Development of tactile katakana delivery device and investigation on characteristics of katakana recognition by active touch

Braille is one of the few writing systems that use tactile perception. The system is widely used by the blind to read and write. However, Braille is difficult to learn for persons with acquired blindness, especially for the elderly. Therefore, the aim of the present study was to design a tactile Japanese Katakana presentation device for the investigation of characteristics of tactile Katakana recognition. The device consists of a disk for tactile Katakana patterns, a force sensor unit for force measurement when subjects' fingers touch the tactile patterns, and an ultrasonic motor for tactile patterns presentation. Using the ultrasonic motor, the device presents characters to subjects quickly and automatically. Furthermore, the device has a big advantage that subjects are only required to move their fingers up and down, without any big submovements. An experiment was conducted using the device to test tactile recognition of 46 Katakana characters in native Japanese speakers with normal vision. Ten healthy right-handed male volunteers consented to participate in this experiment. Successful tactile Katakana recognition was higher than 78% (+14.4%) for these young subjects.