| 摘要 |
PURPOSE:To form the element with stable characteristics at low cost, by using beryllium oxide as piezoelectric material, forming the thin film of beryllium oxide on the insulated base, and making unnecessary additives through the combination with interdigital electrodes. CONSTITUTION:One surface of the base 11 like glass, the input electrode 12 and output electrode 13 with interdigital electrodes are formed, the pizeoelectric thin film 14 of beryllium oxide BeO is covered on it, and the absorbing member 15 avoiding unnecessary elastic surface waves is partly coated. Further, the piezoelectric thin film of beryllium oxide is formed to the base 11 to form the interdigital electrode on the thin film or interdigital electrode at the opposite side of the base forming the piezoelectric thin film. By using the thin film of beryllium oxide, the sound velocity of elastic surface waves is accelerated, and the wavelength to the same frequency is increased, allowing to make easy the design of the electrode pattern and to make stable the characteristics of the elastic surface wave element. |
