Seiko Instruments Inc

Shuji Yamane

Kazuyoshi Sugama

Masashi Numata

Susumu Yoshida

Keiichi Oouchi

A piezoelectric oscillator is provided, which has a through electrode providing reliable conduction between a piezoelectric vibrating piece and an external electrode with rare occurrence of a large stress caused by temperature variation in processing or deformation of a mounted base substrate, while the hermeticity of a cavity is maintained. A piezoelectric oscillator having a piezoelectric vibrating piece sealed in a cavity defined between a base substrate and a lid substrate includes a through electrode disposed in a through hole penetrating through the base substrate, and the through electrode has a glass frit filled in the through hole and fired and a core formed of a material containing only iron and nickel and disposed in the through hole together with the glass frit. The values of the thermal expansion coefficients of the base substrate, the glass frit, and the core are set as: base substrate glass&#x2267;frit&#x3e;core.

Piezoelectric vibrator

A piezoelectric vibrator has a vibrator piece and a frame integral with the vibrator piece. The frame is connected to one end of and surrounds the vibrator piece. A lid has a surface anodically bonded to a first surface of the frame. The lid has a recessed portion at a position disposed opposite to and confronting the vibrator piece. A base has a surface anodically bonded to a second surface of the frame opposite the first surface thereof. The base has a recessed portion at a position disposed opposite to and confronting the vibrator piece. A beveled portion is formed around a surface of one of the lid and the base which does not correspond to the anodically bonded surface thereof.

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Chiba, Japan

Shuji Yamane