Dispersion method of conductive particle

Abstract

To provide a dispersion method of conductive particles, with which the conductive particles can be separated from one another and two-dimensionally arranged on a base material, and with which variation of distances between the dispersed and arranged conductive particles is suppressed sufficiently.SOLUTION: A dispersion method of conductive particles includes a step to make blended particles P, located on an arrangement part 2 and consisting of intermediary particles to which the conductive particles with a particle size smaller than that of the intermediary particles are adhered, reciprocate between the arrangement part 2 and an adsorption part 5 so as to make the conductive particles adhered to the adsorption part 5 by forming an electric field between a first electrode 4 having the arrangement part 2 for arranging the particles and having static electricity diffusibility or conductivity and a second electrode 7 having an adsorption part 5 opposed to the arrangement part 2. The mass ratio of the conductive particles to the intermediary particles in the blended particles P is 1:500-1:1500.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for dispersing conductive particles. [Background technology]

[0002] Known methods for two-dimensionally arranging particles on a substrate include a dip coating method in which a substrate is immersed in a dispersion liquid in which spherical particles are dispersed, and the substrate is then pulled up and the dispersion medium is removed by drying, and an advection accumulation method (see, for example, Patent Document 1 below). These methods utilize the self-accumulation phenomenon of particles, and are suitable techniques for arranging particles in a closest-packed arrangement or for forming a particle film.

[0003] Meanwhile, the inventors have been developing a technique for arranging conductive particles two-dimensionally at intervals on a substrate, and have proposed a technique for dispersing and arranging conductive particles in the adsorption parts by using an electrostatic adsorption device having a specific adsorption part and compounded particles in which conductive particles are attached to intermediate particles (see, for example, Patent Document 2 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-223154 A [Patent Document 2] Patent Publication No. 2021-074707 Summary of the Invention [Problem to be solved by the invention]

[0005] The conductive particle dispersion method described in Patent Document 2 uses electrostatic repulsion between conductive particles to disperse the conductive particles in a dry process, and has the advantages of causing little damage to the conductive particles and not requiring a dispersion solvent, etc. Furthermore, if the variation in the interparticle distances of the dispersed conductive particles can be reduced, the practical advantages can be increased.

[0006] Therefore, an object of the present invention is to provide a method for dispersing conductive particles, which can arrange conductive particles two-dimensionally at a distance from one another on a substrate, and which can also sufficiently suppress variation in the interparticle distances of the dispersed conductive particles. [Means for solving the problem]

[0007] One aspect of the present invention relates to a method according to the following [1] to [6].

[0008] [1] A method for dispersing conductive particles, comprising the steps of: forming an electric field between a first electrode having a placement section that is electrostatically dissipative or conductive, and a second electrode having an adsorption section facing the placement section; thereby causing a blended particle, which is arranged in the placement section and has conductive particles that are smaller in particle size than the mediator particles attached to the mediator particles, to move back and forth between the placement section and the adsorption section, thereby adsorbing the conductive particles to the adsorption section; wherein the mass ratio of the conductive particles to the mediator particles in the blended particles is 1:500 to 1:1500. [2] A method for dispersing conductive particles, comprising a step of forming an electric field between a first electrode having a placement portion having electrostatic dissipation or conductivity, and a second electrode having an adsorption portion facing the placement portion, thereby causing a blended particle, which is arranged in the placement portion and has conductive particles having a particle size smaller than that of the mediator particles attached to the mediator particles, to move back and forth between the placement portion and the adsorption portion, thereby adsorbing the conductive particles to the adsorption portion, wherein the volume ratio of the conductive particles to the mediator particles in the blended particles is 1:900 to 1:2600. [3] A method for dispersing conductive particles, comprising a step of forming an electric field between a first electrode having a placement section that is electrostatically dissipative or conductive, and a second electrode having an adsorption section facing the placement section, thereby causing a blended particle, which is arranged in the placement section and has conductive particles that are smaller in particle size than the mediator particles attached to the mediator particles, to move back and forth between the placement section and the adsorption section, thereby adsorbing the conductive particles to the adsorption section, wherein the number ratio of the conductive particles to the mediator particles in the blended particles is 30:1 to 100:1. [4] The method for dispersing conductive particles according to any one of [1] to [3], wherein the placement section has a recess that opens toward the adsorption section, the recess has an inner wall surface that is tapered so that the opening width increases toward the adsorption section, and the compounded particles are placed in the recess. [5] The method for dispersing conductive particles according to any one of [1] to [4], further comprising a step of electrostatically adsorbing the conductive particles adsorbed on the adsorption section to a second adsorption section having insulating properties and arranged opposite the adsorption section. [6] The method for dispersing conductive particles according to any one of [1] to [5], wherein the medium particles are carbon particles having an average particle size of 100 to 150 μm. Effect of the Invention

[0009] According to the present invention, it is possible to provide a method for dispersing conductive particles, which can two-dimensionally arrange conductive particles on a substrate while spaced apart from one another, and which can also sufficiently suppress variation in the interparticle distances of the dispersed conductive particles, and an electrostatic adsorption device that can be used for said method. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic configuration of an electrostatic adsorption device used in a conductive particle dispersion method according to an embodiment of the present invention; [Diagram 2] FIG. 2(a) is a plan view showing a schematic diagram of an example of the suction portion, and FIG. 2(b) is a cross-sectional view taken along line Ib-Ib in FIG. 2(a). [Diagram 3] 10 is a cross-sectional view showing a schematic state in which conductive particles are accommodated in the opening of the adsorption part. FIG. [Figure 4] 13 is a plan view showing a schematic example of another opening pattern of the suction portion. FIG. [Diagram 5] 1 is a schematic diagram showing a particle blend used in a conductive particle dispersion method according to an embodiment of the present invention. FIG. [Figure 6] 1A to 1C are schematic diagrams for explaining a method for dispersing conductive particles according to one embodiment of the present invention. [Figure 7]5A to 5C are schematic diagrams for explaining another embodiment of the method for dispersing conductive particles. [Figure 8] 1A to 1C are schematic diagrams for explaining a method for dispersing conductive particles according to an embodiment of the present invention. [Figure 9] 1 is a diagram showing a schematic configuration of an electrostatic adsorption device used in a conductive particle dispersion method according to an embodiment of the present invention; [Figure 10] (a-1) to (d-1) of Figure 10 are plan views showing schematic examples of the arrangement section, (a-2) to (d-2) of Figure 10 are cross-sectional views taken along lines II to IV-IV of (a-1) to (d-1) of Figure 10, respectively, and (a-3) to (d-3) of Figure 10 are cross-sectional views showing other cross-sectional shapes of the arrangement section. [Figure 11] (e-1) to (f-1) of Figure 11 are plan views showing schematic examples of the placement section, (e-2) to (f-2) of Figure 11 are cross-sectional views taken along lines VV to VI-VI of (e-1) to (f-1) of Figure 11, respectively, and (e-3) to (f-3) of Figure 11 are cross-sectional views showing other cross-sectional shapes of the placement section. [Figure 12] (g-1) to (j-1) in Figure 12 are plan views showing schematic examples of the placement section, (g-2) to (j-2) in Figure 12 are cross-sectional views taken along lines VII-VII to XX in (g-1) to (j-1) in Figure 12, respectively, and (g-3) to (j-3) in Figure 12 are cross-sectional views showing other cross-sectional shapes of the placement section. [Figure 13] 1A to 1C are schematic diagrams for explaining a method for dispersing conductive particles according to an embodiment of the present invention. [Figure 14] FIG. 2 is a schematic diagram for explaining an example of an electrostatic adsorption device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as needed. However, the present invention is not limited to the following embodiment.

[0012] In the numerical ranges described in this specification in stages, the upper or lower limit of a certain numerical range may be replaced by the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced by a value shown in the examples. In this specification, for convenience, a collection of multiple conductive particles is also referred to as a "conductive particle". The same applies to mediating particles and blended particles.

[0013] [Dispersion method of conductive particles] The method for dispersing conductive particles in this embodiment includes a step of forming an electric field between a first electrode having a placement portion having electrostatic dissipation properties or conductivity, and a second electrode having an adsorption portion facing the placement portion, thereby causing a blended particle, which is arranged in the placement portion and has conductive particles with a particle size smaller than that of the mediator particles attached to the mediator particles, to move back and forth between the placement portion and the adsorption portion, thereby adsorbing the conductive particles to the adsorption portion.

[0014] The above method can include a step (hereinafter also referred to as the first step) of arranging mixed particles, in which conductive particles having a smaller particle size than the mediator particles are attached to the mediator particles, on the arrangement section of an electrostatic adsorption device that includes a first electrode having an arrangement section that is electrostatically dissipative or conductive for arranging particles, and a second electrode having an adsorption section facing the arrangement section, and a step (hereinafter also referred to as the second step) of forming an electric field between the first electrode and the second electrode to cause the mixed particles to move back and forth between the arrangement section and the adsorption section, thereby adsorbing the conductive particles to the adsorption section.

[0015] The adsorption portion may be an adsorption portion having electrostatic dissipation properties or electrical conductivity, or may be an adsorption portion having insulating properties.

[0016] The electrostatic dissipative placement portion and the electrostatic dissipative adsorption portion each have a surface resistivity of 10 13 It may be less than 10 6 The conductive arrangement portion and the conductive adhesion portion each may have a surface resistivity of 10 6 It may be less than 10 -3 The insulating adsorption portion may have a surface resistivity of 1013 It may be more than Ω.

[0017] 1 is a diagram showing a schematic configuration of an electrostatic adsorption device used in a conductive particle dispersion method according to this embodiment. The electrostatic adsorption device 1 includes a lower electrode (first electrode) 4 having an arrangement section 2 for arranging particles, an upper electrode (second electrode) 7 having an adsorption section 5 that is arranged above the arrangement section 2 in the direction of gravity and faces the arrangement section 2, a power source 8 connected to the lower electrode 4 and the upper electrode 7, and a control section 9 connected to the power source 8.

[0018] In the electrostatic adsorption device 1, the lower electrode 4 is composed of an electrode body 3 and a placement portion 2, and the upper electrode 7 is composed of an electrode body 6 and an adsorption portion 5. The lower electrode may be an integrated unit of the electrode body and the placement portion, and the upper electrode may be an integrated unit of the electrode body and the adsorption portion. In these cases, the surface of the lower electrode facing the upper electrode can be the placement portion, and the surface of the upper electrode facing the lower electrode can be the adsorption portion.

[0019] The material of the electrode body 3 constituting the lower electrode 4 can be one having electrostatic dissipation properties or electrical conductivity. For example, 13 Materials having a resistance of Ω or less can be used, and specific examples include metal, glass, etc. The shape of the electrode body 3 is not particularly limited, and may be, for example, a flat plate shape, a roll shape, or the like.

[0020] The material of the placement portion 2 may be one having electrostatic dissipation or conductivity. For example, 13 Materials having a resistance of Ω or less can be used, and specific examples include metal, glass, and conductive resin such as conductive polytetrafluoroethylene (PTFE). The shape of the placement part 2 is not particularly limited as long as it can place particles, and may be a membrane or film formed on the surface of the electrode body 3, or may have a shape capable of accommodating particles, for example, a shape having a bottom and side surfaces and opening toward the adsorption part. The placement part shown in FIG. 1 can accommodate a larger number of particles.

[0021] The lower electrode, in which the electrode body and the placement portion are integrated, is, for example, a metal or glass having a surface resistivity of 10 13 It is possible to use materials made of a resistance of Ω or less.

[0022] The electrode body 6 constituting the upper electrode 7 may be one having electrostatic dissipation properties or electrical conductivity. For example, 13 Materials having a resistance of Ω or less can be used, and specific examples thereof include metals and glass. The shape of the electrode body 6 is not particularly limited, and may be, for example, a flat plate or roll. When one of the electrode body 3 and the electrode body 6 is roll-shaped and the other is flat, the electrodes 4 and 7 may be configured so that the rotation axis of the roll and the main surface of the flat plate are parallel to each other, and the suction portion and the placement portion face each other at a predetermined distance on the line connecting the rotation axis and the main surface at the shortest distance. When both the electrode body 3 and the electrode body 6 are roll-shaped, the electrodes 4 and 7 may be configured so that the rotation axes of both rolls are parallel to each other, and the suction portion and the placement portion face each other at a predetermined distance on the line connecting the rotation axes at the shortest distance.

[0023] The material of the adsorption part 5 may be one having electrostatic dissipation or conductivity. For example, 13 Materials having a resistance of Ω or less can be used, and specific examples thereof include metal, glass, and conductive resin such as conductive PTFE. The shape of the adsorption portion 5 is not particularly limited, and may be a membrane or film formed on the surface of the electrode body 6.

[0024] The upper electrode, in which the electrode body and the adsorption portion are integrated, is made of, for example, metal, glass, etc., with a surface resistivity of 10 13 It is possible to use materials made of a resistance of Ω or less.

[0025] The adsorption part 5 may be provided with an opening pattern (multiple openings) that open to the placement part side. The shape of such adsorption part 5 may be a membrane or film formed on the surface of the electrode body 6, or a film that can be separated from the electrode body 6.

[0026] Fig. 2(a) is a plan view showing a schematic example of the suction part, and Fig. 2(b) is a cross-sectional view taken along line Ib-Ib in Fig. 2(a). The suction part 5 shown in Fig. 2(a) is provided with a plurality of openings (recesses) 72 having a predetermined pattern (opening pattern). The predetermined pattern (opening pattern) may be arranged regularly.

[0027] The opening 72 of the adsorption part 5 is preferably formed in a tapered shape in which the opening area increases from the bottom 72a side of the opening 72 toward the surface 5a side of the adsorption part 5. That is, as shown in Figures 2(a) and 2(b), the width of the bottom 72a of the opening 72 (width a in Figures 2(a) and 2(b)) is preferably narrower than the width of the opening at the surface 5a of the opening 72 (width b in Figures 2(a) and 2(b)). The size of the opening 72 (width a, width b, volume, taper angle, depth, etc.) may be set according to the size of the conductive particles to be accommodated.

[0028] For example, the width b of the opening may be 1.0 to 1.5 times, or 1.05 to 1.45 times, the particle size of the conductive particles, and the particle size of the mediating particles may be 2.0 to 110 times, or 2.5 to 100 times, the width b of the opening.

[0029] The shape of the opening 72 may be a shape other than the shapes shown in Figures 2(a) and 2(b). For example, the shape of the opening on the surface 5a may be an ellipse, a triangle, a rectangle, a polygon, etc., other than the circle shown in Figure 2(a). The bottom 72a may also be a shape other than a flat surface, such as a mountain shape, a valley shape, or a collection of fine protrusions.

[0030] 3 is a cross-sectional view showing a state where conductive particles are accommodated in the opening of the adsorption part. From the viewpoint of removing particles (excess particles) other than the conductive particles accommodated in the opening and facilitating the transfer of the accommodated conductive particles to an adhesive substrate, the shape of the opening 72 can be set so that the distance X between the apex of the conductive particle accommodated in the opening 72 on the opposite side to the adsorption part and the surface 5a of the adsorption part is -20 to 80%, preferably -15 to 60%, of the particle diameter d of the conductive particle. Note that when X is a positive value, it means that the conductive particle protrudes from the surface 5a of the adsorption part as shown in FIG. 3, and when X is a negative value, it means that the conductive particle does not protrude from the surface 5a of the adsorption part, in other words, is buried.

[0031] The material constituting the adsorption part 5 having the opening pattern can be, for example, inorganic materials such as silicon, various ceramics, glass, metals such as stainless steel, and organic materials such as various resins. The openings 72 of the adsorption part can be formed by known methods such as photolithography and nanoimprinting. The adsorption part may be a single layer, or may be composed of multiple layers such as a laminate of a base layer and an opening layer having openings. When the adsorption part is a laminate, it may be, for example, a film having an opening layer formed by a method such as photolithography or nanoimprinting using a photocurable resin composition on a base layer such as PET. The static electricity diffusion or conductivity of the adsorption part can be adjusted by the type of material constituting it, surface treatment, etc.

[0032] The adsorption portion 5 on which the opening pattern is provided may be an insulating adsorption portion.

[0033] The opening pattern can be appropriately set so that the conductive particles can be dispersed in a desired arrangement. In the adsorption portion 5 shown in Fig. 2(a), the round hole openings are arranged in series in a lattice pattern, but they can also be staggered at 60° as shown in Fig. 4. The opening pattern may be such that the openings are arranged in an orderly fashion or randomly.

[0034] In the electrostatic adsorption device 1, the lower electrode 4 and the upper electrode 7 are arranged with a predetermined gap therebetween, and the distance between the electrodes can be 0.1 to 500 mm, optionally 0.5 to 100 mm, optionally 1 to 20 mm, or optionally 2 to 15 mm.

[0035] In the electrostatic adsorption device 1, the lower electrode 4 may be movable, in which case it is easy to continuously supply the blended particles. For example, the lower electrode may be provided on the surface of a belt or a cylindrical roller.

[0036] In the electrostatic attraction device 1, the upper electrode 7 may be movable, in which case it becomes easy to continuously supply the attraction parts that attract the conductive particles. For example, the upper electrode can be provided on the surface of a belt or a cylindrical roller.

[0037] The power supply 8 may be any power supply capable of forming an electric field between the lower electrode and the upper electrode, and may be, for example, a known high-voltage power supply. The high-voltage power supply may be a DC power supply or an AC power supply.

[0038] The control unit 9 can have functions such as adjusting the voltage to be applied and the application time.

[0039] <1st process> In the first step, a mixture of particles, each of which is a mediator particle to which conductive particles having a particle size smaller than that of the mediator particle are attached, is placed (contained) in the placement section 2 of the electrostatic adsorption device 1. Fig. 5 is a schematic diagram showing a mixture of particles. As shown in Fig. 5, the mixture of particles P is composed of a mediator particle 10 and conductive particles 12 attached to the surface of the mediator particle.

[0040] The mediating particles 10 may be particles having electrostatic dissipation or conductivity, and have a surface resistivity of 10 13Particles containing a material having a resistance of Ω or less can be used. For example, carbon particles, metal particles such as solder, glass particles, and inorganic particles having static electricity dissipation properties can be used. These can be used alone or in combination of two or more.

[0041] The mediating particle 10 may be spherical or approximately spherical, and may have recesses, protrusions, or both recesses and protrusions on its surface.

[0042] The particle size of the intermediate particle 10 may be 30 to 500 μm, 40 to 400 μm, 50 to 300 μm, 70 to 200 μm, or 100 to 150 μm, from the viewpoint of preventing the aggregation of the mixed particles while facilitating the movement of the mixed particles. From the viewpoint of the handleability of the intermediate particle, the intermediate particle 10 may include spherical particles having a diameter of 60 to 250 μm, spherical particles having a diameter of 70 to 250 μm, spherical particles having a diameter of 80 to 149 μm, or spherical particles having a diameter of 106 to 149 μm.

[0043] The mediating particles 10 may contain no more than 50 mass % of particles with a particle size of less than 106 μm, or may contain no particles with a particle size of less than 106 μm.

[0044] The difference between the maximum particle size and the minimum particle size of the medium particles 10 may be 200 μm or less, 100 μm or less, or 50 μm or less.

[0045] The specific gravity of the medium particles 10 is 1.0 to 2.0 g / cm 3 , 2.1~3.0g / cm 3 , or 3.1 to 5.0 g / cm 3 From the viewpoint of facilitating the electrostatic adsorption of the particles, the mediator particle 10 may have a specific gravity of 2.0 to 2.5 g / cm 3 , or 1.4 to 1.5 g / cm 3 The particle may be one in which

[0046] In this embodiment, the intermediate particles may have an average particle size of 30 to 500 μm, 40 to 400 μm, 50 to 300 μm, 70 to 200 μm, or 100 to 150 μm. In this specification, the average particle size of the particles means the median diameter (D50). The median diameter (D50) of the particles can be measured using a particle size distribution measuring device (for example, a device named "MT3000II" manufactured by Microtrack Bell Co., Ltd.).

[0047] The CV value of the particle diameter of the intermediate particle 10 may be 50% or less, 40% or less, or 30% or less. In this specification, the CV value of the particle diameter is a value calculated by dividing the standard deviation of the particle diameter by the average particle diameter and multiplying the result by 100, and is a parameter that indicates the degree of variation in the particle diameter.

[0048] In addition, the intermediate particle 10 may be selected by placing it in the placement section of the electrostatic adsorption device in which the second step is performed, and confirming that it moves back and forth between the lower electrode (first electrode) and the upper electrode (second electrode) when an electric field is applied under the specified conditions described below.

[0049] The conductive particles 12 may be any material that contains a conductive material and functions as a conductive material, and examples of such materials include metal particles such as gold, silver, nickel, copper, and solder, and conductive coated particles in which non-conductive particles such as carbon particles, glass, ceramic, and plastic are coated with a conductive material such as metal. Metals that coat non-conductive particles include gold, silver, nickel, copper, and solder, and may have a multilayer structure. The conductive particles may have an insulating coating (e.g., insulating fine particles) on at least a part of the outer surface of the conductive particles.

[0050] The conductive particles may be used alone or in combination of two or more kinds.

[0051] The conductive particles 12 may be spherical or approximately spherical, or may be composite particles comprising a conductive particle and a plurality of insulating fine particles provided on at least a portion of the outer surface of the conductive particle.

[0052] The particle size of the conductive particles 12 may be 1 to 40 μm, 1.5 to 30 μm, 2 to 20 μm, 1 to 10 μm, or 2 to 5 μm.

[0053] The specific gravity of the conductive particles 12 is 1.0 to 5.0 g / cm 3 , 1.2~4.5g / cm 3 , or 1.4 to 4.0 g / cm 3 From the viewpoint of facilitating the electrostatic adsorption of the particles, the mediator particle 10 may have a specific gravity of 3.1 to 4.0 g / cm 3 , or 2.0 to 3.0 g / cm 3 The particle may be one in which

[0054] In this embodiment, conductive particles having an average particle size of 1 to 40 μm, 1.5 to 30 μm, 2 to 20 μm, 1 to 10 μm, or 2 to 5 μm may be used.

[0055] The conductive particles 12 may have a CV value of the particle diameter of 30% or less, 25% or less, or 20% or less.

[0056] The particle size of the intermediate particle constituting the blended particle P may be 5 to 200 times, 10 to 150 times, 10 to 100 times, or 30 to 50 times the particle size of the conductive particle, from the viewpoint of efficiently adsorbing the conductive particle to the adsorption portion.

[0057] From the viewpoint of increasing the particle density of the dispersed conductive particles while sufficiently suppressing the variation in particle density, the ratio [D1 / D2] of the average particle size D1 of the conductive particles to the average particle size D2 of the intermediate particles may be greater than 0.017 and less than 0.031, may be 0.017 or more and 0.031 or less, or may be 0.020 or more and 0.027 or less.

[0058] The blended particles P can be prepared by mixing the mediator particles and the conductive particles. The mixing method is not particularly limited, but for example, a known mixing means such as a stirrer may be used, or a container containing the mediator particles and the conductive particles may be shaken. Mixing is preferably performed to the extent that the particles are not damaged.

[0059] The mixing ratio of the mediator particles and the conductive particles can be appropriately set so that the conductive particles are sufficiently attached to the surfaces of the mediator particles. Note that if the amount of the conductive particles is too large, the conductive particles are likely to aggregate, so it is preferable to set the mixing ratio within a range that can suppress the aggregation of the conductive particles.

[0060] In this embodiment, in order to suppress variation in the interparticle distance of the dispersed conductive particles, the blended particles P may satisfy at least one of the following conditions (a), (b), and (c). (a) The mass ratio of conductive particles to mediator particles (hereinafter sometimes referred to as "RW") in the mixed particles is 1:500 to 1:1500. (b) The volume ratio of conductive particles to mediator particles in the mixed particles (hereinafter sometimes referred to as "RV") is 1:900 to 1:2600. (c) The ratio of the number of conductive particles to the number of mediator particles (hereinafter sometimes referred to as "RC") in the mixed particles is 30:1 to 100:1.

[0061] From the viewpoint of increasing the particle density of the dispersed conductive particles while suppressing the variation in the interparticle distance, RW may be 1:500 to 1:1300, 1:500 to 1:1100, 1:500 to 1:900, or 1:700 to 1:900. When preparing the blended particles P, the conductive particles and the mediating particles can be blended in the above mass ratio.

[0062] From the viewpoint of suppressing variation in the interparticle distance while increasing the particle density of the dispersed conductive particles, the RV may be 1:900 to 1:2300, 1:900 to 1:2000, 1:900 to 1:1600, or 1:1200 to 1:1500. When preparing the blended particles P, the conductive particles and the mediating particles can be blended in the above volume ratio.

[0063] From the viewpoint of increasing the particle density of the dispersed conductive particles while suppressing variation in the interparticle distance, RC may be 35:1 to 100:1, 40:1 to 100:1, 50:1 to 100:1, or 50:1 to 70:1. When preparing the blended particles P, the conductive particles and the mediator particles can be blended in the above volume ratio.

[0064] <Second process> In the second step, an electric field is formed between the first electrode and the second electrode, and the mixed particles are caused to reciprocate between the placement section and the adsorption section, thereby causing the conductive particles to be adsorbed to the adsorption section.

[0065] FIG. 6 is a diagram for explaining the second step, and FIG. 6(a) shows the reciprocating motion (up and down motion) of the mixed particles when the adsorption part has electrostatic dissipation or conductivity and an electric field is applied between the lower electrode (first electrode) and the upper electrode (second electrode). The mixed particles, which are charged with the opposite polarity to the upper electrode in the arrangement part, rise due to electrostatic attraction. The risen mixed particles come into contact with the adsorption part. At this time, the small conductive particles attached to the surface of the large mediator particle are adsorbed to the adsorption part. The mixed particles that come into contact with the adsorption part are charged with the same polarity as the upper electrode and fall due to electrostatic repulsion and, in this embodiment, gravity. The descending mixed particles are charged with the opposite polarity to the upper electrode in the arrangement part and rise due to electrostatic attraction. By repeating these steps, the conductive particles are adsorbed to the adsorption part. In addition, by adhering the conductive particles to the surface of the mediator particle, it is possible to suppress the conductive particles from agglomerating with each other, and the conductive particles adsorbed to the adsorption part are arranged so that the particles are spaced apart from each other. In this way, as shown in FIG. 6(b), the upper electrode 7 having the conductive particles 12 adsorbed to the adsorption portion 5, that is, the electrode 20 with conductive particles, is obtained.

[0066] When the adsorption section is insulating, the adsorption section is positioned above the placement section in the direction of gravity, and the mixed particles move to the second electrode due to electrostatic attraction caused by the mixed particles being charged with the opposite polarity to the second electrode, and the mixed particles that come into contact with the adsorption section release the conductive particles, losing their charge, and moving to the first electrode due to their own weight.This allows the small conductive particles attached to the surface of the large intermediate particles to be adsorbed to the adsorption section by repeating this process.

[0067] The distance between the first electrode and the second electrode may be 0.1 to 500 mm, 0.5 to 400 mm, 1 to 200 mm, 1 to 50 mm, or 1 to 20 mm. The shorter the distance between the electrodes, the smaller the number of conductive particles that are adsorbed, but the number of conductive particles that are adsorbed at the second adsorption part can be increased in the third step described below. This is because the shorter the distance between the electrodes during the up and down movement, the shorter the distance over which the mixed particles are accelerated, so the number of particles that adhere to the adsorption part of the second electrode decreases, and the speed of the mixed particles just before they collide with the adsorption part of the second electrode slows, so that the conductive particles adhere to the adsorption part of the second electrode with a weaker force, making it easier for them to fly up to the third electrode.

[0068] The intensity of the electric field to be applied can be 0.1 to 30 kV / cm, may be 0.5 to 30 kV / cm, or may be 1 to 20 kV / cm.

[0069] The application of the electric field may be continuous or intermittent.

[0070] The application time of the electric field can be appropriately set depending on the amount of conductive particles to be adsorbed to the adsorption portion.

[0071] When the second electrode is a roll-shaped roller electrode, the rotation speed can be set to a peripheral speed of 1 to 100 mm / sec, and may be set to, for example, 23.5 mm / sec, 47 mm / sec, or 94 mm / sec, etc. Note that the slower the rotation speed, the greater the number of conductive particles that are adsorbed tends to be.

[0072] The electrode 20 with conductive particles obtained through the second step may be used as it is as a substrate on which the conductive particles are spaced apart and arranged two-dimensionally, or may be used to transfer the conductive particles onto a specified substrate.

[0073] Fig. 7 is a diagram showing the second step when the adsorption part 5 has an opening pattern. In this case, by performing the second step in the same manner as described above, an upper electrode 7 in which conductive particles 12 are accommodated in the openings 72 of the adsorption part 5, i.e., an electrode 20 with conductive particles, is obtained as shown in Fig. 7(b).

[0074] The dispersion method according to the present embodiment in which the adsorption section 5 has an opening pattern may further include a step of removing particles (surplus particles) other than the conductive particles contained in the openings that are attached to the adsorption section (hereinafter also referred to as a surplus particle removing step). The surplus particle removing step can be performed before the conductive particles contained in the openings are transferred onto a predetermined adhesive substrate. In this case, the particles removed from the adsorption section may be collected and recycled, and it is preferable to collect and recycle at least the conductive particles among the surplus particles.

[0075] Methods for removing excess particles include physical removal means such as air blowing, brushing, and squeegees, and electrostatic removal means such as ionizers.

[0076] The conductive particle dispersion method of this embodiment may further include a step (hereinafter also referred to as a third step) of electrostatically adsorbing the conductive particles adsorbed to the adsorption portion to a second adsorption portion having insulating properties and arranged opposite the adsorption portion.

[0077] <3rd process> 8 is a diagram for explaining the third step, and an electrostatic attraction device 1' shown in Fig. 8 has the same configuration as the electrostatic attraction device 1, except that the lower electrode 4 in the electrostatic attraction device 1 is replaced with an electrode 20 with conductive particles obtained through the second step, and the upper electrode 7 is replaced with a third electrode 24 having an insulating second attraction portion 22 arranged so as to face the attraction portion 5 of the electrode 20 with conductive particles. In Fig. 8, 8' and 9' respectively denote a power source and a control portion.

[0078] The third electrode 24 is composed of an electrode body 23 and a second adsorption portion 22.

[0079] The electrode body 23 constituting the third electrode 24 may be one having electrostatic dissipation or conductivity. For example, 13 Materials having a resistance of Ω or less can be used, and specific examples include metal, glass, etc. The shape of the electrode body 23 is not particularly limited, but may be, for example, a flat plate shape, a roll shape, or the like.

[0080] The second adsorption portion 22 may be made of an insulating material. For example, a material having a surface resistivity of 10 13 A material having a resistance of more than Ω can be used, and specifically, a resin such as polytetrafluoroethylene can be used. The shape of the second adsorption portion 22 is not particularly limited, and may be a membrane or film formed on the surface of the electrode body 23, or may be a film that can be separated from the electrode body 23.

[0081] The second adsorption portion 22 may have a surface on the adsorption portion 5 side of the conductive particle-attached electrode 20 that has electrostatic dissipation properties or conductivity. Such a second adsorption portion 22 may be a layer formed from the above-mentioned insulating material to which a layer having electrostatic dissipation properties or conductivity has been provided, or a layer formed from the above-mentioned insulating material to which a surface treatment has been applied to impart electrostatic dissipation properties or conductivity.

[0082] By forming an electric field between the electrode 20 with conductive particles and the third electrode 24 of the electrostatic adsorption device 1', the conductive particles of the electrode 20 with conductive particles are charged with a polarity opposite to that of the third electrode 24, and rise due to electrostatic charge and are adsorbed to the adsorption portion 22, which is the second adsorption portion. As a result, the adsorption portion 22 to which the conductive particles 12 are adsorbed is obtained.

[0083] By providing the third step, it becomes easier to adjust the particle density and to make the distances between the conductive particles more uniform.

[0084] In addition, the electrostatic adsorption of the conductive particles can be stopped when a predetermined amount of conductive particles are adsorbed to the second adsorption part due to the reduction of the electric field caused by the conductive particles being adsorbed to the insulating second adsorption part, and the above effect can be easily obtained. That is, the strength of the electric field between the electrode 20 with conductive particles and the third electrode 24 becomes smaller as the conductive particles are attached to the second adsorption part. Therefore, in addition to the conductive particles disappearing from the surface of the electrode with conductive particles, the flying of the conductive particles can be stopped by making the electric field between the electrodes sufficiently small. By utilizing this phenomenon, for example, by making the electrode with conductive particles movable so that a sufficient amount of conductive particles can be supplied, the conductive particles can be adsorbed to the adsorption part of the third electrode until the electric field becomes sufficiently weak. At this time, it is considered that all the conductive particles are charged with the same polarity, and even if the conductive particles fly to the same place as the conductive particles already adsorbed, the conductive particles move to avoid collision due to electrostatic repulsion, and can be adsorbed to a place where the conductive particles are not adsorbed. Therefore, by providing the third process, it is expected that a sufficient number of conductive particles can be attached to the adsorption portion while maintaining approximately equal spacing between the particles, i.e., achieving both a high level of conductive particle density and uniform dispersion.

[0085] The distance between the electrode 20 and the third electrode 24 may be 0.1 to 500 mm, 0.5 to 400 mm, 1 to 200 mm, 0.5 to 10 mm, or 0.5 to 5 mm.

[0086] The intensity of the electric field to be applied can be 0.1 to 100 kV / cm, may be 0.2 to 90 kV / cm, or may be 0.3 to 80 kV / cm.

[0087] The application of the electric field may be continuous or intermittent.

[0088] The application time of the electric field can be appropriately set depending on the amount of conductive particles to be adsorbed to the adsorption portion.

[0089] The second suction portion 22 may be provided with an opening pattern (multiple openings) that open to the placement portion side. The shape of such suction portion 22 may be a membrane or film formed on the surface of the electrode body 23, or a film that can be separated from the electrode body 23.

[0090] The second adsorption portion 22 having an opening pattern can be designed in the same manner as the above-mentioned adsorption portion 5 having an opening pattern, except that it is insulating. In the second adsorption portion 22 having an opening pattern, the surface of the conductive particle-attached electrode 20 on the adsorption portion 5 side may also have electrostatic dissipation properties or conductivity.

[0091] In addition, the above-mentioned excess particle removal step can be carried out.

[0092] In the electrostatic attraction device 1', the third electrode 24 may be movable, in which case it is easy to continuously supply the attraction parts that attract the conductive particles. For example, the third electrode may be provided on the surface of a belt or a cylindrical roller. Also, the second attraction part may be a film that is continuously supplied.

[0093] In the electrostatic adsorption device described above, the first electrode, the second electrode, the electrode with conductive particles, and the third electrode are arranged on the lower side and the upper side, respectively, with respect to the direction of gravity, but in the conductive particle dispersion method of this embodiment, the moving direction of the mixed particles or the conductive particles may be horizontal or inclined with respect to the direction of gravity. Even in these cases, the first electrode, the second electrode, and the third electrode may have the same configuration as described above. Furthermore, the first step, the second step, and the third step may be performed consecutively.

[0094] In addition, in the first dispersion method of conductive particles of this embodiment, the placement section has a recess that opens toward the adsorption section, and the recess has an inner wall surface that is tapered so that the opening width increases toward the adsorption section, and the compounded particles may be placed in the recess.

[0095] According to the above method, since the placement part has the above-mentioned recess, the adhesion density of the conductive particles adsorbed to the adsorption part can be increased, and the efficiency of the dispersion and placement of the conductive particles can be improved. The inventors speculate as follows about the reason why the adhesion density of the conductive particles is increased. It is considered that the placement part of the first electrode has a recess having the above-mentioned inner wall surface, so that the equipotential surface has an equipotential distribution that is concavely curved near the recess, and the electrostatic force tends to gather at the center of the recess. This prevents the mixed particles from scattering outside the recess during the up and down movement, and the number of mixed particles that can be reciprocated per unit time and unit area is increased, which is thought to have achieved the above effect.

[0096] Fig. 9 is a diagram showing a schematic configuration of an electrostatic attraction device used in the conductive particle dispersion method according to the above embodiment. The electrostatic attraction device 1 shown in Fig. 9 has the same configuration as the electrostatic attraction device 1 shown in Fig. 1, except that it includes a placement unit 2 having a recess 30 that opens to the attraction unit 5 side.

[0097] The recess 30 has an inner wall surface S1 that is tapered so that the opening width increases toward the adsorption portion 5. The arrangement portion shown in Fig. 9 has a flat portion S0 and a hemispherical recess 30, and the blended particles P can be arranged in the recess 30. The recess may have another shape, may be provided in multiple numbers, or may be provided in a predetermined pattern.

[0098] The shape of the recess may be, for example, a hemisphere, an inverted cone, an inverted truncated cone, an inverted polygonal truncated shape such as an inverted triangular pyramid or an inverted square truncated shape, an inverted polygonal truncated shape such as an inverted square truncated shape, or a valley shape having a V-shaped, U-shaped or inverted trapezoidal cross section, etc. When the recess is valley-shaped, the opening width of the recess means the width of the valley.

[0099] The inner wall surface of the recess may be tapered so that the opening area increases from the bottom of the recess toward the suction portion.

[0100] The tapered inner wall surface may be a part of or the entire inner wall of the recess. The recess may have a wall surface that does not increase the opening width.

[0101] The tapered inner wall surface may be stepped or may have roughness.

[0102] 10 to 12 are diagrams showing examples of arrangement parts provided with recesses. The arrangement part 2a shown in (a-1) to (a-3) of FIG. 10 is provided with a semispherical recess 30a. As shown in (a-3) of FIG. 10, the side of the arrangement part 2a opposite to the side where the recess is provided may be flat. The arrangement part 2b shown in (b-1) to (b-3) of FIG. 10 is provided with a recess 30b in the shape of an inverted truncated cone having a flat bottom surface S2. As shown in (b-3) of FIG. 10, the side of the arrangement part 2b opposite to the side where the recess is provided may be flat. The arrangement part 2c shown in (c-1) to (c-3) of FIG. 10 is provided with a recess 30c in the shape of an inverted pyramid. As shown in (c-3) of FIG. 10, the side of the arrangement part 2c opposite to the side where the recess is provided may be flat. The arrangement portion 2d shown in Fig. 10(d-1) to (d-3) is provided with a recess 30d having an inverted truncated pyramid shape with a flat bottom surface S2. As shown in Fig. 10(d-3), the surface of the arrangement portion 2d opposite to the side where the recess is provided may be flat.

[0103] The arrangement portion 2e shown in (e-1) to (e-3) of FIG. 11 is provided with a U-shaped valley-shaped recess 30e extending in one direction. As shown in (e-3) of FIG. 11, the side of the arrangement portion 2e opposite to the side where the recess is provided may be flat. The arrangement portion 2f shown in (f-1) to (f-3) of FIG. 11 is provided with a V-shaped valley-shaped recess 30f extending in one direction. As shown in (f-3) of FIG. 11, the side of the arrangement portion 2f opposite to the side where the recess is provided may be flat.

[0104] The arrangement portion 2g shown in (g-1) to (g-2) of FIG. 12 has a plurality of inverted rectangular prism-shaped recesses 30g arranged in a lattice pattern. The arrangement portion 2g has flat portions between the recesses 30g. The arrangement portion 2h shown in (h-1) to (h-2) of FIG. 12 has a plurality of U-shaped valley-shaped recesses 30h arranged side by side. The arrangement portion 2h has flat portions between the recesses 30h. The arrangement portion 2i shown in (i-1) to (i-2) of FIG. 12 has a plurality of inverted rectangular prism-shaped recesses 30i arranged in a predetermined pattern. The arrangement portion 2j shown in (j-1) to (j-2) of FIG. 12 has a plurality of U-shaped valley-shaped recesses 30j arranged side by side.

[0105] The size of the recess (width, opening area, volume, taper angle and depth of the inner wall surface, etc.) may be appropriately set according to the amount of blended particles to be placed. For example, when the recess is hemispherical, inverted conical, or inverted truncated conical, the maximum diameter of the opening may be 2 to 200 mm, the maximum depth may be 0.1 to 100 mm, and the maximum diameter / maximum depth may be 0.02 to 2000. When the recess is inverted polygonal prism or inverted polygonal truncated prism, the maximum width of the opening may be 2 to 200 mm, the maximum depth may be 0.1 to 100 mm, and the maximum width / maximum depth may be 0.02 to 2000. When the recess is in the shape of a valley, the maximum width of the valley may be 2 to 200 mm, the maximum depth may be 0.1 to 100 mm, and the maximum width / maximum depth may be 0.02 to 2000.

[0106] The lower electrode, in which the electrode body and the placement portion are integrated, is, for example, a metal or glass having a surface resistivity of 1×10 13 It is possible to use materials made of a resistance of Ω or less.

[0107] FIG. 13 is a diagram for explaining the second step performed by an electrostatic adsorption device having a placement section with a recess. FIG. 13(a) shows the reciprocating motion (up and down motion) of the mixed particles when an electric field is applied between the lower electrode (first electrode) and the upper electrode (second electrode). The mixed particles charged with the polarity opposite to that of the upper electrode in the placement section rise due to electrostatic attraction. The rising mixed particles come into contact with the adsorption section. At this time, the conductive particles with a small particle size attached to the surface of the intermediate particles with a large particle size are adsorbed to the adsorption section. When the adsorption section has electrostatic dissipation or conductivity, the mixed particles that come into contact with the adsorption section are charged with the same polarity as the upper electrode and fall due to electrostatic repulsion and, in this embodiment, gravity. When the adsorption section has insulating properties, the mixed particles that come into contact with the adsorption section lose their charge as the conductive particles move to the adsorption section, and in this embodiment, they fall due to gravity. The descending mixed particles are charged with the polarity opposite to that of the upper electrode in the placement section and rise due to electrostatic attraction. By repeating these steps, the conductive particles are adsorbed to the adsorption section. In addition, by attaching the conductive particles to the surface of the mediator particle, the conductive particles can be prevented from agglomerating, and the conductive particles adsorbed to the adsorption portion are arranged so that the particles are spaced apart from each other. In addition, in this embodiment, since the arrangement portion has the above-mentioned recess, the adhesion density of the conductive particles adsorbed to the adsorption portion can be increased, and the efficiency of the dispersion and arrangement of the conductive particles can be improved. In this way, as shown in Figure 13 (b), an upper electrode 7 in which the conductive particles 12 are adsorbed to the adsorption portion 5, i.e., an electrode 20 with conductive particles, is obtained.

[0108] FIG. 14 is a diagram showing an example of an electrostatic adsorption device. This electrostatic adsorption device has an arrangement portion 2g in which a plurality of inverted rectangular prism-shaped recesses 30g shown in (g-1) and (g-2) of FIG. 4 are arranged in a lattice pattern as a first electrode, and a cylindrical roller electrode 40 as a second electrode in which the electrode body and the adsorption portion are integrated, and the arrangement portion 2g can move horizontally in the direction of arrow B (or other direction), and the roller electrode 40 can rotate in the direction of arrow A (or the opposite direction). Alternatively, the arrangement portion 2g may be fixed, and the adsorption portion 5a may rotate or move horizontally. Furthermore, the electrostatic adsorption device shown in FIG. 14 includes a cylindrical roller electrode 50 having a second adsorption portion 22a provided on its surface. The roller electrode 50 can rotate in the direction of arrow C (or the opposite direction). The roller electrodes 40 and 50 are arranged such that their rotation axes are parallel to each other and the surface of the roller electrode 40 and the second adsorption portion face each other at a predetermined distance on the line connecting the rotation axes at the shortest distance.

[0109] The electrostatic adsorption device shown in FIG. 14 can perform the above-mentioned first, second and third steps.

[0110] According to the conductive particle dispersion method of this embodiment, the conductive particles can be spaced apart and arranged two-dimensionally, and therefore the method can be applied to various electronic materials such as conductive materials. EXAMPLES

[0111] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0112] <Average particle size> The average particle size of the particles shown below is the median diameter (D50) measured using a particle size distribution measuring device (manufactured by Microtrack Bell Co., Ltd., device name "MT3000II").

[0113] [Preparation of carrier particles] (Mediator particle 1) Spherical carbon particles (manufactured by Nippon Carbon Co., Ltd., product name "ICB-15020") were classified using a sieve with a mesh size of 106 μm (140 mesh) and a sieve with a mesh size of 150 μm (100 mesh) to prepare intermediate particle 1 containing spherical carbon particles with a diameter of 106 μm or more and less than 150 μm. The average particle size (D50) of intermediate particle 1 was 130 μm. The CV value of the particle size of intermediate particle 1 was 21%.

[0114] [Preparation of compounded particles] (Preparation Example 1) 800 parts by mass of the mediator particle 1 and 1 part by mass of conductive coated particles with an average particle size of 3 μm (CV value of particle size is 6.6%), which are made by plating the surface of a plastic core particle with a diameter of 2.5 μm with Ni, were placed in a glass container, and the container was shaken to mix, thereby obtaining compounded particle 1. The obtained compounded particle 1 was observed with a scanning electron microscope, and it was confirmed that the conductive particles were attached to the surface of the mediator particle.

[0115] (Preparation Example 2) Blended particles 2 were obtained in the same manner as in Preparation Example 1, except that the blending ratio of the mediator particles 1 was changed to 1,000 parts by mass per 1 part by mass of the conductive coated particles.

[0116] (Preparation Example 3) Blended particles 3 were obtained in the same manner as in Preparation Example 1, except that the blending ratio of the mediator particles 1 was changed to 1200 parts by mass per 1 part by mass of the conductive coated particles.

[0117] The volume ratio RV and number ratio RC calculated using the average particle diameter and specific gravity for the above preparation examples are summarized in Table 1. The specific gravity of the intermediate particle 1 is 1.43 g / cm 3 The specific gravity of the electrocoated particles is 2.48 g / cm 3 It is.

[0118] [Table 1]

[0119] [Dispersion of conductive particles] Example 1 An apparatus having the same configuration as the electrostatic chucking apparatus shown in Fig. 14 was prepared. In this apparatus, a copper plate (depth 10 cm x width 10 cm x thickness 5 mm) (S electrode) having a hemispherical recess 30a with a diameter of 15 mm and a maximum depth of 2 mm was used as the first electrode, a rotating cylindrical electrode (D electrode) with an outer diameter of 90 mm was used as the second electrode, and a rotating cylindrical electrode (C electrode) with an outer diameter of 90 mm covered with an insulating sheet (PET film with a thickness of 6 mm) was used as the third electrode, with the distance between the C electrode and the D electrode being 7 mm, and the distance between the S electrode and the D electrode being d DS is 9 mm, and the distance d between the insulating sheet and the D electrode is CD The electrodes were positioned so that the distance between the electrodes was 1 mm.

[0120] 10 mg of the compounded particles 1 obtained in Preparation Example 1 was placed in the recess of the copper plate (S electrode), and a negative voltage of -1.3 kV was applied to the S electrode while rotating the D electrode at a peripheral speed of 2 mm / s, causing the compounded particles P to move up and down (reciprocating motion) between the S electrode and the D electrode. Next, a positive voltage of 3 kV was applied to the C electrode, causing the conductive particles adsorbed on the D electrode to fly up and adsorb (electrostatic adsorption) onto the insulating sheet.

[0121] The adsorption surface of the insulating sheet is imaged and the number of particles within the screen (actual scale: 0.5 mm x 0.5 mm) is counted, and the number of conductive particles on the insulating sheet within 1 mm 2 In addition, for particles present within the screen (actual scale: 0.5 mm x 0.5 mm), the distance between adjacent particles was measured to calculate the standard deviation of the interparticle distance, which was then divided by the average distance to calculate the CV value of the interparticle distance, and the variation in the interparticle distance was evaluated according to the following criteria. [Variation in interparticle distance] A: CV value is less than 40%. B: CV value is over 40%.

[0122] Example 2 Conductive particles were adsorbed onto an insulating sheet in the same manner as in Example 1, except that blended particles 2 were used instead of blended particles 1, and the number of particles was measured and the variation in interparticle distance was evaluated.

[0123] Example 3 Conductive particles were adsorbed onto an insulating sheet in the same manner as in Example 1, except that blended particles 3 were used instead of blended particles 1, and the number of particles was measured and the variation in interparticle distance was evaluated.

[0124] [Table 2] [Explanation of symbols]

[0125] 1,1'...electrostatic adsorption device, 2...positioning section, 3...electrode body, 4...lower electrode (first electrode), 5...adsorption section, 6...electrode body, 7...upper electrode (second electrode), 8,8'...power supply, 9,9'...control section, 10...mediator particle, 12...conductive particle, 20...electrode with conductive particle, 22,22a...second adsorption section, 30...recess, 40,50...roller electrode, P...blended particles.

Claims

1. a step of forming an electric field between a first electrode having an arrangement portion having electrostatic dissipation properties or conductivity, and a second electrode having an adsorption portion facing the arrangement portion, thereby causing a blended particle, which is arranged in the arrangement portion and has conductive particles having a particle size smaller than that of the mediator particles attached thereto, to move back and forth between the arrangement portion and the adsorption portion, thereby adsorbing the conductive particles to the adsorption portion; A method for dispersing conductive particles, wherein a mass ratio of the conductive particles to the medium particles in the mixed particles is 1:500 to 1:1500.

2. a step of forming an electric field between a first electrode having an arrangement portion having electrostatic dissipation properties or conductivity, and a second electrode having an adsorption portion facing the arrangement portion, thereby causing a blended particle, which is arranged in the arrangement portion and has conductive particles having a particle size smaller than that of the mediator particles attached thereto, to move back and forth between the arrangement portion and the adsorption portion, thereby adsorbing the conductive particles to the adsorption portion; The conductive particle dispersion method, wherein the volume ratio of the conductive particles to the intermediate particles in the mixed particles is 1:900 to 1:2600.

3. a step of forming an electric field between a first electrode having an arrangement portion having electrostatic dissipation properties or conductivity, and a second electrode having an adsorption portion facing the arrangement portion, thereby causing a blended particle, which is arranged in the arrangement portion and has conductive particles having a particle size smaller than that of the mediator particles attached thereto, to move back and forth between the arrangement portion and the adsorption portion, thereby adsorbing the conductive particles to the adsorption portion; The method for dispersing conductive particles, wherein the ratio of the number of the conductive particles to the number of the intermediate particles in the mixed particles is 30:1 to 100:

1.

4. the arrangement portion has a recess that opens to the adsorption portion side, the recess has an inner wall surface that is tapered so that an opening width increases toward the suction portion, The method for dispersing conductive particles according to claim 1 , wherein the blended particles are placed in the recesses.

5. The conductive particle dispersion method according to any one of claims 1 to 3, further comprising a step of electrostatically adsorbing the conductive particles adsorbed on the adsorption portion to a second adsorption portion having insulating properties and arranged to face the adsorption portion.

6. 4. The method for dispersing conductive particles according to claim 1, wherein the medium particles are carbon particles having an average particle size of 100 to 150 μm.

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