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Emerging virtual and augmented reality technologies can transform human activities in myriad domains, lending tangible, embodied form to digital data, services, and information. Haptic technologies will play a critical role in enabling human to touch and interact with the contents of these virtual environments. The immense variety of skilled manual tasks that humans perform in real environments are only possible through the coordination of touch sensation, perception, and movement that together comprise the haptic modality. Consequently, many research groups are vigorously investigating haptic technologies for virtual reality. A longstanding research goal in this area has been to create haptic interfaces that allow their users to touch and feel plausibly realistic virtual objects. In this progress report, the perspective on this unresolved research challenge is shared, guided by the observation that no technologies can even approximately match the capabilities of the human sense of touch. Factors that have it challenging to engineer haptic technologies for virtual reality, including the extraordinary spatial and temporal tactile acuity of the skin, and the complex interplay between continuum mechanics, haptic perception, and interaction are identified. The perspective on how these challenges may be overcome through convergent research on haptic perception, mechanics, electronics, and material technologies is presented.

 

Thermal perception is important in the experience of touching real objects, and thermal display devices are of growing interest for applications in virtual reality, medicine, and wearable technologies. In this paper, we designed a new thermal display, and investigated the perception of spatially varying thermal stimuli, including the thermal grill illusion. The latter is a perceptual effect in which a burning sensation is elicited in response to touching a surface composed of spatially juxtaposed warm and cool areas. Using a computer controlled thermal display, we present experiments in which we measured temporal correlates of the perception of spatially inhomogeneous stimuli, or thermal grills. We assessed the intensity of responses elicited by thermal grill stimuli with different temperature settings, and measured the response time until the onset of burning sensations. We found that thermal grills elicited highly stereotyped responses. The experimental results also indicated that as the temperature difference increases, the intensity increases monotonically, while the response time decreases monotonically. Consequently, perceived intensity was inversely correlated with response time. Under current physiological explanations, responses to thermal stimuli depend on tissue heating, neural processing, and the spatial distribution (or juxtaposition) of surface temperatures. The results of this study could help to inform models accounting for these factors, enabling new applications of the thermal grill illusion. 

Reconfigurable organic logic devices are promising candidates for next generations of efficient computing systems and adaptive electronics. Ideally, such devices would be of simple structure and design, be power efficient, and compatible with high‐throughput microfabrication techniques. This work reports an organic reconfigurable logic gate based on novel dual‐mode organic electrochemical transistors (OECTs), which employ a self‐doped conjugated polyelectrolyte as the active material, which then allows the transistors to operate in both depletion mode and enhancement mode. Furthermore, mode switching is accomplished by simply altering the polarity of the applied gate and drain voltages, which can be done on the fly. In contrast, achieving similar mode‐switching functionality with other organic transistors typically requires complex molecular design or multi‐device engineering. It in shown that dual‐mode functionality is enabled by the concurrent existence of anion doping and cation dedoping of the films. A device physics model that accurately describes the behavior of these transistors is developed. Finally, the utility of these dual‐mode transistors for implementing reconfigurable logic by fabricating a logic gate that may be switched between logic gates AND to NOR, and OR to NAND on the fly is demonstrated.