LongPad: A touchpad using the entire area below the keyboard of a laptop computer

Abstract

In this paper, we explore the possibility of a long touchpad that utilizes the entire area below the keyboard of a laptop computer. An essential prerequisite for such a touchpad is a robust palm rejection method, which we satisfy using a proximity-sensing touchpad. We developed LongPad, a proximity-sensing optical touchpad that is as wide as a laptop keyboard, and implemented a palm rejection algorithm that utilizes proximity images from LongPad. In a user study conducted, we observed that LongPad rejected palm touches almost perfectly while participants were repeating typing and pointing tasks. We also summarize the new design space enabled by LongPad and demonstrate a few of the interaction techniques it facilitates.