Character Reading via Stylus Reproducing Normal Handwriting Motion.

In this paper, we report a method of intuitively transmitting symbolic information to untrained users via only their hands, without using any visual or auditory cues. In this simple concept, three-dimensional letter trajectories are presented to the user's hand via a stylus which is mechanically manipulated. In experiments, participants were able to read 14 mm-high lower-case letters displayed at a rate of one letter per second with an accuracy rate of 71.9 percent in their first trials, which improved to 91.3 percent after a 5-minute training period. These results showed small individual differences among participants (standard deviation of 12.7 percent in the first trials and 6.7 percent after training). We also found that this accuracy was still retained to a high level (85.1 percent, with SD of 8.2 percent) even when the letters were reduced to a height of 7 mm. Thus, we revealed that sighted adults potentially possess the ability to read small letters accurately at normal writing speed using their hands.

Sharp Tactile Line Presentation Using Edge Stimulation Method.

We provide supplemental data to a vibrator array tactile display, as well as additional data for application of the edge stimulation (ES) method proposed in our previous study. By vibrating two surfaces in different phases and touching their boundary, a strong continuous line sensation, not on the vibrators themselves, but along the boundary, is obtained. This vibrotactile edge is suitable for presenting virtual lines, areas, and shapes on a rigid flat surface. We investigated the fundamental performance of the ES method through psychophysical experiments. The effects on the vibrotactile detection thresholds were investigated for three mechanical parameters, i.e., the vibratory frequency, the phase difference between the vibrations, and the gap distance between adjoining vibratory surfaces. Two-line discrimination thresholds for lines presented by the ES method were also determined. We found that the detection thresholds under the ES method was lower than 10 um even at the low frequencies (lower than 50 Hz), which is significantly lower than that under simply touching to a single vibratory surface. A comparison of the perceived widths revealed that the ES method provides a more localized tactile image than a single-pin vibrator or a flat-top vibrator. A 3 X 3 vibrator array display was developed using the ES method based on the properties obtained from the experiments. Seven categories of display patterns were presented with the ES array display and the participants' responses matched at 95 percent.