Is it really "closely guarded", or "worst guarded"? Anyone with a logic analyser and a few hours can probably figure it out easily enough... and some have even gone beyond what the official controllers can do:
Certainly a number of drive waveforms and the basic concepts are presented. There are likely implementation subtleties or specific configurations that are not explicitly disclosed.
You can probably figure out a lot about both the implementation, and motivation by digging through the patents.
The patents disclose general categories of waveforms, but they leave out key details of exactly how the final results are achieved. Thus, the final waveform Performance is a combination of patent and trade secret.
Additionally, as others have posted, the waveforms vary for different panels, due to manufacturing variation, so reversing a single example won’t tell you much about how to drive a different panel.
A trade secret that can be reverse engineered by a tinkerer with an oscilloscope in an afternoon.
This is more or less the type of situation patents were invented for: a simple invention anyone can copy once it's invented, but difficult (I assume) to invent in the first place.
It's why I don't like most software patents, but why I think codecs, especially the modern ones, should be patentable. They're complicated engineering challenges requiring you to make numerous tradeoffs and I feel that just because the result is an algorithm doesn't mean that it shouldn't be patentable.
Other software patents I'm more dubious of, but I feel comfortable saying H.264 should be patentable.
Totally agree. However in many cases, the main technology is invented at universities with public funding. Also, codecs are a means of communication, and I don't think it should be patentable because it can cause problems once everybody settles on a single standard. See the MPEG nightmare, where professional cameras have a license attached to any movie shot with them.
Secrecy and patents are mutually exclusive. The deal you get with the patent is you disclose you invention so secrecy doesn't hinder progress too much and in exchange you get exclusivity.
You can measure samples of the waveform, but the tricky part is how the waveform changes with temperature and aging of the e-ink panel to produce minimal ghosting under all conditions.
That's a good machine learning problem. Point a camera at the thing as you change conditions and the waveform and let hill-climbing do the tuning for you.
You can buy fairly cheap displays from https://www.waveshare.com/ along with Raspberry Pi HATs and the PaperTTY project gives the power to do a partial refresh instead of full screen refresh on these screens. The waveforms are available in the Waveshare open source code and you can modify them as you will.
I am getting my screen next week and hoping to make my own little emacs only laptop using a Rpi Zero.
https://hackaday.io/project/11537-nekocal-an-e-ink-calendar/... (previously discussed at https://news.ycombinator.com/item?id=16140284 )
More research from others:
http://essentialscrap.com/eink/
https://news.ycombinator.com/item?id=11894613
https://www.eevblog.com/forum/microcontrollers/interfacing-e...