Experimental Evaluation of Tactile Patterns over Frictional Surface on Mobile Phones

Tactile displays1 have been widely used in information transfer through various tactile patterns on mobile devices. The fundamental consideration in designing tactile interactions is intuitive tactile feedback patterns that convey information. This study investigates the user perception of various tactile stimuli patterns over frictional surface on mobile phones in terms of strong feedback. We designed 36 different tactile patterns with a combination of different signal lengths (w1 = 0.2-3.2 mm) and intervals (w2 = 0.2-3.2 mm) of frictional feedbacks. These parameters covered most cases in the tactile pattern design for a mobile phone. Using these stimuli, we presented 666 pairs of comparisons to 50 participants who would distinguish whether the stimuli in each pair were similar or different. The results indicated the dense patterns in which smaller values of w1 and w2 conveyed stronger tactile feedback and quick distinguish time to users. Meanwhile, the denser tactile patterns had significant differences, which suggests that users can easily distinguish different strong tactile patterns even when these patterns appeared simultaneously. The results of this study can be used as a reference to design tactons, obtain non-visual information, or encode tactile language.