A gui movement system by back-of-device interaction for one-handed operation on a large screen smartphone

The use of large screen smartphones has been increasing yearly. When people operate smartphones with one hand, several usability problems can occur due to the posture of the user’s hand when holding the device. Among those problems, a significant one we have noticed was that it is difficult to reach the top of the screen with thumb. In this paper, we propose a system to assist the one-handed operation of comparatively large smartphones by pulling down the GUI on the screen by back-of-device operation using one’s finger (excluding the thumb). In this study, we implemented the system with an application for iOS and a sensor module. After this, we conducted an experiment to investigate the performance and effectiveness of this system on usability by comparing it with Apple’s Reachability. Consequently, our system enables the participants to point more rapidly in the upper half area of screen than Reachability. On the other hand, the participants touched slower in the lower half area than Reachability. We will improve the usability of this system by using a pressure-sensitive touch panel instead of a photo-reflective sensor