| 摘要 |
PROBLEM TO BE SOLVED: To provide an SAW filter device capable of hermetically sealing an electrode for an SAW filter. SOLUTION: A piezoelectric substrate 2 comprising a plurality of SAW filter electrodes 21 and 22 on its surface is jointed on a base substrate 1 by a sealing frame 3 at a specified interval. The SAW filter electrodes 21, 22 formed on the base substrate side of the piezoelectric substrate 2 are hermetically sealed by the sealing frame 3. A sealing resin layer 4 whose thermal expansion factor at -40 to 125°C is larger than the piezoelectric substrate 2 is so formed on the base substrate 1 as at least the side surface of the piezoelectric substrate 2 is covered. No sealing resin layer 4 is present on the upper surface of the piezoelectric substrate 2, otherwise, the sealing resin layer 4 is present on the upper surface of the piezoelectric substrate 2 by a thickness of 50μm or less. COPYRIGHT: (C)2007,JPO&INPIT
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