Perceived Depth and Roughness of Virtual Buttons With Touchscreens

With the rapidly increasing penetration of touchscreens in various application sectors, more sophisticated and configurable haptic effects can be rendered on touchscreens (e.g., buttons). In this paper, we presented a design process to instantiate a wide range of vibrotactile stimuli for rendering various virtual buttons on touchscreens. We study the perceived depth and roughness of rendered virtual buttons. There are two stages: the design of the drive signals and the main study. We generated and screened drive signals to render vibrotactile stimuli for virtual buttons through varying envelope shapes, superposition methods, compound waveform composition (CWC) types, durations, and frequencies. The results show that the perceived depth of virtual buttons can be very deep, and the perceived roughness can be very rough around the resonant frequency. Perceived depth and roughness decrease when the frequency increases or decreases from the resonant frequency. A longer duration of vibrotactile stimuli and adding pulse numbers could increase the perceived depth and roughness. Perceived depth and roughness have a similar trend with varying frequencies at a fixed duration.