| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric resonant element which reduces spuriousness, making it possible to form a thinner piezoelectric substrate, a filter using the substrate and the piezoelectric resonator, and a composite substrate. SOLUTION: An interdigital transducer (IDT) composed of a pair of interdigital electrodes is formed in a part of a main surface of one side of a piezoelectric substrate, and an isolate conductor layer opposed to the IDT is provided. The interdigital electrodes has a plurality of electrode fingers respectively, and the electrode fingers of a pair of interdigital electrodes are arranged to be parallel to each other. It is preferable that the isolated conductor layer is larger than an area of an electrode crossing portion where the electrode fingers are mutually crossed, and is provided in the main surface of the other side of the piezoelectric substrate. COPYRIGHT: (C)2005,JPO&NCIPI
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