Title:
ELASTIC WAVE DEVICE
Document Type and Number:
WIPO Patent Application WO/2019/049893
Kind Code:
A1
Abstract:
The present invention provides an elastic wave device which makes it possible to suppress transverse mode ripples by certainly decreasing sound speed in edge regions when a Love wave is used. An elastic wave device 1 is provided with a piezoelectric substrate 2 having an elliptical slowness surface, an IDT electrode 3 provided on the piezoelectric substrate 2, and a dielectric film 13 provided on the piezoelectric substrate 2 so as to cover the IDT electrode 3, and uses a Love wave. The IDT electrode 3 has a cross region B where first and second electrode fingers 6, 7 overlap each other. The cross region B has a central region M and first and second edge regions X1, X2 on both sides of the central region M. When the wavelength-normalized film thickness of the IDT electrode 3 is denoted by x (%), and the electrode density of the IDT electrode 3 is denoted by y (g/cm3), the wavelength-normalized film thickness x is x or more satisfying expression (1): y = 0.0757x2-3.9023x+27.986. The thickness of the dielectric film 13 in the first and second edge regions X1, X2 is thinner than the thickness of the dielectric film 13 in the central region M.
Inventors:
DAIMON KATSUYA (JP)
Application Number:
PCT/JP2018/032884
Publication Date:
March 14, 2019
Filing Date:
September 05, 2018
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145; H03H9/25
Foreign References:
| JP2014131351A | 2014-07-10 | |||
| JP2016136712A | 2016-07-28 | |||
| JP2017112603A | 2017-06-22 |
Attorney, Agent or Firm:
MIYAZAKI & METSUGI (JP)
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