| 摘要 |
PURPOSE:To perform the shield treatment without increment of outside dimensions, by providing a shield coating layer in an armor resin layer. CONSTITUTION:External lead-out terminals 7 are fitted to a piezoelectric ceramic substrate 4 where electrodes are formed on both main faces, and the part except external lead-out terminals 7 is coated with a thermosetting resin 5 such as an epoxy resin, thereby producing a frequency band-pass filter using the energy shutting double mode. After input and output terminals 7 other than an earth terminal 2 of this filter are masked with a rubber tube, a tape, or the like, a shield film 6 is formed on the resin 5 by the vacuum vapor-deposition method or the like. An armor is provided on the shield film 6 again by the resin 5 or the like to complete the filter. Thus, the shield film 6 is connected to the earth terminal 2 to prevent the electric interference with other parts and aerial propagation of signals. |
