Curious.

See the microwatts of power that Sharps MemoryLCD displays have. They often beat comparable EInk screens in power draw.

  > Ghosting depends on the mode you're using and the content.

  >> Is it clear enough to be used white-on-black?
  > Yes

There are refresh modes now which are very good at partial updates.

Mysterious future Tech#3 will break the rules. OLED for example uses far less power on black pixels. It's just different.

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.

https://www.youtube.com/live/okjJURIejIY?feature=shared&t=24...

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.

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.

> 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.

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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).

For text updates, where there's literally a cursor which moves at typing speeds, update frequency is quite low. Where you're updating or paging through documents, paginated navigation (where the whole screen refreshes at once, then remains unchanged for several seconds to minutes or longer) is quite efficient.

I went through that and then bought a Carta 1200 display BOOX 13.9 and it's amazing. Black and white only, but the contrast makes the device usable.

If you know you won't return the device, get it on their website because they'll give you extra pen tips and a case. I got mine on Amazon, so I missed out on the extra stuff because of my return experience.