JPS57181297A - Electroacoustic transducer - Google Patents

Abstract

PURPOSE:To permit a plane diaphragm to sound by energizing it by an upper and a lower thin film by forming space rooms which are recessed inwardly and partitioned by dividing plate part at symmetric position of the upper and lower surfaces of the diaphragm, and extending the piezoelectric thin films in each space room. CONSTITUTION:A diaphragm 1 made of foamed resin is discoid; through holes 2 recessed inwardly and passed through with each other are formed at the symmetric positions of the upper and lower surfaces of a center part, and the circumferential edge of a dividing plate part 3 is embedded to constitute an upward space room 4 and a downward space room 5. In those space rooms 4 and 5, piezoelectric thin films 6 and 7 curved previously are extended projecting out. Those thin films 6 and 7 are made of piezoelectric ceramics, and silver electrodes 8, 9, 10, and 11 are baked on their main surfaces. In the surface of the diaphragm 1, recess parts 16 and 17 are formed; and the hemispherical recess part 16 performs corrugation operation for adjusting the high frequency range, and the long-sized recess part 17 performs that for adjusting the intermediate range.