Tactile display for 2-D and 3-D shape expression using SMA micro actuators

Tactile display which displays character and graphic information dynamically from computer by making pins array up and down has been developed. Shape Memory Alloy (SMA) micro-coil actuators contract and make the pins up and down when an electrical current is supplied. Magnetic material tube is attached to each pin and a permanent magnet fixes position of the pins up or down. Electrical consumption is low because the current is supplied only when the pins move. A 2-D tactile display which has 100 (10 x 10) pins array has been developed and successfully operated. The tactile information were displayed sequentially every 0.3 second and the pins were latched at 0.1 N by magnetic force. The pins are arranged at a pitch of 2.5 mm and move 2 mm up and down individually. In order to present the tactile information accurately, narrower pin pitch of the tactile display is preferable. A module for tactile display with a pin pitch of 1.27 mm has been fabricated and successfully operated. A multi-step magnetic latch has been developed for a 3-D tactile display. By using these mechanisms, large displacement and accurate positioning of the pin for 3-D expression can be realized.