Resonator and piezoelectric resonance device with grooved lead terminals thereof

A resonator comprising:

• a piezoelectric element;
• a lead terminal comprised of an electro-conductive wire material for holding an end of the piezoelectric element, formed by press working with a tapered V-shaped or trapezoidal receiving groove for holding an end of the piezoelectric element, the cross-sectional shape of the wire material constituting the lead terminal being substantially circular at the portion not formed with the tapered V-shaped or trapezoidal receiving groove and the tapered V-shaped or trapezoidal receiving groove having an open portion, with a cross section wider than the thickness of the end of the piezoelectric element, and a pair of inclined straight line side walls extending from a top of the groove to a bottom of the groove;
• and
• a capacitor connected to the top end of the lead terminal in a state with the end of the piezoelectric element held by the lead terminal so as to constitute a resonance circuit together with the piezoelectric element, wherein
• a difference of a coefficient of heat expansion of a piezoelectric ceramic constituting the piezoelectric element and a coefficient of heat expansion of a dielectric ceramic constituting the capacitor is not more than 5 ppm/° C.

A piezoelectric resonance device comprising:

• a tapered V-shaped or trapezoidal receiving groove having an open portion and a pair of inclined straight line side walls extending from a top of the groove to a bottom of the groove;
• a piezoelectric element having ends located within the receiving groove, the groove having a cross section wider than the thickness of the end of the piezoelectric element;
• and
• a sealing resin portion for covering the piezoelectric element so that a vibrating space is formed around a vibrating section of the piezoelectric element, wherein
• the area of the surface of the piezoelectric element within the vibrating space is in a predetermined relation with the frequency band of the piezoelectric element.