Polarity Effect in Electrovibration for Tactile Display

Abstract

Electrovibration is tactile sensation of an alternating potential between the human body and a smooth conducing surface when the skin slides over the surface and where the current is too small to stimulate sensory nerves directly. It has been proposed as a high-density tactile display method, for example to display pictographic information to persons who are blind. Previous models for the electrovibration transduction mechanism are based on a parallel-plate capacitor, in which the electrostatic force is insensitive to polarity. We present experimental data showing that electrovibratory perceptual sensitivity to positive pulses is less than that for negative or biphasic pulses, and propose that this disparity may be due to the asymmetric electrical properties of human skin. We furthermore propose using negative pulses for insulated tactile displays based on electrovibration because their sensory thresholds were found to be more stable than for waveforms incorporating positive pulses.

Design of a transparent tactile stimulator

“…To cope with these problems, one may use electrovibration effect instead of squeeze film air bearing [1], but it requires high voltages, a connection of the user to the ground, and this effect is very sensitive to skin conditions [7]. Takasaki et al [12] first introduced a transparent tactile device, based on squeeze film air bearing.…”

Skeletouch

“…Another recently relighted technology uses an electro-static effect [Kaczmarek et al 2006] [Bau et al 2010]. The electrodes are located under an insulator layer, with which the finger makes contact.…”

The Perception of Ultrasonic Square Reductions of Friction With Variable Sharpness and Duration

“…To improve upon this feedback method, solutions to modulate the finger-surface friction have been proposed in recent years. One such technique is electrovibration, which creates an electrostatic attraction between the finger and the actuated surface and increases the finger-surface friction [1], [2]. Another technique, ultrasonic lubrication [3] is able to reduce the finger-surface friction by generating a squeeze film effect and an intermittent contact with the surface [4]- [6] either through a stationary wave on the whole surface or through evanescent waves within a precise location [7].…”