| 摘要 |
PROBLEM TO BE SOLVED: To provide a laminated piezoelectric filter whose shape and characteristic are not changed by temperature changes. SOLUTION: An outer case composed of a top printed circuit board, a bottom printed circuit board, etc., is never deformed by the influence of the heat at reflow soldering, etc., by using a hollow pipe-shaped emission member for a frame-shaped insulation spacer. Epoxy resin using hollow pipe-shaped glass fiber as a base material is used as the emission member to form a frame-shaped insulation spacer, and in addition to the above effect, there is thereby little possibility that foreign matters are mixed because the top printed circuit board does not have holes. Namely, it is possible to easily obtain a laminated piezoelectric filter that has little possibility of characteristic deterioration, short-circuiting, etc.
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