Resistor

Abstract

To provide a resistor capable of improving the heat dissipation property.SOLUTION: A resistor A10 includes a first insulator 11 having a first main surface 11A and a first back surface 11B, a resistor 20 disposed on the first main surface 11A, a second insulator 12 covering the resistor 20, a pair of electrodes 40 electrically connected to the resistor 20 on both sides in a first direction x, and a first covering body 30A stacked on the first back surface 11B. The first covering body 30A includes a first layer 31 having conductivity and in contact with the first back surface 11B. The resistor 20 includes a first end surface 20A facing one side in the first direction x. The first insulator 11 includes a third end surface 11C facing the same side as the first end surface 20A in the first direction x, and being flush with the first end surface 20A. Each of the pair of electrodes 40 has a side part 42 including a part extending in a thickness direction z. The side part 42 of any of the pair of electrodes 40 is in contact with the first end surface 20A and the third end surface 11C.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure mainly relates to a resistor used for current detection.

Background Art

[0002] Conventionally, a resistor including a resistor body made of a metal material has been known. The resistor is mainly used for current detection. Patent Document 1 discloses an example of such a resistor. The resistor includes a resistor body and a pair of electrodes connected to both ends of the resistor body.

[0003] When the resistor detects a larger current, the heat generated from the resistor body further increases. If the temperature of the resistor body rises due to this heat, the resistance value of the resistor may vary. Therefore, it is required to improve the heat dissipation of the resistor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above circumstances, an object of the present disclosure is to provide a resistor capable of improving heat dissipation.

Means for Solving the Problems

[0006] The resistor provided by the present disclosure includes a first insulator having a first main surface and a first back surface facing opposite sides in the thickness direction, a resistor disposed on the first main surface, a second insulator covering the resistor, a pair of electrodes electrically connected to the resistor on both sides in a first direction orthogonal to the thickness direction, and a first coating layer laminated on the first back surface. The first coating layer has conductivity and has a first layer in contact with the first back surface. The resistor has a first end face facing one side in the first direction. The first insulator has a third end face facing the same side as the first end face in the first direction and flush with the first end face. Each of the pair of electrodes has a side portion including a portion extending in the thickness direction. The side portion of any one of the pair of electrodes is in contact with the first end face and the third end face.

[0007] Other features and advantages of the present disclosure will become more apparent from the following detailed description based on the accompanying drawings.

Brief Description of the Drawings

[0008]

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Best Mode for Carrying Out the Invention

[0009] A mode for carrying out the present disclosure will be described based on the accompanying drawings.

[0010] 〔First Embodiment〕 Based on FIGS. 1 to 9, the resistor A10 according to the first embodiment of the present disclosure will be described. The resistor A10 targets a shunt resistor used for current detection. The resistance value of the resistor A10 is generally 5 mΩ or more and 220 mΩ or less. The resistor A10 is surface-mounted on wiring boards of various electronic devices. The resistor A10 includes a first insulator 11, a resistor body 20, a second insulator 12, a coating 30, and a pair of electrodes 40. Here, FIG. 2 penetrates the second layer 32 (details will be described later) of the coating 30 for convenience of understanding. FIG. 3 penetrates the first insulator 11 and the coating 30 for convenience of understanding.

[0011] In the description of the resistor A10, for convenience, the thickness direction of the first insulator 11 is referred to as the "thickness direction z". The direction orthogonal to the thickness direction z is referred to as the "first direction x". The direction orthogonal to both the thickness direction z and the first direction x is referred to as the "second direction y". The "thickness direction z", "first direction x", and "second direction y" are also applicable in the description of the resistors A20 to A40 described later. As shown in FIG. 1, the resistor A10 is rectangular when viewed in the thickness direction z. In the resistor A10, the first direction x corresponds to the longitudinal direction of the resistor A10 when viewed from the thickness direction z.

[0012] As shown in FIG. 6, the first insulator 11 has the resistor body 20 disposed thereon. The first insulator 11 is a synthetic resin sheet made of an epoxy resin or the like. The first insulator 11 has electrical insulation and flexibility. The first insulator 11 contains a filler 112 having electrical insulation. The filler 112 is made of a material containing ceramics having a relatively high thermal conductivity, such as alumina (Al2O3) or boron nitride (BN).

[0013] As shown in FIG. 6, the first insulator 11 has a first main surface 11A and a first back surface 11B. The first main surface 11A faces the side where the resistor 20 is located with respect to the first insulator 11 in the thickness direction z. The first back surface 11B faces the side opposite to the first main surface 11A. The thickness of the first insulator 11 (the length from the first main surface 11A to the first back surface 11B in the thickness direction z) is 40 μm or more and 60 μm or less.

[0014] As shown in FIG. 6, the resistor 20 is a passive element disposed on the first main surface 11A of the first insulator 11. As an example of the material of the resistor 20, alloy materials such as copper (Cu)-manganese (Mn)-nickel (Ni) alloy (manganin: registered trademark) or copper-manganese-tin (Sn) alloy (zeranin: registered trademark) can be mentioned. The thickness of the resistor 20 is 50 μm or more and 150 μm or less. As shown in FIGS. 3 and 6, the resistor 20 is provided with a plurality of resistance slits 21 penetrating in the thickness direction z. The plurality of resistance slits 21 are provided to set the resistance value of the resistor 20 to a predetermined value. The plurality of resistance slits 21 extend in the second direction y. Due to the plurality of resistance slits 21, both ends of the resistor 20 in the second direction y are partially open. Due to the plurality of resistance slits 21, when viewed in the thickness direction z, the resistor 20 has a meandering shape with respect to the first direction x. As shown in FIG. 7, the side walls 22 of the plurality of resistance slits 21 are concave toward the inside of the resistor 20.

[0015] As shown in FIGS. 3 to 6, the second insulator 12 covers the resistor 20. The second insulator 12 is a synthetic resin sheet made of an epoxy resin or the like. The second insulator 12 has a second main surface 12A and a second back surface 12B. The second main surface 12A faces the side where the first insulator 11 is located with respect to the second insulator 12 in the thickness direction z. The thickness of the second insulator 12 (the length from the second main surface 12A to the second back surface 12B in the thickness direction z) is 40 μm or more and 60 μm or less. The second main surface 12A is in contact with the surface of the resistor 20. Thus, the resistor 20 is sandwiched between the second main surface 12A and the first main surface 11A of the first insulator 11. The second back surface 12B faces the side opposite to the second main surface 12A. A part of the second back surface 12B is exposed.

[0016] As shown in FIG. 7, a plurality of embedded portions 121 are provided in the second insulator 12. The plurality of embedded portions 121 protrude from the second main surface 12A in the thickness direction z. The plurality of embedded portions 121 are located in the plurality of resistance slits 21 of the resistor 20. In the resistor A10, each of the plurality of embedded portions 121 is in contact with the side wall 22 of the resistance slit 21.

[0017] FIG. 8 shows an example in which both the plurality of embedded portions 121 of the second insulator 12 and the plurality of embedded portions 111 provided in the first insulator 11 are located in the plurality of resistance slits 21 of the resistor 20. The plurality of embedded portions 111 protrude from the first main surface 11A of the first insulator 11 in the thickness direction z. In the resistor A10, each of the plurality of embedded portions 111 is in contact with both the side wall 22 of the resistance slit 21 and the embedded portion 121. Thus, at least a part of either the first insulator 11 or the second insulator 12 is configured to be located in the resistance slit 21.

[0018] As shown in FIG. 6, the covering 30 is laminated on the first back surface 11B of the first insulator 11 in the resistor A10. Here, the covering 30 includes a first covering 30A and a second covering 30B. The first covering 30A refers to the covering 30 laminated on the first insulator 11. The second covering 30B refers to the covering 30 laminated on the second insulator 12. The resistor A10 is configured to include the first covering 30A of the covering 30.

[0019] As shown in FIGS. 5 and 6, the first covering 30A (covering 30) has a first layer 31 and a second layer 32. As shown in FIGS. 2 and 6, the first layer 31 is in contact with the first back surface 11B of the first insulator 11. The first layer 31 has conductivity. The first layer 31 is made of a material containing copper. The material of the first layer 31 is preferably a material having a relatively small electrical resistivity and a relatively large thermal conductivity. The thickness of the first layer 31 is 70 μm or more and 90 μm or less. Therefore, the thickness of the first layer 31 is greater than the thicknesses of the first insulator 11 and the second insulator 12. As shown in FIGS. 1 and 6, the second layer 32 is laminated on the first layer 31. The second layer 32 is a synthetic resin sheet having electrical insulation properties. The second layer 32 can be, for example, a synthetic resin sheet made of a glass epoxy resin.

[0020] As shown in FIGS. 2 and 6, the first layer 31 is provided with a slit 311 penetrating in the thickness direction z. Due to the slit 311, the first layer 31 is divided into a plurality of regions. In addition, both ends of the first layer 31 in the second direction y are partially open. In the resistor A10, when viewed in the thickness direction z, the slit 311 is inclined with respect to the first direction x. When viewed in the thickness direction z, the slit 311 passes through the center C of the first covering 30A. Here, the center C of the first covering 30A refers to the intersection of the diagonal lines of the first covering 30A when viewed in the thickness direction z. As shown in FIG. 7, the side wall 312 of the slit 311 is concave toward the inside of the first layer 31.

[0021] As shown in FIG. 7, the second layer 32 is provided with an embedded portion 321. The embedded portion 321 protrudes in the thickness direction z from the surface of the second layer 32 in contact with the first layer 31. The embedded portion 321 is located in the slit 311 of the first layer 31. Thus, a part of the second layer 32 is configured to be located in the slit 311. In the resistor A10, the embedded portion 321 is in contact with the side wall 312 of the slit 311.

[0022] As shown in FIG. 6, the pair of electrodes 40 are electrically connected to the resistor 20 on both sides in the first direction x. Each of the pair of electrodes 40 includes a base layer 40A and a plating layer 40B. As shown in FIGS. 6 and 7, in the resistor A10, the base layer 40A is in contact with the first insulator 11, the resistor 20, and the second insulator 12. As an example of the material of the base layer 40A, a nickel-chromium (Cr) alloy can be mentioned. The plating layer 40B covers the base layer 40A. In the resistor A10, the plating layer 40B is a metal layer in which copper, nickel, and tin are laminated in order from the portion in contact with the base layer 40A.

[0023] As shown in FIGS. 4 to 6, each of the pair of electrodes 40 has a bottom portion 41 and a side portion 42. Each of the bottom portion 41 and the side portion 42 includes a base layer 40A and a plating layer 40B. The bottom portion 41 is located on the side opposite to the resistor 20 with respect to the second insulator 12 in the thickness direction z. As shown in FIG. 4, the bottom portion 41 overlaps the first main surface 11A of the first insulator 11 when viewed in the thickness direction z. In the resistor A10, the bottom portion 41 is in contact with the second back surface 12B of the second insulator 12.

[0024] As shown in FIGS. 4 to 6, the side portion 42 is connected to the bottom portion 41 and extends in the thickness direction z. As shown in FIG. 7, the resistor 20 has a pair of first end faces 20A facing the first direction x. The pair of side portions 42 are in contact with the pair of first end faces 20A. Thereby, the pair of electrodes 40 are electrically connected to the resistor 20. Further, the second insulator 12 has a pair of second end faces 12C facing the first direction x. The first insulator 11 has a pair of third end faces 11C facing the first direction x. The pair of second end faces 12C and the pair of third end faces 11C are flush with the pair of first end faces 20A. The pair of side portions 42 are also in contact with both the pair of second end faces 12C and the pair of third end faces 11C.

[0025] As shown in Fig. 7, the first covering 30A has a pair of first convex portions 33. The first insulator 11 has a pair of second convex portions 113. The pair of first convex portions 33 and the pair of second convex portions 113 protrude from a pair of first end faces 20A of the resistor 20 in the first direction x. In the resistor A10, the pair of first convex portions 33 are composed of the first layer 31 and the second layer 32. As shown in Fig. 9, the pair of side portions 42 are in contact with both the pair of first convex portions 33 and the pair of second convex portions 113. The plating layer 40B of the pair of side portions 42 is in contact with the portion composed of the first layer 31 among the pair of first convex portions 33.

[0026] Next, an example of the manufacturing method of the resistor A10 will be described with reference to Figs. 10 to 16. Here, the cross-sectional positions shown in Figs. 10 to 16 are the same as the cross-sectional positions shown in Fig. 6.

[0027] First, as shown in Fig. 10, a resistor 82 and a first covering layer 83 are arranged on a first insulator 81 having a main surface 811 and a back surface 812 facing opposite sides in the thickness direction z. The first insulator 81, the resistor 82, and the first covering layer 83 correspond to the first insulator 11, the resistor 20, and the first layer 31 (the first covering 30A) of the resistor A10 in this order. The resistor 82 is arranged on the first insulator 81 by being pressure-bonded to the main surface 811. The first covering layer 83 is arranged on the resistor 82 by being pressure-bonded to the back surface 812. A plurality of resistance slits 821 penetrating in the thickness direction z are provided in the resistor 82. A slit 831 penetrating in the thickness direction z is provided in the first covering layer 83. The plurality of resistance slits 821 and the slit 831 are formed by wet etching.

[0028] Next, as shown in FIG. 11, a second insulator 84 is laminated on the resistor 82. The second insulator 84 corresponds to the second insulator 12 of the resistor A10. The second insulator 84 is laminated by being pressure-bonded to the resistor 82. By this step, a part of the second insulator 84 is located in a plurality of resistor slits 821 of the resistor 82. Also, in this step, a second coating layer 85 is laminated on the first coating layer 83. The second coating layer 85 corresponds to the second layer 32 (first coating body 30A) of the resistor A10. The second coating layer 85 is laminated by being pressure-bonded to the first coating layer 83. By this step, a part of the second coating layer 85 is located in the slit 831 of the first coating layer 83.

[0029] Next, as shown in FIG. 12, a plurality of grooves 881 that are recessed in the thickness direction z from the second insulator 84 are formed. The plurality of grooves 881 are formed along the second direction y. The plurality of grooves 881 are formed using, for example, a dicing blade. By forming the plurality of grooves 881, a part of each of the second insulator 84, the resistor 82, and the first insulator 81 is removed. Among these, the plurality of grooves 881 penetrate the second insulator 84 and the resistor 82 in the thickness direction z. Each of the plurality of grooves 881 has a width b1 (dimension in the first direction x of the groove 881).

[0030] Next, as shown in FIG. 13, a base layer 86 that covers the surfaces of both the second insulator 84 and the plurality of grooves 881 is formed. The base layer 86 corresponds to the base layer 40A of the pair of electrodes 40 of the resistor A10. The base layer 86 is formed by a sputtering method.

[0031] Next, as shown in FIG. 14, a part of the base layer 86 that covers the surface of the second insulator 84 is removed. After forming a mask that covers the base layer 86, wet etching is performed on the portion of the base layer 86 that is not covered by the mask, whereby a part of the base layer 86 is removed. The second insulator 84 is exposed from the portion where the base layer 86 has been removed.

[0032] Next, as shown in FIG. 15, a plurality of slits 882 are formed. The plurality of slits 882 are formed in a lattice pattern along both the first direction x and the second direction y. Among these, the plurality of slits 882 along the second direction y are formed from the base layer 86 covering the bottom of the plurality of grooves 881 in the thickness direction z. The plurality of slits 882 are formed using, for example, a dicing blade. Each of the plurality of slits 882 has a width b2 (dimension in the first direction x of the slit 882). The width b2 is smaller than the width b1 of the groove 881. By this step, the first insulator 81, the resistor 82 laminated on the first insulator 81, the first coating layer 83, the second insulator 84, the second coating layer 85, and the base layer 86 are divided into individual pieces. That is, the formation of the first insulator 11, the second insulator 12, the resistor 20, the first coating body 30A (coating body 30), and the base layer 40A of the pair of electrodes 40 of the resistor A10 is completed.

[0033] Finally, as shown in FIG. 16, a pair of plating layers 40B covering the pair of base layers 40A are formed. The pair of plating layers 40B are formed by electrolytic barrel plating. By this step, the formation of the pair of electrodes 40 of the resistor A10 is completed. Also, by this step, both the pair of first convex portions 33 of the first coating body 30A and the pair of second convex portions 113 of the first insulator 11 are covered with the pair of plating layers 40B. Through the above steps, the resistor A10 is manufactured.

[0034] (First Modified Example) Based on FIG. 17, the resistor A11 according to the first modified example of the resistor A10 will be described. The resistor A11 is an example in which the configurations of the first insulator 11, the first coating body 30A (coating body 30), and the pair of electrodes 40 are different from those of the resistor A10 described above.

[0035] Unlike the resistor A10, the first insulator 11 is not provided with a pair of second convex portions 113. Also, the first layer 31 of the first coating body 30A has a pair of fourth end faces 313 facing the first direction x. The pair of fourth end faces 313 are flush with the pair of third end faces 11C of the first insulator 11. The pair of fourth end faces 313 are in contact with the side portions 42 of the pair of electrodes 40.

[0036] The pair of first convex portions 33 of the first covering 30A is composed of a first layer 31 and a second layer 32. The portions of the pair of first convex portions 33 formed of the first layer 31 protrude from the pair of fourth end faces 313 in the first direction x. The side portions 42 of the pair of electrodes 40 are in contact with the portions of the pair of first convex portions 33 formed of the first layer 31.

[0037] The configuration of the resistor A11 is obtained by making the depth of the plurality of grooves 881 shown in FIG. 12 greater than the depth of the plurality of grooves 881 formed during the manufacture of the resistor A10 in the step of forming the plurality of grooves 881.

[0038] (Second Modified Example) Based on FIG. 18, the resistor A12 according to the second modified example of the resistor A10 will be described. The resistor A12 is an example in which the configuration of the first insulator 11, the first covering 30A (covering 30), and the pair of electrodes 40 is different from that of the resistor A10 described above.

[0039] Unlike the resistor A10, the first insulator 11 is not provided with a pair of second convex portions 113. Further, the first layer 31 of the first covering 30A has a pair of fourth end faces 313 facing the first direction x. The dimension of the pair of fourth end faces 313 in the thickness direction z is larger than the corresponding dimension of the pair of fourth end faces 313 of the resistor A11. The pair of fourth end faces 313 are in contact with the side portions 42 of the pair of electrodes 40.

[0040] The pair of first convex portions 33 of the first covering 30A is composed of the second layer 32. The side portions 42 of the pair of electrodes 40 are in contact with the pair of first convex portions 33 formed of the second layer 32.

[0041] The configuration of the resistor A12 is obtained by making the depth of the plurality of grooves 881 greater than the depth of the plurality of grooves 881 formed during the manufacture of the resistor A11 in the step of forming the plurality of grooves 881 shown in FIG. 12.

[0042] (Third Modified Example) Based on FIG. 19, the resistor A13 according to the third modification example of the resistor A10 will be described. The resistor A13 is an example in which the configuration of the first layer 31 of the first coating body 30A (coating body 30) is different from that of the resistor A10 described above.

[0043] In the resistor A13, when viewed in the thickness direction z, the slit 311 of the first layer 31 is inclined with respect to the first direction x. When viewed in the thickness direction z, the slit 311 passes through the center C of the first coating body 30A and bends at the center C. As a result, with the center C as a boundary, the direction of inclination of the slit 311 with respect to the first direction x is reversed. Although illustration is omitted, also in the resistor A13, the side wall 312 of the slit 311 is concave toward the inside of the first layer 31.

[0044] (Fourth Modification Example) Based on FIG. 20, the resistor A14 according to the fourth modification example of the resistor A10 will be described. The resistor A14 is an example in which the configuration of the first layer 31 of the first coating body 30A (coating body 30) is different from that of the resistor A10 described above.

[0045] In the resistor A14, when viewed in the thickness direction z, the slit 311 of the first layer 31 has a first slit 311A and a plurality of second slits 311B. The first slit 311A extends in the first direction x. The plurality of second slits 311B are connected to both ends of the first slit 311A in the first direction x and extend in the second direction y. As a result, when viewed in the thickness direction z, the slit 311 has a crank shape. When viewed in the thickness direction z, the first slit 311A passes through the center C of the first coating body 30A. Although illustration is omitted, also in the resistor A14, the side wall 312 of the slit 311 is concave toward the inside of the first layer 31.

[0046] (Fifth Modification Example) Based on FIG. 21, the resistor A15 according to the fifth modification example of the resistor A10 will be described. The resistor A15 is an example in which the configuration of the first layer 31 of the first coating body 30A (coating body 30) is different from that of the resistor A10 described above.

[0047] In resistor A15, when viewed in the thickness direction z, the slit 311 of the first layer 31 extends in the second direction y. When viewed in the thickness direction z, the slit 311 passes through the center C of the first covering 30A. Although illustration is omitted, also in resistor A15, the side wall 312 of the slit 311 is concave toward the inside of the first layer 31.

[0048] Next, the operation and effect of resistor A10 will be described.

[0049] According to the configuration of resistor A10, it includes a first covering 30A (covering 30) laminated on the first insulator 11. The first covering 30A has a first layer 31 in contact with the first insulator 11. The first layer 31 has conductivity. Thus, when resistor A10 is in use, the heat generated from the resistor 20 flows to both the first insulator 11 and the second insulator 12. The heat flowing to the first insulator 11 flows to the first covering 30A. Since the first covering 30A has the first layer 31, the thermal conductivity of the first covering 30A is relatively greater than the thermal conductivities of the first insulator 11 and the second insulator 12. Therefore, the heat generated from the resistor 20 easily flows to the first covering 30A. The heat flowing to the first covering 30A is released to the outside of resistor A10. Therefore, according to resistor A10, it is possible to improve the heat dissipation performance.

[0050] The first layer 31 is provided with a slit 311 penetrating in the thickness direction z. The first layer 31 is divided into a plurality of regions by the slit 311. The coefficient of thermal expansion of the first layer 31 is relatively greater than the coefficients of thermal expansion of the first insulator 11, the second insulator 12, and the resistor 20. Therefore, due to the heat generated from the resistor 20, thermal stress is likely to concentrate between the first insulator 11 and the first covering 30A. When the concentration of thermal stress becomes excessive, warping in the thickness direction z occurs in resistor A10. Therefore, by providing the slit 311 in the first layer 31, the thermal stress between the first insulator 11 and the first covering 30A can be relaxed.

[0051] The first covering 30A has a pair of first convex portions 33 that project from a pair of first end faces 20A of the resistor body 20 in the first direction x. The pair of first convex portions 33 may be composed of both the first layer 31 and the second layer 32 as in the resistor A10 (see FIG. 9) and the resistor A11 (see FIG. 17), or may be composed of the second layer 32 as in the resistor A12 (see FIG. 18). In any case, when the side portions 42 of the pair of electrodes 40 contact the pair of first convex portions 33, the pair of electrodes 40 are electrically connected to the first layer 31. Therefore, by providing the slit 311 in the first layer 31, a short circuit between the pair of electrodes 40 can be prevented.

[0052] The first layer 31 is made of a material containing copper. Copper is a material with a relatively high thermal conductivity and a relatively small electrical resistivity. Thereby, the heat dissipation property of the resistor A10 can be further improved. Furthermore, variations in the resistance value of the resistor A10 caused by the pair of electrodes 40 contacting the first layer 31 can be suppressed.

[0053] The first insulator 11 contains a filler 112 having electrical insulation properties. The filler 112 can further improve the mechanical strength of the first insulator 11. Also, the filler 112 is made of a material containing ceramics with a relatively high thermal conductivity. Thereby, the thermal conductivity of the first insulator 11 becomes greater. Therefore, more heat generated from the resistor body 20 can be transmitted to the first covering 30A through the first insulator 11, so the heat dissipation property of the resistor A10 is further improved.

[0054] The first covering 30A has a second layer 32 that is laminated on the first layer 31 and has electrical insulation properties. Thereby, the first layer 31 can be protected and current leakage from the first layer 31 to the outside can be prevented. Also, a part of the second layer 32 is located in the slit 311 of the first layer 31. Thereby, since the contact area between the second layer 32 and the first layer 31 increases, the bonding strength of the second layer 32 to the first layer 31 can be enhanced.

[0055] The side wall 312 of the slit 311 of the first layer 31 is concave toward the inside of the first layer 31. Thereby, an anchoring effect on the second layer 32 is obtained in the slit 311, so that the bonding strength of the second layer 32 to the first layer 31 can be further increased.

[0056] The resistor 20 is provided with a plurality of resistance slits 21 penetrating in the thickness direction z. At least a part of the first insulator 11 and the second insulator 12 is located in the resistance slit 21. Thereby, since the contact area between at least one of the first insulator 11 and the second insulator 12 and the resistor 20 increases, the bonding strength of these to the resistor 20 can be increased.

[0057] The side wall 22 of the resistance slit 21 of the resistor 20 is concave toward the inside of the resistor 20. Thereby, an anchoring effect on at least one of the first insulator 11 and the second insulator 12 is obtained in the resistance slit 21, so that the bonding strength of these to the resistor 20 can be further increased.

[0058] Each of the pair of electrodes 40 is connected to the bottom 41 and has side portions 42 extending in the thickness direction z. The pair of side portions 42 are in contact with a pair of first end faces 20A of the resistor 20, a pair of second end faces 12C of the second insulator 12, and a pair of third end faces 11C of the first insulator 11. The pair of second end faces 12C and the pair of third end faces 11C are flush with the pair of first end faces 20A. Thereby, in the resistor 20, the portions where the pair of electrodes 40 are in contact are only the pair of first end faces 20A. The sizes of the pair of first end faces 20A are both equal. Thereby, variations in the resistance value of the resistor A10 can be suppressed.

[0059] 〔Second Embodiment〕 Based on FIGS. 22 and 23, the resistor A20 according to the second embodiment of the present disclosure will be described. In these figures, the same or similar elements as those of the resistor A10 described above are denoted by the same reference numerals, and redundant descriptions are omitted. Here, the cross-sectional position shown in FIG. 22 is the same as the cross-sectional position shown in FIG. 6.

[0060] In resistor A20, the structures of the first insulator 11, the second insulator 12, the coating 30, and the pair of electrodes 40 are different from those of resistor A10 described above.

[0061] As shown in FIG. 23, the second insulator 12 contains a filler 122 having electrical insulation properties. The material of the filler 122 is the same as the material of the filler 112 contained in the first insulator 11 of the resistor A10 described above. However, in resistor A20, the first insulator 11 does not contain the filler 112.

[0062] As shown in FIG. 22, the coating 30 is laminated on the second back surface 12B of the second insulator 12. As a result, resistor A20 has a configuration including the second coating 30B of the coating 30.

[0063] As shown in FIG. 22, the second coating 30B, like the first coating 30A, has a first layer 31 and a second layer 32. The first layer 31 is in contact with the second back surface 12B of the second insulator 12. The first layer 31 has conductivity. The first layer 31 is made of a material containing copper. The material of the first layer 31 is preferably a material having a relatively small electrical resistivity and a relatively large thermal conductivity. The second layer 32 is laminated on the first layer 31. The second layer 32 is a synthetic resin sheet having electrical insulation properties. As an example of the synthetic resin sheet, a sheet containing a glass epoxy resin can be mentioned.

[0064] As shown in FIG. 23, the first layer 31 is provided with a slit 311 penetrating in the thickness direction z. Due to the slit 311, the first layer 31 is divided into a plurality of regions. The shape of the slit 311 can be selected from any of the resistors A10 (see FIG. 2), resistor A13 (see FIG. 19), resistor A14 (see FIG. 20), and resistor A15 (see FIG. 21) described above. The side wall 312 of the slit 311 is concave toward the inside of the first layer 31.

[0065] As shown in FIG. 23, the second layer 32 is provided with an embedded portion 321. The embedded portion 321 protrudes in the thickness direction z from the surface of the second layer 32 in contact with the first layer 31. The embedded portion 321 is located in the slit 311 of the first layer 31. Thus, a part of the second layer 32 is configured to be located in the slit 311. In the resistor A20, the embedded portion 321 is in contact with the side wall 312 of the slit 311.

[0066] As shown in FIGS. 22 and 23, the first layer 31 has a pair of fourth end faces 313. The pair of fourth end faces 313 face the first direction x. The second layer 32 has a pair of fifth end faces 322. The pair of fifth end faces 322 face the first direction x. The pair of fourth end faces 313 and the pair of fifth end faces 322 are flush with a pair of first end faces 20A of the resistor body 20. In the resistor A20, the second coating 30B is not provided with a pair of first convex portions 33.

[0067] As shown in FIGS. 22 and 23, the bottoms 41 of the pair of electrodes 40 are in contact with the second layer 32 of the second coating 30B. As shown in FIG. 23, the side portions 42 of the pair of electrodes 40 are in contact with a pair of first end faces 20A of the resistor body 20, a pair of second end faces 12C of the second insulator 12, and a pair of third end faces 11C of the first insulator 11. Further, the pair of side portions 42 are in contact with a pair of fourth end faces 313 of the first layer 31 and a pair of fifth end faces 322 of the second layer 32. The pair of side portions 42 are in contact with a pair of second convex portions 113 of the first insulator 11.

[0068] Next, the operation and effect of the resistor A20 will be described.

[0069] According to the configuration of the resistor A20, it includes a second coating 30B (coating 30) laminated on the second insulator 12. The second coating 30B has a first layer 31 in contact with the second insulator 12. The first layer 31 has conductivity. Thereby, when the resistor A20 is used, the heat generated from the resistor 20 flows to both the first insulator 11 and the second insulator 12. The heat flowing to the second insulator 12 flows to the second coating 30B. Since the second coating 30B has the first layer 31, the thermal conductivity of the second coating 30B is relatively greater than the thermal conductivities of the first insulator 11 and the second insulator 12. Therefore, the heat generated from the resistor 20 easily flows to the second coating 30B. The heat flowing to the second coating 30B is released to the outside of the resistor A20. Therefore, the heat dissipation performance can also be improved by the resistor A20.

[0070] The second insulator 12 contains a filler 122 having electrical insulation properties. The filler 122 can further improve the mechanical strength of the second insulator 12. Further, the filler 112 is made of a material containing ceramics having a relatively high thermal conductivity. Thereby, the thermal conductivity of the second insulator 12 becomes greater. Therefore, since more heat generated from the resistor 20 can be transmitted to the second coating 30B through the second insulator 12, the heat dissipation performance of the resistor A20 is further improved.

[0071] The bottom portions 41 of the pair of electrodes 40 are in contact with the second layer 32 of the second coating 30B. Thereby, the heat generated from the resistor 20 and transmitted to the second coating 30B through the second insulator 12 can be quickly dissipated to the outside of the resistor A20 by the pair of electrodes 40.

[0072] 〔Third Embodiment〕 Based on FIGS. 24 and 25, the resistor A30 according to the third embodiment of the present disclosure will be described. In these figures, the same or similar elements as those of the aforementioned resistor A10 are denoted by the same reference numerals, and redundant descriptions are omitted. Here, the cross-sectional position shown in FIG. 24 is the same as the cross-sectional position shown in FIG. 6.

[0073] In resistor A30, the configuration of the second insulator 12, the coating 30, and the pair of electrodes 40 is different from that of resistor A10 described above.

[0074] As shown in FIG. 25, the second insulator 12 contains a filler 122 having electrical insulation properties. The material of the filler 122 is the same as the material of the filler 112 contained in the first insulator 11 of resistor A10 described above.

[0075] As shown in FIG. 24, the coating 30 is laminated on each of the first back surface 11B of the first insulator 11 and the second back surface 12B of the second insulator 12. As a result, resistor A30 has a configuration including both the first coating 30A and the second coating 30B out of 30. In resistor A30, the configuration of the first coating 30A is the same as the configuration of the first coating 30A of resistor A10 described above, and the configuration of the second coating 30B is the same as the configuration of the second coating 30B of resistor A20 described above. For this reason, the description of the first coating 30A and the second coating 30B will be omitted.

[0076] As shown in FIGS. 24 and 25, the bottom portions 41 of the pair of electrodes 40 are in contact with the second layer 32 of the second coating 30B. As shown in FIG. 25, the side portions 42 of the pair of electrodes 40 are in contact with the pair of first end faces 20A of the resistor body 20, the pair of second end faces 12C of the second insulator 12, and the pair of third end faces 11C of the first insulator 11. Further, the pair of side portions 42 are in contact with the pair of fourth end faces 313 of the first layer 31 and the pair of fifth end faces 322 of the second layer 32. The pair of side portions 42 are in contact with both the pair of first convex portions 33 of the first coating 30A and the pair of second convex portions 113 of the first insulator 11. Resistor A30 can also have the same configuration as resistor A11 (see FIG. 17) and resistor A12 (see FIG. 18) described above.

[0077] Next, the operation and effect of resistor A30 will be described.

[0078] According to the configuration of the resistor A30, it includes a first coating 30A (coating 30) laminated on the first insulator 11 and a second coating 30B (coating 30) laminated on the second insulator 12. The first coating 30A has a first layer 31 in contact with the first insulator 11. The second coating 30B has a first layer 31 in contact with the second insulator 12. The first layer 31 has conductivity. Thereby, when the resistor A30 is in use, the heat generated from the resistor 20 flows to the first coating 30A and the second coating 30B through both the first insulator 11 and the second insulator 12. Since the first coating 30A and the second coating 30B have the first layer 31, the thermal conductivity of the first coating 30A and the second coating 30B is relatively greater than the thermal conductivity of the first insulator 11 and the second insulator 12. For this reason, the heat generated from the resistor 20 easily flows to the first coating 30A and the second coating 30B. The heat that has flowed into the first coating 30A and the second coating 30B is released to the outside of the resistor A30. Therefore, the heat dissipation performance can also be improved by the resistor A30.

[0079] 〔Fourth Embodiment〕 Based on FIGS. 26 to 29, the resistor A40 according to the fourth embodiment of the present disclosure will be described. In these figures, the same or similar elements as those of the resistor A10 described above are denoted by the same reference numerals, and redundant descriptions are omitted. Here, for convenience of understanding, FIG. 26 shows the second layer 32 of the coating 30 being transparent.

[0080] In the resistor A40, the dimensions of each component and the configuration of the pair of electrodes 40 are different from those of the resistor A10 described above.

[0081] The dimensions of each of the first insulator 11, the resistor 20, the second insulator 12, the coating 30, and the pair of electrodes 40 that make up the resistor A40 in the first direction x and the second direction y are the same as those of each corresponding dimension of the resistor A10. However, as can be understood from FIGS. 26 to 28, the dimension of each of these elements in the thickness direction z that makes up the resistor A10 is smaller than each corresponding dimension of the resistor A10. The dimensions of the resistor A40 are closer to those of an actual product compared to the resistor A10. Further, the number of the plurality of resistor slits 21 of the resistor 20 is larger than the number of the plurality of resistor slits 21 of the resistor A10.

[0082] As shown in FIGS. 28 and 29, each side portion 42 of the pair of electrodes 40 is in contact with the second layer 32 of the first coating 30A (coating 30). As shown in FIG. 29, the dimension of each of the pair of first convex portions 33 of the first coating 30A in the first direction x is larger than each corresponding dimension of the resistor A10. Also, the dimension of each of the pair of second convex portions 113 of the first insulator 11 in the first direction x is larger than each corresponding dimension of the resistor A10.

[0083] The present disclosure is not limited to the above-described embodiments. The specific configuration of each part of the present disclosure can be freely designed in various ways.

[0084] The present disclosure includes the embodiments described in the following appendices.

[0085] Appendix 1. A resistor comprising: a first insulator having a main surface facing the thickness direction; a resistor disposed on the main surface; a second insulator covering the resistor; a pair of electrodes electrically connected to the resistor on both sides in a first direction orthogonal to the thickness direction; and a coating laminated on at least one of the first insulator and the second insulator, wherein the coating has a first layer that is conductive and in contact with at least one of the first insulator and the second insulator.

[0086] Supplementary Note 2. The first layer is provided with slits penetrating in the thickness direction. The resistor according to Supplementary Note 1, wherein the first layer is divided into a plurality of regions by the slits.

[0087] Supplementary Note 3. The resistor according to Supplementary Note 2, wherein the slits are inclined with respect to the first direction when viewed in the thickness direction.

[0088] Supplementary Note 4. The resistor according to Supplementary Note 2, wherein when viewed in the thickness direction, the slits include a first slit extending in the first direction and a plurality of second slits extending in a second direction orthogonal to the thickness direction and the first direction.

[0089] Supplementary Note 5. The resistor according to any one of Supplementary Notes 2 to 4, wherein the first layer is made of a material containing copper.

[0090] Supplementary Note 6. At least one of the first insulator and the second insulator contains a filler having electrical insulation properties. The resistor according to any one of Supplementary Notes 2 to 5, wherein the filler is made of a material containing ceramics.

[0091] Supplementary Note 7. The coating has a second layer laminated on the first layer and having electrical insulation properties. The resistor according to any one of Supplementary Notes 2 to 6, wherein a part of the second layer is located in the slits.

[0092] Supplementary Note 8. The resistor according to Supplementary Note 7, wherein the side walls of the slits are concave toward the inside of the first layer.

[0093] Supplementary Note 9. The resistor body is provided with resistor slits penetrating in the thickness direction. The resistor according to Supplementary Note 7 or 8, wherein at least a part of the first insulator and the second insulator is located in the resistor slits.

[0094] Supplementary Note 10. The resistor according to Supplementary Note 9, wherein the side walls of the resistor slits are concave toward the inside of the resistor body.

[0095] Supplementary Note 11. Each of the pair of electrodes has a bottom portion and a side portion. The bottom portion is located on the side opposite to the resistor with respect to the second insulator in the thickness direction, and overlaps the main surface when viewed in the thickness direction. The side portion is connected to the bottom portion of either one of the pair of electrodes and extends in the thickness direction. The resistor has a pair of first end faces facing the first direction, and the side portion of each of the pair of electrodes is in contact with either one of the pair of first end faces. The resistor according to any one of Supplementary Notes 7 to 10.

[0096] Supplementary Note 12. The second insulator has a pair of second end faces facing the first direction and flush with either one of the pair of first end faces. The side portion of each of the pair of electrodes is in contact with either one of the pair of second end faces. The resistor according to Supplementary Note 11.

[0097] Supplementary Note 13. The first insulator has a pair of third end faces facing the first direction and flush with either one of the pair of first end faces. The side portion of each of the pair of electrodes is in contact with either one of the pair of third end faces. The resistor according to Supplementary Note 12.

[0098] Supplementary Note 14. The covering includes a first covering laminated on the first insulator. The first covering has a pair of first convex portions that are separated from each other in the first direction and protrude from the pair of first end faces in the first direction. The side portion of each of the pair of electrodes is in contact with either one of the pair of first convex portions. The resistor according to any one of Supplementary Notes 11 to 13.

[0099] Supplementary Note 15. The pair of first convex portions is composed of the second layer of the first covering. The resistor according to Supplementary Note 14.

[0100] Supplementary Note 16. The first insulator has a pair of second convex portions that are separated from each other in the first direction and protrude from the pair of first end faces in the first direction. The side portions of each of the pair of electrodes are in contact with both any one of the pair of first convex portions and any one of the pair of second convex portions, the resistor according to appended note 14.

[0101] Appended note 17. The coating further includes a second coating laminated on the second insulator, The bottom portions of the pair of electrodes are in contact with the second layer of the second coating, the resistor according to any one of appended notes 14 to 16.

Claims

1. a first insulator having a first main surface and a first back surface facing in opposite directions in a thickness direction; A resistor disposed on the first main surface; A second insulator covering the resistor; A pair of electrodes that are electrically connected to the resistor on both sides in a first direction perpendicular to the thickness direction; a first coating body laminated on the first back surface, the first coating has a first layer that is conductive and in contact with the first back surface, The resistor has a first end surface facing one side in the first direction, the first insulator has a third end surface that faces the same side as the first end surface in the first direction and is flush with the first end surface; the first layer has a fourth end surface facing the same side as the first end surface in the first direction; Each of the pair of electrodes has a side portion including a portion extending in the thickness direction, the fourth end surface is spaced from the first end surface in the first direction toward a side on which the side portion of one of the pair of electrodes is located, with the first end surface being used as a reference; a resistor, in a cross section taken along the thickness direction and the first direction, the side portion of either of the pair of electrodes covers the entirety of each of the first end face, the third end face, and the fourth end face.

2. The first insulator has a second convex portion protruding from the first end face in the first direction, The resistor according to claim 1 , wherein the side portion of either of the pair of electrodes is in contact with the second protrusion.

3. The first layer is provided with a slit penetrating in the thickness direction, The resistor according to claim 1 , wherein the first layer is divided into a plurality of regions by the slits.

4. A resistor as described in claim 3, wherein when viewed in the thickness direction, the slit is inclined with respect to the first direction.

5. A resistor as described in claim 3, wherein, when viewed in the thickness direction, the slits have a first slit extending in the first direction and a plurality of second slits extending in a second direction perpendicular to the thickness direction and the first direction.

6. A resistor as described in any one of claims 3 to 5, wherein the first layer is made of a material containing copper.

7. At least one of the first insulator and the second insulator contains a filler having electrical insulation properties, 7. The resistor according to claim 3, wherein the filler is made of a material containing ceramics.

8. The first coating body has a second layer laminated on the first layer and having electrical insulation properties, 8. The resistor according to claim 3, wherein a portion of the second layer is located in the slit.

9. A resistor as described in claim 8, wherein the side walls of the slit are concave toward the inside of the first layer.

10. The resistor is provided with a resistance slit penetrating in the thickness direction, The resistor according to claim 8 or 9, wherein a portion of the second insulator is located in the resistive slit.

11. A resistor as described in claim 10, wherein the side walls of the resistor slit are concave toward the inside of the resistor body.

12. Each of the pair of electrodes is located on the opposite side of the resistor with respect to the second insulator in the thickness direction, and has a bottom connected to one of the sides of the pair of electrodes, The resistor according to claim 1 , wherein the bottom portion of each of the pair of electrodes overlaps the first main surface when viewed in the thickness direction.

13. The second insulator has a second end face facing the same side as the first end face in the first direction and being flush with the first end face; The resistor according to claim 12 , wherein the side portion of either of the pair of electrodes is in contact with the second end surface.

14. The resistor further comprises a second coating body located on the opposite side of the second insulator in the thickness direction and laminated on the second insulator; The resistor according to claim 12 or 13, wherein the bottom portion of each of the pair of electrodes is in contact with the second coating.

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