Title:
ELASTIC WAVE DEVICE
Document Type and Number:
WIPO Patent Application WO/2023/190654
Kind Code:
A1
Abstract:
Provided is an elastic wave device wherein unnecessary waves can be suppressed. An elastic wave device 10 according to the present invention comprises: a support member that includes a support board; a piezoelectric layer 14 that is provided on the support member; an IDT electrode 11 that has a pair of mutually opposed bus bars (first and second bus bars 26, 27) provided on the piezoelectric layer 14 and that also has a plurality of electrode fingers (a plurality of first and second electrode fingers 28, 29); and a plurality of mass-adding films 17 that are provided on the plurality of electrode fingers. An acoustic reflection part is provided at a position that overlies at least a portion of the IDT electrode 11 on the support member in a plan view seen along the direction of stacking the support member and the piezoelectric layer 14. When the thickness of the piezoelectric layer 14 is d and the center distance between the adjacent electrode fingers is p, d/p is equal to or less than 0.5. The plurality of electrode fingers each have a proximal end connected to the bus bar and also have a distal end opposed to the proximal end. An interlace range F is a range where the adjacent electrode fingers are stacked one over another when viewed in the orthogonal-to-electrode-finger direction that is orthogonal to the electrode-finger-extending direction in which the plurality of electrode fingers extend. The interlace range F includes: a central region H; and a first edge region Ea and a second edge region Eb that sandwich the central region H in the electrode-finger-extending direction and that are opposed to each other. At least some of the plurality of mass-adding films 17 each overlie the central region H in the plan view. The mass-adding films 17 on the electrode fingers are either mass-adding films 17 provided continuously from the proximal end side to the distal end side or mass-adding films 17 provided intermittently from the proximal end side to the distal end side. A mass-adding-film forming part 18 is constituted only by the plurality of mass-adding films 17. The thickness of at least a portion of the mass-adding-film forming part 18 varies in at least one of the orthogonal-to-electrode-finger direction and the electrode-finger-extending direction.
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Inventors:
DAIMON KATSUYA (JP)
Application Number:
PCT/JP2023/012752
Publication Date:
October 05, 2023
Filing Date:
March 29, 2023
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145
Domestic Patent References:
| WO2021060523A1 | 2021-04-01 | |||
| WO2021246447A1 | 2021-12-09 | |||
| WO2021153734A1 | 2021-08-05 | |||
| WO2018131360A1 | 2018-07-19 | |||
| WO2020171050A1 | 2020-08-27 | |||
| WO2017131170A1 | 2017-08-03 | |||
| WO2021060521A1 | 2021-04-01 |
Foreign References:
| JPH09331226A | 1997-12-22 | |||
| JP2021150893A | 2021-09-27 |
Attorney, Agent or Firm:
OSAKA FRONT (JP)
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