Originally Posted by HarryT
It's not so much knocks that will break an eInk screen as twisting forces. There's a very thin layer of glass underneath the outer plastic screen; that is very easily fractured if it's twisted.
I don't think that the outer layer you are referring to is plastic on my PRS-650, I think it's glass, though it possibly might be plastic on some earlier non-touch models.
The maker claims that the inner e-ink display layer can now be made "Flexible"
"E Ink displays are flexible and becoming more so every year. Flexibility doesn't mean you'll be able to roll up the screens and stuff them in your backpack, but is is key to making displays with larger screens light enough to hold it conveniently in one hand.
Flexible doesn't mean the display is floppy, it refers to its lightweight, shatterproof or rugged characteristics."
But there is no denying that cracked e-ink screens do remain a problem on virtually ALL e-ink e-book readers.
I would guess that, in order to improve readability and contrast, which is at a premium in e-reader screens, the thin e-ink layer is bonded right to the back of the screen bezel glass, so if you crack or even tweak the screen with too much force, you start breaking internal connections and it's toast.
Put your unprotected Kindle, Kobo, Nook, or Sony Reader in a gym bag or purse; banging around with a lot of other things; and you are begging for a cracked screen.
Or simply fall asleep while reading and crunch the screen under an elbow while rolling over.
So you have to avoid these kinds of situations where over stress or impact could crack your screen.
Glass is tough and scratch resistant, and it will put up with abuse up to a point, but then you go just a little farther, and CRUNCH, your screen is cracked.
When somebody does crack their screen, it's often the same sad story, "I don't know what happened! I didn't do any thing different. It just cracked!"