An interactive tactile graphics display

We have built and operated an interactive tactile graphics display based on 48 piezoelectric actuators assembled in a movable tactile output unit. The unit can be positioned at any location on a two dimensional surface to explore the structure of a virtual image. The virtual tactile display (VTD) can receive data either from a camera system or from a data base on a computer. Both static and dynamic patterns can be displayed. The maximum refresh rate of the tactile image is 20 Hz. This paper covers the technical description of an improved version of the virtual tactile display which takes into account all experience gained with an initial prototype. A short overview of the results obtained in tests done with 6 blind and 4 sighted subjects using the initial prototype shows the capacity of the underlying concept.