US Patent 8743091 Acoustic multi-touch sensor panel

Sensing of multiple touches on a surface of a material is provided. A beamed acoustic wave traveling in a substantially linear path along the surface of the material is formed by a plurality of transducers, e.g., a phased array, coupled to the surface. One or more echoes of the acoustic wave caused by a corresponding one or more touches on the path are detected with a detector. The detector may include, for example, one or more of the transducers in the plurality of transducers. The surface can be scanned with a plurality of beamed acoustic waves using a variety of configurations, such as parallel beams, radially emanating beams, etc.