Since all most soft wares are using GUI (Graphical User Interface), users have to follow a mouse pointer on a computer screen by their eyes to push bottoms. This work becomes a burden for not only elder peoples but also average peoples. If the users can feel convex portion of a bottom presented on the computer screen, they can push the bottom precisely. The authors expect tactile information assists the manipulation of the mouse pointer. In the present paper, the authors developed a tactile display for enhancing precision of pointing position of the mouse. The tactile display has 4-time-6 of stimulus pins using piezoelectric bimorph actuators. First of all, three kinds of tactile displays of which distances of two adjacent stimulus pins were 1.2, 1.9 and 2.4 mm (they were called low, medium and high density displays, respectively) were tested to obtain an optimal distance between two adjacent stimulus pins. Since it is found that percentage of correct answer for judgment of simple virtual shapes such as a circle, a triangle and a square is the highest in the case of using the medium density display, fusion tests were performed using the medium density display. In the fusion tests, the human subjects traced edges of the virtual shapes by using only their eyes and by using both of their eyes and tact. The human subjects found easily straight edges included in the virtual shapes by assistance of tactile sensation because average deviation from the desired edges using fusion of vision and tact decreases comparing with the average deviation using only vision. But the difference between using only eyes and using both of eyes and tact are very small because for the present human subject this tracing was easy work. Therefore, more sophisticated experiments should be conducted using elder subject or not average subjects who are not familiar with mouse manipulation.
