JP2013222590A - Conductive pattern formation substrate and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive pattern formation substrate capable of reducing pattern visualization, and a manufacturing method thereof.SOLUTION: A conductive pattern formation substrate comprises: a base material 2 having light permeability; a transparent conductive layer 3 provided on the base material 2; a protective layer 8 provided on the transparent conductive layer 3; and a double-side adhesive tape 9 for fixing the protective layer 8 to the transparent conductive layer 3. The transparent conductive layer 3 has: a conductive pattern 4 in which minute metal particles are dispersed in light permeable resin; and an insulation pattern 5 in which the minute metal particles are removed from a layer including the minute metal particles and the light permeable resin, and a minute hole 5a corresponding to a region occupied by the minute metal particles before formation is bored. The double-side adhesive tape 9 fixes the protective layer 8 to the transparent conductive layer 3 while gas exists in the minute hole 5a in the insulation pattern 5.

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 silver 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).
The conductive pattern described in Patent Document 1 includes conductive nanowires. An insulating pattern is formed by burning the conductive nanowires with a laser or corroding the conductive nanowires by etching using acid or alkali. The insulating pattern is in a state in which part of the conductive nanowire remains so that the difference in light transmittance is 10% or less and the difference in haze value is 5% or less with respect to the conductive pattern. .

JP 2010-140859 A

  However, the conductive nanofiber sheet described in Patent Document 1 has a problem in that the pattern may be visible because the boundary between the conductive pattern and the insulating pattern is still clear.

  This invention is made | formed in view of the situation mentioned above, The objective is to provide the conductive pattern formation board | substrate which can reduce pattern appearance, 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 includes a light-transmitting base material, a transparent conductive layer provided on the base material, a protective layer provided on the transparent conductive layer, and the transparent conductive layer. Fixing means for fixing a protective layer, wherein the transparent conductive layer is a layer containing a conductive pattern in which fine metal particles are dispersed in a light-transmitting resin, and the fine metal particles and the light-transmitting resin. The fine metal particles are removed from the insulating pattern, and a gap corresponding to a region occupied by the fine metal particles before the formation is formed, and the fixing means includes the insulating pattern in the insulating pattern. The conductive pattern forming substrate is characterized in that the protective layer is fixed to the transparent conductive layer in a state where a gas exists in a gap.

  The fixing means may connect the transparent conductive layer and the protective layer in a state where the transparent conductive layer and the protective layer are separated from each other in the thickness direction of the base material.

  Moreover, the said protective layer may have a hard light transmissive panel, and the said fixing means may have a soft transparent resin film which touches both the said transparent conductive layer and the said protective layer.

  Further, the fixing means is made of a cured material of a fluid sandwiched between the transparent conductive layer and the protective layer, and the cured material of the fluid encloses the gap in the insulating pattern with air. You may seal in the state made.

  The transparent conductive layer may be provided on both surfaces of the base material, and the fixing means and the protective layer may be provided on only one of the transparent conductive layers provided on both surfaces of the base material. Good.

  The transparent conductive layer is provided only on one surface in the thickness direction of the substrate with respect to the substrate, and is different from the substrate on the other surface in the thickness direction of the substrate. A second substrate may be provided, and the second substrate may be provided with a second transparent conductive layer different from the transparent conductive layer.

  The fixing means is in contact with the second transparent conductive layer and the first base material, and the first base material is fixed to the second transparent conductive layer. The first base material is the second transparent conductive layer. The protective layer for the conductive layer may be used.

  According to the conductive pattern forming substrate and the manufacturing method thereof of the present invention, pattern appearance can be reduced.

It is a typical top view which shows the conductive pattern formation board | substrate of one Embodiment of this invention. It is sectional drawing in the AA of FIG. FIG. 3 is an enlarged view of FIG. 2. It is a flowchart which shows the manufacturing method of the conductive pattern formation board | substrate of the embodiment. It is a figure which shows the manufacturing process of the same conductive pattern formation board | substrate. It is a figure which shows the manufacturing process of the conductive pattern formation board | substrate. It is a figure which shows the manufacturing process of the same conductive pattern formation board | substrate. It is a figure which shows the manufacturing process of the same conductive pattern formation board | substrate. It is a figure which shows the manufacturing process of the same conductive pattern formation board | substrate. It is a figure which shows the structure of the modification of the embodiment. It is a figure which shows the other modification of the embodiment. It is a figure which shows the other modification of the embodiment.

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 will be described. FIG. 1 is a schematic plan view showing a conductive pattern forming substrate of this embodiment. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is an enlarged view of FIG.
As shown in FIG. 1 thru | or FIG. 3, the conductive pattern formation board | substrate 1 of this embodiment has the layered structure on which the base material 2, the transparent conductive layer 3, and the protective layer 8 were piled up in this order. The transparent conductive layer 3 and the protective layer 8 are provided with a gap. Although details are not shown, in the present embodiment, the wiring 7 is formed on the transparent conductive layer 3.

  The substrate 2 is a plate-like, sheet-like, film-like, or film-like insulating member. The base material 2 has light transmittance. As a material of the base material 2, a resin such as a thermoplastic resin or a thermosetting resin can be suitably used. Specific materials for the 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 light transmittance of the substrate 2 is preferably 85% or more. Moreover, it is preferable that the base material 2 is colorless and transparent. In addition, the base material 2 has a light transmittance and may be colored.
It is preferable that the thickness of the base material 2 is 0.05 mm or more and 0.2 mm or less. Moreover, the thickness of the base material 2 is more preferably 0.1 mm or more and 0.15 mm or less. If the thickness of the substrate 2 is 0.05 mm or more, it is easy to form a structure such as the conductive pattern 4 on the substrate 2. Moreover, when the thickness of the base material 2 is 0.2 mm or less, the light transmittance in the thickness direction of the base material 2 is excellent, and the conductive pattern forming substrate 1 can be made thin.
Furthermore, the base material 2 may have flexibility.

  The transparent conductive layer 3 includes a conductive pattern 4 and an insulating pattern 5 and an overcoat layer 6.

The conductive pattern 4 is provided with a pattern shape in a state in which the positional relationship is fixed with respect to the base material 2 including fine metal particles. As the fine metal particles constituting the conductive pattern 4, particles containing gold, silver, copper, nickel or the like can be employed. Further, the shape of the fine metal particles constituting the conductive pattern 4 can be spherical, granular, wire-shaped, and rod-shaped. In the present embodiment, the conductive pattern 4 is configured by fixing the silver nanowire NW to the base material 2 by the overcoat layer 6. The fine metal particles contained in the conductive pattern 4 conduct when in contact with each other, and function as an electrode or the like. Furthermore, the conductive pattern 4 has light transmittance due to a gap between the fine metal particles.
The conductive pattern 4 is not necessarily a pattern through which electricity flows. For example, a pattern such as a shield configured as an electrically floating state may be included in the conductive pattern 4.

  The insulating pattern 5 is a portion other than the conductive pattern 4 in the transparent conductive layer 3. As shown in FIG. 3, in the present embodiment, in the insulating pattern 5, the minute holes 5 a remaining after the minute metal particles are removed are formed in the overcoat layer 6.

  The overcoat layer 6 is a light-transmitting layer provided for the purpose of enhancing the adhesion between the fine metal particles and the substrate 2. The thickness of the overcoat layer 6 is preferably such that a part of the fine metal particles (in this embodiment, silver nanowires NW) on the substrate 2 is buried in the overcoat layer 6. A part of the fine metal particles is exposed on the outer surface of the overcoat layer 6. The fine metal particles are in contact with the wiring 7, and the transparent conductive layer 3 and the wiring 7 are electrically connected because the fine metal particles and the wiring 7 are in contact with each other.

As a material for the overcoat layer 6, a fluid that is light transmissive and can be appropriately selected and employed as a fluid that is cured by a predetermined curing process. The predetermined curing process is, for example, heat curing, ultraviolet curing, electron beam curing, or other processes, and is appropriately selected according to the material.
That is, as the material of the overcoat layer 6, a thermoplastic resin, an ultraviolet curable resin, an adhesive, or the like can be employed. Examples of the thermoplastic resin that can be suitably used as the material for the overcoat layer 6 include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polycarbonate, polyacrylic resin, and polymethyl methacrylate. Examples of the curable resin that is cured by being irradiated with ultraviolet rays, heat, electron beams, or radiation include ether polyurethane, ester polyurethane, polyurethane acrylate, epoxy resin, and polyimide resin. .

  When metal nanowires such as silver nanowires are employed as the fine metal particles, the thickness of the overcoat layer 6 is preferably 50 nm or more and 300 nm or less. The thickness of the overcoat layer 6 in the present embodiment is a thickness when measured using the outer surface of the substrate 2 as a base point. The overcoat layer 6 is also disposed between the fine metal particles so as to fill at least a part of the gap between the fine metal particles constituting the conductive pattern 4.

  The wiring 7 is formed on the overcoat layer 6 by fixing a metal-containing paste or by forming a metal layer by vapor deposition or the like. In the present embodiment, the wiring 7 is formed in a pattern with a paste containing silver particles, and then the paste is fixed, whereby the silver particles are coupled to each other to be in a conductive state.

  The protective layer 8 is formed of a light-transmitting resin, glass, or the like, and is fixed to the transparent conductive layer 3 by a double-sided adhesive tape 9 (fixing means) in which an adhesive is provided on both sides of a soft transparent resin film. ing. The double-sided pressure-sensitive adhesive tape 9 is provided in a substantially rectangular shape along the periphery of the protective layer 8 and the transparent conductive layer 3. Thus, in the inner region surrounded by the double-sided adhesive tape 9 when viewed from the thickness direction of the conductive pattern forming substrate 1, the protective layer 8 is separated from the transparent conductive layer 3 by the thickness of the double-sided adhesive tape 9. ing.

  Next, the manufacturing method of the conductive pattern formation board | substrate 1 is demonstrated. FIG. 4 is a flowchart showing the method for manufacturing the conductive pattern forming substrate of this embodiment. 5 to 9 are diagrams showing a manufacturing process of the conductive pattern formation substrate.

First, the light-transmitting conductive pattern 4 having a pattern shape is formed on the outer surface of the light-transmitting substrate 2 (step S1 shown in FIG. 4).
In the step of forming the conductive pattern 4, first, as shown in FIG. 5, 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 substrate 2. Then, the aqueous solvent is removed by drying the solution. 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 substrate 2 by the water-soluble polymer. In a state where the fine metal particles are adhered to the substrate 2 by the water-soluble polymer, the fine metal particles are temporarily fixed to the substrate 2.

  Subsequently, with the fine metal particles attached to the base material 2, a fluid-like light-transmitting resin that is a material of the overcoat layer 6 is applied to the base material 2. The fluid-like light-transmitting resin enters the gaps between the fine metal particles, and can be fixed to the fine metal particles and the substrate 2. In this state, the light transmissive resin is cured in a fluid form. Thereby, as shown in FIG. 6, the overcoat layer 6 which fixes a fine metal particle and the base material 2 is formed. At this stage, a conductive resin layer having the same electrical conductivity as the solid metal pattern is formed by the fine metal particles, a small amount of the water-soluble polymer, and the overcoat layer 6.

After the overcoat layer 6 is formed, the fine metal particles in the region to be the insulating pattern 5 are removed by laser etching with laser L irradiation, as shown in FIG. When the fine metal particles dispersed in the overcoat layer 6 are irradiated with laser light, the fine metal particles evaporate, and in the overcoat layer 6, minute holes 5a remain instead of the fine metal particles. A portion where the minute metal particles are removed by laser etching is the insulating pattern 5, and a portion where the minute metal particles are left is the conductive pattern 4.
Thereby, the transparent conductive layer 3 having the conductive pattern 4 and the insulating pattern 5 is formed from the conductive resin layer.
Step S1 is complete | finished now and it progresses to step S2.

Step S <b> 2 is a step of forming the wiring 7.
In step S2, as shown in FIG. 8, the wiring 7 having a predetermined pattern shape is formed by screen printing. In the present embodiment, the wiring 7 is formed by screen printing a paste containing metal particles in a pattern shape and then fixing.
Step S2 is complete | finished now and it progresses to step S3.

Step S3 is a step of forming the protective layer 8.
In step S <b> 3, as shown in FIG. 9, one adhesive surface of the double-sided adhesive tape 9 is affixed to the peripheral edge of the transparent conductive layer 3. Further, the protective layer 8 is attached so that the other adhesive surface of the double-sided adhesive tape 9 is in contact with the peripheral edge of the protective layer 8. Note that step S3 may be performed under atmospheric pressure conditions or under a pressure reduced from atmospheric pressure (for example, in a vacuumed chamber).
This ends step S3.
Through the above steps S1 to S3, the conductive pattern forming substrate 1 of the present embodiment is manufactured.

Next, the operation of the conductive pattern forming substrate 1 will be described.
The fine metal particles dispersed in the overcoat layer 6 and the fine holes 5a formed in the overcoat layer 6 both have an interface that refracts or reflects light transmitted through the transparent conductive layer 3. Have. For this reason, in the state in which the minute holes 5a remain as cavities, the light transmission characteristics between the conductive pattern 4 and the insulating pattern 5 often do not have a significant difference that leads to the pattern appearance.

  However, when an adhesive or other fluid enters the minute hole 5a, the difference in light transmission characteristics between the conductive pattern 4 and the insulating pattern 5 increases, and the possibility of leading to the pattern appearance increases. For example, when the protective layer 8 is directly attached to the transparent conductive layer 3 using an adhesive, a part of the adhesive enters the minute hole 5a in the insulating pattern 5, and the insulating pattern 5 and the conductive pattern 4 There may be a difference in the light transmission characteristics. Further, for example, when the adhesive for adhering the protective layer 8 and the light-transmitting resin constituting the insulating pattern 5 are optically similar materials, minute holes 5a are formed in the insulating pattern 5. In some cases, the optical properties may be similar to those that are not.

On the other hand, in the conductive pattern forming substrate 1 of the present embodiment, the protective layer 8 and the transparent conductive layer 3 are connected only at the part where the double-sided adhesive tape 9 is in contact, and at the other part, the double-sided adhesive tape 9. Are separated by the thickness of. For this reason, the inside of the minute hole 5a formed by removing minute metal particles in the transparent conductive layer 3 is a gap in which air exists. Therefore, even in the state in which the protective layer 8 is provided, the light transmission characteristics between the conductive pattern 4 and the insulating pattern 5 do not change, and a significant difference that leads to the pattern appearance does not newly occur. As a result, the interface between the conductive pattern 4 and the insulating pattern 5 is less visible to the user of the conductive pattern forming substrate 1. That is, in the conductive pattern forming substrate 1 of the present embodiment, the pattern appearance can be reduced.
Moreover, since the double-sided adhesive tape 9 is provided in the substantially rectangular shape along the periphery of the protective layer 8 and the transparent conductive layer 3, when using the center part of the conductive pattern formation board | substrate 1 as a display surface of a touchscreen type display apparatus. For example, the double-sided pressure-sensitive adhesive tape 9 is disposed at a position that cannot be seen by the user.

(Modification 1)
Next, a modification of this embodiment will be described. FIG. 10 is a cross-sectional view showing the configuration of this modification.
As shown in FIG. 10, the conductive pattern forming substrate 1 of this modification has a laminate film 10 instead of the double-sided adhesive tape 9 and the protective layer 8.
The laminate film 10 is a film made of a resin such as polyethylene terephthalate or polypropylene, and a heat-sensitive adhesive 11 is provided on one surface in the thickness direction. Thereby, the laminate film 10 is affixed on a sticking target object by a lamination process. Furthermore, in this modification, the laminate film 10 is transparent or light transmissive, and is attached to the entire surface of the transparent conductive layer 3.
When the laminate film 10 is attached to the transparent conductive layer 3 by laminating, the heat-sensitive adhesive 11 is softened into a fluid form and bonded to the transparent conductive layer 3. At this time, by setting the temperature so that the heat-sensitive adhesive 11 is not completely melted, the heat-sensitive adhesive 11 is cured without entering the minute holes 5 a in the insulating pattern 5, And sufficient adhesive force is obtained.
In the present modification, since the minute holes 5a in the insulating pattern 5 are sealed with the cured product of the heat-sensitive adhesive 11, the pattern appearance can be reduced as in the above-described embodiment.

(Modification 2)
Next, another modification of the present embodiment will be described.
This modification is different in that a self-adhesive film is provided instead of the laminate film 10.
The self-adhesive film is a film that does not have an adhesive and can be attached to an object to be attached due to the tackiness of the material itself. As an example of such a film, for example, a highly transparent self-adhesive film (CEF08A04) manufactured by 3M, a self-adhesive surface protective film (product name, Toretech) manufactured by Toray can be employed. .
In this modification, since the adhesive or other fluid does not enter into the minute holes 5a of the insulating pattern 5, air is easily present in the holes.

(Modification 3)
Next, another modification of the present embodiment will be described. 11 and 12 are cross-sectional views showing the configuration of this modification.
As shown in FIG. 11, the present modification is different in that two transparent conductive layers 3 are provided.
The transparent conductive layer 3 includes a first transparent conductive layer 3 a provided on one surface in the thickness direction of the substrate 2 and a second transparent conductive layer 3 b provided on the other surface in the thickness direction of the substrate 2. And have.
In the present modification, the first transparent conductive layer 3a is attached with the protective layer 8 by the double-sided pressure-sensitive adhesive tape 9 as described in the above embodiment. Further, a light-shielding frame printing portion 8a is provided on the peripheral portion of the protective layer 8, so that the double-sided adhesive tape 9 cannot be seen.
Moreover, the 2nd transparent conductive layer 3b is not provided with the double-sided adhesive tape 9 and the protective layer 8.
Even with such a configuration, the same effects as those of the above-described embodiment can be obtained. Moreover, in this modification, the electrode and wiring 7 of a two-layer structure can be formed with the 1st transparent conductive layer 3a and the 2nd transparent conductive layer 3b.

  Further, as an example of still another configuration for this modification, for example, as shown in FIG. 12, in the base material 2 (first base material 2a) described in the above-described embodiment, the transparent conductive material described in the above-described embodiment. The second substrate 2b is provided on the surface opposite to the surface on which the layer 3 (first conductive layer 3a) is formed, and the second base material 2b is electrically conductive in the same manner as the transparent conductive layer 3 described in the above embodiment. The conductive pattern formation board | substrate 1 with which the 2 transparent conductive layer 3b was formed in the 2nd base material 2b can be mentioned.

In this case, the 2nd base material 2b may be directly fixed to the 1st base material 2a via an adhesive agent or an adhesive, and the 1st group via the 2nd transparent conductive layer 3b and the double-sided adhesive tape 9 is used. It may be fixed to the material 2.
In addition, when the 2nd base material 2b is directly fixed to the 1st base material 2 via an adhesive agent or an adhesive, the protective layer similar to the protective layer 8 is separately provided in the 2nd transparent conductive layer 3b. Also good. In the state where the second base material 2b is fixed to the first base material 2 via the second transparent conductive layer 3b and the double-sided adhesive tape 9, the first base material 2 is a protective layer for the second transparent conductive layer 3b. 8 is functioning.

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 its modification, air is present in the minute holes formed in the insulating pattern, but instead of air, a gas having a composition different from air is contained in the minute holes. May be present. Further, instead of air, a transparent resin having a refractive index substantially equal to that of air may be present in the minute holes.
Further, the configuration of the above wiring is not particularly limited. For example, the wiring may be previously formed on the base material by metal vapor deposition or the like, and the above-described conductive resin layer may be formed on the base material on which the wiring is formed.
In addition, the constituent elements shown in the above-described embodiment and each modification can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 Conductive pattern formation board 2 Base material 3 Transparent conductive layer 4 Conductive pattern 5 Insulating pattern 5a Minute hole (gap)
6 Overcoat layer 7 Wiring 8 Protective layer 9 Double-sided adhesive tape (fixing means)
10 Laminate film (protective layer)
11 Heat-sensitive adhesive (fixing means)

Claims (8)

A substrate having optical transparency;
A transparent conductive layer provided on the substrate;
A protective layer provided on the transparent conductive layer;
Fixing means for fixing the protective layer to the transparent conductive layer;
With
The transparent conductive layer is
A conductive pattern in which fine metal particles are dispersed in a light-transmitting resin;
An insulating pattern formed by removing the fine metal particles from the layer containing the fine metal particles and the light-transmitting resin, and having a gap corresponding to a region occupied by the fine metal particles before formation, and
Have
The conductive pattern forming substrate, wherein the fixing means fixes the protective layer to the transparent conductive layer in a state where gas exists in the gap in the insulating pattern. The conductive pattern forming substrate according to claim 1,
The conductive pattern forming substrate, wherein the fixing means connects the transparent conductive layer and the protective layer in a state where the transparent conductive layer and the protective layer are separated from each other in the thickness direction of the base material. The conductive pattern forming substrate according to claim 1,
The protective layer has a hard light transmissive panel,
The conductive pattern forming substrate, wherein the fixing means includes a soft transparent resin film in contact with both the transparent conductive layer and the protective layer. The conductive pattern forming substrate according to claim 1,
The fixing means is composed of a cured product of a fluid sandwiched between the transparent conductive layer and the protective layer,
The cured product of the fluid seals the gap in the insulating pattern in a state where air is sealed. The conductive pattern forming substrate. The conductive pattern forming substrate according to claim 1,
The transparent conductive layer is provided on both sides of the substrate,
The conductive pattern forming substrate, wherein the fixing means and the protective layer are provided on only one of the transparent conductive layers provided on both surfaces of the base material. The conductive pattern forming substrate according to claim 1,
The transparent conductive layer is provided only on one surface in the thickness direction of the base material with respect to the base material,
On the other surface in the thickness direction of the base material, a second base material different from the base material is provided,
The said 2nd base material is provided with the 2nd transparent conductive layer different from the said transparent conductive layer. The conductive pattern formation board | substrate characterized by the above-mentioned. The conductive pattern forming substrate according to claim 6,
The fixing means is in contact with the second transparent conductive layer and the first base material, and the first base material is fixed to the second transparent conductive layer,
Said 1st base material is said protective layer with respect to said 2nd transparent conductive layer. The conductive pattern formation board | substrate characterized by the above-mentioned. A conductive resin layer in which fine metal particles are dispersed in a light transmissive resin is formed on a light transmissive substrate,
Removing a part of the fine metal particles in the conductive resin layer to form an insulating pattern and a conductive pattern;
A light-transmitting protective layer is fixed to the conductive resin layer in a state where a gas exists in a gap when the fine metal particles are removed from the layer containing the fine metal particles and the light-transmitting resin. A method for producing a conductive pattern forming substrate.

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