| 摘要 |
PURPOSE:To obtain excellent temperature characteristics of a elastic surface wave element whose surface-wave acoustic velocity can be controlled, by giving a piezoelectric substrate external uniform mechanical strain and by compensating the temperature variation of frequency characteristics by controlling the mechanical strain. CONSTITUTION:On the top surface of piezoelectric substrate 41, comb-shaped electrodes 42 and 42' are aligned in the propagation of a elastic surface wave and magnetostrictive substrate 44 provided with electromagnet 45 is bonded covering the entire reverse surface of substrate 41. Since this substrate 44 is displaced evenly by a DC bias magnetic field provided by electromagnet 45, the compensation of temperature characteristics can be made purely electrical. Namely, uniform mechanical strain, applied externally to substrate 41, is controlled to compensate the temperature variation of frequency characteristics, so that excellent temperature characteristic is obtained. |
