PopSLATE introduced an e-ink display case for iPhone 5, 5S and iPhone 6. Priced at $129, this case has an essential 2nd screen at the rear which can display pictures, notes, text, etc without using any battery. You can display Full size images, apps, data, appointments, etc on always on e-ink display from gallery, Instagram, or camera. It remains there until you want o change the display. As said, the e-ink display wont take any charge, while it takes very little charge while changing the image.
popSLATE iPhone case is now available for pre-order from official popSLATE website at the price of $129. They will start shipping it from April 21.