SMALL ULTRASOUND DEVICE WITH ACOUSTIC DIRECTIVITY BASED ON PIEZOELECTRIC ELEMENT

The present invention relates to a small ultrasound device with acoustic directivity based on a piezoelectric element and, more particularly, to a small ultrasound device with acoustic directivity based on a piezoelectric element which comprises an acoustic signal modulation device to modulate an acoustic signal, which is output from an acoustic signal generator for outputting voice and music signals, to an ultrasound signal and to output the modulated signal; and an earphone having a piezoelectric element connected to the acoustic signal modulation device and focusing the acoustic signal on the inside of a user′s ear, wherein the center of the piezoelectric element of the earphone is recessed inward to have the same focusing point. According to the device of the present invention, high receiving sensitivity can be obtained with a minimum volume increase, and minimization of acoustic signals leaking to the outside, which is an advantage of a kernel type earphone, can be obtained while taking the form of an open earphone. The device of the present invention can be usefully used indoors and outdoors due to hearing loss prevention, high receiving sensitivity, and minimum ambient noise generation can be applied to a hands-free earphone for a mobile phone or a music earphone and a headphone.