WO2010050404A1

WO2010050404A1 - Fpc connection method for protective panels with touch input function

Info

Publication number: WO2010050404A1
Application number: PCT/JP2009/068225
Authority: WO
Inventors: 一登中村; 孝夫橋本; 和宏西川
Original assignee: 日本写真印刷株式会社
Priority date: 2008-10-31
Filing date: 2009-10-23
Publication date: 2010-05-06
Also published as: TW201031295A; JP2012014206A

Abstract

An FPC connection method for protective panels with touch input function, which is low cost and has a high degree of freedom in component mounting and materials selection, is characterized in that, when electrically connecting an FPC (10) to the lower circuit on a lower electrode panel and upper circuit on an upper electrode sheet of a protective panel with touch input function by means of through holes (9a‑9d) disposed in the lower electrode panel (3), a circuit is disposed on one surface of a film substrate, as well as a fill hole (10d) that passes through both the film substrate and the circuit is formed in the connection side edge, an insulating adhesive layer (23) is disposed on the connection side edge of the FPC, and the FPC is adhered to the bottom surface of the lower electrode panel by means of the insulating adhesive layer, and then the inside of a cavity (22) opposite the fill hole is filled with conductive adhesive (15) to electrically connect the FPC to the lower circuit and the upper circuit, after which, the conductive adhesive is cured in a state with the fill hole exposed, and lastly the fill hole is sealed with a sealing member.

Description

FPC connection method for protection panel with touch input function

The present invention is used for applications such as PDAs, portable terminals such as handy terminals, OA devices such as copiers and facsimiles, smartphones, mobile phones, portable game devices, electronic dictionaries, car navigation systems, small PCs, various home appliances, etc. The present invention relates to an FPC (Flexible-Printed-Circuit) connection method of a protection panel with a touch input function that is cost-effective and has a high degree of freedom in component mounting and material selection.

Generally, casings in electronic devices such as mobile phones and smartphones are configured by combining a front casing and a rear casing made of synthetic resin. Specifically, a protective panel is fixed to the surface of the front casing by fusion or the like in order to protect the liquid crystal display window. Conventionally, a colorless and transparent resin panel has been used as the protective panel. However, with the trend toward fashion of electronic devices, decoration such as bordering has been given by printing.

In recent years, a cellular phone is expected to have an input device function on the protection panel as shown in FIG. 8 as the next interface, which is disclosed in Patent Document 1, for example.

The protection panel with a touch input function 1 will be described in more detail with reference to the exploded view of FIG. In the figure, a protection panel 1 with a touch input function includes a lower electrode having a lower transparent electrode 5 and

lower circuits

7a and 7b provided around the lower transparent electrode 5 on the upper surface of a non-flexible protection panel body. An upper transparent electrode 4 provided at a position facing the lower transparent electrode 5 on the lower surface of the panel 3 and a flexible transparent insulating film, and upper circuits 6a to 6d, 7c provided around the upper

transparent electrode

4 , 7d, and a transparent window 18 formed by concealing the

lower circuits

7a, 7b and the upper circuits 6a-6d, 7c, 7d with a pattern 17 on a flexible transparent insulating film. And a decorative sheet 2b having a decorative layer.

On the inner surfaces of the upper electrode sheet 2a and the lower electrode panel 3, ITO (indium oxide / tin) or the like is formed in a rectangular shape as the

transparent electrodes

4 and 5 by sputtering or vacuum deposition. The upper electrode sheet 2a is formed with strip-shaped bus bars 6a and 6b using a silver paste connected to the transparent electrode 4, and the lower electrode panel 3 has a transparent electrode in a direction perpendicular to the bus bars 6a and 6b. Band-

shaped bus bars

7a and 7b using a silver paste connected to 5 are formed. Each of the

bus bars

6a, 6b, 7a, 7b has a circuit extending to the connecting portion 8 provided at the edge of the upper electrode sheet 2a, and is integrated into one place.

The decorative sheet 2b is bonded to the entire front surface of the upper electrode sheet 2a (hereinafter, a laminated film of the upper electrode sheet 2a and the decorative sheet 2b is referred to as a movable sheet 2), and the decorative sheet 2b is applied with a finger or a pen. When the surface of the decorative sheet 2b is pressed, the movable sheet 2 is integrally bent and downwards. As a result, the

transparent electrodes

4 and 5 formed on the inner surfaces of the upper electrode sheet 2a and the lower electrode panel 3 come into contact with each other. The input position is detected.

In FIG. 9, unlike the protective panel 1 with a touch input function described in Patent Document 1, the lower electrode panel 3 is penetrated corresponding to the

electrode ends

6 c, 7 c, 6 d, and 7 d in the connection portion 8. Holes 9a to 9d are formed in parallel to the Z direction. Then, four metal pins 11 to 14 are erected on the connection side end portion 10a of the FPC 10 corresponding to the through holes 9a to 9d, and the metal pins 11 to 14 are interposed via a conductive adhesive (not shown). The electrode ends 6c, 7c, 6d and 7d are electrically connected. A manufacturing method from the back surface of the lower electrode panel 3 is disclosed in Patent Document 2.

International Publication No. 2005/064451 Pamphlet International Publication No. 2006/077784 Pamphlet

In the FPC with a pin described in Patent Document 2, a metal pin fixing hole 10e is formed in a film base 10f and a circuit 10c as a conductive portion at a connection side end 10a of the FPC 10, and the metal pin fixing hole 10e is formed in the metal pin fixing hole 10e. From the circuit 10c side, metal pins 11 to 14 having a pin shaft portion and a head portion having a diameter larger than the outer diameter of the pin shaft portion are inserted to cover the head portions of the metal pins 11 to 14. Thus, the coverlay film 10b is stuck on the circuit 10c and the film substrate 10f (see FIG. 10).

However, the FPC with a pin is expensive to process the metal pin.

Also, the FPC with pins has a problem that it is difficult to mount components such as BtoB (Board-to-Board) connectors and IC chips. That is, when printing a solder paste for mounting a component on the circuit of the FPC, the metal pin is erected at the connection side end of the FPC, which is an obstacle to printing. For example, a screen plate or a squeegee of a screen printing apparatus hits the metal pin during printing.

In addition, the great advantage of the FPC with a pin is that an ultrasonic insert method with high FPC connection strength to the lower electrode panel can be used (the ultrasonic insert method applies ultrasonic vibration and pressure). By inserting the pin shaft portion of the metal pin into the through hole of the lower electrode panel, local frictional heat is generated on the wall surface of the through hole, and the pin shaft portion is moved while melting the wall surface. And the pin shaft portion is fixed to the lower electrode panel by re-solidification of the wall surface).

However, the ultrasonic insert method can be applied only to a part of the material of the protective panel body conventionally used for the lower electrode panel of the protective panel with a touch input function.

For example, the ultrasonic insert method cannot be applied to a thin protective panel that cannot secure a thickness for fixing the pin shaft stably.

The present invention provides an FPC connection method for a protection panel with a touch input function that is low in cost and has a high degree of freedom in component mounting and material selection in consideration of the above-described problems of the prior art.

According to the present invention, an upper electrode sheet having an upper transparent electrode and an upper circuit is disposed opposite to a lower electrode panel having a lower transparent electrode and a lower circuit, and the transparent window is formed in a state of concealing the lower circuit and the upper circuit. In the method of electrically connecting the FPC to the lower circuit and the upper circuit for the protective panel with a touch input function provided with the decorative sheet to be formed,
A through hole for electrically connecting the lower circuit, the upper circuit, and the FPC is formed in the lower electrode panel,
A hole for filling is formed through the film base at the connection side end of the FPC and the circuit formed on one side thereof,
An insulating adhesive layer is provided at the connection side end of the FPC,
Positioning the FPC and the lower electrode panel so that the through hole and the filling hole communicate with each other;
Adhering the FPC to the lower surface of the lower electrode panel via the insulating adhesive layer,
Injecting a conductive adhesive into a cavity that includes the through hole and extends from the filling hole to the through hole,
The gist is to cure the conductive adhesive in a state of being exposed in the filling hole.

In the present invention, the lower electrode panel has a lower transparent electrode on the upper surface of the protective panel body and a lower circuit provided around the lower transparent electrode,
The electrode sheet has, on the lower surface of a flexible transparent insulating film, an upper transparent electrode provided at a position facing the lower transparent electrode and an upper circuit provided around the upper transparent electrode,
The gist of the decorative sheet is that a decorative layer is formed on at least one surface of a flexible transparent insulating film and is bonded to the upper surface of the upper electrode sheet.

Moreover, in this invention, when the said conductive adhesive is what disperse | distributed the conductive filler in the thermosetting resin paste, the said conductive adhesive is hardened by heating through the said hole for filling. Can be made.

In the present invention, when the conductive adhesive is obtained by dispersing a conductive filler in a moisture curable resin paste, the conductive adhesive is cured by absorbing moisture through the filling hole. Can be made.

Moreover, in this invention, when the said conductive adhesive is what disperse | distributed the conductive filler in the solvent volatile resin paste, the said conductive adhesive is hardened by heating through the said hole for filling. Can be made.

In the present invention, an electronic component can be mounted on the FPC, for example, a COF (Chip-on-Film).

In the present invention, the protective panel body can be composed of a glass plate.

Further, the cavity facing the filling hole is formed by a connection side end of the FPC, a lower surface of the lower electrode panel, and a through hole provided in the lower electrode panel.

According to the present invention, the FPC for connection is provided with a circuit on one side of the film base material, and a filling hole penetrating both the film base material and the circuit at the connection side end. Because it is not pinned, it has the following effects. That is, since high-cost metal pin processing is not performed, the touch window can be connected at low cost, and there are no standing pins that obstruct the printing of solder paste, so that components such as BtoB connectors and IC chips are mounted. In addition, since it is not fixed by pin insertion, it is possible to construct a touch window that uses a glass support plate as a lower electrode panel to which the ultrasonic insert method cannot be applied, and is provided on the pin and the glass support plate. It is also possible to eliminate cracks in the glass support plate that occur when the position accuracy of the holes is low.

Furthermore, an insulating adhesive layer is provided at the connection side end of the FPC leaving the periphery of the filling hole, and the FPC is adhered to the lower surface of the lower electrode panel by the insulating adhesive layer. A state where the FPC is electrically connected to the lower circuit and the upper circuit by filling the cavity facing the filling hole with the conductive adhesive, and then the conductive adhesive is exposed to the filling hole Therefore, there is an advantage that the adhesive strength of the conductive portion is improved and the reliability in energization is obtained. Further, deformation and deterioration of the FPC can be prevented.

It is a principal part expanded sectional view which shows the FPC connection process of the protection panel with a touch input function which concerns on this invention. It is a principal part expanded sectional view which shows the FPC connection process of the protection panel with a touch input function which concerns on this invention. It is a principal part expanded sectional view which shows the FPC connection process of the protection panel with a touch input function which concerns on this invention. It is a principal part expanded sectional view which shows the FPC connection process of the protection panel with a touch input function which concerns on this invention. It is a disassembled perspective view which shows the basic composition except FPC of the protection panel with a touch input function which concerns on this invention. It is a perspective view which shows FPC used by this invention. It is a principal part expanded sectional view which shows the connection structure at the time of using FPC in which the hole for filling is not drilled. It is a disassembled perspective view which shows the example of application of the protection panel with a touch input function of this invention. It is a disassembled perspective view which shows the structure of the protection panel with a touch input function which concerns on a prior art. It is a principal part expanded sectional view which shows the FPC connection structure of the protection panel with a touch input function which concerns on a prior art.

Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 5 is an exploded perspective view showing a basic configuration excluding the FPC 10 of the protection panel 1 with a touch input function.

In the figure, a protection panel 1 with a touch input function includes a lower electrode having a lower transparent electrode 5 and

lower circuits

transparent electrode

4 , 7d, and a transparent window 18 formed by concealing the

lower circuits

7a, 7b and the upper circuits 6a-6d, 7c, 7d with a pattern 17 on a flexible transparent insulating film. The decorative sheet 2b having a decorative layer is provided.

Examples of the material of the inflexible protective panel body of the lower electrode panel 3 include glass plates, engineering plastics such as polycarbonate, polyamide, and polyether ketone, acrylic, polyethylene terephthalate, and polybutylene terephthalate. A plastic plate or the like of a system can be used. Moreover, engineering plastics such as polycarbonate, polyamide, or polyetherketone, acrylic, polyethylene terephthalate, or polybutylene terephthalate are pasted on the surface of these plates where the lower transparent electrode is to be formed. The lower electrode panel 3 may be used.

Examples of the material of the flexible transparent insulating film of the upper electrode sheet 2a include engineering plastics such as polycarbonate, polyamide, or polyether ketone, acrylic, polyethylene terephthalate, or polybutylene. A terephthalate film or the like can be used.

The upper electrode sheet 2a and the lower electrode panel 3 are arranged to face each other so as to form a gap between the

transparent electrodes

4 and 5, and are bonded to each other at the peripheral edge. The

transparent electrodes

4 and 5 are mainly composed of metal oxide films such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), or these metal oxides. A composite film or a metal film such as gold, silver, copper, tin, nickel, aluminum, or palladium is formed in a rectangular shape by a vacuum evaporation method, sputtering, ion plating, or CVD method.

The upper electrode sheet 2a is a strip-shaped bus bar 6a, 6b using a conductive paste such as a metal such as gold, silver, copper, or nickel, or carbon connected to the upper transparent electrode 4 as an upper circuit. Are formed in parallel, and the lower electrode panel 3 is formed with strip-

like bus bars

7a, 7b orthogonal to the bus bars 6a, 6b as the lower transparent electrode 5 and the lower circuit. The strip-shaped

bus bars

6a, 6b, 7a, and 7b can be formed by a printing method such as screen printing, offset printing, gravure printing, or flexographic printing, a photoresist method, or a brush coating method.

In addition, each

bus bar

6a, 6b, 7a, 7b has a circuit extended to the connection part 8 provided in the edge part of the upper electrode sheet 2a, and is put together in one place. In FIG. 5, the bus bars 6a and 6b of the upper electrode sheet 2a are extended to the electrode ends 6d and 6c of the connecting portion 8, and the lower circuit is extended from the bus bars 7a and 7b of the lower electrode panel 3 by the portion 7e. , 7f are connected to the electrode ends 7c, 7d formed on the connecting portion 8 of the upper electrode sheet 2a along with the electrode ends 6d, 6c by a conductive adhesive (not shown).

Through holes 9a to 9d are formed in the lower electrode panel 3 so as to correspond to the electrode ends 6c, 7c, 6d, and 7d in the connecting portion 8.

Further, a decorative sheet 2b having a transparent window 18 is bonded to the surface of the upper electrode sheet 2a. The decorative sheet 2b is a flexible transparent insulating film such as polycarbonate, polyamide or polyether ketone engineering plastic, acrylic, polyethylene terephthal or polybutylene terephthal. A decorative layer is formed with a pattern 17 so as to conceal the periphery of the transparent window 18, that is, the upper circuit, the lower circuit, and the like on one side.

The decorative layer is made of a resin such as polyvinyl resin, polyamide resin, polyester resin, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, or alkyd resin, and is used as a binder. Colored inks containing color pigments or dyes as colorants may be used. As a method for forming the decorative layer, a normal printing method such as screen printing, offset printing, gravure printing, or flexographic printing may be used. In particular, the offset printing method and the gravure printing method are suitable for performing multicolor printing and gradation expression.

Further, the decorative layer may be composed of a metal thin film layer or a combination of a pattern printing layer and a metal thin film layer. The metal thin film layer expresses metallic luster as the decorative layer, and is formed by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like.

In this case, a metal such as aluminum, nickel, gold, platinum, chromium iron, copper, tin, indium, silver, titanium, lead, or zinc, or an alloy or compound thereof is used depending on the metallic luster color to be expressed. use. The film thickness of the metal thin film layer is generally about 0.05 μm.

The decorative sheet 2b is bonded to the entire front surface of the upper electrode sheet 2a to constitute the movable sheet 2. When the surface of the decorative sheet 2b is pressed with a finger or a pen, the movable sheet 2 is integrally bent downward, and as a result, each transparent electrode 4 formed on the inner surface of the lower electrode panel 3 extending over the upper electrode sheet 2a. , 5 are contacted to detect the input position. As the adhesive layer used for bonding, for example, a polyacrylic resin, a polystyrene resin, a polyamide resin, vinyl chloride, vinyl acetate, or an acrylic copolymer may be used. As a method for forming the adhesive layer 5d, a normal printing method such as screen printing, offset printing, gravure printing, or flexographic printing may be used.

The basic configuration of the protection panel 1 with a touch input function of the electronic device display window has been described above. The feature of the present invention is that the through-hole provided in the lower electrode panel 3 with respect to the protection panel 1 with a touch input function. This is a method for electrically connecting the FPC 10 to the lower circuit and the upper circuit through 9a to 9d, and the following steps (FIGS. 1 to 4) are performed.

[First Embodiment]
First, as the FPC 10, a circuit 10c is provided on one surface of a film substrate 10f, and a filling hole 10d penetrating both the film substrate 10f and the circuit 10c is formed in a connection side end 10a. Is prepared (see FIG. 6).

Normally, as shown in FIG. 6, the FPC has a film base 10f having a circuit 10c covered with a coverlay film 10b for protecting and insulating the conductor circuit 10c. Is not covered because it needs to be connected to the electrode end, exposing the circuit 10c.

As the film substrate 10f and the coverlay film 10b, for example, a flexible insulating film such as polyimide cage (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN) can be used. The circuit 10c is formed using a metal such as gold, silver, copper, or nickel, or a conductive paste such as carbon. As a method for forming the circuit 10c, a printing method such as screen printing, offset printing, gravure printing, or flexographic printing, a photoresist method, or the like can be used. Further, as a means for forming the filling hole 10d, a drill method or the like can be used.

An insulating adhesive layer 23 is provided on the connection side end 10a of the FPC 10 so as to leave the periphery of the filling hole 10d, and is adhered to the lower surface of the lower electrode panel 3 by the insulating adhesive layer 23 (see FIG. 1).

The space between the connection side end 10a of the bonded FPC 10 and the lower surface of the lower electrode panel 3, and the through holes 9a to 9d provided in the lower electrode panel 3, the filling hole 10d. A cavity 22 is formed facing the surface.

Each region surrounded by the insulating adhesive layer 23 is formed to be slightly larger than each of the through holes 9a to 9d provided in the lower electrode panel 3, so that the bonding position of the FPC 10 is shifted. That is, even when the bonding positions of the regions surrounded by the insulating adhesive layer 23 and the through holes 9a to 9d are deviated, the reliability of electrical connectivity can be obtained. As the insulating adhesive layer 23, a frame-shaped double-sided tape in which the filling hole 10d is punched can be used. In place of the double-sided tape, an insulating adhesive such as water-based or acrylic printing paste may be used.

In addition, 16 in FIG. 1 is an adhesive layer for bonding the upper electrode sheet 2a of the movable sheet 2 and the lower electrode panel 3 around. In the adhesive layer 16, it is necessary to form connection holes for injecting the conductive adhesive 15 corresponding to the electrode ends 6 c, 7 c, 6 d, 7 d in the connection part 8. As the adhesive layer 16, for example, a frame-like double-sided tape in which at least the connection holes (the transparent window 18 in FIG. 5) and the connection holes are punched out can be used. In place of the double-sided tape, an insulating adhesive, for example, an aqueous, acrylic or hot-melt printing paste may be used.

Next, a conductive adhesive 15 is filled in the cavity 22 facing the filling hole 10d to electrically connect the FPC 10 to the lower circuit and the upper circuit (see FIG. 2).

As the conductive adhesive 15 filled in the cavity 22, a thermosetting conductive adhesive can be used. The thermosetting conductive adhesive is obtained by dispersing a conductive filler in a thermosetting resin paste. When heated, the curing progresses, and the cured molecules generally form a three-dimensional network.

Examples of the thermosetting resin include those made of thermosetting resin components such as (meth) acrylic compounds, acrylic resins, urethane compounds, urethane resins, unsaturated polyester resins, epoxy compounds, epoxy resins, and phenol resins. can do. Furthermore, the form of the curing reaction of the thermosetting resin may be any polymerization form such as radical polymerization of double bonds, ionic polymerization of epoxy resin, or polyaddition.

In addition to conductive metal powders such as silver, gold, copper, nickel, platinum, and palladium, the conductive filler includes inorganic insulators such as alumina and glass as core materials, and organic materials such as polyethylene, polystyrene, and divinylbenzene. Examples thereof include a polymer, etc., the core material surface of which is coated with a conductive layer such as gold and nickel, carbon, graphite and the like. In addition, the conductive filler may have a flake shape, a spherical shape, a short fiber shape, or the like. Examples of the method for filling the conductive adhesive 15 include a dispenser method.

Next, the conductive adhesive 15 is cured while being exposed to the filling hole 10d (see FIG. 3). In the figure, 24 is a conductive adhesive after curing.

The FPC is electrically connected in the usual manner using the thermosetting conductive adhesive, that is, the filling hole 10d is commercially available after the thermosetting conductive adhesive is applied as shown in FIG. If the FPC that is not bonded is fixed, the curing basically depends on heat conduction, the FPC becomes an obstacle, the curing rate is slow and the production rate cannot be increased, and further the adhesive strength of the conductive part is not cured to the inside. There is a problem that the electrical reliability cannot be obtained inside without improving. Further, deformation and deterioration due to heat of the FPC are inevitable. In addition, if it takes time for heating after the application of the thermosetting conductive adhesive to cure the inside, the FPC may be cured before being fixed, and the FPC may not be conductively bonded.

In the present invention, since the thermosetting conductive adhesive is exposed in the filling hole 10d, the adhesive can be directly heated through the filling hole 10d, and curing is promoted. Cures quickly to the inside. Therefore, compared with the structure of the preceding paragraph, there exists an advantage that the adhesive strength of an electroconductive part improves and electrical reliability is acquired also inside. In addition, since the adhesive can be directly heated, the influence of heat on the FPC is small, and deformation and deterioration of the FPC can be prevented. In addition, since the FPC having the filling hole 10d is fixed to the lower surface of the lower electrode panel, the thermosetting conductive adhesive is filled and cured in the cavity 22 facing the filling hole 10d. The conductive adhesion with the FPC is sufficient.

Finally, the filling hole 10d is sealed with a sealing material 21 (see FIG. 4). For example, the sealing material 21 is made of a thermosetting resin component such as a (meth) acrylic compound, an acrylic resin, a urethane compound, a urethane resin, an unsaturated polyester resin, an epoxy compound, an epoxy resin, or a phenol resin. Can do. Sealing after curing of the conductive adhesive 15 has the purpose of ensuring insulation and preventing deterioration. As a means for sealing the filling hole 10d using these sealing materials 21, there is a dispenser method or the like.

<Example 1>
An ITO film having a thickness of 20 nm was formed on one surface of a PET film having a thickness of 0.1 mm by sputtering, and the peripheral portion of the ITO film was removed to obtain a transparent electrode having a wide rectangular shape. Also, bus bars arranged on two sides facing the transparent electrode in the lateral direction and lead lines for outputting to the outside from the bus bars were formed by screen printing of silver paste. In addition, after an acrylic plate having the same dimensions as the PET film and having a thickness of 0.7 mm is bonded to the surface of the PET film opposite to the surface on which the transparent electrode is formed, with a baseless transparent adhesive having a thickness of 0.025 mm The lower electrode panel was obtained by puncturing four 1.5 mm through holes by a drill method.

Also, using a PET film with the same vertical and horizontal dimensions as the lower electrode panel and a thickness of 125 μm, an ITO film with a thickness of 20 nm is formed on the entire surface by sputtering, and the peripheral portion of the ITO film is removed to form a wide rectangular shape. A transparent electrode was obtained. Further, a bus bar arranged on two sides facing the vertical direction of the transparent electrode and a lead-out line (thickness 35 μm) to be output from the bus bar to the outside are finely flaky silver powder (diameter in a binder made of polyester resin. A silver paste containing a large number of conductive fillers of 10 μm) was formed by screen printing to obtain an upper electrode sheet.

Furthermore, using a PET base material hard coat film with the same dimensions as the lower electrode panel and a thickness of 0.075 mm, a decorative layer having a transparent window on the opposite side of the hard coat surface is formed by gravure printing. A decorative sheet was obtained. Thereafter, the surface of the decorative sheet on the side of the decorative layer was bonded to the surface opposite to the transparent electrode side of the upper electrode sheet with a baseless transparent adhesive having a thickness of 0.025 mm to obtain a movable sheet.

Next, the lower electrode panel and the movable sheet are arranged to face each other so as to separate the electrodes formed on each other, and a frame-shaped double-sided adhesive tape (thickness 50 μm) in which a transparent window portion and front connection holes are punched out And cut along the inner periphery of the decorative layer.

On the other hand, four filling holes with a diameter of 1 mm were drilled by the drill method at the connection side end of the FPC formed by forming a circuit as a conductive part with silver paste on one surface of a polyimide film having a thickness of 0.075 mm. Furthermore, the circuit of the FPC and the head of the metal pin are covered except for the connection side end. A polyimide film with a thickness of 0.05 mm is attached. An FPC with holes for filling was obtained.

Next, an insulating adhesive layer made of a polyester resin was provided by a screen printing method while leaving the periphery of the filling hole (diameter 1.6 mm) at the connection side end of the FPC. This was overlaid on the lower surface of the lower electrode panel so that the filling hole corresponded to the through hole, and was bonded and fixed by the insulating adhesive layer.

Next, the cavity facing the filling hole was filled with a thermosetting conductive adhesive ink with a dispenser, and the FPC was electrically connected to the lower circuit and the upper circuit. This thermosetting conductive adhesive is obtained by mixing flaky silver powder having a particle size of 10 μm in a binder made of an acrylic resin.

Next, the thermosetting conductive adhesive was cured by direct heating in a state where the thermosetting conductive adhesive was exposed in the filling hole.

Finally, a sealing material made of acrylic resin was applied to the filling hole with a dispenser, and the filling hole was sealed to complete the FPC connection to the protection panel with a touch input function.

[Second Embodiment]
Further, as the conductive adhesive 15 filled in the cavity 22, a moisture curable conductive adhesive can be used instead of the thermosetting conductive adhesive of the first embodiment. The moisture curable conductive adhesive is obtained by dispersing a conductive filler in a moisture curable resin paste, the curing reaction is accelerated in the presence of moisture, and the adherend is bonded and fixed. Unlike the first embodiment, heating is not necessary.

The moisture curable resin includes a silicone adhesive, a modified silicone adhesive, a urethane adhesive, and the like. The material of the conductive filler and the filling method of the conductive adhesive 15 are the same as in the first embodiment.

The FPC is electrically connected in the usual manner using the moisture curable conductive adhesive, that is, the commercially available filling hole 10d is provided after the moisture curable conductive adhesive is applied as shown in FIG. When an FPC that is not bonded is bonded and fixed, it takes time for moisture to penetrate into the moisture curable conductive adhesive due to the FPC becoming an obstacle, or the vicinity of the FPC side of the moisture curable conductive adhesive is It hardens quickly due to moisture, and afterwards it becomes difficult for moisture to penetrate inside, so the inside remains uncured for a long time, and the adhesive strength of the conductive part does not improve, and electrical reliability is obtained inside The problem arises. In addition, if it takes time for moisture absorption after application of the moisture-curable conductive adhesive to cure the inside, it may be cured before fixing the FPC, and conductive adhesion with the FPC may not be possible.

In the present invention, since the moisture-curing conductive adhesive is exposed in the filling hole 10d, moisture existing in the air can reach the adhesive through the filling hole 10d and is cured. Is accelerated and hardens quickly to the inside. Therefore, compared with the structure of the preceding paragraph, there exists an advantage that the adhesive strength of an electroconductive part improves and electrical reliability is acquired also inside. In addition, after the FPC having the filling hole 10d formed therein is fixed to the lower surface of the lower electrode panel, the moisture curable conductive adhesive is filled and cured in the cavity 22 facing the filling hole 10d. The conductive adhesion with the FPC is sufficient.

<Example 2>
In place of the thermosetting conductive adhesive described in Example 1, a moisture curable conductive adhesive is filled, and the moisture curable conductive adhesive is exposed to the filling hole by moisture absorption. The procedure was the same as Example 1 except that it was cured. This moisture curable conductive adhesive is obtained by mixing a flaky silver powder having a particle size of 10 μm in a binder made of a silicone resin.

[Third Embodiment]
As another conductive adhesive 15 filled in the cavity 22, a solvent volatile conductive adhesive can be used instead of the thermosetting conductive adhesive of the first embodiment. The solvent volatile conductive adhesive is obtained by dispersing a conductive filler in a solvent volatile resin paste, and by volatilizing the solvent, the curing reaction is promoted to adhere and fix the adherend. Examples of the solvent volatile resin include polyether polyol / polyisocyanate adhesive and polyester polyol / polyisocyanate adhesive. The material of the conductive filler and the filling method of the conductive adhesive 15 are the same as in the first embodiment.

The FPC is electrically connected in the usual manner using the solvent volatile conductive adhesive, that is, as shown in FIG. 7, the commercially available filling hole 10d is provided after the solvent volatile conductive adhesive is applied. If an unfixed FPC is bonded and fixed, the FPC becomes an obstacle and it takes time for the solvent to evaporate, or the solvent remains and remains uncured for a long period of time. A problem arises in that it is not possible to obtain reliable reliability. Furthermore, since the solvent volatile conductive adhesive has a volume shrinkage during curing, or due to outgassing, avoid deformation and deterioration of the FPC in contact with the solvent volatile conductive adhesive. I can't. Further, if it takes time for moisture absorption after the application of the solvent volatile conductive adhesive to cure, it may be cured before bonding the FPC, and the FPC may not be conductively bonded.

In the present invention, since the solvent volatile conductive adhesive is exposed in the filling hole 10d, the solvent can be volatilized through the filling hole 10d, and the curing is promoted to the inside. Cures quickly. Therefore, compared with the structure of the preceding paragraph, there exists an advantage that the adhesive strength of an electroconductive part improves and electrical reliability is acquired also inside. Moreover, even if the volume shrinks during the curing, the FPC filling hole 10d is not in contact with the solvent volatile conductive adhesive, so the influence of the shrinkage on the FPC is small, and the outgas is also the above-mentioned Since it comes out of the filling hole 10d, deformation and deterioration of the FPC can be prevented. Since the FPC having the filling hole 10d formed therein is fixed to the lower surface of the lower electrode panel, the solvent volatile conductive adhesive is filled and cured in the cavity 22 facing the filling hole 10d. The conductive adhesion with the FPC is sufficient.

In any case of the first embodiment to the third embodiment, the FPC connection method of the present invention does not perform high-cost metal pin processing. FPC can be connected at low cost. Further, since there are no standing pins that obstruct the printing of the solder paste, it is easy to mount components such as a BtoB connector and an IC chip. Furthermore, since the FPC connection method of the present invention is not fixed by inserting pins, the FPC can be connected to a protection panel with a touch input function using a glass support plate for the lower electrode panel.

<Example 3>
In place of the thermosetting conductive adhesive described in Example 1, a solvent volatile conductive adhesive is filled, and the solvent volatile conductive adhesive is exposed in the filling hole and dried ( Example 1 except that it was cured by solvent volatilization. This solvent volatile conductive adhesive is obtained by mixing flaky silver powder having a particle size of 10 μm in a binder made of polyester polyol resin.

The above-mentioned protective panels with a touch input function of Examples 1 to 3 were all low in cost, highly flexible in component mounting and material selection, and further excellent in FPC connection reliability.

It should be noted that, by appropriately combining arbitrary embodiments among the various embodiments, the effects possessed by them can be produced. Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various variations and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as long as they do not depart from the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention is used for display units of PDAs, handy terminals and other portable information terminals, copiers, OA devices such as facsimiles, smartphones, mobile phones, portable game devices, electronic dictionaries, car navigation systems, small PCs, and various household appliances Can do.

DESCRIPTION OF SYMBOLS 1 Protection panel with a touch input function 2 Movable sheet 2a Upper electrode sheet 2b Decorating sheet 3 Lower electrode panel 4 Upper transparent electrode 5 Lower transparent electrode 6a, 6b Bus bar 6c,

6d Electrode end

7a,

7b Bus bar

7c,

7d Electrode end

7e, 7f Circuit extended from bus bar 8 Connection portion 9a to 9d Through hole 10 FPC
10a Connection side end 10b Coverlay film 10c Circuit 10d Filling hole 10e Metal pin fixing hole 10f Film base 11-14 Metal pin 14a Pin head 15 Conductive adhesive 16 Adhesive layer 17 Picture 18 Transparent window part 19 Product 20 Display 21 Sealing material 22 Cavity 23 Insulating adhesive layer 24 Conductive adhesive (after curing)

Claims

Decorating the lower electrode panel having the lower transparent electrode and the lower circuit with the upper electrode sheet having the upper transparent electrode and the upper circuit facing each other and forming a transparent window portion in a state of concealing the lower circuit and the upper circuit In a method of electrically connecting an FPC to the lower circuit and the upper circuit for a protective panel with a touch input function provided with a sheet,
A through hole for electrically connecting the lower circuit, the upper circuit, and the FPC is formed in the lower electrode panel,
A hole for filling is formed through the film base at the connection side end of the FPC and the circuit formed on one side thereof,
An insulating adhesive layer is provided at the connection side end of the FPC,
Positioning the FPC and the lower electrode panel so that the through hole and the filling hole communicate with each other;
Adhering the FPC to the lower surface of the lower electrode panel via the insulating adhesive layer,
Injecting a conductive adhesive into a cavity that includes the through hole and extends from the filling hole to the through hole,
An FPC connection method for a protection panel with a touch input function, wherein the conductive adhesive is cured in a state where the conductive adhesive is exposed in the filling hole.
The lower electrode panel has a lower transparent electrode on the upper surface of the protective panel body and a lower circuit provided around the lower transparent electrode,
The electrode sheet has, on the lower surface of a flexible transparent insulating film, an upper transparent electrode provided at a position facing the lower transparent electrode and an upper circuit provided around the upper transparent electrode,
2. The protection panel with a touch input function according to claim 1, wherein the decorative sheet has a decorative layer formed on at least one surface of a flexible transparent insulating film and is bonded to the upper surface of the upper electrode sheet. FPC connection method.
2. The FPC connection method of a protection panel with a touch input function according to claim 1, wherein the conductive adhesive is cured in a state of being exposed to the filling hole, and then the filling hole is sealed with a sealing material.
The conductive adhesive is obtained by dispersing a conductive filler in a thermosetting resin paste, and the conductive adhesive is cured by heating through the filling hole. FPC connection method for protection panel with touch input function.
The conductive adhesive is obtained by dispersing a conductive filler in a moisture-curable resin paste, and the conductive adhesive is cured by absorbing moisture through the filling hole. FPC connection method for protection panel with touch input function.
The conductive adhesive is obtained by dispersing a conductive filler in a solvent volatile resin paste, and the conductive adhesive is cured by heating through the filling hole. FPC connection method for protection panel with touch input function.
The FPC connection method for a protection panel with a touch input function according to claim 1, wherein an electronic component is mounted on the FPC.
The FPC connection method for a protection panel with a touch input function according to claim 1, wherein the protection panel body is made of a glass plate.