This nanotech dermal display is a designer concept, based on real nanoscience principles. Seattle-based designer Gina Miller, working together with nanotech populariser Robert A. Freitas Jr., describes the concept:
In his book Nanomedicine, Volume I: Basic Capabilities [available on the web at http://www.nanomedicine.com/NMI.htm ], Robert A. Freitas Jr. describes [in section 18.104.22.168 (page 204)] a “programmable dermal display” in which a population of about 3 billion display pixel robots would be permanently implanted a fraction of a mm under the surface of the skin, covering a rectangle 6 cm x 5 cm on the back of the hand. Photons emitted by these pixel bots would produce an image on the surface of the skin. This pixelbot array could be programmed to form any of many thousands of displays. Each display would be capable of two functions: (1) presenting to the user data received from the large population of medical bots that roam the user’s body; (2) conveying instructions from the user to that same large population of bots. The display could be activated or deactivated by finger tapping on the skin.