8 ms·

Eink always could be driven quickly. The issue is that LCDs are more powerful efficient at high refresh rates EInk needs a lot of power to move the heavier ink

Eink always could be driven quickly. The issue is that LCDs are more powerful efficient at high refresh rates EInk needs a lot of power to move the heavier ink particles around. If you are doing that more and more rapidly, then even more power is drawn. By 75Hz, I'm almost certain that LCD is far more power efficient. The LCD pixel (aka the liquid crystal) is a glorified capacitor, it takes some power to charge but it's exceptionally 'light' compared to eink. That's why LCDs can go faster and faster. It's just physics. A capacitor / twisted crystal uses less power to turn on or off than EInk. --------- EInks advantage is that if you turn off power, the ink stays put. So you spend a ton of power moving the ink around and then save lots and lots of power over the next seconds, minutes or more. That's why EInk is ideal for once-a-day updates of prices (or other retailer tasks). The less you update, the less power used.

sirwhinesalot 1y ago
Flipping pages right now is very annoying. Slow and with the weird redrawing flashing. If they can find a way to fix that it'll be 100% worth it, even if it means high power draw on page changes.
- b112 1y ago
  You must have a very old, or very weird device. That sort of behaviour is more than a decade old. There are refresh modes now which are very good at partial updates.
  - sirwhinesalot 1y ago
    It's a pretty recent Kobo device.
    - b112 1y ago
      I have one of these: https://www.amazon.com/dp/B0CDBYFH81 https://www.amazon.com/dp/B0CDBYFH81 and a colour Boox. The refresh on the Boox is so fast, you can watch video. I don't think the Meebook has refresh issues, it's definitely very fast for back/forward. Of course I don't have page turn animations on. I use the kindle app on it, and KOreader. If you get this, know that there is a thread to drop in a script, so the volume buttons page turn correctly when upside down. If you live in Amazon turf, you can always buy and return if not suitable? There are some reviews on Amazon.
    - vaughnegut 1y ago
      Kobo devices do a full page refresh periodically, which is probably what you're seeing. iirc it will do it on chapter transitions to make it less jarring. Basically, it's intentional and relatively rare (unless you have really really short chapters).
- Podrod 1y ago
  [dead]
alok-g 1y ago
Is this saying that it is an either-or situation? Ideal would be a device that can be written fast when needed, but can also hold. Is there some more fundamental thing at a pixel level that links agility with retention?
- bityard 1y ago
  Depending on your requirements, yes: https://sharpdevices.com/memory-lcd/ https://sharpdevices.com/memory-lcd/
- dragontamer 1y ago
  No. I'm saying Tech#1 is more power efficient at 0.05Hz while Tech#2 is more power efficient at 50Hz. Mysterious future Tech#3 will break the rules. OLED for example uses far less power on black pixels. It's just different.
- numpad0 1y ago
  E Ink uses microscopic ink bubbles that gets attracted to positive and negative voltages. The ink stays around when attraction stops, holding image. But the ink also require much stronger force than regular LCDs to move around. LCDs use articulation of liquid crystal chemicals that change shape thus polarization upon application of voltages. They tend to slowly deform back to "the other" state when voltages are removed, and also tend to chemically break down if not moved back to the neutral state. LCDs are driven in pseudo-alternating current for this reason, and never held at either extremes for long time, for this reason. So you can drive E Ink at 75Hz or whatever, it'll just take more power than it takes LCD to do so, and the last pixel states will persist. Or you can leave LCDs at extremes and disconnect the power, but it will lead to degradation if intentionally used that way. What you can't do is 1) "watt per frame" figures of LCD, with 2) persistence, and 3) long life. (1, 3) is LCD, (2, 3) is E Ink, (1, 2) is LCD abused as if it's E Ink at expense of rapid degradation, and (1, 2, 3) is the holy grail.
  - mcdonje 1y ago
    Are LCD screens driven on a pixel by pixel basis, or is the entire screen driven on each refresh? Because the article says they're only causing changed pixels to refresh. If so, you're probably still right when it comes to watching a video or something, but e-ink could be more efficient for drawing, writing, or reading.
hungmung 1y ago
I thought the issue was duty cycle, and that low refresh rates kept the screen working longer. Has e-ink tech gotten around this?
- InsideOutSanta 1y ago
  That's what I'm wondering about. I wouldn't mind temporary higher energy usage to get smoother interactions, but I'm not sure what the long-term impact on the screen is.
  - alex-a-soto 1y ago
    I’d recommend watching the video below, where we talk about how fast refresh affects a panel’s lifespan. https://www.youtube.com/live/okjJURIejIY?feature=shared&t=2491 https://www.youtube.com/live/okjJURIejIY?feature=shared&t=24...
smusamashah 1y ago
Do e-ink screens expire? Like screen slowly loose the ability to move the particles around, or the particles loosing the ability to move with charge. If so, won't high refresh rates degrade eink rapidly.
- bebna 1y ago
  Yes you can kill or degrade them if you drive them too hard, but achieving higher refresh rates and less ghosting is mostly about finer calibration and faster lookups on bigger tables
- alex-a-soto 1y ago
  I’d recommend watching the video below, where we talk about how fast refresh affects a panel’s lifespan. https://www.youtube.com/live/okjJURIejIY?feature=shared&t=2491 https://www.youtube.com/live/okjJURIejIY?feature=shared&t=24...
  - fdsfdsfdsaasd 1y ago
    For dynamic content, a higher refresh rate absolutely will lower an eink panel's lifespan. As the refresh rate increases, more of the underlying content's changes will be captured and more pixels will change state.
- Modified3019 1y ago
  In the DIY electronics scene, I’ve occasionally come across posts about small cheap e-ink displays essentially burning in and how to try and avoid it (shifting things around like on OLED) https://github.com/esphome/feature-requests/issues/1109#issuecomment-2629029382 https://github.com/esphome/feature-requests/issues/1109#issu... This could be actual burn in, or it could be a failure in how they are refreshing (with some potential fix if refreshed properly). I’m not familiar enough to be certain myself, but I personally suspect they are likely being driven too hard and are truly damaged. In normal e-reader use I’ve never seen this as a practical issue.
- cyberax 1y ago
  I have an e-ink display that's now 15 years old. It's definitely a bit less clean, there is sometimes mild ghosting even after doing a full refresh. Doing two refreshes in quick succession fixes that. I also have another display that was exposed to full sunlight through a window for about 8 years. It's now a bit faded as a result. All in all, I consider it pretty good.
Wowfunhappy 1y ago
I mean, it depends on just how much power is needed I guess, but I'd be willing to make the trade for e-ink's contrast.
alex-a-soto 1y ago
Our driver board, under continuous use, draws about 1 to 1.5W. A recent article below goes into some detail about our design choices. https://www.crowdsupply.com/modos-tech/modos-paper-monitor/updates/a-technical-deep-dive-into-glider https://www.crowdsupply.com/modos-tech/modos-paper-monitor/u...
- dragontamer 1y ago
  Thanks. That article seems to have the quote I was looking for. > E-ink screens are quite power hungry when it comes to peak current. Modern high-resolution panels can consume >20 W peak. This is where I was wondering and yeah, 20+W is pretty hefty to support a relatively small 8" EInk screen or something. All those updates cost all that power as long as updates are occurring. Maybe you can optimize many of them away (if some parts of the screen don't move, especially if software was rewritten to optimize for the display). More importantly, it sounds like you've created a full custom FPGA controller over the voltages that go into an EInk display? That's impressive in its own right even if I don't think 75Hz is a good idea lol. -------- FPGA or Full Blown Microprocessor are the only choices here. A high power SIMD/NEON arm64 probably could do the job, but I think the Spartan6 is a good choice as well and has more obvious and straightforward parallelism (and probably all the pins required to control the screen. Even a big microprocessor won't have as many low latency pins as an FPGA).
  - alex-a-soto 1y ago
    > Maybe you can optimize many of them away (if some parts of the screen don't move, especially if software was rewritten to optimize for the display). Yes, that’s definitely something we want to work toward. As the community grows, we hope to tackle these kinds of optimizations together. > A high power SIMD/NEON arm64 probably could do the job, but I think the Spartan6 is a good choice as well and has more obvious and straightforward parallelism Yes, precisely for the reasons you stated. We also talk more about it below: - https://www.youtube.com/live/okjJURIejIY https://www.youtube.com/live/okjJURIejIY - https://github.com/Modos-Labs/Glider?tab=readme-ov-file#design-of-caster-and-glider https://github.com/Modos-Labs/Glider?tab=readme-ov-file#desi...
ThrowawayR2 1y ago
E-Ink's other advantage is being a non-emissive display. Transflective LCD displays have low contrast. I'm literally holding an e-ink tablet over the transflective monitor I'm typing this on and the difference in contrast at the same ambient illumination is considerable. If the price were right, I'd definitely consider a 75 Hz e-ink monitor even if the power draw was more than a normal LCD monitor.
- akvadrako 1y ago
  Transflective LCD is bad but e-ink has terrible contrast compared to normal LCD displays. Like 4:1 vs 1000:1.
  - psd1 1y ago
    Maybe, but LCD panels are a light source, so it's not apples-to-apples. I _perceive_ eink as higher contrast than any LCD.
    - pasc1878 1y ago
      That is odd as I definitely do not perceive that. My Kindle has much less contrast than my iPad, phone or computer - albeit I have brightness turned up. I only use the Kindle as its battery will last over a day if reading my iPhone will not and also if reading in bright sunlight.
  - account42 1y ago
    That depends on the external illumination. LCD contrast goes to shit under bright light.
    - akvadrako 1y ago
      It's bad but 1000+ nit displays under indirect light on sunny days seems competive with ratios around 4:1.
Yoric 1y ago
Out of curiosity, if you have 75Hz but you're refreshing sparingly (e.g. you're in VSCode writing, unless you're scrolling, most pixels remain unchanged), wouldn't e-ink remain power-efficient?
- teucris 1y ago
  That requires the operating system to “hint” to the display that there’s no refresh necessary and for the display to shut down during those times. That’s currently not supported as these kits just take a video signal, but it’s something being worked on for a future version!
  - ahartmetz 1y ago
    Edit: You work on that stuff, right? Then this armchair experting feels silly, just imagine it's for other readers. It seems much more practical (if a little less power-efficient) to implement the no diff -> no refresh logic for screen regions in the display hardware. The RAM and logic for a display-side framebuffer can't be expensive today, a couple of Euros for the extra board space and chip(s). If that stuff takes off, just additional transistors in the all-in-one ASIC. For the whole screen, that more or less already exists in laptop hardware: "panel self-refresh". HDMI and DiplayPort might need a new extension or something? Is there anything?
    - wtallis 1y ago
      The Embedded DisplayPort standard has had the panel self-refresh feature since 2011, and the partial update feature since ~2015. I found a press release from Parade in early 2017 for a TCON supporting the partial refresh feature. I don't think there's anything missing from the ecosystem other than a strong impetus to use those features.
    - teucris 1y ago
      Yes! I work with the Modos team. You’re exactly right - ideally we want region-based refresh hinting. The SDK supports some region based features - we’d like to extend that functionality.
detourdog 1y ago
I have been thinking e-ink would be good for weather reports on boats.
amelius 1y ago
> The LCD pixel (aka the liquid crystal) is a glorified capacitor Would it be possible to re-use the power that is stored in them?
- wkat4242 1y ago
  Nah the energy is negligible.
- dragontamer 1y ago
  I assume that's what Sharp Memory LCDs are doing to reach their absurdly low power specs. I dunno if LCD screens are multiplexed, but embedded LCDs could need as many as 8x on/off cycles per pixel (because you save 87% fewer wires if you chain 8x pixels on the same line and then put them on different biases and have weird COMmon pins and rows and crap). Sharp claims that a bit of storage is on each LCD/capacitor and this saves power somehow with smarter decision making. I assume it's minimizing the wasted power somehow (or even recycling the previous power shoved into the capacitor, which typically just goes to waste). It's some proprietary formula in any case, so it's all guesswork. Only the Sharp Engineer/Inventor would know for sure.
  - saltcured 1y ago
    From what I've tried to glean from patents and whitepapers, they have memory in the panel so that each sub-pixel can hold its state without being driven by the controller. The controller also can address sub-regions under the control of the application processor. The net effect is that the app can vary refresh rate and also update a small part of the screen while leaving the rest static. In Garmin smartwatches, this is used to switch between 1 Hz, 1/60 Hz, and a hybrid mode where the overall screen is 1/60 Hz and small part is updated at 1 Hz. E.g. the seconds digits may remain active while the rest of the screen is static. It also seems like they use more interesting sub-pixel arrangements. The limited color depth may involve different combinations of 1-bit sub-pixels rather than any cells driven into partially twisted states. I've seen diagrams claiming some white (unfiltered) and RGB filtered sub-pixels of different sizes.
wolrah 1y ago
> EInks advantage is that if you turn off power, the ink stays put. E-ink's other advantage is that it reads like paper. In a desktop context I could not possibly care less about the power consumption, but being able to read a forum thread, chat channel, HN discussion, etc. without a backlight would make my eyes very happy.
- luqtas 1y ago
  there's no evidence/meta-analysis pointing e-ink screen tiring eyes more/less than LCD
  - wolrah 1y ago
    Is there any actual scientific study saying anything either way? I'm aware of a lot of anecdotal evidence in favor of e-ink displays being easier on the eyes than normal LCDs in some way, my own personal experience included, but I will happily admit I'm wrong if there are studies indicating otherwise. I like my Kindle and DIY e-ink weather display but I'm not religious about it. I wouldn't be shocked to find out it was just a weird placebo thing because it's different.
    - luqtas 1y ago
      i don't think there are much but i made my research a decade ago after realizing i was having a good time with my smartphone compared to my e-reader [1] suggests that LCD even increases processing speed compared to e-ink [0] https://pubmed.ncbi.nlm.nih.gov/22762257/ https://pubmed.ncbi.nlm.nih.gov/22762257/ [1] https://bop.unibe.ch/JEMR/article/view/2338/3534 https://bop.unibe.ch/JEMR/article/view/2338/3534 there's a study from Havard concluding "e-ink is 3 times better for eye health than LCD" but it feels rather dubious from the claims (blue light stressing more the retina... like i couldn't use a glass or apply a filter on my screen), light intensity (again...), in-vitro study and who funded the study (a great e-ink screen producer) -> https://sid.onlinelibrary.wiley.com/doi/10.1002/jsid.1191 https://sid.onlinelibrary.wiley.com/doi/10.1002/jsid.1191 i probably read hundred books since i sold my e-reader and moved to my smartphone. i really like having a single device. battery is fine. physical books with images still rocks but maybe becuse i don't have a tablet :)
m463 1y ago
Actually, the advantage is that it is reflective and works better in high ambient light.
maksimur 1y ago
I wonder if we could engineer a lighter ink
micheljansen 1y ago
For mobile devices that matters, but plenty of use cases for stationary displays, including desktops.
rldjbpin 1y ago
IANAE but won't e-ink at high refresh rates have the same benefit as OLED in terms of only refreshing what needs changing? perhaps in practical situations the power consumption should be lower than the worst-case scenario.
Aerroon 1y ago
So I guess an e-ink display would not be good with my book reading habits then. I will often scroll a few lines at a time and that sounds power expensive.
- bee_rider 1y ago
  It would still only need to refresh fast enough to keep up with your line reading rate, right? Couldn’t be much more than 1 fps.
  - Aerroon 1y ago
    Oh, that's not what I was thinking about. I was thinking about its power efficiency coming from not being to update the screen. Scrolling would force a lot more updates on it.
- carlosjobim 1y ago
  You just have to read your books like you would read a book.
gdbsjjdn 1y ago
In my experience using e-ink readers (admittedly I have a Kobo, which may not be the state of the art), I would like to refresh the screen rapidly in bursts -navigating menus, flipping past an index - and then have a non-backlit screen with low power cost to show the same content for a while. In other words, a variable refresh rate. If you think of the refresh rate not as a constant frequency but as variable with user input, there are some cases where driving eink quickly in short bursts could make sense? It seems like this project offers a foundation for such a controller, where e-reader controllers are strictly optimizing for low refresh rates. E-ink is not going to be competitive for playing a video game or watching a video, but you can create a more responsive experience with less eye strain for typical tasks like marking up documents.
- lucasacosta_ 1y ago
  That sounds like the way to go. In terms of reading books (my normal usage of e-ink readers) you don't need 60hz when flipping a page, but it's a must when trying to use an app menu, or using Google Drive for example. Identifying when to increase the refresh rate may be a challenge but I can see it pretty doable for this kind of "limited" scenarios where you either read or navigate a storage app.
- alex-a-soto 1y ago
  Yes, that’s the mental model I’ve been working from. Variable refresh tied to user input makes a lot of sense: short bursts of speed for navigation or editing, then settling into a low-power static state. Part of the challenge is deciding what belongs in hardware and what should sit higher up in the OS or software stack. Hopefully, as more people get the kits and the community grows, we’ll be able to think through these questions together and explore where the right balance between hardware and software should be.
constantcrying 1y ago
It is not as easy as that. The nature of EInk displays allows them to be usable without a backlight LCDs need backlights constantly, any analysis which doesn't take this into account is irrelevant. In any case, it is not clear that, even if EInk Displays are somewhat worse in power consumption, they aren't a superior display technology.
JoelMcCracken 1y ago
So why do eink monitors with ac power supplies still have lower refresh rates?

sirwhinesalot 1y ago

Flipping pages right now is very annoying. Slow and with the weird redrawing flashing. If they can find a way to fix that it'll be 100% worth it, even if it means high power draw on page changes.

b112 1y ago
You must have a very old, or very weird device. That sort of behaviour is more than a decade old. There are refresh modes now which are very good at partial updates.
- sirwhinesalot 1y ago
  It's a pretty recent Kobo device.
  - b112 1y ago
    I have one of these: https://www.amazon.com/dp/B0CDBYFH81 https://www.amazon.com/dp/B0CDBYFH81 and a colour Boox. The refresh on the Boox is so fast, you can watch video. I don't think the Meebook has refresh issues, it's definitely very fast for back/forward. Of course I don't have page turn animations on. I use the kindle app on it, and KOreader. If you get this, know that there is a thread to drop in a script, so the volume buttons page turn correctly when upside down. If you live in Amazon turf, you can always buy and return if not suitable? There are some reviews on Amazon.
  - vaughnegut 1y ago
    Kobo devices do a full page refresh periodically, which is probably what you're seeing. iirc it will do it on chapter transitions to make it less jarring. Basically, it's intentional and relatively rare (unless you have really really short chapters).
Podrod 1y ago
[dead]

alok-g 1y ago

Is this saying that it is an either-or situation? Ideal would be a device that can be written fast when needed, but can also hold. Is there some more fundamental thing at a pixel level that links agility with retention?

bityard 1y ago
Depending on your requirements, yes: https://sharpdevices.com/memory-lcd/ https://sharpdevices.com/memory-lcd/
dragontamer 1y ago
No. I'm saying Tech#1 is more power efficient at 0.05Hz while Tech#2 is more power efficient at 50Hz. Mysterious future Tech#3 will break the rules. OLED for example uses far less power on black pixels. It's just different.
numpad0 1y ago
E Ink uses microscopic ink bubbles that gets attracted to positive and negative voltages. The ink stays around when attraction stops, holding image. But the ink also require much stronger force than regular LCDs to move around. LCDs use articulation of liquid crystal chemicals that change shape thus polarization upon application of voltages. They tend to slowly deform back to "the other" state when voltages are removed, and also tend to chemically break down if not moved back to the neutral state. LCDs are driven in pseudo-alternating current for this reason, and never held at either extremes for long time, for this reason. So you can drive E Ink at 75Hz or whatever, it'll just take more power than it takes LCD to do so, and the last pixel states will persist. Or you can leave LCDs at extremes and disconnect the power, but it will lead to degradation if intentionally used that way. What you can't do is 1) "watt per frame" figures of LCD, with 2) persistence, and 3) long life. (1, 3) is LCD, (2, 3) is E Ink, (1, 2) is LCD abused as if it's E Ink at expense of rapid degradation, and (1, 2, 3) is the holy grail.
- mcdonje 1y ago
  Are LCD screens driven on a pixel by pixel basis, or is the entire screen driven on each refresh? Because the article says they're only causing changed pixels to refresh. If so, you're probably still right when it comes to watching a video or something, but e-ink could be more efficient for drawing, writing, or reading.

hungmung 1y ago

I thought the issue was duty cycle, and that low refresh rates kept the screen working longer. Has e-ink tech gotten around this?

InsideOutSanta 1y ago
That's what I'm wondering about. I wouldn't mind temporary higher energy usage to get smoother interactions, but I'm not sure what the long-term impact on the screen is.
- alex-a-soto 1y ago
  I’d recommend watching the video below, where we talk about how fast refresh affects a panel’s lifespan. https://www.youtube.com/live/okjJURIejIY?feature=shared&t=2491 https://www.youtube.com/live/okjJURIejIY?feature=shared&t=24...

smusamashah 1y ago

Do e-ink screens expire? Like screen slowly loose the ability to move the particles around, or the particles loosing the ability to move with charge. If so, won't high refresh rates degrade eink rapidly.

bebna 1y ago
Yes you can kill or degrade them if you drive them too hard, but achieving higher refresh rates and less ghosting is mostly about finer calibration and faster lookups on bigger tables
alex-a-soto 1y ago
I’d recommend watching the video below, where we talk about how fast refresh affects a panel’s lifespan. https://www.youtube.com/live/okjJURIejIY?feature=shared&t=2491 https://www.youtube.com/live/okjJURIejIY?feature=shared&t=24...
- fdsfdsfdsaasd 1y ago
  For dynamic content, a higher refresh rate absolutely will lower an eink panel's lifespan. As the refresh rate increases, more of the underlying content's changes will be captured and more pixels will change state.
Modified3019 1y ago
In the DIY electronics scene, I’ve occasionally come across posts about small cheap e-ink displays essentially burning in and how to try and avoid it (shifting things around like on OLED) https://github.com/esphome/feature-requests/issues/1109#issuecomment-2629029382 https://github.com/esphome/feature-requests/issues/1109#issu... This could be actual burn in, or it could be a failure in how they are refreshing (with some potential fix if refreshed properly). I’m not familiar enough to be certain myself, but I personally suspect they are likely being driven too hard and are truly damaged. In normal e-reader use I’ve never seen this as a practical issue.
cyberax 1y ago
I have an e-ink display that's now 15 years old. It's definitely a bit less clean, there is sometimes mild ghosting even after doing a full refresh. Doing two refreshes in quick succession fixes that. I also have another display that was exposed to full sunlight through a window for about 8 years. It's now a bit faded as a result. All in all, I consider it pretty good.

Wowfunhappy 1y ago

I mean, it depends on just how much power is needed I guess, but I'd be willing to make the trade for e-ink's contrast.

alex-a-soto 1y ago

Our driver board, under continuous use, draws about 1 to 1.5W. A recent article below goes into some detail about our design choices. https://www.crowdsupply.com/modos-tech/modos-paper-monitor/updates/a-technical-deep-dive-into-glider https://www.crowdsupply.com/modos-tech/modos-paper-monitor/u...

dragontamer 1y ago
Thanks. That article seems to have the quote I was looking for. > E-ink screens are quite power hungry when it comes to peak current. Modern high-resolution panels can consume >20 W peak. This is where I was wondering and yeah, 20+W is pretty hefty to support a relatively small 8" EInk screen or something. All those updates cost all that power as long as updates are occurring. Maybe you can optimize many of them away (if some parts of the screen don't move, especially if software was rewritten to optimize for the display). More importantly, it sounds like you've created a full custom FPGA controller over the voltages that go into an EInk display? That's impressive in its own right even if I don't think 75Hz is a good idea lol. -------- FPGA or Full Blown Microprocessor are the only choices here. A high power SIMD/NEON arm64 probably could do the job, but I think the Spartan6 is a good choice as well and has more obvious and straightforward parallelism (and probably all the pins required to control the screen. Even a big microprocessor won't have as many low latency pins as an FPGA).
- alex-a-soto 1y ago
  > Maybe you can optimize many of them away (if some parts of the screen don't move, especially if software was rewritten to optimize for the display). Yes, that’s definitely something we want to work toward. As the community grows, we hope to tackle these kinds of optimizations together. > A high power SIMD/NEON arm64 probably could do the job, but I think the Spartan6 is a good choice as well and has more obvious and straightforward parallelism Yes, precisely for the reasons you stated. We also talk more about it below: - https://www.youtube.com/live/okjJURIejIY https://www.youtube.com/live/okjJURIejIY - https://github.com/Modos-Labs/Glider?tab=readme-ov-file#design-of-caster-and-glider https://github.com/Modos-Labs/Glider?tab=readme-ov-file#desi...

ThrowawayR2 1y ago

E-Ink's other advantage is being a non-emissive display. Transflective LCD displays have low contrast. I'm literally holding an e-ink tablet over the transflective monitor I'm typing this on and the difference in contrast at the same ambient illumination is considerable. If the price were right, I'd definitely consider a 75 Hz e-ink monitor even if the power draw was more than a normal LCD monitor.

akvadrako 1y ago
Transflective LCD is bad but e-ink has terrible contrast compared to normal LCD displays. Like 4:1 vs 1000:1.
- psd1 1y ago
  Maybe, but LCD panels are a light source, so it's not apples-to-apples. I _perceive_ eink as higher contrast than any LCD.
  - pasc1878 1y ago
    That is odd as I definitely do not perceive that. My Kindle has much less contrast than my iPad, phone or computer - albeit I have brightness turned up. I only use the Kindle as its battery will last over a day if reading my iPhone will not and also if reading in bright sunlight.
- account42 1y ago
  That depends on the external illumination. LCD contrast goes to shit under bright light.
  - akvadrako 1y ago
    It's bad but 1000+ nit displays under indirect light on sunny days seems competive with ratios around 4:1.

Yoric 1y ago

Out of curiosity, if you have 75Hz but you're refreshing sparingly (e.g. you're in VSCode writing, unless you're scrolling, most pixels remain unchanged), wouldn't e-ink remain power-efficient?

teucris 1y ago
That requires the operating system to “hint” to the display that there’s no refresh necessary and for the display to shut down during those times. That’s currently not supported as these kits just take a video signal, but it’s something being worked on for a future version!
- ahartmetz 1y ago
  Edit: You work on that stuff, right? Then this armchair experting feels silly, just imagine it's for other readers. It seems much more practical (if a little less power-efficient) to implement the no diff -> no refresh logic for screen regions in the display hardware. The RAM and logic for a display-side framebuffer can't be expensive today, a couple of Euros for the extra board space and chip(s). If that stuff takes off, just additional transistors in the all-in-one ASIC. For the whole screen, that more or less already exists in laptop hardware: "panel self-refresh". HDMI and DiplayPort might need a new extension or something? Is there anything?
  - wtallis 1y ago
    The Embedded DisplayPort standard has had the panel self-refresh feature since 2011, and the partial update feature since ~2015. I found a press release from Parade in early 2017 for a TCON supporting the partial refresh feature. I don't think there's anything missing from the ecosystem other than a strong impetus to use those features.
  - teucris 1y ago
    Yes! I work with the Modos team. You’re exactly right - ideally we want region-based refresh hinting. The SDK supports some region based features - we’d like to extend that functionality.

detourdog 1y ago

I have been thinking e-ink would be good for weather reports on boats.

amelius 1y ago

> The LCD pixel (aka the liquid crystal) is a glorified capacitor Would it be possible to re-use the power that is stored in them?

wkat4242 1y ago
Nah the energy is negligible.
dragontamer 1y ago
I assume that's what Sharp Memory LCDs are doing to reach their absurdly low power specs. I dunno if LCD screens are multiplexed, but embedded LCDs could need as many as 8x on/off cycles per pixel (because you save 87% fewer wires if you chain 8x pixels on the same line and then put them on different biases and have weird COMmon pins and rows and crap). Sharp claims that a bit of storage is on each LCD/capacitor and this saves power somehow with smarter decision making. I assume it's minimizing the wasted power somehow (or even recycling the previous power shoved into the capacitor, which typically just goes to waste). It's some proprietary formula in any case, so it's all guesswork. Only the Sharp Engineer/Inventor would know for sure.
- saltcured 1y ago
  From what I've tried to glean from patents and whitepapers, they have memory in the panel so that each sub-pixel can hold its state without being driven by the controller. The controller also can address sub-regions under the control of the application processor. The net effect is that the app can vary refresh rate and also update a small part of the screen while leaving the rest static. In Garmin smartwatches, this is used to switch between 1 Hz, 1/60 Hz, and a hybrid mode where the overall screen is 1/60 Hz and small part is updated at 1 Hz. E.g. the seconds digits may remain active while the rest of the screen is static. It also seems like they use more interesting sub-pixel arrangements. The limited color depth may involve different combinations of 1-bit sub-pixels rather than any cells driven into partially twisted states. I've seen diagrams claiming some white (unfiltered) and RGB filtered sub-pixels of different sizes.

wolrah 1y ago

> EInks advantage is that if you turn off power, the ink stays put. E-ink's other advantage is that it reads like paper. In a desktop context I could not possibly care less about the power consumption, but being able to read a forum thread, chat channel, HN discussion, etc. without a backlight would make my eyes very happy.

luqtas 1y ago
there's no evidence/meta-analysis pointing e-ink screen tiring eyes more/less than LCD
- wolrah 1y ago
  Is there any actual scientific study saying anything either way? I'm aware of a lot of anecdotal evidence in favor of e-ink displays being easier on the eyes than normal LCDs in some way, my own personal experience included, but I will happily admit I'm wrong if there are studies indicating otherwise. I like my Kindle and DIY e-ink weather display but I'm not religious about it. I wouldn't be shocked to find out it was just a weird placebo thing because it's different.
  - luqtas 1y ago
    i don't think there are much but i made my research a decade ago after realizing i was having a good time with my smartphone compared to my e-reader [1] suggests that LCD even increases processing speed compared to e-ink [0] https://pubmed.ncbi.nlm.nih.gov/22762257/ https://pubmed.ncbi.nlm.nih.gov/22762257/ [1] https://bop.unibe.ch/JEMR/article/view/2338/3534 https://bop.unibe.ch/JEMR/article/view/2338/3534 there's a study from Havard concluding "e-ink is 3 times better for eye health than LCD" but it feels rather dubious from the claims (blue light stressing more the retina... like i couldn't use a glass or apply a filter on my screen), light intensity (again...), in-vitro study and who funded the study (a great e-ink screen producer) -> https://sid.onlinelibrary.wiley.com/doi/10.1002/jsid.1191 https://sid.onlinelibrary.wiley.com/doi/10.1002/jsid.1191 i probably read hundred books since i sold my e-reader and moved to my smartphone. i really like having a single device. battery is fine. physical books with images still rocks but maybe becuse i don't have a tablet :)

m463 1y ago

Actually, the advantage is that it is reflective and works better in high ambient light.

maksimur 1y ago

I wonder if we could engineer a lighter ink

micheljansen 1y ago

For mobile devices that matters, but plenty of use cases for stationary displays, including desktops.

rldjbpin 1y ago

IANAE but won't e-ink at high refresh rates have the same benefit as OLED in terms of only refreshing what needs changing? perhaps in practical situations the power consumption should be lower than the worst-case scenario.

Aerroon 1y ago

So I guess an e-ink display would not be good with my book reading habits then. I will often scroll a few lines at a time and that sounds power expensive.

bee_rider 1y ago
It would still only need to refresh fast enough to keep up with your line reading rate, right? Couldn’t be much more than 1 fps.
- Aerroon 1y ago
  Oh, that's not what I was thinking about. I was thinking about its power efficiency coming from not being to update the screen. Scrolling would force a lot more updates on it.
carlosjobim 1y ago
You just have to read your books like you would read a book.

gdbsjjdn 1y ago

In my experience using e-ink readers (admittedly I have a Kobo, which may not be the state of the art), I would like to refresh the screen rapidly in bursts -navigating menus, flipping past an index - and then have a non-backlit screen with low power cost to show the same content for a while. In other words, a variable refresh rate. If you think of the refresh rate not as a constant frequency but as variable with user input, there are some cases where driving eink quickly in short bursts could make sense? It seems like this project offers a foundation for such a controller, where e-reader controllers are strictly optimizing for low refresh rates. E-ink is not going to be competitive for playing a video game or watching a video, but you can create a more responsive experience with less eye strain for typical tasks like marking up documents.

lucasacosta_ 1y ago
That sounds like the way to go. In terms of reading books (my normal usage of e-ink readers) you don't need 60hz when flipping a page, but it's a must when trying to use an app menu, or using Google Drive for example. Identifying when to increase the refresh rate may be a challenge but I can see it pretty doable for this kind of "limited" scenarios where you either read or navigate a storage app.
alex-a-soto 1y ago
Yes, that’s the mental model I’ve been working from. Variable refresh tied to user input makes a lot of sense: short bursts of speed for navigation or editing, then settling into a low-power static state. Part of the challenge is deciding what belongs in hardware and what should sit higher up in the OS or software stack. Hopefully, as more people get the kits and the community grows, we’ll be able to think through these questions together and explore where the right balance between hardware and software should be.

constantcrying 1y ago

It is not as easy as that. The nature of EInk displays allows them to be usable without a backlight LCDs need backlights constantly, any analysis which doesn't take this into account is irrelevant. In any case, it is not clear that, even if EInk Displays are somewhat worse in power consumption, they aren't a superior display technology.

JoelMcCracken 1y ago

So why do eink monitors with ac power supplies still have lower refresh rates?