Nihon Dempa Kogyo Co., Ltd.

Masaaki Nakahara

Shigeru Obara

Yuki Oi

Yuya Nishimura

Tetsuya Sato

Tomonori Shibazaki

Kazuhiro Hirota

Shigetaka Kaga

Yoshiro Teshima

Takahiko Iwasaki

Genwa Koki

A crystal resonator includes a flat plate-shaped crystal element and excitation electrodes. The crystal element has principal surfaces parallel to an X'-axis and a Z&#x2032;-axis. The X&#x2032;-axis is an axis of rotating an X-axis in a range of 15 to 25 degrees around a Z-axis. The Z&#x2032;-axis is an axis of rotating the Z-axis in a range of 33 to 35 degrees around the X&#x2032;-axis. The excitation electrodes are formed on the respective principal. The excitation electrodes include a first region with a circular outer shape and a second region. The second region is formed at a peripheral area of the first region. The second region has a thickness thinner than the first region and has an elliptical outer shape. The elliptical shape has a long axis extending in a direction in a range of &#x2212;5 to +15 degrees with respect to a direction that the X&#x2032;-axis extends.

Crystal resonator

A crystal resonator includes a crystal element and excitation electrodes. The crystal element has a pair of principal surfaces parallel to an X'-axis and a Z&#x2032;-axis. The X&#x2032;-axis is an axis of rotating an X-axis as a crystallographic axis of a crystal in a range of 15 degrees to 25 degrees around a Z-axis as a crystallographic axis of the crystal. The Z&#x2032;-axis is an axis of rotating the Z-axis in a range of 33 degrees to 35 degrees around the X&#x2032;-axis. The excitation electrodes are formed on the respective principal surfaces of the crystal element. Elliptical mesa portions or elliptical inverted mesa portions are formed on the respective principal surfaces. The mesa portions project from outer peripheries of the principal surfaces. The inverted mesa portions are depressed from the outer peripheries of the principal surfaces.

A piezoelectric vibrating piece includes a vibrating piece body including a vibrator and at least one pair of excitation electrodes formed on a front surface and a back surface of the vibrator. The vibrating piece body is a twice rotated quartz-crystal vibrating piece. The pair of excitation electrodes are arranged in a Z'&#x2033;-axis direction determined by an X&#x2032;&#x2033;-axis and obliquely disposed with respect to the Y&#x2033;-axis direction. The X&#x2032;&#x2033;-axis is rotated by 260&#xb0; to 300&#xb0; counterclockwise about a Y&#x2033;-axis using a +X&#x2033;-axis direction as a reference. The pair of excitation electrodes are formed to have respective semicircle shapes including straight line portions extending in the X&#x2032;&#x2033;-axis direction and to be disposed in a state where the straight line portions overlapping with one another. The straight line portion of the excitation electrode includes an inclined portion that gradually decreases in thickness toward an end portion of the excitation electrode.

Piezoelectric vibrating piece and piezoelectric device

The present invention relates to a crystal oscillator that is provided with a crystal element; a main surface electrode configured of a first underlayer formed on each of two main surfaces of the crystal element and a first surface layer of Au superimposed over the first underlayer; an end surface electrode having a second underlayer formed on the crystal element to extend over the main surface electrode and a second surface layer of Au superimposed to cover the second underlayer; a supporter for holding the crystal element in the horizontal direction, bonded to the end surface electrode by a eutectic alloy comprising at least Au; and a base on which the supporter stands. An intermediate layer is provided between the second underlayer and the second surface layer of the end surface electrode; the intermediate layer protrudes further towards the center over the main surface electrode than the second surface layer; and also the intermediate layer is formed of a metal having the characteristic of increasing the adhesive strength between the underlayer and the second surface layer as well as that of the eutectic alloy. The present invention provides a crystal oscillator in which bonding is done with a eutectic alloy that has a higher bond strength, thus preventing peeling of the electrodes.

Growing community of inventors

Saitama, Japan

Masaaki Nakahara