Psychophysical Measurement of Multiple Tactile Sensations Using a Broadband Vibrotactile Display

To improve the amount of transmitted information via a sensory substitution system, we examined tactile perception characteristics of the index finger while presenting broadband vibrotactile stimuli. A pin-matrix tactile display composed of 12 piezoelectric bimorph actuators was used to elicit tactile sensations. The piezoelectric bimorph actuator of the display possesses flat frequency characteristics in the tactilely perceivable bandwidth of vibratory sensations. The actuator can therefore generate skin displacement patterns onto a fingertip surface in accordance with the waveform of the input voltage to the actuator. An open question of tactile sensations induced by multiple frequencies and waveforms was performed using the tactile display. A psychological scaling test of tactile sensations was conducted with the aim of transmitting voice quality information by tactile sensations. Most subjects perceived common changes of tactile sensations. This provides a guideline for the voice quality transmit function of tactile aids for the hearing impaired and other communication devices.