This tech is still so extremely cool to me. https://en.wikipedia.org/wiki/OLPC_XO#Display
The OLPC-XO 1.0 had a specialized LCD display which could act in a 200dpi e-paper like monochrome mode if you turned off the backlight, or it could use a crazy diffraction grating with the backlight to provide one color per pixel to work as a color display. I so very wish that this had caught on more, especially with modern LCD/plastics tech. Color mode wouldn't be very sharp, but you could use it in bright sunlight.