An apparatus uses a transducer to produce vibration in the ultrasonic frequency range and in the audible frequency range. A membrane or cantilever structure is coupled to the transducer to produce acoustic waves. When the vibration is in the audible frequency range, the membrane structureworks like a conventional loudspeaker. When the vibration is in the ultrasonic frequency range, the ultrasonic signal is modulated byaudio signal for creating better directivity.The acoustic waves in the ultrasonic frequency range can reproduce directional audible sound due to the nonlinear interaction of ultrasonic waves in air.
申请公布号
WO2010034874(A1)
申请公布日期
2010.04.01
申请号
WO2009FI50630
申请日期
2009.07.17
申请人
NOKIA CORPORATION;CAI, CHENGUANG;XU, LIANGFENG;WANG, XIA;NURMINEN, JANI;SALO, ANTTI;OZCAN, KORAY