TW201628024A - Connector inspection method, connector, conductive particle and anisotropic conductive adhesive - Google Patents

Abstract

Provided is a connector inspection method allowing a conductive particle to be inspected readily and rapidly after connector production; also provided are a connector, a conductive particle and an anisotropic conductive adhesive. In the inspection method for a connector wherein transparent electrodes (19, 21) formed on a transparent substrate (12) and connection terminals (23, 25) from an electronic component (18) are connected via an anisotropic conductive adhesive (1), a conductive particle (4) sandwiched between the transparent electrodes (19, 21) and the connection terminals (23, 25) comprises a resin core (4a) covered by a conductive layer (4b), has the resin core (4a) colored in a different color from the connection terminals (23, 25), and is caught above the transparent electrodes (19, 21). The method detects that the surface of the resin core (4a) has been exposed via the color of the resin core.

Description

Connector inspection method, connector, conductive particles and anisotropic conductive adhesive

The present invention relates to an inspection method and a connector for connecting a transparent electrode formed on a transparent substrate and a connection terminal of an electronic component via an anisotropic conductive connection, and more particularly to a method of being trapped between a transparent electrode and a connection terminal. A method for inspecting a connector having improved visibility of conductive particles, a linker, conductive particles, and an anisotropic conductive adhesive.

The present application claims priority on the basis of the Japanese Patent Application No. 2014-250384 filed on Dec. 10, 2014, the entire disclosure of which is hereby incorporated by reference.

Liquid crystal display devices or organic EL panels have been used in the past as various display means such as televisions or PC displays, mobile phones or smart phones, portable game machines, tablet terminals or wearable terminals, or display devices for vehicles. In such a display device, a driving substrate is directly mounted on a glass substrate of a display panel by using an anisotropic conductive film (ACF: Anisotropic Conductive Film) from the viewpoints of fine pitch, light weight, and the like. The above method or a method of directly mounting a flexible substrate on which a drive circuit or the like is formed on a glass substrate.

A plurality of transparent electrodes made of ITO (Indium Tin Oxide) or the like are formed on a glass substrate on which an IC or a flexible substrate is mounted, and an electronic component such as an IC or a flexible substrate is connected to the transparent electrode. The electronic component connected to the glass substrate forms a plurality of electrode terminals corresponding to the transparent electrode on the mounting surface. The anisotropic conductive film is thermocompression bonded to the glass substrate, whereby the electrode terminal is connected to the transparent electrode.

The anisotropic conductive film is obtained by mixing conductive particles into a binder resin and forming a film. The electrical conduction between the conductors is performed by the conductive particles by heating and pressure bonding between the two conductors, and the adhesive is used. The resin holds the mechanical connection between the conductors. As the adhesive constituting the anisotropic conductive film, a thermosetting adhesive resin having high reliability is generally used, and a photocurable adhesive resin or a photo-heat-adhesive adhesive resin may be used.

In the case where the electronic component is connected to the transparent electrode via such an anisotropic conductive film, first, the anisotropic conductive film is temporarily attached to the transparent electrode of the glass substrate by a temporary pressure bonding means. Then, an electronic component is mounted on the glass substrate via the anisotropic conductive film to form a temporary connection body, and thereafter, the electronic component and the anisotropic conductive film are collectively heated to the transparent electrode side by a thermocompression bonding means such as a thermal head. Push. By the heating of the thermal head, the anisotropic conductive film undergoes a thermosetting reaction, whereby the electronic component is attached to the transparent electrode.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-26577

As the conductive particles sandwiched between the transparent electrode of the glass substrate and the connection terminal of the electronic component such as the IC chip, a conductive layer is generally formed by plating a conductive material such as nickel or gold on the surface of the resin core. The conductive particles sandwiched between the transparent electrode and the connection terminal are electrically connected to the connection terminal via the conductive layer.

Here, the conductive particles may be peeled off from the surface of the resin core due to friction with the transparent electrode or the connection terminal due to accidental vibration during crimping at the time of the anisotropic connection. Further, the conductive particles may be eluted by an acid or the like generated by the binder resin during the treatment at the time of the anisotropic connection or before or after the treatment. As described above, when the conductive particles are sandwiched between the transparent electrode and the connection terminal in a state where the surface of the resin core is exposed, the conductivity is impaired.

This phenomenon occurs when all of the conductive particles are trapped between a set of transparent electrodes and the connection terminals, and also in a plurality of conductive particles trapped between a set of transparent electrodes and the connection terminals. a situation that arises.

In a connection body in which an electronic component such as a glass substrate and an IC or a flexible substrate is connected to each other in an anisotropic manner, it is considered that there are a plurality of factors for reducing the conductivity, but the substrate or the electronic component is reduced by the miniaturization of the electronic device or the like. The thinning, the fine pitch of the wiring, etc., the determination of the factors also requires a considerable number of steps and time. In other words, in order to improve the yield, it is strongly required that the early detection of the conduction failure is caused by the component member side of the connector such as a glass substrate or an electronic component, or the peeling or elution of the conductive layer due to the conductive particles, or the cause thereof. Insufficient press-fitting of conductive particles occurs due to alignment of the thermocompression bonding step, setting of the thermocompression bonding tool, or accuracy, and seeks improvement measures.

Therefore, if the conductive particles are easily peeled off or eluted, or whether the measurement between the transparent electrode and the connection terminal is sufficiently performed, the burden of the inspection step can be reduced.

However, the resin core of the conductive particles is observed to be colorless or translucent, and if the conductive layer is peeled off or eluted, it is difficult to grasp the position or damage of the conductive particles caught on the connection terminals.

Accordingly, an object of the present invention is to provide a method for inspecting a connector, a connector, conductive particles, and an anisotropic conductive adhesive which can easily and quickly perform inspection of conductive particles after the production of a connector.

In order to solve the above problems, the method for inspecting a connector of the present invention is a method for inspecting a connector formed by connecting an interface between a transparent electrode of a transparent substrate and an electronic component with an anisotropic conductive adhesive. The conductive particles between the transparent electrode and the connection terminal are formed by coating a resin core with a conductive layer, and the resin core is colored in a color different from the connection terminal, and the color of the resin core is detected and captured. Conductive particles which are exposed on the surface of the resin core on the transparent electrode.

Further, in the connection system of the present invention, the connection terminals of the transparent electrode and the electronic component formed on the transparent substrate are connected by an anisotropic conductive adhesive, and the conductive particles sandwiched between the transparent electrode and the connection terminal are formed. The resin core is coated with a conductive layer, and the resin core is colored differently from the connection terminal, and the conductive particles trapped on the transparent electrode can be visually recognized by the color of the resin core. The surface of the resin core is exposed.

Further, the conductive particles of the present invention include a resin core and a conductive layer covering the surface of the resin core, which is contained in an adhesive which is formed by anisotropic conductive connection between a transparent electrode of a transparent substrate and a connection terminal of an electronic component. The resin core is colored in a color different from the connection terminal, and the surface of the resin core can be visually recognized by the color of the resin core.

Further, the anisotropic conductive adhesive of the present invention contains conductivity in a binder resin. And connecting the transparent electrode formed on the transparent substrate to the connection terminal of the electronic component, wherein the conductive particle has a resin core and a conductive layer covering the surface of the resin core, and the resin core is colored differently from the connection terminal. The color of the resin core can be visually recognized by the color of the resin core.

According to the invention, the conductive particle-based resin core sandwiched between the transparent electrode and the connection terminal is covered with the conductive layer, and at least a part of the resin core is colored differently from the connection terminal, so that it is captured after the crimping When the conductive particles of the connection terminal are exposed, the surface of the resin core is exposed, the visibility can be improved, and the degree of peeling or elution of the conductive layer or the damage of the conductive particles can be easily grasped.

1‧‧‧ anisotropic conductive film

2‧‧‧Release film

3‧‧‧Binder resin layer

4‧‧‧Electrical particles

4a‧‧‧ resin core

4b‧‧‧ Conductive layer

6‧‧‧Reel reel

10‧‧‧LCD panel

11, 12‧‧‧ Transparent substrate

12a‧‧‧Edge

13‧‧‧ Sealing material

14‧‧‧LCD

15‧‧‧ Panel display

16, 17‧‧ ‧ transparent electrode

18‧‧‧LCD driver IC

18a‧‧‧Installation surface

19‧‧‧Input terminal

20‧‧‧Input terminal line

21‧‧‧Output terminal

22‧‧‧Output terminal line

23‧‧‧ Input bumps

25‧‧‧Output bumps

24‧‧‧Input bump row

26‧‧‧Output bump row

27‧‧‧Installation Department

33‧‧‧Hot head

Fig. 1 is a cross-sectional view showing a liquid crystal display panel as an example of a connector.

Fig. 2 is a plan view showing a mounting portion of a transparent substrate.

3 is a cross-sectional view showing a step of connecting a liquid crystal driving IC and a transparent substrate.

4 is a plan view showing a mounting surface of a liquid crystal driving IC.

Fig. 5 is a cross-sectional view showing an anisotropic conductive film.

Fig. 6 is a cross-sectional view showing conductive particles.

Fig. 7 is a bottom view of the conductive particles captured by bumps as viewed from the back side of the transparent substrate of the connector, and (A) shows conductive particles in which the conductive layer is not peeled off and eluted, and (B) shows The conductive particles which are laminated on the conductive layer of the colored resin core are peeled off and eluted, and (C) show the conductive particles which are laminated and eluted from the conductive layer of the uncolored resin core.

Hereinafter, the method of inspecting the connector, the connecting body, the conductive particles, and the anisotropic conductive adhesive to which the present invention is applied will be described in detail with reference to the drawings. In addition, the present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention. Moreover, the drawings are schematic, and the ratio of each size may be different from the actual situation. The specific dimensions and the like should be judged by considering the following instructions. Moreover, it is undoubted that the schemas also contain different parts of the relationship or ratio of the dimensions.

[Liquid Crystal Display Panel]

In the connecting body to which the present invention is applied, a liquid crystal display panel in which an IC chip for driving a liquid crystal is mounted on a glass substrate as an electronic component will be described as an example. As shown in FIG. 1, the liquid crystal display panel 10 is disposed to face the two transparent substrates 11 and 12 which are formed of a glass substrate or the like, and the transparent substrates 11 and 12 are bonded to each other by a frame-shaped sealing member 13. Further, the liquid crystal display panel 10 is formed with the panel display portion 15 by enclosing the liquid crystal 14 in a space surrounded by the transparent substrates 11 and 12.

The transparent substrates 11 and 12 are formed such that one of the stripe shapes formed of ITO (indium tin oxide) or the like on the inner side surfaces facing each other intersects the transparent electrodes 16 and 17 so as to intersect each other. Further, the two transparent electrodes 16 and 17 constitute pixels which are the smallest unit of liquid crystal display by the intersection of the two transparent electrodes 16 and 17.

Among the two transparent substrates 11 and 12, one transparent substrate 12 is formed larger than the other transparent substrate 11, and the edge portion 12a of the largely formed transparent substrate 12 is provided with a mounting portion for mounting the liquid crystal driving IC 18 as an electronic component. 27. Furthermore, the mounting portion 27 is as shown in FIG. 2. The output terminal row 22 in which the input terminal row 20 and the plurality of output terminals 21 in which the plurality of input terminals 19 in which the transparent electrodes 17 are formed are arranged as shown in FIG. 3 is aligned with the IC side provided on the liquid crystal driving IC 18. The substrate side alignment mark 31 is overlapped by the mark 32.

The mounting portion 27 has, for example, a first terminal region 27a in which one input terminal row 20 is formed, and a second terminal region in which two output terminal rows 22a and 22b which are arranged in the width direction orthogonal to the array direction of the output terminal 21 are formed. 27b. The output terminal 21 and the output terminal row 22 have the first output terminal row 22a in which the first output terminal 21a is arranged on the inner side, that is, the input terminal row 20 side, and the second output terminal 21b on the outer edge side of the mounting portion 27 on the outer side. The second output terminal row 22b.

The liquid crystal driving IC 18 can perform a specific liquid crystal display by selectively applying a liquid crystal driving voltage to a pixel to partially change the alignment of the liquid crystal. Further, as shown in FIGS. 3 and 4, the liquid crystal driving IC 18 is formed by arranging a plurality of input bumps 23 that are electrically connected to the input terminal 19 of the transparent electrode 17 to the mounting surface 18a of the transparent substrate 12. The block row 24 and the output bump row 26 in which the plurality of output bumps 25 electrically connected to the output terminal 21 of the transparent electrode 17 are arranged are arranged.

The liquid crystal driving IC 18 has, for example, a first bump region 18b in which the input bumps 23 are arranged in one row along one side edge of the mounting surface 18a, and two output bumps juxtaposed in the width direction orthogonal to the array direction of the output bumps 25. The second bump region 18c formed by the block rows 26a and 26b. The output bump 25 and the output bump row 26 have the first output bump row 26a in which the first output bumps 25a are arranged on the inner side of the input bump row 24, and the outer edge side of the mounting surface 18a on the outer side. 2 The second output bump row 26b in which the output bumps 25b are arranged.

The first and second output bumps 25a, 25b are along the other side edge opposite to one side edge Multiple rows are misaligned. The input/output bumps 23 and 25 and the input/output terminals 19 and 21 provided on the mounting portion 27 of the transparent substrate 12 are formed at the same number and at the same pitch, and are connected to each other by the transparent substrate 12 and the liquid crystal driving IC 18 in alignment.

Furthermore, the arrangement of the input and output bump rows 24 and 26 of the first and second bump regions 18b and 18c may be a row of bump rows 24 on one side of the mounting surface 18a, as shown in FIG. Or the plurality of rows are arranged, and the output bump row 26 is arranged on the other side edge in any one or more rows. Further, with respect to the input/output bump rows 24, 26, one of the input and output bumps 23, 25 arranged in one line may be a plurality of rows, and one of the input and output bumps 23, 25 arranged in a plurality of rows may also be a row. Further, with respect to the input/output bump rows 24, 26, the arrangement of the input and output bumps 23, 25 of the plurality of rows may be formed by parallel and adjacent bumps arranged in parallel with each other, or a plurality of rows of input and output bumps 23 The arrangement of 25 may be formed by paralleling and arranging the adjacent bumps evenly shifted from each other.

Further, the liquid crystal driving IC 18 arranges the input/output bumps 23 and 25 along the long sides of the IC substrate, and may form side bumps along the short sides of the IC substrate. Furthermore, the input and output bumps 23, 25 may be formed in the same size or may be formed in different sizes. Further, regarding the input/output bump rows 24 and 26, the input and output bumps 23 and 25 formed in the same size may be symmetrically or asymmetrically arranged, and the input and output bumps 23 and 25 formed in different sizes may also be arranged asymmetrically. .

In addition, with the miniaturization and high functionality of liquid crystal display devices and other electronic devices in recent years, electronic components such as the liquid crystal driving IC 18 have also been reduced in size and low in height, and the heights of the input/output bumps 23 and 25 have also become low. (eg 6~15μm).

Further, the liquid crystal driving IC 18 is formed with an IC side alignment mark 32 that is aligned with the transparent substrate 12 by the mounting surface 18a overlapping the substrate side alignment mark 31. Furthermore, When the wiring pitch of the transparent electrode 17 of the transparent substrate 12 or the pitch of the input/output bumps 23 and 25 of the liquid crystal driving IC 18 is progressing, the liquid crystal driving IC 18 and the transparent substrate 12 are adjusted in alignment with high precision.

The substrate side alignment mark 31 and the IC side alignment mark 32 can use various marks for achieving alignment of the transparent substrate 12 and the liquid crystal driving IC 18 by combination.

The input/output terminals 19 and 21 of the transparent electrode 17 of the mounting portion 27 are formed, and the liquid crystal driving IC 18 is connected by using the anisotropic conductive film 1 as an adhesive for circuit connection. The anisotropic conductive film 1 contains the conductive particles 4, and the input/output bumps 23 and 25 of the liquid crystal driving IC 18 and the input and output terminals of the transparent electrode 17 formed on the mounting portion 27 of the transparent substrate 12 via the conductive particles 4 are provided. 19, 21 electrical connectors. The anisotropic conductive film 1 is thermocompression-bonded by the thermal head 33, whereby the binder resin is fluidized, and the conductive particles 4 are input and output terminals 19 and 21 and the input/output bumps 23 of the liquid crystal driving IC 18, 25 is crushed, and the binder resin hardens in this state. Thereby, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 and the liquid crystal driving IC 18.

Further, an alignment film 28 subjected to a specific rubbing treatment is formed on the two transparent electrodes 16 and 17, and the alignment film 28 restricts the initial alignment of the liquid crystal molecules. Further, a pair of polarizing plates 29a and 29b are disposed on the outer sides of the transparent substrates 11 and 12, and the two polarizing plates 29a and 29b restrict the vibration direction of the transmitted light from a light source (not shown) such as a backlight.

[Anisotropic conductive film]

Next, the anisotropic conductive film 1 will be described. As shown in FIG. 5, an anisotropic conductive film (ACF: Anisotropic Conductive Film) 1 is usually formed with a binder resin layer (adhesive layer) 3 containing conductive particles 4 on a release film 2 serving as a substrate. The anisotropic conductive film 1 is a thermosetting type Or a photocurable adhesive such as an ultraviolet ray, which is bonded to the mounting portion 27 of the transparent substrate 12 of the liquid crystal display panel 10 on which the input/output terminals 19 and 21 are formed, and the liquid crystal driving IC 18 is mounted by using the thermal head 33. This is fluidized by hot pressing, and the conductive particles 4 are crushed between the input/output terminals 19 and 21 of the transparent electrode 17 and the input/output bumps 23 and 25 of the liquid crystal driving IC 18, and are heated or ultraviolet ray. Upon irradiation, the conductive particles 4 are hardened in a crushed state. Thereby, the anisotropic conductive film 1 can connect the transparent substrate 12 and the liquid crystal driving IC 18, and can be electrically connected.

Further, the anisotropic conductive film 1 is obtained by blending the conductive particles 4 with a usual binder resin layer 3 containing a film-forming resin, a thermosetting resin, a latent curing agent, a decane coupling agent or the like.

The release film 2 supporting the binder resin layer 3 is, for example, a release agent such as PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), or PTFE (Polytetrafluoroethylene). It is formed to prevent drying of the anisotropic conductive film 1 and to maintain the shape of the anisotropic conductive film 1.

The film-forming resin contained in the binder resin layer 3 is preferably a resin having an average molecular weight of about 10,000 to 80,000. Examples of the film-forming resin include various resins such as an epoxy resin, a deformed epoxy resin, an urethane resin, and a phenoxy resin. Among them, a phenoxy resin is particularly preferable from the viewpoints of film formation state, connection reliability, and the like.

The thermosetting resin is not particularly limited, and examples thereof include commercially available epoxy resins and acrylic resins.

The epoxy resin is not particularly limited, and examples thereof include a naphthalene type epoxy resin, a biphenyl type epoxy resin, a phenol novolak type epoxy resin, a bisphenol type epoxy resin, a fluorene type epoxy resin, and a trisphenol methane. Epoxy resin, phenol aralkyl epoxy resin, naphthol epoxy resin, Dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, and the like. These may be used alone or in combination of two or more.

The acrylic resin is not particularly limited, and an acrylic compound, a liquid acrylate or the like can be appropriately selected depending on the purpose. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylic acid Ester, dimethylol tricyclodecane diacrylate, butanediol tetraacrylate, 2-hydroxy-1,3-dipropenyloxypropane, 2,2-bis[4-(acrylomethoxy group) Oxy)phenyl]propane, 2,2-bis[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecenyl acrylate, tris(propylene decyloxy) Ethyl)isocyanurate, urethane acrylate, epoxy acrylate, and the like. Further, those in which the acrylate is methacrylate can also be used. These may be used alone or in combination of two or more.

The latent curing agent is not particularly limited, and examples thereof include various curing agents such as a heat curing type and a UV curing type. The latent hardener does not react under normal conditions, and is activated by various triggers selected depending on the use of heat, light, pressure, etc., and starts the reaction. In the activation method of the heat-active latent hardener, there is a method of generating an active species (cation or anion, radical) by a dissociation reaction based on heating, and stably dispersing in an epoxy resin at a high temperature and at a high temperature. A method of dissolving and dissolving in an epoxy resin to start a hardening reaction; a method of starting a hardening reaction by eluting a molecular sieve-sealed hardener at a high temperature; a method of eluting and hardening based on a microcapsule, and the like. Examples of the thermally active latent curing agent include an imidazole-based, an anthraquinone-based, a boron trifluoride-amine complex, an onium salt, an amine imide, a polyamine salt, a dicyandiamide, or the like, or the like. These may be used singly or in a mixture of two or more kinds. Among them, a microcapsule type imidazole-based latent curing agent is preferred.

The decane coupling agent is not particularly limited, and examples thereof include an epoxy group and an amine group. Mercapto-sulfanyl, urea-based, and the like. The adhesion of the interface between the organic material and the inorganic material is improved by adding a decane coupling agent.

[conductive particles]

[resin core]

As shown in FIG. 6, the conductive particles 4 have a resin core 4a and a conductive layer 4b covering the resin core 4a. The resin core 4a is colored differently from the input bump 23 and the output bump 25 of the liquid crystal driving IC 18. As the resin core 4a, it is preferable to use particles composed of a plastic material excellent in compression deformation, and for example, a (meth) acrylate resin, a polystyrene resin, or a styrene-(meth)acrylic copolymer resin can be used. An amine ester resin, an epoxy resin, a phenol resin, an acrylonitrile-styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, a polyester resin or the like is formed.

For example, when the resin core 4a is formed using a (meth) acrylate-based resin, the (meth)acrylic resin is preferably a (meth) acrylate and, if necessary, a reactive double copolymerizable therewith. A compound of a bond and a copolymer of a difunctional or polyfunctional monomer.

Further, when the resin core 4a is formed of a polystyrene resin, the polystyrene resin is preferably a derivative of styrene and, if necessary, a compound having a reactive double bond copolymerizable therewith, and a difunctional group. Or a copolymer of a polyfunctional monomer.

In the case where the conductive particles 4 of the present invention have the resin core 4a composed of a (meth)acrylic resin, the (meth)acrylic resin is preferably (meth)acrylate (total) As the polymer, a copolymer of the (meth) acrylate monomer and another monomer can also be used.

Here, as an example of a (meth)acrylate type monomer, (meth) C is mentioned. Methyl enoate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, ( Stearic acid methyl methacrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-propyl (meth) acrylate, chloro-2- hydroxy (meth) acrylate Ester, diethylene glycol mono(meth)acrylate, methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (meth)acrylic acid Cyclopentenyl ester and isobornyl (meth)acrylate.

In the case where the resin core 4a of the conductive particles of the present invention is a polystyrene resin, specific examples of the styrene monomer include styrene, methyl styrene, and dimethyl styrene. , alkyl groups such as trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene Styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodine styrene and chloromethylstyrene; and nitrostyrene, ethyl styrene styrene and methoxybenzene Ethylene.

The resin core 4a is preferably formed of any one of the above-mentioned (meth)acrylic resin or styrene resin, or may be formed of a composition composed of the resins. Further, it may be a copolymer of the above (meth)acrylate-based monomer and a styrene-based monomer.

Further, the (meth)acrylic resin or the styrene resin may be a monomer such as the above (meth)acrylate-based monomer and/or a styrene-based monomer, and may be copolymerized as needed. The monomers are copolymerized.

Examples of the other monomer copolymerizable with the above (meth)acrylate-based monomer or styrene-based monomer include a vinyl monomer and an unsaturated carboxylic acid monomer.

A resin core is exemplified as an example of the resin core 4a made of an acrylic resin. 4a is composed of a polymer of an acrylic monomer, and may be composed, for example, of a monomeric polymer containing an amine ester compound and an acrylate.

Here, the acrylic single system refers to both an acrylate and a methacrylate. Further, in the invention of the present invention, if the monomer is polymerized by heating or ultraviolet irradiation or the like, an oligomer which is a polymer of two or more monomers is also contained.

In the case where the acrylic resin constituting the resin core 4a of the present invention is composed of a monomer polymer containing an amine ester compound and an acrylate, the amine ester compound is preferably contained in an amount of 5 parts by weight or more based on 100 parts by weight of the monomer. More preferably, it contains 25 parts by weight or more.

As the amine ester compound, a polyfunctional acrylate can be used, and for example, a bifunctional acrylate or the like can be used.

〔Colorant〕

Further, at least a part or all of the resin core 4a is colored by a coloring agent to have a color different from that of the input bump 23 and the output bump 25 of the liquid crystal driving IC 18. Thereby, when the resin core 4a is peeled or eluted by the conductive layer 4b and the surface of the resin core 4a is exposed, visibility can be improved.

When the resin core 4a is colored, for example, when the resin core 4a is made of an acrylic resin, the resin can be polymerized by adding a filler which is a colorant, and formed by a polystyrene resin. In the case of the resin core 4a, it can be carried out by adding a filler which is a colorant and polymerizing the styrene monomer.

Further, the resin core 4a is colored to have a complementary color (opposite color) to the color of the input/output bumps 23 and 25, thereby improving visibility. The complementary color (opposite color) refers to the color on the opposite side of the hue circle. Specifically, when the object color is placed at the center of one of the regions uniformly formed by the four-division phase-phase loop, the complementary color (opposite color) means that it does not belong to the object color. The color of the area adjacent to the area.

Further, when the surface of the input/output bumps 23 and 25 is covered with a white conductive layer, the resin core 4a is preferably colored by a black-based filler. Further, when the surface of the input/output bumps 23 and 25 is covered with a conductive layer having a yellow metallic luster such as gold, the resin core 4a can be colored by a white filler.

For example, when the input/output bumps 23 and 25 are covered with a material having metallic luster such as gold, silver or copper constituting a conductive material on the surface thereof, the resin core 4a is preferably white by titanium oxide or the like. Filler coloring. In the case where the input/output bumps 23 and 25 are covered with a white material such as zinc as a conductive material constituting the surface thereof, the resin core 4a is preferably black such as titanium black, carbon black or iron oxide. Filler coloring.

Further, the coloring agent that colors the resin core 4a has insulating properties. For example, the colorant is preferably one having a dielectric resistance of 1 × 10 ⁸ Ω/cm or more as measured under the conditions of 25 ° C and 70% RH. The above insulation resistance can be measured, for example, by a general insulation resistance meter. Coloring is performed by an insulating coloring agent, whereby it is easy to specify a factor of occurrence of migration or the like.

Further, the coloring agent that colors the resin core 4a may be a conductive material. By coloring with a conductive coloring agent, the on-resistance values of the input/output bumps 23 and 25 and the input/output terminals 19 and 21 connected via the conductive particles 4 can be easily reduced.

Further, the size of the filler which colors the resin core 4a is preferably less than 30%, more preferably 20% or less, still more preferably 10% or less of the particle diameter of the conductive particles 4. The reason for this is that when the size of the filler colored with the resin core 4a is 30% or more of the particle diameter of the conductive particles 4, the elasticity of the conductive particles 4 is lowered, and immediately after the anisotropic connection or the reliability test The latter cannot follow the change of the gap between the input/output bumps 23, 25 and the input/output terminals 19, 21, Incurs the rise in the value of the on-resistance.

Further, the filler which colors the resin core 4a is preferably spherical. As will be described later, the reason for this is that the damage state and the like can be easily compared when the connector is inspected.

Further, the size of the filler which colors the resin core 4a is preferably uniform. Specifically, it is preferred that 90% of the total number of fillers used is within ±20% of the average diameter of the filler. Thereby, the compressed state of the conductive particles can be easily determined in the inspection of the bonded body.

Moreover, the blending amount of the filler which colors the resin core 4a is preferably 30 vol% or less. When the blending amount of the filler is more than 30 vol%, the elasticity of the conductive particles 4 is impaired, and the connection reliability is lowered. Further, the blending amount of the filler is preferably 2 vol% or more. If the blending amount of the filler is less than 2 vol%, the visibility of the resin core 4a cannot be improved.

[conductive layer]

Further, in the conductive particles 4 of the present invention, the conductive layer 4b formed on the surface of the resin core 4a can be a conductive metal generally used as a conductive layer of conductive particles, an alloy containing the metals, and a conductive metal. Formed by oxide or other conductive material. For example, the conductive layer 4b is formed of Ni, a Ni alloy, Au, or the like.

Further, the conductive layer 4b may be subjected to a physical method such as a vapor deposition method, an ion sputtering method, an electroless plating method, or a sputtering method; a chemical method in which a conductive material is scientifically bonded to a surface of a resin core having a functional group; The active agent or the like is formed by a method of adsorbing a conductive material on the surface of the resin core or the like. Such a conductive layer 4b does not have to be a single layer, and a plurality of layers may be laminated.

The thickness of such a conductive layer 4b is usually in the range of 0.01 to 10.0 μm, preferably 0.05 to 5 μm, and more preferably 0.2 to 2 μm. An insulating layer made of an insulating resin may be further formed on the surface of the conductive layer 4b. As a method of forming an insulating layer, an example For example, if an example of a method of forming a discontinuous insulating layer made of polyvinylidene fluoride by a mixing system is exemplified, 2 to 8 parts by weight of polyvinylidene fluoride is used with respect to 400 parts by weight of the conductive particles. And it is treated at 85~115 °C for 5~10 minutes. The thickness of the insulating layer is usually about 0.1 to 0.5 μm. Furthermore, the insulating layer may not completely cover the surface of the conductive particles.

In the case where the conductive particles 4 of the present invention are used for an anisotropic conductive bonding material (an anisotropic conductive film), the conductive particles 4 may have a thickness of usually 1 to 50 μm, preferably 3 to 10 μm. Average particle size.

In addition, the shape of the anisotropic conductive film 1 is not particularly limited, and for example, as shown in FIG. 5, it can be used in a long strip shape which can be wound around the take-up reel 6, and can be used only by cutting a specific length.

In the above-described embodiment, the adhesive film composition in which the conductive resin particles 4 are blended into the adhesive resin layer 3 is formed into a film shape. Although the example of the adhesive agent of the present invention is not limited thereto, for example, an insulating adhesive layer composed of only the binder resin 3 and an adhesive resin 3 doped with the conductive particles 4 may be used. The conductive particles are composed of a layer. Further, in the present invention, an anisotropic conductive paste composed of a binder resin composition obtained by blending the conductive particles 4 with the binder resin layer 3 may be used. The anisotropic conductive adhesive of the present invention contains both the anisotropic conductive film 1 and the anisotropic conductive paste.

[bump material]

The input/output bumps 23 and 25 that capture such conductive particles 4 are formed of a conductive metal, an alloy containing the metals, a conductive ceramic, a conductive metal oxide, or another conductive material.

Examples of the conductive metal include Zn, Al, Sb, U, Cd, Ga, Ca, Au, Ag, Co, Sn, Se, Fe, Cu, Th, Pb, Ni, Pd, Be, and Mg. Further, the above metals may be used singly or in combination of two or more kinds, and other elements, compounds (for example, solder) may be further added. Examples of the conductive ceramics include Vo ₂ , Ru ₂ O, SiC, ZrO ₂ , Ta ₂ N, ZrN, NbN, VN, TiB ₂ , ZrB, HfB ₂ , TaB ₂ , MoB ₂ , CrB ₂ , and B _{4 .} C, MoB, ZrC, VC and TiC. Further, examples of the conductive material other than the above include carbon particles such as carbon and graphite, and ITO.

Among such conductive materials, it is particularly preferable to contain gold in the input/output bumps 23 and 25. By making the input and output bumps 23, 25 contain gold, the resistance value becomes low, and the ductility becomes good, and good conductivity can be obtained. Further, since the hardness of gold is low, the isotropic conductive bonding material (the anisotropic conductive film or the anisotropic conductive paste) containing the conductive particles 4 is used to conduct electricity between the input/output terminals 19 and 21 as will be described later. In the case of connection, there is less damage.

As the input/output bumps 23 and 25, for example, it is preferable to use a gold (Au) layer on the surface of a nickel (Ni) metal layer (substituted by gold (Au)).

[Connection step]

Next, a connection procedure of connecting the liquid crystal driving IC 18 to the transparent substrate 12 will be described. First, the anisotropic conductive film 1 is temporarily attached to the mounting portion 27 of the transparent substrate 12 on which the input/output terminals 19 and 21 are formed. Then, the transparent substrate 12 is placed on the mounting table of the connection device, and the liquid crystal driving IC 18 is placed on the mounting portion 27 of the transparent substrate 12 via the anisotropic conductive film 1.

Then, the thermal head 33 heated to a specific temperature at which the adhesive resin layer 3 is cured is thermally pressurized from the liquid crystal driving IC 18 at a specific pressure and time. Thereby, the adhesive resin layer 3 of the anisotropic conductive film 1 exhibits fluidity, flows out from between the mounting surface 18a of the liquid crystal driving IC 18 and the mounting portion 27 of the transparent substrate 12, and conductivity in the adhesive resin layer 3. particle 4 is sandwiched between the input/output bumps 23 and 25 of the liquid crystal driving IC 18 and the input/output terminals 19 and 21 of the transparent substrate 12, and is crushed.

As a result, the conductive particles 4 are sandwiched between the input/output bumps 23 and 25 and the input/output terminals 19 and 21, and the adhesive resin heated by the thermal head 33 is hardened in this state. Thereby, the liquid crystal display panel 10 which ensures the continuity between the input/output bumps 23 and 25 of the liquid crystal drive IC 18 and the input/output terminals 19 and 21 formed in the transparent substrate 12 can be manufactured. Further, as shown in FIG. 7, the liquid crystal display panel 10, the conductive particles 4 sandwiched between the input/output bumps 23, 25 and the input and output terminals 19, 21 can be transparent from the background of the input and output bumps 23, 25. The back side of the substrate 12 is observed.

The conductive particles 4 not between the input/output bumps 23, 25 and the input and output terminals 19, 21 are dispersed in the adhesive resin in the space 35 between the adjacent input and output bumps 23, 25, and the electrical insulation is maintained. status. Therefore, the liquid crystal display panel 10 is electrically connected only between the input/output bumps 23 and 25 of the liquid crystal driving IC 18 and the input/output terminals 19 and 21 of the transparent substrate 12. Further, the anisotropic conductive film 1 is not limited to a thermosetting type, and a photocurable or photothermal combination type adhesive may be used for the pressure connection.

[checking step]

As described above, in the liquid crystal display panel 10, the conductive particles 4 sandwiched between the input/output bumps 23 and 25 and the input/output terminals 19 and 21 can be viewed from the back side of the transparent substrate 12 and delivered to the visual inspection. As shown in FIG. 7(A), the conductive particles 4 in which the conductive layer 4b is not peeled off or eluted can be visually recognized by the input/output bumps 23 and 25, and the number of captured particles or the damage state can be easily determined.

Here, the conductive particles 4 are present in the case where they are connected by an anisotropic Unexpected vibration occurs during crimping and rubs against the input/output terminals 19, 21 or the input/output bumps 23, 25, so that the conductive layer 4b is peeled off from the surface of the resin core 4a, or when it is treated by anisotropic connection or before or after The conductive layer 4b is eluted by an acid or the like generated by the binder resin, and the surface of the resin core 4a is exposed.

This phenomenon is caused by the fact that all of the conductive particles 4 captured between the set of input and output terminals 19, 21 and the input and output bumps 23, 25 are generated, and are also captured in a set of input and output terminals 19, 21 A case where several of the plurality of conductive particles 4 are interposed between the input and output bumps 23, 25. Further, peeling or elution of the conductive layer 4b occurs over the entire surface of the resin core 4a, and the entire surface of the resin core 4a is exposed.

At this time, the resin core 4a is colored in a different color from the input/output bumps 23 and 25, and the visibility of the conductive particles 4 which are peeled off or eluted by the conductive layer 4b is improved, and thus, as shown in FIG. 7(B), It is to be noted that even if the input/output bumps 23 and 25 are used as the background, the presence or absence of the conductive particles 4 in which the conductive layer 4b is peeled off or eluted, the damage state, and the like can be quickly inspected.

That is, as shown in Fig. 7(C), when the resin core 4c is not colored, even if the peeling or elution of the conductive layer 4b occurs and the resin core is exposed, the resin core 4c is generally transparent and translucent. Therefore, it is difficult to input or output the bumps 23 and 25 as a background to determine the presence or absence of the conductive particles in which the conductive layer 4b is peeled off or eluted. In this regard, the conductive particle 4 -based resin core 4a to which the present invention is applied is colored differently from the input/output bumps 23 and 25, so that the visibility at the time of peeling or elution of the conductive layer 4b is improved (FIG. 7 (FIG. 7) B)). Therefore, even if the input/output bumps 23 and 25 are used as the background, the presence or absence of the conductive particles 4 in which the conductive layer 4b is peeled off or eluted, the damage state, and the like can be quickly inspected.

In this case, in terms of improving the visibility, the resin core 4a is preferably coated with a conductive material having a yellow metallic luster such as gold when the surface of the input/output bumps 23 and 25 is covered. The white-based filler is colored, and when the surface of the input/output bumps 23, 25 is covered with a white-based conductive material, it is colored by a black-based filler.

For example, when the surface of the input/output bumps 23 and 25 is covered with a material having a metallic luster such as gold, silver or copper, the resin core 4a is preferably colored with a white filler such as titanium oxide. Further, when the surface of the input/output bumps 23 and 25 is covered with a white material such as zinc, the resin core 4a is preferably colored with a black filler such as titanium black, carbon black or iron oxide.

[Examples]

Next, an embodiment of the present invention will be described. In the present embodiment, an anisotropic conductive film for using conductive particles in which a resin core having a colored conductive layer is formed, and an anisotropic conductive film using conductive particles not colored with a resin core are used. A sample of the connector to which the evaluation IC was connected to the glass substrate for evaluation was prepared from each of the anisotropic conductive films, and the initial on-resistance of each of the connected samples and the on-resistance after the reliability test were measured, and the peeling of the conductive layer was evaluated. The visibility of conductive particles.

[Anisotropic conductive film]

The adhesive resin layer for the anisotropic conductive film for the connection of the evaluation IC is formed by using phenoxy resin (trade name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.) 60 parts by mass, epoxy resin. (product name: jER828, manufactured by Mitsubishi Chemical Corporation) 40 parts by mass, a cationic curing agent (trade name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), 2 parts by mass, added to a solvent to prepare a binder resin composition, and The binder resin composition is applied onto a release film and dried.

The conductive particles contained in the binder resin layer of the anisotropic conductive film form a conductive layer on the resin core which has been colored. The resin core was made of A-HD-N manufactured by Shin-Nakamura Chemical Industry Co., Ltd. as an acrylic monomer, and U-6LPA manufactured by Shin-Nakamura Chemical Industry Co., Ltd. was used. The urethane acrylate was prepared in a ratio of 60 parts by mass to 40 parts by weight, respectively. Titanium oxide (TIPAQUE R-820, a filler system: 0.26 μm manufactured by Ishihara Sangyo Co., Ltd.) was dispersed in the above-mentioned acrylic monomer and urethane acrylate as a coloring agent, and an acrylic resin particle was produced by emulsion polymerization.

The acrylic resin particles were coated with nickel by a sputtering method to obtain conductive particles having a particle diameter of 3.2 μm. The thickness of the nickel layer was 0.15 μm.

[Evaluation IC]

As the evaluation element, an evaluation IC in which bumps (electroplated gold) having a shape of 1.8 mm × 20 mm, a thickness of 0.5 mm, a width of 30 μm, a length of 85 μm, and a height of 15 μm were arranged in a plurality of rows was prepared. The bump surface of the evaluation IC has a metallic luster.

[Glass substrate for evaluation]

As the glass substrate for evaluation, an ITO-coated glass having a thickness of 0.7 mm was prepared.

After the anisotropic conductive film was temporarily attached to the evaluation glass substrate, the evaluation IC was mounted, and thermocompression bonding was performed at 170 ° C, 60 MPa, and 5 sec by a thermal head to prepare a molded body sample. The initial on-resistance and the on-resistance after the reliability test were measured for each of the connected body samples. In the reliability test, the connector sample was placed in a thermostat bath at a temperature of 85 ° C and a humidity of 85% RH for 500 hours.

For the initial on-resistance, it is assumed that less than 10 Ω is OK, and 10 Ω or more is set to NG. Further, the on-resistance after the reliability test is preferably less than 20 Ω, more preferably less than 10 Ω, further preferably less than 5 Ω, and 20 Ω or more is defective.

In addition, the conductive particles captured by the bumps of the IC for evaluation were observed from the back surface of the glass substrate for evaluation from the back surface of the glass substrate for evaluation, and the visibility of the conductive particles from which the conductive layer was peeled off was evaluated.

In addition, it is difficult to reproduce the state in which the conductive layer of the conductive particles is peeled off and the surface of the resin core is exposed under the above-described connection conditions. Therefore, the conductive particles in which one part of the conductive layer is peeled off and the surface of the resin core is exposed are prepared in advance, and the evaluation is performed. A connector sample in which the IC and the evaluation glass substrate were connected via an anisotropic conductive film in which the conductive particles were blended was used for the visibility evaluation. Furthermore, the connection conditions were the same (170 ° C, 60 MPa, 5 sec).

In the visibility evaluation, the number of conductive particles captured by the bumps of the IC for evaluation is counted in advance, and the ratio of the conductive particles exposed on the surface of the resin core which is visually recognized by an optical microscope at a magnification of 50 times is 90% or more. ◎ (optimal), the ratio of the conductive particles exposed on the surface of the resin core which is visible at a magnification of 50 times is 50% or more and less than 90%, and is set to ○ (good), and the magnification is 50 times. When the ratio of the conductive particles exposed on the surface of the resin core is 10% or more and less than 50%, it is set to Δ (normal), and the ratio of the conductive particles exposed on the surface of the resin core which is visible at a magnification of 50 times is not reached. The case of 10% is set to × (bad).

[Example 1]

In the first embodiment, 2 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and emulsified polymerization was carried out to prepare acrylic resin particles. The initial on-resistance of the bonded body sample of Example 1 was 1.2 Ω, and the on-resistance after the reliability test was 2.5 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was Δ (normal).

[Example 2]

In the second embodiment, 8 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and emulsified polymerization was carried out to prepare acrylic resin particles. The initial on-resistance of the bonded body sample of Example 2 was 1.7 Ω, and the on-resistance after the reliability test was 3.3 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was ○ (good).

[Example 3]

In Example 3, 15 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and emulsified polymerization was carried out to prepare acrylic resin particles. The initial on-resistance of the bonded body sample of Example 3 was 2.2 Ω, and the on-resistance after the reliability test was 4.8 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was ○ (good).

[Example 4]

In Example 4, 23 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and emulsified polymerization was carried out to prepare acrylic resin particles. The initial on-resistance of the sample of the connector of Example 4 was 3.2 Ω, and the on-resistance after the reliability test was 9.3 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was ○ (good).

[Example 5]

In Example 5, 30 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and an acrylic resin particle was produced by emulsion polymerization. The initial on-resistance of the sample of the connector of Example 5 was 4.3 Ω, and the on-resistance after the reliability test was 17.5 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was ○ (good).

[Comparative Example 1]

In Comparative Example 1, a coloring agent was not added to the above amine ester compound to prepare acrylic resin particles. The initial on-resistance of the sample of the connector of Comparative Example 1 was 1.2 Ω, and the on-resistance after the reliability test was 2.1 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was × (bad).

[Comparative Example 2]

In Comparative Example 2, 1 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a colorant in the above amine ester compound, and propylene was produced by emulsion polymerization. Acid resin particles. The initial on-resistance of the connector sample of Comparative Example 2 was 1.1 Ω, and the on-resistance after the reliability test was 2.2 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was × (bad).

[Comparative Example 3]

In Comparative Example 3, 38 vol% of titanium oxide (TIPAQUE R-820 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed as a coloring agent in the above amine ester compound, and an acrylic resin particle was produced by emulsion polymerization. The initial on-resistance of the connector sample of Comparative Example 3 was 6.9 Ω, and the on-resistance after the reliability test was 21.9 Ω, and the visibility of the conductive particles from which the conductive layer was peeled off was ○ (good).

As shown in Table 1, in the examples 1 to 5, the visibility of the conductive particles was high, and it was evaluated as Δ (normal) or more. Since the sample of the examples of the first to fifth embodiments is formed by using a conductive adhesive film in which conductive particles colored by adding an appropriate amount of coloring agent are blended, the visibility and the connectivity can be ensured.

In Comparative Example 1, the resin core of the conductive particles was not colored, and the amount of the colorant added in Comparative Example 2 was small. Therefore, the conductive particles which were separated by the IC bump as the background conductive layer were inferior in visibility. The inspection steps are complicated.

Further, in Comparative Example 3, since the amount of the coloring agent added is too large, the resin core becomes hard, and the followability of the expansion and contraction of the distance between the IC bump and the ITO film is deteriorated, so that the on-resistance is large and the connection reliability is lacking.

1‧‧‧ anisotropic conductive film

10‧‧‧LCD panel

11‧‧‧Transparent substrate

12‧‧‧Transparent substrate

12a‧‧‧Edge

13‧‧‧ Sealing material

14‧‧‧LCD

15‧‧‧ Panel display

16‧‧‧Transparent electrode

17‧‧‧Transparent electrode

18‧‧‧LCD driver IC

27‧‧‧Installation Department

28‧‧‧Alignment film

29a‧‧‧Polar plate

29b‧‧‧Polar plate

33‧‧‧Hot head

Claims (12)

A connection method for connecting a transparent electrode formed on a transparent substrate and a connection terminal of an electronic component by an anisotropic conductive adhesive, and sandwiched between the transparent electrode and the connection terminal The conductive particles are formed by coating a resin core with a conductive layer, and the resin core is colored in a color different from the connection terminal, and the color of the resin core is detected and captured on the transparent electrode and the resin core Conductive particles exposed on the surface. The method for inspecting a connector according to the first aspect of the invention, wherein the resin core is colored by a filler which is complementary to a color (opposite color) to a surface of the connection terminal. The method for inspecting a connector according to the second aspect of the invention, wherein the resin core is not disposed with the connection terminal when the color of the surface of the connection terminal is placed at a center of one of the regions in which the hue ring is equally divided. The filler of the color of the area adjacent to the area to which the color of the surface belongs is colored. The method for inspecting a connector according to any one of claims 1 to 3, wherein the resin core is obtained by polymerizing an acrylic monomer. The method for inspecting a connector according to any one of claims 1 to 3, wherein the size of the filler is less than 30% of the particle diameter of the conductive particles. The method for inspecting a linker according to any one of claims 1 to 3, wherein the blending amount of the above filler is less than 30 vol%. The method for inspecting a connector according to any one of claims 1 to 3, wherein the filler is spherical. The method for inspecting a linker according to any one of claims 1 to 3, wherein 90% of the total size of the filler is within ±20% of the average diameter of the filler. The method for inspecting a connector according to any one of claims 1 to 3, wherein the entire surface of the resin core is exposed. A connector is obtained by connecting an anisotropic conductive adhesive to a connection terminal of a transparent electrode and an electronic component formed on a transparent substrate, and is sandwiched between the transparent electrode and the connection terminal. The resin core is coated with a conductive layer, and the resin core is colored differently from the connection terminal, and the conductive particles trapped on the transparent electrode can be visually recognized by the resin core. The surface of the core is exposed. An electroconductive particle which is contained in an adhesive which is formed by anisotropic conductive connection between a transparent electrode formed on a transparent substrate and a connection terminal of an electronic component, and has a resin core and a conductive layer covering a surface of the resin core The resin core is colored in a color different from the connection terminal, and the surface of the resin core can be visually recognized by the color of the resin core. An anisotropic conductive adhesive comprising conductive particles in a binder resin, and connecting a transparent electrode formed on a transparent substrate to a connection terminal of an electronic component, wherein the conductive particles have a resin core and a coating a conductive layer on the surface of the above resin core, The resin core is colored in a color different from the connection terminal, and the surface of the resin core can be visually recognized by the color of the resin core.