| 摘要 |
PURPOSE:To achieve easy manufacture by avoiding a crossing part, through the provision of electrodes so that a piezoelectric film provided on a substrate can be clipped. CONSTITUTION:A metallic electrode C is provided on a substrate 1 of a piezoelectric substance such as lithium niobate or nonpiezoelectric substance such as glass. A piezoelectric film 2 is laminated further on it. Metallic electrodes A and B are provided on the film 2. Phase difference of 120 degrees is given among the electrodes A,B, and C. The electrode fingers of the electrodes A, B and C are alternately arranged in the interval of a wavelength lambda. As a result, unidirectional surface acoustic waves only are obtained, because the waves from each electrode are synthesized to be strengthened for one surface acoustic wave and the waves from each electrode are cancelled for another surface wave. |
