A. Marcus (Ed.): DUXU 2014, Part II, LNCS 8518, pp. 606–614, 2014. © Springer International Publishing Switzerland 2014 Augmenting a Wearable Display with Skin Surface as an Expanded Input Area Masa Ogata 1 , Yuta Sugiura 2 , Yasutoshi Makino 3 , Masahiko Inami 2 , and Michita Imai 1 1 Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan 2 Graduate School of Media Design, Keio University, 4-1-1 Hiyoshi, Kohoku, Yokohama 223-8526, Japan 3 The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 Japan {ogata,michita}@ayu.ics.keio.ac.jp, y-sugiura@kmd.keio.ac.jp, yasutoshi_makino@ipc.i.u-tokyo.ac.jp, inami@inami.info Abstract. Wearable devices such as the wristwatch-type smart watch, are becoming smaller and easier to implement. However, user interaction using wearable displays is limited owing to the small display area. On larger displays such as tablet computers, the user has more space to interact with the device and present various inputs. A wearable device has a small display area, which clearly decreases its ability to read finger gestures. We propose an augmented wearable display to expand the user input area over the skin. A user can employ finger gestures on the skin to control a wearable display. The prototype device has been implemented using techniques that sense skin deformation by measuring the distance between the skin and the wearable (wristwatch-type) device. With this sensing technique, we show three types of input functions, and create input via the skin around the wearable display and the device. Keywords: Skin Deformation, Wearable Display, Photo reflectivity. 1 Introduction Owing to the recent miniaturization and performance improvement of handheld mobile devices, both users and suppliers have begun to focus on the possibilities of wearable devices that are smaller and more capable than those available a generation ago. Recent research and development has produced multiple watch-type wearable devices, including models that run on the Android OS. These devices have basic functions such as a clock, and other applications related to smartphones. In fact, wearable devices with small displays are suitable for obvious tasks such as checking time, reading news, or sending and receiving short text messages. However, when users want to control devices using familiar touch-based manipulation, and those devices have a limited ability to accept input, the convenience of being wearable is not useful for many users. Finger gestures have become familiar and acceptable for general interaction with mobile devices, and are suitable for providing users intuitive manipulation. However, if the display area is substantially smaller, the benefits of