Science Daily July 2, 2020
When a medium is rapidly heated and cooled, heat transfers to its surroundings as sound. A controllable source of this sound is realized through joule heating of thin, conductive films by an alternating current. Researchers in the UK show that arrays of these sources generate sound unique to this mechanism. From the sound alone, they spatially resolved current flow by varying the film geometry and electrical phase. Electrical coupling between sources creates its own distinctive sound that depends on the current flow direction, making it unusually sensitive to the interactions of multiple currents sharing the same space. By controlling the flow, a full phased array can be created from just a single film. Using heat to produce sound allows us to make speaker arrays smaller than ever before, make the speakers flexible and transparent. Potential applications include haptic feedback systems in smartphones and other wearables…read more. Open Access TECHNICAL ARTICLE