Sound revolution: ultra-slim and efficient speakers that adapt to any surface

A team of engineers at MIT (Massachusetts Institute of Technology) have developed a paper-thin speaker made from a flexible ultra-thin-film device with the potential to turn any rigid surface into a high-quality, low-power active sound source. The research, published in the IEEE Transactions of Industrial Electronics, shows that the manufacturing technique is relatively simple and can be scaled up to produce ultra-thin speakers large enough to cover the inside of a car or plane, or wallpaper a room.

Most thin-film speakers on the market are designed to be self-contained because the film must bend freely to produce sound. Placing these speakers on a surface would prevent vibration and hamper their ability to generate sound. However, the MIT team has solved this problem. Instead of the entire material vibrating, their design relies on tiny domes on top of a thin layer of piezoelectric material that vibrates individually. These domes are surrounded by spacer layers on the top and bottom of the film that protect them from the mounting surface while allowing them to vibrate freely. These spacer layers protect the domes from abrasion and impact during daily handling, adding durability to the speaker. At the same time, the speaker delivers high-quality, powerful sound using less electrical current than a conventional speaker.

The possibilities of using this technology are numerous and could revolutionize the sound industry according to the engineers: “We have the ability to precisely generate the mechanical movement of air by activating a physical surface that is scalable. The options for how to use this technology are limitless,” says Vladimir Bulović, Fariborz Maseeh Chair in Emerging Technology, leader of the Nanostructured and Organic Electronics Laboratory (ONE Lab), director of MIT.nano, and lead author of the paper.