TW201706800A - Touch panel and method of its manufacturing - Google Patents

Abstract

A touch panel includes a panel member and a multilayer film (10) joined to a front face of the panel member (11), the multilayer film (10) including a conductive film (1, 2) having a conductive layer (1a, 2a) and a protective film (4). In the multilayer film (10), the respective films are laminated to each other via an adhesive layer (5, 6, 7) formed of a thermosetting type adhesive agent and formed in a three-dimensional shape along the front face.

Description

Touch panel and method of manufacturing same

The present invention relates to a touch panel and a method of fabricating the same.

In the past, a touch panel has been used as an input device for an audio device, a home appliance, an electronic device, or the like of a car. The touch panel is usually formed by printing and laminating a conductive layer that changes capacitance on the surface of the insulating film and a decorative layer for decoration. By using the touch panel, there is an advantage that the operation surface can be made flat and various switching members for input operations and the like can be omitted.

The selection of the touch panel is matched with the use or preference of the touch panel, and the like. However, in a film printed and laminated with a decorative layer and a conductive layer, it is not easy to achieve various combinations of the conductive layer and the decorative layer. Therefore, there is a touch panel in which a decorative film having a decorative layer and a conductive film having a conductive layer are bonded by an adhesive (for example, Patent Document 1). Various combinations of the conductive layer and the decorative layer can be easily realized by separately providing the decorative film and the conductive film.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-2450

It is preferable that the touch panel has a three-dimensional shape such as a curved surface in consideration of design or visual considerations in the installation. In the touch panel of Patent Document 1, the decorative film is bonded to the conductive film via an adhesive layer formed of an adhesive by a film embedding method, a Three Dimension Overlay Method, or the like. When the touch panel is formed into a three-dimensional shape by a film embedding method or the like, both films are twisted and deformed by being bonded by the adhesive layer. Therefore, the hardened adhesive layer may break when deformed. In order to prevent the adhesive layer from rupturing, if an adhesive tape is used instead of the adhesive layer, various film materials can be easily attached. However, since the adhesive force of the adhesive tape is usually smaller than that of the adhesive, for example, the film is peeled off from the adhesive tape at a three-dimensionally formed portion having a large undulation. Therefore, in the touch panel, the degree of freedom of the laminated film shape is limited.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a touch panel and a method of manufacturing the same that can be stably maintained even if a laminated film is formed into a three-dimensional shape.

The touch panel of the present invention is characterized in that: a surface plate; and a multi-layer film bonded to the surface of the surface plate and including The conductive film having a conductive layer and the protective film are formed by laminating the respective films through an adhesive layer formed using a thermosetting adhesive, and are formed in a three-dimensional shape along the surface.

In the present configuration, the multi-layer film includes a conductive film and a protective film, and each film is laminated via an adhesive layer made of a thermosetting adhesive. Therefore, the adhesive layer is not cured at normal temperature before heating. Therefore, the multi-layer film can be deformed without breaking the adhesive layer, and the adhesive layer can be hardened during or after forming into a three-dimensional shape while heating the multi-layer film. Therefore, the multilayer film including the conductive film and the protective film can be formed into a three-dimensional shape in a state in which the respective films are in close contact via the adhesive layer. Thereby, when the multi-layer film is formed into a three-dimensional shape, formation distortion is less likely to occur, and internal stress which causes peeling of each film and the adhesion layer is lowered. As a result, in the touch panel, the three-dimensional shape of the multi-layer film can be stably maintained.

Another feature of the touch panel of the present invention is that the protective film is a decorative film having a decorative layer.

As shown in the present invention, in the multi-layer film, if the protective film is a decorative film having a decorative layer, various combinations of the conductive layer and the decorative layer can be easily realized in the touch panel by selecting the decorative film.

A method for manufacturing a touch panel of the present invention has a film manufacturing step of laminating a conductive film having a conductive layer and a protective film via an adhesive layer formed of a thermosetting adhesive to form a multilayer layer. a film forming step of heating and deforming the multi-layer film into a three-dimensional shape; and a panel integration step of disposing the formed multi-layer film in a mold for injection molding and then ejecting in the mold The resin is melted to form a face sheet, and the above-mentioned multi-layer film is integrated with the above-mentioned face sheet.

According to the present feature, the touch panel is manufactured by disposing the multi-layer film in a mold after the formation of the multi-layer film by the film forming step and subjecting it to injection molding. Here, the multi-layer film is produced by a film manufacturing step of laminating a conductive film having a conductive layer and a protective film via an adhesive layer formed of a thermosetting adhesive. At the end of the film manufacturing step, although the adhesive layer of the composite film is not cured, the conductive film and the protective film can be bonded by the adhesiveness. Further, when the temperature of the multi-layer film exceeds the curing temperature of the thermosetting adhesive during or after the film forming step is heated to cause the three-dimensional shape, the adhesive layer is hardened. As a result, in the multi-layer film, since the adhesive layer is hardened in the film forming step, distortion of each film can be suppressed at the time of molding. Thereby, a touch panel in which a stable three-dimensional shape multi-layer film and a face sheet are integrated can be manufactured. Further, even in the case where the hardening of the adhesive layer due to the heating in the film forming step is not completed, the adhesive layer can be cured by heating the multi-layer film in the panel integration step.

1, 2‧‧‧ conductive film

1a‧‧‧1st conductive layer

1b‧‧‧Binder

2a‧‧‧2nd conductive layer

3‧‧‧Plus film

3a‧‧‧plus layer

4‧‧‧Protective film

4a‧‧‧Protective layer

5, 6, 7‧‧‧ adhesive layer

10‧‧‧Multilayer film

11‧‧‧Face plate

12‧‧‧ openings

13‧‧‧End

14‧‧‧section

15‧‧‧Translucent area

20~22‧‧‧Touch panel

30‧‧‧Mold

31, 32‧‧‧ Forming Die

33‧‧‧ convex

34‧‧‧ chamber

35‧‧‧ gate

Fig. 1 is a view showing the structure of a multilayer film.

Fig. 2 is a perspective view of the touch panel of the first embodiment.

Fig. 3 is a cross-sectional view of the arrow III-III in Fig. 2.

Fig. 4 is a view showing a multi-layer film after preliminary forming.

Fig. 5 is a view showing a forming step of the touch film.

Fig. 6 is a view showing a forming step of the touch film.

Fig. 7 is a view showing a forming step of the touch film.

Fig. 8 is a view showing another form of a forming step of the touch film.

Fig. 9 is a view showing another form of a forming step of the touch film.

Fig. 10 is a perspective view of the touch panel of the second embodiment.

Figure 11 is a cross-sectional view of the arrow XI-XI of Figure 10.

Fig. 12 is a perspective view of a touch panel of another embodiment.

The embodiments of the present invention will be described below based on the drawings.

(first embodiment)

The touch panel 20 is configured such that the multi-layer film 10 is laminated on the surface of the face sheet 11 as shown in FIGS. 1 to 3 . The top sheet 11 and the multi-layer film 10 are formed together in a three-dimensional shape. In the present embodiment, the surface of the touch panel 20 is formed in a three-dimensional curved shape. An opening 12 that serves as an operation screen of the touch panel 20 is formed in the center of the face sheet 11.

As shown in Fig. 1, the multi-layer film 10 sequentially laminates the electroconductive thin films 1 and 2 having the conductive layers 1a and 2a, the adhesive layer 6, and the decorative film 3 having the decorative layer 3a. The surface side (upper side of the first drawing) of the decorative film 3 is further laminated with the protective film 4 having the protective layer 4a via the adhesive layer 7.

The first conductive film 1 and the second conductive film 2 are on the base film The first conductive layer 1a and the second conductive layer 2a are provided on the front side. The first conductive film 1 and the second conductive film 2 are laminated via the adhesive layer 5 . Since the first conductive layer 1a detects, for example, a coordinate position in a predetermined direction, and the second conductive layer 2a detects a coordinate position in a direction intersecting the one direction, the combination of the first conductive film 1 and the second conductive film 2 has As a function of the touch sensor. In this embodiment, although the touch sensor is composed of two conductive films 1 and 2, the touch sensor may be composed of one conductive film.

The decorative film 3 has a decorative layer 3a on the back side of the base film. The decorative layer 3a is formed by screen printing, transfer, or the like. The decorative layer 3a is non-transparent and is applied, for example, to the design or color tone of the touch panel 20.

The protective film 4 has a protective layer 4a on the surface side of the base film. The protective layer 4a is coated with a hard material, for example, and has functions such as scratch resistance, low reflection, anti-glare, anti-fingerprint, flaw repair, refractive index adjustment, and hysteresis adjustment.

The protective film 4 can be composed only of the base film which does not have the protective layer 4a below.

The base film of each of the films 1 to 4 is not particularly limited, and for example, polyethylene terephthalate (PET), polycarbonate (PC), acrylate (PMMA), cycloolefin polymer (COP), poly Propylene (PP), polyethylene naphthalate (PEN), cellulose triacetate (TAC), polyamine (PI), and the like. The base film of each of the films 1 to 4 may be all of the same material or different materials.

The adhesive layers 5 to 7 are all formed of a thermosetting adhesive. It is preferred that the thermosetting adhesive has adhesiveness at normal temperature. The type of the thermosetting adhesive is not particularly limited, but for example, an optically clear optical transparent adhesive (OCA) is preferably used.

The thermosetting adhesive can have a certain degree of viscoelasticity after hardening. There may be a difference in subtle formability between the adjacent films of the respective films 1 to 4, or a difference in physical properties such as heat shrinkability and linear expansion coefficient. In this case, if the thermosetting adhesive is viscoelastic, the adhesive layers 5 to 7 serve as a buffer, and the difference in formability or physical properties of each of the films 1 to 4 can be absorbed. Thereby, peeling of each film 1~4 can be prevented.

The thermosetting adhesive may be rigid after hardening. At this time, the interaction of the distortion occurring in each of the films 1 to 4 is broken by the rigidity of the adhesive layers 5 to 7, and the peeling of the respective films 1 to 4 can be prevented.

The multilayer film 10 is formed by applying the adhesive layers 5 to 7 on the surface sides of the first conductive film 1, the second conductive film 2, and the decorative film 3, and laminating the films 1 to 4. Further, on the back side of the electroconductive thin film 1, an adhesive 1b suitable for bonding to the top sheet 11 is applied.

(Manufacturing method of touch panel)

Next, a method of manufacturing the touch film 20 using the film embedding method will be described. The manufacturing method of the touch film 20 has a film manufacturing step for manufacturing a multi-layer film 10, and a film forming step of heating and deforming the multi-layer film 10 into a three-dimensional shape as shown in FIGS. 4 to 7; And a panel integration step of disposing the formed multi-layer film 10 in an injection process The mold 30 is formed, and then molten resin is injected into the mold 30 to form the face sheet 11, and the formed multi-layer film 10 is integrated with the above-mentioned sheet material 11.

In the film manufacturing step (not shown), the conductive film 1 having the conductive layers 1a and 2a, the decorative film 3 having the decorative layer 3a, and the protective film 4 having the protective layer 4a are passed through a thermosetting adhesive. The formed adhesive layer 5~7 is laminated. At the completion of the film manufacturing step, although the adhesive layers 5 to 7 are not hardened, the films 1 to 4 can be joined by the adhesiveness. In the multi-layer film 10 shown in Fig. 2, at least the decorative layer 3a is not formed in the light-transmitting region 15 which is overlapped with the opening 12 of the facing sheet 11. Instead of the pattern of Fig. 2, a decorative layer 3a may be formed on a part of the light-transmitting region 15 of the multilayer film 10.

In the film forming step, as shown in Fig. 4, the multi-layer film 10 is heated and preliminary formed into a three-dimensional shape. The preliminary forming of the multilayer film 10 is performed by hot pressing, vacuum forming, pressure forming, or the like. When the temperature of the multilayer film 10 exceeds the curing temperature of the thermosetting adhesive of the adhesive layers 5 to 7 by heating in the film forming step, the adhesive layers 5 to 7 are hardened.

Next, as shown in FIG. 5, the pre-formed multi-layer film 10 is placed along the inner surface of the molding die 31 which is one of the injection molding molds 30. As shown in Fig. 6, when the mold 30 is closed, the convex portion 33 of the other molding die 32 abuts against the multi-layer film 10, and the chamber 34 is formed around the convex portion 33.

Thereafter, as shown in FIG. 7, the chamber 34 is gated 35. The molten resin is injected to form the sheet material 11, and the multi-layered film 10 having the three-dimensional shape is integrated with the sheet material 11. The touch panel 20 is manufactured by this integration step.

As a result, in the film forming step, the multi-layer film 10 is cured by heating to bond the adhesive layers 5 to 7. Therefore, the multi-layer film 10 can be formed into a three-dimensional shape in a state in which the respective films 1 to 4 are in close contact via the adhesive layers 5 to 7. As a result, the multilayer film 10 is less likely to be deformed when formed into a three-dimensional shape, and the internal stress which causes the peeling of the respective films 1 to 4 and the adhesive layers 5 to 7 is lowered. As a result, the touch panel 20 in which the stable three-dimensionally shaped multi-layer film 10 and the face sheet 11 are integrated can be manufactured. Further, even in the case where the hardening of the adhesive layers 5 to 7 due to the heating of the film forming step is not completed, the adhesive layer 5 to 7 can be hardened by heating the multi-layer film 10 in the panel integration step. carry out.

When the multi-layer film 10 is preliminary formed in the film forming step, the multi-layer film 10 is usually heated at 60 ° C to 100 ° C. Therefore, if the hardening start temperature of the thermosetting adhesive is different, a corresponding different effect is produced.

The thermosetting adhesive for the adhesive layers 5 to 7 can be used, for example, at 60 ° C or higher. At this time, in the film forming step, the adhesive layers 5 to 7 are not cured, but the adhesive layers 5 to 7 start to harden by heating during preliminary forming in the film forming step.

The thermosetting adhesive may be one that starts to harden at 100 ° C or higher. At this time, the adhesion layers 5 to 7 are hardened by setting the heating temperature of the multilayer film 10 in the film forming step to a higher region. So in thin Before the film forming step, for example, for the multi-layer film 10, the adhesive layer 5 to 7 may be hardened during the autoclave treatment or the annealing treatment, but the adhesive layer 5 may be started at the film forming step. ~7 hardened. Further, by lowering the heating temperature of the film forming step, it is possible to suppress the adhesion of the adhesive layers 5 to 7 of the multi-layer film 10 in the film forming step, and to cure the adhesive layers 5 to 7 in the panel integration step.

The thermosetting adhesive may be one that starts to harden at 250 ° C or higher. At this time, the hardening start temperature of the thermosetting adhesive is higher than the heating temperature at the time of preliminary forming of the film forming step. Therefore, when the multilayer film 10 is placed on the mold 30, the adhesive layers 5 to 7 are not yet cured. Therefore, in the panel integration step, even if the pre-formed multi-layer film 10 is placed in the mold 30 in the state in which the slit is present, the multi-layer film 10 can be corrected to the shape of the mold 30 by the injection pressure of the molten resin. Further, in this state, the adhesive layer 5 to 7 is cured by heating the laminated film 10 by the molten resin.

[Other manufacturing methods of touch panel]

As shown in Figs. 8 to 9, the flat film 10 of the flat plate can be inserted into the mold 30, and the multilayer film 10 can be formed inside the mold 30. The multilayer film 10 is heated, for example, by a heat source (not shown), and is deformed along the molding die 31. Thereafter, the mold 30 is closed, and the molten resin is injected from the shutter 35 to the chamber 34 to form the face sheet 11. Thereby, the touch panel 20 in which the face sheet 11 is integrated can be manufactured in the multi-layered film 10 having a three-dimensional shape.

The multi-layer film 10 inserted into the mold 30 can be closed by The pressing force at the time of the mold 30 is deformed so that at least a part of the shape along the mold 30 is subjected to injection molding by molten resin. As a result, the multi-layer film 10 is deformed by the pressure of the molten resin, and the adhesive layers 5 to 7 are hardened by heating of the molten resin.

[Second embodiment]

In the second embodiment, as shown in FIGS. 10 to 11 , the touch panel 21 is configured such that the multi-layer film 10 is laminated on the entire surface of the surface plate 11 having no opening. Both the face sheet 11 and the multi-layer film 10 are formed in a three-dimensional shape. The top sheet 11 is made of a transparent resin such as polycarbonate, and is configured to have substantially the same shape as the multi-layer film 10. In the multi-layer film 10 shown in Fig. 10, the decorative layer 3a is not formed in the light-transmitting region 15 which becomes an operation screen. Instead of the pattern of Fig. 10, a decorative layer 3a may be formed in a part of the light transmissive region 15 in the multi-layer film 10. The touch panel 21 is manufactured by the same manufacturing method as that of the first embodiment.

In this way, by laminating the multi-layer film 10 and the face sheet 11 in the same shape, the touch panel 21 can be ensured to have a stable strength that satisfies the specifications as a whole. Thereby, the durability of the touch panel 21 is improved. Further, although not shown, a multi-layer film 10 having no decorative layer 3a can be used for the touch panel 21. In this case, the entire surface of the multi-layer film 10 can be used as an operation screen of the touch panel 21.

[Other implementations]

(1) Fig. 12 shows a touch panel 22 of another embodiment. in The surface of the touch panel 22 is formed into a three-dimensional curved shape, and the left and right end portions 13 are folded into a substantially right angle. Further, a partition portion 14 that can be pressed is provided on the surface side of the touch panel 22. The partition portion 14 can be provided in the touch panel 20 of the first embodiment or the touch panel 21 of the second embodiment.

(2) In each of the above embodiments, the multilayer film 10 is provided with the conductive film 1, 2, the decorative film 3, and the protective film 4. However, the multi-layer film 10 not including the protective film 4 may be used. At this time, since the outermost layer of the multi-layer film 10 is the decorative film 3, the decorative film 3 also serves as a protective film. That is, the protective film of the multi-layer film 10 is composed of the decorative film 3. Further, the multi-layer film 10 may be composed of the conductive films 1 and 2 and the protective film 4 without the decorative film 3 .

(3) In the multi-layer film 10, between the electroconductive films 1 and 2, the dummy film may be laminated in order to adjust the sensitivity of the touch panel 20. The dummy film is composed of a base film monomer of each of the films 1 to 4. That is, the dummy film is a film which does not have the conductive layers 1a, 2a, the decorative layer 3a, the protective layer 4a, and the like. Further, between the conductive films 1, 2 and the protective film 4, only the dummy film can be laminated, and the dummy film and the decorative film 3 can be laminated. The thickness of the multi-layer film 10 can be easily adjusted by using a dummy film. Each of the films (the conductive film 1, the decorative film 3, the protective film 4, and the dummy film) is laminated via an adhesive layer formed using a thermosetting adhesive.

(4) The protective film 4, the decorative film 3, and the dummy film provided in the multi-layer film 10 may each be plural. A plurality of films of the same type may be laminated via an adhesive layer formed using a thermosetting adhesive.

(5) In each of the above embodiments, the touch panel is shown The surface of 20 to 22 is set as a three-dimensional curved shape, but the surface of the touch panel may be a three-dimensional shape or a shape other than a curved surface.

(6) In each of the above embodiments, the conductive layers 1a and 2a are formed on the surface side of the conductive films 1 and 2, and the decorative layer 3a is formed on the back side of the decorative film 3. However, the conductive layers 1a, 2a may be formed on the back side of the conductive films 1, 2. Further, the decorative layer 3a may be formed on the surface side of the decorative film 3.

(7) In each of the above embodiments, an example in which the multi-layer film 10 and the top sheet 11 are integrated by a film insertion method is used, but a TOM method may be used instead of the film insertion method.

[Industrial Availability]

The present invention can be widely applied to touch panels installed in automobiles, home electric appliances, electronic appliances, and the like.

1, 2‧‧‧ conductive film

1a‧‧‧1st conductive layer

1b‧‧‧Binder

2a‧‧‧2nd conductive layer

3‧‧‧Plus film

3a‧‧‧plus layer

4‧‧‧Protective film

4a‧‧‧Protective layer

5, 6, 7‧‧‧ adhesive layer

10‧‧‧Multilayer film

Claims (3)

A touch panel comprising: a face plate; and a multi-layer film bonded to a surface of the face plate and comprising a conductive film having a conductive layer and a protective film, wherein the film is made to be thermally hardened by using each film The adhesive layer formed by the adhesive is laminated and formed in a three-dimensional shape along the aforementioned surface. The touch panel according to the first aspect of the invention, wherein the protective film is a decorative film having a decorative layer. A method for manufacturing a touch panel, comprising: a film manufacturing step of laminating a conductive film having a conductive layer and a protective film through an adhesive layer formed by using a thermosetting adhesive; a forming step of heating and deforming the multi-layer film into a three-dimensional shape; and a panel integration step of disposing the formed multi-layer film in a mold for injection molding, and then ejecting the molten resin in the mold The face sheet is formed, and the above-mentioned multi-layer film is integrated with the above-mentioned face sheet.