There is no backlight - it's an e-ink screen, that's the whole point.
For those who've never seen one, think of an old paperback book made on heavy grain paper - you know the slightly off whitish, rough textured stuff.
It's almost *exactly* like that.
And it's hard to overemphasis the "exactly". Genuinely is exactly like reading a book, so if you need to put light on a book, you'll need to put light on it.
They're fantastic for people who read a lot - battery life is well into days as the screen only uses power to change itself, once it's set it doesn't actually use any power a