Title:
ELASTIC WAVE DEVICE
Document Type and Number:
WIPO Patent Application WO/2024/070893
Kind Code:
A1
Abstract:
Provided is an elastic wave device capable of more reliably suppressing the transverse mode. The elastic wave device comprises a piezoelectric layer provided on an acoustic reflection film, and an IDT provided thereon. The elastic wave device further comprises a mass-addition film which is provided in an edge region continuously so as to overlap a plurality of electrode finger portions and a region between the electrode finger portions. The elastic wave device is characterized in that, when the value obtained by dividing the product of the density and thickness of a given layer by the density of Al and a wavelength λ and expressed in percentage is an Al-equivalent normalized thickness of the layer, the total of the Al-equivalent normalized thicknesses of electrode finger portion layers is the Al-equivalent normalized thickness TIDT [%] of the electrode finger portions, the Al-equivalent normalized thickness of a mass-addition film 9 is Tm [%], the value obtained by dividing the thickness ratio of the Al-equivalent normalized thickness Tm of the mass-addition film 9 to the Al-equivalent normalized thickness TIDT of the electrode finger portions by 3.15 is TR [%], the duty ratio of an IDT 27 is d, and the value obtained by dividing the dimension along the electrode finger portion extending direction of the mass-addition film 9 by the wavelength λ is the wavelength ratio width W, TR and W are in an ellipse or a rectangle as shown in Figs. 4 to 8.
Inventors:
SHIMIZU YASUHIRO (JP)
ITO DAISUKE (JP)
ITO DAISUKE (JP)
Application Number:
PCT/JP2023/034325
Publication Date:
April 04, 2024
Filing Date:
September 21, 2023
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145; H03H9/25
Foreign References:
| JP2019068309A | 2019-04-25 | |||
| JP2020109957A | 2020-07-16 | |||
| JP2017175276A | 2017-09-28 | |||
| JP2016136712A | 2016-07-28 | |||
| US20210126616A1 | 2021-04-29 |
Attorney, Agent or Firm:
OSAKA FRONT (JP)
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