Sharp tactile line presentation array using edge stimulation method

We report on a tactile shape presentation display that has a rigid plane for a surface and can present highly localized tactile stimuli using small vibrotactile stimuli. We have proposed an edge stimulation (ES) method that can present sharp tactile sensation along the boundary edge of vibratory surfaces. The basic concept is to use the ES method for shape presentation. The ES method allows the tactile display surface to be a flat plane; it can be mounted on a flat surface of any devices and can project images on this surface. The ES method uses low-frequency and small-amplitude vibrations that achieves low power actuation. Previously, we have developed an edge stimulation device (ES device) with voice coil actuators in 2×2 array and examined the concept of the ES method for shape presentation, though it was low rigidity (display surface was easy to be bent) and not capable for various shape presentation. In this study, we developed 3×3 array shape presentation display with rigid piezo-vibrators taking advantage of ES method. Psychophysical experiment on detection thresholds for vibratory stimuli demonstrated the display can make 5 μm at 30 Hz vibration perceivable, even though they normally require a 30 μm amplitude for simple vibrations. In the shape recognition test results, users correctly scored of 96 % for 8 patterns discrimination tasks.