Piezo electric vibrator unit sealed with 90Sn-10Au solder

摘要

A vibrator unit for use in a timepiece comprises a vibrator mounted within a ceramic case. A glass lid is airtightly sealed to the ceramic case by means of a soldering washer soldered between opposing surface portions of the lid and case. The soldering washer consists essentially of 90Sn-10Au solder alloy which enables formation of the airtight seal at lower and/or shorter soldering temperatures than would be the case with conventional solder alloys thereby avoiding an increase in the equivalent impedance of the vibrator unit which would otherwise occur. As the equivalent impedance can be maintained at a low value, the vibrator unit can therefore be made smaller without adversely affecting the equivalent impedance which is maintained below 350 K OMEGA .