Filter device

Abstract

To provide a filter device capable of improving reliability.SOLUTION: A filter device 1 includes: a first body 50 including inductors L11 to L15 and a capacitor C11; a second body 80 mounted on the first body 50 and including acoustic wave elements 31, 32; a filter circuit 10 including the inductors L11 to L15, the capacitor C11, and the acoustic wave elements 31, 32; and capacitors C1 to C4. The first body 80 further includes a first signal terminal 2 and a second signal terminal 3. The filter circuit 10 is provided between the first signal terminal 2 and the second signal terminal 3 in the circuit configuration. The capacitors C1, C2 are provided on a first path 5 connecting the first signal terminal 2 and the filter circuit 10. The capacitors C3, C4 are provided on a second path 6 connecting the second signal terminal 3 and the filter circuit 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filter device including a main body and components mounted on the main body. [Background technology]

[0002] Filters such as low-pass filters, high-pass filters, and band-pass filters are constructed using multiple resonators. Examples of resonators used in these filters include LC resonators constructed using inductors and capacitors, and acoustic wave resonators constructed using acoustic wave elements. An acoustic wave element is an element that utilizes acoustic waves. Acoustic wave elements include surface acoustic wave elements that utilize surface acoustic waves and bulk acoustic wave elements that utilize bulk acoustic waves.

[0003] For example, Patent Document 1 discloses an acoustic wave filter device including first and second acoustic wave filter chips mounted on a laminated substrate. In this acoustic wave filter device, the first acoustic wave filter chip is provided between an input terminal and a receiving terminal, and the second acoustic wave filter chip is provided between the input terminal and a transmitting terminal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 136472 Summary of the Invention [Problem to be solved by the invention]

[0005] In a filter device using an acoustic wave element, multiple elements may be provided before and after the acoustic wave element. Consider a case where a signal with a frequency lower than the passband of the filter is input as an interference wave to a filter device having a filter section including an acoustic wave element. When the interference wave is input to the multiple elements before and after the filter section, the multiple elements output not only the interference wave but also harmonics with frequencies higher than the interference wave. If the frequency of the harmonics is within the passband of the filter section, the harmonics are superimposed as noise on the signal to be extracted by the filter device.

[0006] Furthermore, a filter device generally has a plurality of terminals. The plurality of terminals includes a plurality of signal terminals used for inputting or outputting signals and at least one ground terminal connected to ground. When the plurality of terminals are electrically connected, a larger current than normal may flow between the plurality of terminals due to electrostatic discharge. In particular, in a filter device using an acoustic wave element, when an acoustic wave element is provided between two electrically connected terminals, the acoustic wave element may be electrostatically damaged due to electrostatic discharge.

[0007] Incidentally, a filter device using an acoustic wave element, such as the acoustic wave filter device disclosed in Patent Document 1, includes a first component including an acoustic wave element and a second component including other components. The first component is mounted on the second component. The above problem is not limited to cases where the first component includes an acoustic wave element, but also applies to cases where the first component includes any element that may be damaged by electrostatic discharge.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a filter device that can improve reliability. [Means for solving the problem]

[0009] The filter device of the present invention includes a first body including a first element, a second body mounted on the first body and including a second element, a filter circuit including the first element and the second element, a first capacitor, and a second capacitor. The first body further includes a first signal terminal and a second signal terminal. The filter circuit is arranged between the first signal terminal and the second signal terminal in terms of circuit configuration. The first capacitor is arranged in a first path connecting the first signal terminal and the filter circuit. The second capacitor is arranged in a second path connecting the second signal terminal and the filter circuit. [Effects of the Invention]

[0010] In the filter device of the present invention, the first capacitor is provided in a first path connecting the first signal terminal and the filter circuit, and the second capacitor is provided in a second path connecting the second signal terminal and the filter circuit, thereby achieving an advantageous effect of improving the reliability of the filter device. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a circuit diagram showing a circuit configuration of a filter device according to an embodiment of the present invention. [Figure 2] 1 is a perspective view showing a filter device according to an embodiment of the present invention; [Figure 3] 1 is a perspective view showing a first main body of a filter device according to an embodiment of the present invention. [Figure 4] 1 is a perspective view showing a first main body of a filter device according to an embodiment of the present invention. [Figure 5] 5 is an explanatory diagram showing the pattern-forming surfaces of the first to third dielectric layers in the first main body shown in FIGS. 2 to 4. FIG. [Figure 6] 5 is an explanatory view showing the pattern-forming surfaces of the fourth to sixth dielectric layers in the first main body shown in FIGS. 2 to 4. FIG. [Figure 7]5 is an explanatory view showing the pattern-forming surfaces of the seventh to fifteenth dielectric layers in the first main body shown in FIGS. 2 to 4. FIG. [Figure 8] 5 is an explanatory diagram showing the pattern-forming surfaces of the 16th to 18th dielectric layers in the first main body shown in FIGS. 2 to 4. FIG. [Figure 9] 5 is an explanatory view showing an electrode formation surface of the 18th dielectric layer in the first main body shown in FIGS. 2 to 4. FIG. [Figure 10] FIG. 2 is a perspective view showing the inside of a first main body according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, with reference to FIG. 1, a schematic configuration of a filter device 1 according to an embodiment of the present invention will be described. The filter device 1 according to this embodiment includes a first signal terminal 2, a second signal terminal 3, and a filter circuit 10 provided between the first signal terminal 2 and the second signal terminal 3 in terms of the circuit configuration. In this embodiment, the filter circuit 10 particularly constitutes a high-pass filter. Note that in this application, the expression "in terms of the circuit configuration" is used to refer to the arrangement on a circuit diagram, rather than the arrangement in a physical configuration.

[0013] Each of the first and second signal terminals 2 and 3 is a signal terminal for inputting or outputting a signal. That is, when a signal is input to the first signal terminal 2, the signal is output from the second signal terminal 3. When a signal is input to the second signal terminal 3, the signal is output from the first signal terminal 2.

[0014] The filter device 1 further includes a first path 5 connecting the first signal terminal 2 and the filter circuit 10, a second path 6 connecting the second signal terminal 3 and the filter circuit 10, a first low-pass filter 20 provided on the first path 5, and a second low-pass filter 30 provided on the second path 6. In this embodiment, in particular, the filter circuit 10 and the first and second low-pass filters 20, 30 are connected in series from the first signal terminal 2 to the second signal terminal 3 in the order of the first low-pass filter 20, the filter circuit 10 (high-pass filter), and the second low-pass filter 30.

[0015] The filter device 1 further includes capacitors C1 and C2 provided on the first path 5, and capacitors C3 and C4 provided on the second path 6. In terms of the circuit configuration, the capacitor C1 is provided between the first signal terminal 2 and the first low-pass filter 20. In terms of the circuit configuration, the capacitor C2 is provided between the first low-pass filter 20 and the filter circuit 10. In terms of the circuit configuration, the capacitor C3 is provided between the filter circuit 10 and the second low-pass filter 30. In terms of the circuit configuration, the capacitor C4 is provided between the second low-pass filter 30 and the second signal terminal 3.

[0016] In this embodiment, the high-pass filter is composed of a filter circuit 10 and capacitors C2 and C3. The filter device 1 is a band-pass filter composed of the filter circuit 10, first and second low-pass filters 20 and 30, and capacitors C2 and C3. The filter device 1 is configured to selectively pass signals of frequencies within a predetermined pass band.

[0017] Next, an example of the circuit configuration of each of the filter circuit 10, the first low-pass filter 20, and the second low-pass filter 30 will be described with reference to FIG. 1. First, the circuit configuration of the filter circuit 10 will be described. The filter circuit 10 includes inductors L11, L12, L13, and L14, and a capacitor C11. Each of the inductors L11 to L14 has a first end and a second end located opposite each other. Hereinafter, the first end and the second end of the inductor L11 will be represented by reference characters L11a and L11b, respectively; the first end and the second end of the inductor L12 will be represented by reference characters L12a and L12b, respectively; the first end and the second end of the inductor L13 will be represented by reference characters L13a and L13b, respectively; and the first end and the second end of the inductor L14 will be represented by reference characters L14a and L14b, respectively.

[0018] A first end L11a of the inductor L11 and a first end L12a of the inductor L12 are connected to each other. A second end L11b of the inductor L11 is connected to the capacitor C2. A second end L12b of the inductor L12 is connected to one end of the capacitor C11.

[0019] A first end L13a of the inductor L13 and a first end L14a of the inductor L14 are connected to each other. A second end L13b of the inductor L13 is connected to the other end of the capacitor C11. A second end L14b of the inductor L14 is connected to the capacitor C3.

[0020] Filter circuit 10 further includes acoustic wave elements 31 and 32 and an inductor L15. Each of acoustic wave elements 31 and 32 may be, for example, a bulk acoustic wave element or a surface acoustic wave element. One end of acoustic wave element 31 is connected to a first end L11a of inductor L11 and a first end L12a of inductor L12. One end of acoustic wave element 32 is connected to a first end L13a of inductor L13 and a first end L14a of inductor L14. The other ends of acoustic wave elements 31 and 32 are connected to one end of inductor L15. The other end of inductor L15 is connected to ground.

[0021] In the circuit configuration, inductor L11 is provided between the first signal terminal 2 and the acoustic wave element 31. Inductor L12 is provided between the second signal terminal 3 and the acoustic wave element 31. Inductor L13 is provided between the first signal terminal 2 and the acoustic wave element 32. Inductor L14 is provided between the second signal terminal 3 and the acoustic wave element 32.

[0022] Each of acoustic wave elements 31 and 32 is electrically connected to ground via inductor L15. In this application, the expression "electrically connected" includes electrical connection via a metal conductor (including an inductor), but does not include connection via a capacitor. Because capacitors C1 and C2 are interposed between acoustic wave element 31 and first signal terminal 2, acoustic wave element 31 is not electrically connected to first signal terminal 2. Furthermore, because capacitors C3, C4, and C11 are interposed between acoustic wave element 31 and second signal terminal 3, acoustic wave element 31 is not electrically connected to second signal terminal 3. Furthermore, because capacitors C1, C2, and C11 are interposed between acoustic wave element 32 and first signal terminal 2, acoustic wave element 32 is not electrically connected to first signal terminal 2. Furthermore, since capacitors C3 and C4 are interposed between acoustic wave element 32 and second signal terminal 3, acoustic wave element 32 is not electrically connected to second signal terminal 3.

[0023] Inductors L11 to L15, capacitor C11, and acoustic wave elements 31 and 32 are configured to form a high-pass filter.

[0024] Next, a description will be given of the circuit configuration of the first low-pass filter 20. The first low-pass filter 20 includes an inductor L21 and capacitors C21 and C22. One end of the inductor L21 is connected to the capacitor C1. The other end of the inductor L21 is connected to the capacitor C2.

[0025] The capacitor C21 is connected in parallel to the inductor L21. One end of the capacitor C22 is connected to the other end of the inductor L21. The other end of the capacitor C22 is connected to ground.

[0026] Next, the circuit configuration of the second low-pass filter 30 will be described. The second low-pass filter 30 includes an inductor L31 and capacitors C31 and C32. One end of the inductor L31 is connected to the capacitor C3. The other end of the inductor L31 is connected to the capacitor C4.

[0027] The capacitor C31 is connected in parallel to the inductor L31. One end of the capacitor C32 is connected to one end of the inductor L31. The other end of the capacitor C32 is connected to ground.

[0028] Next, the connection relationship of the capacitors C1 to C4 will be described. One end of the capacitor C1 is connected to the first signal terminal 2. The other end of the capacitor C1 is connected to one end of the inductor L21. One end of the capacitor C2 is connected to the other end of the inductor L21. The other end of the capacitor C2 is connected to the second end L11b of the inductor L11.

[0029] One end of the capacitor C3 is connected to the second end L14b of the inductor L14. The other end of the capacitor C3 is connected to one end of the inductor L31. One end of the capacitor C4 is connected to the other end of the inductor L31. The other end of the capacitor C4 is connected to the second signal terminal 3.

[0030] Next, other configurations of the filter device 1 will be described with reference to Fig. 2 to Fig. 4. Fig. 2 is a perspective view showing the filter device 1. Fig. 3 and Fig. 4 are perspective views showing the first main body of the filter device 1.

[0031] The filter device 1 according to this embodiment includes a first body 50 and a second body 80 mounted on the first body 50. The first body 50 is formed of a laminate including a plurality of laminated dielectric layers and a plurality of conductors (a plurality of conductor layers and a plurality of through holes). Each of the plurality of dielectric layers is formed of a dielectric material. For example, low-temperature co-fired ceramics (LTCC) is used as the dielectric material.

[0032] First body 50 includes at least one first element. Second body 80 includes at least one second element. Filter device 1 includes a circuit including at least one first element and at least one second element. In the present embodiment, first body 50 includes inductors L11 to L15 and capacitor C11 shown in FIG. 1 as at least one first element. Second body 80 includes acoustic wave elements 31 and 32 shown in FIG. 1 as at least one second element. Filter device 1 includes filter circuit 10 including inductors L11 to L15, capacitor C11, and acoustic wave elements 31 and 32 as the circuit.

[0033] First body 50 further includes inductors L21 and L31 and capacitors C1 to C4, C21, C22, C31, and C32 shown in Fig. 1. Inductors L11 to L15, L21, and L31 and capacitors C1 to C4, C11, C21, C22, C31, and C32 are provided inside first body 50, which is a laminate, and are configured using multiple dielectric layers and multiple conductors. Acoustic wave elements 31 and 32 are mounted on first body 50, which is a laminate.

[0034] The first body 50 has a first surface 50A and a second surface 50B located at both ends in the stacking direction T of the multiple dielectric layers, and four side surfaces 50C to 50F connecting the first surface 50A and the second surface 50B. The side surfaces 50C and 50D face in opposite directions from each other, and the side surfaces 50E and 50F also face in opposite directions from each other. The side surfaces 50C to 50F are perpendicular to the first surface 50A and the second surface 50B.

[0035] Here, the X direction, Y direction, and Z direction are defined as shown in FIGS. 2 to 4. The X direction, Y direction, and Z direction are perpendicular to each other. In this embodiment, a direction parallel to the stacking direction T is defined as the Z direction. The direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction. The expression "when viewed from a predetermined direction (for example, the Z direction)" means that the object is viewed from a position away in the predetermined direction or in a direction parallel to the predetermined direction.

[0036] As shown in Figures 2 to 4, the first surface 50A is located at the end of the first main body 50 in the Z direction. The first surface 50A is both the top surface of the first main body 50 and the mounting surface for mounting the second main body 80. The second surface 50B is located at the end of the first main body 50 in the -Z direction. The second surface 50B is also the bottom surface of the first main body 50. Figure 3 shows the first main body 50 as viewed from the first surface 50A side. Figure 4 shows the first main body 50 as viewed from the second surface 50B side.

[0037] The side surface 50C is located at the end of the first main body 50 in the -X direction. The side surface 50D is located at the end of the first main body 50 in the X direction. The side surface 50E is located at the end of the first main body 50 in the -Y direction. The side surface 50F is located at the end of the first main body 50 in the Y direction.

[0038] The first body 50 further includes a plurality of electrodes 111, 112, 113, 114, 115, 116, 117, 118, and 119 provided on the second surface 50B of the first body 50. The electrodes 111, 112, and 113 are arranged in this order in the X direction at positions closer to the side surface 50E than to the side surface 50F. The electrodes 115, 116, and 117 are arranged in this order in the -X direction at positions closer to the side surface 50F than to the side surface 50E.

[0039] Electrode 114 is disposed between electrode 113 and electrode 115. Electrode 118 is disposed between electrode 111 and electrode 117. Electrode 119 is disposed between electrode 112 and electrode 116. Electrode 119 is disposed approximately in the center of second surface 50B.

[0040] The electrode 114 corresponds to the first signal terminal 2. The electrode 118 corresponds to the second signal terminal 3. Therefore, the first and second signal terminals 2 and 3 are provided on the second surface 50B of the first body 50. Each of the electrodes 111, 112, 113, 115, 116, 117, and 119 is connected to ground.

[0041] The first body 50 further includes a plurality of electrodes 121, 122, 123, and 124 provided on the first surface 50A of the first body 50. The electrodes 121 and 122 are arranged in this order in the -X direction at positions closer to the side surface 50F than to the side surface 50E. The electrodes 123 and 124 are arranged in this order in the -X direction at positions further ahead of the electrodes 121 and 122 in the Y direction.

[0042] The second body 80 further includes four electrodes 81, 82, 83, and 84. When the second body 80 is mounted on the first body 50, the four electrodes 81 to 84 face the electrodes 121 to 124 of the first body 50, respectively. The four electrodes 81 to 84 are physically connected to the electrodes 121 to 124 by, for example, solder bumps 7.

[0043] The filter device 1 further includes a sealing portion (not shown) that seals the second main body 80. The sealing portion covers the periphery of the second main body 80 and at least a part of the first surface 50A of the first main body 50. The sealing portion may also cover the side surfaces 50C to 50F of the first main body 50. The sealing portion is made of, for example, resin.

[0044] Next, an example of the plurality of dielectric layers, the plurality of conductor layers, and the plurality of through holes that make up the first main body 50 will be described with reference to Figures 5(a) to 9. In this example, the first main body 50 includes 18 laminated dielectric layers. Hereinafter, these 18 dielectric layers will be referred to as the 1st to 18th dielectric layers, in order from the bottom up. The 1st to 18th dielectric layers will be denoted by reference numerals 51 to 68.

[0045] In Figures 5(a) to 8(c), multiple circles represent multiple through holes. Multiple through holes are formed in each of the dielectric layers 51 to 68. The multiple through holes are formed by filling holes for the through holes with conductive paste. Each of the multiple through holes is connected to an electrode, a conductive layer, or another through hole.

[0046] 5(a) to 8(c), specific through holes among the plurality of through holes are assigned reference numerals. The connection relationship between each of the specific through holes and electrodes, conductor layers, or other through holes is explained with reference to the state in which the first to eighteenth dielectric layers 51 to 68 are stacked.

[0047] FIG. 5(a) shows the pattern-formed surface of the first dielectric layer 51. Electrodes 111 to 119 are formed on the pattern-formed surface of the dielectric layer 51. In FIG. 5(a), the through-hole labeled 51T7 is connected to the electrode 116. In the following description, the through-hole labeled 51T7 will be simply referred to as the through-hole 51T7. Furthermore, through-holes labeled with other symbols than the through-hole 51T7 will also be referred to in the same manner as the through-hole 51T7.

[0048] 5(b) shows the pattern-formed surface of the second dielectric layer 52. A conductor layer 521 is formed on the pattern-formed surface of the dielectric layer 52. The through-hole 51T7 and the through-holes 52T7a and 52T7b shown in FIG.

[0049] Fig. 5(c) shows the pattern formation surface of the third dielectric layer 53. Conductor layers 531 and 532 are formed on the pattern formation surface of the dielectric layer 53. The through holes 52T7a and 52T7b are connected to the through holes 53T7a and 53T7b shown in Fig. 5(c), respectively.

[0050] Fig. 6(a) shows the pattern formation surface of the fourth dielectric layer 54. Conductor layers 541, 542, 543, and 544 are formed on the pattern formation surface of the dielectric layer 54. The through holes 54T1a and 54T2a shown in Fig. 6(a) are connected to the conductor layers 541 and 544, respectively. The through holes 53T7a and 53T7b are connected to the through holes 54T7a and 54T7b shown in Fig. 6(a), respectively.

[0051] Fig. 6(b) shows the pattern formation surface of the fifth dielectric layer 55. Conductor layers 551, 552, 553, and 554 are formed on the pattern formation surface of the dielectric layer 55. Conductor layer 551 is connected to conductor layer 552. Conductor layer 553 is connected to conductor layer 554. In Fig. 6(b), the boundary between conductor layer 551 and conductor layer 552 and the boundary between conductor layer 553 and conductor layer 554 are indicated by dotted lines.

[0052] The through holes 55T1b and 55T2b shown in Fig. 6(b) are respectively connected to the conductor layers 552 and 554. The through holes 54T1a, 54T2a, 54T7a, and 54T7b are respectively connected to the through holes 55T1a, 55T2a, 55T7a, and 55T7b shown in Fig. 6(b).

[0053] FIG. 6(c) shows the pattern-formed surface of the sixth dielectric layer 56. Conductor layers 561, 562, 563, and 564 are formed on the pattern-formed surface of the dielectric layer 56. The through-hole 55T1a and the through-hole 56T1a shown in FIG. 6(c) are connected to the conductor layer 562. The through-hole 55T2a and the through-hole 56T2a shown in FIG. 6(c) are connected to the conductor layer 564. The through-holes 55T1b, 55T2b, 55T7a, and 55T7b are connected to the through-holes 56T1b, 56T2b, 56T7a, and 56T7b shown in FIG. 6(c), respectively.

[0054] 7(a) shows the pattern-forming surfaces of the seventh to thirteenth dielectric layers 57 to 63. Through holes 56T1a, 56T1b, 56T2a, 56T2b, 56T7a, and 56T7b are respectively connected to through holes 57T1a, 57T1b, 57T2a, 57T2b, 57T7a, and 57T7b formed in the dielectric layer 57. Furthermore, in the dielectric layers 57 to 63, adjacent through holes with the same reference numerals are connected to each other.

[0055] 7(b) shows the pattern formation surface of the 14th dielectric layer 64. A conductor layer 641 is formed on the pattern formation surface of the dielectric layer 64. Through holes 57T1a, 57T1b, 57T2a, 57T2b, 57T7a, and 57T7b formed in the dielectric layer 63 are connected to through holes 64T1a, 64T1b, 64T2a, 64T2b, 64T7a, and 64T7b shown in FIG. 7(b), respectively.

[0056] FIG. 7(c) shows the pattern formation surface of the 15th dielectric layer 65. Conductor layers 651, 652, 653, and 654 for inductors are formed on the pattern formation surface of the dielectric layer 65. The conductor layer 651 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 651. The through-hole 65T3 shown in FIG. 7(c) is connected to a portion of the conductor layer 651 near the first end. The conductor layer 652 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 652. The through-hole 65T4 shown in FIG. 7(c) is connected to a portion of the conductor layer 652 near the first end.

[0057] The conductor layer 653 has a first end and a second end located opposite to each other in the longitudinal direction of the conductor layer 653. The through-hole 65T5 shown in FIG. 7(c) is connected to a portion of the conductor layer 653 near the first end. The conductor layer 654 has a first end and a second end located opposite to each other in the longitudinal direction of the conductor layer 654. The through-hole 65T6 shown in FIG. 7(c) is connected to a portion of the conductor layer 654 near the first end.

[0058] The through holes 64T1a, 64T1b, 64T2a, 64T2b, 64T7a, and 64T7b are connected to the through holes 65T1a, 65T1b, 65T2a, 65T2b, 65T7a, and 65T7b shown in FIG. 7(c), respectively.

[0059] FIG. 8(a) shows the pattern formation surface of the 16th dielectric layer 66. Inductor conductor layers 661, 662, 663, and 664 are formed on the pattern formation surface of the dielectric layer 66. The conductor layer 661 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 661. The through-hole 66T3 shown in FIG. 8(a) is connected to a portion of the conductor layer 661 near the first end. The through-hole 65T3 is connected to a portion of the conductor layer 661 near the second end. The conductor layer 662 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 662. The through-hole 66T4 shown in FIG. 8(a) is connected to a portion of the conductor layer 662 near the first end. The through-hole 65T4 is connected to a portion of the conductor layer 662 near the second end.

[0060] The conductor layer 663 has a first end and a second end located opposite to each other in the longitudinal direction of the conductor layer 663. The through-hole 66T5 shown in FIG. 8(a) is connected to a portion of the conductor layer 663 near the first end. The through-hole 65T5 is connected to a portion of the conductor layer 663 near the second end. The conductor layer 664 has a first end and a second end located opposite to each other in the longitudinal direction of the conductor layer 664. The through-hole 66T6 shown in FIG. 8(a) is connected to a portion of the conductor layer 664 near the first end. The through-hole 65T6 is connected to a portion of the conductor layer 664 near the second end.

[0061] The through holes 65T1a, 65T1b, 65T2a, 65T2b, 65T7a, and 65T7b are connected to the through holes 66T1a, 66T1b, 66T2a, 66T2b, 66T7a, and 66T7b shown in FIG. 8(a), respectively.

[0062] 8(b) shows the pattern formation surface of the 17th dielectric layer 67. On the pattern formation surface of the dielectric layer 67, conductor layers 671, 672, 673, 674, 677, and 678 for inductors and conductor layers 675 and 676 are formed.

[0063] The conductor layer 671 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 671. The conductor layer 672 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 672. The first end of the conductor layer 671 and the first end of the conductor layer 672 are connected to the conductor layer 675. In FIG. 8(b), the boundary between the conductor layer 671 and the conductor layer 675 and the boundary between the conductor layer 672 and the conductor layer 675 are indicated by dotted lines. The through hole 67T3 shown in FIG. 8(b) is connected to the conductor layer 675.

[0064] The through hole 66T3 is connected to a portion of the conductor layer 671 near the second end. The through hole 66T4 is connected to a portion of the conductor layer 672 near the second end.

[0065] The conductor layer 673 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 673. The conductor layer 674 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 674. The first end of the conductor layer 673 and the first end of the conductor layer 674 are connected to the conductor layer 676. In FIG. 8(b), the boundary between the conductor layer 673 and the conductor layer 676 and the boundary between the conductor layer 674 and the conductor layer 676 are indicated by dotted lines. The through hole 67T4 shown in FIG. 8(b) is connected to the conductor layer 676.

[0066] The through hole 66T5 is connected to a portion of the conductor layer 673 near the second end. The through hole 66T6 is connected to a portion of the conductor layer 674 near the second end.

[0067] The conductor layer 677 has a first end and a second end located on opposite sides in the longitudinal direction of the conductor layer 677. The through-hole 66T1a is connected to a portion of the conductor layer 677 near the first end. The through-hole 66T1b is connected to a portion of the conductor layer 677 near the second end.

[0068] The conductor layer 678 has a first end and a second end located opposite each other in the longitudinal direction of the conductor layer 678. The through-hole 66T2a is connected to a portion of the conductor layer 678 near the first end. The through-hole 66T2b is connected to a portion of the conductor layer 678 near the second end.

[0069] The through holes 66T7a and 66T7b are connected to the through holes 67T7a and 67T7b shown in FIG. 8(b), respectively.

[0070] Fig. 8(c) shows the patterned surface of the 18th dielectric layer 68. The through holes 67T3, 67T4, 67T7a, and 67T7b are connected to the through holes 68T3, 68T4, 68T7a, and 68T7b shown in Fig. 8(c), respectively.

[0071] 9 shows the surface of the 18th dielectric layer 68 opposite to the pattern-forming surface. Hereinafter, the surface of the dielectric layer 68 opposite to the pattern-forming surface will be referred to as the electrode-forming surface of the dielectric layer 68. Electrodes 121, 122, 123, and 124 are formed on the electrode-forming surface of the dielectric layer 68. Through holes 68T3, 68T4, 68T7a, and 68T7b are connected to the electrodes 121, 122, 123, and 124, respectively.

[0072] The first body 50 is constructed by stacking the first to eighteenth dielectric layers 51 to 68 so that the pattern-forming surface of the first dielectric layer 51 becomes the second surface 50B of the first body 50, and the electrode-forming surface of the eighteenth dielectric layer 68 becomes the first surface 50A of the first body 50.

[0073] Each of the multiple through holes shown in Figures 5(a) to 8(c) is connected to a conductor layer that overlaps it in the stacking direction T when the 1st to 18th dielectric layers 51 to 68 are stacked, or to another through hole that overlaps it in the stacking direction T. Furthermore, of the multiple through holes shown in Figures 5(a) to 8(c), a through hole located within an electrode or a conductor layer is connected to that electrode or that conductor layer.

[0074] Fig. 10 shows the inside of the first main body 50, which is configured by laminating the 1st to 18th dielectric layers 51 to 68. As shown in Fig. 10, inside the first main body 50, the multiple conductor layers and multiple through holes shown in Figs. 5(a) to 9 are laminated.

[0075] The following describes the correspondence between the circuit components of the filter device 1 shown in FIG. 1 and the internal components of the first main body 50 shown in FIGS. 5(a) to 9.

[0076] First, a description will be given of the filter circuit 10. The inductor L11 is formed by inductor conductor layers 651, 661, and 671 and through holes 65T3 and 66T3. The inductor L12 is formed by inductor conductor layers 652, 662, and 672 and through holes 65T4 and 66T4.

[0077] The inductor L13 is formed by inductor conductor layers 653, 663, and 673 and through holes 65T5 and 66T5. The inductor L14 is formed by inductor conductor layers 654, 664, and 674 and through holes 65T6 and 66T6.

[0078] The inductor L15 is formed by a through hole 51T7. The capacitor C11 is formed by conductor layers 641, 652, and 653, and a dielectric layer 64 between these conductor layers.

[0079] Next, we will explain the first low-pass filter 20. The inductor L21 is composed of an inductor conductor layer 677, a conductor layer 562, and through holes 54T1a, 55T1a, 55T1b, 56T1a, 56T1b, 57T1a, 57T1b, 64T1a, 64T1b, 65T1a, 65T1b, 66T1a, and 66T1b.

[0080] Capacitor C21 is composed of conductor layers 541 and 551 and a dielectric layer 54 between these conductor layers. Capacitor C22 is composed of conductor layers 542 and 552 and a dielectric layer 54 between these conductor layers.

[0081] Next, we will explain the second low-pass filter 30. The inductor L31 is composed of an inductor conductor layer 678, a conductor layer 564, and through holes 54T2a, 55T2a, 55T2b, 56T2a, 56T2b, 57T2a, 57T2b, 64T2a, 64T2b, 65T2a, 65T2b, 66T2a, and 66T2b.

[0082] Capacitor C31 is composed of conductor layers 544 and 553 and a dielectric layer 54 between these conductor layers. Capacitor C32 is composed of conductor layers 543 and 554 and a dielectric layer 54 between these conductor layers.

[0083] Next, capacitors C1 to C4 will be described. Capacitor C1 is composed of conductor layers 531 and 541 and a dielectric layer 53 between these conductor layers. Capacitor C2 is composed of conductor layers 551 and 561 and a dielectric layer 55 between these conductor layers. Capacitor C3 is composed of conductor layers 553 and 563 and a dielectric layer 55 between these conductor layers. Capacitor C4 is composed of conductor layers 532 and 544 and a dielectric layer 53 between these conductor layers.

[0084] Next, a description will be given of features related to acoustic wave elements 31 and 32. One end of acoustic wave element 31 is connected to conductor layer 671 constituting inductor L11 and conductor layer 672 constituting inductor L12 via conductor layer 675, through holes 67T3 and 68T3, and electrodes 121 and 81. The other end of acoustic wave element 31 is connected to through hole 51T7 constituting inductor L15 via conductor layer 521, through holes 52T7a, 53T7a, 54T7a, 55T7a, 56T7a, 57T7a, 64T7a, 65T7a, 66T7a, 67T7a, and 68T7a, and electrodes 123 and 83.

[0085] Here, a columnar structure formed by connecting multiple through holes in series is referred to as a columnar conductor. The columnar conductor extends in a direction parallel to the stacking direction T. Columnar conductor T7a shown in FIG. 10 is formed by through holes 52T7a, 53T7a, 54T7a, 55T7a, 56T7a, 57T7a, 64T7a, 65T7a, 66T7a, 67T7a, and 68T7a. The other end of acoustic wave element 31 is connected to through hole 51T7, which constitutes inductor L15, via conductor layer 521, columnar conductor T7a, and electrodes 123 and 83.

[0086] One end of acoustic wave element 32 is connected to conductor layer 673 constituting inductor L13 and conductor layer 674 constituting inductor L14 via conductor layer 676, through holes 67T4 and 68T4, and electrodes 122 and 82. Pillar conductor T7b shown in FIG. 10 is composed of through holes 52T7b, 53T7b, 54T7b, 55T7b, 56T7b, 57T7b, 64T7b, 65T7b, 66T7b, 67T7b, and 68T7b. The other end of acoustic wave element 32 is connected to through hole 51T7 constituting inductor L15 via conductor layer 521, pillar conductor T7b, and electrodes 124 and 84.

[0087] Next, the operation and effect of the filter device 1 according to this embodiment will be described. In this embodiment, capacitors C1 and C2 are provided on the first path 5 connecting the first signal terminal 2 and the filter circuit 10, and capacitors C3 and C4 are provided on the second path 6 connecting the second signal terminal 3 and the filter circuit 10. As a result, this embodiment can remove low-frequency signals passing through the first and second paths 5 and 6. As a result, this embodiment can prevent noise caused by low frequencies from being superimposed on signals to be extracted by the filter device 1.

[0088] In this embodiment, each of acoustic wave elements 31 and 32 is electrically connected to ground via inductor L15. Particularly in this embodiment, each of acoustic wave elements 31 and 32 is electrically connected to ground only via a path that passes through inductor L15. Furthermore, in this embodiment, each of acoustic wave elements 31 and 32 is not electrically connected to first and second signal terminals 2 and 3. Particularly in this embodiment, first signal terminal 2 and second signal terminal 3 are not electrically connected to each other, and electrode 114 corresponding to first signal terminal 2 and electrode 118 corresponding to second signal terminal 3 are not electrically connected to other electrodes. For these reasons, in this embodiment, even if static electricity is discharged near filter device 1 and a voltage is applied to electrodes 111 to 119, no current flows through acoustic wave elements 31 and 32.

[0089] As described above, according to this embodiment, the reliability of the filter device 1 can be improved.

[0090] In this embodiment, a first low-pass filter 20 is provided on the first path 5, and a second low-pass filter 30 is provided on the second path 6. When a signal is input to the filter circuit 10, the filter circuit 10 outputs not only the signal but also harmonics having a higher frequency than the signal. According to this embodiment, the harmonics can be removed by the first and second low-pass filters 20 and 30. This also contributes to improving the reliability of the filter device 1 according to this embodiment.

[0091] In this embodiment, the capacitor C2 is connected in series with the inductor L11 of the filter circuit 10. The capacitor C2 and the inductor L11 form a series LC resonator. Generally, a filter circuit using an acoustic wave element is suitable for achieving a bandpass attenuation characteristic that changes sharply in a frequency range close to the pass band. However, a filter circuit using an acoustic wave element has a problem in that it is difficult to achieve a sufficient bandwidth. In contrast, according to this embodiment, the series LC resonator formed by the capacitor C2 and the inductor L11 makes it possible to widen the pass band.

[0092] Similarly, the capacitor C3 is connected in series to the inductor L14 of the filter circuit 10. The capacitor C3 and the inductor L14 form a series LC resonator. According to this embodiment, the series LC resonator formed by the capacitor C3 and the inductor L14 can widen the pass band.

[0093] As described above, in this embodiment, capacitors C2 and C3 have the functions of preventing noise caused by low frequencies from being superimposed on the signal to be extracted by filter device 1, preventing current caused by static electricity from flowing through elastic wave elements 31 and 32, and widening the pass band.

[0094] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the filter device of the present invention is not limited to a band-pass filter, and can be applied to other filter devices such as low-pass filters and high-pass filters, and electronic components including multiple resonators, such as a branching filter that separates multiple signals of different frequency bands.

[0095] Second body 80 may include only one acoustic wave element, or may include three or more. Second body 80 may include any passive element such as a capacitor in addition to acoustic wave elements 31 and 32. In this case, the passive element may be connected to acoustic wave element 31 or 32. Second body 80 may include any active element including a semiconductor such as a high-frequency switch instead of or in addition to acoustic wave elements 31 and 32.

[0096] Furthermore, two or more low-pass filters may be provided in each of the first and second paths 5 and 6. Furthermore, three or more capacitors may be provided in each of the first and second paths 5 and 6.

[0097] As described above, the filter device of the present invention includes a first body including a first element, a second body mounted on the first body and including a second element, a filter circuit including the first element and the second element, a first capacitor, and a second capacitor. The first body further includes a first signal terminal and a second signal terminal. The filter circuit is arranged between the first signal terminal and the second signal terminal in terms of circuit configuration. The first capacitor is arranged in a first path connecting the first signal terminal and the filter circuit. The second capacitor is arranged in a second path connecting the second signal terminal and the filter circuit.

[0098] In the filter device of the present invention, the first capacitor and the second capacitor may be included in the first body.

[0099] In the filter device of the present invention, the filter circuit may constitute a high-pass filter, and the second element may be connected to ground.

[0100] The filter device of the present invention may further include a first low-pass filter provided on the first path. The first capacitor may be provided between the filter circuit and the first low-pass filter in terms of the circuit configuration. The filter device of the present invention may further include a second low-pass filter provided on the second path. The second capacitor may be provided between the filter circuit and the second low-pass filter in terms of the circuit configuration.

[0101] In the filter device of the present invention, the first element may be an inductor. The inductor may be connected in series to one of the first capacitor and the second capacitor. The inductor and the one capacitor may form an LC resonator.

[0102] In the filter device of the present invention, the second element may be an acoustic wave element. [Explanation of symbols]

[0103] 1...filter device, 2...first signal terminal, 3...second signal terminal, 5...first path, 6...second path, 7...solder bump, 10...filter circuit, 20...first low-pass filter, 30...second low-pass filter, 31, 32...acoustic wave element, 50...first body, 50A...first surface, 50B...second surface, 50C-50F...side surface, 51-68...dielectric layer, 80...second body, 81-84, 111-119, 121-124...electrodes, C1-C4, C11, C21, C22, C31, C32...capacitors, L11-L15, L21, L31...inductors.

Claims

1. a first body including a first element; a second body mounted to the first body and including a second element; a filter circuit including the first element and the second element; a first capacitor; a second capacitor; the first body further includes a first signal terminal and a second signal terminal; the filter circuit is provided between the first signal terminal and the second signal terminal in terms of circuit configuration; the first capacitor is provided on a first path connecting the first signal terminal and the filter circuit; The filter device according to claim 1, wherein the second capacitor is provided on a second path connecting the second signal terminal and the filter circuit.

2. 2. The filter device according to claim 1, wherein the first capacitor and the second capacitor are included in the first body.

3. 2. The filter device according to claim 1, wherein the filter circuit constitutes a high-pass filter.

4. 4. The filter device according to claim 3, wherein the second element is connected to ground.

5. 2. The filter device according to claim 1, further comprising a first low-pass filter provided in the first path.

6. 6. The filter device according to claim 5, wherein the first capacitor is provided between the filter circuit and the first low-pass filter in terms of circuit configuration.

7. 6. The filter device according to claim 5, further comprising a second low-pass filter provided in the second path.

8. 8. The filter device according to claim 7, wherein the second capacitor is provided between the filter circuit and the second low-pass filter in terms of circuit configuration.

9. 2. The filter device according to claim 1, wherein the first element is an inductor.

10. the inductor is connected in series with one of the first capacitor and the second capacitor; 10. The filter device according to claim 9, wherein the inductor and the one of the capacitors form an LC resonator.

11. 11. The filter device according to claim 1, wherein the second element is an acoustic wave element.

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