| US 7,525,399 B2 | ||
| Thin-film piezoelectric resonator, filter and voltage-controlled oscillator | ||
| Naoko Yanase, Kawasaki (Japan); Kenya Sano, Kawasaki (Japan); Takaaki Yasumoto, Kawasaki (Japan); Ryoichi Ohara, Kawasaki (Japan); and Kazuhiko Itaya, Yokohama (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Mar. 16, 2006, as Appl. No. 11/376,266. | ||
| Claims priority of application No. 2005-160242 (JP), filed on May 31, 2005. | ||
| Prior Publication US 2006/0267711 A1, Nov. 30, 2006 | ||
| Int. Cl. H03H 9/54 (2006.01); H03H 9/15 (2006.01) | ||
| U.S. Cl. 333—189 [333/187; 310/324; 310/335] | 11 Claims |
| 1. A thin-film piezoelectric filter comprising:
a substrate including a first cavity and a second cavity disposed separately from each other;
a first excitation portion disposed over the first cavity, the first excitation portion including a first electrode, a first
piezoelectric material and a second electrode laminated successively, an overlapping region among the first electrode, the
first piezoelectric material and the second electrode defining a contour of a periphery of the first excitation portion, a
first distance defined as a distance from an end of the first excitation portion to an opening end of the first cavity; and
a second excitation portion disposed over the second cavity, the second excitation portion including a third electrode, a
second piezoelectric material and a fourth electrode laminated successively, an overlapping region among the third electrode,
the second piezoelectric material and the fourth electrode defining a contour of a periphery of the second excitation portion,
a second distance defined as a distance from an end of the second excitation portion to an opening end of the second cavity,
the second distance being different from the first distance, the second distance, less an alignment tolerance, is longer than
the first distance.
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