Development of thermal displays for haptic interfaces

Abstract

This thesis studied the effect of different stimulus parameters on the thermal response of the skin. A set of thermal patterns, known as thermal icons, was presented to participants using a thermal display mounted on the hand. The thermal responses of the skin were studied to understand which features of the thermal stimuli were important and could be perceived by users. The effectiveness of these patterns was evaluated for applications involving hand-held and wearable thermal devices. In the first series of experiments, a set of six thermal icons was developed and presented on the thenar eminence and the fingertips. The second experiment was conducted on the wrist with a revised set of thermal icons which had a shorter duration and were presented relative to each participant's baseline skin temperature. The information transfer (IT) values for the thermal icons presented on the wrist-mounted thermal display demonstrated that the information processing capabilities of the thermal sensory system may rival those achieved with vibrotactile inputs. To date, thermal icon studies have only used the temporal properties of stimuli and not the spatial properties. A set of two experiments was conducted to examine how the spatial and temporal properties of thermal stimuli interact. The results showed that the temporal properties of thermal stimulation can influence the perceived location of a thermal stimulus. This space-time dependency for the thermal sensory system provides an extra dimension to use to present information in a thermal display and potentially could result in a display that functionally has a higher spatial resolution than the number of thermal elements would indicate.