Resistors

Abstract

To provide a resistor capable of evenly suppressing an increase in temperature of a resistive element.SOLUTION: A resistor A30 includes a resistive element 10, an insulation plate, and a pair of electrodes 50. Each of the pair of electrodes 50 includes a bottom portion 51 positioned opposite to the insulation plate with respect to the resistive element 10 in a thickness direction. The resistor 10 includes a pair of first resistors 101 spaced apart from each other in the first direction x, a second resistor 102 located between the pair of first resistors 101, and a pair of connection portions 103 connected to the pair of first resistors 101 while being in contact with the pair of electrodes 50. When viewed in the thickness direction, each of the pair of first resistors 101 overlaps with one of the bottom portions 51 of the pair of electrodes 50. A maximum width w1max of a conduction path in each of the pair of first resistors 101 is narrower than a minimum width w2min of a conduction path in the second resistors 102.SELECTED DRAWING: Figure 23

Description

[Technical field]

[0001] The present disclosure relates primarily to resistors used for current sensing. [Background technology]

[0002] Conventionally, resistors having a resistive body made of a metal plate are known. Such resistors are mainly used for current detection. Patent Document 1 discloses an example of a resistor having a resistive body made of a metal plate. The resistor includes a resistive body, a pair of electrodes formed on both ends of a surface of the resistive body facing one side in the thickness direction of the resistive body, and a protective film covering the resistive body. A part of the protective film covering the surface of the resistive body is located between the pair of electrodes.

[0003] When a larger current is detected by the resistor, the heat generated from the resistor increases. If the temperature of the resistor increases due to this heat, the resistance value of the resistor may fluctuate. Therefore, in order to improve the heat dissipation of the resistor, a measure may be taken to increase the surface area of ​​each of the pair of electrodes. When taking such a measure, a configuration may be adopted in which a part of the pair of electrodes overlaps the protective film when viewed in the thickness direction of the resistor in order to suppress the increase in the size of the resistor. The pair of electrodes based on this configuration can be formed by forming a metal thin film on the protective film by a sputtering method and then performing electrolytic barrel plating.

[0004] However, when a resistor having the above configuration is used, there is a risk that the portions of the pair of electrodes in contact with the protective film may peel off due to the influence of thermal stress acting on the interface between each of the pair of electrodes and the protective film during use of the resistor. If such peeling occurs, the heat dissipation of the resistor decreases, causing fluctuations in the resistance value of the resistor. For this reason, measures are required to prevent the peeling of the pair of electrodes caused by thermal stress in the resistor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-225602 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a resistor capable of uniformly suppressing a temperature rise in the resistor element. [Means for solving the problem]

[0007] The resistor provided by the present disclosure includes a resistor having a first surface facing one side in a thickness direction, an insulating plate disposed on the first surface, and a pair of electrodes spaced apart from each other in a first direction perpendicular to the thickness direction and in contact with the resistor. Each of the pair of electrodes has a bottom portion located on the opposite side of the insulating plate with respect to the resistor in the thickness direction. The resistor includes a pair of first resistance parts spaced apart from each other in the first direction, a second resistance part located between the pair of first resistance parts, and a pair of connection parts in contact with the pair of electrodes and connected to the pair of first resistance parts. When viewed in the thickness direction, each of the pair of first resistance parts overlaps one of the bottom parts of each of the pair of electrodes. The maximum width of the conductive path of each of the pair of first resistance parts is smaller than the minimum width of the conductive path of the second resistance part.

[0008] The features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of a resistor according to the first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a plan view corresponding to FIG. 1 and seen through an insulating plate. [Diagram 3] FIG. 2 is a bottom view of the resistor shown in FIG. [Figure 4] FIG. 4 is a bottom view corresponding to FIG. 3 and showing a pair of electrodes in perspective. [Diagram 5] FIG. 4 is a bottom view corresponding to FIG. 3, showing a pair of electrodes and a pair of intermediate layers. [Figure 6] FIG. 2 is a right side view of the resistor shown in FIG. [Figure 7] FIG. 2 is a front view of the resistor shown in FIG. [Figure 8] FIG. 3 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is a partially enlarged view of FIG. 8. [Figure 10] FIG. 9 is a partially enlarged view of FIG. 8. [Figure 11] 2A to 2C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. [Figure 12] 2A to 2C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. [Figure 13] 2A to 2C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. [Figure 14] 2A to 2C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. [Figure 15] 2A to 2C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. [Figure 16] FIG. 11 is a bottom view of a resistor according to a second embodiment of the present disclosure, showing a pair of electrodes in perspective. [Figure 17] FIG. 17 is a cross-sectional view of the resistor shown in FIG. [Figure 18] FIG. 18 is a partially enlarged view of FIG. [Figure 19] 17A to 17C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 16. [Figure 20] 17A to 17C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 16. [Figure 21] 17A to 17C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 16. [Figure 22] FIG. 13 is a plan view of a resistor according to a third embodiment of the present disclosure. [Figure 23] FIG. 23 is a plan view corresponding to FIG. 22, seen through an insulating plate. [Figure 24] FIG. 23 is a bottom view of the resistor shown in FIG. 22. [Diagram 25]FIG. 25 is a bottom view corresponding to FIG. 24, showing a pair of electrodes in perspective. [Figure 26] FIG. 25 is a bottom view corresponding to FIG. 24, showing a pair of electrodes and a pair of intermediate layers. [Figure 27] FIG. 23 is a right side view of the resistor shown in FIG. 22. [Figure 28] FIG. 23 is a front view of the resistor shown in FIG. 22. [Figure 29] FIG. 29 is a cross-sectional view taken along line XXIX-XXIX in FIG. 23. [Diagram 30] FIG. 30 is a partially enlarged view of FIG. 29. [Diagram 31] FIG. 30 is a partially enlarged view of FIG. 29. [Diagram 32] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Diagram 33] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Diagram 34] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Diagram 35] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Diagram 36] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Figure 37] 23A to 23C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 22. [Figure 38] FIG. 13 is a plan view of a resistor according to a modified example of the third embodiment of the present disclosure, seen through an insulating plate. [Figure 39] 39 is a cross-sectional view taken along line XXXIX-XXXIX in FIG. 38. [Diagram 40] FIG. 13 is a plan view of a resistor according to a fourth embodiment of the present disclosure, seen through an insulating plate. [Diagram 41] FIG. 41 is a bottom view of the resistor shown in FIG. 40 , showing a pair of electrodes. [Diagram 42] FIG. 41 is a front view of the resistor shown in FIG. 40. [Diagram 43] FIG. 41 is a cross-sectional view taken along line XLIII-XLIII in FIG. 40. [Diagram 44] FIG. 44 is a partially enlarged view of FIG. 43. [Diagram 45] 41A to 41C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 40. [Figure 46] 41A to 41C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 40. [Figure 47] 41A to 41C are cross-sectional views illustrating a manufacturing process of the resistor shown in FIG. 40. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0011] [First embodiment] A resistor A10 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 10. The resistor A10 is intended as 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 resistive element 10, an insulating plate 20, a protective film 30, a pair of intermediate layers 40, and a pair of electrodes 50. Here, FIG. 2 shows the insulating plate 20 through for ease of understanding. FIG. 4 shows the pair of electrodes 50 through for ease of understanding. FIG. 5 shows the pair of intermediate layers 40 and the pair of electrodes 50 through for ease of understanding. In these figures, the pair of intermediate layers 40 and the pair of electrodes 50 through which they are seen are indicated by imaginary lines (two-dot chain lines).

[0012] In the explanation of the resistor A10 and resistors A20 to A40 described later, for convenience, the direction along the thickness of the resistor 10 is referred to as the "thickness direction z." A direction perpendicular to the thickness direction z is referred to as the "first direction x." A direction perpendicular to both the thickness direction z and the first direction x is referred to as the "second direction y." As shown in FIG. 1, the resistor A10 is rectangular when viewed in the thickness direction z. The first direction x corresponds to the longitudinal direction of the resistor A10. The second direction y corresponds to the lateral direction of the resistor A10.

[0013] The resistor 10 constitutes the functional core of the resistor A10. The resistor 10 is a metal plate. The material of the metal plate is, for example, a copper (Cu)-manganese (Mn)-nickel (Ni) alloy (Manganin: registered trademark) or a copper-manganese-tin (Sn) alloy (Zeranin: registered trademark). The thickness of the resistor 10 is 50 μm or more and 150 μm or less.

[0014] As shown in FIG. 8, the resistor 10 has a first surface 10A, a second surface 10B, and a pair of first end surfaces 10C. The first surface 10A faces one side in the thickness direction z. The second surface 10B faces the opposite side to the first surface 10A. Therefore, the first surface 10A and the second surface 10B face opposite sides to each other in the thickness direction z. The pair of first end surfaces 10C are spaced apart from each other in the first direction x. Each of the pair of first end surfaces 10C is connected to both the first surface 10A and the second surface 10B.

[0015] As shown in FIG. 5, the resistor 10 has a plurality of slits 11 and a plurality of grooves 12. The plurality of slits 11 and the plurality of grooves 12 are provided to adjust the resistance value of the resistor 10 to a predetermined value. As shown in FIG. 8, each of the plurality of slits 11 penetrates the resistor 10 from the first surface 10A to the second surface 10B. As shown in FIG. 2, each of the plurality of slits 11 extends in the second direction y. Due to the plurality of slits 11, both ends of the resistor 10 in the second direction y are partially open. As shown in FIG. 9, each of the plurality of slits 11 has a pair of side walls 111. The pair of side walls 111 are spaced apart from each other in the first direction x. Each of the pair of side walls 111 is connected to both the first surface 10A and the second surface 10B. Each of the pair of side walls 111 includes a portion that is concave toward the first direction x. As shown in Figures 5 and 10, the multiple grooves 12 are recessed from the second surface 10B and extend in a predetermined direction. In the example of resistor A10, each of the multiple grooves 12 extends in the second direction y. As shown in Figure 10, the maximum width bmax of each of the multiple grooves 12 is smaller than the minimum width Bmin of each of the multiple slits 11 (see Figure 9). The number of slits 11 can be freely set depending on the resistance value required for the resistor 10.

[0016] As shown in FIG. 8, the insulating plate 20 is disposed on the first surface 10A of the resistor 10. The insulating plate 20 is made of a material containing synthetic resin. In the example shown in the resistor A10, the insulating plate 20 is a synthetic resin sheet containing epoxy resin. The insulating plate 20 has a pair of second end faces 20A. The pair of second end faces 20A face opposite each other in the first direction x and are spaced apart from each other in the first direction x. Each of the pair of second end faces 20A is flush with one of the pair of first end faces 10C. A part of the insulating plate 20 enters the multiple slits 11 of the resistor 10 in the thickness direction z.

[0017] As shown in FIG. 8, the protective film 30 is disposed on the second surface 10B of the resistor 10. The protective film 30 is made of a material that has electrical insulation and contains a synthetic resin. In the example shown in the resistor A10, the protective film 30 is made of a material that contains an epoxy resin. As shown in FIG. 9 and FIG. 10, the protective film 30 contains a filler 31. The filler 31 is made of a material that contains ceramics. The ceramics are preferably ones having a relatively high thermal conductivity, such as alumina (Al2O3) or boron nitride (BN). The protective film 30 is in contact with both the second surface 10B and the surface of the insulating plate 20 facing the same side as the second surface 10B. As shown in FIG. 5, the protective film 30 is located inward in the first direction x from the pair of first end surfaces 10C of the resistor 10 as viewed in the thickness direction z. As shown in FIG. 10, the protective film 30 is engaged with a plurality of grooves 12 of the resistor 10.

[0018] As shown in FIG. 8, the pair of intermediate layers 40 are located on the opposite side of the insulating plate 20 with respect to the resistor 10 in the thickness direction z. The pair of intermediate layers 40 are spaced apart from each other in the first direction x. The pair of intermediate layers 40 are made of a material that is conductive and contains a synthetic resin. The pair of intermediate layers 40 are electrically connected to the resistor 10. The pair of intermediate layers 40 contain metal particles. The metal particles contain silver (Ag). In the example shown by the resistor A10, the synthetic resin contained in the pair of intermediate layers 40 is an epoxy resin. The electrical resistivity of the pair of intermediate layers 40 is about 10 times that of the resistor 10. Therefore, the electrical resistivity of the pair of intermediate layers 40 is greater than that of the resistor 10.

[0019] As shown in FIG. 4 and FIG. 8, each of the pair of intermediate layers 40 has a covering portion 41 and an extending portion 42. The covering portion 41 is located on the opposite side of the protective film 30 from the resistor 10 in the thickness direction z. The covering portion 41 covers a part of the protective film 30. The extending portion 42 extends from one of the covering portions 41 of the pair of intermediate layers 40 to one of the pair of first end faces 10C of the resistor 10. The extending portion 42 is in contact with both the second face 10B of the resistor 10 and the face of the insulating plate 20 facing the same side as the second face 10B. As a result, the pair of intermediate layers 40 are electrically connected to the resistor 10. As shown in FIG. 4 and FIG. 7, a recess 421 is formed in each of the extending portions 42 of the pair of intermediate layers 40. The recess 421 is recessed from one of the pair of first end faces 10C toward the first direction x. When viewed in the thickness direction z, the recess 421 is rectangular. 4, 5 and 8, the second surface 10B of the resistor 10 includes a first region 13 located between one of the pair of first end faces 10C and the protective film 30 when viewed in the thickness direction z. The first region 13 is exposed from the pair of intermediate layers 40. The first region 13 appears from the recess 421.

[0020] The pair of electrodes 50 are disposed spaced apart from each other in the first direction x, as shown in Figs. 1 to 3, 6 and 8. Each of the pair of electrodes 50 is in contact with the resistor 10. This allows the pair of electrodes 50 to be electrically connected to the resistor 10. Each of the pair of electrodes 50 is made up of a plurality of metal layers. In the example shown in resistor A10, the plurality of metal layers are formed by stacking a copper layer, a nickel layer and a tin layer in this order from the side closest to the resistor 10.

[0021] 3 and 6 to 8, each of the pair of electrodes 50 has a bottom 51. The bottom 51 is located on the opposite side of the resistor 10 from the insulating plate 20 in the thickness direction z. The bottom 51 overlaps a part of the protective film 30 when viewed in the thickness direction z.

[0022] 6 and 8, each of the covering portions 41 of the pair of intermediate layers 40 is located between the protective film 30 and either of the bottom portions 51 of the pair of electrodes 50. In the resistor A10, each of the covering portions 41 of the pair of intermediate layers 40 is in contact with both the protective film 30 and either of the bottom portions 51 of the pair of electrodes 50.

[0023] 6 and 8, each of the extensions 42 of the pair of intermediate layers 40 is located between the resistor 10 and one of the bottoms 51 of the pair of electrodes 50. Each of the bottoms 51 of the pair of electrodes 50 is in contact with one of the extensions 42 of the pair of intermediate layers 40. In addition, each of the bottoms 51 of the pair of electrodes 50 is in contact with the first region 13 of the second surface 10B of the resistor 10 and the protective film 30.

[0024] 1 to 3 and 6 to 8, each of the pair of electrodes 50 has a side portion 52. The side portion 52 is connected to one of the bottom portions 51 of the pair of electrodes 50 and stands up in the thickness direction z. Each of the side portions 52 of the pair of electrodes 50 contacts one of the pair of first end faces 10C of the resistor 10. In addition, each of the side portions 52 of the pair of electrodes 50 contacts one of the pair of second end faces 20A of the insulating plate 20.

[0025] Next, an example of a method for manufacturing the resistor A10 will be described with reference to Figures 11 to 15. Here, the cross-sectional positions shown in Figures 11 to 15 are the same as the cross-sectional position shown in Figure 8.

[0026] First, as shown in FIG. 11, a base material 82 is thermocompression-bonded to a resistor 81 having a first surface 81A and a second surface 81B facing opposite sides in the thickness direction z. The resistor 81 is a resistor A10 having a plurality of resistors 10 arranged in a first direction x and a second direction y. The first surface 81A corresponds to the first surface 10A of the resistor 10. The second surface 81B corresponds to the second surface 10B of the resistor 10. The base material 82 is a resistor A10 having a plurality of insulating plates 20 arranged in a first direction x and a second direction y. First, a plurality of slits 811 penetrating from the first surface 10A to the second surface 81B are formed in the resistor 81. The plurality of slits 811 correspond to the plurality of slits 11 of the resistor A10. The plurality of slits 811 are formed by wet etching. Next, the base material 82 is thermocompression-bonded to the first surface 81A by lamination pressing. When the base material 82 is pressure-bonded to the first surface 81A, a portion of the base material 82 enters the multiple slits 811 in the thickness direction z. Finally, with a probe for measuring the resistance value of the resistor 81 in contact with the second surface 10B, multiple grooves 812 recessed from the second surface 10B are formed in the resistor 81. The multiple grooves 812 correspond to the multiple grooves 12 of the resistor A10. The multiple grooves 12 are formed, for example, by laser irradiation. When the resistance value of the resistor 81 reaches a predetermined value, the formation of the multiple grooves 812 is completed.

[0027] 12, a protective film 30 is formed to cover each of the second surface 81B of the resistor 81 and a part of the surface of the base material 82 facing the same side as the second surface 81B. The protective film 30 is formed by applying a material containing an epoxy resin to the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B by screen printing, and then thermally curing the material.

[0028] 13, a pair of intermediate layers 40 are formed to cover a portion of each of the second surface 81B of the resistor 81, the surface of the base material 82 facing the same side as the second surface 81B, and the protective film 30. The pair of intermediate layers 40 are formed by applying a material containing silver particles and epoxy resin to the second surface 81B, the surface of the base material 82 facing the same side as the second surface 81B, and the protective film 30 by screen printing, and then thermally curing the material.

[0029] 14, the resistor 81 and the substrate 82 are cut along cutting lines CL with a dicing blade to separate them into pieces including the protective film 30 and the pair of intermediate layers 40. The pieces become the components of the resistor A10 excluding the pair of electrodes 50. That is, the resistor 81 separated into pieces becomes the resistor 10 of the resistor A10. In addition, the substrate 82 separated into pieces becomes the insulating plate 20 of the resistor A10. A pair of first end faces 10C of the resistor 10 and a pair of second end faces 20A of the insulating plate 20 are the cut surfaces of the resistor 81 and the substrate 82 formed in this process.

[0030] Finally, as shown in FIG. 15, a pair of electrodes 50 in contact with the resistor 10 are formed. The pair of electrodes 50 are formed by electrolytic barrel plating of a copper layer, a nickel layer, and a tin layer in this order. Each of the pair of intermediate layers 40 is covered by one of the bottoms 51 of the pair of electrodes 50. Each of the bottoms 51 of the pair of electrodes 50 contacts the first region 13 of the second surface 10B of the resistor 10 and the protective film 30. In addition, each of the pair of first end faces 10C of the resistor 10 and each part of the pair of second end faces 20A of the insulating plate 20 are covered by one of the side parts 52 of the pair of electrodes 50. Next, the pair of electrodes 50 is heat-treated under conditions of a temperature of 170° C. and 2 hours. This improves the bonding between each of the bottoms 51 of the pair of electrodes 50 and the resistor 10. Through the above steps, the resistor A10 is manufactured.

[0031] Next, the function and effect of the resistor A10 will be described.

[0032] In the resistor A10, the bottoms 51 of the pair of electrodes 50 overlap a part of the protective film 30 when viewed in the thickness direction z. The resistor A10 includes a pair of intermediate layers 40 that have a covering portion 41 that covers a part of the protective film 30 and are spaced apart from each other in the first direction x. The pair of intermediate layers 40 are made of a material that is conductive and contains a synthetic resin. Each of the covering portions 41 of the pair of intermediate layers 40 is located between the protective film 30 and one of the bottoms 51 of the pair of electrodes 50. As described in the process shown in FIG. 15, the pair of electrodes 50 are formed by electrolytic barrel plating, so that the bonding between each of the bottoms 51 of the pair of electrodes 50 and one of the covering portions 41 of the pair of intermediate layers 40 is good. In addition, when the resistor A10 is used, the thermal stress acting on the interface between each of the bottoms 51 of the pair of electrodes 50 and one of the covering portions 41 of the pair of intermediate layers 40 is alleviated by the covering portion 41. This reduces the thermal stress transmitted to the interface between each of the covering portions 41 of the pair of intermediate layers 40 and the protective film 30. This prevents the covering portions 41 of the pair of intermediate layers 40 from peeling off from the protective film 30 due to the influence of the thermal stress. Therefore, according to the resistor A10, it is possible to prevent the portions (bottoms 51) of the pair of electrodes 50 overlapping the protective film 30 from peeling off when viewed in the thickness direction z.

[0033] The protective film 30 is made of a material containing synthetic resin. As a result, the protective film 30 and the pair of intermediate layers 40 are configured to contain the same type of material, and therefore the bonding strength between the protective film 30 and the covering portions 41 of the pair of intermediate layers 40 can be improved.

[0034] The pair of intermediate layers 40 contain metal particles. This allows the pair of intermediate layers 40 to have conductive properties even if they are made of a material containing synthetic resin. In addition, the metal particles contain silver. As described in the process shown in FIG. 15, the pair of electrodes 50 formed by electrolytic barrel plating are heat-treated under predetermined conditions. Silver has properties that make it relatively resistant to thermal oxidation. Therefore, it is possible to improve the bonding between each of the bottoms 51 of the pair of electrodes 50 and one of the pair of intermediate layers 40.

[0035] The electrical resistivity of the pair of intermediate layers 40 is greater than the electrical resistivity of the resistor 10. As a result, when the resistor A10 is in use, the current flowing through the resistor 10 is less likely to flow through the pair of intermediate layers 40. Therefore, fluctuations in the resistance value of the resistor A10 due to the influence of the pair of intermediate layers 40 can be suppressed.

[0036] The protective film 30 contains filler 31 made of a material containing ceramics. This can increase the mechanical strength of the protective film 30. Furthermore, by selecting a ceramic material with a relatively high thermal conductivity, such as alumina or boron nitride, as the ceramic, the thermal conductivity of the protective film 30 can be increased. This can further improve the heat dissipation of the resistor A10.

[0037] The insulating plate 20 is made of a material containing a synthetic resin. As a result, in the process shown in FIG. 11, the base material 82 can be thermocompression bonded to the first surface 81A of the resistor 81 by lamination pressing. The resistor 10 has a plurality of slits 11 penetrating from the first surface 10A to the second surface 10B. A part of the insulating plate 20 enters the plurality of slits 11 in the thickness direction z. This generates an anchor effect of the insulating plate 20 with respect to the resistor 10, thereby improving the bonding between the resistor 10 and the insulating plate 20. Furthermore, each of the plurality of slits 11 has a pair of side walls 111 spaced apart in the first direction x. Each of the pair of side walls 111 has a portion that is concave toward the first direction x. This enhances the anchor effect of the insulating plate 20 with respect to the resistor 10, thereby further improving the bonding between the resistor 10 and the insulating plate 20.

[0038] The resistor 10 has a plurality of grooves 12 recessed from the second surface 10B and extending in a predetermined direction. The protective film 30 meshes with the plurality of grooves 12. This creates an anchoring effect in the protective film 30 with respect to the resistor 10, thereby improving the bond between the resistor 10 and the protective film 30.

[0039] The insulating plate 20 has a pair of second end faces 20A that face opposite each other in the first direction x and are spaced apart from each other in the first direction x. Each of the side portions 52 of the pair of electrodes 50 contacts one of the pair of second end faces 20A. This allows the dimension of each of the side portions 52 of the pair of electrodes 50 in the thickness direction z to be longer. When the resistor A10 is mounted on a wiring board, a solder fillet is formed on each of the side portions 52 of the pair of electrodes 50. Therefore, with this configuration, the volume of the solder fillet is further enlarged, and the mountability of the resistor A10 on the wiring board can be further improved.

[0040] The protective film 30 is located inward in the first direction x from the pair of first end faces 10C of the resistor 10 as viewed in the thickness direction z. Each of the bottoms 51 of the pair of electrodes 50 contacts the first region 13 of the second surface 10B of the resistor 10 located between one of the pair of first end faces 10C and the protective film 30 as viewed in the thickness direction z. This makes it easier for the current flowing through the resistor 10 to flow from the first region 13 to the bottoms 51 of the pair of electrodes 50 when the resistor A10 is used. This shortens the length of the current path in the resistor A10, thereby suppressing fluctuations in the resistance value of the resistor A10 due to the influence of the pair of electrodes 50.

[0041] Each of the extending portions 42 of the pair of intermediate layers 40 has a recess 421 recessed in the first direction x from one of the pair of first end faces 10C of the resistor 10. The first region 13 of the second surface 10B of the resistor 10 is exposed from the recess 421. Each of the bottom portions 51 of the pair of electrodes 50 contacts both the first region 13 and one of the extending portions 42 of the pair of intermediate layers 40. This makes it possible to increase the contact area between each of the pair of intermediate layers 40 and one of the bottom portions 51 of the pair of electrodes 50 while suppressing fluctuations in the resistance value of the resistor A10.

[0042] Second Embodiment A resistor A20 according to a second embodiment of the present disclosure will be described with reference to Figs. 16 to 18. In these figures, elements that are the same as or similar to those of the resistor A10 described above are given the same reference numerals, and duplicated descriptions will be omitted. Here, Fig. 16 shows a pair of electrodes 50 in a see-through manner for ease of understanding. In Fig. 16, the see-through pair of electrodes 50 is shown by imaginary lines. The cross-sectional position shown in Fig. 17 is the same as the cross-sectional position shown in Fig. 8.

[0043] In the resistor A20, the configurations of the protective film 30 and the pair of intermediate layers 40 are different from those in the resistor A10 described above.

[0044] As shown in FIG. 16 and FIG. 17, each of the pair of intermediate layers 40 includes a first layer 40A and a second layer 40B. The first layer 40A has an extension 42, and is in contact with both the second surface 10B of the resistor 10 and the surface of the insulating plate 20 facing the same side as the second surface 10B. The dimension of the first layer 40A in the thickness direction z is approximately uniform throughout. The second layer 40B has a covering portion 41. The second layer 40B is connected to one of the first layers 40A of the pair of intermediate layers 40. The second layer 40B is configured to cover a part of the first layer 40A.

[0045] 18, each of the first layers 40A of the pair of intermediate layers 40 has an intermediate portion 43 extending from the extending portion 42 toward the protective film 30. The intermediate portion 43 includes a portion located between the resistor 10 and the protective film 30. As a result, each of both ends of the protective film 30 in the first direction x is configured to cover one of the first layers 40A of the pair of intermediate layers 40. In the resistor A20, the intermediate portion 43 is in contact with both the resistor 10 and the protective film 30.

[0046] Next, an example of a method for manufacturing the resistor A20 will be described with reference to Figures 11, 14, 15, and 19 to 21. Here, the cross-sectional positions shown in Figures 19 to 21 are the same as the cross-sectional position shown in Figure 17.

[0047] 11, a base material 82 is thermocompression bonded to a resistor 81 having a first surface 81A and a second surface 81B facing opposite sides in a thickness direction z. This step is the same as the step in the manufacturing method of the resistor A10, and therefore a description thereof will be omitted here.

[0048] 19, first layers 40A of a pair of intermediate layers 40 are formed to cover a portion of each of the second surface 81B of the resistor 81 and the surface of the base material 82 facing the same side as the second surface 81B. The first layers 40A of the pair of intermediate layers 40 are formed by applying a material containing silver particles and epoxy resin by screen printing to both the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B. At this time, the material is applied while being spaced apart from each other in the first direction x. The material is then thermally cured to form the first layers 40A of the pair of intermediate layers 40.

[0049] 20, a protective film 30 is formed to cover the second surface 81B of the resistor 81 and a portion of the surface of the base material 82 facing the same side as the second surface 81B. First, a material containing an epoxy resin is applied by screen printing to the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B. At this time, each of both ends of the material in the first direction x is made to cover one of the first layers 40A of the pair of intermediate layers 40. Thereafter, the material is thermally cured to form the protective film 30.

[0050] Next, as shown in FIG. 21, the second layer 40B of the pair of intermediate layers 40 is formed to cover a part of the protective film 30. First, a material containing silver particles and an epoxy resin is applied to the protective film 30 by screen printing. At this time, the material is applied while being spaced apart from each other in the first direction x. In addition, each part of the material that is spaced apart from each other is made to cover a part of one of the first layers 40A of the pair of intermediate layers 40. Thereafter, the material is thermally cured to form the second layer 40B of the pair of intermediate layers 40.

[0051] 14, the resistor 81 and the substrate 82 are cut along cutting lines CL with a dicing blade to separate them into individual pieces including the protective film 30 and a pair of intermediate layers 40 (first layer 40A and second layer 40B). This step is the same as the step in the manufacturing method of the resistor A10, and therefore a description thereof will be omitted here.

[0052] Finally, a pair of electrodes 50 in contact with the resistor 10 is formed as shown in Fig. 15. This step is the same as the step in the manufacturing method of the resistor A10, so a description thereof will be omitted here. Through the above steps, the resistor A20 is manufactured.

[0053] Next, the function and effect of the resistor A20 will be described.

[0054] In the resistor A20, the bottoms 51 of the pair of electrodes 50 overlap a part of the protective film 30 when viewed in the thickness direction z. The resistor A20 includes a pair of intermediate layers 40 that have a covering portion 41 that covers a part of the protective film 30 and are spaced apart from each other in the first direction x. The pair of intermediate layers 40 are made of a material that is conductive and contains a synthetic resin. Each of the covering portions 41 of the pair of intermediate layers 40 is located between the protective film 30 and one of the bottoms 51 of the pair of electrodes 50. Therefore, the resistor A20 can also prevent the portions (bottoms 51) of the pair of electrodes 50 that overlap the protective film 30 from peeling off when viewed in the thickness direction z.

[0055] In the resistor A20, each of the pair of intermediate layers 40 includes a first layer 40A and a second layer 40B. The first layer 40A has an extension 42. The second layer 40B has a coating 41 and is connected to one of the first layers 40A of the pair of intermediate layers 40. This allows the dimension of each of the first layers 40A of the pair of intermediate layers 40 in the thickness direction z to be approximately uniform throughout. In the resistor A20, the first layer 40A of the pair of intermediate layers 40 is in contact with the second surface 10B of the resistor 10. Therefore, if the dimension of each of the first layers 40A of the pair of intermediate layers 40 in the thickness direction z is approximately uniform throughout, the fluctuation in the resistance value of the resistor A20 due to the influence of the pair of intermediate layers 40 can be further suppressed than in the case of the resistor A10.

[0056] Each of the first layers 40A of the pair of intermediate layers 40 has an intermediate portion 43 extending from the extending portion 42 toward the protective film 30. The intermediate portion 43 includes a portion located between the resistor 10 and the protective film 30. This increases the contact area of ​​the pair of intermediate layers 40 with the protective film 30. Therefore, the bond between the protective film 30 and the pair of intermediate layers 40 can be further improved compared to the case of the resistor A10.

[0057] Third Embodiment A resistor A30 according to a third embodiment of the present disclosure will be described with reference to Figs. 22 to 31. In these figures, elements that are the same as or similar to those of the resistor A10 described above are given the same reference numerals, and duplicated explanations will be omitted. Here, Fig. 23 is a perspective view of the insulating plate 20 for ease of understanding. Fig. 25 is a perspective view of the pair of electrodes 50 for ease of understanding. Fig. 26 is a perspective view of the pair of intermediate layers 40 and the pair of electrodes 50 for ease of understanding. In these figures, the perspective view of the pair of intermediate layers 40 and the pair of electrodes 50 is shown by imaginary lines.

[0058] 29, in the resistor A30, the resistor element 10 has a pair of side surfaces 10D in addition to the first surface 10A, the second surface 10B, and the pair of first end surfaces 10C. The pair of side surfaces 10D are spaced apart from each other in the second direction y. Each of the pair of side surfaces 10D is connected to both the first surface 10A and the second surface 10B.

[0059] As shown in FIG. 23, FIG. 26, and FIG. 29, in the resistor A30, the resistor 10 includes a pair of first resistor portions 101, a second resistor portion 102, and a pair of connecting portions 103. The pair of first resistor portions 101 are spaced apart from each other in the first direction x. The second resistor portion 102 is located between the pair of first resistor portions 101. Both ends of the second resistor portion 102 in the first direction x are connected to the pair of first resistor portions 101. The pair of connecting portions 103 are spaced apart from each other in the first direction x. The pair of connecting portions 103 are connected to the pair of first resistor portions 101. The pair of connecting portions 103 are located at the outermost positions in the first direction x in the resistor 10. Each of the pair of connecting portions 103 includes one of the pair of first end faces 10C.

[0060] 23, the maximum width w1max of the conductive path CP of each of the pair of first resistor portions 101 is smaller than the minimum width w2min of the conductive path CP of the second resistor portion 102. Here, the conductive path CP refers to the path of a current flowing through the resistor 10 when a predetermined potential difference is applied to the pair of electrodes 50. The width of the conductive path CP refers to the dimension of the resistor 10 in a direction perpendicular to the conductive path CP when viewed in the thickness direction z.

[0061] As shown in FIG. 23 and FIG. 26, each of the pair of side surfaces 10D is partially opened by the plurality of slits 11. The plurality of slits 11 are formed in a pair of first resistor parts 101. The second resistor part 102 is located next to the slit 11 located farthest from one of the pair of electrodes 50 in the first direction x among the plurality of slits 11. In addition, one of the pair of connection parts 103 is located next to the slit 11 located closest to one of the pair of electrodes 50 in the first direction x among the plurality of slits 11. The shape of the resistor 10 in which the plurality of slits 11 are formed is point symmetrical as viewed in the thickness direction z. In this case, point symmetry refers to a relationship in which one divided region and the other divided region are point symmetrical with respect to the center C when the resistor 10 is divided into two by a boundary B that passes through the center C of the resistor 10 shown in FIG. 23 and extends in the second direction y.

[0062] 26, the plurality of grooves 12 are formed in the second resistor portion 102. The plurality of grooves 12 may be formed in the pair of first resistor portions 101 in addition to the second resistor portion 102.

[0063] 23, 25, and 28, each of the pair of connecting portions 103 has a pair of protrusions 14. The pair of protrusions 14 are spaced apart from each other in the second direction y. Each of the pair of protrusions 14 protrudes from one of the pair of side surfaces 10D in the second direction y. Each of the pair of protrusions 14 is connected to one of the pair of first end faces 10C.

[0064] As shown in FIGS. 22 and 28, a first surface 10A of resistor 10 and a pair of side surfaces 10D of resistor 10 are covered with insulating plate 20. As shown in FIG.

[0065] In the resistor A30, the pair of intermediate layers 40 are made of a metal thin film, for example, a nickel-chromium (Cr) alloy.

[0066] As shown in FIG. 25, in resistor A30, the first region 13 is located between one of a pair of first end faces 10C and one of the extension portions 42 of a pair of intermediate layers 40 that is closest to the first end face 10C when viewed in the thickness direction z.

[0067] 23 and 29, each of the pair of electrodes 50 is in contact with one of the pair of connection portions 103 of the resistor 10. As a result, the pair of electrodes 50 is electrically connected to the resistor 10.

[0068] 23 and 29, each of the pair of first resistive portions 101 of the resistor 10 overlaps one of the bottom portions 51 of the pair of electrodes 50 when viewed in the thickness direction z. Each of the side portions 52 of the pair of electrodes 50 contacts one of the pair of first end faces 10C of the resistor 10.

[0069] Next, an example of a method for manufacturing the resistor A30 will be described with reference to Figures 32 to 37. Here, the cross-sectional positions shown in Figures 32 to 36 are the same as the cross-sectional position shown in Figure 29.

[0070] First, as shown in FIG. 32, a substrate 82 is thermocompression-bonded to a resistor 81 having a first surface 81A and a second surface 81B facing opposite each other in the thickness direction z. First, a plurality of slits 811 penetrating from the first surface 10A to the second surface 81B are formed in the resistor 81. The plurality of slits 811 correspond to the plurality of slits 11 of the resistor A30. The plurality of slits 811 are formed by wet etching. Next, the substrate 82 is thermocompression-bonded to the first surface 81A by lamination pressing. When the substrate 82 is compressed to the first surface 81A, a part of the substrate 82 enters the plurality of slits 811 in the thickness direction z. Finally, a plurality of grooves 812 recessed from the second surface 10B are formed in the resistor 81 with a probe for measuring the resistance value of the resistor 81 in contact with the second surface 10B. The plurality of grooves 812 correspond to the plurality of grooves 12 of the resistor A30. The grooves 12 are formed by, for example, laser irradiation. When the resistance value of the resistor 81 reaches a predetermined value, the formation of the grooves 812 is completed.

[0071] 33, a protective film 30 is formed to cover each of the second surface 81B of the resistor 81 and a part of the surface of the base material 82 facing the same side as the second surface 81B. The protective film 30 is formed by applying a material containing an epoxy resin to the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B by screen printing, and then thermally curing the material.

[0072] Next, as shown in FIG. 34, a metal thin film 83 is formed to cover the second surface 81B of the resistor 81, the surface of the base material 82 facing the same side as the second surface 81B, and the entire protective film 30. To form the metal thin film 83, first, a mask layer 89 is formed to cover each of the second surface 81B of the resistor 81, the surface of the base material 82 facing the same side as the second surface 81B, and a portion of the protective film 30. The mask layer 89 is formed by screen printing. After the mask layer 89 is formed, the metal thin film 83 is formed. The metal thin film 83 is made of a nickel-chromium alloy. The metal thin film 83 is formed by a sputtering method. In this process, the mask layer 89 is covered with the metal thin film 83.

[0073] 35, the mask layer 89 and a portion of the thin metal film 83 covering the mask layer 89 are removed (lifted off). This process forms a pair of intermediate layers 40 that cover the second surface 81B of the resistor 81, the surface of the base material 82 facing the same side as the second surface 81B, and a portion of the protective film 30. That is, the pair of intermediate layers 40 are formed from the thin metal film 83 remaining on the protective film 30, etc.

[0074] 36, the resistor 81 and the substrate 82 are cut along cutting lines CL with a dicing blade to separate them into pieces including the protective film 30 and a pair of intermediate layers 40. The pieces become the components of the resistor A30 excluding the pair of electrodes 50. That is, the resistor 81 separated into pieces becomes the resistor 10 of the resistor A30. In addition, the substrate 82 separated into pieces becomes the insulating plate 20 of the resistor A30. A pair of first end faces 10C of the resistor 10 and a pair of second end faces 20A of the insulating plate 20 are cut surfaces of the resistor 81 and the substrate 82 formed in this process.

[0075] Finally, as shown in FIG. 37, a pair of electrodes 50 in contact with the resistor 10 are formed. The pair of electrodes 50 are formed by electrolytic barrel plating of a copper layer, a nickel layer, and a tin layer in this order. Each of the pair of intermediate layers 40 is covered by one of the bottoms 51 of the pair of electrodes 50. Each of the bottoms 51 of the pair of electrodes 50 contacts the first region 13 of the second surface 10B of the resistor 10 and the protective film 30. In addition, each of the pair of first end faces 10C of the resistor 10 and each part of the pair of second end faces 20A of the insulating plate 20 are covered by one of the side parts 52 of the pair of electrodes 50. Next, the pair of electrodes 50 is heat-treated under conditions of a temperature of 170° C. and 2 hours. This improves the bonding between each of the bottoms 51 of the pair of electrodes 50 and the resistor 10. Through the above steps, the resistor A30 is manufactured.

[0076] [Modification of the third embodiment] A resistor A31 according to a modified example of the third embodiment of the present disclosure will be described with reference to Fig. 38 and Fig. 39. The resistor A31 differs from the resistor A30 described above in the configuration of the resistor body 10. Here, Fig. 38 shows the insulating plate 20 through the view for ease of understanding.

[0077] As shown in FIG. 38 and FIG. 39, the resistor 10 of the resistor A31 has a plurality of auxiliary slits 15. The plurality of auxiliary slits 15, together with the plurality of slits 11 and the plurality of grooves 12, are provided to adjust the resistance value of the resistor 10 to a predetermined value. Each of the plurality of auxiliary slits 15 penetrates the resistor 10 from the first surface 10A to the second surface 10B. Each of the plurality of auxiliary slits 15 extends in the second direction y. Due to the plurality of auxiliary slits 15, a part of each of the pair of side surfaces 10D is opened. The plurality of auxiliary slits 15 are formed in the second resistive portion 102. The length of each of the plurality of auxiliary slits 15 (dimension in the second direction y) is smaller than the length of each of the plurality of slits 11 (dimension in the second direction y). Also, a part of the insulating plate 20 enters the plurality of auxiliary slits 15 in the thickness direction z. The number of auxiliary slits 15 can be freely set according to the resistance value required for the resistor 10.

[0078] Next, the function and effect of the resistor A30 will be described.

[0079] In the resistor A30, the resistor 10 includes a pair of first resistance parts 101 spaced apart from each other in the first direction x, and a second resistance part 102 located between the pair of first resistance parts 101. Each of the pair of electrodes 50 in contact with the resistor 10 has a bottom part 51 located on the opposite side of the insulating plate 20 with respect to the resistor 10 in the thickness direction z. Each of the pair of first resistance parts 101 overlaps one of the bottom parts 51 of the pair of electrodes 50 as viewed in the thickness direction z. The maximum width w1max of the conductive path CP of each of the pair of first resistance parts 101 is smaller than the minimum width w2min of the conductive path CP of the second resistance part 102. As a result, the resistance value of the second resistance part 102 is relatively smaller than the resistance value of each of the pair of first resistance parts 101. Therefore, the amount of heat generated by the second resistance part 102 can be suppressed when the resistor A30 is used. On the other hand, when the resistor A30 is used, heat generated from each of the pair of first resistive portions 101 is released through the bottoms 51 of the pair of electrodes 50. Therefore, according to the resistor A30, it is possible to uniformly suppress the temperature rise of the resistive body 10 when the resistor A30 is used.

[0080] The resistor 10 has a plurality of slits 11 penetrating from the first surface 10A to the second surface 10B. Each of the plurality of slits 11 extends in the second direction y. The plurality of slits 11 are formed in a pair of first resistive portions 101. The second resistive portion 102 is located next to the slit 11 among the plurality of slits 11 that is located farthest from either of the pair of electrodes 50 in the first direction x. This allows the pair of first resistive portions 101 and the second resistive portion 102 in the resistor 10 to be distinguished from each other by the presence or absence of the plurality of slits 11.

[0081] In the resistor A31, the resistor 10 has an auxiliary slit 15 penetrating from the first surface 10A to the second surface 10B and extending in the second direction y. The auxiliary slit 15 is formed in the second resistive portion 102. This allows the resistance value of the resistor 10 to be set even when the resistance value required for the resistor 10 is relatively large. The length of the auxiliary slit 15 is smaller than the length of each of the multiple slits 11. This allows the minimum width w2min of the conductive path CP of the second resistive portion 102 to be prevented from becoming smaller than the maximum width w1max of the conductive path CP of each of the pair of first resistive portions 101 even when the resistor 10 has the auxiliary slit 15.

[0082] The shape of the resistor 10 is point-symmetric when viewed in the thickness direction z. This makes the resistance value of the resistor 10 constant regardless of the polarity of the pair of electrodes 50. Therefore, when mounting the resistor A30 on a wiring board, it is not necessary to check the polarity of the pair of electrodes 50.

[0083] The resistor A30 further includes a protective film 30 that is disposed on the second surface 10B of the resistive element 10 and has electrical insulation properties. Each of the bottoms 51 of the pair of electrodes 50 includes a portion that overlaps with a portion of the protective film 30 when viewed in the thickness direction z. This makes it possible to prevent a short circuit between the pair of electrodes 50 due to the influence of solder bonding when the resistor A30 is mounted on a wiring board. In addition, by making the surface area of ​​each of the bottoms 51 of the pair of electrodes 50 as large as possible within a range in which the short circuit between the pair of electrodes 50 does not occur, the heat dissipation properties of the resistor A30 can be further improved.

[0084] The resistor A30 has a covering portion 41 that covers a portion of the protective film 30, and further includes a pair of intermediate layers 40 that are spaced apart from each other in the first direction x. The pair of intermediate layers 40 are electrically connected to the resistor 10. In the resistor A30, the pair of intermediate layers 40 are made of thin metal films. Each of the covering portions 41 of the pair of intermediate layers 40 is located between the protective film 30 and one of the bottom portions 51 of the pair of electrodes 50. As a result, the bottom portions 51 of the pair of electrodes 50 that cover a portion of the protective film 30 can be formed by electrolytic barrel plating in the process shown in FIG.

[0085] Each of the pair of connecting portions 103 has a protrusion 14 protruding from one of the pair of first end faces 10C in the second direction y. The protrusion 14 is connected to one of the pair of first end faces 10C. This allows the cutting line CL to be set with the protrusion 14 as a target in the process shown in FIG. 36. In addition, the protrusion 14 increases the area of ​​the first region 13. This allows the bonding strength between the bottoms 51 of the pair of electrodes 50 and the resistor 10 to be improved. When the pair of electrodes 50 is formed by electrolytic barrel plating in the process shown in FIG. 37, the improved bonding strength makes it less likely that defects will occur in the bottoms 51 of the pair of electrodes 50.

[0086] [Fourth embodiment] A resistor A40 according to a fourth embodiment of the present disclosure will be described with reference to Figs. 40 to 44. In these figures, elements that are the same as or similar to those of the resistor A10 described above are given the same reference numerals, and duplicated explanations will be omitted. Here, Fig. 40 shows the insulating plate 20 for ease of understanding. Fig. 41 shows the pair of electrodes 50 for ease of understanding. In Fig. 41, the pair of electrodes 50 shown through the view are indicated by imaginary lines.

[0087] In the resistor A40, the configurations of the protective film 30 and the pair of intermediate layers 40 are different from those in the resistor A30 described above.

[0088] In the resistor A40, the pair of intermediate layers 40 are made of a material that is conductive and contains a synthetic resin. The pair of intermediate layers 40 contain metal particles. The metal particles contain silver. In the example shown in the resistor A40, the synthetic resin contained in the pair of intermediate layers 40 is an epoxy resin. The electrical resistivity of the pair of intermediate layers 40 is about 10 times the electrical resistivity of the resistor 10. Therefore, the electrical resistivity of the pair of intermediate layers 40 is greater than the electrical resistivity of the resistor 10.

[0089] As shown in FIG. 40, FIG. 41, and FIG. 43, each of the pair of intermediate layers 40 includes a first layer 40A and a second layer 40B. The first layer 40A has an extension 42, and is in contact with both the second surface 10B of the resistor 10 and the surface of the insulating plate 20 facing the same side as the second surface 10B. The dimension of the first layer 40A in the thickness direction z is approximately uniform throughout. The second layer 40B has a covering portion 41. The second layer 40B is connected to one of the first layers 40A of the pair of intermediate layers 40. The second layer 40B is configured to cover a part of the first layer 40A.

[0090] As shown in Fig. 41 and Fig. 42, a recess 421 is formed in each of the extending portions 42 of the pair of intermediate layers 40. The recess 421 is recessed in the first direction x from one of the pair of first end faces 10C. When viewed in the thickness direction z, the recess 421 has a rectangular shape. The first region 13 of the second surface 10B is exposed from the recess 421.

[0091] 44, each of the first layers 40A of the pair of intermediate layers 40 has an intermediate portion 43 extending from the extending portion 42 toward the protective film 30. The intermediate portion 43 includes a portion located between the resistor 10 and the protective film 30. As a result, each of both ends of the protective film 30 in the first direction x is configured to cover one of the first layers 40A of the pair of intermediate layers 40. In the resistor A40, the intermediate portion 43 is in contact with both the resistor 10 and the protective film 30.

[0092] Next, an example of a method for manufacturing the resistor A40 will be described with reference to Figures 32, 36, 37, and 45 to 47. Here, the cross-sectional positions shown in Figures 45 to 47 are the same as the cross-sectional position shown in Figure 43.

[0093] First, as shown in Fig. 32, a base material 82 is thermocompression bonded to a resistor 81 having a first surface 81A and a second surface 81B facing opposite sides in a thickness direction z. This step is the same as the step in the manufacturing method of the resistor A30, and therefore a description thereof will be omitted here.

[0094] Next, as shown in Fig. 45, first layers 40A of a pair of intermediate layers 40 are formed to cover a portion of each of the second surface 81B of the resistor 81 and the surface of the base material 82 facing the same side as the second surface 81B. The first layers 40A of the pair of intermediate layers 40 are formed by applying a material containing silver particles and epoxy resin by screen printing to both the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B. At this time, the material is applied while being spaced apart from each other in the first direction x. Thereafter, the material is thermally cured to form the first layers 40A of the pair of intermediate layers 40.

[0095] 46, a protective film 30 is formed to cover the second surface 81B of the resistor 81 and a portion of the surface of the base material 82 facing the same side as the second surface 81B. First, a material containing an epoxy resin is applied by screen printing to the second surface 81B and the surface of the base material 82 facing the same side as the second surface 81B. At this time, each of both ends of the material in the first direction x is made to cover one of the first layers 40A of the pair of intermediate layers 40. Thereafter, the material is thermally cured to form the protective film 30.

[0096] Next, as shown in FIG. 47, the second layer 40B of the pair of intermediate layers 40 is formed to cover a part of the protective film 30. First, a material containing silver particles and an epoxy resin is applied to the protective film 30 by screen printing. At this time, the material is applied while being spaced apart from each other in the first direction x. In addition, each part of the material that is spaced apart from each other is made to cover a part of one of the first layers 40A of the pair of intermediate layers 40. Thereafter, the material is thermally cured to form the second layer 40B of the pair of intermediate layers 40.

[0097] 36, the resistor 81 and the substrate 82 are cut along cutting lines CL with a dicing blade to separate them into individual pieces including the protective film 30 and a pair of intermediate layers 40 (first layer 40A and second layer 40B). This step is the same as the step in the manufacturing method of the resistor A30, and therefore a description thereof will be omitted here.

[0098] Finally, a pair of electrodes 50 in contact with the resistor 10 is formed as shown in Fig. 37. This step is the same as the step in the manufacturing method of the resistor A30, so a description thereof will be omitted here. Through the above steps, the resistor A40 is manufactured.

[0099] Next, the function and effect of resistor A40 will be described.

[0100] In the resistor A40, the resistor 10 includes a pair of first resistance parts 101 spaced apart from each other in the first direction x, and a second resistance part 102 located between the pair of first resistance parts 101. Each of the pair of electrodes 50 in contact with the resistor 10 has a bottom part 51 located on the opposite side of the insulating plate 20 with respect to the resistor 10 in the thickness direction z. Each of the pair of first resistance parts 101 overlaps one of the bottom parts 51 of the pair of electrodes 50 as viewed in the thickness direction z. The maximum width w1max of the conductive path CP of each of the pair of first resistance parts 101 is smaller than the minimum width w2min of the conductive path CP of the second resistance part 102. Therefore, the resistor A40 also makes it possible to uniformly suppress the temperature rise of the resistor 10 when using the resistor A40.

[0101] In the resistor A40, the pair of intermediate layers 40 are made of a material including a synthetic resin containing metal particles. As a result, the protective film 30 and the pair of intermediate layers 40 are both configured to include the same type of material, which can improve the bonding between the protective film 30 and the covering portion 41 of the pair of intermediate layers 40. In addition, the pair of intermediate layers 40 have conductive physical properties, so that the pair of intermediate layers 40 can be electrically connected to the resistor 10.

[0102] In the resistor A40, the electrical resistivity of the pair of intermediate layers 40 is greater than the electrical resistivity of the resistor 10. As a result, when the resistor A40 is in use, the current flowing through the resistor 10 is less likely to flow through the pair of intermediate layers 40. Therefore, fluctuations in the resistance value of the resistor A40 due to the influence of the pair of intermediate layers 40 can be suppressed.

[0103] The present disclosure is not limited to the above-described embodiment. The specific configuration of each part of the present disclosure can be freely designed in various ways.

[0104] Various embodiments of the present disclosure include the following caveats.

[0105] Appendix 1A. A resistor having a first surface and a second surface facing opposite each other in a thickness direction; An insulating plate disposed on the first surface; A protective film disposed on the second surface; a pair of electrodes arranged apart from each other in a first direction perpendicular to the thickness direction and in contact with the resistor; each of the pair of electrodes has a bottom portion located on an opposite side of the resistor body from the insulating plate in the thickness direction; the bottom portions of the pair of electrodes overlap a portion of the protective film when viewed in the thickness direction, The insulating film further includes a pair of intermediate layers that are electrically conductive, made of a material containing a synthetic resin, and that are spaced apart from each other in the first direction; each of the pair of intermediate layers has a covering portion that covers a part of the protective film; A resistor, wherein each of the covering portions of the pair of intermediate layers is located between the protective film and one of the bottom portions of the pair of electrodes.

[0106] Appendix 2A. The protective film is made of a material containing a synthetic resin; 4. The resistor of claim 1A, wherein the pair of intermediate layers contain metal particles.

[0107] Clause 3A. The resistor of Clause 2A, wherein the metal particles comprise silver.

[0108] Appendix 4A. The resistor of any one of Appendixes 2A and 3A, wherein the pair of intermediate layers has a greater electrical resistivity than the resistor body.

[0109] Appendix 5A. The resistor according to any one of Appendixes 2A to 4A, wherein the protective film contains a filler made of a material including ceramics.

[0110] Addendum 6A. The resistor is made of a metal plate; the resistor has a slit penetrating from the first surface to the second surface, The resistor of any one of Appendixes 2A to 5A, wherein the slits extend in a second direction perpendicular to both the thickness direction and the first direction.

[0111] Addendum 7A. The insulating plate is made of a material containing synthetic resin; The resistor of claim 6A, wherein a portion of the insulating plate extends into the slit in the thickness direction.

[0112] Addendum 8A. The slit has a pair of side walls spaced apart in the first direction; The resistor of claim 7A, wherein each of the pair of side walls includes a portion that is concave toward the first direction.

[0113] Addendum 9A. The resistor has a plurality of grooves recessed from the second surface and extending in a predetermined direction; 8B. The resistor of any one of claims 6A to 8A, wherein the protective film is in engagement with the plurality of grooves.

[0114] Addendum 10A. The resistor has a pair of first end faces connected to both the first surface and the second surface and spaced apart from each other in the first direction; Each of the pair of electrodes has a side portion connected to one of the bottom portions of the pair of electrodes and standing in the thickness direction, The resistor of any one of Appendixes 6A to 9A, wherein each of the side portions of the pair of electrodes contacts one of the pair of first end surfaces.

[0115] Addendum 11A. The insulating plate has a pair of second end surfaces facing opposite each other in the first direction and spaced apart from each other; The resistor of claim 10A, wherein each of the side portions of the pair of electrodes contacts one of the pair of second end surfaces.

[0116] Appendix 12A. The resistor of Appendix 11A, wherein each of the pair of second end faces is flush with one of the pair of first end faces.

[0117] Addendum 13A. The protective film is located inward in the first direction from the pair of first end surfaces when viewed in the thickness direction, the second surface includes a first region that is located between one of the pair of first end surfaces and the protective film when viewed in the thickness direction and is not covered by the pair of intermediate layers, The resistor of any one of Appendixes 10A to 12A, wherein each of the bottom portions of the pair of electrodes contacts the first region.

[0118] Addendum 14A. Each of the pair of intermediate layers has an extension portion extending from one of the covering portions of the pair of intermediate layers to one of the pair of first end surfaces; The extension portion is in contact with the second surface, The resistor of claim 13A, wherein each of the bottom portions of the pair of electrodes contacts one of the extension portions of the pair of intermediate layers.

[0119] Addendum 15A. Each of the extending portions of the pair of intermediate layers has a recess recessed from one of the pair of first end faces toward the first direction, The resistor of claim 14A, wherein the first region is exposed from the recess.

[0120] Addendum 16A. Each of the pair of intermediate layers includes a first layer and a second layer; The first layer has the extension portion, The resistor of any one of claims 14A and 15A, wherein the second layer has the coating portion and is connected to one of the first layers of the pair of intermediate layers.

[0121] Addendum 17A. Each of the first layers of the pair of intermediate layers has an intermediate portion extending from the extension portion toward the protective film, The resistor according to claim 16A, wherein the interposed portion includes a portion located between the resistive element and the protective film.

[0122] Appendix 1B. A resistor having a first surface facing a thickness direction; An insulating plate disposed on the first surface; a pair of electrodes arranged apart from each other in a first direction perpendicular to the thickness direction and in contact with the resistor; each of the pair of electrodes has a bottom portion located on an opposite side of the resistor body from the insulating plate in the thickness direction; the resistor includes a pair of first resistance portions spaced apart from each other in the first direction, a second resistance portion located between the pair of first resistance portions, and a pair of connection portions in contact with the pair of electrodes and connected to the pair of first resistance portions, each of the pair of first resistors overlaps one of the bottom portions of the pair of electrodes when viewed in the thickness direction; A resistor, wherein a maximum width of a conductive path of each of the pair of first resistor portions is smaller than a minimum width of a conductive path of the second resistor portion.

[0123] Addendum 2B. The resistor has a second surface facing opposite the first surface; the resistor has a plurality of slits penetrating from the first surface to the second surface and extending in a second direction perpendicular to both the thickness direction and the first direction; The plurality of slits are formed in the pair of first resistor portions, The resistor according to claim 1B, wherein the second resistive portion is located next to one of the plurality of slits that is located farthest in the first direction from either of the pair of electrodes.

[0124] Addendum 3B. The resistor has an auxiliary slit penetrating from the first surface to the second surface and extending in the second direction; The auxiliary slit is formed in the second resistor portion, The resistor of claim 2B, wherein a length of the auxiliary slit is less than a length of each of the plurality of slits.

[0125] Appendix 4B. The resistor according to Appendix 2B or 3B, wherein the shape of the resistor element is point symmetric when viewed in the thickness direction.

[0126] Addendum 5B. The resistor has a pair of end faces connected to both the first surface and the second surface and spaced apart from each other in the first direction; Each of the pair of electrodes has a side portion connected to one of the bottom portions of the pair of electrodes and standing in the thickness direction, 4C. The resistor of claim 2B, wherein each of the side portions of the pair of electrodes contacts one of the pair of end faces.

[0127] Appendix 6B. The resistor of Appendix 5B, wherein each of the sides of the pair of electrodes contacts the insulating plate.

[0128] Addendum 7B. The resistor has a pair of side surfaces connected to both the first surface and the second surface and spaced apart from each other in the second direction; the insulating plate is made of a material containing a synthetic resin, The resistor according to claim 5B or 6B, wherein the pair of side surfaces are covered by the insulating plate.

[0129] Appendix 8B. The resistor of Appendix 7B, wherein a portion of the insulating plate extends into the plurality of slits in the thickness direction.

[0130] Addendum 9B. Each of the plurality of slits has a pair of side walls spaced apart from each other in the first direction; The resistor of claim 8B, wherein each of the pair of side walls includes a portion recessed in the first direction.

[0131] Addendum 10B. Each of the pair of connecting portions has a protrusion protruding from one of the pair of side surfaces in the second direction, The resistor of any one of Appendixes 7B to 9B, wherein the protrusion is connected to one of the pair of end faces.

[0132] Addendum 11B. The optical fiber further comprises a protective film disposed on the second surface, the protective film is made of a material containing a synthetic resin, The resistor according to any one of Appendixes 5B to 10B, wherein each of the bottom portions of the pair of electrodes includes a portion that overlaps a part of the protective film when viewed in the thickness direction.

[0133] Appendix 12B. The resistor of Appendix 11B, wherein the protective film contains a filler made of a material including ceramics.

[0134] Addendum 13B. The resistor has a plurality of grooves recessed from the second surface and extending in a predetermined direction; 13. The resistor of claim 11B or 12B, wherein the protective film is in engagement with the plurality of grooves.

[0135] Addendum 14B. The optical fiber further includes a pair of intermediate layers having a covering portion that covers a part of the protective film and spaced apart from each other in the first direction; The pair of intermediate layers are electrically connected to the resistor, The resistor according to any one of appendices 11B to 13B, wherein each of the covering portions of the pair of intermediate layers is located between the protective film and one of the bottom portions of the pair of electrodes.

[0136] Addendum 15B. The protective film is located inward in the first direction from the pair of end surfaces when viewed in the thickness direction, the second surface includes a first region that is located between one of the pair of end surfaces and the protective film when viewed in the thickness direction and is not covered by the pair of intermediate layers, The resistor of claim 14B, wherein each of the bottom portions of the pair of electrodes contacts the first region.

[0137] Appendix 16B. The resistor of Appendix 15B, wherein the pair of intermediate layers are made of a thin metal film.

[0138] Addendum 17B. The pair of intermediate layers are made of a material including a synthetic resin containing metal particles; The resistor of claim 15B, wherein the pair of intermediate layers have a greater electrical resistivity than a greater electrical resistivity of the resistor body.

Claims

1. a resistor having a first surface and a second surface facing opposite to each other in a thickness direction; An insulating plate disposed on the first surface; a pair of electrodes spaced apart from each other in a first direction perpendicular to the thickness direction and in contact with the resistor; each of the pair of electrodes has a bottom portion located on the opposite side of the resistor from the insulating plate in the thickness direction; the resistor includes a pair of first resistance portions spaced apart from each other in the first direction, a second resistance portion located between the pair of first resistance portions, and a pair of connection portions in contact with the pair of electrodes and connected to the pair of first resistance portions, When viewed in the thickness direction, each of the pair of first resistors overlaps one of the bottom portions of each of the pair of electrodes, a maximum width of a conductive path of each of the pair of first resistor portions is smaller than a minimum width of a conductive path of the second resistor portion; the resistor has a plurality of slits penetrating from the first surface to the second surface and extending in a second direction perpendicular to both the thickness direction and the first direction, The plurality of slits are formed in the pair of first resistor portions, the second resistor portion is located adjacent to one of the plurality of slits that is located farthest from either of the pair of electrodes in the first direction, each of the pair of connection portions has an end surface facing a side opposite to a side on which the pair of first resistance portions are located in the first direction; Each of the pair of electrodes has a side portion connected to the bottom portion and standing in the thickness direction, the side portions of each of the pair of electrodes are in contact with the end surfaces of the pair of connection portions, each of the pair of connecting portions has a pair of side surfaces facing opposite sides in the second direction and a projection projecting in the second direction from one of the pair of side surfaces; the protrusion is connected to one of the end surfaces of the pair of connection parts, each of the pair of connection portions is sandwiched between a boundary between the protrusion and one of the pair of side surfaces and the end surface in the first direction, and includes a region that includes the entire protrusion; A resistor, wherein a dimension of the region in the second direction gradually increases from the boundary to the end face.

2. The resistor has an auxiliary slit penetrating from the first surface to the second surface and extending in the second direction, The auxiliary slit is formed in the second resistor portion, The resistor of claim 1 , wherein the length of the auxiliary slit is less than the length of each of the plurality of slits.

3. A resistor as described in claim 1 or 2, wherein when viewed in the thickness direction, the shape of the resistor is point symmetric.

4. A resistor as described in any one of claims 1 to 3, wherein the side portions of each of the pair of electrodes are in contact with the insulating plate.

5. The insulating plate is made of a material containing a synthetic resin, 5. The resistor according to claim 1, wherein the pair of side surfaces of each of the pair of connection portions are covered with the insulating plate.

6. A resistor as described in claim 5, wherein a portion of the insulating plate is recessed into the multiple slits.

7. Each of the plurality of slits has a pair of side walls spaced apart from each other in the first direction, The resistor according to claim 6 , wherein each of the pair of side walls includes a portion recessed in the first direction.

8. Further comprising a protective film disposed on the second surface, the protective film is made of a material containing a synthetic resin, The resistor according to claim 1 , wherein the bottom portion of each of the pair of electrodes overlaps the protective film when viewed in the thickness direction.

9. The resistor of claim 8, wherein the protective film contains a filler made of a material including ceramics.

10. The resistor has a plurality of grooves recessed from the second surface and extending in a predetermined direction, The resistor of claim 8 or 9, wherein the protective film is in engagement with the plurality of grooves.

11. A coating portion that covers a portion of the protective film, and further comprising a pair of intermediate layers spaced apart from each other in the first direction, The pair of intermediate layers are electrically connected to the resistor, 11. The resistor according to claim 8, wherein the covering portion of each of the pair of intermediate layers is located between the protective film and one of the bottom portions of each of the pair of electrodes.

12. When viewed in the thickness direction, the protective film is located inward in the first direction relative to the pair of end faces, When viewed in the thickness direction, the second surface includes a first region that is located between any one of the pair of end surfaces and the protective film and is exposed from the pair of intermediate layers, The resistor of claim 11 , wherein the bottom of each of the pair of electrodes contacts the first region.

13. The resistor of claim 12, wherein the pair of intermediate layers are made of thin metal films.

14. The pair of intermediate layers are made of a material including a synthetic resin containing metal particles, The resistor of claim 13 , wherein the pair of intermediate layers have a greater electrical resistivity than the resistor body.

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