~~
floatingatoll
15 seconds doesn’t make sense for a handheld reader. Are there other scenarios
where it does make sense?

~~~
itronitron
Event specific signage such as 'Donner Party' in Conference Room C could be
useful for many hotels and convention centers.

------
efreak
> Suitable For Price Tags, Asset/Equipment Tags, Shelf Labels, Conference Name
> Tags...

Maybe it's just me, but this seems quite expensive for a price tag. It also
seems quite large for a name tag. I get that eink is useful in general for
these cases, but this doesn't seem to be the best example.

------
dubcanada
What I really would like is a touchscreen version of this. I think the idea of
a "panel" is amazing, but I'd like either a touch overlap or touch screen
built in.

Anyone know of any e-ink with touch built in? can be black and white.

~~~
swagonomixxx
The Amazon Kindle has a touch e-ink screen. You can use it to read books (mobi
format) or browse the web (albeit in a very limited fashion - but I use it to
browse HN and works fine).

~~~
dubcanada
I guess I should have been more specific, I meant one I could modify/make a
custom app for/what ever.

~~~
sparker72678
I've never seen a stand alone item that included a touch layer. I think you're
stuck repurposing another device to pull this off.

------
beshrkayali
Are there any alternative e-ink displays with lower screen refresh time? 15
seconds is a bit much. Or at least one that'd allow partial refresh? Not
necessarily with color.

------
renewiltord
Who knows how to reasonably get power to stuff like these on walls with
unobtrusive cables? Anyone have any arrangements at home that make these look
nice or if not, unnoticeable?

~~~
pi-rat
\- Pull power inside the wall. Drill a hole on top, another one on the bottom,
use one of those magnetic cable pullers. Wires for 5v requires two tiny holes
in drywall that's easy to patch later. There's also pretty kits made for TVs,
but those require bigger holes (for HDMI, power, etc).

\- Pull power from the room behind the wall. Maybe it's more out of view here.

\- Place it next to a door, remove part of the frame, run wires inside the
door frame.

\- Cable channel exists in many different shapes and sizes, not only the
boring box ones.

\- Go the opposite route, why hide your cable? Make it stand out. Like those
wall lamps with a brightly coloured / patterned cable hanging in loops down
the wall. Turn it into wall art.

You can find some pretty wall mounted tablets in the homeautomation and
homeassistant reddits :)

~~~
renewiltord
Thank you!

------
cranium
Don't think about making anything remotely real time as the full display
refresh takes around 15s and there is no partial refresh available.

------
rglover
Does anybody know of a decent micro controller that could be paired with one
of these on the form factor/scale of a Kindle?

------
grzeczko
Are there any e-ink displays that are touchscreen? I did a whole lot of
searching and couldn't find any.

~~~
martin-adams
Like the Kindle? I’d imagine the tech exists somewhere.

~~~
grzeczko
Not the Kindle. Looking for a touchscreen e-ink display I can use with my
Raspberry Pi

------
Animats
It's still 3x as expensive as an LCD display of the same size. The LCD display
has full color, too.[1] The E-Ink display offers only 7 faded colors.

[1] [https://www.buydisplay.com/5-inch-lcd-screen-tft-
module-800x...](https://www.buydisplay.com/5-inch-lcd-screen-tft-
module-800x480-vga-video-av-driver-board)

~~~
kevin_thibedeau
Sunlight readable though.

~~~
Waterfall
Never used a b+w monochrome display before? I remember the non color iPods
were great in the sun.

------
1MachineElf
15s refresh time. Not bad I guess for certain applications.

------
matmann2001
I wonder what the refresh time on this looks like. I recently finished a
project with a red/black/white e-ink display, and the docs for it listed a
worst-case refresh time of up to 14 seconds.

~~~
sparker72678
The docs say 15 seconds per refresh.

------
joshu
i would like a laptop with four of these. I arrange my xterms that way anyway.

------
phaedrus
I just ordered it.

