JP2013098050A - Conductive pattern formation substrate and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive pattern formation substrate which reduces the visibility of a pattern, and to provide a manufacturing method of the conductive pattern formation substrate.SOLUTION: A conductive pattern formation substrate includes: a base material 2; a conductive pattern 5 including a metal nanowire and provided on the base material 2; an insulation pattern 6 contacting with the conductive pattern 5 and provided at a region different from a region where the conductive pattern 5 is formed; and a light diffusion layer 9 which at least partially covers at least one of the conductive pattern 5 and the insulation pattern 6.

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 base material, a conductive pattern including metal nanowires provided on the base material, and a region that is in contact with the conductive pattern and different from a region where the conductive pattern is formed. And a light diffusion layer that covers at least a part of at least one of the conductive pattern and the insulating pattern.

  Moreover, it is preferable that the said base material, the said conductive pattern and the said insulating pattern, and the said light-diffusion layer are laminated | stacked on the said conductive pattern formation board | substrate in this order.

  The light diffusing layer is preferably made of a resin containing a light diffusing agent and cured by a predetermined treatment.

  Further, at least a part of the insulating pattern is such that the conduction between the metal nanowires is released by removing at least a part of the metal nanowires from the cured binder containing the metal nanowires. A conductive pattern forming substrate.

  The conductive pattern forming substrate may further include an overcoat disposed between the conductive pattern and the insulating pattern and the light diffusion layer to cover both the conductive pattern and the insulating pattern.

  The light diffusion layer preferably has the same pattern shape as the insulating pattern.

  The method for producing a conductive pattern-formed substrate of the present invention is a method for producing the conductive pattern-formed substrate of the present invention, wherein a fluid-like or layer-like binder containing the metal nanowire is fixed on the base material. The insulating pattern is formed by irradiating the binder containing the metal nanowire with a laser beam to remove or disconnect a part of the metal nanowire, and a region different from the region where the insulating pattern is formed. Conductive pattern formation characterized in that at least a part is defined as the conductive pattern, and a light diffusion layer containing a light diffusing agent and cured by a predetermined treatment is laminated on at least one of the insulating pattern and the conductive pattern. A method for manufacturing a substrate.

  In the step of laminating the light diffusion layer, it is preferable that the light diffusion layer is laminated on the insulating pattern in accordance with the pattern shape of the insulating pattern.

  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 of the conductive pattern formation board of one embodiment of the present invention. It is sectional drawing in the AA of FIG. It is a flowchart which shows the manufacturing method of the conductive pattern formation board | substrate of the embodiment. It is process explanatory drawing which shows 1 process in the manufacturing method. It is process explanatory drawing which shows 1 process in the manufacturing method. It is process explanatory drawing which shows 1 process in the manufacturing method. It is sectional drawing which shows the modification of the conductive pattern formation board | substrate of the embodiment. It is a top view which shows the one part structure in the other structural example of the modification. It is a top view which shows a part of structure in the further another structural example of the modification. It is sectional drawing which shows the other modification of the conductive pattern formation board | substrate 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 of the present embodiment will be described. FIG. 1 is a schematic plan view of the conductive pattern forming substrate of the present embodiment. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIGS. 1 and 2, the conductive pattern forming substrate 1 includes a base material 2, a nanowire layer 4, an overcoat 8, and a light diffusion layer 9. In this embodiment, the base material 2, the nanowire layer 4, and the light diffusion layer 9 are laminated in this order.

The base material 2 is formed of a plate material, a film, a sheet, or a film and has an insulating property. In the present embodiment, the base material 2 is a polyethylene terephthalate sheet. In addition, as a material of the base material 2, polycarbonate, PEN, an acrylic resin, a cycloolefin polymer, etc. other than a polyethylene terephthalate can be employ | adopted.
On one surface of the base material 2 in the thickness direction, an undercoat 3 is provided for improving the adhesion between the base material 2 and another member. The undercoat 3 is made of an insulating material.

  The nanowire layer 4 has a conductive pattern 5 in which a plurality of metal nanowires are arranged in a circuit pattern, and an insulating pattern 6 that is insulative by removing the metal nanowires.

The conductive pattern 5 is a pattern provided on the substrate 2. In this embodiment, the metal nanowire provided in the conductive pattern 5 is bonded to the undercoat 3 by the adhesive force of a water-soluble polymer described later. The metal nanowire constituting the conductive pattern 5 is a fine metal wire having a length of about several tens of μm, for example. The material of the metal nanowire is preferably a highly conductive metal material such as silver, gold, copper, or aluminum. In the conductive pattern 5, the plurality of metal nanowires are distributed substantially uniformly. The plurality of metal nanowires are in contact with adjacent metal nanowires and are electrically connected to the adjacent metal nanowires. Note that the conductive pattern 5 may not be in direct contact with the base material 2 or the undercoat 3 as long as the positional relationship with the base material 2 is fixed.
In the present embodiment, the wiring 7 is connected to the conductive pattern 5. The wiring 7 is a wiring for electrically connecting the conductive pattern 5 to a wiring different from the conductive pattern forming substrate 1. As shown in FIG. 1, in the present embodiment, terminals 7 a in which the end portions of the wiring 7 are arranged and arranged are formed on the periphery of the conductive pattern forming substrate 1.

  The insulating pattern 6 is in contact with the conductive pattern 5 and is provided in a region different from the region where the conductive pattern 5 is formed. That is, the insulating pattern 6 is provided around the conductive pattern 5 and insulates between the lines constituting the conductive pattern 5. In the present embodiment, the insulating pattern 6 is formed with a plurality of fine cavities. This is a portion where the metal nanowires are arranged before the formation of the insulating pattern 6, and is caused by removing the metal nanowires from the nanowire layer 4 in the manufacturing method described later.

A difference in optical characteristics between the conductive pattern 5 and the insulating pattern 6 will be described.
Both the conductive pattern 5 and the insulating pattern 6 have light transmittance as a whole. In the conductive pattern 5, a part of the light is blocked by the metal nanowire, and a part of the light is reflected by the outer surface of the metal nanowire. As a result, light transmitted through the conductive pattern 5 and emitted to the upper surface of the conductive pattern forming substrate 1 is diffused. On the other hand, since the metal nanowire is removed from the insulating pattern 6, light is less likely to diffuse and reflect.
For this reason, the conductive pattern 5 and the insulating pattern 6 have a difference in light transmittance and haze value. Even when the metal nanowire remains in a part of the insulating pattern 6, the light transmittance and haze value of the conductive pattern 5 are unlikely to be completely the same as the insulating pattern 6.

  The overcoat 8 is a layer provided for the purpose of preventing the metal nanowires provided on the nanowire layer 4 from falling off the base material 2. The overcoat 8 is formed of a resin material that is cured by a predetermined treatment, and has an insulating property. As a material for the overcoat 8, an ultraviolet curable resin, an adhesive, or the like can be used. In this embodiment, the material of the overcoat 8 is an ultraviolet curable acrylic resin. The overcoat 8 is in contact with the nanowire layer 4 and covers the nanowire layer 4. Further, a part of the metal nanowire forming the conductive pattern 5 is embedded in the overcoat 8.

The light diffusion layer 9 is a layer laminated on the overcoat 8 and covers all of the conductive pattern 5 and the insulating pattern 6. As a material of the light diffusion layer 9, a resin that contains a light diffusion agent and is cured by a predetermined treatment can be employed. As the light diffusing agent, for example, beads or particles made of a light-transmitting material can be employed. Examples of the resin that is cured by the predetermined treatment include an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin.
Specific examples of the light diffusion layer 9 include acrylic, urethane, polycarbonate, and polyester. The type of resin is not limited as long as it is in close contact with the overcoat 8 and transparency can be secured. As the predetermined treatment for curing the resin, in addition to ultraviolet curing and thermal curing, a treatment in which the resin is dissolved in a solvent and then evaporated can be used. Further, the above-described processes may be combined.

  Moreover, as an example of the light diffusing agent applicable to the light diffusing layer 9, a light diffusing agent having a particle size of 0.1 μm or more and 10 μm or less is preferable. When the particle size is 0.1 μm or more and 10 μm or less, the particle size is sufficiently larger than the wavelength of light and the specific surface area of the light diffusing agent is large, so that the efficiency of diffusing light is good. When the particle size is 0.1 μm or less, the particle size with respect to the wavelength of light may be insufficient. Moreover, the specific surface area of a light-diffusion agent may become inadequate that a particle size is 10 micrometers or more. In the case where aggregation occurs in the light diffusing agent due to the formation of the light diffusion layer 9, the secondary particle diameter after aggregation is preferably 0.1 μm or more and 10 μm or less. In this case, the particle size of the primary particles before aggregation may be less than 0.1 μm.

  The refractive index of the light diffusing agent is preferably smaller than the refractive index of the resin contained in the light diffusing layer 9. Furthermore, the greater the difference in refractive index between the light diffusing agent and the resin, the higher the effect of diffusing light. When the refractive index between the light diffusing agent and the resin is large, the amount of light reflected at the interface between the light diffusing agent and the resin increases, so that the effect of diffusing light is high. In addition, when the refractive index of a light-diffusion agent is larger than the refractive index of resin, the total light transmittance of the light-diffusion layer 9 falls, and the quantity which can contain a light-diffusion agent decreases.

  Examples of the material for the light diffusing agent include silicon dioxide, glass mainly containing silicon dioxide, and silicone. For the purpose of lowering the refractive index, a porous material or a hollow material can be used as the material for the light diffusing agent. The light diffusing agent may have a spherical shape, a scaly shape, or an indefinite shape.

  In this embodiment, the light diffusion layer 9 also functions as a protective layer for protecting the conductive pattern 5 formed on the conductive pattern forming substrate 1 from external force and preventing disconnection.

  Next, the manufacturing method of the conductive pattern forming substrate 1 of the present embodiment will be described by taking the case of manufacturing the above-described conductive pattern forming substrate 1 as an example. FIG. 3 is a flowchart showing the method for manufacturing the conductive pattern forming substrate of the present embodiment. 4 to 6 are process explanatory views showing one process in the manufacturing method of the conductive pattern forming substrate of the present embodiment.

First, as shown in FIG. 4, a solution in which metal nanowires and a binder are mixed is applied to the surface of the undercoat 3 on one surface in the thickness direction among the outer surfaces of the substrate 2 (steps shown in FIG. 3). S1). In the present embodiment, the solution in which metal nanowires are dispersed includes metal nanowires, a water-soluble polymer, and an aqueous solvent.
In step S <b> 1, as shown in FIG. 4, the solution in which the metal nanowires are dispersed is solidly applied to the outer surface of the substrate 2. The solution in which the metal nanowires are dispersed is in a state where it is uniformly applied to the entire one surface in the thickness direction of the outer surface of the substrate 2. The nanowire layer 4 is formed on the base material 2 by applying the solution in which the metal nanowires are dispersed to the outer surface of the base material 2.
Step S1 is complete | finished now and it progresses to step S2.

Step S2 is a step of removing at least a part of the solvent from the solution applied on the substrate 2.
In step S2, the base material 2 coated with the solution in which the metal nanowires are dispersed is dried, and the aqueous solvent contained in the solution is evaporated. Thereby, metal nanowire and a water-soluble polymer remain on the base material 2, and metal nanowire adheres to the base material 2 with a water-soluble polymer.
Step S2 is complete | finished now and it progresses to step S3.

Step S3 is a step of forming the overcoat 8.
In step S3, an ultraviolet curable acrylic resin is applied on the nanowire layer 4 as shown in FIG. Further, the applied ultraviolet curable acrylic resin is irradiated with ultraviolet rays to cure the ultraviolet curable acrylic resin. As a result, a layer made of an insulating material covering the nanowire layer 4 is formed, and the overcoat 8 is formed.
Step S3 is complete | finished now and it progresses to step S4.
Although not shown, the wiring 7 can be formed in either step S2 or step S3. As a method for forming the wiring 7, for example, a method of forming a metal paste pattern by screen printing can be employed.

Step S <b> 4 is a step of forming the conductive pattern 5 and the insulating pattern 6.
In step S4, the nanowire layer 4 is irradiated with the laser light L through the overcoat 8, as shown in FIG. Thereby, in the nanowire layer 4, the metal nanowire located in the part irradiated with the laser beam L is collapsed, and the metal nanowire that is in a wire shape is removed from the nanowire layer 4. Thereby, in the part irradiated with the laser beam L, the contact between the metal nanowires is lost, and thus the conductivity is lost. That is, the portion irradiated with the laser light L becomes the insulating pattern 6, and the rest becomes the conductive pattern 5. In addition, it is not necessary to use all the portions that have not been irradiated with the laser light L as wirings. For example, an electrically floating pattern serving as a shield against noise may be provided in the nanowire layer 4. Further, even if the metal nanowires are not completely removed in the insulating pattern 6, if the laser light L is irradiated so that the metal nanowires are disconnected, the insulating property with respect to the conductive pattern 5 can be made comparable. .
The nanowire layer 4 can also be irradiated with the laser light L through the base material 2 by appropriately selecting the material of the base material 2.
Step S4 is complete | finished now and it progresses to step S5.

Step S <b> 5 is a step of forming the light diffusion layer 9.
In step S <b> 5, as shown in FIG. 2, the light diffusing agent is dispersed in the fluid resin, and a mixture of the fluid resin and the light diffusing agent is applied on the overcoat 8. In the present embodiment, the mixture is uniformly solid-coated on the overcoat 8, and then the mixture is subjected to a predetermined treatment and cured. The predetermined treatment is selected according to the material constituting the light diffusion layer 9. For example, when an ultraviolet curable resin is employed as the fluid resin in the light diffusion layer 9, the mixture of the ultraviolet curable resin and the light diffusing agent is irradiated with ultraviolet rays. In the case of a mixture of a thermosetting resin and a light diffusing agent, the mixture is heated.
This ends step S5.

Next, the operation of the conductive pattern forming substrate 1 of the present embodiment will be described.
The conductive pattern 5 and the insulating pattern 6 provided on the nanowire layer 4 have different optical characteristics depending on the presence or absence of metal nanowires. For example, in the present embodiment, the haze value of the insulating pattern 6 is lower than the haze value of the conductive pattern 5.
However, in the present embodiment, since the light diffusion layer 9 is provided, the light emitted from the substrate 2 side toward the light diffusion layer 9 side diffuses in the light diffusion layer 9. As a result, the boundary between the conductive pattern 5 and the insulating pattern 6 becomes unclear, and the shape of the conductive pattern 5 is inconspicuous for those who see the nanowire layer 4 through the light diffusion layer 9.

  Thus, according to the conductive pattern forming substrate 1 of the present embodiment, the pattern appearance can be reduced by providing the light diffusion layer 9.

  Moreover, in this embodiment, since the overcoat 8 is provided between the conductive pattern 5 and the insulating pattern 6 and the light diffusion layer 9, it is possible to prevent the metal nanowires from falling off the base material 2. .

(Modification 1)
Next, a modification of the above embodiment will be described. FIG. 7 is a cross-sectional view showing a conductive pattern forming substrate of this modification, and is a cross-sectional view taken along the line AA of FIG. FIG. 8 is a plan view showing another configuration example of the present modification, and is an enlarged view of a region similar to the region indicated by the symbol X in FIG. FIG. 9 is a plan view showing another configuration example of the present modification, and is an enlarged view of a region similar to the region indicated by the symbol X in FIG.

As shown in FIG. 7, the conductive pattern forming substrate 1 </ b> A of this modification is different in the shape of the light diffusion layer 9 formed on the overcoat 8.
The light diffusing layer 9 </ b> A of this modification has the same shape as the pattern shape of the insulating pattern 6 when viewed from the thickness direction of the conductive pattern forming substrate 1.
In the present modification, the insulating pattern 6 is transmitted through the insulating pattern 6 in consideration of the fact that light reflected from the outer surface of the metal nanowire and emitted toward the substrate 2 side is less than that of the conductive pattern 5. The diffused light is diffused in the light diffusion layer 9A.

Even with such a configuration, pattern appearance can be reduced. Moreover, since light is emitted without passing through the light diffusion layer 9A in the conductive pattern 5 portion, the amount of emitted light is larger than that of the conductive pattern forming substrate 1 of the above-described embodiment.
In addition, when there is no large deviation in the area ratio and distribution between the conductive pattern 5 and the insulating pattern 6 on the substrate 2, the amount of the fluid resin and the light diffusing agent used is reduced while suppressing unevenness in optical characteristics. Can be reduced.
In addition, the light diffusion layer 9B having the same shape as the pattern shape of the conductive pattern 5 when viewed from the thickness direction of the conductive pattern forming substrate 1 may be laminated instead of the light diffusion layer 9A.

  Further, instead of the light diffusion layer 9A having the same shape as the pattern shape of the insulating pattern 6, a part of the insulating pattern 6 protrudes from the outline of the insulating pattern 6 when viewed from the thickness direction of the conductive pattern forming substrate 1. A light diffusion layer 9 </ b> C covering the conductive pattern 5 may be provided (see FIG. 8). For example, in the example shown in FIG. 8, the width dimension W2 of the light diffusion layer 9C is wider than the width dimension W1 of the insulating pattern 6. As described above, the position of the contour line when the light diffusion layer and the insulating pattern are viewed from the thickness direction of the conductive pattern forming substrate 1 may not exactly match. In this specification, “the light diffusion layer has the same pattern shape as the insulating pattern” includes the case where the light diffusion layer has substantially the same pattern shape as the insulating pattern.

  Furthermore, the insulating pattern 6 may be provided with an island pattern 5A in which metal nanowires remain without being irradiated with the laser light L (see FIG. 9). The island pattern 5 </ b> A is insulated from the conductive pattern 5. Further, the island pattern 5 </ b> A has the same optical characteristics as the conductive pattern 5. For this reason, since the island-shaped pattern 5A is formed in the insulating pattern 6, the difference in optical characteristics with the conductive pattern 5 is reduced.

(Modification 2)
Next, another modification of the above-described embodiment will be described. FIG. 10 is a cross-sectional view showing the conductive pattern forming substrate of this modification, and is a cross-sectional view taken along the line AA of FIG.
As shown in FIG. 10, in the conductive pattern forming substrate 1 </ b> B of this modification, the light diffusion layer 9 is directly laminated on the nanowire layer 4 without the overcoat 8.
In this modification, after the nanowire layer 4 is formed on the substrate 2, the conductive pattern 5 and the insulating pattern 6 are formed before the light diffusion layer 9 is laminated. After the conductive pattern 5 and the insulating pattern 6 are formed, the light diffusion layer 9 is formed by the same process as step S5 of the first embodiment described above.
In this modification, the light diffusion layer 9 also has the same function as the overcoat 8. Thereby, the manufacturing process of the conductive pattern formation board | substrate 1B can be simplified. Moreover, since the overcoat 8 is unnecessary, it can be set as a thin conductive pattern forming substrate with high light transmittance.

  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.

1, 1A, 1B Conductive pattern forming substrate 2 Substrate 3 Undercoat 4 Nanowire layer 5 Conductive pattern 6 Insulating pattern 7 Wiring 8 Overcoat 9 Light diffusion layer NW Metal nanowire

Claims (8)

A substrate;
Conductive pattern provided in a state in which the positional relationship is fixed with respect to the substrate including metal nanowires,
An insulating pattern in contact with the conductive pattern and provided in a region different from the region where the conductive pattern is formed;
A light diffusion layer covering at least a part of at least one of the conductive pattern and the insulating pattern;
A conductive pattern forming substrate comprising: The conductive pattern forming substrate according to claim 1,
The conductive pattern forming substrate, wherein the base material, the conductive pattern and the insulating pattern, and the light diffusion layer are laminated in this order. The conductive pattern forming substrate according to claim 1 or 2,
The conductive pattern forming substrate, wherein the light diffusing layer is made of a resin containing a light diffusing agent and cured by a predetermined treatment. The conductive pattern forming substrate according to any one of claims 1 to 3,
At least a part of the insulating pattern is characterized in that the conduction between the metal nanowires is released by removing at least a part of the metal nanowires from a cured product of the binder containing the metal nanowires. Conductive pattern forming substrate. The conductive pattern forming substrate according to any one of claims 1 to 4,
A conductive pattern forming substrate, further comprising an overcoat disposed between the conductive pattern and the insulating pattern and the light diffusion layer and covering both the conductive pattern and the insulating pattern. A conductive pattern forming substrate according to any one of claims 1 to 5,
The conductive pattern forming substrate, wherein the light diffusion layer has the same pattern shape as the insulating pattern. A method for producing a conductive pattern forming substrate according to any one of claims 1 to 6,
On the base material, a fluid-like or layer-like binder containing the metal nanowire is fixed,
The insulating pattern is formed by irradiating the binder containing the metal nanowire with laser light to remove or disconnect a part of the metal nanowire,
Defining at least a part of a region different from the region where the insulating pattern is formed as the conductive pattern;
A light diffusing layer containing a light diffusing agent and cured by a predetermined treatment is laminated on at least one of the insulating pattern and the conductive pattern;
The manufacturing method of the conductive pattern formation board | substrate characterized by the above-mentioned.   8. The method of manufacturing a conductive pattern forming substrate according to claim 7, wherein in the step of laminating the light diffusion layer, the light diffusion layer is laminated on the insulating pattern according to a pattern shape of the insulating pattern. A method for producing a conductive pattern forming substrate.

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