Japan Display Inc. have some very cool new LCD technology that embraces natural light in favor of the current backlight found in LCDs. The natural light will illuminate on-screen images, but in complete darkness they can't be viewed at all.
The way it works is a light control layer gathers light from the environment, and then reflects it back to the user. Monochrome images are produced by the liquid crystal shutter, combining that with filters to generate color images that look a little like paper.
There are limitations, though, with the 7-inch prototype ready for mass production sporting a 1024x768 resolution but only covers a slither of the NTSC color gamut, 5% to be precise. There's a second prototype that is still being worked on, which covers much more of the NTSC color gamut, ramping it up to 36%. This display comes with a lower resolution of 1024x576 and is less reflective, offering dimmer images.
Both screens have 30:1 contrast ratios and only consume 3 milliwatts when producing images. The refresh rate should be fine for video, too.