Composite electronic component

A composite electronic component includes a first acoustic wave filter, a second acoustic wave filter, a spacer layer, and a switch. The second acoustic wave filter faces the first acoustic wave filter in a first direction. The switch switches an ON state and an OFF state of the first acoustic wave filter and an ON state and an OFF state of the second acoustic wave filter. A first functional electrode and a second functional electrode are located in a hollow space and face each other in the first direction. The switch brings at least one of the first acoustic wave filter and the second acoustic wave filter into the OFF state.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2017-248386 filed on Dec. 25, 2017. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a composite electronic component, and more particularly, to a composite electronic component including a plurality of acoustic wave filters.

2. Description of the Related Art

There has been known a structure including two acoustic wave devices (see, for example, International Publication No. 2017/110308).

In the structure described in International Publication No. 2017/110308, one acoustic wave device is arranged above the other acoustic wave device. The one acoustic wave device is inverted with respect to the other acoustic wave device. In the structure described in International Publication No. 2017/110308, the principal surfaces of the two acoustic wave devices in which interdigital transducer (IDT) electrodes are provided face each other with a hollow space interposed therebetween.

In the composite electronic component having the structure described in International Publication No. 2017/110308, when the two acoustic wave devices are used as acoustic wave filters and when the two acoustic wave filters are turned ON simultaneously, a problem arises in that the acoustic wave filters may interfere with each other. That is, when the two acoustic wave filters are brought into a state in which signals are able to pass through both of the acoustic wave filters, noise propagates from one of the two acoustic wave filters to the other. The description “the acoustic wave filter is turned ON” refers to a state in which a signal is able to pass through the acoustic wave filter.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide composite electronic components in each of which interference between acoustic wave filters is able to be reduced or prevented.

According to a preferred embodiment of the present invention, a composite electronic component includes a first acoustic wave filter, a second acoustic wave filter, a spacer layer, and a switch. The second acoustic wave filter faces the first acoustic wave filter in a first direction. The spacer layer has a substantially frame shape and is provided between the first acoustic wave filter and the second acoustic wave filter in the first direction. The switch switches an ON state and an OFF state of the first acoustic wave filter and an ON state and an OFF state of the second acoustic wave filter. The first acoustic wave filter includes a first support member and a first functional electrode. The first support member has piezoelectricity at least in a portion thereof. The first functional electrode is provided at a first principal surface of the first support member. The second acoustic wave filter includes a second support member and a second functional electrode. The second support member has piezoelectricity at least in a portion thereof. The second functional electrode is provided at a second principal surface of the second support member. A hollow space is defined by the first support member, the second support member, and the spacer layer. The first functional electrode and the second functional electrode are located in the hollow space and face each other in the first direction. The switch brings at least one of the first acoustic wave filter and the second acoustic wave filter into the OFF state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Composite electronic components according to preferred embodiments are described below with reference to the drawings.

FIGS. 1A and 1B,FIGS. 3A and 3B, andFIGS. 6A and 6Billustrating preferred embodiments are schematic diagrams or views and the ratios of sizes and thicknesses of elements in the figures do not essentially reflect actual dimensional ratios.

First Preferred Embodiment

First, the overall structure of a composite electronic component according to a first preferred embodiment of the present invention is described with reference to the drawings.

As illustrated inFIGS. 1A and 1B, a composite electronic component10according to the first preferred embodiment includes a first acoustic wave filter1, a second acoustic wave filter2, a third acoustic wave filter3, a fourth acoustic wave filter4, a spacer layer5, a plurality of (three in the illustrated example) external connection electrodes6, a switch7, a plurality of (three in the illustrated example) wiring members8, and a resin member9.

Next, elements of the composite electronic component10according to the first preferred embodiment are described with reference to the drawings.

The first acoustic wave filter1includes a first piezoelectric substrate11(first support member) and a first interdigital transducer (IDT) electrode12(first functional electrode).

The first piezoelectric substrate11supports the first IDT electrode12. The first piezoelectric substrate11is a substrate made of a piezoelectric material. As the piezoelectric material for the first piezoelectric substrate11, a piezoelectric material, such as LiTaO3, LiNbO3, or quartz crystal, for example, is preferably used as appropriate.

The first IDT electrode12faces a first principal surface111of the first piezoelectric substrate11in a first direction D1that is a thickness direction of the first piezoelectric substrate11. In the example ofFIG. 1A, the first IDT electrode12is provided on the first principal surface111of the first piezoelectric substrate11. The description “an n-th (n is a natural number) IDT electrode faces the principal surface of an n-th piezoelectric substrate” encompasses a case in which the n-th IDT electrode faces the principal surface of the n-th piezoelectric substrate while being spaced away from the principal surface and a case in which the n-th IDT electrode is provided on the principal surface of the n-th piezoelectric substrate. The case in which the n-th IDT electrode faces the principal surface of the n-th piezoelectric substrate while being spaced away from the principal surface encompasses, for example, a case in which an oxide film is provided on the principal surface of the n-th piezoelectric substrate and the n-th IDT electrode is provided on the oxide film.

The first IDT electrode12includes a plurality of electrode fingers121and two busbars (not illustrated). The plurality of electrode fingers121are disposed side by side in a second direction D2orthogonal or substantially orthogonal to the first direction D1that is the thickness direction of the first piezoelectric substrate11. The two busbars have a substantially elongated shape with the second direction D2as its longitudinal direction and are electrically connected to the plurality of electrode fingers121.

The second acoustic wave filter2includes a second piezoelectric substrate21(second support member) and a second IDT electrode22(second functional electrode).

The second piezoelectric substrate21supports the second IDT electrode22. The second piezoelectric substrate21is a substrate made of a piezoelectric material. As the piezoelectric material for the second piezoelectric substrate21, a piezoelectric material, such as LiTaO3, LiNbO3, or quartz crystal, for example, is preferably used as appropriate.

The second IDT electrode22faces a second principal surface211of the second piezoelectric substrate21in the first direction D1that is a thickness direction of the second piezoelectric substrate21. In the example ofFIG. 1A, the second IDT electrode22is provided on the second principal surface211of the second piezoelectric substrate21.

The second IDT electrode22includes a plurality of electrode fingers221and two busbars (not illustrated). The plurality of electrode fingers221are disposed side by side in the second direction D2. The two busbars have a substantially elongated shape with the second direction D2as its longitudinal direction and are electrically connected to the plurality of electrode fingers221.

The third acoustic wave filter3includes a third piezoelectric substrate31(third support member) and a third IDT electrode32(third functional electrode).

The third piezoelectric substrate31supports the third IDT electrode32. The third piezoelectric substrate31is a substrate made of a piezoelectric material. As the piezoelectric material for the third piezoelectric substrate31, a piezoelectric material, such as LiTaO3, LiNbO3, or quartz crystal, for example, is preferably used as appropriate.

The third IDT electrode32faces a third principal surface311of the third piezoelectric substrate31in the first direction D1that is a thickness direction of the third piezoelectric substrate31. In the example ofFIG. 1A, the third IDT electrode32is provided on the third principal surface311of the third piezoelectric substrate31.

The third IDT electrode32includes a plurality of electrode fingers321and two busbars (not illustrated). The plurality of electrode fingers321are disposed side by side in the second direction D2. The two busbars have a substantially elongated shape with the second direction D2as its longitudinal direction and are electrically connected to the plurality of electrode fingers321.

The fourth acoustic wave filter4includes a fourth piezoelectric substrate41(fourth support member) and a fourth IDT electrode42(fourth functional electrode).

The fourth piezoelectric substrate41supports the fourth IDT electrode42. The fourth piezoelectric substrate41is a substrate made of a piezoelectric material. As the piezoelectric material for the fourth piezoelectric substrate41, a piezoelectric material, such as LiTaO3, LiNbO3, or quartz crystal, for example, is preferably used as appropriate.

The fourth IDT electrode42faces a fourth principal surface411of the fourth piezoelectric substrate41in the first direction D1that is a thickness direction of the fourth piezoelectric substrate41. In the example ofFIG. 1A, the fourth IDT electrode42is provided on the fourth principal surface411of the fourth piezoelectric substrate41.

The fourth IDT electrode42includes a plurality of electrode fingers421and two busbars (not illustrated). The plurality of electrode fingers421are disposed side by side in the second direction D2. The two busbars have a substantially elongated shape with the second direction D2as its longitudinal direction and are electrically connected to the plurality of electrode fingers421.

The spacer layer5is provided on the first principal surface111side of the first piezoelectric substrate11. More specifically, the spacer layer5is provided on a first wiring member81, a second wiring member82, and a side wall resin91. The spacer layer5has a substantially frame outer peripheral shape and surrounds the first IDT electrode12and the third IDT electrode32in plan view in the first direction D1that is the thickness direction of each of the first piezoelectric substrate11and the third piezoelectric substrate31. The spacer layer5also surrounds the second IDT electrode22and the fourth IDT electrode42in plan view in the first direction D1. The spacer layer5includes a through hole51that exposes the first IDT electrode12, the second IDT electrode22, the third IDT electrode32, and the fourth IDT electrode42.

The spacer layer5has electrical insulation properties. For example, the material for the spacer layer5is preferably a synthetic resin, such as an epoxy resin or a polyimide resin.

The plurality of external connection electrodes6include a first electrode61, a second electrode62, and a third electrode63. The first electrode61and the second electrode62are hot electrodes (signal terminals) and the third electrode63is a ground electrode (ground terminal). The plurality of external connection electrodes6correspond to the plurality of wiring members8on a one-to-one basis and are provided on the corresponding wiring members8so as to be exposed to the outside. For example, the plurality of external connection electrodes6are preferably made of an appropriate metal material such as Cu, Ni, Au, solder, or an alloy including any one of those metals as a main component.

The first electrode61and the second electrode62are a pair of signal terminals to input and output signals that pass through the first to fourth acoustic wave filters1to4.

The switch7is provided between each of the first piezoelectric substrate11and the third piezoelectric substrate31and each of the plurality of external connection electrodes6. The switch7is preferably a semiconductor switch made of a semiconductor material including silicon, for example, as a main component.

As illustrated inFIG. 2, the switch7includes a common terminal71and a plurality of (two in the illustrated example) selective terminals72and73. The common terminal71is electrically connected to a terminal105connected to an antenna300(seeFIG. 4). The first acoustic wave filter1and the third acoustic wave filter3are electrically connected to the selective terminal72. The second acoustic wave filter2and the fourth acoustic wave filter4are electrically connected to the selective terminal73. The switch7switches a selective terminal to be electrically connected to the common terminal71between the plurality of selective terminals72and73. That is, when the selective terminal72is electrically connected to the common terminal71, the switch7electrically disconnects the selective terminal73from the common terminal71. When the selective terminal73is electrically connected to the common terminal71, the switch7electrically disconnects the selective terminal72from the common terminal71.

As illustrated inFIG. 1A, the plurality of wiring members8include the first wiring member81, the second wiring member82, and a third wiring member83. The plurality of wiring members8electrically connect the first acoustic wave filter1, the second acoustic wave filter2, the third acoustic wave filter3, and the fourth acoustic wave filter4to the plurality of external connection electrodes6.

The material for each wiring member8is preferably an appropriate metal material such as Al, Cu, Pt, Au, Ag, Ti, Ni, Cr, Mo, W, or an alloy containing any one of those metals as a main component. Each wiring member8may have a structure in which a plurality of metal films formed of those metals or alloys are laminated.

The first wiring member81includes a signal line811connected to the first electrode61. The second wiring member82includes a signal line821connected to the second electrode62. The third wiring member83includes a reference potential line (ground line)831having a reference potential (ground).

If input/output terminals of the plurality of acoustic wave filters1to4are integrated, ISO, IMD, and other factors among the acoustic wave filters need to be taken into consideration. If an input/output terminal is provided for each acoustic wave filter, the number of terminals and the number of wires increase, thus increasing the area.

In view of this, the third wiring member83is provided between the first electrode61and the second electrode62and between the signal line811and the signal line821in the second direction D2. The distance between the signal line811and the signal line821is preferably, for example, about 90 μm or more and about 350 μm or less and the width of the reference potential line is preferably, for example, about 50 μm or more and about 150 μm or less.

Thus, in the pair of signal lines811and821, influence from one signal line to the other signal line is able to be reduced or prevented by the reference potential line831. That is, interference between the first electrode61and the second electrode62and interference between the signal line811and the signal line821is able to be reduced or prevented.

The resin member9includes the side wall resin91, a shell resin92, and a protective resin93. The side wall resin91surrounds the first piezoelectric substrate11and the third piezoelectric substrate31in plan view in the first direction D1. The shell resin92surrounds the second piezoelectric substrate21and the fourth piezoelectric substrate41in plan view in the first direction D1and is also provided on principal surfaces212and412opposite to the second principal surface211of the second piezoelectric substrate21and the fourth principal surface411of the fourth piezoelectric substrate41. The protective resin93covers the switch7and the plurality of wiring members8around the plurality of external connection electrodes6.

The resin member9has electrical insulation properties. For example, the material for the resin member9is preferably a synthetic resin, such as an epoxy resin or a polyimide resin, for example. The resin member9may be made of a single material or a plurality of materials. The resin member9may be made of an appropriate insulating material other than the resins described above.

First, the first piezoelectric substrate11and the third piezoelectric substrate31integrated with each other are prepared. Further, the second piezoelectric substrate21and the fourth piezoelectric substrate41integrated with each other are prepared.

Next, the first IDT electrode12and a first wiring layer13are formed on the first piezoelectric substrate11and the third IDT electrode32and a third wiring layer33are formed on the third piezoelectric substrate31. Similarly, the second IDT electrode22and a second wiring layer23are formed on the second piezoelectric substrate21and the fourth IDT electrode42and a fourth wiring layer43are formed on the fourth piezoelectric substrate41.

Then, the first wiring member81, the second wiring member82, and the third wiring member83are formed and the side wall resin91is formed.

Then, the first piezoelectric substrate11and the third piezoelectric substrate31are bonded to the second piezoelectric substrate21and the fourth piezoelectric substrate41using the spacer layer5so that the first IDT electrode12and the second IDT electrode22face each other and the third IDT electrode32and the fourth IDT electrode42face each other. A hollow space S1is formed by the first piezoelectric substrate11, the second piezoelectric substrate21, the third piezoelectric substrate31, the fourth piezoelectric substrate41, and the spacer layer5. Pressure bonding, ultrasonic bonding, interatomic bonding, or an adhesive may be used for the bonding.

Then, the shell resin92and the protective resin93are formed.

Next, an operation of the composite electronic component10according to the first preferred embodiment is described with reference toFIG. 2,FIGS. 3A and 3B.

The composite electronic component10has electrical connections as illustrated inFIG. 2. More specifically, a parallel circuit of the first acoustic wave filter1and the third acoustic wave filter3is electrically connected to the selective terminal72of the switch7. A parallel circuit of the second acoustic wave filter2and the fourth acoustic wave filter4is electrically connected to the selective terminal73of the switch7. A terminal101to which an external circuit (not illustrated) is connected is connected to the first acoustic wave filter1. Similarly, a terminal102to which an external circuit is connected is connected to the second acoustic wave filter2, a terminal103to which an external circuit is connected is connected to the third acoustic wave filter3, and a terminal104to which an external circuit is connected is connected to the fourth acoustic wave filter4. The terminal105to which the antenna300(seeFIG. 4) is connected is connected to the common terminal71of the switch7. The external circuits connected to the terminals101to104are circuits that are different from each other.

In the composite electronic component10according to the first preferred embodiment, the conduction state of the first to fourth acoustic wave filters1to4is switched between a first state illustrated inFIG. 3Aand a second state illustrated inFIG. 3Bunder control of the switch7.

In the first state, the common terminal71and the selective terminal72are electrically connected to each other and the common terminal71and the selective terminal73are electrically disconnected from each other. Thus, in the first state, the first acoustic wave filter1and the third acoustic wave filter3are in ON states and the second acoustic wave filter that faces the first acoustic wave filter1in the first direction D1and the fourth acoustic wave filter4that faces the third acoustic wave filter3in the first direction D1are in OFF states. That is, two acoustic wave filters adjacent to each other in the second direction D2are in the same state. The “ON state” refers to a state in which a signal is able to pass through the acoustic wave filter. The “OFF state” refers to a state in which a signal is not able to pass through the acoustic wave filter.

In the second state, the common terminal71and the selective terminal73are electrically connected to each other and the common terminal71and the selective terminal72are electrically disconnected from each other. Thus, in the second state, the first acoustic wave filter1and the third acoustic wave filter3are in OFF states and the second acoustic wave filter that faces the first acoustic wave filter1in the first direction D1and the fourth acoustic wave filter4that faces the third acoustic wave filter3in the first direction D1are in ON states. That is, two acoustic wave filters adjacent to each other in the second direction D2are in the same state.

In the composite electronic component10described above, the IDT electrodes that face each other are coupled to each other in terms of capacitances and magnetic fields. The intensity of the coupling depends on the areas of the IDT electrodes that face each other and the distance therebetween. Therefore, the switch7performs switching control so that only one of the two acoustic wave filters that face each other is brought into an ON state, thus being capable of reducing the influence of the coupling described above. As illustrated inFIGS. 3A and 3B, the composite electronic component10according to the first preferred embodiment brings only one of the first acoustic wave filter1and the second acoustic wave filter2and only one of the third acoustic wave filter3and the fourth acoustic wave filter4into the ON states. Thus, the capacitive and magnetic coupling between the first acoustic wave filter1and the second acoustic wave filter2is able to be reduced and the distance between the first acoustic wave filter1and the second acoustic wave filter2in the first direction D1is able to be reduced. Further, the capacitive and magnetic coupling between the third acoustic wave filter3and the fourth acoustic wave filter4is able to be reduced and the distance between the third acoustic wave filter3and the fourth acoustic wave filter4in the first direction D1is able to be reduced. As a result, the height of the composite electronic component10is able to be reduced.

The composite electronic component10described above is used in a communication device100.

As illustrated inFIG. 4, the communication device100includes a control unit200and the composite electronic component10. The first to fourth acoustic wave filters1to4have communication bands that differ from each other. That is, the communication device100is a multiband device.

For example, the control unit200is preferably an RFIC and gives an ON/OFF instruction to the switch7. More specifically, the switch7receives, from the control unit200, instructions related to the ON/OFF state of the first to fourth acoustic wave filters1to4. That is, the switch7receives, from the control unit200, instructions related to which of the first to fourth acoustic wave filters1to4will be brought into the ON states and which of the first to fourth acoustic wave filters1to4will be brought into the OFF states.

Based on the instructions from the control unit200, the switch7switches the ON/OFF state of the first to fourth acoustic wave filters1to4. More specifically, the switch7selectively switches the ON/OFF state of the first to fourth acoustic wave filters1to4between the first state illustrated inFIG. 3Aand the second state illustrated inFIG. 3B. Through the operation described above, two of the first to fourth acoustic wave filters1to4are able to be electrically connected to the antenna300.

As described above, in the composite electronic component10according to the first preferred embodiment, the first IDT electrode12of the first acoustic wave filter1and the second IDT electrode22of the second acoustic wave filter2face each other with the hollow space S1interposed therebetween. In this structure, one of the first acoustic wave filter1and the second acoustic wave filter2that face each other is brought into the OFF state by the switch7, thus reducing the capacitive and magnetic coupling between the first acoustic wave filter1and the second acoustic wave filter2that face each other. Thus, interference between the first acoustic wave filter1and the second acoustic wave filter2is able to be reduced or prevented.

In the composite electronic component10according to the first preferred embodiment, the switch7exclusively switches the ON states and the OFF states of the first acoustic wave filter and the second acoustic wave filter2. Thus, the coupling between the first acoustic wave filter1and the second acoustic wave filter2is able to be further reduced. Similarly, the switch7exclusively switches the ON states and the OFF states of the third acoustic wave filter3and the fourth acoustic wave filter4. Thus, the coupling between the third acoustic wave filter3and the fourth acoustic wave filter4is able to be further reduced.

In the composite electronic component10according to the first preferred embodiment, the switch7is mounted in a multilayer electronic component including the first to fourth acoustic wave filters1to4. Thus, the overall width is able to be reduced and, therefore, the size is able to be reduced compared with a case in which the switch7is provided outside the multilayer electronic component.

In the composite electronic component10according to the first preferred embodiment, the switch7is provided between the first acoustic wave filter1and the external connection electrodes6. Thus, the distance between the first functional electrode (first IDT electrode12) and the switch7and the distance between the switch7and the external connection electrodes6is able to be reduced.

In the composite electronic component10according to the first preferred embodiment, the reference potential line831having the reference potential is provided between the first electrode61and the second electrode62to input and output signals and between the pair of signal lines811and821. Thus, the interference between the pair of signal terminals and the interference between the pair of signal lines811and821are able to be reduced.

Modified examples of the first preferred embodiment are described below.

The composite electronic component10is not limited to the structure in which the switch7is mounted in the multilayer electronic component. The composite electronic component10may have a structure in which the switch7is provided separately from the multilayer electronic component.

The composite electronic component10need not include the four acoustic wave filters (first to fourth acoustic wave filters1to4) but may include two acoustic wave filters, for example.

The switch7may include switching portions that are provided for the respective acoustic wave filters. For example, the switch7includes a first switching portion corresponding to the first acoustic wave filter1, a second switching portion corresponding to the second acoustic wave filter2, a third switching portion corresponding to the third acoustic wave filter3, and a fourth switching portion corresponding to the fourth acoustic wave filter4. The first to fourth switching portions operate independently of each other. When the first switching portion and the third switching portion are in ON states, the switch7operates so that the second switching portion and the fourth switching portion are brought into OFF states. When the second switching portion and the fourth switching portion are in ON states, the switch7operates so that the first switching portion and the third switching portion are brought into OFF states.

The composite electronic component10according to the modified examples described above has advantages the same as or similar to those of the composite electronic component10according to the first preferred embodiment.

Second Preferred Embodiment

A composite electronic component10aaccording to a second preferred embodiment of the present invention is different from the composite electronic component10according to the first preferred embodiment (seeFIG. 2) in that the composite electronic component10ahas electrical connections as illustrated inFIG. 5. In the composite electronic component10aaccording to the second preferred embodiment, elements the same as or similar to those of the composite electronic component10according to the first preferred embodiment are represented by the same reference symbols and description thereof is omitted.

The composite electronic component10aaccording to the second preferred embodiment includes a first acoustic wave filter1a, a second acoustic wave filter2a, a third acoustic wave filter3a, a fourth acoustic wave filter4a, and a switch7a. Similarly to the first preferred embodiment, the composite electronic component10afurther includes the spacer layer5(seeFIG. 1A), the plurality of external connection electrodes6(seeFIG. 1A), the plurality of wiring members8(seeFIG. 1A), and the resin member9(seeFIG. 1A).

The first acoustic wave filter1ahas a structure that is the same as or similar to that of the first acoustic wave filter1of the first preferred embodiment. The second acoustic wave filter2ahas a structure the same as or similar to that of the second acoustic wave filter2of the first preferred embodiment. The first acoustic wave filter1aand the second acoustic wave filter2aare electrically connected to different selective terminals of the switch7a.

The third acoustic wave filter3ahas a structure that is the same as or similar to that of the third acoustic wave filter3of the first preferred embodiment. The fourth acoustic wave filter4ahas a structure that is the same as or similar to that of the fourth acoustic wave filter4of the first preferred embodiment. The third acoustic wave filter3aand the fourth acoustic wave filter4aare electrically connected to different selective terminals of the switch7a.

As illustrated inFIG. 5, the switch7aincludes a common terminal71aand a plurality of selective terminals74to77. The common terminal71ais electrically connected to the terminal105connected to the antenna300(seeFIG. 4). The first acoustic wave filter1ais electrically connected to the selective terminal74. The second acoustic wave filter2ais electrically connected to the selective terminal75. The third acoustic wave filter3ais electrically connected to the selective terminal76. The fourth acoustic wave filter4ais electrically connected to the selective terminal77.

The switch7aselects one selective terminal to be electrically connected to the common terminal71afrom the selective terminals74and75and another selective terminal to be electrically connected to the common terminal71afrom the selective terminals76and77. The switch7aoperates so that the selective terminal74and the selective terminal76are electrically connected to the common terminal71asimultaneously. At this time, the switch7aoperates so that the selective terminal75and the selective terminal77are electrically disconnected from the common terminal71a. The switch7aalso operates so that the selective terminal75and the selective terminal77are electrically connected to the common terminal71asimultaneously. At this time, the switch7aoperates so that the selective terminal and the selective terminal76are electrically disconnected from the common terminal71a.

Next, an operation of the composite electronic component10aaccording to the second preferred embodiment is described with reference toFIGS. 6A and 6B.

In the composite electronic component10aaccording to the second preferred embodiment, the ON/OFF state of the first to fourth acoustic wave filters1ato4ais switched between a first state illustrated inFIG. 6Aand a second state illustrated inFIG. 6Bunder control of the switch7a.

In the first state, the common terminal71aand the selective terminals74and77are electrically connected to each other and the common terminal71aand the selective terminals75and76are electrically disconnected from each other. Thus, in the first state, the first acoustic wave filter1aand the fourth acoustic wave filter4aare in ON states and the second acoustic wave filter2athat faces the first acoustic wave filter1ain the first direction D1and the third acoustic wave filter3athat faces the fourth acoustic wave filter4ain the first direction D1are in OFF states. In the first state, one of two acoustic wave filters adjacent to each other in the second direction D2is in an ON state and the other is in an OFF state. Similarly to the first preferred embodiment, the “ON state” refers to a state in which a signal is able to pass through the acoustic wave filter. The “OFF state” refers to a state in which a signal is not able to pass through the acoustic wave filter.

In the second state, the common terminal71aand the selective terminals75and76are electrically connected to each other and the common terminal71aand the selective terminals74and77are electrically disconnected from each other. Thus, in the second state, the first acoustic wave filter1aand the fourth acoustic wave filter4aare in OFF states and the second acoustic wave filter2athat faces the first acoustic wave filter1ain the first direction D1and the third acoustic wave filter3athat faces the fourth acoustic wave filter4ain the first direction D1are in ON states. In the second state, one of two acoustic wave filters adjacent to each other in the second direction D2is in an ON state and the other is in an OFF state similarly to the first state.

As described above, in the composite electronic component10aaccording to the second preferred embodiment, both of the acoustic wave filters that face each other are not in the ON states and both of the adjacent acoustic wave filters are not in the ON states, thus being capable of further reducing the capacitive and magnetic coupling among the first to fourth acoustic wave filters1ato4a. Thus, the interference among the first to fourth acoustic wave filters1ato4ais able to further be reduced or prevented.

As a modified example of the second preferred embodiment, the composite electronic component10ais not limited to the structure in which the switch7ais mounted in the multilayer electronic component similarly to the first preferred embodiment. The composite electronic component10amay have a structure in which the switch7ais provided separately from the multilayer electronic component.

The composite electronic component10aaccording to the modified example has advantages the same as or similar to those of the composite electronic component10aaccording to the second preferred embodiment.

The preferred embodiments and the modified examples described above are merely a portion of various preferred embodiments and modified examples of the present invention. Various changes may be made to the preferred embodiments and the modified examples depending on design or other factors as long as the advantages of the present invention are achieved.

The following aspects are disclosed based on the preferred embodiments and the modified examples described above.

A composite electronic component (10;10a) according to a preferred embodiment of the present invention includes the first acoustic wave filter (1;1a), the second acoustic wave filter (2;2a), the spacer layer (5), and the switch (7;7a). The second acoustic wave filter (2;2a) faces the first acoustic wave filter (1;1a) in the first direction (D1). The spacer layer (5) has a substantially frame shape and is provided between the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) in the first direction (D1). The switch (7;7a) switches the ON state and the OFF state of the first acoustic wave filter (1;1a) and the ON state and the OFF state of the second acoustic wave filter (2;2a). The first acoustic wave filter (1;1a) includes the first support member (first piezoelectric substrate11) and the first functional electrode (first IDT electrode12). The first support member has piezoelectricity at least in a portion thereof. The first functional electrode is provided at the first principal surface (111) of the first support member. The second acoustic wave filter (2;2a) includes the second support member (second piezoelectric substrate21) and the second functional electrode (second IDT electrode22). The second support member has piezoelectricity at least in a portion thereof. The second functional electrode is provided at the second principal surface (211) of the second support member. The hollow space (S1) is defined by the first support member, the second support member, and the spacer layer (5). The first functional electrode and the second functional electrode are located in the hollow space (S1) and face each other in the first direction (D1). The switch (7;7a) brings at least one of the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) into the OFF state.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, one of the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) that face each other is brought into the OFF state by the switch (7;7a), thus being capable of reducing the capacitive and magnetic coupling between the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) that face each other. Thus, the interference between the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) is able to be reduced or prevented.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the switch (7;7a) exclusively switches the ON states and the OFF states of the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) in the first aspect.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the coupling between the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) is able to be further reduced.

A composite electronic component (10a) according to a preferred embodiment of the present invention includes the third acoustic wave filter (3a) and the fourth acoustic wave filter (4a). The fourth acoustic wave filter (4a) faces the third acoustic wave filter (3a) in the first direction (D1). The third acoustic wave filter (3a) includes the third support member (third piezoelectric substrate31) and the third functional electrode (third IDT electrode32). The third support member has piezoelectricity at least in a portion thereof. The third functional electrode is provided at the third principal surface (311) of the third support member. The fourth acoustic wave filter (4a) includes the fourth support member (fourth piezoelectric substrate41) and the fourth functional electrode (fourth IDT electrode42). The fourth support member has piezoelectricity at least in a portion thereof. The fourth functional electrode is provided at the fourth principal surface (411) of the fourth support member. The third functional electrode and the fourth functional electrode are located in the hollow space (S1) and face each other in the first direction (D1). The switch (7a) simultaneously and exclusively switches the ON states and the OFF states of a first group including the first acoustic wave filter (1a) and the fourth acoustic wave filter (4a) and a second group including the second acoustic wave filter (2a) and the third acoustic wave filter (3a).

In a composite electronic component (10a) according to a preferred embodiment of the present invention, both of the acoustic wave filters that face each other are not in the ON states and both of the adjacent acoustic wave filters are not in the ON states, thus being capable of further reducing the capacitive and magnetic coupling among the first to fourth acoustic wave filters (1ato4a). Thus, the interference among the first to fourth acoustic wave filters (1ato4a) is able to be further reduced or prevented.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a) define a multilayer electronic component. The switch (7;7a) is mounted in the multilayer electronic component.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the overall width is able to be reduced and, therefore, the size is able to be reduced compared with the case in which the switch (7;7a) is provided outside the multilayer electronic component.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, a multilayer electronic component includes the external connection electrode (6) described. The switch (7;7a) is provided between the first acoustic wave filter (1;1a) and the external connection electrode (6).

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the distance between the first functional electrode (first IDT electrode12) and the switch (7;7a) and the distance between the switch (7;7a) and the external connection electrode (6) is able to be reduced.

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the switch (7;7a) overlaps the first functional electrode (first IDT electrode12) in plan view in the first direction (D1).

A composite electronic component (10;10a) according to a preferred embodiment of the present invention further includes the pair of signal terminals (first electrode61and second electrode62), the pair of signal lines (811,821), and the reference potential line (831) in any one of the first to sixth aspects. The pair of signal terminals are used to input and output signals that pass through at least the first acoustic wave filter (1;1a) and the second acoustic wave filter (2;2a). The pair of signal lines (811,821) are connected to the pair of signal terminals. The reference potential line (831) has the reference potential and is provided between the pair of signal terminals and between the pair of signal lines (811,821).

In a composite electronic component (10;10a) according to a preferred embodiment of the present invention, the reference potential line (831) having the reference potential is provided between the pair of signal terminals (first electrode61and second electrode62) to input and output signals and between the pair of signal lines (811,821). Thus, the interference between the pair of signal terminals and the interference between the pair of signal lines (811,821) are able to be reduced.