Response Surface of Softness Perceived via Frictional Tactile Stimuli on Flat Touch-display

Abstract

An electrostatic frictional tactile display is used to present softness on a rigid flat-panel display. The display controlled the friction force of a finger sliding on it. However, the effects of representative stimulus parameters, those are, the finger’s sliding velocity and wavelength which determined the spatial change of friction on the panel, are unknown, whereas the low-frequency fluctuation of surface friction is known to be important for softness presentation. This study experimentally specified the response surface of subjective softness as a function of the stimulus wavelength and finger’s sliding velocity, involving ten participants. Consequently, the response surface was established, with a local maximum at the wavelength and sliding velocity of 10.55 mm and 198.6 mm/s, respectively. This stimulus condition was considered effective for the softness presentation.