LCD screens project light on your face (and in your eyes). E-ink does not. And there's the whole sun thing (altough I rarely use my Kobo outside). I don't know about sleep and focus (I sleep easily and like a rock) but I can use my kobo without glasses, which I can only do for a short time with LCD.
Dumb question, but isn't light being project in our face the only way we can see things? Does it have something to do with the brightness of that light or the fact that it's direct that is bad?
I (non-expert) think that it’s the fact that it’s more about the brightness. And screens are really bright. And there’s the contrast with the surrounding environment. I’ve read that the brightness of the screen should be roughly equal to the amount of light reflected by a piece of white paper for ergonomics. E-ink is a surface illuminated by light while lcd are just light filtered and usually brighter.
