Title:
ELASTIC WAVE DEVICE
Document Type and Number:
WIPO Patent Application WO/2023/085347
Kind Code:
A1
Abstract:
Provided is an elastic wave device that can suppress unnecessary waves within the band between the resonance frequency and the anti-resonance frequency, and can reduce insertion loss. An elastic wave device 10 according to the present invention comprises: a support member including a support substrate; a piezoelectric layer 14 provided on the support member, made from lithium niobate or lithium tantalate, and having a first main surface 14a and a second main surface 14b facing each other; an IDT electrode 11 provided on the first main surface 14a of the piezoelectric layer 14, and having a pair of bus bars (first and second bus bars 26, 27) and a plurality of electrode fingers (plurality of first and second electrode fingers 28, 29); and at least one mass addition film provided on the piezoelectric layer 14. In a plan view viewed along the direction in which the support member and the piezoelectric layer 14 are layered, an acoustic reflector is formed at a position overlapping at least a portion of the IDT electrode 11. d/p ≤ 0.5, where d is the thickness of the piezoelectric layer 14 and p is the distance between the centers of adjacent electrode fingers. Some of the plurality of electrode fingers are connected to one of the bus bars of the IDT electrode 11. The remaining electrode fingers are connected to the other bus bar. A plurality of electrode fingers connected to one bus bar and a plurality of electrode fingers connected to the other bus bar are interdigitated. Adjacent electrode fingers overlap each other in an intersecting region F when viewed from the electrode-finger-opposing direction, which is the direction in which adjacent electrode fingers oppose each other. Regions positioned between the intersecting region F and the pair of bus bars are a pair of gap regions (first and second gap regions G1, G2). At least one mass addition film (first mass addition film 24) overlaps the gap region in plan view, and is provided on the second main surface 14b of the piezoelectric layer 14.
Inventors:
DAIMON KATSUYA (JP)
Application Number:
PCT/JP2022/041862
Publication Date:
May 19, 2023
Filing Date:
November 10, 2022
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145; H03H9/25; H03H9/64
Domestic Patent References:
| WO2021060523A1 | 2021-04-01 | |||
| WO2019139076A1 | 2019-07-18 |
Foreign References:
| JP2013518455A | 2013-05-20 |
Attorney, Agent or Firm:
OSAKA FRONT (JP)
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