Smart Films Facilitate Human-Computer Interaction, Connect the Physical Hand to the Virtual World

A new sensory film developed at Saarland University can establish a direct connection between the virtual and physical worlds, communicating between the body and a computer to provide gesture recognition and send tactile signals. The research team, led by professor Stefan Seelecke, achieved this new level of connection between material and virtual realms through the use of a smart silicone film, essentially creating an adaptable sensory organ.

If integrated into touchscreen displays, the technology is able to create the sensation of a tactile button or slider on a flat glass display, bringing a new dimension to touch screen interactions. The polymer film changes shape to create the feeling of a raised button, which can be used to navigate a page or enter data. This can create more user-friendly interfaces; users can be prompted to respond when they feel a pulse or vibration, or they can be assured their response is successful by the slight resistance of a button or switch being pressed.

The film also has a possible use case as a liner for clothing, where it could act as a tactile human-machine interface. If used to line a glove, the film could track the movement of a user’s hand and fingers, providing gesture recognition. Seelecke’s team envisions the high-tech film as an integrated part of an Industry 4.0 environment, allowing assemblies operators to control processes via gesture, and providing tactile feedback to the operator’s motions to help avoid potentially costly mistakes.

The specially prepared smart silicon films are highly flexible and can be powered by the simple application of an electric current. An electrically conducted layer is printed onto each side to create a dielectric elastomer. When voltage is applied, the two electrodes attract each other, compressing the polymer and ultimately altering its electrical capacitance. So when a user wearing the film bends a finger, the film stretches, and the distortion causes this change in capacitance. Specific capacitance values then indicate specific positions, and a sequence of values represents the path taken. Altering the applied electric field can also cause the film to pulse, or deform into a desired shape, or oscillate or flex at the desired frequency.

Seelecke’s team is presently at work on a number of research projects aimed at interconnecting the described film-based systems so they can work collectively. This requires further work to impart new capabilities to surfaces and interfaces, which requires further miniaturization of the technology. The current dielectric elastomer film design, however, is lightweight, flexible, quiet, energy-efficient, and manufacturing is cost-effective.