Title:
ELASTIC WAVE DEVICE AND FILTER DEVICE
Document Type and Number:
WIPO Patent Application WO/2023/140354
Kind Code:
A1
Abstract:
Provided is an elastic wave device that can inhibit unnecessary waves near the resonant frequency or near the anti-resonant frequency, even in a configuration in which a mass-addition film is provided to an edge region. This elastic wave device 10 comprises: a support member including a support substrate; a piezoelectric layer 14 that is provided on the support member and is made of lithium tantalate or lithium niobate; and an IDT electrode 11 that is provided on the piezoelectric layer 14 and has a pair of busbars (first and second busbars 26, 27), and a plurality of electrode fingers (plurality of first and second electrode fingers 28, 29). In a plan view seen along the lamination direction of the support member and the piezoelectric layer 14, an acoustic reflection part is provided at a position, on the support member, overlapping with at least a portion of the IDT electrode 11. When the thickness of the piezoelectric layer 14 is defined as d, and the center-to-center distance between adjacent electrode fingers is defined as p, d/p is 0.5 or lower. Some electrode fingers among the plurality of electrode fingers are connected to one busbar among the pair of busbars. The remaining electrode fingers among the plurality of electrode fingers are connected to the other busbar. Said some electrode fingers connected to the one busbar and the remaining electrode fingers connected to the other busbar are interposed between each other. When the direction in which the plurality of electrode fingers extend is defined as the electrode finger extension direction, and the direction orthogonal to the electrode finger extension direction is defined as the electrode finger opposing direction, a region where adjacent electrode fingers are superimposed on each other when viewed from the electrode finger opposing direction is an intersecting region F. A region positioned between the intersecting region F and the pair of busbars is a pair of gap regions (first and second gap regions Ga, Gb). The intersecting region F has a central region H, and a pair of edge regions (first and second edge regions Ea, Eb) disposed so as to sandwich the central region H in the electrode finger extension direction. The elastic wave device 10 further comprises a plurality of mass-addition films (first and second mass-addition films 24, 25) that are provided across at least one edge region among the pair of edge regions and the gap region adjacent to said edge region, and that are arranged side by side along the electrode finger opposing direction. The plurality of mass-addition films are provided so as not to be positioned on at least a portion between adjacent electrode fingers.
More Like This:
| JPH07212177 | SURFACE WAVE FILTER |
| JP2000031778 | LADDER TYPE SAW FILTER |
| JP2011166567 | SURFACE ACOUSTIC WAVE DEVICE, OSCILLATOR, AND MODULE APPARATUS |
Inventors:
DAIMON KATSUYA (JP)
Application Number:
PCT/JP2023/001709
Publication Date:
July 27, 2023
Filing Date:
January 20, 2023
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145
Domestic Patent References:
| WO2020171050A1 | 2020-08-27 | |||
| WO2021013568A1 | 2021-01-28 | |||
| WO2021060513A1 | 2021-04-01 | |||
| WO2023002790A1 | 2023-01-26 |
Foreign References:
| JP2020109957A | 2020-07-16 | |||
| JP2016178387A | 2016-10-06 |
Attorney, Agent or Firm:
OSAKA FRONT (JP)
Download PDF:
Previous Patent: GATE DRIVE CIRCUIT, SWITCHING CIRCUIT, SWITCHING POWER SUPPLY, AND CONTROL CIRCUIT FOR SAME
Next Patent: CANCER TREATMENT DRUG
Next Patent: CANCER TREATMENT DRUG