US Patent 11921958 Haptic interface

A haptic interface of the ‘mid-air’ type, including a control circuit, a plurality of ultrasonic transducers connected to the circuit, which includes a first set of transducers emitting at a first ultrasound carrier frequency and at least a second set of transducers emitting at a second ultrasound carrier frequency different from the first; the control circuit being configured for modulating the signals sent to the transducers in order to generate, with the ultrasound waves emitted by at least a part of the transducers of the first set, an acoustic pressure detectable by touch within at least a first focal region, and generate, with the ultrasound waves emitted by at least a part of the transducers of the second set, an acoustic pressure detectable by touch within at least a second focal region.