alt Hacker NewsThat's exactly it. I was a firmware engineer at reMarkable making the latest tablets.
We had some secret eink sauce (propriety waveforms) to get the high refresh rates and colour contrast without a full flashing screen reset, but even then you need to run longer maintenance refreshes occasionally.
Pixels are just vertical columns of viscous fluid with charged ink particles. A waveform is just voltage changes over time to these columns to shift the particles up and down. More black to the top = darker shade of grey. Colour (in the gallery display, at least) is the same, just with each CMY particle group having different charges and responses to different waveforms.
Every once in awhile this vertical column gets messy with loose particles distributed through it (ghosting, muddy contrast) so performing a hard rail-to-rail voltage reset forces all the particles up and then down, and gives you a clean slate.
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Out of interest, what (vaguely) is the amount of time you need between maintenance refreshes?
Interesting. Thanks for sharing.
I have a question, hope it's not too sensitive, how do you guy protect your secret waveform ? One with enough tool and determination can just measure voltage at pixel and reverse the whole thing, the chinese can do that in less than a week i bet.