Oh conceptual design, how awesome thou art. This is the "Second Life Mobile Phone Concept" by Cho Sinhyung & Jeon Jungjae, a phone that employs both a lovely AMOLED screen in glorious full color when it's active, and an E-Ink display when it sits in standby mode. Juice saver deluxe! Furthermore, the degree of transparency in the screen shows the percentage of battery remaining. Fade away like you're Marty McFly. Futuristic.