摘要 |
An input apparatus has an interaction surface, an acoustic transmitter located adjacent the surface, an acoustic receiver located adjacent the surface and across the surface from the transmitter, and a processing environment. It is configured to transmit an acoustic signal(s) from the transmitter and to receive the signal or signals at the receiver. It detects the presence of an input object adjacent or touching the interaction surface by detecting an increase in the minimum time of flight, through air, of at least a part of the signal(s). |