JPWO2019234841A1 - Flexible circuit with cable and its manufacturing method, and flexible circuit intermediate with cable - Google Patents

Abstract

An object of the present invention is to provide a flexible circuit with a cable, a method for manufacturing the same, and an intermediate thereof, which are excellent in productivity and reliability of electrical connection, and a conductor is formed on at least one surface of the flexible base material 1. A circuit unit 2 provided with a circuit 21 composed of the above, and a cable unit 3 composed of a conductor and provided with a wiring 31 having one end connected to the circuit 21 and the other end for connecting to an external circuit. The conductors that are printed and the conductors that make up the wiring 31 commonly contain at least one kind of metal, and the thickness of the conductors that make up the wiring 31 is the thickness of the conductors that make up the circuit 21. It is solved by being larger.

Description

The present invention relates to a flexible circuit with a cable and a method for manufacturing the same, and more specifically, a flexible circuit with a cable and a method for manufacturing the same, which are excellent in productivity and reliability of electrical connection. Also related to flexible circuit intermediates with cables.

A technique for providing a touch sensor circuit on a base material is known (Patent Documents 1 and 2).

When connecting a circuit provided on a substrate to an external circuit provided on an external component, an FFC (flat flexible cable) or an FPC (flexible printed circuit) is used (Patent Documents 3 to 6).

Japanese Unexamined Patent Publication No. 2015-18494 Japanese Unexamined Patent Publication No. 2017-20387 Japanese Unexamined Patent Publication No. 2010-278067 Japanese Unexamined Patent Publication No. 2016-189240 Japanese Unexamined Patent Publication No. 2012-38710 Japanese Unexamined Patent Publication No. 2006-156079 Japanese Unexamined Patent Publication No. 2004-31858

The present inventor has provided a circuit unit and a cable unit that can substitute for an FFC or FPC on a flexible base material, and attempted to connect to an external circuit using the cable unit. In order to put such a technology into practical use, it is required to have excellent productivity and reliability of electrical connection.

Patent Documents 1 to 7 do not solve such a problem.

Therefore, an object of the present invention is to provide a flexible circuit with a cable, a method for manufacturing the same, and a flexible circuit intermediate with a cable, which are excellent in productivity and excellent in reliability of electrical connection.

Further, other problems of the present invention will be clarified by the following description.

The above problems are solved by the following inventions.

1. 1.
On at least one surface of the flexible base material, there is a circuit portion provided with a circuit composed of conductors, and a wiring composed of conductors and having one end connected to the circuit and the other end for connecting to an external circuit. The provided cable part is printed,
The conductor constituting the circuit and the conductor constituting the wiring commonly contain at least one kind of metal.
The thickness of the conductor constituting the wiring is larger than the thickness of the conductor constituting the circuit.
The flexible base material includes a base material main body and a band-shaped portion extending in a band shape from the base material main body.
The circuit portion is provided on the base material main body, and the cable portion is provided on the strip-shaped portion.
A flexible circuit with a cable in which the other end of the wiring constituting the cable portion is provided at the tip of the strip-shaped portion.
2.
The flexible circuit with a cable according to 1 above, wherein the conductor constituting the circuit and the conductor constituting the wiring are alloys, respectively.
3. 3.
The flexible circuit with a cable according to the above 2, wherein the alloy constituting the circuit and the alloy constituting the wiring commonly contain one or more selected from nickel, chromium, molybdenum, manganese and cobalt.
4.
The thickness of the conductor constituting the circuit is 0.05 μm to 10 μm.
The flexible circuit with a cable according to any one of 1 to 3 above, wherein the thickness of the conductor constituting the wiring is 1.5 to 10 times the thickness of the conductor constituting the circuit.
5.
The flexible circuit with a cable according to any one of 1 to 4, wherein a protective material is laminated on the circuit and the wiring so as to expose the other end of the wiring.
6.
The flexible circuit with a cable according to any one of 1 to 5, wherein the circuit is a touch sensor circuit composed of a plurality of sensor channels.
7.
The flexible circuit with a cable according to any one of 1 to 5, wherein the circuit is a heating element circuit that generates heat when energized.
8.
A manufacturing method for manufacturing a flexible circuit with a cable according to any one of 1 to 7 above.
When the circuit and the wiring are formed by combining the printing method and the plating process, the circuit and the wiring are formed so that the thickness of the conductor constituting the wiring is larger than the thickness of the conductor constituting the circuit. A method for manufacturing a flexible circuit with a cable, which makes at least one of printing conditions and plating conditions different.
9.
In the printing method for forming the circuit and the wiring, the amount of ink applied per unit area to the wiring is made larger than the amount of ink applied per unit area to the circuit. How to make a circuit.
10.
8. The method for manufacturing a flexible circuit with a cable according to 8 or 9, wherein in the plating process for forming the circuit and the wiring, the plating time for the wiring is longer than the plating time for the circuit.
11.
In the plating process for forming the circuit and the wiring, electrolytic plating is used, and the amount of plating current per unit area of the wiring is made larger than the amount of plating current per unit area of the circuit. The method for manufacturing a flexible circuit with a cable according to any one of 8 to 10.
12.
A circuit portion provided with a circuit composed of conductors on at least one surface of a long flexible base material, one end formed of a conductor and connected to the circuit, and the other end for connecting to an external circuit. A plurality of units composed of a cable portion provided with wiring having a wire are printed along the longitudinal direction of the flexible base material.
The conductor constituting the circuit and the conductor constituting the wiring commonly contain at least one kind of metal.
A flexible circuit intermediate with a cable in which the thickness of the conductors constituting the wiring is larger than the thickness of the conductors constituting the circuit.
13.
The flexible circuit intermediate with a cable according to the above 12, wherein at least one wiring constituting the unit extends from the circuit toward a long side of the flexible base material.

According to the present invention, it is possible to provide a flexible circuit with a cable having excellent productivity and excellent reliability of electrical connection, a method for manufacturing the same, and a flexible circuit intermediate with a cable.

The figure explaining an example of the flexible circuit with a cable The figure explaining an example of the protective material Diagram illustrating another example of a flexible circuit with cable The figure explaining an example of the method of forming a conductive thin wire The figure explaining the first aspect of mesh pattern formation The figure explaining the second aspect of mesh pattern formation The figure explaining an example of the flexible circuit intermediate with a cable

Hereinafter, embodiments for carrying out the present invention will be described in detail.

1. 1. Flexible Circuit with Cable FIG. 1 is a diagram illustrating an example of a flexible circuit with a cable according to the present invention.

In the flexible circuit with a cable shown in FIG. 1, a circuit portion 2 and a cable portion 3 are printed on one surface of the flexible base material 1.

[Flexible base material]
The material of the flexible base material (hereinafter, also simply referred to as a base material) 1 is not particularly limited, and examples thereof include resins. Examples of the resin include polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, polybutylene terephthalate resin, cellulose-based resin (polyacetyl cellulose, cellulose diacetate, cellulose triacetate, etc.), polyethylene resin, polypropylene-based resin, and the like. Methacrylic resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile- (poly) styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, poly (meth) Examples thereof include acrylic resins, polycarbonate resins, polyester resins, polyimide resins, polyamide resins, polyamideimide resins, cycloolefin polymer (COP) resins and the like. By using these resins, good flexibility can be imparted to the base material 1. Further, by using these resins, good insulation and transparency can be imparted to the base material 1. The base material 1 made of resin can be, for example, a film. The base material 1 made of resin may be stretched or unstretched.

The thickness of the base material 1 is not particularly limited, and can be, for example, about 1 μm to 10 cm, and further about 20 μm to 300 μm.

The base material 1 may be subjected to surface treatment for changing the surface energy. Further, the base material 1 may be a laminated body, or may have a hard coat layer, an antireflection layer, or the like.

The base material 1 includes a rectangular base material main body 11 and a strip-shaped portion 12 extending in a strip shape from the base material main body 11. The strip-shaped portion 12 is provided in a convex shape from the side surface of the base material main body 11 in the surface direction (direction orthogonal to the thickness direction) of the base material 1. The base material main body 11 and the strip-shaped portion 12 are integral with each other, and are formed by cutting the outer shape of one base material. In the base material 1, the base material main body 11 is provided with a circuit portion 2, and the strip-shaped portion 12 is provided with a cable portion 3.

[Circuit part]
As shown in FIG. 1, a circuit 21 composed of conductors is printed on a base material 1 constituting the circuit unit 2. Here, a touch sensor circuit is shown as an example of the circuit 21. The touch sensor circuit is composed of a plurality of sensor channels 22 printed on the base material 1. The plurality of sensor channels 22 constituting the touch sensor circuit can be used for detecting the touch position.

Each sensor channel 22 is formed in a band shape. A plurality of band-shaped sensor channels 22 are arranged side by side at predetermined intervals in the width direction of the band.

The circuit 21 constituting the circuit unit 2 further includes a plurality of drawer wirings 23 printed on the base material 1. One end of the lead wire 23 is connected to the sensor channel 22. As a result, the lead wiring 23 and the sensor channel 22 are electrically connected. The electrical connection here means that it is conductive. Further, the other ends of the plurality of lead-out wirings 23 are concentrated in the central end 24 of the base end of the cable portion 3 (the base end of the strip-shaped portion of the base material 1). Here, the fact that the line spacing (also referred to as Line &Space; L / S) of the plurality of lead wiring 23 is concentrated in the aggregation unit 24 means that the line spacing (also referred to as Line &Space; L / S) is more concentrated than one end side connected to the plurality of sensor channels 22. It can be narrower on the other end side located at 24.

[Cable part]
A plurality of wirings 31 composed of conductors are printed on the base material 1 constituting the cable portion 3.

In the cable portion 3, the plurality of wirings 31 extend from the base end to the tip end of the cable portion 3. The plurality of wirings 31 extend parallel to each other along the longitudinal direction of the cable portion.

One end of the wiring 31 is electrically connected to the circuit 21 of the circuit unit 2. That is, one end of the wiring 31 is arranged in the aggregation portion 24 at the base end of the cable portion 3, and is electrically connected to the other end of the drawer wiring 23 aggregated in the aggregation portion 24.

The other end of the wiring 31 is arranged at the tip of the cable portion 3 (the tip of the strip-shaped portion of the base material 1), and forms a connecting portion for electrically connecting the wiring 31 to an external circuit (not shown). The tip edge of the cable portion 3 is formed linearly, and the other ends of the plurality of wirings 31 are arranged side by side on the tip edge to form a connecting portion.

The external circuit may be, for example, a circuit mounted on an external component (external board) (not shown). More specifically, for example, when the circuit unit 2 is composed of a touch sensor circuit, the external circuit may be composed of an integrated circuit (IC) or the like that performs an operation for position detection.

By connecting the other end of the wiring 31 arranged at the tip of the cable unit 3 to a connector (for example, an FFC connector or an FPC connector) mounted on an external component having the above-mentioned external circuit, the circuit 21 of the circuit unit 2 can be connected. Can be electrically connected to an external circuit. Alternatively, even if the connector is not mounted on the external component, the other end of the wiring 31 arranged at the tip of the cable portion 3 is externally attached by using, for example, a conductive adhesive or an ACF (anisometric conductive film). Can be electrically connected to the circuit.

Therefore, according to the flexible circuit with a cable according to the present embodiment, the tip of the cable portion 3 can be directly joined to an external component, and it is not necessary to separately interpose an external connecting component such as an FFC or an FPC. ..

Further, according to the flexible circuit with a cable according to the present embodiment, since the cable portion 3 is integrally formed with the circuit portion 2, a step of connecting an external connection component such as an FFC or an FPC to the circuit portion 2. Can be omitted.

The base material constituting the FFC or FPC is generally made of a highly heat-resistant resin such as polyimide so as to withstand the high temperature when the FFC or FPC is soldered to the substrate or the like. Therefore, FFC and FPC have a low degree of freedom in selecting the base material and are expensive.

On the other hand, in the present embodiment, the circuit unit 2 and the cable unit 3 are integrated in the base material 1, and the conductor is continuously printed from the circuit 21 of the circuit unit 2 to the wiring 31 of the cable unit 3. Therefore, soldering is not required between the circuit unit 2 and the cable unit 3. Therefore, the degree of freedom in selecting the base material is high, and the cost can be reduced.

For example, the base material 1 can be made of a material having a lower heat resistance than polyimide (for example, a material having a melting point lower than that of polyimide), and for example, PET or the like can be used to impart good flexibility to the base material 1. At the same time, cost reduction can be realized.

〔conductor〕
The conductor constituting the circuit 21 of the circuit unit 2 and the conductor constituting the wiring 31 of the cable unit 3 are each composed of at least metal. The metals constituting these conductors are not particularly limited, but for example, Au, Pt, Ag, Cu, Ni, Cr, Rh, Pd, Zn, Co, Mo, Ru, W, Os, Ir, Fe, Mn, Ge. , Sn, Ga, In and the like.

Further, one or both of the conductors constituting the circuit 21 and the conductors constituting the wiring 31 may be made of an alloy. In particular, it is preferable that both the conductor constituting the circuit 21 and the conductor constituting the wiring 31 are alloys. The alloy may be composed of a plurality of metals selected from the metals described above.

The alloy referred to here may be, for example, a conductor composed of a plurality of types of metals (metal elements) as a whole. The alloy may be, for example, a solid solution in which a plurality of metals are completely dissolved at the atomic level, a eutectic in which a plurality of metals are independent at the crystal level, or a kind of metal. Other types of metals may be laminated on top of each other in layers. A preferable example of a conductor made of an alloy is one in which one or more plating layers made of another kind of metal are provided on one kind of metal.

The conductor constituting the circuit 21 and the conductor constituting the wiring 31 commonly contain at least one kind, preferably two or more kinds, and more preferably three or more kinds of metals. By including the common metal in the conductor constituting the circuit 21 and the conductor constituting the wiring 31, for example, it becomes possible to use a common ink when printing these. Further, when the circuit 21 and the wiring 31 are formed by plating in addition to the printing method, it is possible to use a common plating bath for the plating. As a result, the number of steps (number of printings, number of platings, etc.) for manufacturing a flexible circuit with a cable can be reduced, and productivity can be improved.

Most preferably, the conductor constituting the circuit 21 is made of n (n is an integer of 1 or more) metal, and the conductor constituting the wiring 31 also constitutes the circuit 21. It is composed of n kinds of metals of the same kind as the conductor. Here, the mass ratio of each of the n types of metals may be the same or different between the conductors constituting the circuit 21 and the conductors constituting the wiring 31.

The metal type commonly contained in the conductor constituting the circuit 21 and the conductor constituting the wiring 31 is not particularly limited and may be selected from, for example, those exemplified as the metal constituting the conductor. In particular, Ni, Cr, It is preferably a metal selected from Mo, Mn and Co.

In particular, when the conductor constituting the circuit 21 and the conductor constituting the wiring 31 are alloys, these alloys share one or more metals selected from Ni, Cr, Mo, Mn and Co. It is preferable to include in. Since these metals are excellent in durability, excellent durability can be imparted to the circuit 2 and the wiring 3. As a result, when the cable portion 3 is bent for connection with an external circuit or the other end of the wiring 31 is physically connected to the external circuit, the wiring 31 is prevented from being disconnected and is electrically connected. The reliability of the connection can be improved. Further, when the circuit unit 2 is bent and used, the circuit 21 is prevented from being disconnected, and the function of the circuit 21 (the function of detecting the touch position in the present embodiment) is satisfactorily exhibited.

The upper limit of the number of metal types commonly contained in the conductor constituting the circuit 21 and the conductor constituting the wiring 31 is not particularly limited, but may be, for example, 5 or less.

It is preferable that the conductor constituting the circuit 21 and the conductor constituting the wiring 31 share a common metal contained as a main component. When the conductor is composed of a kind of metal, the main component referred to here is the kind of metal, and when the conductor is an alloy, it is a metal that occupies the largest mass ratio in the alloy.

The thickness of the conductor constituting the wiring 31 is larger than the thickness of the conductor constituting the circuit 21. In particular, the thickness of the conductor constituting the circuit 21 is preferably 0.05 μm to 10 μm, and the thickness of the conductor constituting the wiring 31 is 1.5 to 10 times the thickness of the conductor constituting the circuit 21. Is preferable. As a result, it is possible to impart particularly excellent durability to the wiring 3. Therefore, when the cable portion 3 is bent for connection with an external circuit or the other end of the wiring 31 is physically connected to the external circuit, the wiring 31 is prevented from being broken and the wiring is electrically connected. The reliability of the can be improved. Further, even if the other end of the wiring 31 is worn by repeatedly physically joining and detaching the other end of the wiring 31 and the external circuit, the effect of stably maintaining the electrical connection can be obtained.

[Protective material]
It is preferable to protect the circuit 21 and the wiring 31 described above with a protective material.

For example, as shown in FIG. 2, it is preferable that the protective material 4 is laminated on the circuit 21 and the wiring 31 so as to expose the other end of the wiring 31. As a result, the exposed other end 32 of the wiring 31 can be suitably used for joining with an external component (not shown), and the circuit 21 and the wiring 31 excluding the other end 32 are suitably protected by the protective material 4. it can.

In the example of FIG. 2, the protective material 4 is provided as a protective layer laminated on the base material 1. In this case, the circuit 21 of the circuit unit 2 and the wiring 31 of the cable unit 3 are arranged between the base material 1 and the protective layer. The protective layer can form the surface of a flexible circuit with a cable.

As the protective material 4, for example, a resin or the like can be used. The resin is not particularly limited, and examples thereof include an active energy ray-curable resin obtained by irradiating and curing an active energy ray such as an ultraviolet ray or an electron beam. Examples of the active energy ray-curable resin include a cationic curable active energy ray-curable resin.

The cation-curable active energy ray-curable resin is formed by irradiating a cation-curable compound (also referred to as a cation-curable monomer) with active energy rays and curing the resin. As the cation-curable monomer, a cation-curable monomer known per se can be used, and examples thereof include an epoxy compound, a compound having an oxetane ring, and a compound having a vinyl ether structure.

The protective layer made of the protective material 4 may be formed directly on the circuit 21 and the wiring 31, but may be formed on the circuit 21 and the wiring 31 via an intermediate layer (not shown). By providing the intermediate layer, corrosion of the circuit 21 and the wiring 31 due to the components from the protective layer can be reliably prevented. Acids are examples of components from the protective layer that can cause corrosion.

As an intermediate layer, it is preferable to provide a layer for preventing the acid from the protective layer from moving to the circuit 21 and the wiring 31. From this point of view, the intermediate layer is preferably, for example, a layer that neutralizes or traps the acid, or a layer that barriers the acid.

Neutralizing an acid means, for example, that the acid reacts with a base to form a salt such as a metal salt. Capturing an acid means, for example, electrically adsorbing an acid with a substance having an opposite charge, or physically adsorbing an acid compound with a compound having a structure that incorporates the acid compound. The intermediate layer that neutralizes or traps the acid can contain a basic compound or an acid scavenger.

Intermediate layer barrier acid is preferably permeation of acid is very small layer within a practical range, for example, the oxygen permeability coefficient is 1 [cc / (m 2 · day · atm)] or less, or a water vapor transmission It is a layer having a coefficient of 1 [g / (m ² · day)] or less. These coefficients are values measured at 25 ° C.

The acid barrier layer can be formed by, for example, a film such as an inorganic or metal oxide, and specifically, for example, a layer obtained by subjecting a polysilazane layer to silica conversion is preferably used.

[Other aspects]
In the above description, the case where the circuit portion and the cable portion are provided on one surface of the base material has been shown, but the present invention is not limited to this. For example, circuit sections may be provided on both sides of the base material. When the circuit portion is provided on both sides of the base material, the cable portion can be provided on one side or both sides of the base material. This will be described with reference to FIG.

In the example of FIG. 3, the flexible circuit with a cable includes circuit portions 2 on both sides of the base material 1.

The circuit unit 2 on one surface (also referred to as the front surface) and the circuit unit 2 on the other surface (also referred to as the back surface) are arranged so as to overlap with each other via the base material 1.

The plurality of sensor channels 22 constituting the circuit 21 of the circuit unit 2 on the surface extend in the vertical direction in FIG. On the other hand, the plurality of sensor channels 22 constituting the circuit 21 of the circuit unit 2 on the back surface extend in the left-right direction in FIG. By crossing the sensor channels 22 between the front and back surfaces of the base material 1 in this way, it is possible to detect the touch position in the XY coordinate system.

In the example of FIG. 3, the cable portion 3 corresponding to the circuit portion 2 on the front surface is provided on the front surface, and the cable portion 3 corresponding to the circuit portion 2 on the back surface is provided on the back surface. As a result, the cable portions 3 are provided on both sides of the base material 1.

The example is not limited to the example of FIG. 3, and for example, the cable portion 3 corresponding to the circuit portion 2 on the front surface may be provided on the front surface, and the cable portion 3 corresponding to the circuit portion 2 on the back surface may also be provided on the front surface. In this case, for example, a through hole (not shown) is provided on the base material 1, and the lead wiring 23 corresponding to the circuit portion 2 on the back surface is drawn out to the front surface through the through hole and connected to the wiring 31 of the cable portion provided on the front surface. can do.

In the example of FIG. 3, two cable portions 3 are provided on different sides (upper side and right side in FIG. 3) of the rectangular base material main body 11, but a plurality of cable portions 3 are provided on the same side. It may be provided together with the band-shaped portion 12 of the above.

Further, one cable portion 3 may be provided corresponding to both the circuit portion 2 on the front surface and the circuit portion 2 on the back surface.

Depending on the arrangement of the lead-out wiring 23, the cable portion 3 can be provided at an arbitrary position desired. The cable portion 3 is not limited to the case where it extends from the side of the rectangular base material main body 11, and may be extended from the corner of the base material main body 11, for example.

In the above description, the case where a plurality of wirings 31 are provided in the cable portion 3 has been mainly described, but the present invention is not limited to this. The number of wirings 31 provided in the cable portion 3 may be one. When there is only one wiring 31, the above-mentioned aggregation unit 24 can be omitted.

Further, in the above description, the case where the circuit 21 provided in the circuit unit 2 is a touch sensor circuit is mainly shown, but the present invention is not limited to this. It is preferable that the circuit exerts any function by being electrically connected to an external circuit. Examples of the function exhibited by the circuit include a function of inputting and / or outputting a signal, a function of inputting or outputting energy, and the like. Specific examples of such a circuit include a heating element circuit that generates heat when energized, an antenna circuit that receives a signal such as an electromagnetic wave, and the like.

2. Method for Manufacturing Flexible Circuit with Cable The method for manufacturing a flexible circuit with cable according to the present invention can be used for manufacturing a flexible circuit with cable as described above. As for this manufacturing method, the description of the flexible circuit with a cable is appropriately incorporated.

In this manufacturing method, when the circuit 21 of the circuit unit 2 and the wiring 31 of the cable unit 3 are formed by combining the printing method and the plating process, the thickness of the conductor constituting the wiring 31 constitutes the circuit 21. At least one of the printing condition and the plating condition is made different between the circuit 21 and the wiring 31 so as to be larger than the thickness of the conductor.

According to such a manufacturing method, the productivity of the flexible circuit with a cable is excellent, and the effect of excellent reliability of electrical connection can be obtained.

As an example of the case where the printing conditions are different between the circuit 21 and the wiring 31, the amount of ink applied in the printing method can be different. Specifically, in the printing method for forming the circuit 21 and the wiring 31, it is preferable that the amount of ink applied to the wiring 31 per unit area is larger than the amount of ink applied to the circuit 21 per unit area. ..

As an example of different plating conditions between the circuit 21 and the wiring 31, the plating time in electroplating or electroless plating can be made different, and the amount of plating current in electroplating can be made different. Specifically, in the plating process when forming the circuit 21 and the wiring 31, it is preferable that the plating time on the wiring 31 is longer than the plating time on the circuit 21. Further, in the plating process for forming the circuit 21 and the wiring 31, electrolytic plating is used, and the plating current amount per unit area of the wiring 31 is larger than the plating current amount per unit area of the circuit 21. It is preferable to do so.

Of the above-mentioned adjustments of the amount of ink applied, the plating time, and the amount of plating current, it is preferable to perform one or more adjustments, whereby the thickness of the conductor constituting the wiring 31 is efficiently configured in the circuit 21. It can be larger than the thickness of the conductor.

When the circuit 21 and the wiring 31 are formed by a printing method and a plating process, first, a conductor for forming the circuit 21 and the wiring 31 is patterned on the base material 1 by the printing method, and then the base material 1 is formed. It is preferable that the above conductor is plated to form the circuit 21 and the wiring 31.

The printing method and plating process will be described in more detail below.

[Printing method]
Examples of the printing method include a screen printing method, a letterpress printing method, an intaglio printing method, an offset printing method, a flexographic printing method, an inkjet method, and the like.

In the printing method, the thickness of the conductor can be adjusted by adjusting the amount of ink applied per unit area. By making the amount of ink applied to the wiring 31 per unit area larger than the amount of ink applied to the circuit 21 per unit area, the thickness of the conductor constituting the wiring 31 is made larger than the thickness of the conductor constituting the circuit 21. can do.

In the printing method, when the ink applied on the base material 1 is dried, the coffee stain phenomenon can be utilized to form a conductive thin wire made of a conductor. The conductive wire can be used to form the circuit 21 and / or the wiring 31. The coffee stain phenomenon will be described with reference to FIG.

First, as shown in FIG. 4A, a line-shaped liquid 4 made of ink containing a conductive material (conductor) is applied onto the base material 1.

Next, as shown in FIG. 4B, the conductive thin wire 5 can be formed by selectively depositing the conductive material on the edge of the linear liquid 4 in the process of drying the linear liquid 4. .. In this example, a pair of conductive thin wires 5 and 5 are formed by selectively depositing a conductive material on both edges of the linear liquid 4 along the longitudinal direction. By forming the line width of the line-shaped liquid 4 uniformly, a pair of conductive thin wires 5 and 5 can be formed in parallel with each other.

The line width of the conductive thin wire 5 is narrower than the line width of the linear liquid 4, preferably 10 μm or less, more preferably 7 μm or less, and most preferably 5 μm or less. The lower limit of the line width of the conductive thin wire 5 is not particularly limited, but can be set to, for example, 1 μm or more from the viewpoint of imparting stable conductivity. This preferable line width is also applied to the line width after plating, which will be described later.

Various patterns can be formed by the conductive thin wire 5. Examples of such a pattern include a stripe pattern and a mesh pattern (conductive thin wire mesh).

It is preferable to configure the sensor channel 22 described above by such a pattern, particularly a mesh pattern. The sensor channel 22 may be formed of a solid conductor, but the sensor channel 22 is an opaque conductor because the sensor channel 22 is formed of a stripe pattern or a mesh pattern so that light transmission is obtained through the gaps between the conductive thin lines. Can also be used to impart transparency to the sensor channel 22.

Hereinafter, the first aspect of mesh pattern formation will be described with reference to FIG. 5, and then the second aspect of mesh pattern formation will be described with reference to FIG.

In the first aspect of mesh pattern formation, first, as shown in FIG. 5A, a plurality of line-shaped liquids 4 arranged side by side at predetermined intervals are formed on the base material 1.

Next, as shown in FIG. 5B, a pair of conductive thin wires 5 and 5 are formed from each of the line-shaped liquids 4 by utilizing the coffee stain phenomenon when the line-shaped liquid 4 is dried.

Next, as shown in FIG. 5C, a plurality of line-shaped liquids 4 arranged side by side at predetermined intervals are formed so as to intersect with the plurality of conductive thin lines 5 formed earlier.

Next, as shown in FIG. 5D, a pair of conductive thin wires 5 and 5 are formed from each of the line-shaped liquids 4 by utilizing the coffee stain phenomenon when the line-shaped liquid 4 is dried. The mesh pattern can be formed as described above.

In the example of FIG. 5, the linear liquid 4 and the conductive thin wire 5 are straight lines, but the present invention is not limited to this. The shapes of the linear liquid 4 and the conductive thin wire 5 may be, for example, a wavy line or a broken line. Since the conductive thin wire 5 has a non-linear shape such as a wavy line or a broken line, the effect of preventing disconnection can be obtained even if the transparent conductor is curved.

In the second aspect of mesh pattern formation, first, as shown in FIG. 6A, the base material 1 is placed on the base material 1 in the longitudinal direction (vertical direction in the figure) and the width direction (horizontal direction in the figure). ) Are arranged side by side at predetermined intervals to form a line-shaped liquid 4 forming a plurality of quadrangles.

Next, as shown in FIG. 6B, when the line-shaped liquid 4 is dried, the coffee stain phenomenon is utilized to form a thin wire unit composed of a pair of conductive thin wires 5 and 5 from each of the line-shaped liquid 4. Form. In such a thin wire unit, one of the conductive thin wires 5 and 5 (outer conductive thin wire 5) includes the other (inner conductive thin wire 5) inside, and the conductive thin wires 5 and 5 are formed concentrically. Further, the conductive thin wires 5 and 5 each form a quadrangle corresponding to the shapes of both edges (inner peripheral edge and outer peripheral edge) of the linear liquid 4.

Next, as shown in FIG. 6C, a plurality of quadrangular line-shaped liquids 4 arranged side by side at predetermined intervals in the longitudinal direction and the width direction of the base material 1 are formed on the base material 1. Here, the line-shaped liquid 4 forming a plurality of quadrangles is formed at a position sandwiched between the previously formed thin wire units. Here, the linear liquid 4 forming a quadrangle is arranged so as to come into contact with the outer conductive thin wire 5 of the thin wire units adjacent thereto, but not to contact the inner conductive thin wire 5.

Next, as shown in FIG. 6D, when the line-shaped liquid 4 is dried, the coffee stain phenomenon is utilized to form a thin wire unit composed of a pair of conductive thin wires 5 and 5 from each of the line-shaped liquid 4. Further form.

In the pattern shown in FIG. 6D, the outer conductive thin wires 5 are connected to each other with the adjacent outer conductive thin wires 5. On the other hand, the inner conductive thin wire 5 is not connected to the other inner conductive thin wire 5 and the outer conductive thin wire 5. That is, the inner conductive thin wires 5 are arranged so as to be isolated.

The pattern shown in FIG. 6D may be used as it is as a mesh pattern. Further, the inner conductive thin wire 5 in the pattern shown in FIG. 6 (d) may be removed to form a mesh pattern (FIG. 6 (e)) composed of the outer conductive thin wire 5. According to the second aspect of mesh pattern formation, the effect of forming the conductive thin wire 5 with a high degree of freedom can be obtained. In particular, it is possible to obtain an effect that the arrangement interval of the plurality of conductive thin wires 5 can be set with a high degree of freedom without depending on the line width of the linear liquid 4.

The method for removing the inner conductive thin wire 5 is not particularly limited, and for example, a method of irradiating an energy ray such as a laser beam, a method of chemically etching, or the like can be used.

Further, when the outer conductive thin wire 5 is subjected to electrolytic plating described in detail later, a method of removing the inner conductive thin wire 5 with a plating solution may be used. As described above, the inner conductive thin wire 5 is arranged so as to be isolated, and can be excluded from the energization path for electroplating the outer conductive thin wire 5. Therefore, while the outer conductive thin wire 5 is electrolytically plated (while energized), the inner conductive thin wire 5 that is not electrolytically plated can be dissolved or decomposed and removed by the plating solution. it can.

As described above, a mesh pattern can be formed by combining a plurality of conductive thin wires 5 forming a quadrangle.

In the example of FIG. 6, the linear liquid 22 and the conductive thin line 5 are formed into a quadrangle, but the present invention is not limited to this. Examples of the shapes of the linear liquid 4 and the conductive thin wire 5 include a closed geometric figure. Examples of closed geometric figures include polygons such as triangles, quadrilaterals, hexagons, and octagons. Also, closed geometric figures can include curved elements such as circles, ellipses and the like.

Next, a printing method, particularly an ink preferably used for the above-mentioned coffee stain phenomenon, will be described in detail.

The ink can contain metal fine particles. Examples of the metal constituting the metal fine particles include Au, Pt, Ag, Cu, Ni, Cr, Rh, Pd, Zn, Co, Mo, Ru, W, Os, Ir, Fe, Mn, Ge, Sn, Ga, etc. In and the like can be mentioned. Among these, Au, Ag and Cu are preferable, and Ag is particularly preferable. The average particle size of the metal fine particles can be, for example, 1 to 100 nm, more preferably 3 to 50 nm. The average particle size is a volume average particle size and can be measured by "Zetasizer 1000HS" manufactured by Malvern.

The concentration of the metal fine particles in the ink can be, for example, 5% by weight or less, and further can be 0.01% by weight or more and 1.0% by weight or less. As a result, the coffee stain phenomenon is promoted, and the effect that the conductive thin wire can be further thinned can be obtained.

The solvent used for the ink is not particularly limited and may include one or more selected from water and organic solvents. Examples of the organic solvent include alcohols such as 1,2-hexanediol, 2-methyl-2,4-pentanediol, 1,3-butanediol, 1,4-butanediol, and propylene glycol, diethylene glycol monomethyl ether, and the like. Examples thereof include ethers such as diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether.

In addition, the ink may contain other components such as a surfactant. The surfactant is not particularly limited, and examples thereof include a silicon-based surfactant. The concentration of the surfactant in the ink can be, for example, 1% by weight or less.

The method for drying the ink (line-shaped liquid) applied on the substrate may be natural drying or forced drying. The drying method used for forced drying is not particularly limited, and for example, a method of heating the surface of the base material to a predetermined temperature, a method of forming an air flow on the surface of the base material, or the like can be used alone or in combination. .. The air flow can be formed by blowing or sucking air using, for example, a fan or the like.

The circuit 21 of the circuit unit 2 is composed of conductive thin wires formed by utilizing the coffee stain phenomenon described above, and the wiring 31 of the cable unit 3 is composed of a conductor formed without utilizing the coffee stain phenomenon. You may. In this case, it is preferable that the density (% by weight) of the conductor in the ink for forming the wiring 31 is higher than the concentration (% by weight) of the conductor in the ink for forming the circuit 21. As a result, the circuit 21 can be formed by promoting the coffee stain phenomenon with the relatively low-concentration ink, and the thickness of the conductor constituting the wiring 31 can be adjusted by the relatively high-concentration ink (the conductor constituting the circuit 21). It can be made larger than the thickness of the conductive thin wire).

In the above description, the case where the sensor channel 22 is composed of a plurality of conductive thin wires has been mainly described, but the present invention is not limited to this. The sensor channel 22 may be composed of, for example, a solid conductor. This also applies when the circuit 21 other than the sensor channel 22 is formed.

The conductor formed on the base material by the printing method can be fired. Examples of the firing treatment include light irradiation treatment and heat treatment. For the light irradiation treatment, for example, gamma rays, X-rays, ultraviolet rays, visible light, infrared rays (IR), microwaves, radio waves and the like can be used. For the heat treatment, for example, hot air, a heating stage, a heating press, or the like can be used.

[Plating]
As the plating process, for example, electroless plating, electrolytic plating and the like can be used. In electrolytic plating, the conductor can be selectively plated by utilizing the conductivity of the conductor (preferably having the form of a conductive thin wire) imparted on the base material in the printing process. By the plating process, a conductor composed of a printing layer made of a conductor formed by a printing method and a plating layer (plating film) covering the conductor can be obtained.

In both electroless plating and electrolytic plating, the thickness of the conductor can be adjusted by adjusting the plating time. When electrolytic plating is used, the thickness of the conductor can be adjusted by adjusting the amount of plating current per unit area.

The plating time can be adjusted by the immersion time in the plating solution.

For example, by making the immersion time of the wiring 31 of the cable portion 3 in the plating solution longer than the immersion time of the circuit 21 of the circuit portion 2 in the plating solution, the thickness of the conductor constituting the wiring 31 can be increased to form the circuit 21. It can be made larger than the thickness of the conductor to be plated.

The amount of plating current per unit area can be adjusted by the immersion time in the plating solution and / or the selection of the feeding portion.

For example, by making the immersion time of the wiring 31 of the cable portion 3 in the plating solution longer than the immersion time of the circuit 21 of the circuit portion 2 in the plating solution, the plating current per unit area of the wiring 31 of the cable portion 3 The amount can be made larger than the amount of plating current per unit area of the circuit unit 2 to the circuit 21. As a result, the thickness of the conductor constituting the wiring 31 can be made larger than the thickness of the conductor constituting the circuit 21.

The above-mentioned feeding portion is a portion where an electrode for electrolytic plating (usually a cathode) is brought into contact with the feeding portion, and the closer to the feeding portion, the larger the plating current amount per unit area. Therefore, for example, by selecting the wiring 31 of the cable unit 3 as the power feeding portion, the amount of plating current per unit area of the wiring 31 of the cable unit 3 can be determined by the plating current per unit area of the circuit 21 of the circuit unit 2. Can be larger than the amount. As a result, the thickness of the conductor constituting the wiring 31 can be made larger than the thickness of the conductor constituting the circuit 21.

The conductor provided on the base material in the printing process may be plated a plurality of times. The plating process may be performed a plurality of times with different plating metals. A plurality of metal layers (plating layers) can be laminated on the conductive thin wire by a plurality of plating processes. For example, when laminating a plurality of metal layers, the conductivity of Cu is improved by laminating the first metal layer made of Cu and the second metal layer made of Ni or Cr in order on the conductive thin wire made of Ag. The effect, the effect of improving the weather resistance by Ni or Cr, and the effect of eliminating the color can be obtained.

By making the number of plating processes applied to the wiring 31 of the cable portion 3 larger than the number of plating processes applied to the circuit 21 of the circuit unit 2, the thickness of the conductor constituting the wiring 31 can be reduced to the thickness of the conductor constituting the circuit 21. It may be larger.

3. 3. Flexible Circuit Intermediate with Cable The flexible circuit intermediate with cable of the present invention (hereinafter, also simply referred to as an intermediate) can be used as a material for manufacturing the flexible circuit with cable described above. For the intermediate, the description of the flexible circuit with cable and its manufacturing method is incorporated.

As shown in FIG. 7, the intermediate body is composed of a circuit unit 2 provided with a circuit 21 composed of conductors on at least one surface of the elongated flexible base material 1, and the circuit 21. A unit U composed of a cable portion 3 provided with a wiring 31 having one end electrically connected to and an other end for electrically connecting to an external circuit is formed in the longitudinal direction of the flexible base material 1. Multiple prints are made along the line.

As described above for the flexible circuit with a cable, the conductor constituting the circuit 21 and the conductor constituting the wiring 31 commonly contain at least one kind of metal. Further, the thickness of the conductor constituting the wiring 31 is larger than the thickness of the conductor constituting the circuit 21.

By cutting out the flexible base material 1 for each unit U from such an intermediate along the dotted line in FIG. 7, the above-mentioned flexible circuit with a cable can be manufactured.

According to such an intermediate, the productivity of the flexible circuit with a cable is excellent, and the effect of excellent reliability of electrical connection can be obtained.

At least one wiring 31 constituting the unit U, preferably all wirings 31 as shown in the example of FIG. 7, preferably extends from the circuit 21 toward the long side of the flexible base material 1. This has the effect of further improving productivity.

For example, in the case of laminating the protective material 4 on the circuit 21 and the wiring 31 so as to expose the other end of the wiring 31 in the intermediate, the protective layer composed of the protective layer 4 is carried while the intermediate is rolled to roll. It can be continuously laminated. At this time, since the wiring 31 extends toward the long side of the flexible base material 1, a constant lamination width L can be preferably set so that the other end of the wiring 31 is out of the lamination range.

1: Flexible base material 2: Circuit part 21: Circuit 22: Sensor channel 23: Drawer wiring 24: Aggregation part 3: Cable part 31: Wiring 4: Protective material

Claims (13)

On at least one surface of the flexible base material, there is a circuit portion provided with a circuit composed of conductors, and a wiring composed of conductors and having one end connected to the circuit and the other end for connecting to an external circuit. The provided cable part is printed,
The conductor constituting the circuit and the conductor constituting the wiring commonly contain at least one kind of metal.
The thickness of the conductor constituting the wiring is larger than the thickness of the conductor constituting the circuit.
The flexible base material includes a base material main body and a band-shaped portion extending in a band shape from the base material main body.
The circuit portion is provided on the base material main body, and the cable portion is provided on the strip-shaped portion.
A flexible circuit with a cable in which the other end of the wiring constituting the cable portion is provided at the tip of the strip-shaped portion. The flexible circuit with a cable according to claim 1, wherein the conductor constituting the circuit and the conductor constituting the wiring are alloys, respectively. The flexible circuit with a cable according to claim 2, wherein the alloy constituting the circuit and the alloy constituting the wiring commonly contain one or more selected from nickel, chromium, molybdenum, manganese and cobalt. The thickness of the conductor constituting the circuit is 0.05 μm to 10 μm.
The flexible circuit with a cable according to any one of claims 1 to 3, wherein the thickness of the conductor constituting the wiring is 1.5 to 10 times the thickness of the conductor constituting the circuit. The flexible circuit with a cable according to any one of claims 1 to 4, wherein a protective material is laminated on the circuit and the wiring so as to expose the other end of the wiring. The flexible circuit with a cable according to any one of claims 1 to 5, wherein the circuit is a touch sensor circuit composed of a plurality of sensor channels. The flexible circuit with a cable according to any one of claims 1 to 5, wherein the circuit is a heating element circuit that generates heat when energized. A manufacturing method for manufacturing a flexible circuit with a cable according to any one of claims 1 to 7.
When the circuit and the wiring are formed by combining the printing method and the plating process, the circuit and the wiring are formed so that the thickness of the conductor constituting the wiring is larger than the thickness of the conductor constituting the circuit. A method for manufacturing a flexible circuit with a cable, which makes at least one of printing conditions and plating conditions different. The cable according to claim 8, wherein in the printing method for forming the circuit and the wiring, the amount of ink applied to the wiring per unit area is larger than the amount of ink applied to the circuit per unit area. Flexible circuit manufacturing method. The method for manufacturing a flexible circuit with a cable according to claim 8 or 9, wherein in the plating process for forming the circuit and the wiring, the plating time for the wiring is longer than the plating time for the circuit. In the plating process for forming the circuit and the wiring, electrolytic plating is used, and the amount of plating current per unit area of the wiring is made larger than the amount of plating current per unit area of the circuit. Item 8. The method for manufacturing a flexible circuit with a cable according to any one of Items 8 to 10. A circuit portion provided with a circuit composed of conductors on at least one surface of a long flexible base material, one end formed of a conductor and connected to the circuit, and the other end for connecting to an external circuit. A plurality of units composed of a cable portion provided with wiring having a wire are printed along the longitudinal direction of the flexible base material.
The conductor constituting the circuit and the conductor constituting the wiring commonly contain at least one kind of metal.
A flexible circuit intermediate with a cable in which the thickness of the conductors constituting the wiring is larger than the thickness of the conductors constituting the circuit. The flexible circuit intermediate with a cable according to claim 12, wherein at least one of the wirings constituting the unit extends from the circuit toward the long side of the flexible base material.

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