Air-Pulse Generating Device with Asymmetric Initial Deflection

An air-pulse generating device, comprising:

• a film structure comprising a flap pair, wherein the flap pair comprises a first flap and a second flap opposite to each other;
• wherein the flap pair operates at an ultrasonic frequency, such that the air-pulse generating device produces a plurality of air pulses at an ultrasonic pulse rate;
• wherein the flap pair performs a differential mode movement to form a virtual valve;
• wherein the virtual valve is closed during a time corresponding to a first reversal of a first flap movement of the first flap and a second reversal of a second flap movement of the second flap.

An air-pulse generating device, comprising:

• a film structure comprising a flap pair, wherein the flap pair comprises a first flap and a second flap opposite to each other;
• wherein the flap pair operates at an ultrasonic frequency, such that the air-pulse generating device produces a plurality of air pulses at an ultrasonic pulse rate;
• wherein the flap pair performs a differential mode movement to form a virtual valve;
• wherein the flap pair performs a common mode movement, to form an ultrasonic pressure variation;
• wherein a pressure variant frequency corresponds to the common mode movement and a valve driving frequency corresponds to the differential mode movement are the same.