Elastic wave device

Abstract

Provided is an elastic wave device capable of suppressing useless waves. An elastic wave device is used for a filter device, and is provided with a plurality of elastic wave resonators each having a piezoelectric substrate and an IDT electrode. At least one of the plurality of elastic wave resonators is an excitation angle change type resonator. In an excitation angle change resonator, a piezoelectric layer has a propagation axis, and a plurality of electrode fingers are curved. In the excitation angle change resonator, the excitation direction of an elastic wave in an arbitrary portion of any of the plurality of electrode fingers is any one of the first to third directions. In the excitation-angle-variable resonator, when the angle formed by the excitation direction and the direction in which the propagation axis extends is defined as the excitation angle, the excitation angles are different in the IDT electrodes. The plurality of elastic wave resonators are connected to each other in series or in parallel, no other element is provided between the plurality of elastic wave resonators, and the circuit of the filter device between the plurality of elastic wave resonators is not branched.

Description

Technical Field

[0001] The present invention relates to an elastic wave device having a plurality of elastic wave resonators. Background Art

[0002] In the past, elastic wave devices have been widely used in filters of mobile phones, etc. The following patent document 1 discloses an example of a multiplexer in which a plurality of elastic wave resonators are used as series resonators and parallel resonators. The multiplexer has two duplexers. The two duplexers each have two filters. The filters are connected to a common terminal.

[0003] A filter has a plurality of series resonators and a plurality of parallel resonators. In the filter, the series resonator closest to the common terminal is composed of a plurality of split resonators split in series. Each of the split resonators has an IDT (Interdigital Transducer) electrode and a reflector. The plurality of split resonators have at least one of an electrode finger pitch, a cross width, a pair of electrode fingers, a duty cycle, and a distance between an IDT electrode and a reflector that is different from each other.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 003297

[0007] In order to sufficiently suppress unnecessary waves in the multiplexer described in Patent Document 1, it is necessary to divide the series resonators into more series parts. Therefore, the total area of ​​the divided resonators tends to increase. On the other hand, when the number of divided resonators is small, it is difficult to sufficiently suppress unnecessary waves. Summary of the invention

[0008] Problem that the invention aims to solve

[0009] An object of the present invention is to provide an elastic wave device capable of suppressing unnecessary waves.

[0010] Means used to solve problems

[0011] The elastic wave device of the present invention is used for a filter device. The elastic wave device includes a plurality of elastic wave resonators. The plurality of elastic wave resonators respectively include: a piezoelectric substrate having a piezoelectric layer; and an IDT electrode, which is provided on the piezoelectric substrate and has a plurality of electrode fingers. At least one of the plurality of elastic wave resonators is an excitation angle variable resonator. In the excitation angle variable resonator, the piezoelectric layer has a propagation axis, and the plurality of electrode fingers are bent. In the excitation angle variable resonator, the excitation direction of elastic waves in any portion of any electrode finger among the plurality of electrode fingers is any one of a first direction to a third direction, and the first direction is parallel to the first direction. The electrode finger is perpendicular to the direction in which it extends, the second direction is the direction connecting the shortest distance between the electrode finger and the electrode finger adjacent to the electrode finger, the third direction is the direction of the electric field vector generated between the electrode finger and the electrode finger adjacent to the electrode finger, in the excitation angle variable resonator, when the angle formed by the excitation direction and the direction in which the propagation axis extends is set as the excitation angle, in the IDT electrode, the excitation angle is different, the multiple elastic wave resonators are connected in series or in parallel with each other, no other elements are connected between the multiple elastic wave resonators, and the circuit of the filter device is not branched between the multiple elastic wave resonators.

[0012] Effects of the Invention

[0013] According to the elastic wave device according to the present invention, it is possible to suppress unnecessary waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic plan view of the elastic wave device according to the first embodiment of the present invention.

[0015] Figure 2 This is a filter device according to one embodiment of the present invention.

[0016] Figure 3 It is a schematic plan view of the first elastic wave resonator in the first embodiment of the present invention.

[0017] Figure 4 It is along Figure 3 Schematic cross-sectional view of the double-dotted line N in FIG.

[0018] Figure 5 It is a schematic plan view of the second elastic wave resonator in the first embodiment of the present invention.

[0019] Figure 6 It is a schematic top view of an elastic wave device according to a comparative example.

[0020] Figure 7It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment of the present invention and the comparative example.

[0021] Figure 8 It is a schematic plan view of an elastic wave device according to a first modified example of the first embodiment of the present invention.

[0022] Fig. 9 It is a schematic plan view of a first elastic wave resonator in a first modified example of the first embodiment of the present invention.

[0023] Fig.10 This is a schematic plan view showing a circle including an arc when the shape of the electrode fingers of the first IDT electrode in the first modification of the first embodiment of the present invention in a plan view is approximated as an arc.

[0024] Fig.11 It is a schematic plan view of an elastic wave device according to a second modified example of the first embodiment of the present invention.

[0025] Fig.12 It is a schematic plan view of a first elastic wave resonator in a second modified example of the first embodiment of the present invention.

[0026] Fig.13 It is a schematic plan view showing the parallel region and the non-parallel region in the second modification example of the first embodiment of the present invention.

[0027] Fig.14 It is a schematic plan view of a first elastic wave resonator in a third modified example of the first embodiment of the present invention.

[0028] Fig.15 It is a schematic plan view of a first elastic wave resonator in a fourth modified example of the first embodiment of the present invention.

[0029] Fig.16 It is a schematic plan view of a first elastic wave resonator in a fifth modification of the first embodiment of the present invention.

[0030] Fig.17 It is a schematic plan view showing the first edge region and the vicinity of the second edge region in the sixth modification example of the first embodiment of the present invention.

[0031] Fig.18 (a) is a schematic cross-sectional view showing the cross-section of the first electrode finger, the first edge region, the second edge region, and the vicinity of the central region along the direction in which the first electrode finger extends in the seventh variant of the first embodiment of the present invention. Fig.18(b) is a schematic cross-sectional view showing the cross-section of the second electrode finger in the seventh modification example of the first embodiment of the present invention, in the first edge region, the second edge region, and the vicinity of the central region along the direction in which the second electrode finger extends.

[0032] Fig.19 It is a schematic plan view of a first elastic wave resonator in an eighth modification of the first embodiment of the present invention.

[0033] Fig. 20 It is a schematic plan view of an elastic wave device according to a ninth modification example of the first embodiment of the present invention.

[0034] Fig.21 It is a schematic plan view of an elastic wave device according to a second embodiment of the present invention.

[0035] Fig. 22 It is a schematic plan view of an elastic wave device according to a third embodiment of the present invention.

[0036] Fig.23 It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment and the third embodiment of the present invention and the comparative example.

[0037] Fig.24 It is a schematic plan view of an elastic wave device according to a first modified example of the third embodiment of the present invention.

[0038] Fig.25 It is a schematic plan view of an elastic wave device according to a second modified example of the third embodiment of the present invention.

[0039] Fig.26 It is a diagram showing phase characteristics near the frequency at which unnecessary waves are generated in the first embodiment of the present invention, the second modification of the third embodiment, and the comparative example.

[0040] Fig. 27 It is a schematic plan view of an elastic wave device according to a third modified example of the third embodiment of the present invention.

[0041] Fig.28 It is a schematic plan view of an elastic wave device according to a fourth embodiment of the present invention.

[0042] Fig.29 It is a schematic plan view of an elastic wave device according to a modified example of the fourth embodiment of the present invention.

[0043] Fig.30 It is a schematic plan view of an elastic wave device according to a fifth embodiment of the present invention.

[0044] Fig.31It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment and the fifth embodiment of the present invention and the comparative example.

[0045] Fig.32 It is a schematic plan view of an elastic wave device according to a modified example of the fifth embodiment of the present invention.

[0046] Fig.33 It is a schematic front cross-sectional view of an elastic wave device according to a sixth embodiment of the present invention.

[0047] Fig.34 It is a schematic front cross-sectional view of an elastic wave device according to a first modified example of the sixth embodiment of the present invention.

[0048] Fig.35 It is a schematic front cross-sectional view of an elastic wave device according to a second modified example of the sixth embodiment of the present invention.

[0049] Fig.36 It is a schematic front cross-sectional view of an elastic wave device according to a seventh embodiment of the present invention.

[0050] Fig.37 It is a schematic front cross-sectional view of an elastic wave device according to an eighth embodiment of the present invention.

[0051] Fig.38 It is a schematic front cross-sectional view of an elastic wave device according to a first modified example of the eighth embodiment of the present invention.

[0052] Fig.39 It is a schematic front cross-sectional view of an elastic wave device according to a second modified example of the eighth embodiment of the present invention.

[0053] Fig.40 It is a schematic front cross-sectional view of an elastic wave device according to a third modified example of the eighth embodiment of the present invention.

[0054] Description of Reference Numerals

[0055] 1...Elastic wave device;

[0056] 1A, 1B...a first elastic wave resonator, a second elastic wave resonator;

[0057] 1C, 1D, 1J...1st elastic wave resonator;

[0058] 2...Piezoelectric substrate;

[0059] 3...supporting member;

[0060] 4...support base plate;

[0061] 5...Middle layer;

[0062] 5a, 5b...1st layer, 2nd layer;

[0063] 6...Piezoelectric layer;

[0064] 6a, 6b...1st main surface, 2nd main surface;

[0065] 7A...Input terminal;

[0066] 7B...output terminal;

[0067] 8... Dielectric film;

[0068] 9A~9H...Reflector;

[0069] 9a, 9b...reflector busbar;

[0070] 9c...reflector electrode finger;

[0071] 9d, 9e...reflector busbar;

[0072] 9f...reflector electrode finger;

[0073] 10...Filter device;

[0074] 12A...1st offset electrode;

[0075] 12B... third offset electrode;

[0076] 12D, 12I...a first offset electrode;

[0077] 13A...second offset electrode;

[0078] 13B...4th offset electrode;

[0079] 13D, 13I...a second offset electrode;

[0080] 14A, 15A...1st bus bar, 2nd bus bar;

[0081] 16A...1st electrode finger;

[0082] 16B...the third electrode finger;

[0083] 16C, 16D, 16F to 16H...1st electrode finger;

[0084] 16a, 16b ... wide width portion;

[0085] 17A...second electrode finger;

[0086] 17B...the fourth electrode finger;

[0087] 17C, 17D, 17F to 17H...second electrode finger;

[0088] 17a, 17b ... wide width portion;

[0089] 18A, 18B...a first IDT electrode, a second IDT electrode;

[0090] 18C~18J...1st IDT electrode;

[0091] 19...Quality additional film;

[0092] 21...Elastic wave device;

[0093] 21B...2nd elastic wave resonator;

[0094] 28B...second IDT electrode;

[0095] 31...Elastic wave device;

[0096] 31A, 31C...a first elastic wave resonator;

[0097] 31D...2nd elastic wave resonator;

[0098] 31J...1st elastic wave resonator;

[0099] 41A, 41C, 41J...a second elastic wave resonator;

[0100] 51...Elastic wave device;

[0101] 51C, 51D...the third elastic wave resonator;

[0102] 62, 62A, 62B ... piezoelectric substrate;

[0103] 62c...Hollow part;

[0104] 64...support base plate;

[0105] 65, 65A...middle layer;

[0106] 67...Sound reflection film;

[0107] 67a...high acoustic impedance layer;

[0108] 67b...low acoustic impedance layer;

[0109] 67c...high acoustic impedance layer;

[0110] 67d...Low acoustic impedance layer;

[0111] 67e...high acoustic impedance layer;

[0112] 79...Protective film;

[0113] 79a, 79b...a first protective layer, a second protective layer;

[0114] 81...Elastic wave device;

[0115] 88...Electrode;

[0116] 101A, 101B: a first elastic wave resonator, a second elastic wave resonator;

[0117] A...parallel area;

[0118] B...non-parallel region;

[0119] D...node;

[0120] E1, E1C...1st envelope;

[0121] E2, E2C...Second envelope;

[0122] E3, E4...the 3rd envelope, the 4th envelope;

[0123] F...Central Region;

[0124] H1, H2...1st marginal area, 2nd marginal area;

[0125] J...intersection area;

[0126] K1, K2...1st curve area, 2nd curve area;

[0127] P...Parallel arm;

[0128] P1, P2...parallel arm resonator part;

[0129] S...tandem arm;

[0130] S2, S3...series arm resonator section;

[0131] V1, V2...bending part;

[0132] W1~W3...Area 1 to Area 3. DETAILED DESCRIPTION

[0133] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings to clarify the present invention.

[0134] In addition, it should be noted that each embodiment described in this specification is an example, and some structures can be replaced or combined between different embodiments.

[0135] Figure 1 FIG. 1 is a schematic top view of an elastic wave device according to a first embodiment of the present invention. Figure 1 In FIG. 1 , an IDT electrode and a reflector to be described later are represented by a graph including a curved line and a simplified diagram in which two diagonal lines are added to a rectangle.

[0136] Figure 1 The elastic wave device 1 shown is used as a part of a filter device. The elastic wave device 1 includes a plurality of elastic wave resonators. In the present embodiment, the plurality of elastic wave resonators are specifically a first elastic wave resonator 1A and a second elastic wave resonator 1B.

[0137] Figure 2 This is a filter device according to one embodiment of the present invention.

[0138] The filter device 10 is a ladder filter. The filter device 10 includes a plurality of series arm resonators and a plurality of parallel arm resonators. The first elastic wave resonator 1A and the second elastic wave resonator 1B in the first embodiment are split resonators that are split in series. That is, the first elastic wave resonator 1A and the second elastic wave resonator 1B are connected in series with each other, and no other element is connected between the first elastic wave resonator 1A and the second elastic wave resonator 1B. Furthermore, the circuit of the filter device 10 is not branched between the first elastic wave resonator 1A and the second elastic wave resonator 1B.

[0139] In addition, first elastic wave resonator 1A and second elastic wave resonator 1B may be, for example, split resonators split in parallel. In filter device 10, first elastic wave resonator 1A and second elastic wave resonator 1B are series arm resonators. However, first elastic wave resonator 1A and second elastic wave resonator 1B may be parallel arm resonators split in series or in parallel.

[0140] The plurality of elastic wave resonators of the elastic wave device according to the present invention may be resonators having a circuit configuration equivalent to that of a split resonator. For example, the resonance frequencies of the plurality of elastic wave resonators may not be consistent with each other.

[0141] The first elastic wave resonator 1A in the elastic wave device 1 is an excitation angle variable resonator, which will be described in detail later. On the other hand, the second elastic wave resonator 1B is an elastic wave resonator that is not an excitation angle variable resonator. In addition, the elastic wave device according to the present invention only needs to have at least two elastic wave resonators. The plurality of elastic wave resonators only needs to include at least one excitation angle variable resonator. The specific structure of the elastic wave device 1 in the first embodiment is described below.

[0142] Figure 3 FIG. 1 is a schematic plan view of the first elastic wave resonator according to the first embodiment. Figure 4 It is along Figure 3 Schematic cross-sectional view of the double-dotted line N in FIG.

[0143] like Figure 3 as well as Figure 4 As shown in FIG. 1 , the first elastic wave resonator 1A includes a piezoelectric substrate 2. Figure 4 As shown, the piezoelectric substrate 2 is a stacked substrate including a piezoelectric layer 6. That is, the piezoelectric substrate 2 is a substrate having piezoelectricity. Specifically, the piezoelectric substrate 2 has a supporting member 3 and a piezoelectric layer 6. More specifically, the supporting member 3 has a supporting substrate 4 and an intermediate layer 5. The intermediate layer 5 includes a first layer 5a and a second layer 5b. The first layer 5a is provided on the supporting substrate 4. The second layer 5b is provided on the first layer 5a. The piezoelectric layer 6 is provided on the second layer 5b. In addition, the layer structure of the piezoelectric substrate 2 is not limited to the above. For example, the intermediate layer 5 may also be a single-layer dielectric layer. Alternatively, the piezoelectric substrate 2 may also be a substrate including only the piezoelectric layer 6.

[0144] In the first embodiment, silicon is used as the material of the support substrate 4. Silicon nitride is used as the material of the first layer 5a. Silicon oxide is used as the material of the second layer 5b. Lithium tantalate that rotates Y-cut and propagates X-propagation is used as the material of the piezoelectric layer 6. In this way, the piezoelectric layer 6 has a propagation axis. And the direction of the propagation axis is the X direction. However, the materials of each layer of the piezoelectric substrate 2 are not limited to the above.

[0145] The piezoelectric layer 6 has a first main surface 6a and a second main surface 6b. The first main surface 6a and the second main surface 6b are opposite to each other. Of the first main surface 6a and the second main surface 6b, the second main surface 6b is located on the support substrate 4 side. A first IDT electrode 18A is provided on the first main surface 6a of the piezoelectric layer 6. Thus, a first elastic wave resonator 1A is formed.

[0146] like Figure 3As shown, the first IDT electrode 18A has a pair of bus bars and a plurality of electrode fingers. The pair of bus bars is specifically the first bus bar 14A and the second bus bar 15A. The first bus bar 14A and the second bus bar 15A are opposite to each other. The plurality of electrode fingers are specifically the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A. One end of the plurality of first electrode fingers 16A is respectively connected to the first bus bar 14A. One end of the plurality of second electrode fingers 17A is respectively connected to the second bus bar 15A.

[0147] The plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A respectively include a base end portion, a front end portion, and a pair of end edges. Specifically, the base end portion of the first electrode finger 16A is a portion connected to the first bus bar 14A. The pair of end edges of the first electrode finger 16A is a portion connecting the base end portion and the front end portion. The base end portion of the second electrode finger 17A is a portion connected to the second bus bar 15A. The pair of end edges of the second electrode finger 17A is a portion connecting the base end portion and the front end portion in a plan view. The plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A are interlaced with each other. In addition, in this specification, the so-called plan view refers to the view from the direction opposite to the first bus bar 14A. Figure 4 Observe from the upper direction. Figure 4 For example, between the support substrate 4 side and the piezoelectric layer 6 side, the piezoelectric layer 6 side is at the upper side.

[0148] The front ends of the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A respectively include front ends. A virtual line formed by connecting the front ends of the plurality of second electrode fingers 17A is set as the first envelope E1. Similarly, a virtual line formed by connecting the front ends of the plurality of first electrode fingers 16A is set as the second envelope E2. In addition, hereinafter, the first electrode fingers 16A and the second electrode fingers 17A are sometimes recorded as simply electrode fingers. The first bus bar 14A and the second bus bar 15A are sometimes recorded as simply bus bars.

[0149] The area between the first envelope E1 and the second envelope E2 is the intersection area J. More specifically, the area surrounded by the edge of the electrode finger at one end in the direction in which the plurality of electrode fingers are arranged, the edge of the electrode finger at the other end, the first envelope E1, and the second envelope E2 is the intersection area J. Therefore, the first envelope E1 corresponds to the edge on the first bus bar 14A side of the intersection area J. The second envelope E2 corresponds to the edge on the second bus bar 15A side of the intersection area J. In the intersection area J, when viewed from the direction in which the first envelope E1 or the second envelope E2 extends, adjacent electrode fingers overlap each other.

[0150] In the first embodiment, the intersection region J is composed of a curved region. The so-called curved region refers to a region where the shapes of the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A are curved when viewed from above. One end edge of the curved region constituting the intersection region J is the first envelope E1. The other end edge is the second envelope E2. However, in the first elastic wave resonator 1A as an excitation angle variable resonator, the plurality of electrode fingers may be bent. For example, the shape of the plurality of electrode fingers when viewed from above may also be a shape bent at a plurality of sections.

[0151] By applying an AC voltage to the first IDT electrode 18A, elastic waves are excited in the intersection region J. More specifically, for example, the SH mode is excited as the main mode. In this case, Rayleigh waves become unnecessary waves. However, the main mode is not limited to the SH mode.

[0152] As described above, the intersection region J of the first IDT electrode 18A is a curved region. The shape of each electrode finger in the curved region is a curved shape in a plan view. Therefore, the excitation direction of the elastic wave is different in the curved region of the first IDT electrode 18A.

[0153] like Figure 3 As shown, the shapes of the first electrode fingers 16A and the second electrode fingers 17A of the first IDT electrode 18A when viewed from above are arc shapes. Specifically, the shapes of the plurality of electrode fingers when viewed from above are shapes corresponding to the respective arcs in the plurality of concentric circles. Therefore, the centers of the circles containing the arcs in the shapes of the plurality of electrode fingers are consistent. The center is set as a fixed point C.

[0154] In addition, the shapes of the multiple electrode fingers of the first IDT electrode 18A are not limited to the above. In the case where the intersection region J includes a curved region, the shape of the multiple electrode fingers of the first IDT electrode 18A when viewed from above only needs to be a curved shape in the curved region. The shape of the multiple electrode fingers of the first IDT electrode 18A when viewed from above may be, for example, an elliptical arc shape, or a curved shape other than a circular arc and an elliptical arc. Alternatively, the intersection region J may not include a curved region, and the shape of the multiple electrode fingers when viewed from above may be a shape that is bent at multiple nodes.

[0155] In the first embodiment, the direction in which the curved portion of the electrode finger protrudes in the direction in which the plurality of electrode fingers are arranged is the outer direction. Specifically, Figure 3 The right direction in is the outer direction of first elastic wave resonator 1A. The direction opposite to the outer direction is the inner direction. More specifically, the direction in which the curved portion of the electrode finger is recessed in the direction in which the plurality of electrode fingers are arranged is the inner direction. Figure 3The left direction in is the inner direction of first elastic wave resonator 1A. The same is true when the plurality of electrode fingers are bent at a plurality of sections in a plan view. The direction in which the bent portion of the electrode finger protrudes in the direction in which the plurality of electrode fingers are arranged is the outer direction.

[0156] When the ellipticity coefficient of the circle or ellipse of the arc in the shape including the plurality of electrode fingers is set to α2 / α1, the ellipticity coefficient α2 / α1 in the first embodiment is 1. α1 corresponds to the dimension of the ellipse along the direction of the axis passing through the intersection region J among the major axis and the minor axis. α2 corresponds to the dimension of the ellipse along the direction of the axis not passing through the intersection region J among the major axis and the minor axis.

[0157] As described above, the piezoelectric layer 6 has a propagation axis. The direction in which the propagation axis extends is Figure 3 The first envelope E1 is parallel to the direction in which the double-dotted dash line N in FIG. extends. The first envelope E1 is linear and inclined relative to the propagation axis. Similarly, the second envelope E2 is linear and inclined relative to the propagation axis. The direction in which the first envelope E1 extends intersects the direction in which the second envelope E2 extends. The first envelope E1 and the second envelope E2 are arranged to be line-symmetrical with respect to an axis of symmetry passing through the center of the intersection region J. In the first embodiment, the axis of symmetry is parallel to the direction in which the propagation axis extends.

[0158] In addition, the shapes and arrangements of the first envelope E1 and the second envelope E2 are not limited to those described above. In the present invention, at least one of the first envelope E1 and the second envelope E2 may be other than a straight line, or at least one of them may be a straight line.

[0159] Figure 5 It is a schematic plan view of the second elastic wave resonator in the first embodiment.

[0160] The second elastic wave resonator 1B shares the first elastic wave resonator 1A and the piezoelectric substrate 2. The second elastic wave resonator 1B is an elastic wave resonator that is not an excitation angle variable resonator. Therefore, in the first embodiment, the piezoelectric layer 6 has a propagation axis in both the first elastic wave resonator 1A that is an excitation angle variable resonator and the second elastic wave resonator 1B that is not an excitation angle variable resonator. The second elastic wave resonator 1B has a second IDT electrode 18B. The second IDT electrode 18B is provided on the first principal surface 6a of the piezoelectric layer 6 in the piezoelectric substrate 2.

[0161] The second IDT electrode 18B has a pair of bus bars and a plurality of electrode fingers. Specifically, the plurality of electrode fingers of the second IDT electrode 18B are a plurality of third electrode fingers 16B and a plurality of fourth electrode fingers 17B. The third electrode fingers 16B and the fourth electrode fingers 17B are linear in plan view.

[0162] The plurality of third electrode fingers 16B and the plurality of fourth electrode fingers 17B respectively include a base end portion, a front end portion, and a pair of end edges, similarly to each electrode finger of the first IDT electrode 18A. The base ends of the plurality of third electrode fingers 16B are respectively connected to one bus bar. The base ends of the plurality of fourth electrode fingers 17B are respectively connected to another bus bar. The plurality of third electrode fingers 16B and the plurality of fourth electrode fingers 17B are interlaced with each other.

[0163] A virtual line formed by connecting the front ends of the plurality of fourth electrode fingers 17B is set as the third envelope E3. Similarly, a virtual line formed by connecting the front ends of the plurality of third electrode fingers 16B is set as the fourth envelope E4. The second IDT electrode 18B has an intersection region. The intersection region is a region between the third envelope E3 and the fourth envelope E4. In the intersection region, when viewed from the direction in which the third envelope E3 or the fourth envelope E4 extends, adjacent electrode fingers overlap each other.

[0164] The third envelope E3 and the fourth envelope E4 are linear. The third envelope E3 and the fourth envelope E4 extend in parallel with the direction in which the propagation axis of the piezoelectric layer 6 extends. The second IDT electrode 18B is a so-called regular IDT electrode.

[0165] The first embodiment is characterized in having the following structure. 1) Multiple elastic wave resonators include an excitation angle variable resonator. 2) Multiple elastic wave resonators are connected in series or in parallel with each other, no other elements are connected between the multiple elastic wave resonators, and the circuit of the filter device is not branched between the multiple elastic wave resonators. As described above, the elastic wave device 1 of the first embodiment is used in a filter device. In the circuit structure of the filter device, the multiple elastic wave resonators are equivalent to split resonators in which one resonator is split in series. The split resonator includes an excitation angle variable resonator. In this way, useless waves can be suppressed. The details thereof are described below together with the details of the structure of the first embodiment and the details of the excitation angle and the excitation angle variable resonator.

[0166] Figure 3 The excitation direction of the elastic wave in any portion of any electrode finger among the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A in the intersection region J shown is any one of the following first to third directions. The first direction is a direction perpendicular to the direction in which the electrode finger extends. The second direction is a direction connecting the shortest distance between the electrode finger and the first electrode finger 16A or the second electrode finger 17A adjacent to the electrode finger. The third direction is a direction of an electric field vector generated between the electrode finger and the first electrode finger 16A or the second electrode finger 17A adjacent to the electrode finger.

[0167] In addition, since the shape of each electrode finger in the intersection region J is a curved shape, the direction in which one electrode finger extends differs at each position. In this specification, unless otherwise specified, the direction in which the curved electrode finger extends is defined as follows.

[0168] First, a pair of end edges of each electrode finger has a curved shape. In any part of the electrode finger, when a virtual line parallel to the direction in which the propagation axis extends is drawn to connect the two end edges, the center of gravity of the part located on the virtual line is set as the representative point on the virtual line. Countless virtual lines can be drawn on the electrode finger, and there are countless representative points. The direction in which the tangent of the curve connecting these representative points extends is set as the direction in which the electrode finger extends.

[0169] The angle formed by the excitation direction of the elastic wave and the direction in which the propagation axis of the piezoelectric layer 6 extends is defined as an excitation angle θ. C_prop The excitation angle variable resonator in the present invention refers to a resonator in which the excitation angle θ in the intersection region J is C_prop In other words, in the intersection region J of the excitation angle variation type resonator, the excitation angle θ C_prop no the same.

[0170] In the first embodiment, the direction in which the propagation axis extends is Figure 3 The double-dotted line N in FIG. 1 is parallel to the direction in which the double-dotted line N in FIG. 1 extends. The double-dotted line N is a straight line passing through the fixed point C and the intersection region J. The fixed point C is defined based on the shape of the plurality of electrode fingers when viewed from above. Specifically, in the first embodiment, the centers of the circles containing the arcs in the shape of the plurality of electrode fingers coincide. The center is the fixed point C. In the portion indicated by the double-dotted line N, the excitation angle θ C_prop is 0°. Excitation angle θ C_prop The portion at 0° is arranged in a straight line.

[0171] Likewise, if Figure 3 As shown in the straight line M in the figure, in the first embodiment, when the excitation angle θ is C_prop is other than 0° and the excitation angle θ C_prop When the same parts are connected, they also become a straight line. This straight line M is a straight line passing through the fixed point C and the intersection area J.

[0172] in addition, Figure 3 The straight line M in is an example of a straight line passing through the fixed point C and the intersection region J. That is, the portion of the intersection region J located on the straight line M is the excitation angle θ C_prop is other than 0° and the excitation angle θ C_propAn example of the same part. There are countless straight lines passing through the fixed point C and the intersection region J. Moreover, the part located on countless straight lines (not shown) in the intersection region J has the same excitation angle θ as the part located on the straight line M. C_prop is other than 0° and the excitation angle θ C_prop However, in these straight lines, the excitation angle θ C_prop As described above, the shapes of the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A in a plan view are set to the excitation angle θ C_prop is other than 0° and the excitation angle θ C_prop The same parts are arranged in a straight line shape.

[0173] In this specification, the excitation angle θ C_prop The positive direction is the counterclockwise direction in a plan view. More specifically, the direction from the second bus bar 15A side toward the first bus bar 14A side is the positive direction.

[0174] When the straight line passing through the center of the intersection region J is set as the reference line, in the first embodiment, the two-dot chain line N coincides with the reference line. In addition, the reference line may not necessarily extend parallel to the direction in which the propagation axis extends. The angle formed by the straight line passing through the first envelope E1 and the fixed point C and the reference line is set as the intersection angle θ C1_AP The angle formed by the straight line passing through the second envelope E2 and the fixed point C and the reference line is defined as the intersection angle θ. C2_AP In this case, θ C_AP2 ≤θ C_prop ≤θ C_AP1 In the first embodiment, the intersection angle θ C_AP1 and the intersection angle θ C_AP2 The absolute value of is the same. Therefore, the excitation angle θ C_prop The absolute value of is 0°≤|θ C_prop |≤|θ C_AP1 |=|θ C_AP2 |.

[0175] In the first IDT electrode 18A of the first embodiment, at the excitation angle θ C_prop The electrode finger pitch and duty ratio are constant for the same parts. The electrode finger pitch refers to the distance between the centers of the adjacent first electrode fingers 16A and second electrode fingers 17A. When the wavelength defined by the electrode finger pitch of the first IDT electrode 18A is λ and the electrode finger pitch is p, λ=2p.

[0176] In the first IDT electrode 18A of the first elastic wave resonator 1A, the duty ratio is changed according to the excitation angle θ. C_propSpecifically, the duty cycle changes at the excitation angle θ C_prop The part with a value of 0° is the maximum value, and the absolute value of the excitation angle |θ C_prop |The larger the value, the smaller the duty cycle. However, this is not limited to this.

[0177] like Figure 3 As shown, the first IDT electrode 18A has a plurality of offset electrodes. Specifically, the plurality of offset electrodes of the first IDT electrode 18A are a plurality of first offset electrodes 12A and a plurality of second offset electrodes 13A. One ends of the plurality of first offset electrodes 12A are respectively connected to the first bus bar 14A. The first electrode fingers 16A and the first offset electrodes 12A are arranged alternately. One ends of the plurality of second offset electrodes 13A are respectively connected to the second bus bar 15A. The second electrode fingers 17A and the second offset electrodes 13A are arranged alternately.

[0178] Similar to the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A, the plurality of first offset electrodes 12A and the plurality of second offset electrodes 13A each include a base end portion and a front end portion. The base end portions of the first electrode fingers 16A and the first offset electrodes 12A are portions connected to the first bus bar 14A. The base end portions of the second electrode fingers 17A and the second offset electrodes 13A are portions connected to the second bus bar 15A. The front end portions of the first electrode fingers 16A and the front end portions of the second offset electrodes 13A are opposed to each other with a gap therebetween. The front end portions of the second electrode fingers 17A and the front end portions of the first offset electrodes 12A are opposed to each other with a gap therebetween.

[0179] Hereinafter, the first offset electrode 12A and the second offset electrode 13A may be simply described as offset electrodes. The shapes of the plurality of offset electrodes in a plan view each include a curved portion. In addition, a plurality of first offset electrodes 12A and a plurality of second offset electrodes 13A may not necessarily be provided.

[0180] A pair of reflectors 9A and 9B are provided on the piezoelectric layer 6. The reflectors 9A and 9B face each other across the first IDT electrode 18A in the direction in which the plurality of electrode fingers of the first IDT electrode 18A are arranged.

[0181] The reflector 9A includes a pair of reflector bus bars 9a and a reflector bus bar 9b. The reflector bus bars 9a and the reflector bus bars 9b are opposed to each other. The reflector 9A includes a plurality of reflector electrode fingers 9c. One end of each of the plurality of reflector electrode fingers 9c is connected to the reflector bus bar 9a. The other ends of each of the plurality of reflector electrode fingers 9c are connected to the reflector bus bar 9b. The shapes of the plurality of reflector electrode fingers 9c of the reflector 9A in a plan view each include a curved shape.

[0182] Similarly, the reflector 9B has a pair of reflector bus bars 9d and a reflector bus bar 9e, and a plurality of reflector electrode fingers 9f. The first IDT electrode 18A, the reflector 9A, and the reflector 9B include a single-layer metal film. Specifically, in the first embodiment, Al is used as the material of the first IDT electrode 18A, the reflector 9A, and the reflector 9B. In addition, the materials of the first IDT electrode 18A, the reflector 9A, and the reflector 9B are not limited to the above. Alternatively, the first IDT electrode 18A, the reflector 9A, and the reflector 9B may also include a laminated metal film.

[0183] In addition, if Figure 5 As shown, the second IDT electrode 18B of the second elastic wave resonator 1B also has a plurality of offset electrodes. Specifically, the plurality of offset electrodes of the second IDT electrode 18B are a plurality of third offset electrodes 12B and a plurality of fourth offset electrodes 13B. The third offset electrodes 12B and the fourth offset electrodes 13B are linear in plan view.

[0184] Second elastic wave resonator 1B includes a pair of reflectors 9C and 9D. The shape of each reflector electrode finger of each reflector in a plan view is a linear shape.

[0185] In the piezoelectric layer 6 of the elastic wave device 1, the direction in which the propagation axis extends is the X propagation direction. However, the present invention is not limited thereto. The direction in which the propagation axis extends may be, for example, the 90° X propagation direction, or may be a direction perpendicular to any direction in which the electrode fingers in the first IDT electrode 18A extend.

[0186] like Figure 4 As shown, a dielectric film 8 is provided on the piezoelectric layer 6 so as to cover the first IDT electrode 18A. Since the first IDT electrode 18A is protected by the dielectric film 8, the first IDT electrode 18A is not easily damaged. Although not shown, the second IDT electrode 18B is also covered by the dielectric film 8. In the first embodiment, silicon oxide is provided as a material of the dielectric film 8. In addition, the material of the dielectric film 8 is not limited to the above. In the first embodiment, the thickness of the dielectric film 8 is fixed. In addition, the dielectric film 8 may not necessarily be provided.

[0187] As described above, the plurality of elastic wave resonators of the elastic wave device 1 include an excitation angle-variable resonator, thereby making it possible to suppress unnecessary waves. This will be described below by comparing the first embodiment and the comparative example.

[0188] like Figure 6As shown, the difference between the comparative example and the first embodiment is that first elastic wave resonator 101A and second elastic wave resonator 101B are both so-called normal elastic wave resonators. That is, the plurality of elastic wave resonators of the comparative example do not include an excitation angle variable resonator. The phase characteristics of the elastic wave device having the structure of the first embodiment and the elastic wave device of the comparative example are compared.

[0189] The design parameters of the elastic wave resonator having the structure of the first elastic wave resonator 1A as an excitation angle variable resonator are as follows. Here, the dimension of the offset electrode along the direction connecting the base end and the front end is defined as the length of the offset electrode. The dimension of the gap between the front end of the electrode finger and the front end of the offset electrode along the direction in which the electrode finger and the offset electrode are opposed is defined as the gap length. In the first embodiment, the gap between the front end of the second electrode finger 17A and the front end of the first offset electrode 12A and the gap between the front end of the first electrode finger 16A and the front end of the second offset electrode 13A have the same gap length.

[0190] Support substrate 4: Material...Si, Surface orientation...(111), Euler angles ( ,θ,ψ) in which ψ...73°

[0191] First layer 5a of the intermediate layer 5: material ... SiN, thickness ... 0.15λ

[0192] Second layer 5b of the intermediate layer 5: material ... SiO2, thickness ... 0.15λ

[0193] Piezoelectric layer 6: Material... Rotated Y-cut 55° X-propagated LiTaO3, thickness... 0.2λ

[0194] First IDT electrode 18A: material...Al, thickness...0.05λ

[0195] Dielectric film 8: Material...SiO2, Thickness...0.015λ

[0196] Crossing angle θ C1_AP : 5°

[0197] Crossing angle θ C2_AP : -5°

[0198] Wavelength λ: at excitation angle θ C_prop The 0° portion is 2 μm

[0199] Number of pairs of electrode fingers of the first IDT electrode 18A: 80 pairs

[0200] Duty cycle: At the excitation angle θ C_propThe part with a value of 0° is 0.5, and the absolute value of the excitation angle |θ C_prop |The larger it is, the smaller the duty cycle is.

[0201] Gap length: 0.135λ

[0202] Length of offset electrode: 3.5λ

[0203] Reflector 9A and reflector 9B: Number of pairs of reflector electrode fingers: 20 pairs

[0204] In the elastic wave resonator having the structure of second elastic wave resonator 1B, the duty ratio is 0.5 and is fixed. In each of the elastic wave resonators of the comparative examples, the duty ratio is also 0.5 and is also fixed.

[0205] Figure 7 It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment and the comparative example.

[0206] like Figure 7 As shown, it can be seen that in the first embodiment, the Rayleigh wave, which is an unnecessary wave, can be suppressed compared with the comparative example. In this way, when the elastic wave devices of the first embodiment and the comparative example have the same number of elastic wave resonators, in the first embodiment, the unnecessary wave can be suppressed compared with the comparative example. Therefore, in the first embodiment, it is not necessary to increase the number of elastic wave resonators in order to suppress the unnecessary wave. Therefore, in the first embodiment, the unnecessary wave can be suppressed without causing the size of the filter device used to be increased.

[0207] Since the plurality of elastic wave resonators of the elastic wave device 1 include the first elastic wave resonator 1A as an excitation angle variation type resonator, unnecessary waves can be suppressed in the elastic wave device 1 . This is based on the following reason.

[0208] exist Figure 3 In the intersection region J of the first elastic wave resonator 1A shown in FIG. C_prop is other than 0° and the excitation angle θ C_prop Numerous identical linear portions are arranged in the direction in which the first bus bar 14A and the second bus bar 15A face each other. C_prop Different from each other. At the excitation angle θ C_prop In different parts, the propagation characteristics of the useless waves are different from each other. As a result, the useless waves can be dispersed and effectively suppressed. In particular, the useless waves outside the frequency band such as Rayleigh waves can be suppressed. In this specification, the so-called outside the frequency band in the elastic wave device refers to the low frequency side of the resonant frequency and the high frequency side of the anti-resonant frequency.

[0209] In the first elastic wave resonator 1A, the first envelope E1 and the second envelope E2 extend obliquely with respect to the propagation axis of the piezoelectric layer 6. This can suppress the transverse mode. The transverse mode is an unnecessary wave generated between the resonant frequency and the antiresonant frequency. However, the first envelope E1 and the second envelope E2 may extend parallel to the direction in which the propagation axis extends.

[0210] In the first embodiment, an example is shown in which the second elastic wave resonator 1B is an elastic wave resonator that is not an excitation angle variable resonator. In the first embodiment, the number of excitation angle variable resonators is one. However, the elastic wave device 1 may have two or more excitation angle variable resonators. Alternatively, all elastic wave resonators of the elastic wave device 1 may be excitation angle variable resonators.

[0211] Below, using Figure 2 The relationship between the elastic wave device according to the present invention and a filter device using the elastic wave device will be described in detail.

[0212] like Figure 2 As shown, the filter device 10 is a ladder-type filter.

[0213] The filter device 10 has an input terminal 7A and an output terminal 7B, a plurality of series arm resonators, and a plurality of parallel arm resonators. In the circuit structure of the filter device 10, a series arm S, a plurality of parallel arms P, and a plurality of nodes D are provided. The series arm S is a path connecting the input terminal 7A and the output terminal 7B. Each series arm resonator is provided in the series arm S. On the other hand, each parallel arm P is a path branched from the series arm S to each ground terminal. Each parallel arm resonator is provided in each parallel arm P. On the other hand, the node D is a connection point between the series arm S and the parallel arm P.

[0214] The filter device 10 includes a plurality of series arm resonator sections. The series arm resonator section is one series arm resonator or a group of a plurality of series arm resonators connected in series or in parallel to each other without passing through a node D. More specifically, the series arm resonator section is a portion where one or more series arm resonators are provided between the input terminal 7A and the node D, between the nodes D, or between the node D and the output terminal 7B.

[0215] exist Figure 2In the example shown, the elastic wave device 1 of the first embodiment is a series arm resonator unit. Moreover, the first elastic wave resonator 1A and the second elastic wave resonator 1B are two series arm resonators in one series arm resonator unit. The series arm resonator unit is composed of only one or more series arm resonators. Therefore, no other elements are arranged between the multiple elastic wave resonators of the elastic wave device 1. No node D or other branching points are arranged between the multiple series arm resonators in one series arm resonator unit. Therefore, the circuit of the filter device 10 does not branch between the multiple elastic wave resonators of the elastic wave device 1.

[0216] In addition, the filter device 10 includes a plurality of series arm resonator sections other than the elastic wave device 1. Specifically, these series arm resonator sections are a series arm resonator section S2 and a series arm resonator section S3. From the input terminal 7A side, the elastic wave device 1, the series arm resonator section S2, and the series arm resonator section S3 are connected in series with each other in this order. The series arm resonator section S2 and the series arm resonator section S3 each include one series arm resonator.

[0217] In filter device 10, elastic wave device 1 is a series arm resonator portion located closest to input terminal 7A. However, the configuration of elastic wave device 1 in filter device 10 is not limited to the above. For example, elastic wave device 1 may be a series arm resonator portion located closest to output terminal 7B in filter device 10, or may be a series arm resonator portion located neither closest to input terminal 7A nor closest to output terminal 7B.

[0218] The filter device 10 has a plurality of parallel arm resonator sections. The parallel arm resonator section is one parallel arm resonator or a group of a plurality of parallel arm resonators connected in series or in parallel to each other in the parallel arm P. The parallel arm resonator section may also be a section including a plurality of split-type parallel arm resonators. In the following, the series arm resonator section and the parallel arm resonator section may be collectively described as a resonator section.

[0219] The plurality of parallel arm resonator sections of the filter device 10 are specifically a parallel arm resonator section P1 and a parallel arm resonator section P2. All parallel arm resonator sections of the filter device 10 include one parallel arm resonator. The parallel arm resonator section P1 is connected between a node D between the elastic wave device 1 and the series arm resonator section S2 and a ground potential. The parallel arm resonator section P2 is connected between a node D between the series arm resonator section S2 and the series arm resonator section S3 and a ground potential.

[0220] The elastic wave device 1 may also be a parallel arm resonator section equivalent to the parallel arm resonator section P1. In this case, the first elastic wave resonator 1A and the second elastic wave resonator 1B are two parallel arm resonators in one parallel arm resonator section. The parallel arm resonator section is composed of only one or more parallel arm resonators. Therefore, no other elements are arranged between the multiple elastic wave resonators of the elastic wave device 1. No node D or other branching points are arranged between the multiple parallel arm resonators in one parallel arm resonator section. Therefore, even in the case where the elastic wave device 1 is equivalent to the parallel arm resonator section P1, the circuit of the filter device 10 does not branch between the multiple elastic wave resonators.

[0221] That is, the elastic wave device according to the present invention is a resonator unit in a filter device. The elastic wave device as a resonator unit includes a plurality of elastic wave resonators, and the plurality of elastic wave resonators includes at least one excitation angle variable resonator. In the elastic wave device, the plurality of elastic wave resonators may be connected in series or in parallel.

[0222] In the first embodiment, the resonant frequencies of the main modes of the first elastic wave resonator 1A are substantially identical in all the intersection regions J. Specifically, in the first elastic wave resonator 1A, the duty ratio is changed according to the excitation angle θ. C_prop As a result, the resonance frequencies in all the intersection regions J are made substantially uniform.

[0223] The excitation angle θ of the excitation angle variable resonator C_prop In the mutually different parts, the relationship between the resonant frequencies of the main mode and the unwanted waves and the relationship between the anti-resonant frequencies are different from each other. Moreover, in the first elastic wave resonator 1A as an excitation angle variable resonator, the resonant frequencies of the main mode are consistent with each other in all the intersection regions J. Therefore, the frequencies of the unwanted waves are different from each other. As a result, the unwanted waves outside the frequency band are dispersed. Therefore, the unwanted waves outside the frequency band such as Rayleigh waves can be further suppressed.

[0224] Furthermore, since the resonance frequencies in the intersection region J are substantially consistent with each other, the main mode can be appropriately excited. Therefore, the resonance characteristics can be improved more reliably. Thus, the filter characteristics of the filter device used can be improved more reliably.

[0225] Similarly, when the antiresonant frequencies of the main modes in the variable excitation angle resonator are substantially identical in all the intersection regions J, it is possible to disperse the unnecessary waves outside the frequency band, and further suppress the unnecessary waves outside the frequency band. In addition, the resonance characteristics in the variable excitation angle resonator can be improved more reliably.

[0226] In this specification, the term "one frequency and the other frequency are substantially consistent" means that the absolute value of the difference between the two frequencies is less than 2% relative to the reference frequency. The reference frequency refers to the excitation angle θ. C_prop The frequency at 0°.

[0227] In the intersection region J of the excitation angle variable resonator, the absolute value of the difference between the highest resonant frequency and the lowest resonant frequency of the main mode is preferably 1% or less relative to the reference frequency. Alternatively, in the intersection region J of the excitation angle variable resonator, the absolute value of the difference between the highest anti-resonant frequency and the lowest anti-resonant frequency of the main mode is preferably 1% or less relative to the reference frequency. In this way, the resonance characteristics can be further reliably improved.

[0228] In the first embodiment, the resonance frequencies in the intersection region J of the first elastic wave resonator 1A, which is an excitation angle variable resonator, are substantially the same. Furthermore, the first elastic wave resonator 1A and the second elastic wave resonator 1B are split resonators that are split in series. In this specification, the split resonators that are split in series refer to a plurality of elastic wave resonators that are the same resonator parts, are connected in series, and the difference in resonance frequencies between them is 2% or less. On the other hand, in this specification, the split resonators that are split in parallel refer to a plurality of elastic wave resonators that are the same resonator parts, are connected in parallel, and the difference in resonance frequencies between them is 2% or less.

[0229] More specifically, when comparing the resonant frequency of the excitation angle-variable resonator with the resonant frequencies of other elastic wave resonators, the excitation angle θ in the intersection region J is C_prop The resonant frequency of the portion with a 0° angle can be compared with the resonant frequencies of other elastic wave resonators. C_prop The resonance frequency of the portion at 0° is set as the reference resonance frequency.

[0230] For example, in the first embodiment, the reference resonant frequency of the first elastic wave resonator 1A, which is an excitation angle variable resonator, and the resonant frequency of the second elastic wave resonator 1B, which is an elastic wave resonator that is not an excitation angle variable resonator, may be compared. The difference between the reference resonant frequency of the first elastic wave resonator 1A and the resonant frequency of the second elastic wave resonator 1B is 2% or less with respect to either the reference resonant frequency or the resonant frequency. Therefore, the first elastic wave resonator 1A and the second elastic wave resonator 1B are split resonators.

[0231] In the present invention, at least one of the plurality of elastic wave resonators of the elastic wave device may be an excitation angle variable resonator. The following describes a structure that is preferably established in at least one excitation angle variable resonator in the present invention. In the following description of the excitation angle variable resonator, the reference numerals of the structure of the first elastic wave resonator 1A may be used.

[0232] Preferably, the resonant frequencies or anti-resonant frequencies of the main mode in at least one excitation angle variable resonator are substantially consistent with each other in all intersection regions J. Thus, it is possible to disperse the useless waves outside the frequency band, and further suppress the useless waves outside the frequency band. Moreover, since the resonant frequencies or anti-resonant frequencies in the intersection region J are substantially consistent with each other, the main mode can be appropriately excited. Therefore, the resonance characteristics can be improved more reliably. Thus, the filter characteristics of the filter device used can be improved more reliably.

[0233] Preferably, at least two of the plurality of elastic wave resonators are excitation angle variable resonators, and these elastic wave resonators are split resonators that are split in series or in parallel. Specifically, in this case, the resonant frequencies are substantially consistent in each of the intersection regions J of the at least two excitation angle variable resonators. Furthermore, the following relationship holds true between the at least two excitation angle variable resonators. This relationship is a relationship in which the difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially consistent in the intersection region J is less than 2% relative to the reference resonant frequency of any of the two excitation angle variable resonators.

[0234] Thus, since the elastic wave resonator having the desired resonant frequency or anti-resonant frequency is divided in series or in parallel, the applied power can be dispersed. Therefore, the elastic wave resonator having the desired resonant frequency or anti-resonant frequency is less likely to be damaged.

[0235] However, the elastic wave resonators of the elastic wave device according to the present invention may be resonators that have a circuit structure equivalent to that of split resonators. For example, the following relationship may be established between at least two excitation angle variable resonators: the difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially the same in the intersection region J is greater than 2% relative to the reference resonant frequency of any one of the excitation angle variable resonators.

[0236] Preferably, at least one of the plurality of elastic wave resonators is not an excitation angle variable resonator, and at least one of the plurality of elastic wave resonators is an excitation angle variable resonator, and the elastic wave resonators are split resonators that are split in series or in parallel. Specifically, in this case, the resonant frequencies are substantially consistent in the intersection region J of the at least one excitation angle variable resonator. Furthermore, the following relationship holds true in the at least one excitation angle variable resonator and the at least one elastic wave resonator that is not an excitation angle variable resonator. The relationship is a relationship in which the difference between the reference resonant frequency of the excitation angle variable resonator whose resonant frequencies are substantially consistent in the intersection region J and the resonant frequency of the elastic wave resonator that is not an excitation angle variable resonator is 2% or less relative to either the reference resonant frequency or the resonant frequency.

[0237] In this case, since the elastic wave resonator having the desired resonant frequency or antiresonant frequency is divided in series or in parallel, the applied power can be dispersed. Therefore, the elastic wave resonator having the desired resonant frequency or antiresonant frequency is less likely to be damaged.

[0238] On the other hand, the following relationship may be satisfied in at least one excitation angle variable resonator and at least one elastic wave resonator that is not an excitation angle variable resonator: the difference between a reference resonant frequency of the excitation angle variable resonator and a resonant frequency of the elastic wave resonator that is not an excitation angle variable resonator, whose resonant frequencies are substantially identical in the intersection region J, is greater than 2% relative to either the reference resonant frequency or the resonant frequency.

[0239] In the first embodiment, in the first elastic wave resonator 1A, the duty ratio is adjusted according to the excitation angle θ C_prop Thus, the resonance frequency is made substantially uniform in all the intersection regions J. However, the present invention is not limited to this.

[0240] For example, it is preferable that, in at least one excitation angle variable resonator, at least one of the duty ratio, the electrode finger pitch, and the thickness of the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A is changed according to the excitation angle θ. C_prop Preferably, at least one of these parameters varies according to the excitation angle θ. C_prop The resonant frequency or the antiresonant frequency is substantially consistent in at least a portion of the intersection region J. It is more preferable that at least one of these parameters is changed according to the excitation angle θ. C_prop The resonant frequency or the antiresonant frequency is changed so as to be substantially the same in all the intersection regions J. This makes it possible to more reliably improve the resonance characteristics in the excitation angle variation type resonator.

[0241] Alternatively, when the thickness of the intermediate layer 5 in the piezoelectric substrate 2 or the like affects the frequency, the parameter may be adjusted in the intersection region J according to the excitation angle θ. C_prop When the dielectric film 8 is provided on the piezoelectric substrate 2 so as to cover the first IDT electrode 18A as in the first embodiment, the thickness of the dielectric film 8 may be varied in the intersection region J according to the excitation angle θ. C_prop The parameters of the first IDT electrode 18A or a plurality of parameters other than the first IDT electrode 18A may be changed in the intersection region J according to the excitation angle θ. C_prop In these cases, the resonant frequency or the anti-resonant frequency can be made substantially consistent in at least a part or the entirety of the intersection region J.

[0242] It is preferable that the excitation angle θ of the first IDT electrode 18A of at least one excitation angle variable resonator is C_prop In the same part, at least one of the electrode finger pitch and the duty cycle is constant. C_prop In the same part, both the electrode finger pitch and the duty ratio are constant. This makes it possible to more reliably improve the resonance characteristics of the excitation angle variable resonator.

[0243] When the shape of the plurality of electrode fingers of the first IDT electrode 18A in a plan view is an arc shape as in the first embodiment, it is preferable to have the following structure.

[0244] Preferably, the shapes of the plurality of first offset electrodes 12A and the plurality of second offset electrodes 13A in a plan view are arc-shaped. More preferably, the shapes of the plurality of first offset electrodes 12A and the plurality of second offset electrodes 13A in a plan view are shapes corresponding to arcs of a plurality of concentric circles. In this case, the centers of the circles including the arcs in the shapes of the plurality of offset electrodes coincide. More specifically, in the first embodiment, the centers of the circles including the arcs in the shapes of the plurality of electrode fingers and the plurality of offset electrodes coincide. Thus, leakage of the main mode from the intersection region J can be effectively suppressed.

[0245] Preferably, the shapes of the multiple reflector electrode fingers of the reflector 9A and the reflector 9B in a plan view are shapes corresponding to the arcs of the multiple concentric circles. More preferably, the centers of the circles including the arcs in the shapes of the multiple electrode fingers of the first IDT electrode 18A and the multiple reflector electrode fingers of each reflector are aligned. This can more reliably improve the resonance characteristics.

[0246] In addition, the shapes of the plurality of electrode fingers when viewed from above may also include the shapes of elliptical arcs. More specifically, in this case, the shapes of the plurality of electrode fingers when viewed from above include shapes corresponding to respective elliptical arcs in a plurality of ellipses whose centers of gravity are at the same position. The center of gravity referred to here refers to the center of the two foci of the ellipse. In this case, as in the first embodiment, it is possible to suppress useless waves outside the frequency band in the elastic wave device. In the case where the shape of the arc in the shape including the plurality of electrode fingers is an ellipse, the ellipticity coefficient α2 / α1 becomes other than 1.

[0247] When the shapes of the plurality of electrode fingers in a plan view include an elliptical arc, it is preferred that the shapes of the plurality of offset electrodes in a plan view also include an elliptical arc. In this case, it is preferred that the centers of gravity of the ellipses including the elliptical arcs in the shapes of the plurality of electrode fingers and the plurality of offset electrodes coincide with each other. Thus, leakage of the main mode from the intersection region J can be effectively suppressed.

[0248] When the shapes of the plurality of electrode fingers in a plan view include an elliptical arc, it is preferred that the shapes of the plurality of reflector electrode fingers of each reflector in a plan view also include an elliptical arc. In this case, it is preferred that the centers of gravity of the ellipses including the elliptical arcs in the shapes of the plurality of electrode fingers and the plurality of reflector electrode fingers are consistent. Thus, the resonance characteristics can be more reliably improved.

[0249] Examples of materials for the various components of the piezoelectric substrate 2 are shown below.

[0250] As Figure 4 The material of the support substrate 4 shown, for example, can also be aluminum nitride, lithium tantalate, lithium niobate, quartz and other piezoelectrics, alumina, sapphire, magnesium oxide, silicon nitride, silicon carbide, zirconium oxide, cordierite, mullite, steatite, forsterite, spinel, sialon and other ceramics, aluminum oxide, silicon oxynitride, DLC (diamond-like carbon), diamond and other dielectrics, or semiconductors such as silicon, or materials with the above materials as the main component. In addition, the above spinel contains an aluminum compound containing one or more elements selected from Mg, Fe, Zn, Mn and the like and oxygen. As examples of the above spinel, MgAl2O4, FeAl2O4, ZnAl2O4, and MnAl2O4 can be cited. It is preferred to use high-resistance silicon in the support substrate 4. The volume resistivity of the material of the support substrate 4 is preferably above 1000Ω·cm. In the first embodiment, high-resistance silicon is used as the material of the support substrate 4.

[0251] The first layer 5a of the intermediate layer 5 is a high-acoustic-velocity film. The high-acoustic-velocity film is a film with a relatively high-acoustic-velocity. More specifically, the acoustic velocity of the body wave propagating in the high-acoustic-velocity film is higher than the acoustic velocity of the elastic wave propagating in the piezoelectric layer 6. As the material of the high-acoustic-velocity film, i.e., the first layer 5a, for example, piezoelectrics such as aluminum nitride, lithium tantalate, lithium niobate, quartz, alumina, sapphire, magnesium oxide, silicon nitride, silicon carbide, zirconium oxide, cordierite, mullite, steatite, forsterite, spinel, ceramics such as sialon, dielectrics such as aluminum oxide, silicon oxynitride, DLC (diamond-like carbon), diamond, or semiconductors such as silicon, or materials with the above materials as the main component can also be used. In addition, the above spinel contains an aluminum compound containing one or more elements selected from Mg, Fe, Zn, Mn, etc. and oxygen. As examples of the above spinel, MgAl2O4, FeAl2O4, ZnAl2O4, and MnAl2O4 can be listed. In the first embodiment, silicon nitride is used as the material of the first layer 5 a.

[0252] The second layer 5b of the intermediate layer 5 is a low-acoustic-velocity film. The low-acoustic-velocity film is a film with a relatively low-acoustic-velocity. More specifically, the acoustic velocity of the body wave propagating in the low-acoustic-velocity film is lower than the acoustic velocity of the body wave propagating in the piezoelectric layer 6. As the material of the low-acoustic-velocity film, i.e., the second layer 5b, for example, dielectrics such as glass, silicon oxide, silicon oxynitride, lithium oxide, tantalum oxide, or compounds in which fluorine, carbon, or boron is added to silicon oxide, or materials containing the above materials as main components can be used. In the first embodiment, silicon oxide is used as the material of the second layer 5b.

[0253] As Figure 4 The material of the piezoelectric layer 6 shown may be, for example, lithium tantalate, lithium niobate, zinc oxide, aluminum nitride, quartz, or PZT (lead zirconate titanate). Lithium tantalate or lithium niobate is preferably used as the material of the piezoelectric layer 6. In the first embodiment, lithium tantalate is used as the material of the piezoelectric layer 6.

[0254] In the first embodiment, the first layer 5a as a high acoustic velocity film, the second layer 5b as a low acoustic velocity film, and the piezoelectric layer 6 are sequentially stacked on the piezoelectric substrate 2. This effectively confines the energy of the elastic wave to the piezoelectric layer 6 side.

[0255] As the material of the first IDT electrode 18A, the second IDT electrode 18B, and each reflector, for example, one or more metals selected from the group consisting of Ti, Mo, Ru, W, Al, Pt, Ir, Cu, Cr, and Sc may be used. The first IDT electrode 18A, the second IDT electrode 18B, and each reflector may include a single-layer metal film or a stacked metal film. In the first embodiment, Al is used as the material of the first IDT electrode 18A, the second IDT electrode 18B, and each reflector.

[0256] In this specification, the main component refers to a component that accounts for more than 50% by weight. The material of the main component may be in any state of single crystal, polycrystalline, or amorphous, or in a state of a mixture of these.

[0257] First to ninth modifications of the first embodiment are described below, in which only the structure of the first elastic wave resonator is different from that of the first embodiment. In the first to ninth modifications, as in the first embodiment, it is possible to suppress unnecessary waves outside the frequency band.

[0258] Figure 8 It is a schematic plan view of an elastic wave device according to a first modification of the first embodiment.

[0259] The first envelope E1C in the first elastic wave resonator 1C has a plurality of portions inclined relative to the propagation axis of the piezoelectric layer 6. Furthermore, the first envelope E1C has a plurality of bends V1. More specifically, the bends refer to portions where the direction in which the envelope extends changes. In this modification, the shape of the first envelope E1C is a wavy shape in which adjacent bends V1 are connected to each other by straight lines. Alternatively, the shape of the first envelope E1C may be a wavy shape in which adjacent bends V1 are connected to each other by curved lines.

[0260] Similarly, the second envelope E2C also has a plurality of portions inclined relative to the propagation axis. The second envelope E2C has a plurality of bends V2. The shape of the second envelope E2C is a wavy shape in which adjacent bends V2 are connected to each other by straight lines. In addition, the shape of the second envelope E2C may also be a wavy shape in which adjacent bends V2 are connected to each other by curved lines.

[0261] As described above, in this modification, both the first envelope E1C and the second envelope E2C have a plurality of bends. However, at least one of the first envelope E1C and the second envelope E2C may have at least one bend.

[0262] The first IDT electrode 18C has a plurality of segments with the electrode fingers passing through the bent portion V1 of the first envelope E1C as boundaries. The plurality of segments are arranged in the direction in which the propagation axis extends. Specifically, the first IDT electrode 18C has five segments.

[0263] Fig. 9 FIG. 1 is a schematic top view of a first elastic wave resonator in a first modification of the first embodiment. Fig. 9 , four segments are schematically shown.

[0264] The portion of the first electrode finger 16C that includes a portion located on the first envelope E1C and is adjacent to the front end of any second electrode finger 17C is the adjacent portion of the first electrode finger 16C. The portion of the second electrode finger 17C that includes a portion located on the second envelope E2C and is adjacent to the front end of any first electrode finger 16C is the adjacent portion of the second electrode finger 17C. The portion of the range of 1λ from the front end of the electrode finger along the direction in which the electrode finger extends is the front end of the electrode finger. The range of the adjacent portion is also the range of 1λ along the direction in which the electrode finger extends. The electrode finger pitch that serves as a reference for the range of the front end and the adjacent portion can also be set to, for example, the excitation angle θ C_prop The narrowest electrode finger pitch in the 0° portion.

[0265] In the first elastic wave resonator 1C as the excitation angle variable resonator of this modification, the shape of the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C when viewed from above is a shape whose curvature changes gently. Specifically, the shape of the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C when viewed from above is a shape that can be approximated as an arc. In the intersection region J, the excitation direction of the elastic wave and the excitation angle θ are C_prop no the same.

[0266] However, for example, the shapes of the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C when viewed from above may be shapes that can be approximated by an elliptical arc. In addition, the shapes of the electrode fingers when viewed from above may not necessarily be shapes that can be approximated by a circular arc or an elliptical arc. In this case, for example, the shapes of the electrode fingers when viewed from above may be shapes that cannot be approximated by a circular arc or an elliptical arc, which are parabolic shapes.

[0267] The shapes of all the electrode fingers in the first IDT electrode 18C when viewed from above are preferably shapes of curves that are different from each other. This example is specifically shown as three examples. As a first example, it is preferred that the curvatures are different from each other between the front end portions of all the first electrode fingers 16C and all the second electrode fingers 17C located on the first envelope E1C side, between the adjacent portions, or between the front end portions and the adjacent portions. More specifically, it is preferred that the curvatures are different from each other between the front end portions of all the second electrode fingers 17C, between the adjacent portions of all the first electrode fingers 16C, and between the front end portions of all the second electrode fingers 17C and the adjacent portions of all the first electrode fingers 16C.

[0268] As a second example, it is preferred that the curvatures are different between the tip portions of all the first electrode fingers 16C and all the second electrode fingers 17C located on the second envelope E2C side, between adjacent portions, or between the tip portions and adjacent portions. More specifically, it is preferred that the curvatures are different between the tip portions of all the first electrode fingers 16C, between adjacent portions of all the second electrode fingers 17C, and between the tip portions of all the first electrode fingers 16C and adjacent portions of all the second electrode fingers 17C.

[0269] As a third example, it is preferable that all the first electrode fingers 16C and all the second electrode fingers 17C located at the excitation angle θ C_prop The portions at 0° have different curvatures. As described above, the shapes of all electrode fingers in the first IDT electrode 18C in a plan view are different curved lines, which can more reliably and effectively suppress unnecessary waves.

[0270] In this variation, all of the above three examples are satisfied. However, it is sufficient that, in at least one group of electrode fingers among the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C, the curvatures are different between the front end portions located on the first envelope E1C side, between the adjacent portions, or between the front end portion and the adjacent portion.

[0271] Similar to the first embodiment, in this variation, the intersection region J is composed of a curved region. In the curved region, the shape of the plurality of electrode fingers when viewed from above is a curve that is not a circular arc or an elliptical arc. The shape of the plurality of electrode fingers when viewed from above is a shape that can be approximated as a circular arc. In other words, the shape of the plurality of electrode fingers when viewed from above is a state that appears to be approximately a circular arc. Moreover, the shape of the plurality of electrode fingers when viewed from above is a shape of a curve that is different from one another. Therefore, Fig.10 The relationship shown holds.

[0272] Fig.10 This is a schematic plan view showing a circle including an arc when the shape of the electrode fingers of the first IDT electrode in the first modification of the first embodiment in a plan view is approximated as an arc.

[0273] exist Fig.10 In FIG. 1 , two circles R1 and R2 are shown by dotted lines. The circles R1 and R2 are circles containing arcs when the shapes of two different electrode fingers in a plan view are approximated as arcs. The position of the center O1 of the circle R1 and the position of the center O2 of the circle R2 are different from each other.

[0274] In the curved area, it is preferred that the positions of the centers of the circles containing the arcs when the shapes of all the first electrode fingers 16C and all the second electrode fingers 17C when viewed from above are approximated as arcs are different from each other. In this case, as described above, the shapes of all the electrode fingers in the first IDT electrode 18C when viewed from above are the shapes of curves that are different from each other. Thus, it is possible to suppress useless waves more reliably and effectively. However, in the curved area, it is sufficient that the positions of the centers of the circles containing the arcs when the shapes of at least one group of electrode fingers among the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C when viewed from above are approximated as arcs are different from each other.

[0275] In addition, in the curved region, the shapes of the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C in a plan view may be approximated as elliptical arcs. In this case, in the curved region, it is preferred that the positions of the centroids of the ellipses containing the elliptical arcs when the shapes of all the first electrode fingers 16C and all the second electrode fingers 17C in a plan view are approximated as elliptical arcs are different from each other. However, in the curved region, it is sufficient that the positions of the centroids of the ellipses containing the elliptical arcs when the shapes of at least one group of electrode fingers among the plurality of first electrode fingers 16C and the plurality of second electrode fingers 17C in a plan view are approximated as elliptical arcs are different from each other.

[0276] return Figure 8 , the excitation angle θ of the portion located at the end of the first envelope E1C or the bent portion V1 is C_prop Let the excitation angle θ on the first envelope line be C_AP1_m m is a natural number. The excitation angle θ on the first envelope line C_AP1_m The excitation angle θ can be defined for the end of the first envelope E1C or each bend V1. Specifically, the excitation angle θ on the first envelope is sequentially increased from the end and bend V1 on the inner side of the first IDT electrode 18C. C_AP1_m m in is 1, 2, 3, ... In this way, the excitation angle θ on the first envelope line located on the inner side is C_AP1_m , the smaller the value of m is. For example, the excitation angle θ of the part of the above end located on the inner side is C_prop is the excitation angle θ on the first envelope line C_AP1_1 The excitation angle θ at the innermost bend V1 C_prop is the excitation angle θ on the first envelope line C_AP1_2 .

[0277] Similarly, the excitation angle θ of the portion located at the end of the second envelope E2C or the bent portion V2 is set to C_prop Let the excitation angle θ on the second envelope be C_AP2_m The more the second envelope is located on the inner side, the smaller the excitation angle θ is. C_AP2_m , the smaller the value of m.

[0278] The shapes of the reflectors 9E and 9F are set to correspond to the shape of the first IDT electrode 18C. The shapes of the reflector electrode fingers of the reflectors 9E and 9F in a plan view are curved.

[0279] Fig.11 It is a schematic plan view of an elastic wave device according to a second modification of the first embodiment. Fig.12 FIG. 1 is a schematic plan view of a first elastic wave resonator in a second modification of the first embodiment. Fig.12 , three segments are schematically shown.

[0280] like Fig.11 As shown in FIG. 1 , in the first elastic wave resonator 1D, the shape of the plurality of electrode fingers in a plan view is not a curved shape. Specifically, Fig.12 As shown in FIG. 1 , in the first IDT electrode 18D, the plurality of first electrode fingers 16D and the plurality of second electrode fingers 17D are bent at a plurality of nodes when viewed from above. More specifically, the plurality of first electrode fingers 16D and the plurality of second electrode fingers 17D are connected to each other in straight lines at their respective nodes when viewed from above. In addition, in this modified example, each electrode finger is bent as a whole so as to be bent toward the Fig.12 The shape of each electrode finger in a plan view can be approximated to a circular arc, an elliptical arc, or a parabola.

[0281] Fig.13 FIG. 2 is a schematic top view showing the parallel region and the non-parallel region in the second modification of the first embodiment. Fig.13 In the figure, each region is shown with hatching. In addition, the parallel region described later and the region obtained by extending the parallel region are hatched with the same hatching. In the non-parallel region described later and the region obtained by extending the non-parallel region are hatched with the same hatching.

[0282] The intersection region J has a plurality of parallel regions A and a plurality of non-parallel regions B. Specifically, the so-called parallel region A refers to a region where a plurality of first electrode fingers 16D and a plurality of second electrode fingers 17D extend in parallel. In the present specification, the so-called parallel extension of a plurality of electrode fingers does not only include strictly parallel extension, but also includes substantially parallel extension. Specifically, for example, when the angle formed by the direction in which one electrode finger extends and the direction in which another electrode finger extends is within a range of ±1°, the electrode fingers are also considered to extend parallel to each other. On the other hand, the so-called non-parallel region B refers to a region where the directions in which a plurality of first electrode fingers 16D and a plurality of second electrode fingers 17D extend intersect with each other. In addition, the intersection region J only needs to include at least two parallel regions A and at least one non-parallel region B.

[0283] In the first IDT electrode 18D, a portion of the plurality of parallel regions A and a portion of the plurality of non-parallel regions B respectively include a portion of all the first electrode fingers 16D and a portion of all the second electrode fingers 17D. The parallel regions A other than the above include a portion of the plurality of first electrode fingers 16D and a portion of the plurality of second electrode fingers 17D. The remaining plurality of electrode fingers are not included in the parallel region A. The same is true for the non-parallel regions B other than the above. However, it is also possible that all the parallel regions A and all the non-parallel regions B respectively include a portion of all the electrode fingers.

[0284] The parallel regions A and the non-parallel regions B are arranged alternately. The plurality of first electrode fingers 16D and the second electrode fingers 17D extend linearly in the plurality of parallel regions A and the non-parallel regions B, respectively, and are bent at the boundaries between the parallel regions A and the non-parallel regions B.

[0285] In the parallel regions A, the directions in which the electrode fingers extend are different from each other. Therefore, in the intersection region J, the excitation direction and the excitation angle θ of the elastic wave are different. C_prop no the same.

[0286] The shapes of the multiple reflector electrode fingers of the reflectors 9G and 9H in a plan view are bent at multiple nodes, similar to the electrode fingers of the first IDT electrode 18D. Specifically, the multiple reflector electrode fingers extend linearly in the region where the parallel region A is extended and the region where the non-parallel region B is extended. Furthermore, the multiple reflector electrode fingers are bent at the boundary between the region where the parallel region A is extended and the region where the non-parallel region B is extended. Thus, the resonance characteristics can be more reliably improved.

[0287] In this modification, the shapes of some of the plurality of first offset electrodes 12D and some of the plurality of second offset electrodes 13D in a plan view are curved shapes connected to each other by straight lines. The shapes of the remaining offset electrodes in a plan view are straight lines. Alternatively, the shapes of all the first offset electrodes 12D and all the second offset electrodes 13D in a plan view may be curved shapes or straight lines.

[0288] Fig.14 It is a schematic plan view of a first elastic wave resonator in a third modification of the first embodiment.

[0289] In this variation, the plurality of electrode fingers of the first IDT electrode 18E include a linear portion. Specifically, the intersection region of the first IDT electrode 18E includes a first region W1, a second region W2, and a third region W3. The first region W1, the second region W2, and the third region W3 are arranged in directions in which the first bus bar 14A and the second bus bar 15A are opposed to each other. More specifically, the first region W1 and the second region W2 are opposed to each other with the third region W3 sandwiched therebetween. The first region W1 is located on the first bus bar 14A side. The second region W2 is located on the second bus bar 15A side. In the third region W3, the shape of the plurality of electrode fingers when viewed from above is a linear shape. In the intersection region, the excitation direction and the excitation angle θ of the elastic wave are C_prop no the same.

[0290] On the other hand, in the first region W1 and the second region W2, the shape of the plurality of electrode fingers when viewed from above is an elliptical arc shape. In this way, each electrode finger includes a portion having a different curvature of the shape when viewed from above. In addition, in the first region W1 and the second region W2, the shape of the plurality of electrode fingers when viewed from above may also be an arc shape. Alternatively, in the first region W1 and the second region W2, the shape of the plurality of electrode fingers when viewed from above may also be a curved shape that can be approximated as an arc or an elliptical arc.

[0291] In this modification, in all third regions W3, the direction in which the propagation axis of the piezoelectric layer 6 extends is orthogonal to the direction in which the plurality of electrode fingers extend. In the third region W3, the excitation angle θ C_prop is 0°. Therefore, the third region W3 is a region that is stable relative to the propagation axis. By having the third region W3 in the intersection region, it is possible to suppress the degradation of the relative bandwidth. When the resonant frequency is fr and the antiresonant frequency is fa, the relative bandwidth is represented by |fr-fa| / fr×100[%]. In addition, the excitation angle θ in the third region W3 is C_prop Not limited to 0°.

[0292] Fig.15 It is a schematic plan view of a first elastic wave resonator in a fourth modification of the first embodiment.

[0293] In the first elastic wave resonator of this modification, the intersection region has a plurality of curved regions. Specifically, the plurality of curved regions are a first curved region K1 and a second curved region K2. The first curved region K1 includes a first envelope E1. The second curved region K2 includes a second envelope E2. The boundary between the first curved region K1 and the second curved region K2 is a straight line.

[0294] In this modification, in each curved region, the shapes of the first electrode fingers 16F and the second electrode fingers 17F when viewed from above are each a single arc shape. The shapes of the electrode fingers when viewed from above are each a shape connecting two arcs. In each electrode finger, at the boundary between the first curved region K1 and the second curved region K2, the two curved shapes are inverted.

[0295] Specifically, in the first curve region K1, the plurality of electrode fingers are bent so as to Fig.15 The arcs in the shapes of the portions of the plurality of electrode fingers located in the first curve region K1 are respective arcs in the plurality of concentric circles. Therefore, the centers of the circles including the arcs in the shapes of the plurality of electrode fingers in the first curve region K1 coincide with each other.

[0296] On the other hand, in the second curve region K2, the plurality of electrode fingers are bent so as to Fig.15 The arcs in the shapes of the portions of the plurality of electrode fingers located in the second curve region K2 are respective arcs in the plurality of concentric circles. Therefore, the centers of the circles including the arcs in the shapes of the plurality of electrode fingers in the second curve region K2 coincide with each other.

[0297] The center of the circle including the arcs in the shape of the plurality of electrode fingers in the first curved region K1 and the center of the circle including the arcs in the shape of the plurality of electrode fingers in the second curved region K2 face each other with the first IDT electrode 18F interposed therebetween.

[0298] As described above, the shapes of the plurality of first electrode fingers 16F and the plurality of second electrode fingers 17F in a plan view include at least two curved portions in which the bending directions of the first electrode fingers 16F and the second electrode fingers 17F are different in the intersection region. In this case, the excitation direction and the excitation angle θ of the elastic wave in the intersection region are C_prop no the same.

[0299] In addition, in each curved region, the shape of the plurality of electrode fingers in a plan view may be a single elliptical arc. Alternatively, in each curved region, the shape of the plurality of electrode fingers in a plan view may be a curved shape that can be approximated by a single circular arc or elliptical arc.

[0300] Similar to the plurality of electrode fingers of the first IDT electrode 18F, the shapes of the plurality of reflector electrode fingers of each reflector when viewed from above are shapes formed by connecting two circular arcs. Alternatively, the shapes of the reflector electrode fingers when viewed from above may be shapes formed by connecting two elliptical arcs. Alternatively, the shapes of the reflector electrode fingers when viewed from above may be shapes formed by connecting two curves that can be approximated as circular arcs or elliptical arcs.

[0301] In this modification, both the first envelope E1 and the second envelope E2 are linear and extend in parallel. The first envelope E1 and the second envelope E2 extend obliquely with respect to the propagation axis of the piezoelectric layer 6 .

[0302] Fig.16 It is a schematic plan view of a first elastic wave resonator in a fifth modification of the first embodiment.

[0303] The intersection region J of the first IDT electrode 18G has a central region F and a pair of edge regions. The pair of edge regions are specifically a first edge region H1 and a second edge region H2. The first edge region H1 includes a first envelope E1 as an end edge. The second edge region H2 includes a second envelope E2 as an end edge. The first edge region H1 and the second edge region H2 are opposed to each other with the central region F sandwiched therebetween. It is to be noted that each intersection region of other embodiments and modified examples also has a first edge region, a second edge region, and a central region.

[0304] In addition, the first edge region H1 is a region where the front end of the second electrode finger 17G and the adjacent portion of the first electrode finger 16G are located. That is, if the second electrode finger 17G is used as a reference, the first edge region H1 is a region with a range of about 1λ from the front end of the second electrode finger 17G along the direction in which the electrode finger extends. Similarly, if the first electrode finger 16G is used as a reference, the second edge region H2 is a region with a range of about 1λ from the front end of the first electrode finger 16G along the direction in which the electrode finger extends.

[0305] Each electrode finger of the first IDT electrode 18G has a wide portion in the first edge region H1 and the second edge region H2 . The width of the electrode finger in the wide portion is wider than the width of the electrode finger in the central region F.

[0306] Specifically, the first electrode finger 16G has a wide portion 16a in the first edge region H1. The second electrode finger 17G also has a wide portion 17a in the first edge region H1. On the other hand, the first electrode finger 16G has a wide portion 16b in the second edge region H2. The second electrode finger 17G also has a wide portion 17b in the second edge region H2. As a result, the sound velocity in the first edge region H1 and the second edge region H2 is lower than the sound velocity in the central region F. As a result, a low sound velocity region is formed in the first edge region H1 and the second edge region H2. The so-called low sound velocity region refers to a region where the sound velocity is lower than the sound velocity in the central region F.

[0307] In this modified example, a central region F and a pair of low sound velocity regions are sequentially arranged from the inside to the outside in the direction in which the first bus bar 14A and the second bus bar 15A are opposed. Thus, a piston mode is established. Thus, the transverse mode can be suppressed. Moreover, the energy of the main mode can be effectively confined in the central side of the intersection region J, and the characteristics of the main mode can be improved.

[0308] The structure of the first IDT electrode 18G is the same as that of the first embodiment except for the first edge region H1 and the second edge region H2. Therefore, in the intersection region J, the excitation direction and the excitation angle θ of the elastic wave are C_prop no the same.

[0309] In addition, at least one electrode finger may have a wide portion in at least one of the first edge region H1 and the second edge region H2. However, it is preferred that a plurality of electrode fingers have a wide portion in at least one of the first edge region H1 and the second edge region H2, and it is more preferred that all electrode fingers have a wide portion. Furthermore, it is more preferred that a plurality of electrode fingers have a wide portion in both the first edge region H1 and the second edge region H2, and it is further preferred that all electrode fingers have a wide portion. Thus, the piston mode can be established more reliably.

[0310] The shape of the plurality of electrode fingers of the 0th IDT electrode 18G in a plan view is an arc shape. However, the structure in which the low acoustic velocity region is provided in the first edge region H1 or the second edge region H2 in the elastic wave resonator can also be adopted in other structures of the present invention in which the shape of the electrode fingers is different from that of this modification.

[0311] In the first IDT electrode 18G, the width of each electrode finger is widened throughout the entire edge region. The shape of each wide portion when viewed from above is a quadrilateral. However, each electrode finger may be widened in at least a portion of each edge region. The shape of each wide portion when viewed from above is not limited to a quadrilateral. Each reflector electrode finger of each reflector may also be widened in a portion located on an extension line of the first edge region H1 and a portion located on an extension line of the second edge region H2.

[0312] On the other hand, Fig.17 In the sixth variation shown, a plurality of mass addition films 19 are provided, thereby forming a low sound velocity region in the first edge region H1 and the second edge region H2. Specifically, in the first edge region H1, a mass addition film 19 is provided on each first electrode finger 16A and each second electrode finger 17A. The same is true in the second edge region H2. In addition, the structure of the first TDT electrode 18A is the same as that of the first embodiment.

[0313] In this modification, the mass-added film 19 is provided only on one electrode finger. In this case, a suitable metal or dielectric can be used as the material of the mass-added film 19. However, the mass-added film 19 can also be provided across a plurality of electrode fingers. In this case, a suitable dielectric can be used as the material of the mass-added film 19.

[0314] The mass addition film 19 may be stacked with at least one of the plurality of electrode fingers in at least one of the first edge region H1 and the second edge region H2. Specifically, the mass addition film 19 may be arranged in at least one of the first edge region H1 and the second edge region H2 so as to overlap with at least one of the plurality of first electrode fingers 16A and the plurality of second electrode fingers 17A in a plan view. In this case, at least a portion of at least one of the first edge region H1 and the second edge region H2 constitutes a low sound velocity region.

[0315] Preferably, in at least one of the first edge region H1 and the second edge region H2, a plurality of electrode fingers are stacked with the mass addition film 19, and more preferably, all of the electrode fingers are stacked with the mass addition film 19. Alternatively, more preferably, in both the first edge region H1 and the second edge region H2, a plurality of electrode fingers are stacked with the mass addition film 19. Thus, the piston mode can be established more reliably. Further preferably, in the edge regions of both sides, all of the electrode fingers are stacked with the mass addition film 19. In this case, the entire edge region of both sides constitutes a low sound velocity region. Thus, the piston mode can be established more reliably.

[0316] In the portion where the electrode fingers and the mass-added film 19 are stacked, the piezoelectric substrate 2, the electrode fingers, and the mass-added film 19 are stacked in this order. However, it is also possible that in the portion where the electrode fingers and the mass-added film 19 are stacked, the piezoelectric substrate 2, the mass-added film 19, and the electrode fingers are stacked in this order. That is, the mass-added film 19 may also be provided between the piezoelectric substrate 2 and the electrode fingers. It is also possible that the portion of the reflector electrode fingers of each reflector located on the extension line of the first edge region H1 and the portion located on the extension line of the second edge region H2 are also stacked with the mass-added film 19.

[0317] The material of the mass additional film 19 can also be the same metal as that used for each electrode finger. Fig.18 (a) and Fig.18 The structure of the seventh variant shown in (b) is as follows. Fig.18 As shown in (a), in the first IDT electrode 18H, the thickness of the first electrode finger 16H in the first edge region H1 and the second edge region H2 is thicker than the thickness of the first electrode finger 16H in the central region F. Fig.18As shown in (b), the thickness of the second electrode finger 17H in the first edge region H1 and the second edge region H2 is thicker than the thickness of the second electrode finger 17H in the central region F. Thus, low acoustic velocity regions are formed in the first edge region H1 and the second edge region H2.

[0318] In addition, Fig.18 In (a), a cross section of the first electrode finger 16H along the direction in which the first electrode finger 16H extends is schematically shown. Fig.18 (b) schematically shows a cross section of the second electrode finger 17H along the direction in which the second electrode finger 17H extends. The structure of the first IDT electrode 18H is the same as that of the first embodiment except for the first edge region H1 and the second edge region H2.

[0319] The thickness of at least one electrode finger in at least one of the first edge region H1 and the second edge region H2 may be thicker than the thickness of the electrode finger in the central region F. However, it is preferred that the thickness of a plurality of electrode fingers in at least one of the first edge region H1 and the second edge region H2 is thicker than the thickness of the electrode finger in the central region F. It is more preferred that the thickness of all electrode fingers in at least one of the first edge region H1 and the second edge region H2 is thicker than the thickness of the electrode finger in the central region F.

[0320] Furthermore, it is more preferable that the thickness of the plurality of electrode fingers in both the first edge region H1 and the second edge region H2 is thicker than the thickness of the electrode fingers in the central region F. It is further preferable that the thickness of all electrode fingers in both the first edge region H1 and the second edge region H2 is thicker than the thickness of the electrode fingers in the central region F. Thus, the piston mode can be established more reliably.

[0321] In this modification, the thickness of each electrode finger is thicker throughout the entire edge region. However, each electrode finger may be thicker in at least a portion of each edge region. Alternatively, each reflector electrode finger of each reflector may be thicker in a portion located on an extension line of the first edge region H1 and a portion located on an extension line of the second edge region H2. The low sound velocity region may be provided by at least any one of the structures in the fifth to seventh modifications. For example, the low sound velocity region may be provided by a plurality of structures in the fifth to seventh modifications.

[0322] Fig.19 It is a schematic plan view of a first elastic wave resonator in an eighth modification of the first embodiment.

[0323] The structure of the first IDT electrode 18I in this modification is the same as that of the first IDT electrode 18G in the fifth modification except for the first offset electrode 12I and the second offset electrode 13I. Therefore, in the intersection region J, the excitation direction and excitation angle θ of the elastic wave are C_prop The width of the tip portion of the first offset electrode 12I in this modification is wider than the width of the other portion of the first offset electrode 12I. The width of the tip portion of the second offset electrode 13I is wider than the width of the other portion of the second offset electrode 13I.

[0324] Fig. 20 It is a schematic plan view of an elastic wave device according to a ninth modification of the first embodiment.

[0325] In the first IDT electrode 18J of the first elastic wave resonator 1J, the first envelope E1 and the second envelope E2 extend in parallel with the direction in which the propagation axis of the piezoelectric layer 6 extends. In addition, the shape of the first IDT electrode 18J when viewed from above is an arc shape as in the first embodiment. Therefore, in the intersection region, the excitation direction and the excitation angle θ of the elastic wave are C_prop no the same.

[0326] In addition, the direction in which the first envelope E1 extends may be parallel to the direction in which the second envelope E2 extends and may intersect with the direction in which the propagation axis extends.

[0327] In addition, the shape of the plurality of electrode fingers when viewed from above may be an elliptical arc. Alternatively, the shape of the plurality of electrode fingers when viewed from above may be a curved shape that can be approximated to a circular arc or an elliptical arc, or a parabola that cannot be approximated to a circular arc or an elliptical arc. On the other hand, the shape of the plurality of electrode fingers when viewed from above may be a shape that is bent at a plurality of sections, as in the second variant.

[0328] Fig.21 It is a schematic plan view of an elastic wave device according to a second embodiment.

[0329] The present embodiment is different from the first embodiment in the structure of the second elastic wave resonator 21B. On the other hand, the first elastic wave resonator 1D is configured in the same manner as the second variation of the first embodiment. Except for the above-mentioned aspects, the elastic wave device 21 of the present embodiment has the same structure as the first embodiment. In addition, the second elastic wave resonator 21B is an elastic wave resonator that is not an excitation angle variable resonator.

[0330] In the second elastic wave resonator 21B, the third envelope E3 and the fourth envelope E4 of the second IDT electrode 28B extend obliquely with respect to the propagation axis of the piezoelectric layer 6. In addition, the third envelope E3 and the fourth envelope E4 are straight lines, and the third envelope E3 and the fourth envelope E4 extend in parallel. In this way, the second IDT electrode 28B is an inclined IDT electrode. In the second elastic wave resonator 21B, the transverse mode can be suppressed.

[0331] Furthermore, the elastic wave device 21 of the present embodiment includes the first elastic wave resonator 1D as an excitation angle variable resonator, similarly to the second modification of the first embodiment. Therefore, it is possible to suppress unnecessary out-of-band waves.

[0332] The first elastic wave resonator 1D of the elastic wave device 21 may have a structure of the excitation angle-variable resonator according to the present invention other than the second modification of the first embodiment.

[0333] Fig. 22 It is a schematic plan view of an elastic wave device according to a third embodiment.

[0334] This embodiment differs from the first embodiment in that both first elastic wave resonator 31A and second elastic wave resonator 41C are excitation angle-variable resonators. Elastic wave device 31 of this embodiment has the same structure as elastic wave device 1 of the first embodiment except for the above-described features.

[0335] First elastic wave resonator 31A has the same structure as first elastic wave resonator 1A in the first embodiment. Second elastic wave resonator 41C has the same structure as first elastic wave resonator 1C in the first variation of the first embodiment. In the present embodiment, first elastic wave resonator 31A and second elastic wave resonator 41C are excitation angle variation resonators, and the structures in the intersection regions are different from each other.

[0336] In the first elastic wave resonator 31A, a plurality of electrode fingers are bent so as to face Fig. 22 On the other hand, in the second elastic wave resonator 41C, the plurality of electrode fingers are bent so as to protrude to the right. Fig. 22 The left direction is protruding.

[0337] In the elastic wave device 31 having the structure of this embodiment and Figure 6 The phase characteristics of the elastic wave devices of the comparative examples shown in FIG. 1 are compared. In addition, the results of the first embodiment are also shown. The design parameters of the first embodiment and the comparative example involved in this comparison are as follows: Figure 7The comparison shown is the same as the first embodiment and the comparative example. The design parameters of the elastic wave resonator having the structure of the first elastic wave resonator 31A in the present embodiment are as follows.

[0338] Support substrate: Material...Si, Surface orientation...(111), Euler angles ( ,θ,ψ) in which ψ...73°

[0339] Intermediate layer 1: Material...SiN, thickness...0.15λ

[0340] Intermediate layer 2: Material...SiO2, thickness...0.15λ

[0341] Piezoelectric layer: Material... Rotated Y-cut 55°X-propagated LiTaO3, thickness... 0.2λ

[0342] 1st IDT electrode: Material...Al, Thickness...0.05λ

[0343] Dielectric film: Material...SiO2, Thickness...0.015λ

[0344] Crossing angle θ C1_AP : 5°

[0345] Crossing angle θ C2_AP : -5°

[0346] Wavelength λ: at excitation angle θ C_prop The 0° portion is 2 μm

[0347] Number of electrode finger pairs of the first IDT electrode: 80 pairs

[0348] Duty cycle: At the excitation angle θ C_prop The part with a value of 0° is 0.5, and the absolute value of the excitation angle |θ C_prop |The larger it is, the smaller the duty cycle is.

[0349] Gap length: 0.135λ

[0350] Length of offset electrode: 3.5λ

[0351] Each reflector: Number of pairs of reflector electrode fingers...20 pairs

[0352] The design parameters of the elastic wave resonator having the structure of second elastic wave resonator 41C in the present embodiment are as follows.

[0353] Support substrate: Material...Si, Surface orientation...(111), Euler angles ( ,θ,ψ) in which ψ...73°

[0354] Intermediate layer 1: Material...SiN, thickness...0.15λ

[0355] Intermediate layer 2: Material...SiO2, thickness...0.15λ

[0356] Piezoelectric layer: Material... Rotated Y-cut 55°X-propagated LiTaO3, thickness... 0.2λ

[0357] 1st IDT electrode: Material...Al, Thickness...0.05λ

[0358] Dielectric film: Material...SiO2, Thickness...0.015λ

[0359] Wavelength λ: at excitation angle θ C_prop The 0° portion is 2 μm

[0360] Number of electrode finger pairs of the first IDT electrode: 100 pairs

[0361] Duty cycle: At the excitation angle θ C_prop The part with 0° is 0.5

[0362] Gap length: 0.135λ

[0363] Length of offset electrode: 3.5λ

[0364] The distance between the first envelope and the second envelope in the direction perpendicular to the propagation axis: 25λ

[0365] 1st envelope: Absolute value of the inclination angle with respect to the propagation axis: 20°, Number of pairs of electrode fingers between bends: 20 pairs

[0366] Second envelope: Absolute value of the inclination angle with respect to the propagation axis: 20°, Number of pairs of electrode fingers between bends: 20 pairs

[0367] Excitation angle on the first envelope line: θ C_AP1_1 =12°,θ C_AP1_2 =8°,θ C_AP1_3 =16°,θ C_AP1_4 =10°,θ C_AP1_5 =16°,θ C_AP1_6 =9°

[0368] Excitation angle on the second envelope line: θ C_AP2_1 =9°,θ C_AP2_2 =15°,θ C_AP2_3 =8°,θ C_AP2_4 =15.5°,θ C_AP2_5 =10°,θ C_AP2_6 =16°

[0369] Each reflector: Number of pairs of reflector electrode fingers...20 pairs

[0370] Fig.23 It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment, the third embodiment, and the comparative example.

[0371] like Fig.23 As shown, it can be seen that in the first embodiment, the Rayleigh wave, which is an unnecessary wave, can be suppressed compared to the comparative example. Furthermore, it can be seen that in the third embodiment, the Rayleigh wave can be further suppressed.

[0372] This is because, in the third embodiment, both the first elastic wave resonator 31A and the second elastic wave resonator 41C are excitation angle variable resonators. In the elastic wave device 31, it is possible to suppress unnecessary waves outside the frequency band in all elastic wave resonators. Thus, the elastic wave device 31 as a whole can further suppress unnecessary waves outside the frequency band. Furthermore, the transverse mode can be suppressed in both the first elastic wave resonator 31A and the second elastic wave resonator 41C. Therefore, the transverse mode can also be effectively suppressed as a whole elastic wave device.

[0373] As described above, in the elastic wave device according to the present invention, the elastic wave resonators may be connected in parallel with each other. Fig.24 In the first modification of the third embodiment shown, the first elastic wave resonator 31A and the second elastic wave resonator 41C are connected in parallel to each other. In this modification, as in the third embodiment, it is possible to suppress unnecessary waves outside the frequency band.

[0374] When the elastic wave device includes a plurality of excitation angle variable resonators, the combination of the structures of the excitation angle variable resonators is not limited to the combination of the third embodiment. The second and third variations of the third embodiment are shown below, in which only the combination of the plurality of excitation angle variable resonators is different from that of the third embodiment. In the second and third variations, it is possible to suppress unnecessary waves outside the frequency band in the same manner as in the third embodiment.

[0375] exist Fig.25 In the second modification shown in FIG. 1 , a second elastic wave resonator 31D has the same structure as the first elastic wave resonator 1D in the second modification of the first embodiment. In the second elastic wave resonator 31D, a plurality of electrode fingers are bent so as to face the first elastic wave resonator 1D. Fig.25 The left side of the first elastic wave resonator 31A is configured similarly to that of the third embodiment.

[0376] In the elastic wave device having the structure of this modification example and Figure 6The phase characteristics of the elastic wave devices of the comparative examples shown in FIG. 1 are compared. In addition, the results of the first embodiment are also shown. The design parameters of the first embodiment and the comparative example involved in this comparison are as follows: Fig.23 The comparison shown in FIG. 1 is the same as that of the first embodiment and the comparative example. Furthermore, the design parameters of the elastic wave resonator having the structure of the first elastic wave resonator 31A in this modification are the same as those of the first embodiment and the comparative example. Fig.23 The same is true for the third embodiment according to the comparison shown in the figure. The design parameters of the elastic wave resonator having the structure of the second elastic wave resonator 31D in this modification are as follows.

[0377] Support substrate: Material...Si, Surface orientation...(111), Euler angles ( ,θ,ψ) in which ψ...73°

[0378] Intermediate layer 1: Material...SiN, thickness...0.15λ

[0379] Intermediate layer 2: Material...SiO2, thickness...0.15λ

[0380] Piezoelectric layer: Material... Rotated Y-cut 55°X-propagated LiTaO3, thickness... 0.2λ

[0381] 1st IDT electrode: Material...Al, Thickness...0.05λ

[0382] Dielectric film: Material...SiO2, Thickness...0.015λ

[0383] Wavelength λ: at excitation angle θ C_prop The 0° portion is 2 μm

[0384] Number of electrode finger pairs of the first IDT electrode: 100 pairs

[0385] Duty cycle: At the excitation angle θ C_prop The part with 0° is 0.5

[0386] Gap length: 0.135λ

[0387] Length of offset electrode: 3.5λ

[0388] The distance between the first envelope and the second envelope in the direction perpendicular to the propagation axis: 25λ

[0389] 1st envelope: Absolute value of the inclination angle with respect to the propagation axis: 20°, Number of pairs of electrode fingers between bends: 20 pairs

[0390] Second envelope: Absolute value of the inclination angle with respect to the propagation axis: 20°, Number of pairs of electrode fingers between bends: 20 pairs

[0391] Excitation angle on the first envelope line: θ C_AP1_1 =6.2°,θ C_AP1_2 =6.3°,θ C_AP1_3 =6.3°,θ C_AP1_4 =4.4°,θ C_AP1_5 =12°,θ C_AP1_6 =8.4°

[0392] Excitation angle on the second envelope line: θ C_AP2_1 =14.3°,θ C_AP2_2 =8.8°,θ C_AP2_3 =12.5°,θ C_AP2_4 =6°,θ C_AP2_5 =4.2°,θ C_AP2_6 =12.3°

[0393] Each reflector: Number of pairs of reflector electrode fingers...20 pairs

[0394] Fig.26 It is a diagram showing phase characteristics near the frequency at which unnecessary waves are generated in the first embodiment, the second modification of the third embodiment, and the comparative example.

[0395] like Fig.26 As shown, it can be seen that in this modification, Rayleigh waves, which are unnecessary waves outside the frequency band, can be further suppressed. In addition, although not shown in the figure, in this modification, the transverse mode can also be suppressed in both first elastic wave resonator 31A and second elastic wave resonator 31D. Therefore, the transverse mode can also be effectively suppressed as the elastic wave device as a whole.

[0396] exist Fig. 27 In the third modification shown in FIG. 1 , a first elastic wave resonator 31C has the same structure as the first elastic wave resonator 1C in the first modification of the first embodiment. In the first elastic wave resonator 31C, a plurality of electrode fingers are bent so as to face the first elastic wave resonator 31C. Fig. 27 The second elastic wave resonator 31D is configured similarly to the third modification of the first embodiment. In the second elastic wave resonator 31D, the plurality of electrode fingers are bent so as to protrude toward the right side. Fig. 27 The left side of the .

[0397] In this modification, in first elastic wave resonator 31C and second elastic wave resonator 31D, both of which are excitation angle variable resonators, the first envelope and the second envelope have at least one bend, thereby effectively suppressing the transverse mode of the entire elastic wave device.

[0398] In describing the configurations of the above-mentioned embodiments and modifications, a plurality of examples of the excitation angle variable resonator are shown. As examples of the configurations in the intersection region of the excitation angle variable resonator, the following first to third configurations can be cited.

[0399] The first structure is Figure 3 The structure shown in the first embodiment or the description thereof is a structure in which the shapes of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view include the shapes of circular arcs or elliptical arcs.

[0400] The second structure is Fig. 9 The structure of the first variant of the first embodiment shown in FIG. That is, the shape of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view is curved and the curvature of each of the first electrode fingers and the second electrode fingers is not constant. Furthermore, the second structure is a structure in which the curvatures of the front end portions located on the first envelope side in at least one group of electrode fingers among the plurality of first electrode fingers and the plurality of second electrode fingers are different from each other, between adjacent portions, or between the front end portions and adjacent portions.

[0401] The third structure is Fig.12 The structure of the second variant of the first embodiment shown in FIG. That is, it is a structure including a plurality of parallel regions in which a plurality of first electrode fingers and a plurality of second electrode fingers extend in parallel, and a non-parallel region in which the directions in which the plurality of first electrode fingers and the plurality of second electrode fingers extend intersect with each other. Moreover, the third structure is a structure in which parallel regions and non-parallel regions are alternately arranged in at least a portion of the intersection region. Furthermore, the third structure is a structure in which a plurality of first electrode fingers and a plurality of second electrode fingers extend linearly in a plurality of parallel regions and non-parallel regions, respectively, and are bent at the boundary between the parallel region and the non-parallel region.

[0402] It is preferable that the structure of the intersection region of at least one excitation angle variable resonator is any one of the first to third structures. This makes it possible to more reliably suppress unnecessary waves outside the frequency band.

[0403] In addition, the first to third structures refer to the types of structures of the intersection region. For example, when the structures of the intersection regions of both excitation angle variable resonators are the same structures among the first to third structures, it also includes the case where the parameters such as duty ratio and electrode finger pitch in the intersection regions of both parties are different from each other.

[0404] As in the first and second embodiments described above, at least one of the plurality of elastic wave resonators may be an elastic wave resonator that is not an excitation angle variable resonator. In this case, the structure of the intersection region of the elastic wave resonator may be any one of the first to third structures and a structure in which the shape of the plurality of electrode fingers in a plan view is a straight line. However, in the present invention, at least one of the plurality of elastic wave resonators is an excitation angle variable resonator.

[0405] Preferably, at least two of the plurality of elastic wave resonators are excitation angle variable resonators, and the structures in the intersection region of the at least two excitation angle variable resonators are any of the first to third structures that are different from each other. In this case, the shapes of the electrode fingers in the at least two excitation angle variable resonators when viewed from above are different from each other. This makes it possible to more reliably suppress out-of-band unnecessary waves as a whole elastic wave device.

[0406] However, when the structures of the intersection regions of the plurality of variable excitation angle resonators are different from each other, the structure of the intersection region of at least one variable excitation angle resonator may be Fig.14 The third modification example of the first embodiment shown in the figure is other than the first to third structures.

[0407] More preferably, all elastic wave resonators in the elastic wave device are variable excitation angle resonators, and the shapes of the electrode fingers in all variable excitation angle resonators are different from each other. This can more reliably suppress out-of-band unnecessary waves.

[0408] In the excitation angle variable resonator, the first envelope and the second envelope may have any one of the following fourth to sixth structures. The fourth structure is Fig. 9 The structure of the first modified example of the first embodiment shown in FIG. 1 is a structure in which both the first envelope and the second envelope have a shape having at least one bent portion whose extending direction changes.

[0409] The fifth structure is Fig. 20 The structure of the 9th variant of the first embodiment shown in FIG. That is, the first envelope and the second envelope are both straight lines and extend in parallel. In the fifth structure, the direction in which the first envelope and the second envelope extend may be parallel to the direction in which the propagation axis of the piezoelectric layer 6 extends, or may intersect with the direction in which the propagation axis extends.

[0410] The sixth structure is Figure 3The structure of the first embodiment shown in FIG. That is, the first envelope and the second envelope are both linear and the direction in which the first envelope extends intersects the direction in which the second envelope extends. In addition, the sixth structure is not limited to the structure in which the first envelope and the second envelope are arranged in line symmetry. Specifically, for example, the absolute value of the angle formed by the first envelope and the direction in which the propagation axis extends, and the absolute value of the angle formed by the second envelope and the direction in which the propagation axis extends are different from each other. This example includes the intersection angle θ C1_AP The absolute value and intersection angle θ C2_AP More specifically, for example, the intersection angle θ may be different from each other. C1_AP is 10°, and the intersection angle θ C2_AP Or, for example, the intersection angle θ C1_AP is 10°, the crossing angle θ C2_AP is 0°.

[0411] At least two of the plurality of elastic wave resonators may be variable excitation angle resonators, and the structures of the first envelope and the second envelope of the at least two variable excitation angle resonators may be any of the fourth to sixth structures that are different from each other.

[0412] Fig.28 It is a schematic plan view of an elastic wave device according to a fourth embodiment.

[0413] The present embodiment is different from the third embodiment in that both first elastic wave resonator 31A and second elastic wave resonator 41A have the same structure as first elastic wave resonator 31A in the third embodiment. In second elastic wave resonator 41A, a plurality of electrode fingers are bent so as to face the first elastic wave resonator 31A. Fig.28 The left side of the image is convex. Except for the above-described points, the elastic wave device of the present embodiment has the same structure as the elastic wave device 31 of the third embodiment.

[0414] In this embodiment, as in the third embodiment, the plurality of elastic wave resonators of the elastic wave device include an excitation angle variable resonator. This makes it possible to suppress unnecessary out-of-band waves.

[0415] The structure of the intersection region of both first elastic wave resonator 31A and second elastic wave resonator 41A is the first structure described above. Specifically, the shape of the plurality of electrode fingers in a plan view is an arc shape. However, the duty ratios of first elastic wave resonator 31A and second elastic wave resonator 41A are different from each other. Therefore, the shapes of the electrode fingers in the intersection region of first elastic wave resonator 31A and second elastic wave resonator 41A are different from each other.

[0416] More specifically, the excitation angle θ in the first elastic wave resonator 31A is C_prop The duty ratio is 0.626 for the portion where the excitation angle is 0°. C_prop The larger the |, the smaller the duty cycle.

[0417] On the other hand, the excitation angle θ in the second elastic wave resonator 41A is C_prop The duty ratio is 0.5 for the portion where the excitation angle is 0°. C_prop The larger the |, the smaller the duty cycle.

[0418] In each of first elastic wave resonator 31A and second elastic wave resonator 41A, the duty ratio is changed according to the excitation angle θ C_prop The duty cycle may be constant in the entire cross region. In this case, the electrode finger pitch, the electrode finger thickness, and other parameters other than the duty cycle may be changed according to the excitation angle θ. C_prop The resonant frequency or the anti-resonant frequency changes so that it is substantially consistent in the entire intersection region.

[0419] The plurality of elastic wave resonators of the elastic wave device may include elastic wave resonators other than the first elastic wave resonator 31A and the second elastic wave resonator 41A as the excitation angle variable resonators. In this case, it is also preferable that the excitation angle θ of at least two of the excitation angle variable resonators is θ . C_prop The duty ratios in the portions where the excitation angle is 0° are different from each other. In addition, it is preferred that at least the excitation angle θ C_prop The duty ratio in the portion of 0° is constant. This makes it possible to more reliably and effectively suppress unnecessary waves outside the frequency band as the entire elastic wave device.

[0420] In the present embodiment, in first elastic wave resonator 31A and second elastic wave resonator 41A, both of which are excitation angle variable resonators, the structures of both the first envelope and the second envelope are the sixth structure. Specifically, both the first envelope and the second envelope are linear, the direction in which the first envelope extends intersects the direction in which the second envelope extends, and the first envelope and the second envelope are arranged to be line-symmetrical with respect to a symmetry axis passing through the center of the intersection region. Thus, the transverse mode can be effectively suppressed as the elastic wave device as a whole.

[0421] However, the first envelope and the second envelope may have structures other than the sixth structure. Fig.29In the modified example of the fourth embodiment shown in FIG. 1 , the first elastic wave resonator 31J and the second elastic wave resonator 41J have the same Fig. 20 The structure of the first elastic wave resonator 1J in the ninth variation of the first embodiment shown in FIG. 1 is the same as that of the first elastic wave resonator 1J in the ninth variation of the first embodiment shown in FIG. Fig.29 In the second elastic wave resonator 41J, a plurality of electrode fingers are bent so as to protrude toward the right side. Fig.29 The left side of the .

[0422] In this modification, in first elastic wave resonator 31J and second elastic wave resonator 41J, both of which are excitation angle variable resonators, the structures of the first envelope and the second envelope are the sixth structure. Specifically, the first envelope and the second envelope are both linear and extend in parallel.

[0423] The duty ratios of the first elastic wave resonator 31J and the second elastic wave resonator 41J are the same as those of the third embodiment. More specifically, the excitation angle θ in the first elastic wave resonator 31J is C_prop The duty ratio is 0.626 for the portion where the excitation angle is 0°. C_prop The larger the |, the smaller the duty cycle.

[0424] On the other hand, the excitation angle θ in the second elastic wave resonator 41J is C_prop The duty ratio is 0.5 for the portion where the excitation angle is 0°. C_prop The larger the |, the smaller the duty cycle.

[0425] In the fourth embodiment and its modified example, the excitation angle variable resonators have the same structure of the intersection region, but have different duty ratios, thereby making the shapes of the electrode fingers different. However, the present invention is not limited to this.

[0426] For example, the electrode finger pitches of at least two variable excitation angle resonators may be different from each other. In this case, for example, at least the excitation angle θ of each of the at least two variable excitation angle resonators is different from each other. C_prop The electrode finger pitch in the portion where the excitation angle is 0° is constant. C_prop The electrode finger pitches in the portions at 0° are different from each other.

[0427] Alternatively, the curvatures of the electrode fingers in at least two variable excitation angle resonators are different from each other. In this case, for example, in each of the at least two variable excitation angle resonators, the shape of the plurality of electrode fingers in a plan view is a curved shape. The curvatures of at least one of the electrode fingers in the outermost direction and the electrode fingers in the innermost direction of the at least two variable excitation angle resonators are different from each other.

[0428] As described above, the outer direction refers to the direction in which the curved portion of the electrode finger protrudes in the direction in which the plurality of electrode fingers are arranged. The direction opposite to the outer direction is the inner direction. More specifically, the inner direction is the direction in which the curved portion of the electrode finger is recessed in the direction in which the plurality of electrode fingers are arranged.

[0429] Alternatively, in at least two variable excitation angle resonators, the excitation angle θ may be C_prop For example, the excitation angle θ of the two excitation angle variable resonators may be different from each other. C_prop The maximum values ​​of the positive direction of are different from each other. It is also possible that the excitation angle θ C_prop Alternatively, the excitation angle θ may be different in both directions. C_prop The positive maximum value and the negative maximum value are different from each other.

[0430] For example, the structures of the first envelope and the second envelope in both excitation angle variable resonators are as follows: Fig.28 In the sixth structure such as the first elastic wave resonator 31A and the second elastic wave resonator 41A shown in FIG. C_prop In this case, the cross angle θ of the two excitation angle variable resonators is different from each other. C1_AP The absolute values ​​of are different from each other. Similarly, on both sides, the intersection angle θ C2_AP The absolute values ​​of are also different from each other.

[0431] In the first to fourth embodiments, an example is shown in which the elastic wave device includes two elastic wave resonators as the plurality of elastic wave resonators. However, the elastic wave device may include at least three elastic wave resonators as the plurality of elastic wave resonators. This example is shown below.

[0432] Fig.30 It is a schematic plan view of an elastic wave device according to a fifth embodiment.

[0433] The present embodiment differs from the third embodiment in that the elastic wave device 51 includes a third elastic wave resonator 51C as an excitation angle variable resonator. Except for the above, the elastic wave device 51 of the present embodiment has the same structure as the elastic wave device 31 of the third embodiment. In addition, the elastic wave device 51 includes the first elastic wave resonator 31A and the second elastic wave resonator 41C as in the third embodiment. The elastic wave device 51 includes three excitation angle variable resonators.

[0434] First elastic wave resonator 31A, second elastic wave resonator 41C, and third elastic wave resonator 51C are sequentially connected in series with one another.

[0435] Third elastic wave resonator 51C is constructed similarly to second elastic wave resonator 41C. However, the curvature of the electrode fingers and the direction in which the electrode fingers are bent are different in second elastic wave resonator 41C and third elastic wave resonator 51C. In second elastic wave resonator 41C, a plurality of electrode fingers are bent so as to face the electrode fingers in the opposite direction. Fig.30 On the other hand, in the third elastic wave resonator 51C, the plurality of electrode fingers are bent so as to protrude to the left. Fig.30 The right side of the figure is protruding.

[0436] In the elastic wave device having the structure of this embodiment and Figure 6 The phase characteristics of the elastic wave devices of the comparative examples shown in FIG. 1 are compared. In addition, the results of the first embodiment are also shown. The design parameters of the first embodiment and the comparative example involved in this comparison are as follows: Fig.23 The first embodiment and the comparative example shown in the comparison are the same.

[0437] The design parameters of the elastic wave resonator having the structure of the first elastic wave resonator 31A in the present embodiment are the same as Fig.23 The comparison shown is the same as the third embodiment.

[0438] Crossing angle θ C1_AP : 7.5°

[0439] Crossing angle θ C2_AP : -7.5°

[0440] The design parameters of the elastic wave resonator having the structure of the second elastic wave resonator 41C in the present embodiment are as follows, except for the excitation angle on the first envelope and the excitation angle on the second envelope. Fig.23 The comparison shown is the same as the third embodiment.

[0441] Excitation angle on the first envelope line: θ C_AP1_1 =13.5°,θ C_AP1_2 =9°,θC_AP1_3 =16.5°,θ C_AP1_4 =9°,θ C_AP1_5 =16°,θ C_AP1_6 =9°

[0442] Excitation angle on the second envelope line: θ C_AP2_1 =10°,θ C_AP2_2 =16.5°,θ C_AP2_3 =10°,θ C_AP2_4 =17°,θ C_AP2_5 =9.5°,θ C_AP2_6 =16°

[0443] The design parameters of the elastic wave resonator having the structure of the third elastic wave resonator 51C in the present embodiment are as follows: Fig.23 The design parameters of the elastic wave resonator having the structure of the second elastic wave resonator 41C in the third embodiment according to the comparison are the same.

[0444] Fig.31 It is a diagram showing phase characteristics in the vicinity of the frequency at which unnecessary waves are generated in the first embodiment, the fifth embodiment, and the comparative example.

[0445] like Fig.31 As shown, it can be seen that in the first embodiment, the Rayleigh wave, which is an unnecessary wave, can be suppressed compared to the comparative example. Furthermore, it can be seen that in the fifth embodiment, the Rayleigh wave can be further suppressed. In addition, although not shown, in the fifth embodiment, the transverse mode can be suppressed in all of the first elastic wave resonator 31A, the second elastic wave resonator 41C, and the third elastic wave resonator 51C. Therefore, the transverse mode can be effectively suppressed as the elastic wave device 51.

[0446] As in the fifth embodiment, at least three of the plurality of elastic wave resonators may be excitation angle variable resonators. Furthermore, it is preferred that the shapes of the electrode fingers in the plan view are different from each other in at least three excitation angle variable resonators. In the fifth embodiment, the structures of the cross regions are different between the first elastic wave resonator 31A and the other elastic wave resonators, and thus the shapes of the electrode fingers in the plan view are different from each other. In the second elastic wave resonator 41C and the third elastic wave resonator 51C, the curvatures of the electrode fingers are different from each other, and thus the shapes of the electrode fingers in the plan view are different from each other. As a result, it is possible to more reliably suppress unwanted waves outside the frequency band as a whole elastic wave device.

[0447] However, for example, the duty ratios of second elastic wave resonator 41C and third elastic wave resonator 51C may be different from each other, thereby making the shapes of the electrode fingers different from each other. As an example, the excitation angle θ in second elastic wave resonator 41C is as follows: C_propThe duty ratio is 0.626 for the portion where the excitation angle θ is 0°. C_prop For the portion at 0°, the duty cycle is 0.5.

[0448] The structure of the cross region of the excitation angle variable resonator in the elastic wave device, the structure of the first envelope, and the structure of the second envelope are not particularly limited. Fig.32 In the modification of the fifth embodiment shown in FIG. 1 , the structure of the intersection region of the third elastic wave resonator 51D is the third structure described above. That is, the shape of the plurality of electrode fingers of the third elastic wave resonator 51D in a plan view is a shape that is bent at a plurality of nodes. In this modification, the first elastic wave resonator 31A and the second elastic wave resonator 41C are configured similarly to those of the fifth embodiment.

[0449] In this modification, as in the fifth embodiment, it is possible to suppress unnecessary waves and transverse modes outside the frequency band.

[0450] In addition, the stacked structure of the piezoelectric substrate is not limited to Figure 4 The sixth embodiment shows an example in which the elastic wave device has a piezoelectric substrate different from that of the first embodiment.

[0451] Fig.33 It is a schematic front cross-sectional view of an elastic wave device according to a sixth embodiment.

[0452] This embodiment is different from the first embodiment in the stacked structure of the piezoelectric substrate 62. Fig.33 , the first IDT electrode 18A is shown. Although not shown, the second IDT electrode 18B similar to that of the first embodiment is also provided on the piezoelectric substrate 62. Except for the above-mentioned points, the elastic wave device of this embodiment has the same structure as the elastic wave device 1 of the first embodiment.

[0453] The piezoelectric substrate 62 includes a supporting substrate 4, an intermediate layer 65, and a piezoelectric layer 6. The intermediate layer 65 is provided on the supporting substrate 4. The piezoelectric layer 6 is provided on the intermediate layer 65. In the present embodiment, the intermediate layer 65 has a frame-like shape. That is, the intermediate layer 65 has a through hole. The supporting substrate 4 blocks one side of the through hole of the intermediate layer 65. The piezoelectric layer 6 blocks the other side of the through hole of the intermediate layer 65. Thus, a hollow portion 62c is formed in the piezoelectric substrate 62. A portion of the piezoelectric layer 6 and a portion of the supporting substrate 4 are opposed to each other with the hollow portion 62c sandwiched therebetween.

[0454] In this embodiment, the main mode can be reflected toward the piezoelectric layer 6. Therefore, the energy of the elastic wave can be effectively confined in the piezoelectric layer 6. In addition, as in the first embodiment, unnecessary waves outside the frequency band can be suppressed.

[0455] The following shows the first and second variants of the sixth embodiment, in which only the stacked structure of the piezoelectric substrate is different from that of the sixth embodiment. In the first and second variants, as in the sixth embodiment, it is possible to suppress useless waves outside the frequency band and effectively confine the energy of the elastic waves on the piezoelectric layer 6 side.

[0456] exist Fig.34 In the first modified example shown, the piezoelectric substrate 62A includes a supporting substrate 4, an acoustic reflection film 67, an intermediate layer 65A, and a piezoelectric body layer 6. The acoustic reflection film 67 is provided on the supporting substrate 4. The intermediate layer 65A is provided on the acoustic reflection film 67. The piezoelectric body layer 6 is provided on the intermediate layer 65A. The intermediate layer 65A is a low acoustic velocity film.

[0457] The acoustic reflection film 67 is a laminate of multiple acoustic impedance layers. Specifically, the acoustic reflection film 67 has multiple low acoustic impedance layers and multiple high acoustic impedance layers. The high acoustic impedance layer is a layer with relatively high acoustic impedance. More specifically, the multiple high acoustic impedance layers of the acoustic reflection film 67 are high acoustic impedance layer 67a, high acoustic impedance layer 67c, and high acoustic impedance layer 67e. On the other hand, the low acoustic impedance layer is a layer with relatively low acoustic impedance. More specifically, the multiple low acoustic impedance layers of the acoustic reflection film 67 are low acoustic impedance layer 67b and low acoustic impedance layer 67d. The low acoustic impedance layers and the high acoustic impedance layers are alternately laminated. In addition, the high acoustic impedance layer 67a is the layer located closest to the piezoelectric layer 6 in the acoustic reflection film 67.

[0458] The acoustic reflective film 67 has two low acoustic impedance layers and three high acoustic impedance layers. However, the acoustic reflective film 67 only needs to have at least one low acoustic impedance layer and one high acoustic impedance layer.

[0459] As the material of the low acoustic impedance layer, for example, silicon oxide or aluminum can be used. As the material of the high acoustic impedance layer, for example, metals such as platinum or tungsten, and dielectrics such as aluminum nitride or silicon nitride can be used. In addition, the material of the intermediate layer 65A can also be the same as the material of the low acoustic impedance layer.

[0460] exist Fig.35 In the second variation shown, the piezoelectric substrate 62B has a support substrate 64 and a piezoelectric layer 6. The piezoelectric layer 6 is directly provided on the support substrate 64. More specifically, the support substrate 64 has a recess. The piezoelectric layer 6 is provided on the support substrate 64 so as to block the recess. Thus, a hollow portion is provided in the piezoelectric substrate 62B. The hollow portion overlaps with at least a portion of the first IDT electrode 18A in a plan view.

[0461] Fig.36 It is a schematic front cross-sectional view of an elastic wave device according to a seventh embodiment.

[0462] The present embodiment is different from the first embodiment in that the first IDT electrode 18A is buried in the protective film 79. Although not shown in the figure, the present embodiment is also different from the first embodiment in that Figure 1 The second IDT electrode 18B shown is buried in the protective film 79. Except for the above-described points, the elastic wave device of the present embodiment has the same structure as the elastic wave device 1 of the first embodiment.

[0463] Specifically, a protective film 79 is provided on the piezoelectric layer 6 so as to cover the first IDT electrode 18A. The thickness of the protective film 79 is thicker than the thickness of the first IDT electrode 18A. The first IDT electrode 18A is buried in the protective film 79. Thus, the first IDT electrode 18A is not easily damaged. Similarly, the second IDT electrode 18B is not easily damaged.

[0464] The protective film 79 includes a first protective layer 79a and a second protective layer 79b. The first IDT electrode 18A and the second IDT electrode 18B are embedded in the first protective layer 79a. The second protective layer 79b is provided on the first protective layer 79a. Thus, multiple effects can be obtained by the protective film 79. Specifically, in the present embodiment, silicon oxide is used as the material of the first protective layer 79a. Thus, the absolute value of the temperature coefficient of frequency (TCF) in the elastic wave device can be reduced. Therefore, the temperature characteristics of the elastic wave device can be improved. Silicon nitride is used in the second protective layer 79b. Thus, the moisture resistance of the elastic wave device can be improved.

[0465] Furthermore, in the present embodiment, the first IDT electrode 18A and the second IDT electrode 18B are configured and arranged in the same manner as in the first embodiment. This makes it possible to suppress unnecessary waves outside the frequency band.

[0466] The materials of the first protective layer 79a and the second protective layer 79b are not limited to those described above. The protective film 79 may be a single layer or a laminate of three or more layers.

[0467] Fig.37 It is a schematic front cross-sectional view of an elastic wave device according to an eighth embodiment.

[0468] The present embodiment is different from the first embodiment in that a first IDT electrode 18A is provided on both the first principal surface 6a and the second principal surface 6b of the piezoelectric layer 6. Although not shown in the figure, the present embodiment is also different from the first embodiment in that a first IDT electrode 18A is provided on both the first principal surface 6a and the second principal surface 6b of the piezoelectric layer 6. Figure 1The first IDT electrode 18A and the second IDT electrode 18B provided on the second main surface 6b are embedded in the second layer 5b of the intermediate layer 5. Except for the above-mentioned points, the elastic wave device 81 of the present embodiment has the same structure as the elastic wave device 1 of the first embodiment.

[0469] The first IDT electrode 18A provided on the first principal surface 6a of the piezoelectric layer 6 and the first IDT electrode 18A provided on the second principal surface 6b face each other with the piezoelectric layer 6 interposed therebetween. The second IDT electrode 18B provided on the first principal surface 6a of the piezoelectric layer 6 and the second IDT electrode 18B provided on the second principal surface 6b face each other with the piezoelectric layer 6 interposed therebetween.

[0470] In the elastic wave device 81 of the present embodiment, the first IDT electrode 18A and the second IDT electrode 18B are configured similarly to the first embodiment on the first main surface 6a. Furthermore, the first IDT electrode 18A and the second IDT electrode 18B are connected without passing through the functional electrodes of other elastic wave resonators. The same is true for the second main surface 6b. Thus, as in the first embodiment, it is possible to suppress unnecessary waves outside the frequency band.

[0471] Furthermore, the first IDT electrodes 18A provided on the first principal surface 6a and the second principal surface 6b of the piezoelectric layer 6 may have different design parameters. The second IDT electrodes 18B provided on the first principal surface 6a and the second principal surface 6b may have different design parameters.

[0472] The following describes the first to third variations of the eighth embodiment, in which only the structure of the electrode provided on the second main surface of the piezoelectric layer and at least one of the stacked structure of the piezoelectric substrate are different from the eighth embodiment. In the first to third variations, as in the eighth embodiment, it is possible to suppress unnecessary waves outside the frequency band.

[0473] exist Fig.38 In the first variation shown, the piezoelectric substrate 62 is configured similarly to the sixth embodiment. Specifically, the piezoelectric substrate 62 includes a support substrate 4, an intermediate layer 65, and a piezoelectric layer 6. The first IDT electrode 18A provided on the second main surface 6b of the piezoelectric layer 6 is located in the hollow portion 62c. Although not shown, similarly, the second IDT electrode 18B provided on the second main surface 6b is also located in the hollow portion 62c.

[0474] exist Fig.39In the second modification shown, a plate-shaped electrode 88 is provided on the second main surface 6b of the piezoelectric layer 6. The first IDT electrode 18A and the electrode 88 are opposed to each other with the piezoelectric layer 6 sandwiched therebetween. In addition, another electrode 88 is provided on the second main surface 6b so as to be opposed to the second IDT electrode 18B. Each electrode 88 is buried in the second layer 5b.

[0475] exist Fig.40 In the third modification shown, the piezoelectric substrate 62 is configured similarly to the first modification, and an electrode 88 similar to the second modification is provided on the second principal surface 6b of the piezoelectric layer 6. The electrode 88 is located in the hollow portion 62c.

[0476] In the sixth to eighth embodiments and each modified example, an example is shown in which the first IDT electrode and the second IDT electrode have the same structure and configuration as the first embodiment. However, the piezoelectric substrate of the sixth to eighth embodiments and each modified example can also be adopted when the structure and configuration of the plurality of IDT electrodes are set to the structure and configuration of the present invention other than the first embodiment.

[0477] Examples of aspects of the elastic wave device according to the present invention are summarized below.

[0478] <1> An elastic wave device for a filter device, the elastic wave device comprising a plurality of elastic wave resonators, the plurality of elastic wave resonators respectively comprising: a piezoelectric substrate having a piezoelectric layer; and an IDT electrode disposed on the piezoelectric substrate and having a plurality of electrode fingers, at least one of the plurality of elastic wave resonators being an excitation angle variable resonator, in which the piezoelectric layer has a propagation axis, the plurality of electrode fingers being bent, and in which the excitation direction of an elastic wave in any portion of any electrode finger among the plurality of electrode fingers is any one of a first direction to a third direction, the first direction being parallel to the first direction. The second direction is a direction perpendicular to the direction in which the electrode finger extends, the second direction is a direction connecting the shortest distance between the electrode finger and the electrode finger adjacent to the electrode finger, the third direction is a direction of the electric field vector generated between the electrode finger and the electrode finger adjacent to the electrode finger, in the excitation angle variable resonator, when the angle formed by the excitation direction and the direction in which the propagation axis extends is set as the excitation angle, in the IDT electrode, the excitation angle is different, the multiple elastic wave resonators are connected in series or in parallel with each other, no other elements are connected between the multiple elastic wave resonators, and the circuit of the filter device is not branched between the multiple elastic wave resonators.

[0479] <2> The elastic wave device according to <1>, wherein at least two of the plurality of elastic wave resonators are variable excitation angle resonators, and wherein the electrode fingers of the at least two variable excitation angle resonators have different shapes in a plan view.

[0480] <3> The elastic wave device according to <2>, wherein the plurality of elastic wave resonators are at least three of the elastic wave resonators, at least three of the plurality of elastic wave resonators are variable excitation angle resonators, and the shapes of the electrode fingers in the plan view are different from each other in the at least three variable excitation angle resonators.

[0481] <4> An elastic wave device according to <2> or <3>, wherein in each of at least two of the excitation angle-variable resonators, the duty cycle in at least the portion where the excitation angle is 0° is fixed, and in at least two of the excitation angle-variable resonators, the duty cycles in the portion where the excitation angle is 0° are different from each other.

[0482] <5>According to <2> ~ <4> An elastic wave device as described in any one of the above, wherein in each of at least two of the excitation angle-variable resonators, the electrode finger spacing in at least the portion where the excitation angle is 0° is fixed, and in at least two of the excitation angle-variable resonators, the electrode finger spacing in the portion where the excitation angle is 0° is different from each other.

[0483] <6> according to <2> ~ <5> An elastic wave device as described in any one of the items, wherein, in each of at least two of the excitation angle change-type resonators, the shape of the plurality of electrode fingers when viewed from above is curved, a direction in which the curved portion of the electrode fingers protrudes in the direction in which the plurality of electrode fingers are arranged is set as an outer direction, and a direction in which the curved portion of the electrode fingers is recessed in the direction in which the plurality of electrode fingers are arranged is set as an inner direction, at this time, in at least two of the excitation angle change-type resonators, the curvatures of at least one of the electrode fingers closest to the outer direction and the electrode fingers closest to the inner direction are different from each other.

[0484] <7> according to <2> ~ <6> The elastic wave device according to any one of claims 1 to 5, wherein the ranges of the excitation angles in at least two of the variable excitation angle resonators are different from each other.

[0485] <8> according to <1> ~ <7> The elastic wave device as described in any one of the above, wherein the plurality of electrode fingers in the IDT electrode of the excitation angle-variable resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other, a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers is set as a first envelope, a virtual line formed by connecting the front ends of the front ends of the plurality of first electrode fingers is set as a second envelope, a region between the first envelope and the second envelope in the IDT electrode is a crossing region, and the first envelope is a first electrode finger. The portion of the pole finger including the portion located on the first envelope and adjacent to the front end portion of any of the second electrode fingers is the adjacent portion of the first electrode finger, the portion of the second electrode finger including the portion located on the second envelope and adjacent to the front end portion of any of the first electrode fingers is the adjacent portion of the second electrode finger, the structure in the intersection region of at least one of the excitation angle variable resonators is any one of the first structure to the third structure, the first structure is a top view of the plurality of first electrode fingers and the plurality of second electrode fingers The shape below includes a shape of a circular arc or an elliptical arc, the second structure is a structure in which the shapes of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view are curved, the curvatures of the respective first electrode fingers and the second electrode fingers are not constant, and the curvatures of the front end portions located on the first envelope side in at least one group of electrode fingers among the plurality of first electrode fingers and the plurality of second electrode fingers are different from each other, between the adjacent portions, or between the front end portions and the adjacent portions, and the third structure is a structure in which the intersection region includes a plurality of parallel regions in which the plurality of first electrode fingers and the plurality of second electrode fingers extend in parallel, and non-parallel regions in which the directions in which the plurality of first electrode fingers and the plurality of second electrode fingers extend intersect with each other, the parallel regions and the non-parallel regions are alternately arranged in at least a portion of the intersection region, the plurality of first electrode fingers and the plurality of second electrode fingers extend linearly in the plurality of parallel regions and the non-parallel regions, respectively, and are bent at boundaries between the parallel regions and the non-parallel regions.

[0486] <9> The elastic wave device according to <8>, wherein at least one of the excitation angle-variable resonators has a pair of reflectors, the pair of reflectors are arranged on the piezoelectric layer to be opposite to each other with the IDT electrode sandwiched therebetween, and each of the reflectors has a plurality of reflector electrode fingers, the structure in the intersection region of at least one of the excitation angle-variable resonators is one of the first structure and the second structure, and the shapes of the plurality of reflector electrode fingers when viewed from above include curved shapes.

[0487] <10> according to <8> The elastic wave device, wherein at least one of the excitation angle variable resonators has a pair of reflectors, the pair of reflectors are arranged on the piezoelectric layer to be opposite to each other with the IDT electrode sandwiched therebetween, and each has a plurality of reflector electrode fingers, the structure in the intersection region of at least one of the excitation angle variable resonators is the third structure, and the shapes of the plurality of reflector electrode fingers in a plan view include shapes bent at a plurality of nodes.

[0488] <11> according to <8> ~ <10> An elastic wave device as described in any one of the items , wherein at least two of the plurality of elastic wave resonators are the excitation angle variable resonators, and the structure in the intersection region of at least two of the excitation angle variable resonators is any one of the first to third structures that are different from each other.

[0489] <12> according to <1> ~ <11> The elastic wave device according to any one of the preceding claims, wherein the plurality of electrode fingers in the IDT electrode of the excitation angle-variable resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other, a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers is set as a first envelope, a virtual line formed by connecting the front ends of the front ends of the plurality of first electrode fingers is set as a second envelope, a region between the first envelope and the second envelope in the IDT electrode is a crossing region, and both the first envelope and the second envelope are A structure having a shape of at least one bent portion with a changing extension direction is set as the fourth structure, a structure in which the first envelope and the second envelope are both straight lines and extend in parallel is set as the fifth structure, and a structure in which the first envelope and the second envelope are both straight lines and the extending direction of the first envelope intersects the extending direction of the second envelope is set as the sixth structure. In this case, the structure of the first envelope and the second envelope of at least one of the excitation angle variable resonators is any one of the fourth to sixth structures.

[0490] <13> according to <12> The elastic wave device, wherein at least two of the plurality of elastic wave resonators are the excitation angle variable resonators, and the structures of the first envelope and the second envelope of at least two of the excitation angle variable resonators are any mutually different structures among the fourth structure to the sixth structure.

[0491] <14> according to <12> In the elastic wave device, in all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the fourth structure.

[0492] <15> according to <12> In the elastic wave device, in all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the fifth structure.

[0493] <16> according to <12> In the elastic wave device, in all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the sixth structure.

[0494] <17> according to <1> ~ <16> The elastic wave device according to any one of claims , wherein all of the elastic wave resonators are variable excitation angle resonators, and the shapes of the electrode fingers in a plan view are different from each other in all of the variable excitation angle resonators.

[0495] <18> according to <1> ~ <16> The elastic wave device according to any one of the above, wherein at least one of the plurality of elastic wave resonators is not the variable excitation angle resonator, and the plurality of electrode fingers of the elastic wave resonator that is not the variable excitation angle resonator have a linear shape in a plan view.

[0496] <19> according to <18> The elastic wave device, wherein, in the elastic wave resonator that is not the excitation angle variable resonator, the piezoelectric layer has a propagation axis, the multiple electrode fingers in the IDT electrode of the elastic wave resonator include a plurality of third electrode fingers and a plurality of fourth electrode fingers that are interlaced with each other, a virtual line formed by connecting the front ends of the front ends of the plurality of fourth electrode fingers is set as the third envelope, and a virtual line formed by connecting the front ends of the front ends of the plurality of third electrode fingers is set as the fourth envelope, and at this time, the third envelope and the fourth envelope are inclined relative to the propagation axis.

[0497] <20> according to <1> ~ <19> The elastic wave device according to any one of claims 1 to 5, wherein at least one of an electrode finger pitch and a duty ratio is constant in a portion of the IDT electrode of at least one of the variable excitation angle resonators where the excitation angle is the same.

[0498] <21> according to <1> ~ <20> An elastic wave device as described in any one of the items , wherein the plurality of electrode fingers in the IDT electrode of the excitation angle variable resonator include a plurality of first electrode fingers and a plurality of second electrode fingers which are interlaced with each other, a virtual line formed by connecting the front ends of the front end portions of the plurality of second electrode fingers is set as a first envelope, and a virtual line formed by connecting the front ends of the front end portions of the plurality of first electrode fingers is set as a second envelope, and a region between the first envelope and the second envelope in the IDT electrode is a crossover region, and in the crossover region of at least one of the excitation angle variable resonators, the resonant frequency or the antiresonant frequency is substantially consistent.

[0499] <22>According to <21> The elastic wave device described above, wherein at least two of the plurality of elastic wave resonators are the excitation angle variable resonators, and in each of the intersection regions of at least two of the excitation angle variable resonators, the resonant frequencies are substantially consistent, and the following relationship holds true between at least two of the excitation angle variable resonators: when the resonant frequency of a portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, a difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially consistent in the intersection region is less than 2% relative to the reference resonant frequency of any one of the two excitation angle variable resonators.

[0500] <23> according to <21> The elastic wave device described above, wherein at least one of the plurality of elastic wave resonators is not the excitation angle variable resonator, and in the intersection region of at least one of the excitation angle variable resonators, the resonant frequencies are substantially consistent, and in at least one of the excitation angle variable resonators and at least one of the elastic wave resonators that is not the excitation angle variable resonator, the following relationship holds: when the resonant frequency of the portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, the difference between the reference resonant frequency of the excitation angle variable resonator whose resonant frequencies are substantially consistent in the intersection region and the resonant frequency of the elastic wave resonator that is not the excitation angle variable resonator is less than 2% relative to either the reference resonant frequency or the resonant frequency.

[0501] <24> according to <21> The elastic wave device described above, wherein at least two of the plurality of elastic wave resonators are the excitation angle variable resonators, and in each of the intersection regions of at least two of the excitation angle variable resonators, the resonant frequencies are substantially consistent, and the following relationship holds true between at least two of the excitation angle variable resonators: when the resonant frequency of a portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, a difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially consistent in the intersection region is greater than 2% relative to the reference resonant frequency of any one of the two excitation angle variable resonators.

[0502] <25> According to the elastic wave device described in <21>, at least one of the multiple elastic wave resonators is not the excitation angle variable resonator, and in the intersection region of at least one of the excitation angle variable resonators, the resonant frequency is substantially consistent, and the following relationship holds true in at least one of the excitation angle variable resonators and at least one of the elastic wave resonators that is not the excitation angle variable resonator: when the resonant frequency of the portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, the difference between the reference resonant frequency of the excitation angle variable resonator whose resonant frequency is substantially consistent in the intersection region and the resonant frequency of the elastic wave resonator that is not the excitation angle variable resonator is greater than 2% relative to either the reference resonant frequency or the resonant frequency.

[0503] <26> according to <1> ~ <25> The elastic wave device according to any one of the preceding claims, wherein the plurality of electrode fingers in the IDT electrode of the excitation angle variable resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other, a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers is set as a first envelope, and a virtual line formed by connecting the front ends of the front ends of the plurality of first electrode fingers is set as a second envelope, a region between the first envelope and the second envelope in the IDT electrode is a crossing region, the crossing region includes a first edge region including the first envelope, a second edge region including the second envelope, and a central region sandwiched by the first edge region and the second edge region, and in at least one of the excitation angle variable resonators, at least a portion of at least one of the first edge region and the second edge region constitutes a low sound velocity region having a sound velocity lower than that in the central region.

[0504] <27> The elastic wave device according to <26>, wherein in at least one of the first edge region and the second edge region, at least one of the electrode fingers has a wide portion having a width wider than that in the central region, thereby forming the low acoustic velocity region.

[0505] <28> The elastic wave device according to <26> or <27>, wherein a mass addition film is provided in at least one of the first edge region and the second edge region, and the mass addition film is arranged to overlap with at least one of the plurality of first electrode fingers and the plurality of second electrode fingers when viewed from above, and the low acoustic velocity region is formed by providing the mass addition film.

[0506] <29> The elastic wave device according to any one of <26> to <28>, wherein in at least one of the first edge region and the second edge region, the thickness of at least one of the electrode fingers is thicker than that in the central region, thereby forming the low acoustic velocity region.

[0507] <30>According to <26> In the elastic wave device according to any one of items <29> to <29>, the low acoustic velocity region is formed entirely in both the first edge region and the second edge region.

[0508] <31> according to <1> In the elastic wave device according to any one of <30> to <30>, the piezoelectric substrate includes a supporting substrate, and the piezoelectric layer is provided on the supporting substrate.

[0509] <32> The elastic wave device according to <31>, wherein the piezoelectric substrate includes an intermediate layer provided between the supporting substrate and the piezoelectric layer.

[0510] <33> according to <32> In the elastic wave device, a hollow portion is formed in the piezoelectric substrate, and a portion of the support substrate and a portion of the piezoelectric layer are opposed to each other with the hollow portion interposed therebetween.

[0511] <34>According to <1> In the elastic wave device according to any one of items <30> to <30>, the piezoelectric substrate includes only the piezoelectric layer.

Claims

1. An elastic wave device for a filter device, The elastic wave device includes a plurality of elastic wave resonators, each of which includes: a piezoelectric substrate having a piezoelectric layer; and an IDT electrode provided on the piezoelectric substrate and having a plurality of electrode fingers. At least one of the plurality of elastic wave resonators is an excitation angle-variable resonator, In the excitation angle variation type resonator, the piezoelectric layer has a propagation axis, the plurality of electrode fingers are bent, In the variable excitation angle resonator, the excitation direction of the elastic wave in any portion of any electrode finger among the plurality of electrode fingers is any one of a first direction to a third direction, The first direction is a direction perpendicular to the direction in which the electrode fingers extend. The second direction is a direction connecting the electrode finger with the electrode finger adjacent to the electrode finger at the shortest distance. The third direction is the direction of the electric field vector generated between the electrode finger and the electrode finger adjacent to the electrode finger. In the excitation angle variable resonator, when the angle formed by the excitation direction and the direction in which the propagation axis extends is defined as an excitation angle, the excitation angle varies in the IDT electrode. The plurality of elastic wave resonators are connected in series or in parallel with each other, no other element is connected between the plurality of elastic wave resonators, and the circuit of the filter device does not branch between the plurality of elastic wave resonators.

2. The elastic wave device according to claim 1, wherein: At least two of the plurality of elastic wave resonators are the excitation angle-variable resonators, In at least two of the variable excitation angle resonators, the shapes of the electrode fingers in a plan view are different from each other.

3. The elastic wave device according to claim 2, wherein: The plurality of elastic wave resonators are at least three elastic wave resonators. At least three of the plurality of elastic wave resonators are the excitation angle-variable resonators, In at least three of the variable excitation angle resonators, the shapes of the electrode fingers in a plan view are different from each other.

4. The elastic wave device according to claim 2 or 3, wherein: In each of at least two of the variable excitation angle resonators, at least the duty ratio in the portion where the excitation angle is 0° is constant, and in at least two of the variable excitation angle resonators, the duty ratios in the portion where the excitation angle is 0° are different from each other.

5. The elastic wave device according to any one of claims 2 to 4, wherein: In each of at least two of the variable excitation angle resonators, at least the electrode finger pitch in the portion where the excitation angle is 0° is fixed, and in at least two of the variable excitation angle resonators, the electrode finger pitches in the portion where the excitation angle is 0° are different from each other.

6. The elastic wave device according to any one of claims 2 to 5, wherein: In each of at least two of the excitation angle change type resonators, the shape of the plurality of electrode fingers when viewed from above is curved, and the direction in which the curved portion of the electrode fingers protrudes in the direction in which the plurality of electrode fingers are arranged is set as the outer direction, and the direction in which the curved portion of the electrode fingers is recessed in the direction in which the plurality of electrode fingers are arranged is set as the inner direction. At this time, in at least one of the electrode fingers closest to the outer direction and the electrode fingers closest to the inner direction of at least two of the excitation angle change type resonators, the curvatures are different from each other.

7. The elastic wave device according to any one of claims 2 to 6, wherein: In at least two of the variable excitation angle resonators, the ranges of the excitation angles are different from each other.

8. The elastic wave device according to any one of claims 1 to 7, wherein: The plurality of electrode fingers in the IDT electrode of the variable excitation angle resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other. a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers as a first envelope, a virtual line formed by connecting the front ends of the plurality of first electrode fingers as a second envelope, and a region between the first envelope and the second envelope in the IDT electrode as a crossing region, A portion of the first electrode finger including a portion located on the first envelope and adjacent to the front end portion of any of the second electrode fingers is an adjacent portion of the first electrode finger, and a portion of the second electrode finger including a portion located on the second envelope and adjacent to the front end portion of any of the first electrode fingers is an adjacent portion of the second electrode finger. The structure in the intersection region of at least one of the excitation angle variable resonators is any one of the first structure to the third structure, The first structure is a structure in which the shapes of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view include circular arcs or elliptical arcs. The second structure is a structure in which the shapes of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view are curved, the curvatures of the first electrode fingers and the second electrode fingers are not constant, and the curvatures of the front end portions located on the first envelope side in at least one group of electrode fingers among the plurality of first electrode fingers and the plurality of second electrode fingers are different from each other, between the adjacent portions, or between the front end portion and the adjacent portion, The third structure is a structure including a plurality of parallel regions in which the plurality of first electrode fingers and the plurality of second electrode fingers extend in parallel, and non-parallel regions in which the directions in which the plurality of first electrode fingers and the plurality of second electrode fingers extend intersect with each other in the intersection region, and the parallel regions and the non-parallel regions are alternately arranged in at least a portion of the intersection region, and the plurality of first electrode fingers and the plurality of second electrode fingers extend linearly in the plurality of parallel regions and the non-parallel regions, respectively, and are bent at boundaries between the parallel regions and the non-parallel regions.

9. The elastic wave device according to claim 8, wherein: At least one of the excitation angle variable resonators has a pair of reflectors, the pair of reflectors are provided on the piezoelectric layer so as to face each other with the IDT electrode sandwiched therebetween, and each of the reflectors has a plurality of reflector electrode fingers. The structure in the intersection region of at least one of the variable excitation angle resonators is one of the first structure and the second structure, and the shapes of the plurality of reflector electrode fingers in a plan view include curved shapes.

10. The elastic wave device according to claim 8, wherein: At least one of the excitation angle variable resonators has a pair of reflectors, the pair of reflectors are provided on the piezoelectric layer so as to face each other with the IDT electrode sandwiched therebetween, and each of the reflectors has a plurality of reflector electrode fingers. The structure in the intersection region of at least one of the variable-excitation-angle resonators is the third structure, and the shapes of the plurality of reflector electrode fingers in a plan view include shapes bent at a plurality of nodes.

11. The elastic wave device according to any one of claims 8 to 10, wherein: At least two of the plurality of elastic wave resonators are the excitation angle-variable resonators, The structure in the intersection region of at least two of the excitation angle variable resonators is any one of the first to third structures that are different from each other.

12. The elastic wave device according to any one of claims 1 to 11, wherein: The plurality of electrode fingers in the IDT electrode of the variable excitation angle resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other. a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers as a first envelope, a virtual line formed by connecting the front ends of the plurality of first electrode fingers as a second envelope, and a region between the first envelope and the second envelope in the IDT electrode as a crossing region, The structure in which both the first envelope and the second envelope are in the shape of at least one bent portion with a change in extension direction is set as the fourth structure, the structure in which both the first envelope and the second envelope are straight lines and extend in parallel is set as the fifth structure, and the structure in which both the first envelope and the second envelope are straight lines and the extension direction of the first envelope intersects the extension direction of the second envelope is set as the sixth structure. At this time, the structure of the first envelope and the second envelope of at least one of the excitation angle variable resonators is any one of the fourth to sixth structures.

13. The elastic wave device according to claim 12, wherein: At least two of the plurality of elastic wave resonators are the excitation angle-variable resonators, The structures of the first envelope and the second envelope of at least two of the excitation angle variable resonators are any of the fourth to sixth structures that are different from each other.

14. The elastic wave device according to claim 12, wherein: In all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the fourth structure.

15. The elastic wave device according to claim 12, wherein: In all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the fifth structure.

16. The elastic wave device according to claim 12, wherein: In all of the variable excitation angle resonators, the structure of the first envelope and the second envelope is the sixth structure.

17. The elastic wave device according to any one of claims 1 to 16, wherein: All of the elastic wave resonators are excitation angle-variable resonators, In all of the variable excitation angle resonators, the shapes of the electrode fingers in a plan view are different from each other.

18. The elastic wave device according to any one of claims 1 to 16, wherein: At least one of the plurality of elastic wave resonators is not the excitation angle-variable resonator, The shape of the plurality of electrode fingers of the elastic wave resonator other than the excitation angle variable resonator in a plan view is a linear shape.

19. The elastic wave device according to claim 18, wherein: In the elastic wave resonator that is not the excitation angle variation type resonator, the piezoelectric layer has a propagation axis, and the plurality of electrode fingers in the IDT electrode of the elastic wave resonator include a plurality of third electrode fingers and a plurality of fourth electrode fingers that are interlaced with each other. A virtual line formed by connecting the front ends of the front ends of the plurality of fourth electrode fingers is set as the third envelope, and a virtual line formed by connecting the front ends of the front ends of the plurality of third electrode fingers is set as the fourth envelope. At this time, the third envelope and the fourth envelope are inclined relative to the propagation axis.

20. The elastic wave device according to any one of claims 1 to 19, wherein: In a portion of the IDT electrode of at least one of the variable excitation angle resonators where the excitation angle is the same, at least one of an electrode finger pitch and a duty ratio is constant.

21. The elastic wave device according to any one of claims 1 to 20, wherein: The plurality of electrode fingers in the IDT electrode of the variable excitation angle resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other. a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers as a first envelope, a virtual line formed by connecting the front ends of the plurality of first electrode fingers as a second envelope, and a region between the first envelope and the second envelope in the IDT electrode as a crossing region, In the intersection region of at least one of the excitation angle-variable resonators, the resonant frequency or the antiresonant frequency substantially matches.

22. The elastic wave device according to claim 21, wherein: At least two of the plurality of elastic wave resonators are the excitation angle-variable resonators, In each of the intersection regions of at least two of the excitation angle-variable resonators, the resonance frequencies are substantially the same. The following relationship holds true between at least two of the excitation angle variable resonators: when the resonant frequency of the portion in the intersection region where the excitation angle is 0° is set as a reference resonant frequency, a difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially consistent in the intersection region is less than or equal to 2% of the reference resonant frequency of any one of the two excitation angle variable resonators.

23. The elastic wave device according to claim 21, wherein: At least one of the plurality of elastic wave resonators is not the excitation angle-variable resonator, In the intersection region of at least one of the excitation angle-variable resonators, the resonance frequencies are substantially the same. In at least one of the excitation angle variable resonators and at least one of the elastic wave resonators that is not the excitation angle variable resonator, the following relationship holds: when the resonant frequency of the portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, the difference between the reference resonant frequency of the excitation angle variable resonator whose resonant frequencies are substantially consistent in the intersection region and the resonant frequency of the elastic wave resonator that is not the excitation angle variable resonator is less than 2% relative to either the reference resonant frequency or the resonant frequency.

24. The elastic wave device according to claim 21, wherein: At least two of the plurality of elastic wave resonators are the excitation angle-variable resonators, In each of the intersection regions of at least two of the excitation angle-variable resonators, the resonance frequencies are substantially the same. The following relationship holds true between at least two of the excitation angle variable resonators: when the resonant frequency of the portion in the intersection region where the excitation angle is 0° is set as a reference resonant frequency, a difference between the reference resonant frequencies of the two excitation angle variable resonators whose resonant frequencies are substantially consistent in the intersection region is greater than 2% relative to the reference resonant frequency of any one of the two excitation angle variable resonators.

25. The elastic wave device according to claim 21, wherein At least one of the plurality of elastic wave resonators is not the excitation angle-variable resonator, In the intersection region of at least one of the excitation angle-variable resonators, the resonance frequencies are substantially the same. In at least one of the excitation angle-varying resonators and at least one of the elastic wave resonators that is not the excitation angle-varying resonator, the following relationship holds: when the resonant frequency of the portion of the intersection region where the excitation angle is 0° is set as a reference resonant frequency, a difference between the reference resonant frequency of the excitation angle-varying resonator whose resonant frequencies are substantially consistent in the intersection region and the resonant frequency of the elastic wave resonator that is not the excitation angle-varying resonator is greater than 2% relative to either the reference resonant frequency or the resonant frequency.

26. The elastic wave device according to any one of claims 1 to 25, wherein: The plurality of electrode fingers in the IDT electrode of the variable excitation angle resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interlaced with each other. a virtual line formed by connecting the front ends of the front ends of the plurality of second electrode fingers as a first envelope, a virtual line formed by connecting the front ends of the plurality of first electrode fingers as a second envelope, and a region between the first envelope and the second envelope in the IDT electrode as a crossing region, The intersection region includes a first edge region including the first envelope, a second edge region including the second envelope, and a central region sandwiched by the first edge region and the second edge region. In at least one of the variable excitation angle resonators, at least a portion of at least one of the first edge region and the second edge region forms a low sound velocity region having a sound velocity lower than that in the central region.

27. The elastic wave device according to claim 26, wherein: In at least one of the first edge region and the second edge region, at least one of the electrode fingers has a wide portion having a width greater than that in the central region, thereby constituting the low acoustic velocity region.

28. The elastic wave device according to claim 26 or 27, wherein: At least one of the first edge region and the second edge region further includes a mass adding film, the mass adding film being provided so as to overlap with at least one of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view. The mass addition film is provided to form the low sound velocity region.

29. The elastic wave device according to any one of claims 26 to 28, wherein: In at least one of the first edge region and the second edge region, the thickness of at least one of the electrode fingers is thicker than that in the central region, thereby constituting the low acoustic velocity region.

30. The elastic wave device according to any one of claims 26 to 29, wherein: The low sound velocity region is formed in the entirety of both the first edge region and the second edge region.

31. The elastic wave device according to any one of claims 1 to 30, wherein: The piezoelectric substrate has a supporting substrate. The piezoelectric layer is provided on the supporting substrate.

32. The elastic wave device according to claim 31, wherein: The piezoelectric substrate includes an intermediate layer provided between the supporting substrate and the piezoelectric layer.

33. The elastic wave device according to claim 32, wherein: A hollow portion is formed in the piezoelectric substrate, and a portion of the support substrate and a portion of the piezoelectric layer face each other with the hollow portion interposed therebetween.

34. The elastic wave device according to any one of claims 1 to 30, wherein: The piezoelectric substrate includes only the piezoelectric layer.

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