Mr Andrea Rusconi-Clerici, CTO & Co-founder – Usound Topic: MEMS Micro Speakers Challenges, Technology and Applications
USound is challenging the status quo of the $10B micro-acoustic market with a silicon MEMS micro speaker technology which has great potential, triggering comparable disrupting dynamics as for MEMS microphones and LEDs. We develop and market audio solutions in the field of micro-acoustics, in particular, wired and wireless earphones, AR glasses, wearables, VR/Gaming headphones, and portable consumer devices. Compared to micro speakers based on voice coil, piezo MEMS is superior in three categories: sound quality, form factor, system integration.
The biggest challenge in generating high sound pressure levels in a tiny form factor is to be able to generate large forces and elongations in a linear way. This has always been an obstacle for MEMS technologies. USound has leveraged the advent of new materials – in particular, thin film piezoceramics with high piezo coefficients – to break the barrier which previously challenged MEMS micro speakers. PZT can generate enough energy per unit area and thus mechanical force and elongation to compete with standard voice coil transducers. The MEMS motor is realized on silicon using multiple piezoelectric actuators connected together to realize a precise vertical out-of-plane movement. The piezo linear motor is faster and more precise than traditional magnetic coil technology, and for earphones, this produces deep and precise bass and crisp and clear treble with a single, extremely small transducer. Since PZT consumes 95% of reactive power, a patented energy recovery loop is transferring more than 50% of the energy back to the system making these devices extremely low power. And because USound’s micro speakers are based on planar technology, we can produce outstanding audio quality in a very small form factor.