IP Library › Patent Application 18099986
Patent Application
App. No. 18/099,986

ACOUSTIC WAVE DEVICE

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Quick Facts
Patent No.
US None
App. No.
18/099,986
Abstract

An acoustic wave device includes an IDT electrode with an inclined IDT structure on a piezoelectric substrate. An intersection region, where a first electrode finger and a second electrode finger overlap each other when viewed in an acoustic wave propagation direction, includes a central region and first and second low acoustic velocity regions on both sides of the central region. The first and second low acoustic velocity regions have an asymmetric shape about a central axis extending in a length direction of the first and second electrode fingers.

Claims (72)

1 . An acoustic wave device, comprising:

a piezoelectric substrate; and

an IDT electrode on the piezoelectric substrate; wherein

the IDT electrode includes:

a first busbar;

a second busbar separated from the first busbar;

a plurality of first electrode fingers including one end connected to the first busbar, a plurality of second electrode fingers including one end connected to the second busbar;

a plurality of first dummy electrodes connected to the second busbar, tip ends of the first dummy electrodes facing tip ends of the first electrode fingers with a second gap interposed therebetween; and

a plurality of second dummy electrodes connected to the first busbar, tip ends of the second dummy electrodes facing tip ends of the second electrode fingers with a first gap interposed therebetween; and

when a first virtual line connecting the tip ends of the plurality of second electrode fingers is inclined with respect to an acoustic wave propagation direction that is a direction orthogonal to a direction in which the first and second electrode fingers extend, a distance between a tip end of a second electrode finger on one side, of a pair of second electrode fingers included in the second electrode fingers adjacent to any first electrode finger included in the first electrode fingers, and a base end of the first electrode finger is shorter than a distance between a tip end of the second electrode finger on an other side of the pair and the base end of the first electrode finger, and a direction toward a direction in which the distance is longer in the first virtual line is an inclination direction;

the acoustic wave device further comprises at least one of:

a projecting portion protruding toward the first electrode finger or the second electrode finger, in at least one of a side in the inclination direction at a tip end of the second electrode finger, a side opposite to the inclination direction at a tip end of a second dummy electrode included in the second dummy electrodes, a side opposite to the inclination direction of the first electrode finger positioned on an extension in the inclination direction from the tip end of the second dummy electrode, and a side in the inclination direction of the first electrode finger positioned on an extension in the inclination direction from the tip end of the second electrode finger; and

a recessed portion provided in at least one of a side opposite to the inclination direction at the tip end of the second electrode finger, a side in the inclination direction at the tip end of the second dummy electrode, a side in the inclination direction of the first electrode finger positioned on the extension in the inclination direction from the tip end of the second dummy electrode, and a side opposite to the inclination direction of the first electrode finger positioned on the extension in the inclination direction from the tip end of the second electrode finger.

2 . The acoustic wave device according to claim 1 , wherein

a third virtual line connecting the tip ends of the plurality of first electrode fingers is inclined with respect to the acoustic wave propagation direction, a distance between a tip end of a first electrode finger on one side, of a pair of first electrode fingers included in the first electrode fingers adjacent to any second electrode finger included in the second electrode fingers, and a base end of the second electrode finger is shorter than a distance between a tip end of the first electrode finger on an other side of the pair and the base end of the second electrode finger, a side closer to the first electrode finger for which the distance is shorter, of sides of the second electrode finger, and a side closer to the first electrode finger for which the distance is shorter, of sides of the second dummy electrode facing the second electrode finger, are each a first side, and a side opposite to the first side is a second side;

a distance between a tip end of a second electrode finger on one side, of a pair of second electrode fingers included in the second electrode fingers adjacent to any first electrode finger included in the first electrode fingers, and a base end of the first electrode finger is shorter than a distance between a tip end of the second electrode finger on an other side of the pair and the base end of the first electrode finger, a side closer to the second electrode finger for which the distance is shorter, of sides of the first electrode finger, and a side closer to the second electrode finger for which the distance is shorter, of sides of a first dummy electrode included in the first dummy electrodes facing the first electrode finger, are each a second side, and a side opposite to the second side is a first side;

a line connecting respective centers of second gaps, each of which is the second gap interposed between the tip ends, is a fourth virtual line; and

the acoustic wave device further comprises at least one of:

a recessed portion provided in at least one of a side in the inclination direction at a tip end of the first electrode finger, a side opposite to the inclination direction at a tip end of the first dummy electrode, a side opposite to the inclination direction of the second electrode finger positioned on an extension opposite to the inclination direction from the tip end of the first dummy electrode, and a side in the inclination direction of the second electrode finger positioned on an extension opposite to the inclination direction from the tip end of the first electrode finger; and

a projecting portion protruding toward the first electrode finger or the second electrode finger, in at least one of a side opposite to the inclination direction at the tip end of the first electrode finger, a side in the inclination direction at the tip end of the first dummy electrode, a side in the inclination direction of the second electrode finger positioned on the extension opposite to the inclination direction from the tip end of the first dummy electrode, and a side opposite to the inclination direction of the second electrode finger positioned on the extension opposite to the inclination direction from the tip end of the first electrode finger.

3 . The acoustic wave device according to claim 1 , wherein the piezoelectric substrate includes a piezoelectric film, and a high acoustic velocity material layer made of a high acoustic velocity material by which an acoustic velocity of a bulk wave propagating through the high acoustic velocity material layer is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric film.

4 . The acoustic wave device according to claim 3 , further comprising a low acoustic velocity material layer laminated between the high acoustic velocity material layer and the piezoelectric film, and made of a low acoustic velocity material by which an acoustic velocity of a bulk wave propagating through the low acoustic velocity material layer is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric film.

5 . The acoustic wave device according to claim 3 , wherein the high acoustic velocity material layer is a high acoustic velocity support substrate made of the high acoustic velocity material.

6 . The acoustic wave device according to claim 1 , wherein the piezoelectric substrate is a piezoelectric substrate made of a piezoelectric single crystal.

7 . The acoustic wave device according to claim 6 , wherein the piezoelectric single crystal is a LiTaO 3 .

8 . An acoustic wave device, comprising:

a piezoelectric substrate; and

an IDT electrode on the piezoelectric substrate; wherein

the IDT electrode includes:

a first busbar;

a second busbar separated from the first busbar;

a plurality of first electrode fingers including one end connected to the first busbar, a plurality of second electrode fingers including one end connected to the second busbar;

a plurality of first dummy electrodes connected to the second busbar, tip ends of the first dummy electrodes facing tip ends of the first electrode fingers with a second gap interposed therebetween; and

a plurality of second dummy electrodes connected to the first busbar, tip ends of the second dummy electrodes facing tip ends of the second electrode fingers with a first gap interposed therebetween;

a first virtual line connecting the tip ends of the plurality of second electrode fingers is inclined with respect to an acoustic wave propagation direction that is a direction orthogonal to a direction in which the first and second electrode fingers extend;

a distance between a tip end of a second electrode finger on one side, of a pair of second electrode fingers included in the second electrode fingers adjacent to any first electrode finger included in the first electrode fingers, and a base end of the first electrode finger is shorter than a distance between a tip end of the second electrode finger on an other side of the pair and the base end of the first electrode finger, a side closer to the second electrode finger for which the distance is shorter, of sides of the first electrode finger, and a side closer to the second electrode finger for which the distance is shorter, of sides of a first dummy electrode included in the first dummy electrodes facing the first electrode finger, are each a first side, and a side opposite to the first side is a second side;

a distance between a tip end of a first electrode finger on one side, of a pair of first electrode fingers included in the first electrode fingers adjacent to any second electrode finger included in the second electrode fingers, and a base end of the second electrode finger is shorter than a distance between a tip end of the first electrode finger on an other side of the pair and the base end of the second electrode finger, a side closer to the first electrode finger for which the distance is shorter, of sides of the second electrode finger, and a side closer to the first electrode finger for which the distance is shorter, of sides of a second dummy electrode included in the second dummy electrodes facing the second electrode finger, are each a second side, and a side opposite to the second side is a first side;

a line connecting respective centers of first gaps, each of which being the first gap interposed between the tip ends, is a second virtual line;

of a portion closer to the first gap of the second dummy electrode, a region closer to the first side is a first region and a region closer to the second side is a second region, of a portion closer to the first gap of the second electrode finger, a region closer to the first side is a fifth region and a region closer to the second side is a sixth region, and in the first electrode finger that is adjacent, in a portion closer to the first busbar with respect to the second virtual line, a region closer to the first side is a third region and a region closer to the second side is a fourth region, and in the first electrode finger, in a portion closer to the second busbar with respect to the second virtual line, a region closer to the first side is a seventh region and a region closer to the second side is an eighth region;

in the first region, the third region, the sixth region, and the eighth region, an angle defined by the first side or the second side in each region, and the first virtual line is an acute angle, and in the second region, the fourth region, the fifth region, and the seventh region, an angle defined by the first side or the second side positioned in each region, and the first virtual line is an obtuse angle; and

at least one of a projecting portion in at least one region of the first region, the third region, the sixth region, and the eighth region, and a recessed portion in at least one region of the second region, the fourth region, the fifth region, and the seventh region is provided.

9 . The acoustic wave device according to claim 8 , wherein

an intersection region that is a region in which the first electrode finger and the second electrode finger overlap when viewed in the acoustic wave propagation direction includes a central region positioned at a center in the direction in which the first and second electrode fingers extend, and first and second low acoustic velocity regions provided on both outer side portions of the central region; and

the recessed portion or the projecting portion is provided in the first and second low acoustic velocity regions.

10 . The acoustic wave device according to claim 8 , further comprising:

the projecting portion provided in at least one region of the first region, the third region, the sixth region, and the eighth region; and

the recessed portion provided in at least one region of the second region, the fourth region, the fifth region, and the seventh region.

11 . The acoustic wave device according to claim 10 , further comprising:

the recessed portion provided in the second region and the fifth region; and

the projecting portion provided in the first region and the sixth region.

12 . The acoustic wave device according to claim 11 , wherein in at least one of a portion in which the second region and the third region face each other in the acoustic wave propagation direction and a portion in which the sixth region and the seventh region face each other in the acoustic wave propagation direction, the recessed portion is provided in the second region and the seventh region, and the projecting portion is provided in the third region and the sixth region.

13 . The acoustic wave device according to claim 8 , wherein

a third virtual line connecting the tip ends of the plurality of first electrode fingers is inclined with respect to the acoustic wave propagation direction, a distance between a tip end of a first electrode finger on one side, of a pair of first electrode fingers included in the first electrode fingers adjacent to any second electrode finger included in the second electrode fingers, and a base end of the second electrode finger is shorter than a distance between a tip end of the first electrode finger on an other side of the pair and the base end of the second electrode finger, a side closer to the first electrode finger for which the distance is shorter, of sides of the second electrode finger, and a side closer to the first electrode finger for which the distance is shorter, of sides of the second dummy electrode facing the second electrode finger, are each a first side, and a side opposite to the first side is a second side;

a distance between a tip end of a second electrode finger on one side, of a pair of second electrode fingers included in the second electrode fingers adjacent to any first electrode finger included in the first electrode fingers, and a base end of the first electrode finger is shorter than a distance between a tip end of the second electrode finger on an other side of the pair and the base end of the first electrode finger, a side closer to the second electrode finger for which the distance is shorter, of sides of the first electrode finger, and a side closer to the second electrode finger for which the distance is shorter, of sides of a first dummy electrode included in the first dummy electrodes facing the first electrode finger, are each a second side, and a side opposite to the second side is a first side;

a line connecting respective centers of second gaps, each of which is the second gap interposed between the tip ends, is a fourth virtual line; and

of a portion closer to the second gap of the first dummy electrode, a region closer to the second side is a first region and a region closer to the first side is a second region, of a portion closer to the second gap of the first electrode finger, a region closer to the second side is a fifth region and a region closer to the first side is a sixth region, and in the second electrode finger that is adjacent, in a portion closer to the second busbar with respect to the fourth virtual line, a region closer to the second side is a third region and a region closer to the first side is a fourth region, and in the second electrode finger, in a portion closer to the first busbar with respect to the fourth virtual line, a region closer to the second side is a seventh region and a region closer to the first side is an eighth region;

in the first region, the third region, the sixth region, and the eighth region, an angle defined by the first side or the second side in each region, and the third virtual line is an acute angle, and in the second region, the fourth region, the fifth region, and the seventh region, an angle defined by the first side or the second side positioned in each region, and the third virtual line is an obtuse angle; and

the acoustic wave device further comprises at least one of:

the projecting portion in at least one region of the first region, the third region, the sixth region, and the eighth region; and

the recessed portion in at least one region of the second region, the fourth region, the fifth region, and the seventh region.

14 . The acoustic wave device according to claim 8 , wherein

a third virtual line connecting the tip ends of the plurality of first electrode fingers is inclined with respect to the acoustic wave propagation direction, a distance between a tip end of a first electrode finger on one side, of a pair of first electrode fingers included in the first electrode fingers adjacent to any second electrode finger included in the second electrode fingers, and a base end of the second electrode finger is shorter than a distance between a tip end of the first electrode finger on an other side of the pair and the base end of the second electrode finger, a side closer to the first electrode finger for which the distance is shorter, of sides of the second electrode finger, and a side closer to the first electrode finger for which the distance is shorter, of sides of the second dummy electrode facing the second electrode finger, are each a first side, and a side opposite to the first side is a second side;

a distance between a tip end of a second electrode finger on one side, of a pair of second electrode fingers included in the second electrode fingers adjacent to any first electrode finger included in the first electrode fingers, and a base end of the first electrode finger is shorter than a distance between a tip end of the second electrode finger on an other side of the pair and the base end of the first electrode finger, a side closer to the second electrode finger for which the distance is shorter, of sides of the first electrode finger, and a side closer to the second electrode finger for which the distance is shorter, of sides of a first dummy electrode included in the first dummy electrodes facing the first electrode finger, are each a second side, and a side opposite to the second side is a first side;

a line connecting respective centers of second gaps, each of which is the second gap interposed between the tip ends, is a fourth virtual line; and

the acoustic wave device further comprises at least one of:

a recessed portion provided in at least one of a side in the inclination direction at a tip end of the first electrode finger, a side opposite to the inclination direction at a tip end of the first dummy electrode, a side opposite to the inclination direction of the second electrode finger positioned on an extension opposite to the inclination direction from the tip end of the first dummy electrode, and a side in the inclination direction of the second electrode finger positioned on an extension opposite to the inclination direction from the tip end of the first electrode finger; and

a projecting portion protruding toward the first electrode finger or the second electrode finger, in at least one of a side opposite to the inclination direction at the tip end of the first electrode finger, a side in the inclination direction at the tip end of the first dummy electrode, a side in the inclination direction of the second electrode finger positioned on the extension opposite to the inclination direction from the tip end of the first dummy electrode, and a side opposite to the inclination direction of the second electrode finger positioned on the extension opposite to the inclination direction from the tip end of the first electrode finger.

15 . The acoustic wave device according to claim 8 , wherein the piezoelectric substrate includes a piezoelectric film, and a high acoustic velocity material layer made of a high acoustic velocity material by which an acoustic velocity of a bulk wave propagating through the high acoustic velocity material layer is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric film.

16 . The acoustic wave device according to claim 15 , further comprising a low acoustic velocity material layer laminated between the high acoustic velocity material layer and the piezoelectric film, and made of a low acoustic velocity material by which an acoustic velocity of a bulk wave propagating through the low acoustic velocity material layer is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric film.

17 . The acoustic wave device according to claim 15 , wherein the high acoustic velocity material layer is a high acoustic velocity support substrate made of the high acoustic velocity material.

18 . The acoustic wave device according to claim 8 , wherein the piezoelectric substrate is a piezoelectric substrate made of a piezoelectric single crystal.

19 . The acoustic wave device according to claim 18 , wherein the piezoelectric single crystal is a LiTaO 3 .

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 24, 2023
From: VILENSKI, OFER; SHRIBMAN, DERRY
To: LUMINATI NETWORKS LTD.
Reel/Frame 062468/0440 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 23, 2023
From: YAMANE, TAKASHI
To: MURATA MANUFACTURING CO., LTD.
Reel/Frame 062447/0241 →