| 摘要 |
PURPOSE:To obtain high accuracy, by providing a crystal oscillator which can be arranged under the atmospheric pressure and a means which counts the signal related to the oscillating signal of said oscillator during the reference time interval. CONSTITUTION:A stem 1, a tuning fork type crystal oscillator chip 2, leads, 3 and 4, a protecting metal cap 5, and an opening part 6 for the protecting metal cap are provided. Owing to said opening part 6, the crystal oscillator chip 2 is placed under the external atmospheric pressure (a tuning fork type crystal oscillator used in an electronic watch is hermetically sealed). Instead of the protecting metal cap 5, a cap 7 formed by a porous material can be used. Said cap 7 can passes the atmospheric pressure but prevents the foreign matter from entering the inside. |
