Patent ID: 12224090

DESCRIPTION OF EMBODIMENTS

(1) First Embodiment

A multilayer varistor of a first embodiment of the present disclosure will be described below with reference to the drawings.

FIG.1is a transparent perspective view of a multilayer varistor1of the first embodiment.FIG.2is a transparent top view of the multilayer varistor1.FIG.3is a sectional view of the multilayer varistor1. The multilayer varistor1includes a sintered body11, first external electrodes12, second external electrodes16, third external electrodes20, a first internal electrode13, a second internal electrode17, and a third internal electrode21. The sintered body11, except for the external electrodes of the multilayer varistor1, is in the shape of a rectangular parallelepiped, for example, having a length of 1.6 mm, a width of 0.8 mm, and a height of 0.8 mm Note that in the exterior perspective views such asFIG.3, the outer shape of the sintered body11is shown in the form of a rectangular parallelepiped, but corners of the sintered body11may accordingly be beveled, or the corners of the sintered body11may be rounded.

In the following description, as shown inFIG.1, an X-axis direction parallel to the long side direction of the sintered body11is defined as a left/right direction, a Y-axis direction is defined as a forward/backward direction (depth direction), a Z-axis direction is defined as an up/down direction. Moreover, a positive direction of the X axis is defined as a right side, a positive direction of the Y axis is defined as a forward side, and a positive direction of the Z axis is defined as an upper side. However, these directions are only examples and should not be construed as limiting the directions of the multilayer varistor1in use. In addition, the arrows indicating the respective directions on the drawings are just shown there as an assistant to description and are insubstantial ones.

As shown inFIGS.2and3, the sintered body11has a first end surface S11and a second end surface S12facing each other in a first direction, a first side surface S21and a second side surface S22facing each other in a second direction, and a first principal surface S31and a second principal surface S32facing each other in a third direction. The sintered body11has a stack structure including a plurality of layers LY11to LY14(seeFIG.3) stacked in the third direction and is in the shape of a rectangular parallelepiped having long sides extending in the first direction.

The sintered body11includes a semiconductor ceramic component having a non-linearity resistance characteristic. The sintered body11, for example, includes ZnO as a main component, may include at least one selected from the group consisting of Bi2O3, Co2O3, MnO2, and Sb2O3as an accessory component, and may include at least one selected from the group consisting of Pr6O11, Co2O3, CaCO3, and Cr2O3. In the sintered body11, ZnO is sintered, and the other accessory components are deposited on the grain boundary of ZnO particles, and internal electrodes are formed between the stacked layers. A grain boundary barrier formed between ZnO particles expresses a non-linearity resistance characteristic. The sintered body11is formed, for example, by stacking the four layers LY11to LY14(seeFIG.3) including ZnO as a main component on one another and then sintering the four layers LY11to LY14.

The first external electrodes12are disposed at center parts of long-side side surfaces of the sintered body11. The first external electrodes12are electrically connected to the first internal electrode13. In the present embodiment, the sintered body11is provided with two first external electrodes12, and one of the two first external electrodes12is disposed on the first side surface S21, and the other of the two first external electrodes12is disposed on the second side surface S22. The two first external electrodes12are electrically connected to each other via the first internal electrode13.

The second external electrodes16and the third external electrodes20are disposed on opposing sides of the first external electrodes12. In the present embodiment, the second external electrode16and the third external electrode20are disposed on opposing sides of each of the two first external electrodes12. That is, on the first side surface S21, the second external electrode16and the third external electrode20are disposed on the opposing sides of the first external electrode12, and on the second side surface S22, the second external electrode16and the third external electrode20are disposed on the opposing sides of the first external electrode12. In other words, the sintered body11is provided with two second external electrodes16, and one of the two second external electrodes16is disposed on the first side surface S21, and the other of the two second external electrodes16is disposed on the second side surface S22. Similarly, the sintered body11is provided with two third external electrodes20, and one of the two third external electrodes20is disposed on the first side surface S21, and the other of the two third external electrodes20is disposed on the second side surface S22.

The second internal electrode17electrically connected to the second external electrodes16and the third internal electrode21electrically connected to the third external electrodes20are disposed in the interior of the sintered body11. The second external electrodes16are electrically connected to the second internal electrode17, and the third external electrodes20are electrically connected to the third internal electrode21. That is, the two second external electrodes16provided to the sintered body11are electrically connected to each other via the second internal electrode17, and the two third external electrodes20provided to the sintered body11are electrically connected to each other via the third internal electrode21.

In the present embodiment, the sintered body11includes, for example, the four layers LY11to LY14stacked on one another in the third direction (seeFIG.3). The first internal electrode13is provided by being printed onto, for example, an upper surface (hereinafter also referred to as a first stacking surface SF1) of the layer LY12of the four layers LY11to LY14. The second internal electrode17is provided by being printed onto, for example, an upper surface (hereinafter also referred to as a second stacking surface SF2) of the layer LY13stacked on the layer LY12. The third internal electrode21is provided by being printed onto, for example, an upper surface (hereinafter also referred to as a third stacking surface SF3) of the layer LY11stacked under the layer LY12. In other words, the first internal electrode13is disposed on the first stacking surface SF1in the interior of the sintered body11. The second internal electrode17is disposed on the second stacking surface SF2, which is different from the first stacking surface SF1, in the interior of the sintered body11. The third internal electrode21is disposed on the third stacking surface SF3, which is different from the first stacking surface SF1and the second stacking surface SF2, in the interior of the sintered body11. Thus, in the third direction (up/down direction), the first internal electrode13is disposed between the second internal electrode17and the third internal electrode21.

The first internal electrode13includes a first facing part14and first lead-out parts15. The width of each of the first lead-out parts15is less than the width of the first facing part14. The first lead-out parts15protrude from the first facing part14along the second direction. In the present embodiment, two first lead-out parts15protrude forward and backward from the first facing part14. One of the two first lead-out parts15is electrically connected to the first external electrode12disposed on the first side surface S21, and the other of the two first lead-out parts15is electrically connected to the first external electrode12disposed on the second side surface S22.

The second internal electrode17includes a second facing part18and a second lead-out part19. The width of the second lead-out part19is less than the width of the second facing part18. The second lead-out part19protrudes from the second facing part18along the first direction. In the present embodiment, the second lead-out part19includes a first connection part19B connecting the two second external electrodes16to each other and a first projection19A protruding from the second facing part18along the first direction and connected to the first connection part19B as shown inFIG.2. Here, the first projection19A protrudes, for example, leftward from the second facing part18. The first connection part19B protrudes forward and backward from a left end of the first projection19A to connect the two second external electrodes16to each other.

The third internal electrode21includes a third facing part22and a third lead-out part23. The width of the third lead-out part23is less than the width of the third facing part22. The third lead-out part23protrudes from the third facing part22along the first direction. In the present embodiment, the third lead-out part23protrudes in a direction away from the second lead-out part19, for example, rightward. As shown inFIG.2, the third lead-out part23includes a second connection part23B connecting the two third external electrodes20to each other and a second projection23A protruding from the third facing part22along the first direction and connected to the second connection part23B. Here, the second projection23A protrudes, for example, rightward from the third facing part22. The second connection part23B protrudes forward and backward from a right end of the second projection23A to connect the two third external electrodes20to each other.

Here, the first internal electrode13is disposed on the first stacking surface SF1, the second internal electrode17is disposed on the second stacking surface SF2, and the third internal electrode21is disposed on the third stacking surface SF3, and the first internal electrode13, the second internal electrode17, and the third internal electrode21are each disposed along the second direction.

In this embodiment, the length of the first facing part14is greater than the length of each of the second facing part18and the third facing part22in the first direction. Moreover, the length of the first facing part14is greater than the length of each of the second facing part18and the third facing part22in the second direction. Thus, the area of the first facing part14is larger than the area of each of the second facing part18and the third facing part22. The first facing part14having such a dimension is disposed between the second facing part18and the third facing part22, and therefore, stray capacitance generated between the second facing part18and the third facing part22is reduced, thereby suppressing the crosstalk.

As described above, in the present embodiment, the two first external electrodes12, the two second external electrodes16, and the two third external electrodes20are provided on both side surfaces (the first side surface S21and the second side surface S22) which are long sides when the sintered body11is viewed in a stack direction. In the first direction, each of the first external electrodes12is disposed between the second external electrode16and the third external electrode20and can thus reduce the stray capacitance between the second external electrode16and the third external electrode20. Moreover, the two first external electrodes12are connected to each other via the first lead-out parts15, the two second external electrodes16are connected to each other via the second lead-out part19, and the two third external electrodes20are connected to each other via the third lead-out part23. This configuration enables the first external electrodes12, the second external electrodes16, and the third external electrodes20to be simultaneously formed, and therefore, steps of forming these electrodes are simplified and these electrodes can be stably formed in shape, so that, multilayer varistors1with reduced variations in their characteristics are obtained.

Moreover, the first internal electrode13is disposed between the second internal electrode17and the third internal electrode21in the stack direction of the sintered body11. That is, the first internal electrode13is disposed between the second internal electrode17and the third internal electrode21in the third direction. Specifically, the first facing part14is disposed between the second internal electrode17and the third internal electrode21. In other words, the second facing part18and the third facing part22face each other, and the first internal electrode13is disposed between the second facing part18and the third facing part22. Thus, the first facing part14is disposed between the second facing part18and the third facing part22. The second facing part18faces the first facing part14, and the first facing part14faces the third facing part22, thereby forming a varistor region.

FIG.5is a schematic circuit diagram of a usage example of the multilayer varistor1of the present embodiment. The multilayer varistor1of the present embodiment includes: a first varistor1A formed among the first external electrodes12and the second external electrodes16; and a second varistor1B formed among the first external electrodes12and the third external electrodes20. The circuit diagram inFIG.5shows the multilayer varistor1disposed in the vicinity of a communication IC2configured to perform communication based on a two-wire differential voltage transmission scheme. To the communication IC2, lands of signal lines3and4and a land of a ground line5are connected. The first external electrodes12, which are in a pair and are disposed on the first side surface S21and the second side surface S22, are connected to the land of the ground line5, and the second external electrodes16, which are in a pair and are disposed on the first side surface S21and the second side surface S22, are connected to the land of the signal line3, and the third external electrodes20, which are in a pair and are disposed on the first side surface S21and the second side surface S22, are connected to the land of the signal line4. In such a circuit, for example, when static electricity is superposed on the signal line3and a voltage higher than a prescribed threshold voltage is thus applied to the first varistor1A, the electric resistance of the first varistor1A rapidly decreases, and a current flows through the first varistor1A, and thereby, the communication IC2is protected. Note that the circuit shown inFIG.5is a mere example of a circuit to which the multilayer varistor1is to be applied, and thus, the circuit may accordingly be modified.

In the multilayer varistor1of the present embodiment, the first facing part14is, for example, in the shape of a rectangle of sides 0.46 mm×0.20 mm, and the second facing part18and the third facing part22are each, for example, in the shape of a rectangle of sides 0.40 mm×0.14 mm. Moreover, the first facing part14and the second facing part18face each other with a distance of, for example, 0.035 mm provided therebetween. Similarly, the first facing part14and the third facing part22face each other with a distance of, for example, 0.035 mm provided therebetween. Here, centers of the first, second, and third facing parts are at the same location when viewed in the stack direction. That is, when viewed in the stack direction, the first facing part14extends beyond the second facing part18and the third facing part22by 0.03 mm and entirely covers the peripheral edges of the second facing part18and the third facing part22. In other words, when viewed in the third direction, the first facing part14covers the outer perimeters of the second facing part18and the third facing part22. This prevents the stray capacitance from being generated between the second facing part18and the third facing part22, thereby suppressing the crosstalk. Note that the dimensions described above are mere examples and may accordingly be modified.

The second lead-out part19having a width of, for example, 0.1 mm extends from the second facing part18and is connected to the second external electrodes16. Similarly, the third lead-out part23having a width of, for example, 0.1 mm extends from the third facing part22and is connected to the third external electrodes20. Moreover, the first lead-out part15having a width of, for example, 0.1 mm extends from the first facing part14and is connected to the first external electrodes12. As described above, the internal electrodes are connected via the lead-out parts having smaller widths than the facing parts to the external electrodes, and therefore, the stray capacitance between each second external electrode16and each third external electrode20can be reduced, thereby minimizing the influence on the crosstalk.

Here, in the second direction, the width of the second lead-out part19is desirably less than or equal to 90% of the width of the second facing part18. Further, in the second direction, the width of the second lead-out part19is more desirably less than or equal to 70% of the width of the second facing part18. Similarly, in the second direction, the width of the third lead-out part23is desirably less than or equal to 90% of the width of the third facing part22. Further, in the second direction, the width of the second lead-out part19is more desirably less than or equal to 70% of the width of the second facing part18. Conversely, if the width of the second lead-out part19and the width of the third lead-out part23are respectively greater than 90% of the width of the second facing part18and the width of the third facing part22, the stray capacitance which influences on the crosstalk increases, and thus, such widths are undesirable. Moreover, the width of the second lead-out part19being less than or equal to 90% of the width of the second facing part18in the second direction reduces the stray capacitance generated in the first varistor1A, thereby suppressing the crosstalk from occurring. Further, the width of the third lead-out part23being less than or equal to 90% of the width of the third facing part22in the second direction reduces the stray capacitance generated in the second varistor1B, thereby suppressing the crosstalk from occurring. Furthermore, reducing the absolute value of a difference between the stray capacitance of the first varistor1A and the stray capacitance of the second varistor1B suppresses the crosstalk.

Moreover, in the second direction, the width of the second lead-out part19is desirably greater than or equal to 0.08 mm, and more desirably greater than or equal to 0.1 mm. Similarly, in the second direction, the width of the third lead-out part23is desirably greater than or equal to 0.08 mm, and more desirably greater than or equal to 0.1 mm. If the width of each of the second lead-out part19and the third lead-out part23is less than 0.08 mm, the shape of each of the second lead-out part19and the third lead-out part23tends to become unstable, and thus, connection of the second lead-out part19to the second external electrodes16and connection of the third lead-out part23to the third external electrodes20tend to become unstable. The second lead-out part19and the third lead-out part23each having a width of greater than or equal to 0.08 mm provide the advantage that the shape of each of the second lead-out part19and the third lead-out part23is easily maintained.

Moreover, in the first direction, the width of the first lead-out part15is desirably less than or equal to 90% of the width of the first facing part14. Further, in the first direction, the width of each first lead-out part15is more desirably less than or equal to 70% of the width of the first facing part14. The width of each first lead-out part15being less than or equal to 90% of the width of the first facing part14in the first direction reduces the stray capacitance, thereby suppressing the crosstalk from occurring. Moreover, in the first direction, the width of each first lead-out part15is desirably greater than or equal to 0.08 mm, and more desirably greater than or equal to 0.1 mm. This provides the advantage that the shape of each first lead-out part15is easily maintained.

Moreover, when viewed from above, in the first direction, a size by which the first facing part14extends beyond the outer perimeters of the second facing part18and the third facing part22is desirably greater than or equal to 7.5% and less than or equal to 15% of the long side of each of the second facing part18and the third facing part22. In other words, in the first direction, the length of the first facing part14is preferably greater than or equal to 107.5% and less than or equal to 115% of the length of the second facing part18or the third facing part22. This is because if the amount of protrusion of the first facing part14is less than 7.5% of the long side of each of the second facing part18and the third facing part22, the crosstalk rapidly increases, and if the amount of protrusion is greater than 15% of the long side, misalignment in manufacturing cannot be lessened, which leads to a large capacity difference between the first varistor1A and the second varistor1B. Note that the length of the first facing part14in the first direction is more preferably greater than or equal to 9% and less than or equal to 13.5% of the length of the second facing part18or the third facing part22, and in this case, the crosstalk can be further reduced, and the misalignment in manufacturing can be lessened.

Note that in the second direction, the length of the first facing part14is preferably greater than or equal to 107.5% and less than or equal to 115% of the length of the second facing part18or the third facing part22. This is because if the amount of protrusion of the first facing part14is less than 7.5% of the long side of each of the second facing part18and the third facing part22, the crosstalk rapidly increases, and if the amount of protrusion is greater than 15% of the long side, misalignment in manufacturing cannot be lessened, which leads to a large capacity difference between the first varistor1A and the second varistor1B.

Moreover, in the sintered body11, the volume of a region between the first facing part14and the second facing part18is preferably less than or equal to 5%, and desirably less than or equal to 1% of the total volume of the sintered body11. This is because if the volume is greater than 1%, the entirety of the varistor region is in the proximity of the external electrode, which increases capacitance which influences the crosstalk.

Moreover, the area of the first facing part14is preferably greater than the area of the second facing part18or the third facing part22. In the present embodiment, the first, second, and third internal electrodes13,17, and21are formed such that the area of the first facing part14is greater than the area of the second facing part18and greater than the area of the third facing part22.

Incidentally, the first facing part14of the first internal electrode13is disposed to overlap the second facing part18of the second internal electrode17and the third facing part22of the third internal electrode21in the third direction in the interior of the sintered body11. That is, the first internal electrode13has a superposition region A1(seeFIG.2) superposed on the second internal electrode17and the third internal electrode21in the third direction.

The superposition region A1is a rectangular region whose longitudinal direction extending in the first direction. The length L1of the superposition region A1in the first direction is greater than the length L2of the superposition region A1in the second direction. The length L1in the first direction being greater than the length L2in the second direction reduces the stray capacitance generated between the second facing part18and the third facing part22disposed with the first facing part14being sandwiched therebetween, thereby suppressing the crosstalk.

Moreover, the multilayer varistor1of the present embodiment includes the first varistor1A and the second varistor1B, where the electrostatic capacitance of the first varistor1A and the electrostatic capacitance of the second varistor1B are each preferably less than or equal to 200 pF. Moreover, the difference between the electrostatic capacitance of the first varistor1A and the electrostatic capacitance of the second varistor1B is preferably greater than or equal to −20% and less than or equal to +20% of the electrostatic capacitance of the first varistor1A. This can suppress the cross talk when the multilayer varistor1is connected to the communication IC2as shown inFIG.5, thereby improving the quality of communication.

(2) Second Embodiment

A multilayer varistor1of a second embodiment will be described below with reference toFIGS.6and7.

FIG.6is a transparent perspective view of the multilayer varistor1of the second embodiment.FIG.7is an exterior perspective view of the multilayer varistor1of the second embodiment.

In the multilayer varistor1of the first embodiment, the second external electrodes16and the third external electrodes20are provided on both the side surfaces serving as long sides, whereas in the multilayer varistor1of the second embodiment, a second external electrode16is provided on a first end surface S11of a sintered body11, and a third external electrode20is provided on a second end surface S12of the sintered body11. Note that configurations of a first internal electrode13, a second internal electrode17, and a third internal electrode21are similar to those in the first embodiment, and therefore, common components are denoted by the same reference signs, and the description thereof is omitted.

In the multilayer varistor1of the second embodiment, first external electrodes12are disposed on part of a first side surface S21and part of a second side surface S22.

The second external electrode16is disposed at least part of the first end surface S11. In the present embodiment, the second external electrode16is disposed on the entirety of the first end surface S11and extends from the first end surface S11to part of each of the first side surface S21, the second side surface S22, a first principal surface S31, and a second principal surface S32.

Moreover, the third external electrode20is disposed at least part of the second end surface S12. In the present embodiment, the third external electrode20is disposed on the entirety of the second end surface S12and extends from the second end surface S12to part of each of the first side surface S21, and the second side surface S22, the first principal surface S31, and the second principal surface S32.

Note that in the multilayer varistor1of the second embodiment, the second external electrode16extends from the first end surface S11to the part of each of the first side surface S21, the second side surface S22, the first principal surface S31, and the second principal surface S32, and therefore, the distance between the second external electrode16and each of the first external electrodes12can be larger than that in the multilayer varistor1of the first embodiment, thereby reducing stray capacitance between the second external electrode16and each of the first external electrodes12.

Moreover, in the multilayer varistor1of the second embodiment, the third external electrode20extends from the second end surface S12to the part of each of the first side surface S21, the second side surface S22, the first principal surface S31, and the second principal surface S32, and therefore, the distance between the third external electrode20and each of the first external electrodes12can be larger than that in the multilayer varistor1of the first embodiment, thereby reducing stray capacitance between the third external electrode20and each of the first external electrodes12.

Moreover, the second external electrode16is disposed on the first end surface S11of the sintered body11, and the third external electrode20is disposed on the second end surface S12of the sintered body11, and therefore, the distance between the second external electrode16and the third external electrode20can be greater than that in the multilayer varistor1of the first embodiment, thereby further reducing the influence on the crosstalk.

(3) Third Embodiment

A multilayer varistor1of a third embodiment will be described below with reference toFIGS.8to10.

FIG.8is a transparent perspective view of the multilayer varistor1of the third embodiment.FIG.9is a transparent top view of the multilayer varistor1of the third embodiment.FIG.10is a sectional view of the multilayer varistor1of the third embodiment.

In the multilayer varistor1of the second embodiment, the first facing part14covers the outer perimeters of the second facing part18and the third facing part22, whereas in the third embodiment, part of each of a second facing part18and a third facing part22protrude outside a first facing part14as shown inFIGS.9and10. Note that components except for a first internal electrode13, a second internal electrode17, and a third internal electrode21have similar configurations to those in the multilayer varistor1of the second embodiment, and therefore, the components common to those in the second embodiment are denoted by the same reference signs, and the description thereof is omitted.

The second facing part18has a rectangular shape whose longitudinal direction extending in the first direction. The length of the second facing part18in the first direction is greater than the length of the first facing part14in the first direction, and the length of the second facing part18in the second direction is less than the length of the first facing part14in the second direction.

Similarly, the third facing part22has a rectangular shape whose longitudinal direction extending in the first direction. The length of the third facing part22in the first direction is greater than the length of the first facing part14in the first direction, and the length of the third facing part22in the second direction is less than the length of the first facing part14in the second direction.

The first facing part14and the second facing part18face each other with a prescribed distance provided therebetween, and the first facing part14and the third facing part22face each other with a prescribed distance provided therebetween. The centers of the first facing part14, the second facing part18, and the third facing part22are at the same location when viewed in the stack direction, and the second facing part18and the third facing part22substantially overlap each other when viewed in the stack direction. Moreover, when viewed in the stack direction, the second facing part18has a right end and a left end protruding beyond the first facing part14in the first direction, and the third facing part22has a right end and a left end protruding beyond the first facing part14. The second facing part18is covered with the first facing part14except for the right end and the left end protruding beyond the first facing part14. Similarly, the third facing part22is covered with the first facing part14except for the right end and the left end protruding beyond the first facing part14.

Here, displacement of the internal electrodes caused in steps of printing the internal electrodes, stacking and cutting layers, forming the external electrodes, and the like may lead to displacement of the first internal electrode13in the first direction with respect to the second internal electrode17and the third internal electrode21. Displacement of the first internal electrode13in the first direction with respect to the second internal electrode17and the third internal electrode21may lead to an increased capacity difference of electrostatic capacitance generated between each of first external electrodes12and a second external electrode16from electrostatic capacitance generated between each of the first external electrodes12and a third external electrode20. In the multilayer varistor1of the present embodiment, the second facing part18and the third facing part22protrude on both side of the first facing part14in the first direction, and therefore, even when the first internal electrode13is displaced with respect to the second internal electrode17and the third internal electrode21in the first direction, it is possible to reduce the capacity difference of the electrostatic capacitance generated between each of first external electrodes12and the second external electrode16from the electrostatic capacitance generated between each of the first external electrodes12and the third external electrode20. This provides the advantage that the crosstalk caused due to the capacity difference between a first varistor1A and a second varistor1B can be suppressed.

Table 1 below shows the relationship between the ratio of a longitudinal dimension (length L1) to a transverse dimension (length L2) of a superposition region A1and the capacity difference caused due to dimensional variations. The dimensional variations are variations in dimensions between the internal electrodes or dimensions between the internal electrodes and the external electrodes caused in each of steps of printing the internal electrodes, stacking and cutting layers, forming the external electrodes, and the like. The capacity difference is the absolute value of a difference of stray capacitance generated between the first internal electrode13and the second internal electrode17from stray capacitance generated between the first internal electrode13and the third internal electrode21. In Table 1, capacity differences of Examples 1, 3, and 4 and Comparative Examples 1 and 2 are evaluated, where the capacity difference of Example 2 is 1. Here, a sintered body11is in the shape of a rectangular parallelepiped having a length of 1.6 mm, a width of 0.8 mm, and a height of 0.8 mm, the first facing part14is in the shape of a rectangle having a length of 0.44 mm and a width of 0.22 mm, and the second facing part18and the third facing part22are each in the shape of a rectangle having a length of 0.54 mm and a width of 0.12 mm

TABLE 1L1/L2Capacity DifferenceComparative Example 10.21.62Example 11.31.06Example 23.71.00Example 35.41.07Example 47.51.28Comparative Example 211.21.76

According to the results in Table 1, the ratio of the length L1of the superposition region A1in the first direction to the length L2of a superposition region A1in the second direction is preferably greater than or equal to 1.3 and less than or equal to 7.5. Reducing the difference of the electrostatic capacitance between the first varistor1A and the second varistor1B can improve the quality of communication.

Moreover, Table 2 below shows a relationship between the ratio of the area (area ratio) of the superposition region A1to the area of a first stacking surface SF1of the sintered body11and the capacity difference caused due to dimensional variations. The dimensional variations are, in a similar manner as described above, variations in dimensions between the internal electrodes or dimensions between the internal electrodes and the external electrodes caused in each of steps of printing the internal electrodes, stacking and cutting layers, forming the external electrodes, and the like. The capacity difference is the absolute value of the difference of the stray capacitance generated between the first internal electrode13and the second internal electrode17from the stray capacitance generated between the first internal electrode13and the third internal electrode21. In Table 2, capacity differences of Examples 5 and 6 and Comparative Examples 3 and 4 are evaluated, where the capacity difference of Example 2 is 1. Here, the sintered body11is in the shape of a rectangular parallelepiped having a length of 1.6 mm, a width of 0.8 mm, and a height of 0.8 mm, the first facing part14is in the shape of a rectangle having a length of 0.44 mm and a width of 0.22 mm, and the second facing part18and the third facing part22are each in the shape of a rectangle having a length of 0.54 mm and a width of 0.12 mm

TABLE 2Area RatioCapacity DifferenceComparative Example 30.0200.85Example 50.0240.86Example 20.0401.00Example 60.1611.26Comparative Example 40.3911.63

According to the results in Table 2, the ratio of the area of the superposition region A1to the sectional area of the sintered body11on the first stacking surface SF1is preferably greater than or equal to 0.024 and less than or equal to 0.161. Reducing the difference of the electrostatic capacitance between the first varistor1A and the second varistor1B can improve the quality of communication.

Note that in the multilayer varistor1of the third embodiment, in a similar manner to the multilayer varistor1of each of the first and second embodiments, the first internal electrode13has the superposition region A1overlapping the second internal electrode17and the third internal electrode21in the third direction. Here, on the first stacking surface SF1, the superposition region A1is in a second region A3except for a first region A2on which each of the first external electrodes12, the second external electrode16, and the third external electrode20is projected. This reduces stray capacitance generated be each of the first external electrodes12and the second external electrode16, and stray capacitance generated between each of the first external electrodes12and the third external electrode20, thereby suppressing the crosstalk. Note that the multilayer varistor1of each of the first and second embodiments includes, on the first stacking surface SF1, a superposition region A1in a second region A3except for a first region A2on which each of the first external electrodes12, the second external electrode(s)16, and the third external electrode(s)20is projected, thereby suppressing the cross talk.

Note that the first internal electrode13, the second internal electrode17, and the third internal electrode21of the third embodiment may be applied to the multilayer varistor1of the first embodiment, thereby providing similar advantages to those provided by the multilayer varistor1of the third embodiment.

(4) Variations

Variations of the multilayer varistor of the present disclosure will be described below.

The multilayer varistor1inFIG.1includes one layer including the second internal electrode17and the first internal electrode13facing each other and one layer including the third internal electrode21and the first internal electrode13facing each other. Alternatively, however, a plurality of layers each including the second internal electrode17and the first internal electrode13facing each other and a plurality of layers each including the third internal electrode21and the first internal electrode13facing each other may be provided as shown inFIG.11. In this case, these layers are preferably vertically separated such that the plurality of layers each including the second internal electrode17and the first internal electrode13are disposed, for example, on an upper surface side and the plurality of layers each including the third internal electrode21and the first internal electrode13are disposed, for example, on a lower surface side as shown inFIG.11. This configuration can further suppress the crosstalk. Moreover, increasing a facing area of the second internal electrodes17and the first internal electrodes13and a facing area of the third internal electrodes21and the first internal electrodes13can improve the performance as the varistor.

Note that in the multilayer varistor1of each of the second and third embodiments, a plurality of second internal electrodes17and a plurality of first internal electrodes13may face each other, and/or a plurality of third internal electrodes21and a plurality of first internal electrodes13may face each other.

Moreover, in the multilayer varistor1of the first embodiment, the first external electrodes12, the second external electrodes16, and the third external electrodes20are disposed on both the first side surface S21and the second side surface S22, but the first external electrode12, the second external electrode16, and the third external electrode20may be disposed on at least one of the first side surface S21or the second side surface S22. That is, the first external electrode12, the second external electrode16, and the third external electrode20may be disposed on only the first side surface S21or the second side surface S22.

Moreover, in the embodiments described above, the four layers LY11to LY14are stacked on one another, thereby forming the sintered body11, but the sintered body11is not limited to having a stack structure including four layers. The sintered body11at least has a stack structure including a plurality of layers.

The multilayer varistor1according to the present disclosure has reduced stray capacitance generated between the external electrodes and thus has suppressed crosstalk, and thus, this multilayer varistor1is industrially useful.

REFERENCE SIGNS LIST

1Multilayer Varistor1A First Varistor1B Second Varistor11Sintered Body12First External Electrode13First Internal Electrode14First Facing Part15First Lead-Out Part16Second External Electrode17Second Internal Electrode18Second Facing Part19Second Lead-Out Part19A First Projection19B First Connection Part20Third External Electrode21Third Internal Electrode22Third Facing Part23Third Lead-Out Part23A Second Projection23B Second CouplerA1Superposition RegionA2First RegionA3Second RegionLY11to LY14LayerS11First End SurfaceS12Second End SurfaceS21First Side SurfaceS22Second Side SurfaceS31First Principal SurfaceS32Second Principal SurfaceSF1First Stacking SurfaceSF2Second Stacking SurfaceSF3Third Stacking Surface