| 摘要 |
PURPOSE:To decrease the value of a crystal impedance (CI) of an oscillator operated in the thickness bending oscillation mode, by providing metallic thin film electrodes having electric polarity and a metallic thin film electrode not connected to any electric polarity. CONSTITUTION:The metallic thin film electrodes having different electric polarity are taken as the 1st and the 2nd electrodes and the polarity of an electric terminal 40 is ositive and that of an electric terminal is negative. Further, the other electrode 19 (3rd electrode) not connected to any of the 1st and 2nd electrodes is provided. The distriution of electric line of force of the 1st and the 2nd electrodes is changed by providing the 3rd electrodes 19. That is, the electric line of force 50 from the 1st electrode enters one end of the 3rd electrode 19 once and starts from the other end of the 3rd electrode 19 and enters again the 2nd electrode. As a result, the distribution of the electric line of force 50 is much in the vicinity of the surface of the oscillator 1, an effective electric field component Ex is increased and an ineffective electric field component Ez is decreased. Thus, the CI value of the oscillator 1 is smaller when the 3rd electrode is provided than in the case otherwise. |
