Title:
ELASTIC WAVE DEVICE AND ELASTIC WAVE ELEMENT
Document Type and Number:
WIPO Patent Application WO/2024/085062
Kind Code:
A1
Abstract:
Provided is an elastic wave device that can suppress an increase in return loss. An elastic wave device 1 comprises: a piezoelectric substrate 2; an IDT electrode 3 that includes a first bus bar 4 and a second bus bar 5 that are provided on the piezoelectric substrate 2 and are opposed to each other, and a plurality of first electrode fingers 6 and a plurality of second electrode fingers 7 that are interdigitated with each other; and a pair of reflectors 13A, 13B that are provided on the piezoelectric substrate 2 so as to oppose each other across the IDT electrode 3 in a second direction x orthogonal to a first direction y in which the plurality of first electrode fingers 6 and the plurality of second electrode fingers 7 extend. Each of the plurality of first electrode fingers 6 includes a first proximal end 6a connected to the first bus bar 4. Each of the plurality of second electrode fingers 7 includes a second proximal end 7a connected to the second bus bar 5. A pair of the regions of the IDT electrode 3 that are positioned outside in the first direction y of the first proximal end 6a and the second proximal end 7a are a pair of outer regions (first and second outer regions Ba, Bb). Extensions of the pair of outer regions in the second direction x are a pair of extension outer regions (first and second extension outer regions Oa, Ob). The reflectors each include a pair of reflector bus bars (first and second reflector bus bars 14, 15) opposing each other, and a plurality of reflector electrode fingers 16 electrically connected to the pair of reflector bus bars. The reflector bus bars are provided in portions of the reflectors positioned in the extension outer regions, and include a plurality of reflector-connecting electrodes 15c that are connected to the plurality of reflector electrode fingers 16 directly or indirectly. The regions of the reflectors in which the plurality of reflector-connecting electrodes 15c are positioned and that extend in the second direction x are connection electrode-forming regions C. When twice the center-to-center distance in the second direction x between adjacent reflector electrode fingers 16 is a one-period dimension, and the percentage of the dimension of a portion, over a virtual line E of the one-period dimension extending in the second direction x, in which the piezoelectric substrate 2 is covered by the metal of which the reflectors are composed is a metallization ratio, the connection electrode-forming region C of at least one reflector bus bar of at least one of the reflectors includes a portion having different metallization ratios in at least one of the first direction y and the second direction x.
Inventors:
TAKIGAWA KAZUHIRO (JP)
Application Number:
PCT/JP2023/037030
Publication Date:
April 25, 2024
Filing Date:
October 12, 2023
Export Citation:
Assignee:
MURATA MFG CO LTD (JP)
International Classes:
H03H9/145
Attorney, Agent or Firm:
OSAKA FRONT (JP)
Download PDF:
Previous Patent: SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD
Next Patent: FLUID PRESSURE CYLINDER
Next Patent: FLUID PRESSURE CYLINDER