In this lawsuit, Research Frontiers asserts infringement by the named defendants of United States Patent No. 6,606,185, entitled “SPD Films and Light Valves Comprising Liquid Suspensions of Heat-Reflective Particles of Mixed Metal Oxides and Methods of Making Such Particles,” and United States Patent No. 5,463,491, entitled “Light Valve Employing a Film Comprising an Encapsulated Liquid Suspension, and Method of Making Such Film.”
You can find the patents here and here. I skimmed the filings, and the technical details describe a technology that is so different from what I know of E-ink's screen tech that it's not clear to me how E-ink's screen tech infringes (or even if the tech infringes at all).
Other details are easier to explain, though. For example, E-ink's customers are being sued for contributory infringement (definition). This lawsuit is based on the theory that Amazon, B&N, and Sony bought screens from E-ink knowing that the screens infringed on the patents.
Or at least that is what Research Frontiers would have you believe; this also has the appearance of a troll going after the deepest pockets. (Why Rakuten/Kobo was left out, I do not know. Perhaps they settled.)
E-ink reported revenues of close to 900 million USD last year, with a gross profit of around 93 million USD (according to Bloomberg). The revenue is down from a peak of 1.3 billion USD in 2011.
I unfortunately don't have any first hand knowledge of whether this lawsuit has any merit, so at this point I will invite comment from anyone in the screen tech industry.
But one detail I can provide is that this lawsuit isn't as newsworthy as it might appear. This type of lawsuit is so common in tech that it is almost background noise for the major tech companies like Amazon, Google, Yahoo, etc. Check out the 10-k filings for those companies and you'll find boilerplate mentions of being sued for patent infringement. In fact, this is so common that I think Amazon is the only one that even lists the ongoing lawsuits any more.
image by saschapohflepp