A reader has just pointed me at a press release that E-ink released yesterday. It seems that Sony's new 13.3" writing slate (the one with the flexible screen) is using a screen made by E-ink.
They're calling the new screen tech Mobius. Instead of the glass panel used in many ereaders today, the Mobius screen uses a plastic backplane that is flexible and as a result is more resistant to impact.
This is a screen tech that Sony has been developing for some years, and now E-ink is going to make it. E-ink has the 13.3" size in production now, and they are also looking at using the Mobius tech to make other ereaders and signage.
Update: E-ink says that they can offer a higher resolution screen, but Sony didn't want to make it.
Sony's writing slate has a display resolution of 1200x1600, or about 150 ppi (pixels per inch). That is a higher pixel density than the screen on the laptop I am using at the moment, but it is also far less dense than the crispness that we have come to expect on mobile devices - even E-ink devices.
The Kindle Paperwhite, for example, comes in at 212 ppi, while the Kobo Aura sets the new standard at 300 ppi. And even the older ereaders like the Nook Glow have a screen with 166 ppi.
I think that most of the leading consumer gadget makers will look at the Mobius tech and pass on using it on smaller screens because they will choose higher resolution over ruggedness. But the tech might show up on rugged devices like sports, construction, and military equipment - markets where durability is valued more than screen resolution.
But even if it's not the sharpest screen on the market, 150 ppi is nothing to sneeze at. That is the same pixel density that PlasticLogic achieved with their flexible epaper display. PlasticLogic never had much luck getting their screen onto tablet/slate/ereaders, but they did almost release the Que, a 10.7" slate. And PlasticLogic has also made a limited number of educational slates in Russia.
150 ppi is also better than what Polymer Vision was able to produce. This dearly departed company had released a cellphone with a 5" foldable E-ink screen. It was called the Readius, and it had a screen resolution of 320x240 when it briefly hit the market in 2008. Due to financial problems Polymer Vision was never able to produce a second model, so it's not clear what screen resolution they managed to achieve.
P.S. My source just reminded me that LG developed a flexible 6" screen that had a resolution of 1024x768. But that screen does not appear to have had much market success. I know of only one ereader that used it (Wexler FlexOne) ever hitting the market, and of course there is the Earl Android tablet (not yet on the market). So perhaps there are production issues with high resolution flexible screens, but unfortunately that is not the kind of question that anyone will answer.
Thanks, commenter known only as Name!