Composite materials

Abstract

To provide a composite member that comprises an insulation spacer having a creepage withstanding voltage equal to or higher than that of the conventional art even in an AC apparatus in the atmosphere, and that can miniaturize a high-voltage device and improve the insulation reliability.SOLUTION: A composite member comprises: a first conductor; a second conductor arranged at a predetermined interval from the first conductor, having a potential different from that of the first conductor; and an insulation spacer that supports the first and second conductors. For the insulation spacer, a convexo-concave part having a length equal to or more than 1 / 100 of a length along the creepage of the insulation spacer is formed at a portion located between the first and second conductors.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite member, and more particularly to a composite member comprising a conductor and an insulating spacer, suitable for use in high-voltage devices such as patterned substrates for power modules. [Background technology]

[0002] For example, in high-voltage devices such as patterned substrates for power modules, insulating spacers are used to provide structural support between conductors having different potentials and to prevent short circuits (dielectric breakdown) between the conductors.

[0003] In such a structure, an electric field is concentrated at the triple point where the conductor, insulating spacer, and space meet, and the triple point where the electric field is concentrated becomes a weak point in the insulation and becomes the starting point of discharge.

[0004] Therefore, compared to when insulation is achieved only by space between conductors, which is prone to discharge and breakdown, when insulation is achieved by the surface of an insulating spacer, discharge is more likely to occur due to the electric field at the triple point, and in order to prevent breakdown, a large insulating distance is required, which may result in the device becoming larger.

[0005] For this reason, Patent Document 1, a prior art document, describes the manufacture of spacers with 1 to 10 μm of unevenness on the spacer surface to suppress charging of the spacers, and an image drawing device that uses this.

[0006] According to Patent Document 1, when a DC voltage is applied in a vacuum, electrons can be trapped in the recesses of the unevenness formed on the spacer surface, which has the effect of suppressing charging. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-243274 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the "spacer having 1 to 10 μm irregularities on the spacer surface" described in Patent Document 1 mentioned above is intended to suppress charging in a vacuum, and is therefore insufficient for structurally mitigating the electric field. Furthermore, in AC devices in the atmosphere, where the influence of charging is low, there is a risk that it will not be sufficiently effective in suppressing partial discharge and dielectric breakdown from the standpoint of insulation.

[0009] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a composite member that is equipped with an insulating spacer that has a surface withstand voltage higher than conventional ones, even when used in AC equipment in the atmosphere, thereby enabling the miniaturization of high-voltage equipment and improving insulation reliability. [Means for solving the problem]

[0010] In order to achieve the above object, the composite member of the present invention is a composite member comprising a first conductor, a second conductor arranged at a predetermined distance from the first conductor and having a potential different from that of the first conductor, and an insulating spacer supporting the first conductor and the second conductor, wherein the insulating spacer has an uneven portion formed in a portion located between the first conductor and the second conductor, the uneven portion having a length equal to or greater than 1 / 100 of the length along the creeping surface of the insulating spacer. At the same time, an air layer is provided inside the insulating spacer and at least in the convex portions of the concave-convex portion. It is characterized by: [Effects of the Invention]

[0011] According to the present invention, even in atmospheric AC equipment, an insulating spacer having a creepage withstand voltage higher than that of conventional equipment is provided, and high voltage equipment can be made smaller and insulation reliability can be improved. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing Example 1 of a composite material according to the present invention. [Figure 2] 2 is a characteristic diagram showing the results of calculations performed by electric field analysis on the effect of reducing a surface electric field due to the structure of the concave-convex portion in Example 1 of the composite member of the present invention shown in FIG. 1. FIG. [Figure 3] FIG. 3 is a cross-sectional view showing Example 2 of a composite material according to the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing Example 3 of a composite material according to the present invention. [Figure 5] FIG. 10 is a cross-sectional view showing Example 4 of the composite material of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing Example 5 of a composite material according to the present invention. [Figure 7] FIG. 10 is a cross-sectional view showing Example 6 of a composite material according to the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing Example 7 of a composite material according to the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing Example 8 of a composite material according to the present invention. [Figure 10] FIG. 10 is a perspective view showing an example of an insulating spacer as Example 9 of a composite member of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The composite member of the present invention will be described below based on the illustrated embodiments. In each embodiment described below, the same components are designated by the same reference numerals, and repeated description thereof will be omitted. [Example]

[0014] Example 1 of the composite material of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of the composite material in this example.

[0015] As shown in Figure 1, the composite member of this embodiment is roughly composed of a first conductor 1, a second conductor 2 having a different potential from the first conductor 1, and an insulating spacer 100 that supports the first and second conductors 1 and 2.

[0016] In the composite member of this embodiment, in order to provide insulation between the first and second conductors 1 and 2, the insulating spacer 100 has a square uneven portion 10 consisting of a recess 11 and a protrusion 12 formed in the portion located between the first conductor 1 and the second conductor 2, and furthermore, this uneven portion 10 is formed so that its length is 1 / 100 or more of the length along the surface of the insulating spacer 100.

[0017] That is, as shown in FIG. 1, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100.

[0018] The insulating spacer 100 is likely to be made of general-purpose plastics such as ABS (acrylonitrile butadiene styrene) resin, epoxy resin, nylon resin, PPS (polyphenylene sulfide), polycarbonate, or ceramics such as alumina, SiC, or SiN.

[0019] Composite materials using these resins as the main component with fillers added are also acceptable. Furthermore, these materials can be produced using a 3D printer depending on the processing precision. The 3D printer referred to here can be any of the following types: fused deposition model, inkjet model, stereolithography model, powder model, sheet lamination model, etc.

[0020] The first and second conductors 1 and 2 are placed and supported on an insulating spacer 100, and may be electrodes to which a high voltage is applied, electrodes electrically connected to ground, metallization with evaporated metal, pattern wiring, etc.

[0021] Incidentally, an electric field is concentrated at the first triple junction S1 where the insulating spacer 100, the first conductor 1, and the recess 11 meet, and at the second triple junction S2 where the insulating spacer 100, the second conductor 2, and the recess 11 meet. When the potential difference between the first conductor 1 and the second conductor 2 becomes large, a local discharge (partial discharge) occurs on the surface of the insulating spacer 100 near the first and second conductors 1 and 2. In order to suppress this local discharge (partial discharge) and improve the withstand voltage of the insulating spacer 100, it is important to reduce the electric fields at the first and second triple junctions S1 and S2.

[0022] In the composite member of this embodiment, the insulating spacer 100 has an uneven portion 10 to control the electric field on the surface, but in particular, in order to reduce the electric field on the surface at the first and second triple junctions S1 and S2, it is desirable to form a recess 11 in the insulating spacer 100 on the first and second triple junctions S1 and S2 sides of the first and second conductors 1 and 2 and the insulating spacer 100.

[0023] This allows the creeping electric field between the first conductor 1 and the second conductor 2, starting from the first and second triple points S1 and S2 between the insulating spacer 100 and the first and second conductors 1 and 2, to be horizontal (the first triple point S1 where the first conductor 1 meets the insulating spacer 100 and the recess 11, and the second triple point S2 where the second conductor 2 meets the insulating spacer 100 and the recess 11 are both horizontal in the vertical direction), thereby reducing the creeping electric field.

[0024] Furthermore, if the uneven portion 10 is extremely small (short), the effect of reducing the electric field is low and an improvement in the partial discharge voltage cannot be expected. Therefore, as described above, the length (L) of the uneven portion 10 that is effective in improving the partial discharge voltage is desirably 1 / 100 or more of the length along the surface of the insulating spacer 100 (the distance between the electrodes).

[0025] FIG. 2 shows the results of calculations performed by electric field analysis on the effect of reducing the creeping electric field due to the structure of the uneven portion 10 in the composite member of this example.

[0026] The horizontal axis of Fig. 2 represents the ratio of the size of the uneven portion 10 when the insulation distance when the uneven portion 10 is not present is set to 1. The vertical axis of Fig. 2 represents the electric field when the uneven portion 10 is present when the electric field when the uneven portion 10 is not present is set to 100%.

[0027] As can be seen from Figure 2, when the uneven portion 10 is small, the electric field reduction effect is small, but when the uneven portion 10 is approximately 1 / 100 or more in length, the electric field can be greatly reduced. Therefore, it is preferable that the length (L) of the uneven portion 10 be 1 / 100 to 1 of the length along the surface of the insulating spacer 100 (the distance between the electrodes).

[0028] An example of a high-voltage device to which the composite member of this embodiment is applied is a pattern substrate such as a power module.

[0029] It is necessary to ensure insulation on the surface of the substrate against potential differences between the pattern wiring on the pattern board, but by adopting the composite member of this embodiment, it is possible to increase the insulation distance on the surface for the same distance between the pattern wiring, as well as alleviate the electric field and improve the withstand voltage.

[0030] According to this embodiment, the electric field generated on the surface of the insulating spacer 100 near the first and second conductors 1 and 2 can be alleviated, and by providing the insulating spacer 100 with a surface withstand voltage higher than that of conventional AC equipment even in the atmosphere, it is possible to miniaturize high-voltage equipment and improve insulation reliability. [Example]

[0031] A second embodiment of the composite material of the present invention will be described with reference to FIG.

[0032] In Example 1 shown in Figure 1, a square uneven portion 10 was provided on the surface of the insulating spacer 100, but in this example shown in Figure 3, a tapered portion 13 is formed on the side 11a of the recess 11 of the uneven portion 10 of the insulating spacer 100, so that the recess 11 becomes wider as it approaches the bottom 11b of the recess 11, and this is different from Example 1 in that the cross-sectional shape of the recess 11 and the protrusion 12 is configured to be approximately triangular.

[0033] 3, in this embodiment, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100. The other configurations are the same as those in the first embodiment.

[0034] Typically, the electric field on the surface of the insulating spacer 100 is formed when equipotential lines formed by the first conductor 1, the second conductor 2 and the insulating spacer 100 intersect with the surface of the insulating spacer 100.

[0035] Therefore, by providing a tapered portion 13 in the uneven portion 10 of the insulating spacer 100 and forming the length (L) of the uneven portion 10 to be 1 / 100 or more of the length along the surface of the insulating spacer 100, the surface of the insulating spacer 100 can be made closer to being parallel to the equipotential lines formed between the first conductor 1 and the second conductor 2, and the surface electric field of the insulating spacer 100 can be reduced.

[0036] Even with this configuration of the present embodiment, the same effects as those of the first embodiment can be obtained. [Example]

[0037] A third embodiment of the composite material of the present invention will be described with reference to FIG.

[0038] Example 3 shown in Figure 4 differs from Example 1 in that the convex portions 12 of the rectangular uneven portion 10 on the surface of the insulating spacer 100 described in Example 1 are formed on the insulating spacer 100 on the first triple point S3 side where the triple point of the first conductor 1, the insulating spacer 100, and the atmosphere come into contact, and on the second triple point S4 side where the second conductor 2, the insulating spacer 100, and the atmosphere come into contact, and further, these convex portions 12 are configured to be higher than the first triple point S3 and the second triple point S4.

[0039] 4, in this embodiment, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100. The other configurations are the same as those in the first embodiment.

[0040] Normally, when insulating conductors in high-voltage equipment, it is necessary to prevent both partial discharge and dielectric breakdown. To prevent partial discharge, it is important to mitigate the electric field concentration near the electrodes. To prevent dielectric breakdown, it is important to lengthen the path of discharge propagation in addition to mitigating the electric field. The path of discharge propagation follows the electric field lines formed between the electrodes.

[0041] In this embodiment, a convex portion 12 is formed on the insulating spacer 100 on the side of the first triple junction S3 where the first conductor 1, the insulating spacer 100, and the atmosphere come into contact, and on the side of the second triple junction S4 where the second conductor 2, the insulating spacer 100, and the atmosphere come into contact, and further, this convex portion 12 is configured to be higher than the first triple junction S3 and the second triple junction S4.

[0042] With this configuration, the electric lines of force formed between the first conductor 1 and the second conductor 2 intersect with the protrusions 12, making it possible to suppress the progress of discharge.

[0043] Even with this configuration of the present embodiment, the same effects as those of the first embodiment can be obtained. [Example]

[0044] Example 4 A composite material according to a fourth embodiment of the present invention will be described with reference to FIG.

[0045] In Example 4 shown in Figure 5, a recess 11 lower than the first and second triple points S5 and S6 is formed adjacent to the first triple point S5 where the insulating spacer 100, the first conductor 1, and the recess 11 meet, and a second triple point S6 where the insulating spacer 100, the second conductor 2, and the recess 11 meet, and a protrusion 12 higher than the first and second triple points S5 and S6 is formed next to this recess 11.

[0046] 5, in this embodiment, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100. The other configurations are the same as those in the first embodiment.

[0047] Even with the configuration of this embodiment, it is possible to suppress both partial discharge and dielectric breakdown, and it is possible to obtain the same effects as in the first embodiment. [Example]

[0048] A composite member according to a fifth embodiment of the present invention will be described with reference to FIG.

[0049] In the above-mentioned Examples 1 and 2, an uneven portion 10 is formed on the surface of the insulating spacer 100, and the length (L) of the uneven portion 10 is set to 1 / 100 or more of the length along the surface of the insulating spacer 100, thereby reducing the electric field near the electrode.

[0050] In order to reduce the electric field, it is desirable for the uneven portion 10 to be large, but if the size of the uneven portion 10 is limited due to factors other than insulation, such as constraints on high-voltage equipment, it may not be possible to achieve a sufficient electric field reduction effect.

[0051] Therefore, in this embodiment, as shown in FIG. 6, an air layer 14 is provided in the protrusion 12 inside the insulating spacer 100.

[0052] 6, in this embodiment, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100. The other configurations are the same as those in the first embodiment.

[0053] Generally, in composite insulation consisting of two different types of insulators, such as an insulator and space, the greater the difference in the dielectric constant between the insulator and space, the more the electric field concentrates in the medium with the lower dielectric constant. In particular, when comparing solid insulators with air, the dielectric constant and breakdown voltage of air are lower than those of solid insulators, making it easier for the electric field to concentrate and for discharge to occur.

[0054] Therefore, by providing an air layer 14 in the convex portion 12 inside the insulating spacer 100 and forming the length (L) of the concave-convex portion 10 to be 1 / 100 or more of the length along the surface of the insulating spacer 100, the difference in dielectric constant between the solid insulator and the air is reduced, and electric field concentration in the air is alleviated, thereby improving the insulating performance as a composite insulation.

[0055] Furthermore, depending on the shape and configuration of the conductors, the air layer 14 may be provided only in the uneven portion 10 located near one or both of the conductors, and there may be uneven portions 10 that do not include the air layer 14.

[0056] In this embodiment, as shown in Figure 6, an air layer 14 is arranged in the protrusion 12 inside the insulating spacer 100, which makes it possible to bring the dielectric constant of the solid insulator closer to that of space, thereby reducing the electric field in the space and suppressing discharge.

[0057] Even with this configuration of the present embodiment, the same effects as those of the first embodiment can be obtained. [Example]

[0058] Example 6 A composite material according to a sixth embodiment of the present invention will be described with reference to FIG.

[0059] In the above-mentioned Example 1, the first and second conductors 1 and 2 were arranged on the surface of the insulating spacer 100, but in the present Example shown in Figure 7, the insulating spacer 100 is sandwiched between the top and bottom of the first conductor 1 and the second conductor 2, and there are convex portions 12 at the first triple point S7 where the first conductor 1, the insulating spacer 100, and the atmosphere meet, and at the second triple point S8 where the second conductor 2, the spacer 100, and the atmosphere meet, and there are concave portions 11 formed adjacent to the triple points S7 and S8, more inward of the insulating spacer 100. This is different from Examples 1-5.

[0060] In this embodiment as well, as shown in FIG. 7, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100.

[0061] As shown in Example 1 of Figure 1, when the first and second conductors 1 and 2 are arranged on the surface of the insulating spacer 100, by providing a recess 11 at the first and second triple junctions S1 and S2 of the insulating spacer 100 and the first and second conductors 1 and 2, the creeping surface of the insulating spacer 100 at the first and second triple junctions S1 and S2 is perpendicular to the space between the first and second conductors 1 and 2 (the creeping surface of the insulating spacer 100 at the first triple junction S1 where the insulating spacer 100, the first conductor 1, and the recess 11 meet, and at the second triple junction S2 where the insulating spacer 100, the second conductor 2, and the recess 11 meet is perpendicular (vertical) to the space between the first and second conductors 1 and 2), thereby reducing the electric field on the surface.

[0062] In the configuration of this embodiment, regardless of whether the first and second conductors 1 and 2 are in contact with the recessed portion 11 or the protruding portion 12, the creeping surface is parallel to the space between the first and second conductors 1 and 2 (i.e., the creeping surface is parallel to the vertical direction between the first and second conductors 1 and 2). When the uneven portion 10 is configured to be continuous, the recessed portion 11 becomes a space and the protruding portion 12 becomes a solid insulator, so that the electric field is concentrated in the recessed portion 11, which has a low dielectric constant.

[0063] For this reason, in the configuration of this embodiment shown in Figure 7, the convex portion 12 with a low electric field is positioned so as to be in contact with the first and second conductors 1 and 2, and the concave portion 11 is positioned adjacent to it and further inward of the insulating spacer 100 than the first and second triple points S7 and S8, and furthermore, the length (L) of the concave portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100, thereby mitigating the electric field at the triple points S7 and S8 and suppressing discharge.

[0064] According to this embodiment, the electric field generated on the surface of the insulating spacer 100 near the first and second conductors 1 and 2 can be alleviated, and by providing the insulating spacer 100 with a surface withstand voltage higher than that of conventional AC equipment even in the atmosphere, it is possible to miniaturize high-voltage equipment and improve insulation reliability. [Example]

[0065] A seventh embodiment of the composite material of the present invention will be described with reference to FIG.

[0066] Example 7 shown in Figure 8 has a structure in which a convex portion 15 is formed in the middle of the insulating spacer 100, the convex portion 15 being higher than the convex portion 12 of the uneven portion 10 formed on the first triple point S7 side where the first conductor 1, the insulating spacer 100, and the atmosphere come into contact, and on the second triple point S8 side where the second conductor 2, the insulating spacer 100, and the atmosphere come into contact, and at a position farther away from the first and second conductors 1 and 2 than the convex portion 12.

[0067] In this embodiment, the length (L1 and L2) of the uneven portion 10 is formed to be 1 / 100 or more of the length along the surface of the insulating spacer 100. The other configurations are the same as those in the sixth embodiment.

[0068] As a result, there is a high convex portion 15 outside the first and second triple junctions S7 and S8, which can alleviate the electric field at the first and second triple junctions S7 and S8 while suppressing the progress of discharge generated from the first and second triple junctions S7 and S8.

[0069] An example of a high-voltage device in this embodiment is a high-voltage generator, in which a high-voltage terminal to which a desired voltage is applied is electrically insulated from a housing connected to ground potential by an insulating spacer and mechanically supported.

[0070] By providing the protrusions 12 and 15 as in this embodiment on the creeping surface of this insulating spacer, it becomes possible to alleviate the electric field at the first and second triple points S7 and S8, and improve the withstand voltage.

[0071] Even with this configuration of the present embodiment, the same effects as those of the sixth embodiment can be obtained. [Example]

[0072] Example 8 of the composite material of the present invention will be described with reference to FIG.

[0073] In the composite member of this embodiment shown in Figure 9, the insulating spacer 100 consists of a first insulating spacer 101 without an uneven portion 10 and a second insulating spacer 102 with an uneven portion 10 processed therein, and differs from Example 6 shown in Figure 7 in that the first insulating spacer 101 without an uneven portion 10 and the second insulating spacer 102 with an uneven portion 10 processed therein are fixed together with adhesive 200.

[0074] In this embodiment as well, the length (L) of the uneven portion 10 is formed to be 1 / 100 or more of the length of the insulating spacer 100 along the creeping surface.

[0075] Normally, the insulating spacer 100 serves both the role of insulation and supporting the conductor, but if the material of the insulating spacer 100 is selected based on mechanical strength, etc., it may become difficult to process the uneven portion 10.

[0076] Therefore, in the present embodiment shown in Figure 9, a first insulating spacer 101 that does not have the uneven portion 10, which is difficult to process, and a second insulating spacer 102 that can have the uneven portion 10 processed on its surface are separately manufactured, and the first insulating spacer 101 that does not have the uneven portion 10 and the second insulating spacer 102 that has the uneven portion 10 processed on its surface are fixed together with an adhesive 200.

[0077] With the configuration of this embodiment, it is possible to obtain the same effect as in embodiment 6, and even if a material that is difficult to process is selected as the insulating spacer 100, it is possible to obtain the effect of forming an uneven portion 10 on the surface of the insulating spacer 100.

[0078] It goes without saying that the configuration of this embodiment can be applied to embodiments 1 to 7. [Example]

[0079] As a ninth embodiment of the composite member of the present invention, the details of an insulating spacer 100 will be described with reference to FIG.

[0080] The insulating spacer 100 of this embodiment shown in FIG. 10 shows a three-dimensional structure of the first and second conductors 1 and 2 and the insulating spacer 100.

[0081] As shown in Figure 10, the uneven portion 10 adjacent to the first conductor 1 has a structure that follows the first triple point S1 between the first conductor 1 and the insulating spacer 100, and the uneven portion 20 consisting of the recessed portion 21 and the protruding portion 21 adjacent to the second conductor 2 has a structure that follows the second triple point S2 between the second conductor 2 and the insulating spacer 100.

[0082] When reducing the electric field between the first and second conductors 1 and 2 and the first and second triple points S1 and S2 of the insulating spacer 100, it is desirable that the uneven portions 10 and 20 are also configured to match the shapes of the first and second conductors 1 and 2. For example, if the conductor shapes of the first and second conductors 1 and 2 are different and asymmetric, it is desirable that the uneven portion 10 also have an asymmetric structure to match the shapes of the first and second conductors 1 and 2.

[0083] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0084] 1...first conductor, 2...second conductor, 10, 20...uneven portion, 11, 21...recess, 11a...side portion of recess, 11b...bottom portion of recess, 12, 15, 22...protrusion, 13...tapered portion, 14...air layer, 100...insulating spacer, 101...first insulating spacer, 102...second insulating spacer, 200...adhesive.

Claims

1. A composite member comprising: a first conductor; a second conductor arranged at a predetermined interval from the first conductor and having a different potential from the first conductor; and an insulating spacer supporting the first conductor and the second conductor, A composite member characterized in that the insulating spacer has an uneven portion formed in a portion located between the first conductor and the second conductor, the uneven portion having a length that is 1 / 100 or more of the length along the surface of the insulating spacer, and an air layer is provided inside the insulating spacer and at least in the convex portion of the uneven portion.

2. 2. The composite member according to claim 1, a composite member, characterized in that the recesses of the concave-convex portion are formed in the insulating spacer on a first triple junction side where the insulating spacer, the first conductor, and the recesses of the concave-convex portion contact each other, and on a second triple junction side where the insulating spacer, the second conductor, and the recesses of the concave-convex portion contact each other.

3. 3. The composite member according to claim 2, A composite member characterized in that, between the first conductor and the second conductor, the creeping surface originating from the first and second triple junctions of the insulating spacer and the first and second conductors is horizontal in the vertical direction.

4. 4. The composite member according to claim 3, A composite member characterized in that the uneven portion is square.

5. A composite member according to any one of claims 1 to 4, A composite member characterized in that the insulating spacer comprises a first insulating spacer that is arranged inside and does not have the uneven portion, and a second insulating spacer that is arranged outside the first insulating spacer and has the uneven portion processed on its surface, and the first insulating spacer and the second insulating spacer are fixed with an adhesive.

6. A composite member comprising a first conductor, a second conductor arranged at a predetermined distance from the first conductor and having a different potential from the first conductor, and an insulating spacer supporting the first conductor and the second conductor, The insulating spacer has a concave-convex portion formed in a portion located between the first conductor and the second conductor, the concave-convex portion having a length equal to or greater than 1 / 100 of the length along the surface of the insulating spacer; A composite member characterized in that the insulating spacer comprises a first insulating spacer that is arranged inside and does not have the uneven portion, and a second insulating spacer that is arranged outside the first insulating spacer and has the uneven portion processed on its surface, and the first insulating spacer and the second insulating spacer are fixed with an adhesive.

7. 7. The composite member according to claim 6, a composite member, characterized in that the recesses of the concave-convex portion are formed in the insulating spacer on a first triple junction side where the insulating spacer, the first conductor, and the recesses of the concave-convex portion contact each other, and on a second triple junction side where the insulating spacer, the second conductor, and the recesses of the concave-convex portion contact each other.

8. 7. The composite member according to claim 6, a first triple junction side where the insulating spacer contacts the first conductor and the atmosphere, and a second triple junction side where the insulating spacer contacts the second conductor and the atmosphere, the protrusions of the concave-convex portion being formed on the insulating spacer.

9. 9. The composite member according to claim 8, A composite member, characterized in that the convex portions of the concave-convex portion are configured to be higher than the first triple point and the second triple point.

10. 7. The composite member according to claim 6, A composite member characterized in that a concave portion of the uneven portion that is lower than the first and second triple points is formed adjacent to each of a first triple point where the insulating spacer meets the first conductor and a concave portion of the uneven portion, and a second triple point where the insulating spacer meets the second conductor and a concave portion of the uneven portion, and a convex portion of the uneven portion that is higher than the first and second triple points is formed adjacent to each of the concave portions of the uneven portion.

11. 7. The composite member according to claim 6, a composite member characterized in that the insulating spacer is disposed between the first conductor and the second conductor, and convex portions of the uneven portion are formed on a first triple junction side where the first conductor, the insulating spacer, and the atmosphere come into contact, and on a second triple junction side where the second conductor, the insulating spacer, and the atmosphere come into contact, and concave portions of the uneven portion are formed adjacent to the convex portions and more inward of the insulating spacer than the first and second triple junctions.

12. 12. The composite member according to claim 11, a protrusion formed midway through the insulating spacer, the protrusion being higher than the protrusions formed on the first and second triple junction sides and higher than the first and second triple junctions.

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