Pure silicon, CMOS compatible, 120 dB from 10 mm².
High-fidelity sound, generated inside a silicon chip.
Meet our unique patented NED technology for in-ear MEMS micro speakers.
Video © Fraunhofer IPMS
A Novel Audio Transducer Technology
For the first time sound is generated inside a silicon chip! We replaced the conventional loudspeaker membrane with hundreds of moving beams. They use the chip’s volume instead of the surface.
Driven by electrostatic forces, no fancy materials are required. Widespread CMOS fabrication processes can be used. This makes our patented MEMS micro speaker design easy to scale for mass markets.
First Time: Sound Generation Inside a Silicon MEMS Chip
A multitude of sound generating beams are moving inside a silicon chip according to an audio signal. They are arranged between a top and a bottom wafer. The sound is released through openings in the bottom and the lid.
Each beam contains the “muscles” that drive it. That approach allows for an incredible variety of designs – of the individual beams and the entire chip.
Image © Fraunhofer IPMS
120 dB from only 10 mm²
Using the silicon chip’s volume minimizes its size and costs per device. Our goal is to achieve a sound pressure level of 120 dB with a chip area of only 10 mm². Our MEMS micro speakers have no outer moving parts and therefore even works without an additional package.
Crystal Clear Sound by Electrostatic Actuation
The sound generating beams consist of three electrodes. Between these electrodes, an electrostatic field causes a tiny movement. It is restricted to only 800 nm, which is one third of the gap between the electrodes. (A human hair’s diameter is roughly 75 times larger.)
Due to the beams’ curvy geometric shape, this minute movement is translated into the required deflection of the whole beam. We call this Nanoscopic Electrostatic Drive (NED). Each individual beam can only displace a small amount of air. The required sound pressure level is reached by the sheer number of beams in one chip.
Lower power consumption saves battery for new functionalities in in-ear devices
The small electrode gaps of around 2,5 µm allow for driving voltages well below 50V and electrical capacitance significantly below 1 nF. With a proprietary amplifier design and power management, we target a power consumption that stays below 3 mW.
Some of the best sounding headphones are based on electrostatic transducers. We want to enable this high-fidelity sound experience for all types of modern in-ear audio devices, such as TWS, hearables, in-ear monitors, and hearing-aids.