Wirelessly powered bistable display tags

Paper displays have a number of attractive properties, in par-ticular the ability to present visual information perpetually with no power source. However, they are not digitally up-datable or re-usable. Bistable display materials, such as e-paper, promise to enable displays with the best properties of both paper and electronic displays. However, rewriting a pixelated bistable display requires substantial energy, both for communication and for setting the pixel states. This paper describes a bistable display tag that, from an en-ergy standpoint, is capable of perpetual operation. A com-mercial off-the-shelf NFC-enabled phone generates RF sig-nals carrying both the information and energy necessary to update the display. After the update is complete, the display continues to present the information with no further power input. We present one example implementation, a compan-ion display for a mobile phone that can be used to capture and preserve a screenshot. We also discuss other potential applications of energy neutral bistable display tags