JP2012014206A - Fpc connection method for protection panel with touch input function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FPC connection method for a protection panel with a touch input function at a low cost and with a high degree of freedom in component packaging or material selection.SOLUTION: The present invention relates to a method for electrically connecting an FPC with a lower circuit and an upper circuit via a through-hole provided in a lower electrode panel for a protection panel with a touch input function. In the FPC, a circuit is provided on one side of a film substrate, and a charging hole passing through both the film substrate and the circuit is opened at a connecting-side terminal portion. In the connecting-side terminal portion of the FPC, an insulated adhesive layer is provided while leaving the surroundings of the charging hole, the FPC is adhered to a lower surface of the lower electrode panel by the insulated adhesive layer, the FPC is then electrically connected with the lower circuit and the upper circuit by charging the inside of a cavity facing the charging hole with a conductive adhesive, and after the conductive adhesive is cured while being exposed to the charging hole, the charging hole is finally sealed by a sealing material.

Description

  The present invention is used for applications such as PDAs, handheld terminals and other portable information terminals, copiers, facsimiles and other OA devices, smartphones, mobile phones, portable game devices, electronic dictionaries, car navigation systems, small PCs, and various household appliances. The present invention relates to an FPC connection method for 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.

  A casing in an electronic device such as a mobile phone or a smartphone is generally 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, for example, Patent Document 1.

  The protection panel 1 with a touch input function will be described in more detail using 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. And corresponding to these through-holes 9a-9d, the four metal pins 11-14 are standingly arranged by the connection side edge part 10a of FPC (flexible printed wiring board) 10, and the said metal pins 11-14 are not shown in figure. The electrode ends 6c, 7c, 6d, and 7d are electrically connected through a conductive adhesive. 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 formed to have 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.

  Moreover, the FPC with a pin has a problem that it is difficult to mount components such as a BtoB connector and an IC chip. 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.

  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 protective panel body material conventionally used for the lower electrode panel of the protective panel with a touch input function.

  Accordingly, 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.

The present invention comprises a lower electrode panel having a lower transparent electrode and a lower circuit provided around the lower transparent electrode on the upper surface of the inflexible protective panel body;
An upper transparent electrode provided at a position opposite to the lower transparent electrode on the lower surface of the flexible transparent insulating film, and an upper circuit provided around the upper transparent electrode; and between the lower electrode panel and the electrode An upper electrode sheet bonded at the peripheral edge so as to form a gap,
A decorative sheet that has a decorative layer that conceals the lower circuit and the upper circuit to form a transparent window on at least one surface of a flexible transparent insulating film, and is bonded to the upper surface of the upper electrode sheet; ,
A protective panel with a touch input function comprising: electrically connecting the FPC to the lower circuit and the upper circuit through a through hole provided in the lower electrode panel,
In the FPC, a circuit is provided on one side of the film base material, and a filling hole penetrating both the film base material and the circuit is formed at the connection side end,
An insulating adhesive layer is provided to leave the periphery of the filling hole at the connection-side end portion of the FPC, and is adhered to the lower surface of the lower electrode panel by the insulating adhesive layer.
Next, a conductive adhesive is filled in the cavity facing the filling hole to electrically connect the FPC to the lower circuit and the upper circuit,
Next, after curing with the conductive adhesive exposed in the filling hole,
Finally, the filling hole was configured to be sealed with a sealing material.

  Further, in the above configuration, 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. I tried to make it.

  Further, in the above configuration, the conductive adhesive is formed by dispersing a conductive filler in a moisture curable resin paste, and the conductive adhesive is cured by absorbing moisture through the filling hole. I tried to make it.

  Further, in the above configuration, 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. I tried to make it.

  Moreover, in each said structure, the electronic component was mounted on the said FPC.

  Moreover, in each said structure, the said protective panel main body was made from a glass plate.

  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. (1) Since high-cost metal pin processing is not performed, the touch window can be connected at low cost. (2) Since there are no standing pins that obstruct solder paste printing, BtoB connectors and ICs can be used. It becomes easy to mount a component such as a chip. (3) Since it is not fixed by inserting a pin, a touch window using a glass support plate for the lower electrode panel is possible.

  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 electrical reliability is obtained. Further, deformation and deterioration of the FPC can be prevented.

  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 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. 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 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.

  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. 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 9 a to 9 d are formed in the lower electrode panel 3 corresponding to the electrode ends 6 c, 7 c, 6 d, 7 d in the connection portion 8.

  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.

  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 of 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, the FPC has a cover lay film 10b that is bonded to a film substrate 10f having a circuit 10c as shown in FIG. 6 to protect and insulate the conductor circuit 10c. Only the side end 10a is not covered for connection. As the film substrate 10f and the coverlay film 10b, for example, a flexible insulating film such as polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like 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).

  A cavity 22 that faces the filling hole 10d by the connection side end portion 10a of the bonded FPC 10, the lower surface of the lower electrode panel 3, and the through holes 9a to 9d provided in the lower electrode panel 3. Is forming. 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, and thereby the bonding position of the FPC 10 is shifted. That is, even when the bonding positions between the respective regions surrounded by the insulating adhesive layer 23 and the through holes 9a to 9d are shifted, the reliability of the 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.

  Reference numeral 16 in FIG. 1 denotes an adhesive layer for bonding the upper electrode sheet 2a and the lower electrode panel 3 of the movable sheet 2 around. In the adhesive layer 16, each connection hole for injecting the conductive adhesive 15 needs to be formed corresponding to each electrode end 6 c, 7 c, 6 d, 7 d in the connection portion 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 such as water-based or acrylic printing paste may be used.

  Next, the 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 in a state of being exposed in 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. It can be done. 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.

[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.

  Examples of the moisture curable resin include silicone adhesives, modified silicone adhesives, urethane adhesives, 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.

[Third Embodiment]
Further, as the 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. In addition, even if the volume shrinks during curing, the filling hole 10d of the FPC is not in contact with the solvent volatile conductive adhesive, so the influence of shrinkage on the FPC is small, and the outgas is also filled. Since it comes out of the use 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 [First Embodiment] to [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. Also, since there are no standing pins that obstruct the printing of the solder paste, it becomes easy to mount components such as BtoB connectors and IC chips.

  further. 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 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 opposite to the surface on which the transparent electrode of the PET film 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.

<Example 2>
Except that the moisture-curable conductive adhesive is filled in place of the thermosetting conductive adhesive, and the moisture-curable conductive adhesive is exposed to the filling hole and cured by moisture absorption. The same as in Example 1. 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.

<Example 3>
Instead of the thermosetting conductive adhesive, it is filled with a solvent volatile conductive adhesive, and the solvent volatile conductive adhesive is cured by drying (solvent volatilization) with the filling hole exposed. Except that, it was the same as Example 1. 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-described protective panels with a touch input function of Examples 1 to 3 were all low in cost, had a high degree of freedom in component mounting and material selection, and were further excellent in FPC connection reliability.

  It is to be noted that, by appropriately combining any of 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.

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 usage example of the protection panel with a touch input function. 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.

Explanation of symbols

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
DESCRIPTION OF SYMBOLS 10a Connection side edge part 10b Coverlay film 10c Circuit 10d Filling hole 10e Metal pin fixing hole 10f Film base material 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 (6)

A lower electrode panel having a lower transparent electrode and a lower circuit provided around the lower transparent electrode on the upper surface of the inflexible protective panel body;
An upper transparent electrode provided at a position opposite to the lower transparent electrode on the lower surface of the flexible transparent insulating film, and an upper circuit provided around the upper transparent electrode; and between the lower electrode panel and the electrode An upper electrode sheet bonded at the peripheral edge so as to form a gap,
A decorative sheet that has a decorative layer that conceals the lower circuit and the upper circuit to form a transparent window on at least one surface of a flexible transparent insulating film, and is bonded to the upper surface of the upper electrode sheet; ,
A protective panel with a touch input function comprising: electrically connecting the FPC to the lower circuit and the upper circuit through a through hole provided in the lower electrode panel,
In the FPC, a circuit is provided on one side of the film base material, and a filling hole penetrating both the film base material and the circuit is formed at the connection side end,
An insulating adhesive layer is provided to leave the periphery of the filling hole at the connection-side end portion of the FPC, and is adhered to the lower surface of the lower electrode panel by the insulating adhesive layer.
Next, a conductive adhesive is filled in the cavity facing the filling hole to electrically connect the FPC to the lower circuit and the upper circuit,
Next, after curing with the conductive adhesive exposed in the filling hole,
Finally, the filling hole is sealed with a sealing material,
An FPC connection method for a protection panel with a touch input function. 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 of the 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.

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