Piezoelectrics Enable Displays to Provide Both High-Quality Audio and Touch Feedback

The first is with the components themselves. The speakers in your smartphone and the system that gives your finger feedback when you touch a virtual button may be relatively small, but they are still big enough to limit how thin our mobile devices can get. These little components are also delicate, as you may have learned if you have dropped your phone. And they require openings in the enclosure that can admit moisture or debris.