Piezoelectric vibrator for reduction of undesired vibrations

A piezo-resonator utilizing thickness shear vibration, comprising:

• a piezoelectric substrate having an elongated rectangular shape with a first major surface and a second major surface thereof;
• first and second excitation electrodes formed on said first major surface of said piezoelectric substrate, said first and second excitation electrodes being formed on said first major surface at portions of said piezoelectric substrate that are closer to a first longitudinal end portion of said piezoelectric substrate than a predetermined portion of said piezoelectric substrate along the longitudinal direction thereof;
• a first lead line being connected to said first excitation electrode and extending toward a second longitudinal end portion of said piezoelectric substrate while passing through said predetermined portion thereof;
• a second lead line being connected to said second excitation electrode and extending toward said first longitudinal end portion of said piezoelectric substrate;
• an earth electrode being formed on said second major surface of said piezoelectric substrate so as to be simultaneously opposed to both of said first and second excitation electrodes through said piezoelectric substrate;
• an earth terminal electrode formed on said second major surface at said predetermined portion of said piezoelectric substrate and connected to said earth electrode through an earth lead line,
• said earth terminal electrode being spaced away from a portion of said second major surface directly opposite said first lead line so as to prevent said earth terminal electrode from being opposed to said first lead line through said piezoelectric substrate;
• and
• an electrically insulating film formed on said second major surface at said portion from which said earth terminal electrode is spaced away.