Barnes & Noble on Thursday released a new Nook Simple Touch e-reader with a screen that lights up so that books can be read in the dark.
The Nook Simple Touch with GlowLight is aimed at people who want to read in bed before they fall asleep.
Barnes & Noble said it will "end the bedtime reading debate -- when you want to read and your partner wants to sleep."
It's a new twist in the development of e-ink screens, which have relied mostly on ambient light to brighten the screen. Some other devices have LCD screens, but they're hard to read in direct sunlight because of glare.
The lighting on the new Nook comes from small LED lights embedded just above the display. The device has a six-inch greyscale screen that retains its anti-glare characteristics in sunlight, Barnes & Noble said.
Users can illuminate the screen by tapping the surface and then control the level of brightness. The device can deliver a month of battery life with the glow light on, according to Barnes & Noble.
The company said the screen is a big advance over its existing e-readers and sets it apart from its main rival, Amazon.
The new e-reader has Wi-Fi and weighs less than 198 grams, making it lighter than the original Nook Simple Touch e-reader. It's priced at US$139 and will go on sale in the US in May. Details for international availability weren't available.