Joseph K. Lee recently posted on the web a phone design called Sign, a device that uses sun power to charge the battery up to 80%. The design of the Sign is pretty futuristic, as you can see in the images below. The handset has a concealed screen, based on transparent OLED technology.
Numbers, text and icons will be appear when required, since the keypad area is also concealed and “triggered” by the user’s actions. A solar panel is placed at the back of the device, giving it the needed energy. This is a very sleek phone, one that’s both eco friendly and elegant, plus it can be a fashion accessory, since no one would know it’s a phone, with its hidden display.