JP2013247063A - Conductive pattern forming substrate and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive pattern forming substrate which has low electrical resistance and high reliability in electrical connection, and a method of manufacturing the same.SOLUTION: A conductive pattern forming substrate 1 including an insulating base material 2 and a conductive pattern 4 provided on an outer surface of the insulating base material 2 is characterized in that the conductive pattern 4 includes: a fine particle layer 5 which is held on the insulating base material 2 in a state where a plurality of silver nanowires NW are dispersed in a light transmissive resin; and a connection part 8 which is provided at a part of the fine particle layer 5 and in which the silver nanowires NW are electrically and physically connected to each other.

Description

  The present invention relates to a conductive pattern forming substrate and a manufacturing method thereof.

  Conventionally, as an example of a conductive pattern formed on a substrate, a conductive pattern having ITO (indium tin oxide) or conductive nanowires is known. These conductive patterns can constitute a light-transmitting conductive pattern, and are employed for transparent electrodes arranged on the screen of the touch panel.

  For example, Patent Document 1 discloses a conductive pattern forming substrate (conductive nanofiber sheet) in which a conductive pattern and an insulating pattern insulated from the conductive pattern are formed on a base material (base sheet). In the conductive pattern described in Patent Document 1, conduction is ensured by bringing the conductive nanowires into contact with each other.

JP 2010-140859 A

  However, in the technique disclosed in Patent Document 1, although the conductive nanowires are held in contact with each other, the contact resistance is high because they are simply in contact with each other, and the conductive nanowires are separated and electrically There is a possibility of insulation.

  This invention is made | formed in view of the situation mentioned above, The objective is to provide a conductive pattern formation board | substrate with low electrical resistance and high reliability of electrical connection, and its manufacturing method.

In order to solve the above problems, the present invention proposes the following means.
The conductive pattern forming substrate of the present invention is a conductive pattern forming substrate comprising an insulating base material and a conductive pattern provided on the outer surface of the insulating base material, wherein the conductive pattern is on the insulating base material, A fine particle layer held in a state where a plurality of fine metal particles are in contact with each other, a conductive layer fixed in a state where the fine particle layer is held in a light-transmitting resin, and a part of the fine particle layer provided above A conductive pattern forming substrate having a connection portion in which fine metal particles are welded and electrically and physically connected.

  The fine metal particles may be conductive fine fibers, and the conductive fine fibers may be dispersed so as to form a two-dimensional network.

  The conductive pattern may be provided with an electrode having a longitudinal axis or a wiring having a longitudinal axis, and the connecting portion may be arranged along the longitudinal axis.

  Further, the method for producing a conductive pattern forming substrate of the present invention comprises forming a fine particle layer in which a plurality of fine metal particles are dispersed in a light-transmitting resin on an insulating substrate, and the fine metal particles in a part of the fine particle layer. The insulating pattern and the conductive pattern are formed by removing and the heating means for heating the fine metal particles is applied to a part of the part that becomes the conductive pattern in the fine particle layer. It is a manufacturing method of the conductive pattern formation board | substrate characterized by integrating a contact location.

Further, the conductive pattern may be formed after the heating means is operated.
The method for manufacturing a conductive pattern forming substrate, wherein the heating means is irradiation of laser light to the fine particle layer, and the adjacent minute metal particles are welded to each other at a portion irradiated with the laser light.

  The laser beam irradiation may be pulsed laser irradiation.

  Further, the step of connecting the adjacent minute metal particles by applying the heating means is performed in a region that becomes the conductive pattern forming substrate in a long base material that can cut out the plurality of insulating base materials. May be performed.

  Further, an electrode having a longitudinal axis or a wiring having a longitudinal axis may be formed as the conductive pattern, and the heating means may be caused to act linearly along the longitudinal axis of the electrode or the longitudinal axis of the wiring.

  Further, the heating means may be operated a plurality of times along the longitudinal axis of the electrode or the longitudinal axis of the wiring.

  Further, the heating means may be applied linearly to a plurality of locations that are parallel to the longitudinal axis of the electrode or the longitudinal axis of the wiring and are spaced apart from each other.

  According to the conductive pattern forming substrate and the manufacturing method thereof of the present invention, the electrical resistance in the conductive pattern is low, and the reliability of electrical connection is high.

It is a typical top view of the conductive pattern formation board of one embodiment of the present invention. (A) is sectional drawing in the AA of FIG. 1, (B) is a typical top view of (A). It is a flowchart which shows the manufacturing method of the same conductive pattern formation board | substrate. It is a figure for demonstrating the manufacturing process of the same conductive pattern formation board | substrate. It is a figure for demonstrating the manufacturing process of the same conductive pattern formation board | substrate. FIG. 5 is a schematic X arrow view of FIG. 4. It is a typical top view which shows the structure of the modification of the same conductive pattern formation board | substrate.

The conductive pattern formation board | substrate 1 of one Embodiment of this invention and its manufacturing method are demonstrated.
First, the configuration of the conductive pattern forming substrate 1 of the present embodiment will be described. FIG. 1 is a schematic plan view of a conductive pattern forming substrate 1 of the present embodiment. 2A is a cross-sectional view taken along line AA in FIG. FIG. 2B is a schematic plan view of FIG.

As shown in FIGS. 1 and 2A, the conductive pattern forming substrate 1 includes an insulating base 2 and a transparent conductive layer 3 provided on the outer surface of the insulating base 2.
The insulating substrate 2 is a thin plate, sheet, film, or film-like member having insulating properties such as resin or glass. Moreover, in this embodiment, the insulating base material 2 has a light transmittance.
Moreover, in this embodiment, the insulating base material 2 has flexibility. Specifically, as the material of the insulating base material 2, a resin such as a thermoplastic resin or a thermosetting resin can be suitably used. Specific materials for the insulating substrate 2 include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, cyclic polyolefin, polysulfone, polyethersulfone, polyacrylic resin, cycloolefin polymer, and light transmittance. Other resin materials can be used.

  The transparent conductive layer 3 has a conductive pattern 4 and an insulating pattern 9 and an overcoat layer 10.

The conductive pattern 4 has a fine particle layer 5 and a connection portion 8.
The fine particle layer 5 is a layer held on the insulating base material 2 in a state where a plurality of fine metal particles are dispersed in a light-transmitting resin. As the fine metal particles constituting the fine particle layer 5, a highly conductive material such as particles containing gold, silver, copper, nickel or the like can be used. Moreover, the shape of the fine metal particles constituting the fine particle layer 5 can be spherical, granular, wire-like, or rod-like. In the present embodiment, conductive ultrafine fibers are employed as the fine metal particles. Specifically, examples of the conductive ultrafine fiber include metal nanowires. For example, the fine particle layer 5 is configured by fixing the silver nanowires NW to the insulating substrate 2 with an overcoat layer 10 containing a light transmissive resin.
As shown in FIGS. 2 (A) and 2 (B), the fine metal particles are dispersed in the overcoat layer 10 at a density that allows contact with each other, and there are gaps therebetween. Thereby, in the fine particle layer 5, the fine metal particles are electrically connected to each other to form a two-dimensional network extending in the surface direction of the insulating substrate 2. Further, the fine metal particles constituting the fine particle layer 5 are formed so that the dimension in the thickness direction of the insulating substrate 2 is thin, and the fine particle layer 5 as a whole has light transmittance. In addition to the spread in the surface direction of the insulating base material 2, the network of fine metal particles in the fine particle layer 5 can be considered to be three-dimensional in consideration of the spread in the thickness direction of the insulating base material 2.
The fine particle layer 5 has a pattern of a predetermined shape so as to be an electrode, a wiring or the like in the transparent conductive layer 3. For example, in the present embodiment, the fine particle layer 5 has a pattern shape including a strip-like electrode 6 having a longitudinal axis and extending in the longitudinal axis direction, and a lead wiring 7 connected to the electrode 6.
The fine particle layer 5 does not necessarily have a pattern in which electricity flows. For example, a pattern such as a shield configured as an electrically floating state may be included in the fine particle layer 5.

  The connection part 8 is provided in a part of the fine particle layer 5 and is configured by electrically and physically connecting fine metal particles (in this embodiment, silver nanowires NW). The physical connection between the fine metal particles in the connecting portion 8 is formed by welding the fine metal particles. In the present embodiment, the connection portion 8 is formed in the electrode 6 on a line extending in the longitudinal axis direction of the electrode 6. For example, the connection portion 8 is formed in a single line with respect to each electrode 6.

  The insulating pattern 9 is a portion other than the conductive pattern 4 in the transparent conductive layer 3. In the present embodiment, in the insulating pattern 9, a minute hole 9 a remaining after the minute metal particles are removed is formed in the overcoat layer 10.

  The overcoat layer 10 is a light-transmitting layer provided for the purpose of enhancing the adhesion between the fine metal particles and the insulating substrate 2. The thickness of the overcoat layer 10 is preferably such a thickness that a part of the fine metal particles (silver nanowires NW in the present embodiment) on the insulating base material 2 is buried in the overcoat layer 10. A part of the fine metal particles is exposed on the outer surface of the overcoat layer 10.

  Next, the manufacturing method of the conductive pattern formation board | substrate 1 is demonstrated. FIG. 3 is a flowchart showing a method for manufacturing the conductive pattern forming substrate 1. 4 and 5 are diagrams for explaining a manufacturing process of the conductive pattern forming substrate 1. FIG. 6 is a schematic view taken in the direction of arrow X in FIG. 4 and is an enlarged plan view showing the fine particle layer 5.

First, a layered conductive resin layer 3a in which fine metal particles are dispersed in a light-transmitting resin is formed on the outer surface of the insulating substrate 2 (step S1 shown in FIG. 3).
In step S1, first, a solution containing fine metal particles (silver nanowires NW) and a water-soluble polymer in an aqueous solvent is uniformly applied to the outer surface of the insulating substrate 2, and the aqueous system is dried by drying the solution. Remove the solvent. In step S1, as shown in FIG. 4, the solution is applied to the region of the long base material 2a from which the plurality of insulating base materials 2 can be cut out to be the conductive pattern forming substrate 1. The application of the solution to the base material 2a can be performed by appropriately selecting a known method such as printing or coating. Then, with the water-soluble polymer attached to the outer surface of the fine metal particles, the fine metal particles adhere to the outer surface of the insulating substrate 2 by the water-soluble polymer. In a state where the fine metal particles are attached to the insulating base material 2 by the water-soluble polymer, the fine metal particles are temporarily fixed to the insulating base material 2.

  Furthermore, as shown in FIG. 4, the laser L2 for welding the fine metal particles is irradiated to the fine metal particles on the insulating base material 2. The irradiation of the laser L2 for welding the fine metal particles is a heating means for heating the fine metal particles in the present embodiment. The irradiation position of the laser L2 is set to a position where it is desired to lower the electric resistance as compared with the case where the minute metal particles are simply in contact with each other. For example, in the present embodiment, the laser L2 is irradiated to a part of the region that becomes the conductive pattern 4.

Specifically, in the present embodiment, the laser L2 for welding the fine metal particles is irradiated for the purpose of forming the connection portion 8. In the present embodiment, the electrode is formed in the region to be the electrode 6. 6 is irradiated linearly in the longitudinal direction. When the laser beam L2 is applied to the fine metal particles, the fine metal particles are heated and welded to the adjacent fine metal particles. In FIG. 6, a welded portion in the fine metal particle (metal nanowire NW) is indicated by reference numeral 8 a. The laser L2 for welding the fine metal particles preferably has a lower output or energy density than a laser L1 described later for laser etching. In this embodiment, the irradiation of the laser L2 for welding the fine metal particles is a pulsed laser irradiation.
Thereby, the area | region used as the conductive pattern 4 on the insulating base material 2 was electrically and physically connected with the fine particle layer 5 which is conducting in a state where the fine metal particles are in contact with each other. A structure having a connection portion 8 is obtained.

  Note that the irradiation of the laser L2 for welding the fine metal particles may be before or after the irradiation of the laser L1 for laser etching in step S2, which will be described later, or the laser L1 for laser etching. It may be simultaneous or alternating with irradiation.

Subsequently, in the state where the fine metal particles are attached to the base material, a fluid-like light-transmitting resin as a material for the overcoat layer 10 is applied to the outer surface of the insulating base material 2. The fluid-like light-transmitting resin enters the gaps between the fine metal particles and comes into contact with the fine metal particles and the outer surface of the insulating substrate 2. The fluid-like light transmissive resin may be in contact with the insulating substrate 2 through a water-soluble polymer. In this state, the light transmissive resin is cured in a fluid form. Thereby, the overcoat layer 10 that fixes the fine metal particles and the insulating base material 2 is formed. At this stage, the conductive resin layer 3a having the same electrical conductivity as the solid metal pattern is formed by the fine metal particles, the trace amount of the water-soluble polymer, and the overcoat layer 10. In the conductive resin layer 3a, the fine metal particles are electrically connected by being in contact with each other.
Step S1 is complete | finished now and it progresses to step S2.

Step S2 is a step of forming the conductive pattern 4 and the insulating pattern 9 on the conductive resin layer 3a.
In step S2, after the overcoat layer 10 is formed, the fine metal particles in the region to be the insulating pattern 9 are removed by laser etching with laser L1 irradiation. When the fine metal particles dispersed in the overcoat layer 10 are irradiated with the laser L1, the fine metal particles evaporate, and the fine holes 9a remain in the overcoat layer 10 instead of the fine metal particles. A portion where the minute metal particles are removed by laser etching is the insulating pattern 9, and a portion where the minute metal particles are left is the conductive pattern 4.

If the laser L2 for welding the fine metal particles is not irradiated in step S1, the laser L2 for welding the fine metal particles is irradiated after the formation of the conductive pattern 4 in step S2. Also good. Further, after the irradiation of the laser L2 for welding the fine metal particles in the above-described step S1, further laser irradiation for welding the fine metal particles can be performed.
Further, the laser etching using the laser L1 for removing the fine metal particles may be performed before the overcoat layer 10 is formed. When laser etching is performed before the overcoat layer 10 is formed, the gap formed by the evaporation of the fine metal particles is filled with a fluid of the light-transmitting resin constituting the overcoat layer 10, The above-mentioned minute hole 9a is not formed.
This ends step S2.
After step S2, a protective layer may be laminated on the conductive pattern 4 and the insulating pattern 9 with resin, glass, or the like as necessary (step S3). The protective layer can be provided by appropriately selecting an insulating and light-transmitting material and attaching it with an adhesive or a pressure-sensitive adhesive.

Next, the operation of the conductive pattern forming substrate 1 will be described.
Conventionally, in a light-transmitting conductive layer having fine metal particles, the content of the fine metal particles relative to the light-transmitting resin is set so that the fine metal particles and the like have a density at which they can contact each other.
For this reason, the conduction | electrical_connection state of minute metal particles changes with contact states of minute metal particles. That is, when the density of the fine metal particles is high, there are many contacts serving as a conduction path, and when the density of the fine metal particles is low, there are few contacts serving as a conduction path. In addition, when a layer containing fine metal particles is laminated on a flexible base material, when the base material is bent, the contact state between the fine metal particles changes, and the contact resistance fluctuates or poor conduction occurs. May occur.
As a result, in the conventional configuration, the setting of the density of the fine metal particles is complicated, and there is a possibility that unevenness of electric resistance may occur due to the variation in the density of the fine metal particles.

On the other hand, in the conductive pattern forming substrate 1 of the present embodiment, since the physical connection between the fine metal particles is performed by the laser L2, the conduction state between the fine metal particles is made more reliable. Can do.
And since the minute metal particles are connected in the connection part 8, compared with the case where the minute metal particles are simply in contact with each other, the electrical resistance in the conductive pattern 4 is low, and the reliability of the electrical connection is high.
In addition, the conductive pattern forming substrate 1 of the present embodiment can be suitably applied to a transparent wiring board having optical transparency such as a capacitive touch panel. In this case, the connection portion 8 to which fine metal particles are welded. The electrical resistance can be lowered in the longitudinal direction of the elongated electrode. Furthermore, since the connection portion 8 can be formed by irradiation with the laser L2, the time required for processing can be reduced as compared with the case where the overall electrical resistance of the conductive pattern 4 is lowered, and the conductive pattern forming substrate 1 Deterioration of optical characteristics can be kept low.

(Modification 1)
Next, a modification of the method for manufacturing the conductive pattern forming substrate 1 of the present embodiment will be described.
This modification is different in that the same part is irradiated with a pulsed laser a plurality of times. By performing laser irradiation a plurality of times, welding between the fine metal particles can be made more reliable.

(Modification 2)
Next, another modification of the method for manufacturing the conductive pattern forming substrate 1 of the present embodiment will be described. FIG. 7 is a schematic plan view showing a configuration of a modified example of the conductive pattern forming substrate.
This modification is different from the above-described embodiment in that a plurality of connection portions 8 are formed on one electrode 6 at positions that are parallel to each other and separated from each other.
In the conductive pattern forming substrate 1 manufactured by the manufacturing method of this modification, a plurality of (for example, two as shown in FIG. 7) connecting portions 8 with respect to one electrode 6 are provided along the longitudinal axis of the electrode 6. They are formed parallel to each other.
According to the manufacturing method of the present modification, the number of welded portions between the fine metal particles can be increased as compared with the above-described embodiment, so that the electrical connection can be made more reliable and the electrical resistance can be kept low.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment and the modification thereof, an example in which the connection portion is formed with respect to the electrode has been described. However, the connection portion may be appropriately formed in a region included in the conductive pattern without being limited to the electrode. For example, when the connection portion is formed on the wiring, the certainty of conduction between the fine metal particles is increased, and sufficient conductivity can be obtained even if the line width is reduced.

Further, in the above-described embodiment, the electrode is described and illustrated as an elongated strip shape, but the shape of the electrode is not limited to this. For example, the electrodes may be arranged such that a plurality of rectangular electrodes are arranged side by side with their diagonals connected to each other, or may have a non-elongated shape. The electrodes may include a first layer electrode extending in parallel with each other and a second layer electrode extending in parallel with each other in a direction intersecting with the electrode.
In addition, the constituent elements shown in the above-described embodiment and each modification can be combined as appropriate.
In addition, the design change etc. with respect to the said specific structure are not limited to the said matter.

DESCRIPTION OF SYMBOLS 1 Conductive pattern formation board | substrate 2 Insulation base material 3 Transparent conductive layer 4 Conductive pattern 5 Fine particle layer 6 Electrode 7 Lead-out wiring 8 Connection part 9 Insulation pattern 10 Overcoat layer

Claims (11)

A conductive pattern forming substrate comprising an insulating substrate and a conductive pattern provided on the outer surface of the insulating substrate,
The conductive pattern is
On the insulating substrate, a fine particle layer held in a state where a plurality of fine metal particles are in contact with each other;
A conductive layer fixed in a state where the fine particle layer is held in a light transmissive resin;
A connection part provided in a part of the fine particle layer and electrically and physically connected to each other by welding the fine metal particles;
A conductive pattern forming substrate comprising: The conductive pattern forming substrate according to claim 1,
The fine metal particles are conductive ultrafine fibers,
The conductive pattern forming substrate, wherein the conductive ultrafine fibers are dispersed so as to form a two-dimensional network. The conductive pattern forming substrate according to claim 1 or 2,
In the conductive pattern, an electrode having a longitudinal axis or a wiring having a longitudinal axis is formed,
The connection part is disposed along the longitudinal axis. The conductive pattern forming substrate, wherein: A fine particle layer in which a plurality of fine metal particles are dispersed in a light-transmitting resin is formed on an insulating substrate,
Forming an insulating pattern and a conductive pattern by removing the fine metal particles in a part of the fine particle layer;
Conductive pattern formation characterized in that a heating means for heating the fine metal particles is applied to a part of the portion to be the conductive pattern in the fine particle layer to integrate the contact portions of the adjacent fine metal particles. A method for manufacturing a substrate. It is a manufacturing method of the conductive pattern formation board according to claim 4,
A method for producing a conductive pattern forming substrate, wherein the conductive pattern is formed after the heating means is applied. It is a manufacturing method of the conductive pattern formation board according to claim 4 or 5,
The method for manufacturing a conductive pattern forming substrate, wherein the heating means is irradiation of laser light to the fine particle layer, and the adjacent minute metal particles are welded to each other at a portion irradiated with the laser light. It is a manufacturing method of the conductive pattern formation board according to claim 6,
The method of manufacturing a conductive pattern forming substrate, wherein the laser beam irradiation is pulsed laser irradiation. It is a manufacturing method of the conductive pattern formation board according to any one of claims 4 to 7,
The step of connecting the adjacent minute metal particles by applying the heating means is performed in a region to be the conductive pattern forming substrate in a long base material that can cut out the plurality of insulating base materials. A method for producing a conductive pattern-formed substrate. It is a manufacturing method of the conductive pattern formation board according to any one of claims 4 to 8,
As the conductive pattern, an electrode having a longitudinal axis or a wiring having a longitudinal axis is formed,
The method for manufacturing a conductive pattern forming substrate, wherein the heating means is caused to act linearly along the longitudinal axis of the electrode or the longitudinal axis of the wiring. It is a manufacturing method of the conductive pattern formation board according to claim 9,
A method for manufacturing a conductive pattern forming substrate, wherein the heating means is applied a plurality of times along a longitudinal axis of the electrode or a longitudinal axis of the wiring. It is a manufacturing method of the conductive pattern formation board according to claim 9 or 10,
A method of manufacturing a conductive pattern forming substrate, wherein the heating means is applied linearly to a plurality of locations parallel to the longitudinal axis of the electrode or the longitudinal axis of the wiring and spaced apart from each other.

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