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The article mentions turning off the display to avoid ghosting and links to an article about screen burn in; it was my understanding that e-ink displays do not

The article mentions turning off the display to avoid ghosting and links to an article about screen burn in; it was my understanding that e-ink displays do not suffer burn in? I was under the impression that e-ink ghosting is simply due to an incomplete refresh of the display (since this causes a flash and is time consuming)? EDIT: Interestingly the datasheet for the component used does indeed mention this; does anyone have any insight here?

reom_tobit 6y ago
Due to the design of the screens (small capsules containing charged particles that move back and forth to create either black or white) the capsules can retain the charge that is passed through them if not cycled correctly. This will cause the particles within to stay in whatever side of the capsule they were last in, essentially causing a dead “pixel”. If this happens across as a whole image like a logo or text, it’ll permanently burn in. This is solved by some flashing between colours, hence why the screens take so long to refresh. Up for more detailed info myself though!
- Polylactic_acid 6y ago
  "Turning off" the screen seems like an invalid concept as the screen has no "off" state, white pixels are just as much off as black. Seems like all you need to do here is to just blink the screen every now and then. Even one blink cycle per day should be enough since ereaders usually go longer than that and are just fine.
  - reom_tobit 6y ago
    I believe the danger is not necessarily when you are leaving the capsule in one state or another for a long period of time, I believe it is more to do with a transition. So if you’re going from black -> black you need to cycle to white to ensure you don’t burn the black in. I’m not an expert though I’ve just faffed around with these displays myself a bit. The datasheets always err on the side of caution, I managed to get maybe 3fps out of mine, but that induced a lot of ghosting. I should try to get back to that project tbh.
    - Polylactic_acid 6y ago
      Interesting stuff. I know my old ereader would flash the whole screen black and then white on each page flip. I'm actually really interested in creating a little dashboard that sits under my monitor so I can look down and see some important stats like if there are any peer reviews waiting on me and stuff like that.
      - reom_tobit 6y ago
        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 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 https://youtu.be/MsbiO8EAsGw
userbinator 6y ago
I believe this (along with the other warning to not leave the display on because the high voltage may cause degradation) is either a specific characteristic of colour e-ink or the effect of "cost down optimisations" that affect reliability; ghosting is just due to the fact that not all the particles move at exactly the same rate, but I've never heard of burn-in either. Then again, the last time I looked into detail on e-ink was around when someone figured out how to drive cheap Kindle displays without the proprietary controller (http://essentialscrap.com/eink/ http://essentialscrap.com/eink/ ), and those could be refreshed as slowly as desired, even "human" speeds.

reom_tobit 6y ago

Due to the design of the screens (small capsules containing charged particles that move back and forth to create either black or white) the capsules can retain the charge that is passed through them if not cycled correctly. This will cause the particles within to stay in whatever side of the capsule they were last in, essentially causing a dead “pixel”. If this happens across as a whole image like a logo or text, it’ll permanently burn in. This is solved by some flashing between colours, hence why the screens take so long to refresh. Up for more detailed info myself though!

Polylactic_acid 6y ago
"Turning off" the screen seems like an invalid concept as the screen has no "off" state, white pixels are just as much off as black. Seems like all you need to do here is to just blink the screen every now and then. Even one blink cycle per day should be enough since ereaders usually go longer than that and are just fine.
- reom_tobit 6y ago
  I believe the danger is not necessarily when you are leaving the capsule in one state or another for a long period of time, I believe it is more to do with a transition. So if you’re going from black -> black you need to cycle to white to ensure you don’t burn the black in. I’m not an expert though I’ve just faffed around with these displays myself a bit. The datasheets always err on the side of caution, I managed to get maybe 3fps out of mine, but that induced a lot of ghosting. I should try to get back to that project tbh.
  - Polylactic_acid 6y ago
    Interesting stuff. I know my old ereader would flash the whole screen black and then white on each page flip. I'm actually really interested in creating a little dashboard that sits under my monitor so I can look down and see some important stats like if there are any peer reviews waiting on me and stuff like that.
    - reom_tobit 6y ago
      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 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 https://youtu.be/MsbiO8EAsGw

userbinator 6y ago

I believe this (along with the other warning to not leave the display on because the high voltage may cause degradation) is either a specific characteristic of colour e-ink or the effect of "cost down optimisations" that affect reliability; ghosting is just due to the fact that not all the particles move at exactly the same rate, but I've never heard of burn-in either. Then again, the last time I looked into detail on e-ink was around when someone figured out how to drive cheap Kindle displays without the proprietary controller (http://essentialscrap.com/eink/ http://essentialscrap.com/eink/ ), and those could be refreshed as slowly as desired, even "human" speeds.