Although today's earbuds may seem fairly small, they're limited in form and function by the fact that their speakers require membranes and magnets. A new prototype microspeaker overcomes those limitations, potentially providing more uses for in-ear headphones.
The flat, square, chip-format Nanoscopic Electrostatic Drive (NED) microspeaker is being developed by German startup Arioso Systems, a spinoff of the larger Fraunhofer Institute for Photonic Microsystems. It measures just 10 to 20 square millimeters, and is made entirely of silicon.
Inside of the microspeaker is an array of tiny flexible beams, each one just 20 micrometers in length. When the voltage of an audio signal is applied to the device, it causes those beams to repeatedly bend toward one another. As they do so, they force air out of small openings in the top and bottom of the device. That pumped air produces pressure fluctuations in the ear, which are perceived as sound.
Not only is the NED microspeaker considerably smaller than conventional models, but because it incorporates no outer moving parts, it should use much less battery power. It also ought to be cheaper and easier to manufacture, utilizing conventional production techniques.
Additionally, by freeing up space inside earbuds and requiring less power to produce sound, the technology could allow new functions to be packed into them. Those functions might include instantaneous language translation, health-monitoring features, or the ability to pay for purchases using voice commands.
The NED tech could also be incorporated into smaller, better-performing hearing aids.
Sources: Fraunhofer, Arioso Systems