Thickness extension vibration mode piezoresonator, trapezoidal filter and piezoresonator component

Application Number: 00126484
Application Date: 2000.08.28
Publication Number: 1286528
Publication Date: 2001.03.07
Priority Information: 1999/8/26 JP 240113/99
International: H03H9/17;H03H9/54
Applicant(s) Name: Murata Mfg. Co., Ltd.
Inventor(s) Name: Nishimura Toshio
Patent Agency Code: 31100
Patent Agent: shen zhaokun
Abstract A thickness extensional vibration mode piezoelectric resonator includes a piezoelectric body having piezoelectric layers and N internal electrodes disposed therein, where N is an integer equal to 3 to 5. Electric fields of opposite polarity are applied alternately in the direction of thickness to the piezoelectric layers located between the internal electrodes. When the thickness of a piezoelectric layer between adjacent internal electrodes in the direction of thickness is denoted by D and the thicknesses of a first and second piezoelectric layer outside the outermost internal electrodes in the direction of thickness are denoted by D1 and D2, the following relationships are satisfied: 0.50<=(D1+D2)/2D<=1.00 at N=3, 0.50<=(D1+D2)/2D<=0.90 at N=4, and 0.50<=(D1+D2)/2D<=0.80 at N=5.