E-paper requires a powerful burst of... erm... power... to change all of those pixels and refresh the screen. LCD on the other hand requires constant power but very little power to change pixels.

So there's a break-even point where E-paper is better. And that break-even is like... 15 minutes to an hour before E-paper is actually more power-efficient. And besides, LCD require less voltage (E-paper requires an inductor boost converter to reach the high levels of voltage needed to change the pixels) and has a simpler circuit.

"Standard" LCD is like 1mA though, and E-paper looks like its superior. The particular thing about "Sharp Memory-LCDs" is that they're a particularly low-power implementation, measured in microAmps of current usage.

So anyone out there, thinking of a small-screen project. Remember, smart-watches use LCD-screens for a reason.

https://www.digikey.com/en/products/detail/sharp-microelectronics/LS013B7DH03/5300387

Rumor this is the model for the incredibly low power "Pebble" smartwatch. I've never been able to verify the rumor though.

Whatever the rumors are, the specs of 50uW (microwatts) of power are incredible, and easily beat out E-ink screens in many circumstances. With all the benefits of the faster, near instant, response times you expect from LCD.

[–] minnix@lemux.minnix.dev 1 points 2 years ago

For some reason I never even considered using these little LCDs. The power consumption requirements make sense now that I think about all of the little thermometers and digital watches I see them on that seem to last forever.