Designing a non-contact wearable tactile display using airflows
Jaeyeon Lee and Geehyuk Lee
Traditional wearable tactile displays, such as vibrotactile or electrotactile displays, transfer tactile stimulations through a physical contact between the skin and the tactors. Moreover, all of the tactors should be mounted firmly on the skin to transfer spatiotemporal patterns. The firm and prolonged contact by a wearable object can be a source of discomfort in the aspect of moisture transport, constriction, pressure, etc. In fact, wearable accessories like bracelets or watches are not usually worn tightly as people tend to avoid a firm contact. We recognized that a contactless, distance tolerant feature would be an important requirement for the future wearable tactile display.
We selected an airflow-based tactile stimulation method among other non-contact stimulation options because it allows a smaller form factor, has fewer safety concerns, and provides a natural sensation. An airflow-based tactile display, however, required us to start from basic psychophysical studies. The sensation of wind involves multiple sensory receptors which have different characteristics, e.g. conducting velocity, and therefore findings from vibrotactile display studies could not be applied to the design of an airflow tactile display. In addition, most of the prior studies on airflow-based tactile displays do not provide empirical data on tactile perception of an airflow that may be applicable to the context of wearable computing applications.
We conducted a series of psychophysical experiments to produce empirical data such as intensity thresholds, temporal thresholds, and spatial thresholds for airflow stimuli to understand the human perception of airflows. Based on the empirical data, we designed a 2-d airflow display, and evaluated its information transfer efficiency in comparison with a traditional vibrotactile display. The result showed that the non-contact tactile display using airflows can be as efficient as a vibrotactile one.
In addition to the information transfer efficiency, the airflow-based display received unique and positive user feedback about tactile experiences, which are in contrast with that of the vibrotactile display. We expect that the airflow tactile display will be useful not only for transferring spatiotemporal patterns but also delivering emotions in the context of wearable applications and electronic clothing. In particular, we expect that the current study on human airflow perception may be continued to support the design of immersive tactile feedback in virtual reality environments.
- Designing a Non-contact Wearable Tactile Display Using Airflows
Jaeyeon Lee and Geehyuk Lee, UIST 2016. [acm dl] [slides]