WO2018117059A1 - Acoustic wave resonator, filter device, and multiplexer - Google Patents

Acoustic wave resonator, filter device, and multiplexer Download PDF

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Publication number
WO2018117059A1
WO2018117059A1 PCT/JP2017/045401 JP2017045401W WO2018117059A1 WO 2018117059 A1 WO2018117059 A1 WO 2018117059A1 JP 2017045401 W JP2017045401 W JP 2017045401W WO 2018117059 A1 WO2018117059 A1 WO 2018117059A1
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Prior art keywords
reflector
bus bar
comb
electrode
idt electrode
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PCT/JP2017/045401
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French (fr)
Japanese (ja)
Inventor
明雄 金田
普一 中村
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株式会社村田製作所
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Publication of WO2018117059A1 publication Critical patent/WO2018117059A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/64—Filters using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H03H9/72—Networks using surface acoustic waves

Definitions

  • the present invention relates to an elastic wave resonator having an IDT (InterDigital Transducer) electrode and a reflector, and a filter device and a multiplexer including the elastic wave resonator.
  • IDT InterDigital Transducer
  • a filter device composed of a plurality of acoustic wave resonators has been put into practical use for a band-pass filter or the like disposed in a front end portion of a mobile communication device.
  • FIG. 4 of Patent Document 1 includes two IDT electrodes arranged in parallel so as to have the same acoustic wave propagation direction, and an acoustic wave propagation direction.
  • An acoustic wave resonator is disclosed that includes one reflector disposed between two IDT electrodes and a plurality of reflectors disposed outside the two IDT electrodes.
  • one reflector disposed between two IDT electrodes is shared by the two IDT electrodes, thereby downsizing the acoustic wave resonator.
  • the present invention has been made to solve the above-described problems, and an object thereof is to provide an elastic wave resonator or the like having a small insertion loss and excellent steepness.
  • an acoustic wave resonator is an IDT electrode having a piezoelectric substrate and a pair of comb-like electrodes facing each other, and is provided on the piezoelectric substrate.
  • a first IDT electrode and a second IDT electrode disposed along a predetermined direction; and a shared reflector provided on the piezoelectric substrate and disposed between the first IDT electrode and the second IDT electrode in the predetermined direction.
  • the shared reflector has one reflector bus bar and the other reflector bus bar extending in the predetermined direction and facing each other in a direction orthogonal to the predetermined direction, and each of the first IDT electrode and the second IDT electrode Has one comb tooth bus bar and the other comb tooth bus bar extending in the predetermined direction and facing each other in the orthogonal direction, and the other comb tooth bar of the first IDT electrode. And a bar, and the other reflector busbar of the common reflector, and the other comb busbar of the first 2IDT electrode is disposed along the predetermined direction, are connected.
  • the first IDT electrode and the second IDT electrode are connected by using the other comb-tooth busbar of the first IDT electrode, the other reflector busbar, and the other comb-tooth busbar of the second IDT electrode.
  • the voltage applied to each of the 1 IDT electrode and the second IDT electrode can be reduced.
  • the first IDT electrode and the second IDT electrode are connected using the other comb-shaped bus bar, the other reflector bus bar, and the other comb-shaped bus bar described above, the first IDT electrode and the second IDT electrode are connected to each other.
  • the electrical resistance for connection can be reduced. Thereby, the insertion loss of the acoustic wave resonator can be reduced.
  • the other comb-tooth bus bar of the first IDT electrode and the other reflector bus bar of the shared reflector are a first connection located between the other comb-tooth bus bar and the other reflector bus bar.
  • the second reflector bus bar and the other comb bus bar of the second IDT electrode, which are connected via an electrode, are located between the other reflector bus bar and the other comb bus bar. It may be connected via an electrode.
  • a first input / output wiring is connected to the one comb tooth bus bar of the first IDT electrode
  • a second input / output wiring is connected to the one comb tooth bus bar of the second IDT electrode
  • the first input / output wiring is connected.
  • the first IDT electrode and the second IDT electrode may be connected in series in a path connecting the first input / output wiring and the second input / output wiring.
  • the electrical resistance can be reduced while connecting the first IDT electrode and the second IDT electrode in series in the path connecting the first input / output wiring and the second input / output wiring.
  • the insertion loss of the acoustic wave resonator can be reduced.
  • a second reflector provided on the opposite side of the shared reflector as viewed from the second IDT electrode in a direction, each of the first reflector and the second reflector extending in the predetermined direction and One reflector bus bar and the other reflector bus bar facing each other in the orthogonal direction, and the other reflector bus bar of the first reflector and the other comb-tooth bus bar of the first IDT electrode are the predetermined Arranged along the direction and connected to each other, and / or the other comb bus bar of the second IDT electrode and the other reflector bus bar of the second reflector Are arranged along the direction, they may be connected to each other.
  • one reflector bus bar of the first reflector and one comb tooth bus bar of the first IDT electrode face each other with different potentials, so that capacitance is added to the acoustic wave resonator.
  • one comb-shaped bus bar of the second IDT electrode and one reflector bus bar of the second reflector face each other with different potentials, capacitance is added to the acoustic wave resonator.
  • the steepness in the passband of the acoustic wave resonator can be improved.
  • a counter electrode may be provided, and the first counter electrode may be connected to a ground.
  • an insulating layer is provided on the one reflector bus bar of the shared reflector and on the one comb-shaped bus bar of each of the first IDT electrode and the second IDT electrode, and on the insulating layer
  • a second counter electrode facing the one reflector bus bar and the one comb-tooth bus bar may be provided, and the second counter electrode may be connected to the ground.
  • a filter device is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators At least one of the parallel arm resonators may include the elastic wave resonator described above.
  • the filter device by configuring the filter device with an acoustic wave resonator having a small insertion loss, the insertion loss in the pass band of the filter device can be reduced.
  • the steepness in the pass band of the filter device can be improved.
  • a filter device is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators May include the elastic wave resonator.
  • the insertion loss in the pass band of the filter device can be reduced by configuring the series arm resonator of the filter device with an acoustic wave resonator having a small insertion loss.
  • the IDT electrodes of the acoustic wave resonator are divided into two and connected in series, even if a large voltage is applied to the series arm resonator, the applied voltage is applied to the two IDT electrodes ( Since the first IDT electrode and the second IDT electrode can be dispersed, deterioration of electrical characteristics can be suppressed.
  • the steepness in the pass band of the filter device can be improved.
  • a multiplexer may include the above filter device.
  • the insertion loss in the pass band of the multiplexer can be reduced.
  • the insertion loss of the acoustic wave resonator can be reduced. Further, the insertion loss in the pass band of the filter device and the multiplexer can be reduced.
  • FIG. 1 is a circuit configuration diagram of a multiplexer and a filter device using the acoustic wave resonator according to the first embodiment.
  • 2A and 2B are diagrams illustrating the acoustic wave resonator according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG.
  • FIG. 3 is an equivalent circuit of the acoustic wave resonator according to the first embodiment.
  • FIG. 4 is a plan view showing an acoustic wave resonator in a comparative example.
  • FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example.
  • FIG. 6 is a diagram illustrating the insertion loss of the multiplexer in the first embodiment and the comparative example.
  • FIG. 7 is a plan view illustrating an acoustic wave resonator according to the second embodiment.
  • FIG. 8 is an equivalent circuit of the acoustic wave resonator according to the second embodiment.
  • FIG. 9 is a diagram showing insertion loss of the acoustic wave resonator in the second embodiment and the comparative example.
  • FIG. 10 is a diagram illustrating the insertion loss of the filter device in the second embodiment and the comparative example.
  • FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss and (b) is a diagram illustrating an isolation characteristic.
  • FIG. 12 is a plan view illustrating an acoustic wave resonator according to the third embodiment.
  • FIG. 13 is an equivalent circuit of the acoustic wave resonator according to the third embodiment.
  • 14A and 14B are diagrams illustrating an acoustic wave resonator according to the fourth embodiment, in which FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG.
  • FIG. 15 is an equivalent circuit of the acoustic wave resonator according to the fourth embodiment.
  • the multiplexer and filter device according to the present embodiment are used for communication devices such as mobile phones.
  • a duplexer of Band 5 transmission pass band: 824 to 849 MHz, reception pass band: 869 to 894 MHz
  • transmission pass band: 824 to 849 MHz reception pass band: 869 to 894 MHz
  • FIG. 1 is a circuit configuration diagram of the multiplexer 1 according to the first embodiment.
  • the multiplexer 1 includes a transmission filter 7 that is one filter device, a reception filter 8 that is the other filter device, an input / output terminal 6a on the antenna side, and an input / output terminal on the transmitter side. 6b and an input / output terminal 6c on the receiver side.
  • the transmission filter 7 and the reception filter 8 are connected to the input / output terminal 6a on the antenna side by bundling respective lead wires.
  • the transmission filter 7 is a band pass filter that filters the transmission wave input from the input / output terminal 6b on the transmitter side in each transmission pass band and outputs it to the input / output terminal 6a on the antenna side.
  • the reception filter 8 is a band pass filter that filters the received wave input from the input / output terminal 6a on the antenna side in each reception pass band and outputs it to the input / output terminal 6c on the receiver side.
  • the transmission filter 7 is a ladder-type filter, and series arm resonators 2a, 2b, 2c, 2d provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6b on the transmitter side, and Parallel arm resonators 3a, 3b, and 3c are connected between a connection path from the series arm resonator 2a to the series arm resonator 2d and a reference terminal (ground).
  • the reception filter 8 includes a series resonator 4 and a longitudinally coupled acoustic wave filter unit 5 provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6c on the receiver side.
  • the elastic wave resonator 10 is included in the series arm resonator 2b of the transmission filter 7, for example.
  • the acoustic wave resonator 10 may be included in at least one of the series arm resonators 2 a to 2 d in the transmission filter 7 or in the series resonator 4 in the reception filter 8.
  • the elastic wave resonator 10 may be included in the parallel arm resonators 3 a to 3 d of the transmission filter 7 or may be included in the resonators 5 a and 5 b of the longitudinally coupled elastic wave filter unit 5. .
  • the configuration of the acoustic wave resonator 10 will be described.
  • FIG. 2A and 2B are diagrams illustrating the acoustic wave resonator 10 according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG. FIG. 3 is an equivalent circuit of the acoustic wave resonator 10.
  • the acoustic wave resonator 10 is sometimes referred to as a piezoelectric substrate 90, and a first IDT electrode 11 and a second IDT electrode 22 (hereinafter referred to as IDT electrode 11 and IDT electrode 22) provided on the piezoelectric substrate 90.
  • the piezoelectric substrate 90 is made of, for example, LiTaO 3 piezoelectric single crystal, LiNbO 3 piezoelectric single crystal, or piezoelectric ceramic having a predetermined cut angle.
  • the cross-sectional structures of the IDT electrodes 11 and 22, the shared reflector 30, the first reflector 31, and the second reflector 32 will be described.
  • the IDT electrodes 11 and 22 have a laminated structure of an adhesion layer 91 and a main electrode layer 92 provided on the adhesion layer 91.
  • the first reflector 31, the shared reflector 30, and the second reflector 32 have a laminated structure of the adhesion layer 91 and the main electrode layer 92, similarly to the IDT electrodes 11 and 22.
  • the adhesion layer 91 is a layer for improving the adhesion between the piezoelectric substrate 90 and the main electrode layer 92, and, for example, Ti is used as a material.
  • the film thickness of the adhesion layer 91 is, for example, 12 nm.
  • the main electrode layer 92 is made of, for example, Al containing 1% Cu.
  • the film thickness of the main electrode layer 92 is, for example, 162 nm.
  • the protective layer 93 is formed so as to cover the IDT electrodes 11 and 22.
  • the protective layer 93 is a layer for the purpose of protecting the main electrode layer 92 from the external environment, adjusting frequency temperature characteristics, and improving moisture resistance, for example, a film containing silicon dioxide as a main component. .
  • a first input / output wiring 41, a second input / output wiring 42, a first connection electrode 51, and a second connection electrode 52 are provided on the piezoelectric substrate 90.
  • the IDT electrodes 11 and 22 are arranged along a predetermined direction D1.
  • the IDT electrode 11 is composed of a pair of comb-like electrodes 11a and 11b facing each other.
  • the IDT electrode 22 is composed of a pair of comb-like electrodes 22a and 22b facing each other.
  • the predetermined direction D1 in the present embodiment is the same direction as the elastic wave propagation direction.
  • the predetermined direction D1 is not limited to the same direction as the elastic wave propagation direction, and may be a direction slightly inclined with respect to the elastic wave propagation direction.
  • the plus side of the orthogonal direction D2 orthogonal to the predetermined direction D1 is referred to as one and the minus side of the orthogonal direction D2 is referred to as the other.
  • One comb-shaped electrode 11a of the IDT electrode 11 includes one comb-shaped bus bar 15a extending in a predetermined direction D1, a cross electrode finger 16 and an offset electrode connected to the comb-shaped bus bar 15a and extending in the orthogonal direction D2 (minus side). And a finger 17.
  • the other comb-shaped electrode 11b of the IDT electrode 11 includes the other comb-shaped bus bar 15b extending in the predetermined direction D1, the cross electrode finger 16 connected to the comb-shaped bus bar 15b and extending in the orthogonal direction D2 (plus side) and the offset electrode. And a finger 17.
  • One comb-shaped electrode 22a of the IDT electrode 22 includes one comb-shaped bus bar 25a extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25a and extending in the orthogonal direction D2 (minus side), and an offset electrode.
  • the other comb-shaped electrode 22b of the IDT electrode 22 includes the other comb-shaped bus bar 25b extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25b and extending in the orthogonal direction D2 (plus side), and an offset electrode. Finger 27.
  • the cross electrode fingers 16 and 26 cross each other as seen from the predetermined direction D1.
  • the offset electrode fingers 17 are shorter than the cross electrode fingers 16 and are disposed so as to face the cross electrode fingers 16 in the orthogonal direction D2.
  • the offset electrode finger 27 is shorter than the cross electrode finger 26 and is disposed to face the cross electrode finger 26 in the orthogonal direction D2.
  • the wavelength of the acoustic wave resonator 10 is defined by the repetition pitch ⁇ of the cross electrode fingers 16 and 26 in the predetermined direction D1.
  • One comb-shaped bus bar 15a, 25a and the other comb-shaped bus bar 15b, 25b are wider than the cross electrode fingers 16, 26 and the offset electrode fingers 17, 27 in order to reduce the electric resistance, and the thickness is also large. It is formed to be thick.
  • the first input / output wiring 41 is connected to one comb-tooth bus bar 15 a of the IDT electrode 11, and the second input / output wiring 42 is connected to one comb-tooth bus bar 25 a of the IDT electrode 22.
  • the common reflector 30 is disposed between the IDT electrode 11 and the IDT electrode 22 in the predetermined direction D1.
  • the shared reflector 30 is one reflector that is commonly used by the IDT electrodes 11 and 22.
  • the shared reflector 30 has one reflector bus bar 30a, the other reflector bus bar 30b, and a plurality of reflective electrode fingers 30c.
  • Each of the reflector bus bars 30a and 30b is disposed so as to extend in a predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 30c is connected to each of the reflector bus bars 30a and 30b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 30c are arranged to be parallel to each other at a predetermined interval in the predetermined direction D1.
  • the first reflector 31 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 11 in the predetermined direction D1.
  • the first reflector 31 has one reflector bus bar 31a, the other reflector bus bar 31b, and a plurality of reflective electrode fingers 31c.
  • Each of the reflector bus bars 31a and 31b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 31c is connected to the reflector bus bars 31a and 31b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 31c are arranged in parallel to each other at a predetermined interval in the predetermined direction D1.
  • the second reflector 32 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 22 in the predetermined direction D1.
  • the second reflector 32 has one reflector bus bar 32a, the other reflector bus bar 32b, and a plurality of reflective electrode fingers 32c.
  • Each of the reflector bus bars 32a and 32b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 32c is connected to the reflector bus bars 32a and 32b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 32c are arranged to be parallel to each other with a predetermined interval in the predetermined direction D1.
  • the reflector bus bars 30a, 30b, 31a, 31b, 32a, and 32b are formed to be wider and thicker than the reflective electrode fingers 30c, 31c, and 32c in order to reduce electrical resistance. .
  • the other comb-shaped bus bar 15b, the other reflector bus bar 30b, and the other comb-shaped bus bar 25b are arranged and connected along the predetermined direction D1.
  • a first connection electrode 51 is provided between the other comb bus bar 15b and the other reflector bus bar 30b, and between the other reflector bus bar 30b and the other comb bus bar 25b.
  • the second connection electrode 52 is provided.
  • the first connection electrode 51 connects the comb bus bar 15b and the reflector bus bar 30b
  • the second connection electrode 52 connects the reflector bus bar 30b and the comb bus bar 25b.
  • connection electrodes 51 and 52 are the same as the widths of the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b.
  • the thicknesses of the connection electrodes 51 and 52 are comb-tooth bus bars 15b and 25b and the reflector bus bar, respectively. It is the same as the thickness of 30b. That is, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, and the comb-tooth bus bar 25b are integrally formed linearly along the predetermined direction D1.
  • the connection electrodes 51 and 52 are formed by the same process (for example, lift-off method) as the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b, and have the same laminated structure.
  • the acoustic wave resonator 10 includes the IDT electrode 11 and the IDT electrode 22 in the path connecting the first input / output wiring 41 and the second input / output wiring 42, the first connection electrode 51, the reflector bus bar 30 b,
  • the second connection electrode 52 is connected in series. Since the IDT electrodes 11 and 22 are connected in series, the voltage applied to each of the IDT electrodes 11 and 22 can be reduced. Further, the IDT electrodes 11 and 22 are wider than the electrode fingers 16, 17, 26, and 27, and the comb bus bar 15 b, the first connection electrode 51, the reflector bus bar 30 b, the second connection electrode 52, and the comb are thick. Since it connects using the tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be made small. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • the acoustic wave resonator 10 has capacitors C1 and C2 corresponding to the respective acoustic wave elements F1 and F2 formed of the IDT electrodes 11 and 22 (see FIG. 3).
  • the capacitor C1 includes one comb-shaped bus bar 15a and one reflector bus bar 30a, which are located on the opposite side of the comb-shaped bus bar 15b and the reflector bus bar 30b connected by the first connection electrode 51. They are formed by facing each other with different potentials.
  • one reflector bus bar 30a and one comb bus bar 25a which are located on opposite sides of the reflector bus bar 30b and the comb bus bar 25b connected by the second connection electrode 52, face each other with different potentials. Is formed.
  • the acoustic wave resonator 10 has the capacitors C1 and C2, the steepness in the pass band of the acoustic wave resonator 10 can be improved.
  • the acoustic wave resonator 10 includes a piezoelectric substrate 90, an IDT electrode 11 having a pair of comb-like electrodes 11a and 11b facing each other, and an IDT having a pair of comb-like electrodes 22a and 22b.
  • the electrode 22 is provided on the piezoelectric substrate 90 and disposed along the predetermined direction D1, and the IDT electrode 11 and the IDT electrode 22 are provided on the piezoelectric substrate 90, and the IDT electrode 11 and the IDT electrode in the predetermined direction D1. 22 and a common reflector 30 disposed between them.
  • the shared reflector 30 has one reflector bus bar 30a and the other reflector bus bar 30b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2 of the predetermined direction D1.
  • the IDT electrode 11 has one comb-tooth bus bar 15a and the other comb-tooth bus bar 15b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the IDT electrode 22 has one comb-tooth bus bar 25a and the other comb-tooth bus bar 25b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the other comb-tooth bus bar 15b of the IDT electrode 11, the other reflector bus bar 30b, and the other comb-tooth bus bar 25b of the IDT electrode 22 are arranged and connected along a predetermined direction D1.
  • the IDT electrodes 11 and 22 are connected in series using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the voltage applied to the IDT electrodes 11 and 22 can be reduced. Can do. Moreover, since the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be reduced. . Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • the acoustic wave resonator 510 in the comparative example will be described as an example.
  • FIG. 4 is a plan view showing an acoustic wave resonator 510 in a comparative example.
  • the second connection electrode 52 connects one reflector bus bar 30a and one comb-tooth bus bar 25a, and the second input / output wiring 42 is connected to the other comb-tooth bus bar 25b. This is different from the elastic wave resonator 10 of the first embodiment.
  • the IDT electrode 11 and the IDT electrode 22 are connected in series via the reflective electrode fingers 30 c of the shared reflector 30.
  • the IDT electrodes 11 and 22 include the other comb-shaped bus bar 15b, the first connection electrode 51, the other reflector bus bar 30b, the reflection electrode finger 30c, the one reflector bus bar 30a, the second connection electrode 52, and the like. Are connected through one comb-tooth bus bar 25a.
  • the width and thickness of the reflective electrode finger 30c are smaller than the width and thickness of the comb-tooth bus bars 15b and 25b and the reflector bus bars 30a and 30b.
  • FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 10 of the present embodiment.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 of the comparative example.
  • the insertion loss in the passband of the filter device of the comparative example is 0.92 dB, whereas the insertion loss in the passband of the filter device of Embodiment 1 is 0.
  • the insertion loss is smaller than that of the comparative example.
  • FIG. 6 is a diagram showing the insertion loss of the multiplexer in the first embodiment and the comparative example.
  • the insertion loss in the transmission passband of the multiplexer of the comparative example is 0.94 dB
  • the insertion loss in the transmission passband of the multiplexer 1 of the first embodiment is The insertion loss is 0.92 dB, which is smaller than that of the comparative example.
  • the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, and therefore the IDT electrodes 11 and 22 are connected. Therefore, the electrical resistance can be reduced. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • Embodiment 2 Next, an acoustic wave resonator 10A according to Embodiment 2 will be described. Note that the multiplexer and filter device of the second embodiment have the same circuit configuration as that of the first embodiment, and therefore the description thereof is omitted.
  • FIG. 7 is a plan view showing an acoustic wave resonator 10A according to the second embodiment.
  • FIG. 8 is an equivalent circuit of the acoustic wave resonator 10A.
  • This elastic wave resonator 10A is further provided with a third connection electrode 53 and a fourth connection electrode 54 in addition to the elastic wave resonator 10 of the first embodiment.
  • a third connection electrode 53 is provided between the other reflector bus bar 31b and the other comb bus bar 15b, and between the other comb bus bar 25b and the other reflector bus bar 32b, A fourth connection electrode 54 is provided.
  • the third connection electrode 53 connects the reflector bus bar 31b and the comb bus bar 15b
  • the fourth connection electrode 54 connects the comb bus bar 25b and the reflector bus bar 32b.
  • the reflector bus bar 31b, the connection electrode 53, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, the comb-tooth bus bar 25b, the connection electrode 54, and the reflector bus bar 32b have the same width and thickness, It is integrally formed linearly along the predetermined direction D1.
  • the acoustic wave resonator 10A has capacitors C3 and C4 corresponding to the respective acoustic wave elements F1 and F2 constituted by the IDT electrodes 11 and 22 (see FIG. 8).
  • the capacitor C3 has one comb-shaped bus bar 15a and one reflector bus bar 30a facing each other at different potentials, and one reflector bus bar located on the opposite side of the connected bus bar. 31a and one comb-shaped bus bar 15a are formed by facing each other with different potentials.
  • the capacitor C4 is located on the opposite side of the connected bus bar so that one reflector bus bar 30a and the one comb bus bar 25a face each other with different potentials, and one comb bus bar 25a and one comb bus bar 25a It is formed by facing the reflector bus bar 32a with a different potential.
  • the acoustic wave resonator 10 since the acoustic wave resonator 10 includes the capacitors C3 and C4, the steepness in the passband of the acoustic wave resonator 10A can be improved.
  • FIG. 9 is a diagram showing the insertion loss of the acoustic wave resonator in the second embodiment and the comparative example.
  • the increase value of the insertion loss of the elastic wave resonator 510 of the comparative example is 5.62 dB
  • the elasticity of the second embodiment is The increase value of the insertion loss of the wave resonator 10A is 5.92 dB, which is higher than the comparative example.
  • FIG. 10 is a diagram showing the insertion loss of the filter device in the second embodiment and the comparative example.
  • the series arm resonator 2b shown in FIG. 1 includes the acoustic wave resonator 10A of the present embodiment.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 (see FIG. 4) of the comparative example.
  • the increase value of the insertion loss in the passband of the filter device of the comparative example is 27 ⁇ 05 dB, whereas the filter of the second embodiment The increase value of the insertion loss in the pass band of the device is 29.24 dB, which is higher than the comparative example.
  • FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss, and (b) is a diagram illustrating an isolation characteristic.
  • the isolation characteristic was obtained by measuring the insertion loss between Tx and Rx in the multiplexer shown in FIG.
  • the increase value of the insertion loss in the transmission passband of the multiplexer of the comparative example is 27.18 dB.
  • the increase value of the insertion loss in the transmission pass band of the multiplexer 1 of the form 2 is 29.13 dB, which is higher than the comparative example.
  • the second embodiment has a frequency difference ⁇ f between the frequency f ⁇ 1 having a Tx loss of 2 dB and the frequency f ⁇ 2 having an Rx band Iso of 50 dB as compared with the comparative example. .Improved (smaller) by 3 MHz and improved isolation.
  • the other reflector bus bar 31b of the first reflector 31 and the other comb of the IDT electrode 11 are combined.
  • the tooth bus bar 15b is disposed along the predetermined direction D1 and connected to each other.
  • the other comb-tooth bus bar 25b of the IDT electrode 22 and the other reflector bus bar 32b of the second reflector 32 are arranged along the predetermined direction D1 and connected to each other.
  • the acoustic wave resonator 10A further has a capacity, steepness in the pass band of the acoustic wave resonator 10A can be improved.
  • the acoustic wave resonator 10A at least one of a state where the reflector bus bar 31b and the comb bus bar 15b are connected and a state where the comb bus bar 25b and the reflector bus bar 32b are connected is used. If it has, it has the said effect.
  • FIG. 12 is a plan view showing an acoustic wave resonator 10B according to the third embodiment.
  • FIG. 13 is an equivalent circuit of the acoustic wave resonator 10B.
  • This elastic wave resonator 10B is further provided with a first counter electrode 61 in addition to the elastic wave resonator 10 of the first embodiment.
  • the first counter electrode 61 facing the one reflector bus bar 30a is provided on the side opposite to the other reflector bus bar 30b when viewed from the one reflector bus bar 30a of the shared reflector 30.
  • the provided first counter electrode 61 is provided in parallel with a predetermined distance from the reflector bus bar 30a.
  • the first counter electrode 61 is connected to the ground.
  • the same material as the protective layer 93 (for example, silicon dioxide) mentioned above is filled between the reflector bus bar 30a and the first counter electrode 61.
  • the acoustic wave resonator 10B has a capacitor C5 in addition to the capacitors C1 and C2, as shown in FIG.
  • the capacitor C5 is formed by facing one reflector bus bar 30a and the first counter electrode 61 with different potentials.
  • the acoustic wave resonator 10B further includes the capacitor C5, the steepness in the pass band of the acoustic wave resonator 10B can be improved.
  • FIG. 14A and 14B are diagrams illustrating an acoustic wave resonator 10C according to the fourth embodiment, where FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG. 14A.
  • FIG. 15 is an equivalent circuit of the acoustic wave resonator 10C.
  • illustration of the adhesion layer 91, the main electrode layer 92, and the protective layer 93 is omitted.
  • This elastic wave resonator 10C is further provided with a second counter electrode 62 in addition to the elastic wave resonator 10 of the first embodiment.
  • an insulating layer 63 is provided on one reflector bus bar 30a of the shared reflector 30 and one comb-tooth bus bars 15a and 25a of the IDT electrodes 11 and 22, respectively.
  • a second counter electrode 62 is provided to face one reflector bus bar 30a and one comb-tooth bus bar 15a, 25a in the thickness direction.
  • the second counter electrode 62 extends along the predetermined direction D1, the negative end of the predetermined direction D1 is connected to one reflector bus bar 31a, and the positive end is connected to one reflector bus bar 32a. Has been.
  • the second counter electrode 62 is connected to the ground.
  • the material of the insulating layer 63 is appropriately selected from, for example, silicon dioxide and polyimide.
  • the acoustic wave resonator 10C has a capacitor C6 in addition to the capacitors C3 and C4 as shown in FIG.
  • the capacitor C6 is formed by the reflector bus bar 30a, the comb-tooth bus bars 15a and 25a, and the second counter electrode 62 facing each other across the insulating layer 63 and having different potentials.
  • the acoustic wave resonator 10C further includes the capacitor C6, the steepness in the pass band of the acoustic wave resonator 10C can be improved.
  • the acoustic wave resonators 10 to 10C are not limited to surface acoustic wave resonators, and may be boundary acoustic wave resonators.
  • the electrode fingers of the comb-shaped electrodes 11a, 11b, 22a, and 22b are not limited thereto, and may include the cross electrode fingers 16 and 26 without the offset electrode fingers 17 and 27.
  • the materials constituting the adhesion layer 91, the main electrode layer 92, and the protective layer 93 of the acoustic wave resonator 10 are not limited to the materials described above.
  • the IDT electrodes 11 and 22 do not have to have the above laminated structure.
  • the IDT electrodes 11 and 22 may be made of, for example, a metal or an alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd. It may be configured.
  • the protective layer 93 may not be formed.
  • the piezoelectric substrate 90 of the acoustic wave resonator 10 may have a laminated structure in which a high sound velocity supporting substrate, a low sound velocity film, and a piezoelectric film are laminated in this order.
  • the piezoelectric film may be, for example, a 50 ° Y-cut X-propagating LiTaO 3 piezoelectric single crystal or a piezoelectric ceramic (a lithium tantalate single crystal cut along a plane whose axis is rotated by 50 ° from the Y axis with the X axis as the central axis, Alternatively, it is made of ceramic and is made of a single crystal or ceramic in which surface acoustic waves propagate in the X-axis direction.
  • the piezoelectric film has a thickness of 600 nm, for example.
  • the high sound velocity support substrate is a substrate that supports the low sound velocity film, the piezoelectric film, and the IDT electrode.
  • the high-sonic support substrate is a substrate in which the acoustic velocity of the bulk wave in the high-sonic support substrate is higher than that of the surface wave or boundary wave that propagates through the piezoelectric film. It functions in such a way that it is confined in the portion where the sonic film is laminated and does not leak below the high sonic support substrate.
  • the high sound speed support substrate is, for example, a silicon substrate and has a thickness of, for example, 200 ⁇ m.
  • the low acoustic velocity film is a membrane in which the acoustic velocity of the bulk wave in the low acoustic velocity film is lower than the bulk wave propagating through the piezoelectric membrane, and is disposed between the piezoelectric membrane and the high acoustic velocity support substrate. Due to this structure and the property that energy is concentrated in a medium where acoustic waves are essentially low in sound velocity, leakage of surface acoustic wave energy to the outside of the IDT electrode is suppressed.
  • the low acoustic velocity film is, for example, a film mainly composed of silicon dioxide and has a thickness of, for example, 670 nm.
  • the Q value at the resonance frequency and the anti-resonance frequency can be significantly increased as compared with a structure in which the piezoelectric substrate 90 is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be configured, a filter with a small insertion loss can be configured using the surface acoustic wave resonator.
  • the predetermined direction D1 is the same direction as the elastic wave propagation direction.
  • the present invention is not limited thereto, and the predetermined direction D1 is a direction slightly inclined with respect to the elastic wave propagation direction.
  • each of the comb-tooth bus bars 15a, 15b, 25a, 25b and the reflector bus bars 30a, 30b, 31a, 31b, 32a, 32b in the first embodiment is 0 ° or more and 10 ° or less with respect to the elastic wave propagation direction. It may be formed extending in an inclined direction.
  • each of the crossed electrode fingers 16, 26, the offset electrode fingers 17, 27, and the reflective electrode fingers 30c, 31c, 32c may be formed so as to extend in a direction orthogonal to the elastic wave propagation direction.
  • the wavelength of the acoustic wave resonator 10 may be defined by the repetition pitch ⁇ of each of the cross electrode fingers 16 and 26 in the acoustic wave propagation direction.
  • the present invention can be widely used in mobile communication devices such as mobile phones as acoustic wave resonators, filter devices, duplexers, and multiplexers with low insertion loss.

Abstract

An acoustic wave resonator (10) that comprises: IDT electrodes (11, 22) that are arranged along a prescribed direction (D1); and a shared reflector (30) that is arranged between the IDT electrodes (11, 22) in the prescribed direction (D1). The shared reflector (30) has reflector busbars (30a, 30b) that face each other in a direction (D2) that is orthogonal to the prescribed direction (D1). IDT electrode (11) has comb busbars (15a, 15b) that face each other in the orthogonal direction (D2). IDT electrode (22) has comb busbars (25a, 25b) that face each other in the orthogonal direction (D2). Comb busbar (15b), reflector busbar (30b), and comb busbar (25b) are arranged along the prescribed direction (D1) and connected.

Description

弾性波共振器、フィルタ装置およびマルチプレクサElastic wave resonator, filter device, and multiplexer
　本発明は、ＩＤＴ（ＩｎｔｅｒＤｉｇｉｔａｌ　Ｔｒａｎｓｄｕｃｅｒ）電極と反射器とを有する弾性波共振器、および、この弾性波共振器を備えるフィルタ装置およびマルチプレクサに関する。 The present invention relates to an elastic wave resonator having an IDT (InterDigital Transducer) electrode and a reflector, and a filter device and a multiplexer including the elastic wave resonator.
　従来、移動体通信機のフロントエンド部に配置される帯域通過フィルタなどに、複数の弾性波共振器からなるフィルタ装置が実用化されている。 Conventionally, a filter device composed of a plurality of acoustic wave resonators has been put into practical use for a band-pass filter or the like disposed in a front end portion of a mobile communication device.
　この種の弾性波共振器の一例として、特許文献１の図４には、弾性波伝搬方向が互いに同じとなるように配置されて並列接続された２つのＩＤＴ電極と、弾性波伝搬方向において、２つのＩＤＴ電極の間に配置された１つの反射器と、２つのＩＤＴ電極よりも外側に配置された複数の反射器とを備える弾性波共振器が開示されている。 As an example of this type of acoustic wave resonator, FIG. 4 of Patent Document 1 includes two IDT electrodes arranged in parallel so as to have the same acoustic wave propagation direction, and an acoustic wave propagation direction. An acoustic wave resonator is disclosed that includes one reflector disposed between two IDT electrodes and a plurality of reflectors disposed outside the two IDT electrodes.
　この弾性波共振器では、２つのＩＤＴ電極の間に配置された１つの反射器を、２つのＩＤＴ電極にて共用することで、弾性波共振器を小型化している。 In this acoustic wave resonator, one reflector disposed between two IDT electrodes is shared by the two IDT electrodes, thereby downsizing the acoustic wave resonator.
特開２０１１－１３９５１３号公報JP 2011-139513 A
　しかしながら、特許文献１に開示された弾性波共振器では、２つのＩＤＴ電極が並列接続されているため、電力が分散されず、弾性波共振器に大きな電力が印加された場合に電気特性が劣化することがある。電力を分散する方法として、２つのＩＤＴ電極を直列接続することも考えられるが、直列接続のしかたによっては、弾性波共振器の挿入損失が大きくなることがある。 However, in the elastic wave resonator disclosed in Patent Document 1, since two IDT electrodes are connected in parallel, electric power is not dispersed, and electrical characteristics deteriorate when large electric power is applied to the elastic wave resonator. There are things to do. As a method of distributing power, it is conceivable to connect two IDT electrodes in series. However, depending on the method of series connection, the insertion loss of the acoustic wave resonator may increase.
　そこで、本発明は、上記課題を解決するためになされたものであって、挿入損失が小さく、また、急峻性に優れた弾性波共振器等を提供することを目的とする。 Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide an elastic wave resonator or the like having a small insertion loss and excellent steepness.
　上記目的を達成するために、本発明の一態様に係る弾性波共振器は、圧電基板と、互いに対向する一対の櫛歯状電極を有するＩＤＴ電極であって、前記圧電基板上に設けられ、所定方向に沿って配置された第１ＩＤＴ電極および第２ＩＤＴ電極と、前記圧電基板上に設けられ、前記所定方向において前記第１ＩＤＴ電極と前記第２ＩＤＴ電極との間に配置された共用反射器とを備え、前記共用反射器は、前記所定方向に延びて前記所定方向の直交方向に互いに対向する一方の反射器バスバーおよび他方の反射器バスバーを有し、前記第１ＩＤＴ電極および前記第２ＩＤＴ電極のそれぞれは、前記所定方向に延びて前記直交方向に互いに対向する一方の櫛歯バスバーおよび他方の櫛歯バスバーを有し、前記第１ＩＤＴ電極の前記他方の櫛歯バスバーと、前記共用反射器の前記他方の反射器バスバーと、前記第２ＩＤＴ電極の前記他方の櫛歯バスバーとが、前記所定方向に沿って配置され、接続されている。 To achieve the above object, an acoustic wave resonator according to an aspect of the present invention is an IDT electrode having a piezoelectric substrate and a pair of comb-like electrodes facing each other, and is provided on the piezoelectric substrate. A first IDT electrode and a second IDT electrode disposed along a predetermined direction; and a shared reflector provided on the piezoelectric substrate and disposed between the first IDT electrode and the second IDT electrode in the predetermined direction. The shared reflector has one reflector bus bar and the other reflector bus bar extending in the predetermined direction and facing each other in a direction orthogonal to the predetermined direction, and each of the first IDT electrode and the second IDT electrode Has one comb tooth bus bar and the other comb tooth bus bar extending in the predetermined direction and facing each other in the orthogonal direction, and the other comb tooth bar of the first IDT electrode. And a bar, and the other reflector busbar of the common reflector, and the other comb busbar of the first 2IDT electrode is disposed along the predetermined direction, are connected.
　このように、第１ＩＤＴ電極と第２ＩＤＴ電極とを、第１ＩＤＴ電極の他方の櫛歯バスバー、他方の反射器バスバー、および、第２ＩＤＴ電極の他方の櫛歯バスバーを用いて接続することで、第１ＩＤＴ電極および第２ＩＤＴ電極のそれぞれにかかる電圧を小さくすることができる。また、第１ＩＤＴ電極と第２ＩＤＴ電極とが、上記に示す他方の櫛歯バスバー、他方の反射器バスバーおよび他方の櫛歯バスバーを用いて接続されているので、第１ＩＤＴ電極と第２ＩＤＴ電極とを接続するための電気抵抗を小さくすることができる。これにより、弾性波共振器の挿入損失を小さくすることができる。 In this way, the first IDT electrode and the second IDT electrode are connected by using the other comb-tooth busbar of the first IDT electrode, the other reflector busbar, and the other comb-tooth busbar of the second IDT electrode. The voltage applied to each of the 1 IDT electrode and the second IDT electrode can be reduced. In addition, since the first IDT electrode and the second IDT electrode are connected using the other comb-shaped bus bar, the other reflector bus bar, and the other comb-shaped bus bar described above, the first IDT electrode and the second IDT electrode are connected to each other. The electrical resistance for connection can be reduced. Thereby, the insertion loss of the acoustic wave resonator can be reduced.
　また、前記第１ＩＤＴ電極の前記他方の櫛歯バスバーと前記共用反射器の前記他方の反射器バスバーとは、当該他方の櫛歯バスバーと前記他方の反射器バスバーとの間に位置する第１接続電極を介して接続され、前記他方の反射器バスバーと前記第２ＩＤＴ電極の前記他方の櫛歯バスバーとは、前記他方の反射器バスバーと当該他方の櫛歯バスバーとの間に位置する第２接続電極を介して接続されていてもよい。 The other comb-tooth bus bar of the first IDT electrode and the other reflector bus bar of the shared reflector are a first connection located between the other comb-tooth bus bar and the other reflector bus bar. The second reflector bus bar and the other comb bus bar of the second IDT electrode, which are connected via an electrode, are located between the other reflector bus bar and the other comb bus bar. It may be connected via an electrode.
　このように、第１接続電極および第２接続電極を介して上記に示す他方の櫛歯バスバー、他方の反射器バスバー、および他方の櫛歯バスバーを接続することで、隣り合うバスバーを短い距離で接続することができる。これにより、第１ＩＤＴ電極と第２ＩＤＴ電極とを接続するための電気抵抗を小さくすることができ、弾性波共振器の挿入損失を小さくすることができる。 Thus, by connecting the other comb-shaped bus bar, the other reflector bus bar, and the other comb-shaped bus bar shown above via the first connection electrode and the second connection electrode, adjacent bus bars can be connected at a short distance. Can be connected. Thereby, the electrical resistance for connecting the first IDT electrode and the second IDT electrode can be reduced, and the insertion loss of the acoustic wave resonator can be reduced.
　また、前記第１ＩＤＴ電極の前記一方の櫛歯バスバーに第１入出力配線が接続され、前記第２ＩＤＴ電極の前記一方の櫛歯バスバーに第２入出力配線が接続され、前記第１入出力配線と前記第２入出力配線とを結ぶ経路において、前記第１ＩＤＴ電極と前記第２ＩＤＴ電極とは直列接続されていてもよい。 Further, a first input / output wiring is connected to the one comb tooth bus bar of the first IDT electrode, a second input / output wiring is connected to the one comb tooth bus bar of the second IDT electrode, and the first input / output wiring is connected. The first IDT electrode and the second IDT electrode may be connected in series in a path connecting the first input / output wiring and the second input / output wiring.
　これによれば、第１入出力配線と第２入出力配線とを結ぶ経路において、第１ＩＤＴ電極と第２ＩＤＴ電極とを直列接続しつつ、電気抵抗を小さくすることができる。これにより、弾性波共振器の挿入損失を小さくすることができる。 According to this, the electrical resistance can be reduced while connecting the first IDT electrode and the second IDT electrode in series in the path connecting the first input / output wiring and the second input / output wiring. Thereby, the insertion loss of the acoustic wave resonator can be reduced.
　また、さらに、前記圧電基板上に設けられ、前記所定方向において前記第１ＩＤＴ電極から見て前記共用反射器と反対側に設けられた第１反射器と、前記圧電基板上に設けられ、前記所定方向において前記第２ＩＤＴ電極から見て前記共用反射器と反対側に設けられた第２反射器とを備え、前記第１反射器および前記第２反射器のそれぞれは、前記所定方向に延びて前記直交方向に互いに対向する一方の反射器バスバーおよび他方の反射器バスバーを有し、前記第１反射器の前記他方の反射器バスバーと、前記第１ＩＤＴ電極の前記他方の櫛歯バスバーとが前記所定方向に沿って配置され、互いに接続されている、および／または、前記第２ＩＤＴ電極の前記他方の櫛歯バスバーと、前記第２反射器の前記他方の反射器バスバーとが前記所定方向に沿って配置され、互いに接続されていてもよい。 Furthermore, a first reflector provided on the piezoelectric substrate and provided on the opposite side of the shared reflector as viewed from the first IDT electrode in the predetermined direction, and provided on the piezoelectric substrate, the predetermined substrate A second reflector provided on the opposite side of the shared reflector as viewed from the second IDT electrode in a direction, each of the first reflector and the second reflector extending in the predetermined direction and One reflector bus bar and the other reflector bus bar facing each other in the orthogonal direction, and the other reflector bus bar of the first reflector and the other comb-tooth bus bar of the first IDT electrode are the predetermined Arranged along the direction and connected to each other, and / or the other comb bus bar of the second IDT electrode and the other reflector bus bar of the second reflector Are arranged along the direction, they may be connected to each other.
　この構成によれば、第１反射器の一方の反射器バスバーと第１ＩＤＴ電極の一方の櫛歯バスバーとが、異なる電位をもって対向するので、弾性波共振器に容量が付加される。また、第２ＩＤＴ電極の一方の櫛歯バスバーと第２反射器の一方の反射器バスバーとが、異なる電位をもって対向するので、弾性波共振器に容量が付加される。このように、弾性波共振器に容量が付加されることで、弾性波共振器の通過帯域における急峻性を向上することができる。 According to this configuration, one reflector bus bar of the first reflector and one comb tooth bus bar of the first IDT electrode face each other with different potentials, so that capacitance is added to the acoustic wave resonator. In addition, since one comb-shaped bus bar of the second IDT electrode and one reflector bus bar of the second reflector face each other with different potentials, capacitance is added to the acoustic wave resonator. As described above, by adding the capacitance to the acoustic wave resonator, the steepness in the passband of the acoustic wave resonator can be improved.
　また、さらに、前記直交方向において、前記共用反射器の前記一方の反射器バスバーから見て前記共用反射器の前記他方の反射器バスバーと反対側に、当該一方の反射器バスバーと対向する第１対向電極が設けられ、前記第１対向電極は、グランドに接続されていてもよい。 Further, in the orthogonal direction, the first reflector facing the one reflector bus bar on the side opposite to the other reflector bus bar of the shared reflector as viewed from the one reflector bus bar of the shared reflector. A counter electrode may be provided, and the first counter electrode may be connected to a ground.
　この構成によれば、共用反射器の一方の反射器バスバーと第１対向電極とが、異なる電位をもって対向するので、弾性波共振器に容量が付加される。これにより、弾性波共振器の通過帯域における急峻性を向上することができる。 According to this configuration, since one reflector bus bar of the shared reflector and the first counter electrode face each other with different potentials, capacitance is added to the acoustic wave resonator. Thereby, the steepness in the pass band of the acoustic wave resonator can be improved.
　また、さらに、前記共用反射器の前記一方の反射器バスバー上、および、前記第１ＩＤＴ電極および前記第２ＩＤＴ電極のそれぞれの前記一方の櫛歯バスバー上に、絶縁層が設けられ、前記絶縁層上に、当該一方の反射器バスバーおよび当該一方の櫛歯バスバーと対向する第２対向電極が設けられ、前記第２対向電極は、グランドに接続されていてもよい。 Furthermore, an insulating layer is provided on the one reflector bus bar of the shared reflector and on the one comb-shaped bus bar of each of the first IDT electrode and the second IDT electrode, and on the insulating layer In addition, a second counter electrode facing the one reflector bus bar and the one comb-tooth bus bar may be provided, and the second counter electrode may be connected to the ground.
　この構成によれば、上記一方の反射器バスバーおよび上記一方の櫛歯バスバーと、第２対向電極とが、異なる電位をもって対向するので、弾性波共振器に容量が付加される。これにより、弾性波共振器の通過帯域における急峻性を向上することができる。 According to this configuration, since the one reflector bus bar and the one comb tooth bus bar and the second counter electrode face each other with different potentials, a capacitance is added to the acoustic wave resonator. Thereby, the steepness in the pass band of the acoustic wave resonator can be improved.
　また、本発明の一態様に係るフィルタ装置は、１または複数の直列腕共振子、および、１または複数の並列腕共振子によって構成されるラダー型のフィルタ装置であって、前記直列腕共振子および前記並列腕共振子の少なくとも１つは、上記記載の弾性波共振器を含んでいてもよい。 A filter device according to an aspect of the present invention is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators At least one of the parallel arm resonators may include the elastic wave resonator described above.
　このように、挿入損失が小さい弾性波共振器でフィルタ装置を構成することで、フィルタ装置の通過帯域における挿入損失を小さくすることができる。また、上記構成によって弾性波共振器に容量を付加した場合には、フィルタ装置の通過帯域における急峻性を向上することができる。 Thus, by configuring the filter device with an acoustic wave resonator having a small insertion loss, the insertion loss in the pass band of the filter device can be reduced. In addition, when a capacitance is added to the acoustic wave resonator with the above configuration, the steepness in the pass band of the filter device can be improved.
　また、本発明の一態様に係るフィルタ装置は、１または複数の直列腕共振子、および、１または複数の並列腕共振子によって構成されるラダー型のフィルタ装置であって、前記直列腕共振子は、上記弾性波共振器を含んでいてもよい。 A filter device according to an aspect of the present invention is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators May include the elastic wave resonator.
　このように、挿入損失が小さい弾性波共振器でフィルタ装置の直列腕共振子を構成することで、フィルタ装置の通過帯域における挿入損失を小さくすることができる。また、弾性波共振器のＩＤＴ電極を２つに分けて直列に接続しているので、直列腕共振子に大きな電圧が印加された場合であっても、印加された電圧を２つのＩＤＴ電極（第１ＩＤＴ電極および第２ＩＤＴ電極）に分散することができるので、電気特性の劣化を抑制することができる。また、上記構成によって弾性波共振器に容量を付加した場合には、フィルタ装置の通過帯域における急峻性を向上することができる。 Thus, the insertion loss in the pass band of the filter device can be reduced by configuring the series arm resonator of the filter device with an acoustic wave resonator having a small insertion loss. In addition, since the IDT electrodes of the acoustic wave resonator are divided into two and connected in series, even if a large voltage is applied to the series arm resonator, the applied voltage is applied to the two IDT electrodes ( Since the first IDT electrode and the second IDT electrode can be dispersed, deterioration of electrical characteristics can be suppressed. In addition, when a capacitance is added to the acoustic wave resonator with the above configuration, the steepness in the pass band of the filter device can be improved.
　また、本発明の一態様に係るマルチプレクサは、上記フィルタ装置を含んでいてもよい。 Further, a multiplexer according to one embodiment of the present invention may include the above filter device.
　これによれば、マルチプレクサの通過帯域における挿入損失を小さくすることができる。 According to this, the insertion loss in the pass band of the multiplexer can be reduced.
　本発明によれば、弾性波共振器の挿入損失を小さくすることができる。また、フィルタ装置およびマルチプレクサの通過帯域における挿入損失を小さくすることができる。 According to the present invention, the insertion loss of the acoustic wave resonator can be reduced. Further, the insertion loss in the pass band of the filter device and the multiplexer can be reduced.
図１は、実施の形態１に係る弾性波共振器を用いたマルチプレクサおよびフィルタ装置の回路構成図である。FIG. 1 is a circuit configuration diagram of a multiplexer and a filter device using the acoustic wave resonator according to the first embodiment. 図２は、実施の形態１に係る弾性波共振器を表す図であって、（ａ）は平面図、（ｂ）は（ａ）に示すＩＩＢ－ＩＩＢ線の断面図である。2A and 2B are diagrams illustrating the acoustic wave resonator according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG. 図３は、実施の形態１に係る弾性波共振器の等価回路である。FIG. 3 is an equivalent circuit of the acoustic wave resonator according to the first embodiment. 図４は、比較例における弾性波共振器を表す平面図である。FIG. 4 is a plan view showing an acoustic wave resonator in a comparative example. 図５は、実施の形態１および比較例におけるフィルタ装置の挿入損失を示す図である。FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example. 図６は、実施の形態１および比較例におけるマルチプレクサの挿入損失を示す図である。FIG. 6 is a diagram illustrating the insertion loss of the multiplexer in the first embodiment and the comparative example. 図７は、実施の形態２に係る弾性波共振器を表す平面図である。FIG. 7 is a plan view illustrating an acoustic wave resonator according to the second embodiment. 図８は、実施の形態２に係る弾性波共振器の等価回路である。FIG. 8 is an equivalent circuit of the acoustic wave resonator according to the second embodiment. 図９は、実施の形態２および比較例における弾性波共振器の挿入損失を示す図である。FIG. 9 is a diagram showing insertion loss of the acoustic wave resonator in the second embodiment and the comparative example. 図１０は、実施の形態２および比較例におけるフィルタ装置の挿入損失を示す図である。FIG. 10 is a diagram illustrating the insertion loss of the filter device in the second embodiment and the comparative example. 図１１は、実施の形態２および比較例におけるマルチプレクサの周波数特性を示す図であって、（ａ）は挿入損失、（ｂ）はアイソレーション特性を示す図である。FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss and (b) is a diagram illustrating an isolation characteristic. 図１２は、実施の形態３に係る弾性波共振器を表す平面図である。FIG. 12 is a plan view illustrating an acoustic wave resonator according to the third embodiment. 図１３は、実施の形態３に係る弾性波共振器の等価回路である。FIG. 13 is an equivalent circuit of the acoustic wave resonator according to the third embodiment. 図１４は、実施の形態４に係る弾性波共振器を表す図であって、（ａ）は平面図、（ｂ）は（ａ）に示すＸＩＶＢ－ＸＩＶＢ線の断面図である。14A and 14B are diagrams illustrating an acoustic wave resonator according to the fourth embodiment, in which FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG. 図１５は、実施の形態４に係る弾性波共振器の等価回路である。FIG. 15 is an equivalent circuit of the acoustic wave resonator according to the fourth embodiment.
　（実施の形態１）
　以下、本発明の実施の形態について、図面を用いて詳細に説明する。なお、以下で説明する実施の形態およびその変形例は、いずれも包括的または具体的な例を示すものである。以下の実施の形態およびその変形例で示される数値、形状、材料、構成要素、構成要素の配置および接続形態などは、一例であり、本発明を限定する主旨ではない。以下の実施の形態およびその変形例における構成要素のうち、独立請求項に記載されていない構成要素については、任意の構成要素として説明される。また、図面に示される構成要素の大きさ、または大きさの比は、必ずしも厳密ではない。 (Embodiment 1)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments and modifications thereof described below is a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement of constituent elements, and connection forms shown in the following embodiments and modifications thereof are merely examples, and are not intended to limit the present invention. Among the constituent elements in the following embodiments and modifications thereof, constituent elements not described in the independent claims are described as arbitrary constituent elements. Further, the size of components shown in the drawings or the ratio of sizes is not necessarily strict.
　［１－１．マルチプレクサおよびフィルタ装置の回路構成］
　本実施の形態に係るマルチプレクサおよびフィルタ装置は、携帯電話などの通信機器に利用される。本実施の形態では、マルチプレクサとして、Ｂａｎｄ５（送信通過帯域：８２４～８４９ＭＨｚ、受信通過帯域：８６９～８９４ＭＨｚ）のデュプレクサを例に挙げて説明する。 [1-1. Circuit configuration of multiplexer and filter device]
The multiplexer and filter device according to the present embodiment are used for communication devices such as mobile phones. In the present embodiment, a duplexer of Band 5 (transmission pass band: 824 to 849 MHz, reception pass band: 869 to 894 MHz) will be described as an example of a multiplexer.
　図１は、実施の形態１に係るマルチプレクサ１の回路構成図である。 FIG. 1 is a circuit configuration diagram of the multiplexer 1 according to the first embodiment.
　マルチプレクサ１は、図１に示すように、一方のフィルタ装置である送信フィルタ７と、もう一方のフィルタ装置である受信フィルタ８と、アンテナ側の入出力端子６ａと、送信機側の入出力端子６ｂと、受信機側の入出力端子６ｃとを備える。送信フィルタ７および受信フィルタ８は、それぞれの引き出し線が束ねられてアンテナ側の入出力端子６ａに接続されている。 As shown in FIG. 1, the multiplexer 1 includes a transmission filter 7 that is one filter device, a reception filter 8 that is the other filter device, an input / output terminal 6a on the antenna side, and an input / output terminal on the transmitter side. 6b and an input / output terminal 6c on the receiver side. The transmission filter 7 and the reception filter 8 are connected to the input / output terminal 6a on the antenna side by bundling respective lead wires.
　送信フィルタ７は、送信機側の入出力端子６ｂから入力された送信波を、各送信通過帯域でフィルタリングしてアンテナ側の入出力端子６ａへ出力する帯域通過フィルタである。受信フィルタ８は、アンテナ側の入出力端子６ａから入力された受信波を、各受信通過帯域でフィルタリングして受信機側の入出力端子６ｃへ出力する帯域通過フィルタである。 The transmission filter 7 is a band pass filter that filters the transmission wave input from the input / output terminal 6b on the transmitter side in each transmission pass band and outputs it to the input / output terminal 6a on the antenna side. The reception filter 8 is a band pass filter that filters the received wave input from the input / output terminal 6a on the antenna side in each reception pass band and outputs it to the input / output terminal 6c on the receiver side.
　送信フィルタ７は、ラダー型フィルタであり、アンテナ側の入出力端子６ａと送信機側の入出力端子６ｂとを結ぶ経路上に設けられた直列腕共振子２ａ、２ｂ、２ｃ、２ｄ、および、直列腕共振子２ａから直列腕共振子２ｄまでの接続経路と基準端子（グランド）との間に接続された並列腕共振子３ａ、３ｂ、３ｃを有する。受信フィルタ８は、アンテナ側の入出力端子６ａと受信機側の入出力端子６ｃとを結ぶ経路上に設けられた直列共振子４および縦結合型弾性波フィルタ部５を有する。 The transmission filter 7 is a ladder-type filter, and series arm resonators 2a, 2b, 2c, 2d provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6b on the transmitter side, and Parallel arm resonators 3a, 3b, and 3c are connected between a connection path from the series arm resonator 2a to the series arm resonator 2d and a reference terminal (ground). The reception filter 8 includes a series resonator 4 and a longitudinally coupled acoustic wave filter unit 5 provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6c on the receiver side.
　本実施の形態に係る弾性波共振器１０は、例えば、送信フィルタ７の直列腕共振子２ｂに含まれる。なお、弾性波共振器１０は、送信フィルタ７における直列腕共振子２ａ～２ｄの少なくとも１つ、または、受信フィルタ８における直列共振子４に含まれていてもよい。また、弾性波共振器１０は、送信フィルタ７の並列腕共振子３ａ～３ｄに含まれていてもよいし、縦結合型弾性波フィルタ部５の共振子５ａ、５ｂに含まれていてもよい。以下、弾性波共振器１０の構成について説明する。 The elastic wave resonator 10 according to the present embodiment is included in the series arm resonator 2b of the transmission filter 7, for example. The acoustic wave resonator 10 may be included in at least one of the series arm resonators 2 a to 2 d in the transmission filter 7 or in the series resonator 4 in the reception filter 8. The elastic wave resonator 10 may be included in the parallel arm resonators 3 a to 3 d of the transmission filter 7 or may be included in the resonators 5 a and 5 b of the longitudinally coupled elastic wave filter unit 5. . Hereinafter, the configuration of the acoustic wave resonator 10 will be described.
　［１－２．弾性波共振器の構成］
　図２は、実施の形態１に係る弾性波共振器１０を表す図であって、（ａ）は平面図、（ｂ）は（ａ）に示すＩＩＢ－ＩＩＢ線の断面図である。図３は、弾性波共振器１０の等価回路である。 [1-2. Configuration of elastic wave resonator]
2A and 2B are diagrams illustrating the acoustic wave resonator 10 according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG. FIG. 3 is an equivalent circuit of the acoustic wave resonator 10.
　弾性波共振器１０は、図２に示すように、圧電基板９０と、圧電基板９０上に設けられた第１ＩＤＴ電極１１および第２ＩＤＴ電極２２（以下、ＩＤＴ電極１１、ＩＤＴ電極２２と呼ぶ場合がある）と、圧電基板９０上に設けられた共用反射器３０、第１反射器３１および第２反射器３２とを備えている。 As shown in FIG. 2, the acoustic wave resonator 10 is sometimes referred to as a piezoelectric substrate 90, and a first IDT electrode 11 and a second IDT electrode 22 (hereinafter referred to as IDT electrode 11 and IDT electrode 22) provided on the piezoelectric substrate 90. A common reflector 30, a first reflector 31, and a second reflector 32 provided on the piezoelectric substrate 90.
　圧電基板９０は、例えば、所定のカット角を有するＬｉＴａＯ３圧電単結晶、ＬｉＮｂＯ３圧電単結晶、または圧電セラミックスからなる。 The piezoelectric substrate 90 is made of, for example, LiTaO 3 piezoelectric single crystal, LiNbO 3 piezoelectric single crystal, or piezoelectric ceramic having a predetermined cut angle.
　先に、ＩＤＴ電極１１、２２、共用反射器３０、第１反射器３１および第２反射器３２の断面構造について説明する。ＩＤＴ電極１１、２２は、図２の（ｂ）に示すように、密着層９１と、密着層９１上に設けられた主電極層９２との積層構造となっている。また、第１反射器３１、共用反射器３０および第２反射器３２は、ＩＤＴ電極１１、２２と同様に密着層９１と主電極層９２との積層構造となっている。 First, the cross-sectional structures of the IDT electrodes 11 and 22, the shared reflector 30, the first reflector 31, and the second reflector 32 will be described. As shown in FIG. 2B, the IDT electrodes 11 and 22 have a laminated structure of an adhesion layer 91 and a main electrode layer 92 provided on the adhesion layer 91. Further, the first reflector 31, the shared reflector 30, and the second reflector 32 have a laminated structure of the adhesion layer 91 and the main electrode layer 92, similarly to the IDT electrodes 11 and 22.
　密着層９１は、圧電基板９０と主電極層９２との密着性を向上させるための層であり、材料として、例えば、Ｔｉが用いられる。密着層９１の膜厚は、例えば、１２ｎｍである。主電極層９２は、材料として、例えば、Ｃｕを１％含有したＡｌが用いられる。主電極層９２の膜厚は、例えば１６２ｎｍである。保護層９３は、ＩＤＴ電極１１、２２を覆うように形成されている。保護層９３は、主電極層９２を外部環境から保護する、周波数温度特性を調整する、および、耐湿性を高めるなどを目的とする層であり、例えば、二酸化ケイ素を主成分とする膜である。 The adhesion layer 91 is a layer for improving the adhesion between the piezoelectric substrate 90 and the main electrode layer 92, and, for example, Ti is used as a material. The film thickness of the adhesion layer 91 is, for example, 12 nm. The main electrode layer 92 is made of, for example, Al containing 1% Cu. The film thickness of the main electrode layer 92 is, for example, 162 nm. The protective layer 93 is formed so as to cover the IDT electrodes 11 and 22. The protective layer 93 is a layer for the purpose of protecting the main electrode layer 92 from the external environment, adjusting frequency temperature characteristics, and improving moisture resistance, for example, a film containing silicon dioxide as a main component. .
　次に、図２の（ａ）を参照しつつ、圧電基板９０上におけるＩＤＴ電極１１、２２、共用反射器３０、第１反射器３１および第２反射器３２の配置について説明する。なお、圧電基板９０上には、上記の他に第１入出力配線４１、第２入出力配線４２、第１接続電極５１および第２接続電極５２が設けられている。 Next, the arrangement of the IDT electrodes 11 and 22, the shared reflector 30, the first reflector 31, and the second reflector 32 on the piezoelectric substrate 90 will be described with reference to FIG. In addition to the above, a first input / output wiring 41, a second input / output wiring 42, a first connection electrode 51, and a second connection electrode 52 are provided on the piezoelectric substrate 90.
　ＩＤＴ電極１１、２２は、所定方向Ｄ１に沿って配置されている。ＩＤＴ電極１１は、互いに対向する一対の櫛歯状電極１１ａおよび１１ｂにより構成されている。ＩＤＴ電極２２は、互いに対向する一対の櫛歯状電極２２ａおよび２２ｂにより構成されている。本実施の形態における所定方向Ｄ１は、弾性波伝搬方向と同じ方向である。なお、所定方向Ｄ１は、弾性波伝搬方向と同じ方向に限られず、弾性波伝搬方向に対して多少傾いた方向であってもよい。 IDT electrodes 11 and 22 are arranged along a predetermined direction D1. The IDT electrode 11 is composed of a pair of comb- like electrodes 11a and 11b facing each other. The IDT electrode 22 is composed of a pair of comb- like electrodes 22a and 22b facing each other. The predetermined direction D1 in the present embodiment is the same direction as the elastic wave propagation direction. The predetermined direction D1 is not limited to the same direction as the elastic wave propagation direction, and may be a direction slightly inclined with respect to the elastic wave propagation direction.
　以下、図２の（ａ）において、ＩＤＴ電極１１、２２のそれぞれの中心位置を基準として、所定方向Ｄ１に直交する直交方向Ｄ２のプラス側を一方、直交方向Ｄ２のマイナス側を他方と呼ぶことにする。 Hereinafter, in FIG. 2A, with reference to the center positions of the IDT electrodes 11 and 22, the plus side of the orthogonal direction D2 orthogonal to the predetermined direction D1 is referred to as one and the minus side of the orthogonal direction D2 is referred to as the other. To.
　ＩＤＴ電極１１の一方の櫛歯状電極１１ａは、所定方向Ｄ１に延びる一方の櫛歯バスバー１５ａと、櫛歯バスバー１５ａに接続されて直交方向Ｄ２（マイナス側）に延びる交差電極指１６およびオフセット電極指１７と、を有している。ＩＤＴ電極１１の他方の櫛歯状電極１１ｂは、所定方向Ｄ１に延びる他方の櫛歯バスバー１５ｂと、櫛歯バスバー１５ｂに接続されて直交方向Ｄ２（プラス側）に延びる交差電極指１６およびオフセット電極指１７と、を有している。 One comb-shaped electrode 11a of the IDT electrode 11 includes one comb-shaped bus bar 15a extending in a predetermined direction D1, a cross electrode finger 16 and an offset electrode connected to the comb-shaped bus bar 15a and extending in the orthogonal direction D2 (minus side). And a finger 17. The other comb-shaped electrode 11b of the IDT electrode 11 includes the other comb-shaped bus bar 15b extending in the predetermined direction D1, the cross electrode finger 16 connected to the comb-shaped bus bar 15b and extending in the orthogonal direction D2 (plus side) and the offset electrode. And a finger 17.
　ＩＤＴ電極２２の一方の櫛歯状電極２２ａは、所定方向Ｄ１に延びる一方の櫛歯バスバー２５ａと、櫛歯バスバー２５ａに接続されて直交方向Ｄ２（マイナス側）に延びる交差電極指２６およびオフセット電極指２７と、を有している。ＩＤＴ電極２２の他方の櫛歯状電極２２ｂは、所定方向Ｄ１に延びる他方の櫛歯バスバー２５ｂと、櫛歯バスバー２５ｂに接続されて直交方向Ｄ２（プラス側）に延びる交差電極指２６およびオフセット電極指２７と、を有している。 One comb-shaped electrode 22a of the IDT electrode 22 includes one comb-shaped bus bar 25a extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25a and extending in the orthogonal direction D2 (minus side), and an offset electrode. Finger 27. The other comb-shaped electrode 22b of the IDT electrode 22 includes the other comb-shaped bus bar 25b extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25b and extending in the orthogonal direction D2 (plus side), and an offset electrode. Finger 27.
　交差電極指１６、２６は、所定方向Ｄ１から見て、互いに交差している。オフセット電極指１７は、交差電極指１６よりも長さが短く、交差電極指１６に対して直交方向Ｄ２に対向して配置されている。オフセット電極指２７は、交差電極指２６よりも長さが短く、交差電極指２６に対して直交方向Ｄ２に対向して配置されている。弾性波共振器１０の波長は、所定方向Ｄ１における交差電極指１６、２６の繰り返しピッチλで規定される。 The cross electrode fingers 16 and 26 cross each other as seen from the predetermined direction D1. The offset electrode fingers 17 are shorter than the cross electrode fingers 16 and are disposed so as to face the cross electrode fingers 16 in the orthogonal direction D2. The offset electrode finger 27 is shorter than the cross electrode finger 26 and is disposed to face the cross electrode finger 26 in the orthogonal direction D2. The wavelength of the acoustic wave resonator 10 is defined by the repetition pitch λ of the cross electrode fingers 16 and 26 in the predetermined direction D1.
　一方の櫛歯バスバー１５ａ、２５ａおよび他方の櫛歯バスバー１５ｂ、２５ｂは、電気抵抗を小さくするため、交差電極指１６、２６およびオフセット電極指１７、２７よりも幅が広く、また、厚さが厚くなるように形成されている。ＩＤＴ電極１１の一方の櫛歯バスバー１５ａには第１入出力配線４１が接続され、ＩＤＴ電極２２の一方の櫛歯バスバー２５ａには、第２入出力配線４２が接続されている。 One comb-shaped bus bar 15a, 25a and the other comb-shaped bus bar 15b, 25b are wider than the cross electrode fingers 16, 26 and the offset electrode fingers 17, 27 in order to reduce the electric resistance, and the thickness is also large. It is formed to be thick. The first input / output wiring 41 is connected to one comb-tooth bus bar 15 a of the IDT electrode 11, and the second input / output wiring 42 is connected to one comb-tooth bus bar 25 a of the IDT electrode 22.
　共用反射器３０は、所定方向Ｄ１において、ＩＤＴ電極１１とＩＤＴ電極２２との間に配置されている。共用反射器３０は、ＩＤＴ電極１１、２２で共通して使用される１つの反射器である。 The common reflector 30 is disposed between the IDT electrode 11 and the IDT electrode 22 in the predetermined direction D1. The shared reflector 30 is one reflector that is commonly used by the IDT electrodes 11 and 22.
　共用反射器３０は、一方の反射器バスバー３０ａと、他方の反射器バスバー３０ｂと、複数の反射電極指３０ｃとを有している。反射器バスバー３０ａ、３０ｂのそれぞれは、所定方向Ｄ１に延び、直交方向Ｄ２に互いに対向するように配置されている。複数の反射電極指３０ｃのそれぞれは、反射器バスバー３０ａ、３０ｂのそれぞれに接続され、直交方向Ｄ２に延びるように配置されている。また、複数の反射電極指３０ｃは、所定方向Ｄ１に所定間隔をあけて、互いに平行となるように配置されている。 The shared reflector 30 has one reflector bus bar 30a, the other reflector bus bar 30b, and a plurality of reflective electrode fingers 30c. Each of the reflector bus bars 30a and 30b is disposed so as to extend in a predetermined direction D1 and to face each other in the orthogonal direction D2. Each of the plurality of reflective electrode fingers 30c is connected to each of the reflector bus bars 30a and 30b and arranged to extend in the orthogonal direction D2. The plurality of reflective electrode fingers 30c are arranged to be parallel to each other at a predetermined interval in the predetermined direction D1.
　第１反射器３１は、所定方向Ｄ１においてＩＤＴ電極１１から見て共用反射器３０と反対側に設けられている。第１反射器３１は、一方の反射器バスバー３１ａ、他方の反射器バスバー３１ｂおよび複数の反射電極指３１ｃを有している。反射器バスバー３１ａ、３１ｂのそれぞれは、所定方向Ｄ１に延びて直交方向Ｄ２に互いに対向するように配置されている。複数の反射電極指３１ｃのそれぞれは、反射器バスバー３１ａ、３１ｂに接続され、直交方向Ｄ２に延びるように配置されている。また、複数の反射電極指３１ｃは、所定方向Ｄ１に所定間隔をあけて、互いに平行となるように配置されている。 The first reflector 31 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 11 in the predetermined direction D1. The first reflector 31 has one reflector bus bar 31a, the other reflector bus bar 31b, and a plurality of reflective electrode fingers 31c. Each of the reflector bus bars 31a and 31b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2. Each of the plurality of reflective electrode fingers 31c is connected to the reflector bus bars 31a and 31b and arranged to extend in the orthogonal direction D2. The plurality of reflective electrode fingers 31c are arranged in parallel to each other at a predetermined interval in the predetermined direction D1.
　第２反射器３２は、所定方向Ｄ１においてＩＤＴ電極２２から見て共用反射器３０と反対側に設けられている。第２反射器３２は、一方の反射器バスバー３２ａと、他方の反射器バスバー３２ｂと、複数の反射電極指３２ｃとを有している。反射器バスバー３２ａ、３２ｂのそれぞれは、所定方向Ｄ１に延びて直交方向Ｄ２に互いに対向するように配置されている。複数の反射電極指３２ｃのそれぞれは、反射器バスバー３２ａ、３２ｂに接続され、直交方向Ｄ２に延びるように配置されている。また、複数の反射電極指３２ｃは、所定方向Ｄ１に所定間隔をあけて、互いに平行となるように配置されている。 The second reflector 32 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 22 in the predetermined direction D1. The second reflector 32 has one reflector bus bar 32a, the other reflector bus bar 32b, and a plurality of reflective electrode fingers 32c. Each of the reflector bus bars 32a and 32b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2. Each of the plurality of reflective electrode fingers 32c is connected to the reflector bus bars 32a and 32b and arranged to extend in the orthogonal direction D2. The plurality of reflective electrode fingers 32c are arranged to be parallel to each other with a predetermined interval in the predetermined direction D1.
　反射器バスバー３０ａ、３０ｂ、３１ａ、３１ｂ、３２ａ、３２ｂは、電気抵抗を小さくするため、反射電極指３０ｃ、３１ｃ、３２ｃよりも幅が広く、また、厚さが厚くなるように形成されている。例えば、（反射器バスバー３０ｂの断面積）＞（反射電極指３０ｃの断面積×反射電極指３０ｃの本数）である。 The reflector bus bars 30a, 30b, 31a, 31b, 32a, and 32b are formed to be wider and thicker than the reflective electrode fingers 30c, 31c, and 32c in order to reduce electrical resistance. . For example, (the cross-sectional area of the reflector bus bar 30b)> (the cross-sectional area of the reflective electrode fingers 30c × the number of the reflective electrode fingers 30c).
　本実施の形態では、他方の櫛歯バスバー１５ｂと、他方の反射器バスバー３０ｂと、他方の櫛歯バスバー２５ｂとが、所定方向Ｄ１に沿って配置され、接続されている。具体的には、他方の櫛歯バスバー１５ｂと他方の反射器バスバー３０ｂとの間には、第１接続電極５１が設けられ、他方の反射器バスバー３０ｂと他方の櫛歯バスバー２５ｂとの間には、第２接続電極５２が設けられている。そして、第１接続電極５１は、櫛歯バスバー１５ｂと反射器バスバー３０ｂとを接続し、第２接続電極５２は、反射器バスバー３０ｂと櫛歯バスバー２５ｂとを接続している。 In the present embodiment, the other comb-shaped bus bar 15b, the other reflector bus bar 30b, and the other comb-shaped bus bar 25b are arranged and connected along the predetermined direction D1. Specifically, a first connection electrode 51 is provided between the other comb bus bar 15b and the other reflector bus bar 30b, and between the other reflector bus bar 30b and the other comb bus bar 25b. The second connection electrode 52 is provided. The first connection electrode 51 connects the comb bus bar 15b and the reflector bus bar 30b, and the second connection electrode 52 connects the reflector bus bar 30b and the comb bus bar 25b.
　接続電極５１、５２のそれぞれの幅は、櫛歯バスバー１５ｂ、２５ｂ、反射器バスバー３０ｂの幅と同じであり、接続電極５１、５２のそれぞれの厚みは、櫛歯バスバー１５ｂ、２５ｂ、反射器バスバー３０ｂの厚みと同じである。すなわち、櫛歯バスバー１５ｂ、接続電極５１、反射器バスバー３０ｂ、接続電極５２および櫛歯バスバー２５ｂは、所定方向Ｄ１に沿って直線状に一体となって形成されている。接続電極５１、５２は、櫛歯バスバー１５ｂ、２５ｂおよび反射器バスバー３０ｂと同一プロセス（例えばリフトオフ法など）により形成され、同じ積層構造を有している。 The widths of the connection electrodes 51 and 52 are the same as the widths of the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b. The thicknesses of the connection electrodes 51 and 52 are comb-tooth bus bars 15b and 25b and the reflector bus bar, respectively. It is the same as the thickness of 30b. That is, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, and the comb-tooth bus bar 25b are integrally formed linearly along the predetermined direction D1. The connection electrodes 51 and 52 are formed by the same process (for example, lift-off method) as the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b, and have the same laminated structure.
　これらにより、弾性波共振器１０は、第１入出力配線４１と第２入出力配線４２とを結ぶ経路において、ＩＤＴ電極１１とＩＤＴ電極２２とが、第１接続電極５１、反射器バスバー３０ｂ、第２接続電極５２を介して直列接続された構造となる。ＩＤＴ電極１１、２２が直列接続されることで、ＩＤＴ電極１１、２２のそれぞれにかかる電圧を小さくすることができる。また、ＩＤＴ電極１１、２２が、電極指１６、１７、２６、２７よりも幅が大きく、厚みが厚い櫛歯バスバー１５ｂ、第１接続電極５１、反射器バスバー３０ｂ、第２接続電極５２および櫛歯バスバー２５ｂを用いて接続されているので、ＩＤＴ電極１１、２２を接続するための電気抵抗を小さくすることができる。これにより、弾性波共振器１０の挿入損失を小さくすることができる。 Accordingly, the acoustic wave resonator 10 includes the IDT electrode 11 and the IDT electrode 22 in the path connecting the first input / output wiring 41 and the second input / output wiring 42, the first connection electrode 51, the reflector bus bar 30 b, The second connection electrode 52 is connected in series. Since the IDT electrodes 11 and 22 are connected in series, the voltage applied to each of the IDT electrodes 11 and 22 can be reduced. Further, the IDT electrodes 11 and 22 are wider than the electrode fingers 16, 17, 26, and 27, and the comb bus bar 15 b, the first connection electrode 51, the reflector bus bar 30 b, the second connection electrode 52, and the comb are thick. Since it connects using the tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be made small. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
　また、弾性波共振器１０は、ＩＤＴ電極１１、２２で構成されるそれぞれの弾性波素子Ｆ１、Ｆ２に対応して、容量Ｃ１、Ｃ２を有している（図３参照）。具体的には、容量Ｃ１は、第１接続電極５１で接続された櫛歯バスバー１５ｂおよび反射器バスバー３０ｂの反対側に位置する、一方の櫛歯バスバー１５ａと一方の反射器バスバー３０ａとが、異なる電位をもって対向することで形成される。容量Ｃ２は、第２接続電極５２で接続された反射器バスバー３０ｂおよび櫛歯バスバー２５ｂの反対側に位置する、一方の反射器バスバー３０ａと一方の櫛歯バスバー２５ａとが、異なる電位をもって対向することで形成される。このように、弾性波共振器１０が容量Ｃ１、Ｃ２を有することで、弾性波共振器１０の通過帯域における急峻性を向上することができる。 Further, the acoustic wave resonator 10 has capacitors C1 and C2 corresponding to the respective acoustic wave elements F1 and F2 formed of the IDT electrodes 11 and 22 (see FIG. 3). Specifically, the capacitor C1 includes one comb-shaped bus bar 15a and one reflector bus bar 30a, which are located on the opposite side of the comb-shaped bus bar 15b and the reflector bus bar 30b connected by the first connection electrode 51. They are formed by facing each other with different potentials. In the capacitor C2, one reflector bus bar 30a and one comb bus bar 25a, which are located on opposite sides of the reflector bus bar 30b and the comb bus bar 25b connected by the second connection electrode 52, face each other with different potentials. Is formed. As described above, since the acoustic wave resonator 10 has the capacitors C1 and C2, the steepness in the pass band of the acoustic wave resonator 10 can be improved.
　［１－３．効果等］
　本実施の形態に係る弾性波共振器１０は、圧電基板９０と、互いに対向する一対の櫛歯状電極１１ａ、１１ｂを有するＩＤＴ電極１１、および、一対の櫛歯状電極２２ａ、２２ｂを有するＩＤＴ電極２２であって、圧電基板９０上に設けられ、所定方向Ｄ１に沿って配置されたＩＤＴ電極１１およびＩＤＴ電極２２と、圧電基板９０上に設けられ、所定方向Ｄ１においてＩＤＴ電極１１とＩＤＴ電極２２との間に配置された共用反射器３０とを備えている。共用反射器３０は、所定方向Ｄ１に延びて所定方向Ｄ１の直交方向Ｄ２に互いに対向する一方の反射器バスバー３０ａおよび他方の反射器バスバー３０ｂを有している。ＩＤＴ電極１１は、所定方向Ｄ１に延びて直交方向Ｄ２に互いに対向する一方の櫛歯バスバー１５ａおよび他方の櫛歯バスバー１５ｂを有している。ＩＤＴ電極２２は、所定方向Ｄ１に延びて直交方向Ｄ２に互いに対向する一方の櫛歯バスバー２５ａおよび他方の櫛歯バスバー２５ｂを有している。ＩＤＴ電極１１の他方の櫛歯バスバー１５ｂ、他方の反射器バスバー３０ｂ、および、ＩＤＴ電極２２の他方の櫛歯バスバー２５ｂは、所定方向Ｄ１に沿って配置され、接続されている。 [1-3. Effect]
The acoustic wave resonator 10 according to the present embodiment includes a piezoelectric substrate 90, an IDT electrode 11 having a pair of comb- like electrodes 11a and 11b facing each other, and an IDT having a pair of comb- like electrodes 22a and 22b. The electrode 22 is provided on the piezoelectric substrate 90 and disposed along the predetermined direction D1, and the IDT electrode 11 and the IDT electrode 22 are provided on the piezoelectric substrate 90, and the IDT electrode 11 and the IDT electrode in the predetermined direction D1. 22 and a common reflector 30 disposed between them. The shared reflector 30 has one reflector bus bar 30a and the other reflector bus bar 30b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2 of the predetermined direction D1. The IDT electrode 11 has one comb-tooth bus bar 15a and the other comb-tooth bus bar 15b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2. The IDT electrode 22 has one comb-tooth bus bar 25a and the other comb-tooth bus bar 25b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2. The other comb-tooth bus bar 15b of the IDT electrode 11, the other reflector bus bar 30b, and the other comb-tooth bus bar 25b of the IDT electrode 22 are arranged and connected along a predetermined direction D1.
　この構成によれば、ＩＤＴ電極１１、２２が、櫛歯バスバー１５ｂ、反射器バスバー３０ｂおよび櫛歯バスバー２５ｂを用いて直列接続されるので、ＩＤＴ電極１１、２２のそれぞれにかかる電圧を小さくすることができる。また、ＩＤＴ電極１１、２２が、櫛歯バスバー１５ｂ、反射器バスバー３０ｂおよび櫛歯バスバー２５ｂを用いて接続されているので、ＩＤＴ電極１１、２２を接続するための電気抵抗を小さくすることができる。これにより、弾性波共振器１０の挿入損失を小さくすることができる。 According to this configuration, since the IDT electrodes 11 and 22 are connected in series using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the voltage applied to the IDT electrodes 11 and 22 can be reduced. Can do. Moreover, since the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be reduced. . Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
　ここで、本実施の形態に係る弾性波共振器１０の効果等を説明するため、比較例における弾性波共振器５１０を例に挙げて説明する。 Here, in order to explain the effects of the acoustic wave resonator 10 according to the present embodiment, the acoustic wave resonator 510 in the comparative example will be described as an example.
　図４は、比較例における弾性波共振器５１０を表す平面図である。 FIG. 4 is a plan view showing an acoustic wave resonator 510 in a comparative example.
　比較例の弾性波共振器５１０は、第２接続電極５２が一方の反射器バスバー３０ａと一方の櫛歯バスバー２５ａとを接続し、第２入出力配線４２が他方の櫛歯バスバー２５ｂに接続されている点で、実施の形態１の弾性波共振器１０と異なる。 In the acoustic wave resonator 510 of the comparative example, the second connection electrode 52 connects one reflector bus bar 30a and one comb-tooth bus bar 25a, and the second input / output wiring 42 is connected to the other comb-tooth bus bar 25b. This is different from the elastic wave resonator 10 of the first embodiment.
　弾性波共振器５１０では、ＩＤＴ電極１１とＩＤＴ電極２２とが、共用反射器３０の反射電極指３０ｃを介して直列接続されている。具体的には、ＩＤＴ電極１１、２２は、他方の櫛歯バスバー１５ｂ、第１接続電極５１、他方の反射器バスバー３０ｂ、反射電極指３０ｃ、一方の反射器バスバー３０ａ、第２接続電極５２および、一方の櫛歯バスバー２５ａを介して接続されている。反射電極指３０ｃの幅、厚みは、櫛歯バスバー１５ｂ、２５ｂおよび反射器バスバー３０ａ、３０ｂの幅、厚みに比べて小さい。例えば、（反射電極指３０ｃの断面積×反射電極指３０ｃの本数）＜（反射器バスバー３０ｂの断面積）である。そのため、比較例における弾性波共振器５１０では、ＩＤＴ電極１１、２２を接続するための電気抵抗が大きくなり、弾性波共振器５１０の挿入損失を小さくすることが困難である。 In the acoustic wave resonator 510, the IDT electrode 11 and the IDT electrode 22 are connected in series via the reflective electrode fingers 30 c of the shared reflector 30. Specifically, the IDT electrodes 11 and 22 include the other comb-shaped bus bar 15b, the first connection electrode 51, the other reflector bus bar 30b, the reflection electrode finger 30c, the one reflector bus bar 30a, the second connection electrode 52, and the like. Are connected through one comb-tooth bus bar 25a. The width and thickness of the reflective electrode finger 30c are smaller than the width and thickness of the comb-tooth bus bars 15b and 25b and the reflector bus bars 30a and 30b. For example, (the cross-sectional area of the reflective electrode fingers 30c × the number of the reflective electrode fingers 30c) <(the cross-sectional area of the reflector bus bar 30b). For this reason, in the acoustic wave resonator 510 in the comparative example, the electrical resistance for connecting the IDT electrodes 11 and 22 increases, and it is difficult to reduce the insertion loss of the acoustic wave resonator 510.
　図５は、実施の形態１および比較例におけるフィルタ装置の挿入損失を示す図である。 FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example.
　実施の形態１のフィルタ装置（送信フィルタ７）では、図１に示す直列腕共振子２ｂが、本実施の形態の弾性波共振器１０を含む構成となっている。それに対し、比較例のフィルタ装置では、図１に示す直列腕共振子２ｂが、比較例の弾性波共振器５１０を含む構成となっている。 In the filter device (transmission filter 7) of the first embodiment, the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 10 of the present embodiment. On the other hand, in the filter device of the comparative example, the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 of the comparative example.
　図５に示すように、例えば、周波数８３６ＭＨｚにおいて、比較例のフィルタ装置の通過帯域における挿入損失が０．９２ｄＢであるのに対し、実施の形態１のフィルタ装置の通過帯域における挿入損失は、０．９０ｄＢであり、比較例に比べて挿入損失が小さくなっている。 As shown in FIG. 5, for example, at a frequency of 836 MHz, the insertion loss in the passband of the filter device of the comparative example is 0.92 dB, whereas the insertion loss in the passband of the filter device of Embodiment 1 is 0. The insertion loss is smaller than that of the comparative example.
　図６は、実施の形態１および比較例におけるマルチプレクサの挿入損失を示す図である。 FIG. 6 is a diagram showing the insertion loss of the multiplexer in the first embodiment and the comparative example.
　図６に示すように、例えば、周波数８３６ＭＨｚにおいて、比較例のマルチプレクサの送信通過帯域における挿入損失が０．９４ｄＢであるのに対し、実施の形態１のマルチプレクサ１の送信通過帯域における挿入損失は、０．９２ｄＢであり、比較例に比べて挿入損失が小さくなっている。 As shown in FIG. 6, for example, at a frequency of 836 MHz, the insertion loss in the transmission passband of the multiplexer of the comparative example is 0.94 dB, whereas the insertion loss in the transmission passband of the multiplexer 1 of the first embodiment is The insertion loss is 0.92 dB, which is smaller than that of the comparative example.
　本実施の形態の弾性波共振器１０では、ＩＤＴ電極１１、２２が、櫛歯バスバー１５ｂ、反射器バスバー３０ｂおよび櫛歯バスバー２５ｂを用いて接続されているので、ＩＤＴ電極１１、２２を接続するための電気抵抗を小さくすることができる。これにより、弾性波共振器１０の挿入損失を小さくすることができる。 In the acoustic wave resonator 10 of the present embodiment, the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, and therefore the IDT electrodes 11 and 22 are connected. Therefore, the electrical resistance can be reduced. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
　（実施の形態２）
　次に、実施の形態２に係る弾性波共振器１０Ａについて説明する。なお、実施の形態２のマルチプレクサ、フィルタ装置については、実施の形態１と回路構成が同じであるので説明を省略する。 (Embodiment 2)
Next, an acoustic wave resonator 10A according to Embodiment 2 will be described. Note that the multiplexer and filter device of the second embodiment have the same circuit configuration as that of the first embodiment, and therefore the description thereof is omitted.
　図７は、実施の形態２に係る弾性波共振器１０Ａを表す平面図である。図８は、弾性波共振器１０Ａの等価回路である。 FIG. 7 is a plan view showing an acoustic wave resonator 10A according to the second embodiment. FIG. 8 is an equivalent circuit of the acoustic wave resonator 10A.
　この弾性波共振器１０Ａは、実施の形態１の弾性波共振器１０に、さらに、第３接続電極５３と、第４接続電極５４とを備えている。 This elastic wave resonator 10A is further provided with a third connection electrode 53 and a fourth connection electrode 54 in addition to the elastic wave resonator 10 of the first embodiment.
　具体的には、他方の反射器バスバー３１ｂと他方の櫛歯バスバー１５ｂとの間に、第３接続電極５３が設けられ、他方の櫛歯バスバー２５ｂと他方の反射器バスバー３２ｂとの間に、第４接続電極５４が設けられている。第３接続電極５３は、反射器バスバー３１ｂと櫛歯バスバー１５ｂとを接続し、第４接続電極５４は、櫛歯バスバー２５ｂと反射器バスバー３２ｂとを接続している。反射器バスバー３１ｂ、接続電極５３、櫛歯バスバー１５ｂ、接続電極５１、反射器バスバー３０ｂ、接続電極５２、櫛歯バスバー２５ｂ、接続電極５４および反射器バスバー３２ｂのそれぞれは、幅、厚みが等しく、所定方向Ｄ１に沿って直線状に一体となって形成されている。 Specifically, a third connection electrode 53 is provided between the other reflector bus bar 31b and the other comb bus bar 15b, and between the other comb bus bar 25b and the other reflector bus bar 32b, A fourth connection electrode 54 is provided. The third connection electrode 53 connects the reflector bus bar 31b and the comb bus bar 15b, and the fourth connection electrode 54 connects the comb bus bar 25b and the reflector bus bar 32b. The reflector bus bar 31b, the connection electrode 53, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, the comb-tooth bus bar 25b, the connection electrode 54, and the reflector bus bar 32b have the same width and thickness, It is integrally formed linearly along the predetermined direction D1.
　弾性波共振器１０Ａは、ＩＤＴ電極１１、２２で構成されるそれぞれの弾性波素子Ｆ１、Ｆ２に対応して、容量Ｃ３、Ｃ４を有している（図８参照）。具体的には、容量Ｃ３は、接続されたバスバーの反対側に位置する、一方の櫛歯バスバー１５ａと一方の反射器バスバー３０ａとが、異なる電位をもって対向すること、および、一方の反射器バスバー３１ａと一方の櫛歯バスバー１５ａが異なる電位をもって対向することで形成されている。容量Ｃ４は、接続されたバスバーの反対側に位置する、一方の反射器バスバー３０ａと一方の櫛歯バスバー２５ａとが異なる電位を持って対向すること、および、一方の櫛歯バスバー２５ａと一方の反射器バスバー３２ａとが異なる電位をもって対向することで形成される。このように、弾性波共振器１０が容量Ｃ３、Ｃ４を有することで、弾性波共振器１０Ａの通過帯域における急峻性を向上することができる。 The acoustic wave resonator 10A has capacitors C3 and C4 corresponding to the respective acoustic wave elements F1 and F2 constituted by the IDT electrodes 11 and 22 (see FIG. 8). Specifically, the capacitor C3 has one comb-shaped bus bar 15a and one reflector bus bar 30a facing each other at different potentials, and one reflector bus bar located on the opposite side of the connected bus bar. 31a and one comb-shaped bus bar 15a are formed by facing each other with different potentials. The capacitor C4 is located on the opposite side of the connected bus bar so that one reflector bus bar 30a and the one comb bus bar 25a face each other with different potentials, and one comb bus bar 25a and one comb bus bar 25a It is formed by facing the reflector bus bar 32a with a different potential. As described above, since the acoustic wave resonator 10 includes the capacitors C3 and C4, the steepness in the passband of the acoustic wave resonator 10A can be improved.
　図９は、実施の形態２および比較例における弾性波共振器の挿入損失を示す図である。 FIG. 9 is a diagram showing the insertion loss of the acoustic wave resonator in the second embodiment and the comparative example.
　図９に示すように、例えば、周波数８４６ＭＨｚから８５７ＭＨｚへの変化に対して、比較例の弾性波共振器５１０の挿入損失の増大値が５．６２ｄＢであるのに対し、実施の形態２の弾性波共振器１０Ａの挿入損失の増大値は、５．９２ｄＢであり、比較例に比べて急峻性が高くなっている。 As shown in FIG. 9, for example, with respect to a change from a frequency of 846 MHz to 857 MHz, the increase value of the insertion loss of the elastic wave resonator 510 of the comparative example is 5.62 dB, whereas the elasticity of the second embodiment is The increase value of the insertion loss of the wave resonator 10A is 5.92 dB, which is higher than the comparative example.
　図１０は、実施の形態２および比較例におけるフィルタ装置の挿入損失を示す図である。 FIG. 10 is a diagram showing the insertion loss of the filter device in the second embodiment and the comparative example.
　実施の形態２のフィルタ装置（送信フィルタ７）では、図１に示す直列腕共振子２ｂが、本実施の形態の弾性波共振器１０Ａを含む構成となっている。それに対し、比較例のフィルタ装置では、図１に示す直列腕共振子２ｂが、比較例の弾性波共振器５１０（図４参照）を含む構成となっている。 In the filter device (transmission filter 7) of the second embodiment, the series arm resonator 2b shown in FIG. 1 includes the acoustic wave resonator 10A of the present embodiment. On the other hand, in the filter device of the comparative example, the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 (see FIG. 4) of the comparative example.
　図１０に示すように、例えば、周波数８５６ＭＨｚから８６５ＭＨｚへの変化に対して、比較例のフィルタ装置の通過帯域における挿入損失の増大値が２７・０５ｄＢであるのに対し、実施の形態２のフィルタ装置の通過帯域における挿入損失の増大値は、２９．２４ｄＢであり、比較例に比べて急峻性が高くなっている。 As shown in FIG. 10, for example, with respect to a change from a frequency of 856 MHz to 865 MHz, the increase value of the insertion loss in the passband of the filter device of the comparative example is 27 · 05 dB, whereas the filter of the second embodiment The increase value of the insertion loss in the pass band of the device is 29.24 dB, which is higher than the comparative example.
　図１１は、実施の形態２および比較例におけるマルチプレクサの周波数特性を示す図であって、（ａ）は挿入損失、（ｂ）はアイソレーション特性を示す図である。なお、アイソレーション特性は、図１に示すマルチプレクサにおいて、Ｔｘ－Ｒｘ間の挿入損失を測定することで求めた。 FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss, and (b) is a diagram illustrating an isolation characteristic. The isolation characteristic was obtained by measuring the insertion loss between Tx and Rx in the multiplexer shown in FIG.
　図１１の（ａ）に示すように、例えば、周波数８５６ＭＨｚから８６５ＭＨｚへの変化に対して、比較例のマルチプレクサの送信通過帯域における挿入損失の増大値が２７．１８ｄＢであるのに対し、実施の形態２のマルチプレクサ１の送信通過帯域における挿入損失の増大値は、２９．１３ｄＢであり、比較例に比べて急峻性が高くなっている。 As shown in FIG. 11A, for example, with respect to the change from the frequency 856 MHz to 865 MHz, the increase value of the insertion loss in the transmission passband of the multiplexer of the comparative example is 27.18 dB. The increase value of the insertion loss in the transmission pass band of the multiplexer 1 of the form 2 is 29.13 dB, which is higher than the comparative example.
　また、図１１の（ｂ）に示すように、実施の形態２は、比較例に対して、Ｔｘロスが２ｄＢである周波数ｆΔ１とＲｘ帯Ｉｓｏが５０ｄＢである周波数ｆΔ２との周波数差Δｆが０．３ＭＨｚ改善し（小さくなり）、アイソレーション性が向上している。 Also, as shown in FIG. 11B, the second embodiment has a frequency difference Δf between the frequency fΔ1 having a Tx loss of 2 dB and the frequency fΔ2 having an Rx band Iso of 50 dB as compared with the comparative example. .Improved (smaller) by 3 MHz and improved isolation.
　本実施の形態に係る弾性波共振器１０Ａでは、実施の形態１に示す弾性波共振器１０の構成に加え、第１反射器３１の他方の反射器バスバー３１ｂと、ＩＤＴ電極１１の他方の櫛歯バスバー１５ｂとが所定方向Ｄ１に沿って配置され、互いに接続されている。また、ＩＤＴ電極２２の他方の櫛歯バスバー２５ｂと、第２反射器３２の他方の反射器バスバー３２ｂとが所定方向Ｄ１に沿って配置され、互いに接続されている。この構成によれば、弾性波共振器１０Ａがさらに容量を有することになるので、弾性波共振器１０Ａの通過帯域における急峻性を向上することができる。なお、弾性波共振器１０Ａでは、反射器バスバー３１ｂと櫛歯バスバー１５ｂとが接続された状態、および、櫛歯バスバー２５ｂと反射器バスバー３２ｂとが接続された状態のうち、少なくとも一方の状態を有していれば上記効果を有する。 In the acoustic wave resonator 10A according to the present embodiment, in addition to the configuration of the acoustic wave resonator 10 shown in the first embodiment, the other reflector bus bar 31b of the first reflector 31 and the other comb of the IDT electrode 11 are combined. The tooth bus bar 15b is disposed along the predetermined direction D1 and connected to each other. Further, the other comb-tooth bus bar 25b of the IDT electrode 22 and the other reflector bus bar 32b of the second reflector 32 are arranged along the predetermined direction D1 and connected to each other. According to this configuration, since the acoustic wave resonator 10A further has a capacity, steepness in the pass band of the acoustic wave resonator 10A can be improved. In the acoustic wave resonator 10A, at least one of a state where the reflector bus bar 31b and the comb bus bar 15b are connected and a state where the comb bus bar 25b and the reflector bus bar 32b are connected is used. If it has, it has the said effect.
　（実施の形態３）
　図１２は、実施の形態３に係る弾性波共振器１０Ｂを表す平面図である。図１３は、弾性波共振器１０Ｂの等価回路である。 (Embodiment 3)
FIG. 12 is a plan view showing an acoustic wave resonator 10B according to the third embodiment. FIG. 13 is an equivalent circuit of the acoustic wave resonator 10B.
　この弾性波共振器１０Ｂは、実施の形態１の弾性波共振器１０に、さらに、第１対向電極６１を備えている。 This elastic wave resonator 10B is further provided with a first counter electrode 61 in addition to the elastic wave resonator 10 of the first embodiment.
　具体的には、直交方向Ｄ２において、共用反射器３０の一方の反射器バスバー３０ａから見て他方の反射器バスバー３０ｂと反対側に、一方の反射器バスバー３０ａと対向する第１対向電極６１が設けられている第１対向電極６１は、反射器バスバー３０ａに対して所定距離をあけて平行に設けられている。第１対向電極６１は、グランドに接続されている。なお、反射器バスバー３０ａと第１対向電極６１との間には、前述した保護層９３（例えば二酸化ケイ素）と同じ材料が充填されている。 Specifically, in the orthogonal direction D2, the first counter electrode 61 facing the one reflector bus bar 30a is provided on the side opposite to the other reflector bus bar 30b when viewed from the one reflector bus bar 30a of the shared reflector 30. The provided first counter electrode 61 is provided in parallel with a predetermined distance from the reflector bus bar 30a. The first counter electrode 61 is connected to the ground. In addition, the same material as the protective layer 93 (for example, silicon dioxide) mentioned above is filled between the reflector bus bar 30a and the first counter electrode 61.
　この構造により、弾性波共振器１０Ｂは、図１３に示すように、容量Ｃ１、Ｃ２に加えて容量Ｃ５を有する。容量Ｃ５は、一方の反射器バスバー３０ａと第１対向電極６１とが、異なる電位をもって対向することで形成される。このように、弾性波共振器１０Ｂが、さらに容量Ｃ５を有することで、弾性波共振器１０Ｂの通過帯域における急峻性を向上することができる。 With this structure, the acoustic wave resonator 10B has a capacitor C5 in addition to the capacitors C1 and C2, as shown in FIG. The capacitor C5 is formed by facing one reflector bus bar 30a and the first counter electrode 61 with different potentials. As described above, since the acoustic wave resonator 10B further includes the capacitor C5, the steepness in the pass band of the acoustic wave resonator 10B can be improved.
　（実施の形態４）
　図１４は、実施の形態４に係る弾性波共振器１０Ｃを表す図であって、（ａ）は平面図、（ｂ）は（ａ）に示すＸＩＶＢ－ＸＩＶＢ線の断面図である。図１５は、弾性波共振器１０Ｃの等価回路である。なお、図１４の（ｂ）では、密着層９１、主電極層９２および保護層９３の図示を省略している。 (Embodiment 4)
14A and 14B are diagrams illustrating an acoustic wave resonator 10C according to the fourth embodiment, where FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG. 14A. FIG. 15 is an equivalent circuit of the acoustic wave resonator 10C. In FIG. 14B, illustration of the adhesion layer 91, the main electrode layer 92, and the protective layer 93 is omitted.
　この弾性波共振器１０Ｃは、実施の形態１の弾性波共振器１０に、さらに、第２対向電極６２を備えている。 This elastic wave resonator 10C is further provided with a second counter electrode 62 in addition to the elastic wave resonator 10 of the first embodiment.
　具体的には、共用反射器３０の一方の反射器バスバー３０ａ上、および、ＩＤＴ電極１１、２２のそれぞれの一方の櫛歯バスバー１５ａ、２５ａ上に、絶縁層６３が設けられている。絶縁層６３上には、一方の反射器バスバー３０ａおよび一方の櫛歯バスバー１５ａ、２５ａと厚み方向に対向する第２対向電極６２が設けられている。第２対向電極６２は、所定方向Ｄ１に沿って延び、所定方向Ｄ１のマイナス側の端部は一方の反射器バスバー３１ａに接続され、プラス側の端部は、一方の反射器バスバー３２ａに接続されている。また、第２対向電極６２は、グランドに接続されている。絶縁層６３の材質は、例えば、二酸化ケイ素、ポリイミドから適宜選択される。 Specifically, an insulating layer 63 is provided on one reflector bus bar 30a of the shared reflector 30 and one comb- tooth bus bars 15a and 25a of the IDT electrodes 11 and 22, respectively. On the insulating layer 63, a second counter electrode 62 is provided to face one reflector bus bar 30a and one comb- tooth bus bar 15a, 25a in the thickness direction. The second counter electrode 62 extends along the predetermined direction D1, the negative end of the predetermined direction D1 is connected to one reflector bus bar 31a, and the positive end is connected to one reflector bus bar 32a. Has been. The second counter electrode 62 is connected to the ground. The material of the insulating layer 63 is appropriately selected from, for example, silicon dioxide and polyimide.
　この構造により、弾性波共振器１０Ｃは、図１５に示すように、容量Ｃ３、Ｃ４に加えて容量Ｃ６を有する。容量Ｃ６は、反射器バスバー３０ａ、櫛歯バスバー１５ａ、２５ａと、第２対向電極６２とが、絶縁層６３を挟んで対向し、異なる電位をもつことで形成される。このように、弾性波共振器１０Ｃが、さらに容量Ｃ６を有することで、弾性波共振器１０Ｃの通過帯域における急峻性を向上することができる。 With this structure, the acoustic wave resonator 10C has a capacitor C6 in addition to the capacitors C3 and C4 as shown in FIG. The capacitor C6 is formed by the reflector bus bar 30a, the comb- tooth bus bars 15a and 25a, and the second counter electrode 62 facing each other across the insulating layer 63 and having different potentials. As described above, since the acoustic wave resonator 10C further includes the capacitor C6, the steepness in the pass band of the acoustic wave resonator 10C can be improved.
　（その他の形態など）
　以上、本発明の実施の形態に係る弾性波共振器、フィルタ装置およびマルチプレクサについて説明したが、本発明は、上記実施の形態には限定されない。例えば、上記実施の形態に次のような変形を施した態様も、本発明に含まれる。 (Other forms etc.)
The acoustic wave resonator, the filter device, and the multiplexer according to the embodiment of the present invention have been described above, but the present invention is not limited to the above embodiment. For example, an aspect in which the following embodiment is modified as described below is also included in the present invention.
　例えば、弾性波共振器１０～１０Ｃは、弾性表面波共振器に限られず、弾性境界波共振器であってもよい。 For example, the acoustic wave resonators 10 to 10C are not limited to surface acoustic wave resonators, and may be boundary acoustic wave resonators.
　例えば、弾性波共振器１０～１０Ｃでは、櫛歯状電極１１ａ、１１ｂ、２２ａ、２２ｂにオフセット電極指１７、２７を設けることで、高調波などに起因する不要な周波数成分であるスプリアスなどを抑制している。ただし、それに限られず、櫛歯状電極１１ａ、１１ｂ、２２ａ、２２ｂの電極指は、オフセット電極指１７、２７を有せず、交差電極指１６、２６のみで構成されていてもよい。 For example, in the acoustic wave resonators 10 to 10C, by providing the offset electrode fingers 17 and 27 on the comb- like electrodes 11a, 11b, 22a, and 22b, spurious that is an unnecessary frequency component caused by harmonics and the like is suppressed. is doing. However, the electrode fingers of the comb-shaped electrodes 11a, 11b, 22a, and 22b are not limited thereto, and may include the cross electrode fingers 16 and 26 without the offset electrode fingers 17 and 27.
　また、弾性波共振器１０の密着層９１、主電極層９２および保護層９３を構成する材料は、上述した材料に限定されない。さらに、ＩＤＴ電極１１、２２は、上記積層構造でなくてもよい。ＩＤＴ電極１１、２２は、例えば、Ｔｉ、Ａｌ、Ｃｕ、Ｐｔ、Ａｕ、Ａｇ、Ｐｄなどの金属または合金から構成されてもよく、また、上記の金属または合金から構成される複数の積層体から構成されてもよい。また、保護層９３は、形成されていなくてもよい。 Further, the materials constituting the adhesion layer 91, the main electrode layer 92, and the protective layer 93 of the acoustic wave resonator 10 are not limited to the materials described above. Furthermore, the IDT electrodes 11 and 22 do not have to have the above laminated structure. The IDT electrodes 11 and 22 may be made of, for example, a metal or an alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd. It may be configured. Further, the protective layer 93 may not be formed.
　また、弾性波共振器１０の圧電基板９０は、高音速支持基板と、低音速膜と、圧電膜とがこの順で積層された積層構造であってもよい。圧電膜は、例えば、５０°ＹカットＸ伝搬ＬｉＴａＯ３圧電単結晶または圧電セラミックス（Ｘ軸を中心軸としてＹ軸から５０°回転した軸を法線とする面で切断したタンタル酸リチウム単結晶、またはセラミックスであって、Ｘ軸方向に弾性表面波が伝搬する単結晶またはセラミックス）からなる。圧電膜は、例えば、厚みが６００ｎｍである。高音速支持基板は、低音速膜、圧電膜ならびにＩＤＴ電極を支持する基板である。高音速支持基板は、さらに、圧電膜を伝搬する表面波や境界波の弾性波よりも、高音速支持基板中のバルク波の音速が高速となる基板であり、弾性表面波を圧電膜および低音速膜が積層されている部分に閉じ込め、高音速支持基板より下方に漏れないように機能する。高音速支持基板は、例えば、シリコン基板であり、厚みは、例えば２００μｍである。低音速膜は、圧電膜を伝搬するバルク波よりも、低音速膜中のバルク波の音速が低速となる膜であり、圧電膜と高音速支持基板との間に配置される。この構造と、弾性波が本質的に低音速な媒質にエネルギーが集中するという性質とにより、弾性表面波エネルギーのＩＤＴ電極外への漏れが抑制される。低音速膜は、例えば、二酸化ケイ素を主成分とする膜であり、厚みは、例えば６７０ｎｍである。この積層構造によれば、圧電基板９０を単層で使用している構造と比較して、共振周波数および反共振周波数におけるＱ値を大幅に高めることが可能となる。すなわち、Ｑ値が高い弾性表面波共振器を構成し得るので、当該弾性表面波共振器を用いて、挿入損失が小さいフィルタを構成することが可能となる。 Further, the piezoelectric substrate 90 of the acoustic wave resonator 10 may have a laminated structure in which a high sound velocity supporting substrate, a low sound velocity film, and a piezoelectric film are laminated in this order. The piezoelectric film may be, for example, a 50 ° Y-cut X-propagating LiTaO 3 piezoelectric single crystal or a piezoelectric ceramic (a lithium tantalate single crystal cut along a plane whose axis is rotated by 50 ° from the Y axis with the X axis as the central axis, Alternatively, it is made of ceramic and is made of a single crystal or ceramic in which surface acoustic waves propagate in the X-axis direction. The piezoelectric film has a thickness of 600 nm, for example. The high sound velocity support substrate is a substrate that supports the low sound velocity film, the piezoelectric film, and the IDT electrode. The high-sonic support substrate is a substrate in which the acoustic velocity of the bulk wave in the high-sonic support substrate is higher than that of the surface wave or boundary wave that propagates through the piezoelectric film. It functions in such a way that it is confined in the portion where the sonic film is laminated and does not leak below the high sonic support substrate. The high sound speed support substrate is, for example, a silicon substrate and has a thickness of, for example, 200 μm. The low acoustic velocity film is a membrane in which the acoustic velocity of the bulk wave in the low acoustic velocity film is lower than the bulk wave propagating through the piezoelectric membrane, and is disposed between the piezoelectric membrane and the high acoustic velocity support substrate. Due to this structure and the property that energy is concentrated in a medium where acoustic waves are essentially low in sound velocity, leakage of surface acoustic wave energy to the outside of the IDT electrode is suppressed. The low acoustic velocity film is, for example, a film mainly composed of silicon dioxide and has a thickness of, for example, 670 nm. According to this laminated structure, the Q value at the resonance frequency and the anti-resonance frequency can be significantly increased as compared with a structure in which the piezoelectric substrate 90 is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be configured, a filter with a small insertion loss can be configured using the surface acoustic wave resonator.
　また、本実施の形態では、所定方向Ｄ１が弾性波伝搬方向と同じ方向である例を示したが、それに限られず、所定方向Ｄ１は、弾性波伝搬方向に対して多少傾いた方向であってもよい。例えば、実施の形態１における櫛歯バスバー１５ａ、１５ｂ、２５ａ、２５ｂおよび反射器バスバー３０ａ、３０ｂ、３１ａ、３１ｂ、３２ａ、３２ｂのそれぞれが、弾性波伝搬方向に対して、０°以上１０°以下傾いた方向に延びて形成されていてもよい。その場合、交差電極指１６、２６、オフセット電極指１７、２７および反射電極指３０ｃ、３１ｃ、３２ｃのそれぞれは、弾性波伝搬方向に対して直交する方向に延びて形成されていればよい。また、その場合、弾性波共振器１０の波長は、弾性波伝搬方向における交差電極指１６、２６のそれぞれの繰り返しピッチλで規定すればよい。 In the present embodiment, an example in which the predetermined direction D1 is the same direction as the elastic wave propagation direction has been described. However, the present invention is not limited thereto, and the predetermined direction D1 is a direction slightly inclined with respect to the elastic wave propagation direction. Also good. For example, each of the comb- tooth bus bars 15a, 15b, 25a, 25b and the reflector bus bars 30a, 30b, 31a, 31b, 32a, 32b in the first embodiment is 0 ° or more and 10 ° or less with respect to the elastic wave propagation direction. It may be formed extending in an inclined direction. In that case, each of the crossed electrode fingers 16, 26, the offset electrode fingers 17, 27, and the reflective electrode fingers 30c, 31c, 32c may be formed so as to extend in a direction orthogonal to the elastic wave propagation direction. In this case, the wavelength of the acoustic wave resonator 10 may be defined by the repetition pitch λ of each of the cross electrode fingers 16 and 26 in the acoustic wave propagation direction.
　本発明は、挿入損失が小さい弾性波共振器、フィルタ装置、デュプレクサおよびマルチプレクサとして、携帯電話などの移動体通信機に広く利用できる。 The present invention can be widely used in mobile communication devices such as mobile phones as acoustic wave resonators, filter devices, duplexers, and multiplexers with low insertion loss.
　１　　　マルチプレクサ
　２ａ、２ｂ、２ｃ、２ｄ　直列腕共振子
　３ａ、３ｂ、３ｃ　並列腕共振子
　４　　　　直列共振子
　５　　　　縦結合型弾性波フィルタ部
　６ａ、６ｂ、６ｃ　入出力端子
　７　　　　送信フィルタ（フィルタ装置）
　８　　　　受信フィルタ（フィルタ装置）
　１０、１０Ａ、１０Ｂ、１０Ｃ　弾性波共振器
　１１　　第１ＩＤＴ電極
　１１ａ　一方の櫛歯状電極
　１１ｂ　他方の櫛歯状電極
　１５ａ　一方の櫛歯バスバー
　１５ｂ　他方の櫛歯バスバー
　１６　　交差電極指
　１７　　オフセット電極指
　２２　　第２ＩＤＴ電極
　２２ａ　一方の櫛歯状電極
　２２ｂ　他方の櫛歯状電極
　２５ａ　一方の櫛歯バスバー
　２５ｂ　他方の櫛歯バスバー
　２６　　交差電極指
　２７　　オフセット電極指
　３０　　共用反射器
　３０ａ　一方の反射器バスバー
　３０ｂ　他方の反射器バスバー
　３０ｃ　反射電極指
　３１　　第１反射器
　３１ａ　一方の反射器バスバー
　３１ｂ　他方の反射器バスバー
　３１ｃ　反射電極指
　３２　　第２反射器
　３２ａ　一方の反射器バスバー
　３２ｂ　他方の反射器バスバー
　３２ｃ　反射電極指
　４１　　第１入出力配線
　４２　　第２入出力配線
　５１　　第１接続電極
　５２　　第２接続電極
　５３　　第３接続電極
　５４　　第４接続電極
　６１　　第１対向電極
　６２　　第２対向電極
　６３　　絶縁層
　９０　　圧電基板
　９１　　密着層
　９２　　主電極層
　９３　　保護層
　Ｄ１　　所定方向
　Ｄ２　　直交方向
　Ｆ１、Ｆ２　弾性波素子 DESCRIPTION OF SYMBOLS 1 Multiplexer 2a, 2b, 2c, 2d Series arm resonator 3a, 3b, 3c Parallel arm resonator 4 Series resonator 5 Longitudinal coupling type | mold elastic wave filter part 6a, 6b, 6c Input / output terminal 7 Transmission filter (filter apparatus)
8 Reception filter (filter device)
10, 10A, 10B, 10C Elastic wave resonator 11 First IDT electrode 11a One comb-like electrode 11b The other comb-like electrode 15a One comb-like bus bar 15b The other comb-like bus bar 16 Cross electrode finger 17 Offset electrode finger 22 Second IDT electrode 22a One comb-shaped electrode 22b The other comb-shaped electrode 25a One comb-shaped bus bar 25b The other comb-shaped bus bar 26 Crossed electrode finger 27 Offset electrode finger 30 Shared reflector 30a One reflector bus bar 30b The other Reflector bus bar 30c Reflective electrode finger 31 First reflector 31a One reflector bus bar 31b Other reflector bus bar 31c Reflective electrode finger 32 Second reflector 32a One reflector bus bar 32b Other reflector bus bar 32c Reflective electrode finger 41 First input / output wiring 42 Second input / output wiring 51 First Connection electrode 52 Second connection electrode 53 Third connection electrode 54 Fourth connection electrode 61 First counter electrode 62 Second counter electrode 63 Insulating layer 90 Piezoelectric substrate 91 Adhering layer 92 Main electrode layer 93 Protective layer D1 Predetermined direction D2 Orthogonal direction F1 , F2 elastic wave element

Claims (9)

  1. 　圧電基板と、
    　互いに対向する一対の櫛歯状電極を有するＩＤＴ電極であって、前記圧電基板上に設けられ、所定方向に沿って配置された第１ＩＤＴ電極および第２ＩＤＴ電極と、
    　前記圧電基板上に設けられ、前記所定方向において前記第１ＩＤＴ電極と前記第２ＩＤＴ電極との間に配置された共用反射器と
    　を備え、
    　前記共用反射器は、前記所定方向に延びて前記所定方向の直交方向に互いに対向する一方の反射器バスバーおよび他方の反射器バスバーを有し、
    　前記第１ＩＤＴ電極および前記第２ＩＤＴ電極のそれぞれは、前記所定方向に延びて前記直交方向に互いに対向する一方の櫛歯バスバーおよび他方の櫛歯バスバーを有し、
    　前記第１ＩＤＴ電極の前記他方の櫛歯バスバーと、前記共用反射器の前記他方の反射器バスバーと、前記第２ＩＤＴ電極の前記他方の櫛歯バスバーとが、前記所定方向に沿って配置され、接続されている
    　弾性波共振器。     A piezoelectric substrate;
    An IDT electrode having a pair of comb-like electrodes facing each other, the first IDT electrode and the second IDT electrode provided on the piezoelectric substrate and arranged along a predetermined direction;
    A shared reflector provided on the piezoelectric substrate and disposed between the first IDT electrode and the second IDT electrode in the predetermined direction;
    The shared reflector has one reflector bus bar and the other reflector bus bar extending in the predetermined direction and facing each other in a direction orthogonal to the predetermined direction,
    Each of the first IDT electrode and the second IDT electrode has one comb-shaped bus bar and the other comb-shaped bus bar that extend in the predetermined direction and face each other in the orthogonal direction,
    The other comb-tooth busbar of the first IDT electrode, the other reflector busbar of the shared reflector, and the other comb-tooth busbar of the second IDT electrode are arranged along the predetermined direction and connected An elastic wave resonator.
  2. 　前記第１ＩＤＴ電極の前記他方の櫛歯バスバーと前記共用反射器の前記他方の反射器バスバーとは、当該他方の櫛歯バスバーと前記他方の反射器バスバーとの間に位置する第１接続電極を介して接続され、
    　前記他方の反射器バスバーと前記第２ＩＤＴ電極の前記他方の櫛歯バスバーとは、前記他方の反射器バスバーと当該他方の櫛歯バスバーとの間に位置する第２接続電極を介して接続されている
    　請求項１に記載の弾性波共振器。     The other comb-tooth bus bar of the first IDT electrode and the other reflector bus bar of the shared reflector are provided with a first connection electrode positioned between the other comb-tooth bus bar and the other reflector bus bar. Connected through
    The other reflector bus bar and the other comb-tooth bus bar of the second IDT electrode are connected via a second connection electrode located between the other reflector bus bar and the other comb-tooth bus bar. The elastic wave resonator according to claim 1.
  3. 　前記第１ＩＤＴ電極の前記一方の櫛歯バスバーに第１入出力配線が接続され、
    　前記第２ＩＤＴ電極の前記一方の櫛歯バスバーに第２入出力配線が接続され、
    　前記第１入出力配線と前記第２入出力配線とを結ぶ経路において、前記第１ＩＤＴ電極と前記第２ＩＤＴ電極とは直列接続されている
    　請求項２に記載の弾性波共振器。     A first input / output wiring is connected to the one comb-teeth bus bar of the first IDT electrode;
    A second input / output wiring is connected to the one comb-shaped bus bar of the second IDT electrode;
    The elastic wave resonator according to claim 2, wherein the first IDT electrode and the second IDT electrode are connected in series in a path connecting the first input / output wiring and the second input / output wiring.
  4. 　さらに、
    　前記圧電基板上に設けられ、前記所定方向において前記第１ＩＤＴ電極から見て前記共用反射器と反対側に設けられた第１反射器と、
    　前記圧電基板上に設けられ、前記所定方向において前記第２ＩＤＴ電極から見て前記共用反射器と反対側に設けられた第２反射器とを備え、
    　前記第１反射器および前記第２反射器のそれぞれは、前記所定方向に延びて前記直交方向に互いに対向する一方の反射器バスバーおよび他方の反射器バスバーを有し、
    　前記第１反射器の前記他方の反射器バスバーと、前記第１ＩＤＴ電極の前記他方の櫛歯バスバーとが前記所定方向に沿って配置され、互いに接続されている、および／または、前記第２ＩＤＴ電極の前記他方の櫛歯バスバーと、前記第２反射器の前記他方の反射器バスバーとが前記所定方向に沿って配置され、互いに接続されている
    　請求項１～３のいずれか１項に記載の弾性波共振器。     further,
    A first reflector provided on the piezoelectric substrate and provided on a side opposite to the shared reflector as viewed from the first IDT electrode in the predetermined direction;
    A second reflector provided on the piezoelectric substrate and provided on the opposite side of the shared reflector as viewed from the second IDT electrode in the predetermined direction;
    Each of the first reflector and the second reflector has one reflector bus bar and the other reflector bus bar extending in the predetermined direction and facing each other in the orthogonal direction,
    The other reflector bus bar of the first reflector and the other comb-tooth bus bar of the first IDT electrode are arranged along the predetermined direction and connected to each other, and / or the second IDT electrode. The other comb-tooth busbar of the second reflector and the other reflector busbar of the second reflector are arranged along the predetermined direction and connected to each other. Elastic wave resonator.
  5. 　さらに、
    　前記直交方向において、前記共用反射器の前記一方の反射器バスバーから見て前記共用反射器の前記他方の反射器バスバーと反対側に、当該一方の反射器バスバーと対向する第１対向電極が設けられ、
    　前記第１対向電極は、グランドに接続されている
    　請求項１～４のいずれか１項に記載の弾性波共振器。     further,
    In the orthogonal direction, a first counter electrode facing the one reflector bus bar is provided on the side opposite to the other reflector bus bar of the shared reflector as viewed from the one reflector bus bar of the shared reflector. And
    The elastic wave resonator according to any one of claims 1 to 4, wherein the first counter electrode is connected to a ground.
  6. 　さらに、
    　前記共用反射器の前記一方の反射器バスバー上、および、前記第１ＩＤＴ電極および前記第２ＩＤＴ電極のそれぞれの前記一方の櫛歯バスバー上に、絶縁層が設けられ、
    　前記絶縁層上に、当該一方の反射器バスバーおよび当該一方の櫛歯バスバーと対向する第２対向電極が設けられ、
    　前記第２対向電極は、グランドに接続されている
    　請求項１～５のいずれか１項に記載の弾性波共振器。     further,
    An insulating layer is provided on the one reflector bus bar of the shared reflector and on the one comb-shaped bus bar of each of the first IDT electrode and the second IDT electrode,
    On the insulating layer, a second counter electrode facing the one reflector bus bar and the one comb-tooth bus bar is provided,
    The acoustic wave resonator according to any one of claims 1 to 5, wherein the second counter electrode is connected to a ground.
  7. 　１または複数の直列腕共振子、および、１または複数の並列腕共振子によって構成されるラダー型のフィルタ装置であって、
    　前記直列腕共振子および前記並列腕共振子の少なくとも１つは、請求項１～６のいずれか１項に記載の弾性波共振器を含む
    　フィルタ装置。     A ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators,
    The filter device including at least one of the series arm resonator and the parallel arm resonator including the acoustic wave resonator according to any one of claims 1 to 6.
  8. 　１または複数の直列腕共振子、および、１または複数の並列腕共振子によって構成されるラダー型のフィルタ装置であって、
    　前記直列腕共振子は、請求項１～６のいずれか１項に記載の弾性波共振器を含む
    　フィルタ装置。     A ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators,
    The filter device including the acoustic wave resonator according to any one of claims 1 to 6, wherein the series arm resonator is provided.
  9. 　請求項７または８に記載のフィルタ装置を含む
    　マルチプレクサ。     A multiplexer including the filter device according to claim 7.
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