Evaluation of Size and Spacing of Buttons in Consideration of Contact Angle of Forefinger in Tablet Terminal with Touch-sensitive Screen

Abstract

The portability of touch-sensitive screen tablets provides high usability under various circumstances, and such tablets are increasingly utilized in the education and other fields. Meanwhile, the design of the graphical user interface (GUI) of such tablets requires careful consideration in order not to lose tablet operability in such diverse situations. In this study, we conduct an experiment to investigate the effect that touch-sensitive screen button size and spacing have on operability, while considering the influence of the angle that the forefinger makes when touching the screen. As a result, we could determine the conditions required for the size and spacing of buttons to allow fast and accurate operation independent of contact angle. Furthermore, we could reveal the relationship between contact angle and area, and investigate the impact of the contact angle when touching smaller buttons.