Murata Manufacturing Co., Ltd.

Shuho Saito

Kazuaki Yamamoto

Hiroyuki Inami

Toshiaki Yamashita

Isao Okada

Osamu Segawa

A piezoelectric electro-acoustic transducer has a substantially decreased resonant frequency without having to modify the size of a piezoelectric diaphragm or the shape of casing members used therein. The piezoelectric electro-acoustic transducer has a piezoelectric diaphragm including a metal plate and a piezoelectric ceramic disc disposed on one surface of the metal plate, wherein the piezoelectric diaphragm is to be supported at its periphery. A plurality of projections are specifically provided for stress transmission suppression at the periphery of the piezoelectric diaphragm in order to suppress or eliminate occurrence of circumferential transmission of a stress at the periphery during activation of the transducer.

Piezoelectric electro-acoustic transducer

A piezoelectric electro-acoustic transducer eliminates a negative influence caused by metal terminals upon the sound pressure and resonant frequency characteristics even when size and thickness reduction of the transducer are made. The transducer includes a piezoelectric diaphragm which includes a piezoelectric ceramic plate and a metal plate stored in a casing. The transducer also includes metal terminals in contact with the piezoelectric diaphragm and extending to the outside of the casing. The modulus of elasticity X of one metal terminal is specifically determined to be within a range defined by: ##EQU1## where E (N/m.sup.3) is the Young's modulus of one metal terminal in contact with a piezoelectric element, b (mm) is the width of part of the metal terminal extending from the inside of the casing to the outside thereof, h (mm) is the thickness of the metal terminal, and L (mm) is the length of the metal terminal.

Reduced size electro-acoustic transducer with improved terminal

A piezoelectric buzzer includes a piezoelectric diaphragm stored in a case having a case body and a back cover, and a pair of metal terminals which are electrically connected to the piezoelectric diaphragm and drawn out from the back cover. The metal terminals have terminal drawing portions, terminal fixing portions which are arranged along an inner surface of the back cover, and connecting portions which are bent from inner ends of the terminal fixing portions so that the bent portions are substantially U-shaped as viewed from above while forward ends thereof are separated from the inner surface of the back cover and brought into contact with the piezoelectric diaphragm.

Growing community of inventors

Toyama, Japan

Shuho Saito