JP4809681B2 - Capacitive touch panel - Google Patents

Description

  The present invention relates to a method for producing a surface conductive molded article, and more particularly to a method for producing a surface conductive molded article using an in-mold transfer molding method and a molded article obtained thereby.

  The in-mold transfer molding method is also called the in-mold painting transfer method, and after inserting the transfer foil formed by printing or vapor-depositing the pattern on the base film into the mold The molten resin is injected and molded. According to this molding method, the molten resin solidifies in the mold to become a molded product, and at the same time, the pattern layer is peeled off from the base film of the transfer foil by the pressure and heat at the time of injection molding and transferred to the surface of the molded product. The

Since this in-mold transfer molding method performs molding and transfer simultaneously, not only is post-processing required to decorate resin molded products, but also the design can be accurately transferred to resin molded products with various three-dimensional curved surface structures. it can. Recently, an apparatus capable of double-in-mold molding and transfer has been put into practical use, and a resin molded product with both sides decorated using this apparatus has also been manufactured.
For this reason, it is widely used for decorating the outer surface of home appliances, automobile interior parts, kitchenware, miscellaneous goods, cosmetics, toys and the like.

  In addition, in order to expose the metallic luster from the surface of the molded product, a transfer foil including a metal layer has been used in the past, but since the vapor deposition film exhibits a good metallic luster, as a metal layer of the transfer foil, A vapor deposition film is used.

Publication No. 2004-261977

By the way, touch panels that can be operated simply by touching with a finger or the like have been widely adopted recently, and various types of detection principles such as a capacitance type and a resistance film type are known. Of these, the capacitance type (more specifically, the analog capacitive coupling type) is mainly used because it detects changes in the capacity of panel members that have changed when touched by a finger and the operation is stable. Has been.
When manufacturing a panel member of this capacitive touch panel, conventionally, a PVD method such as sputtering, vacuum deposition, ion plating, CVD method, foil pasting, etc. under an insulating substrate prepared in advance. To form a conductive layer. Furthermore, since the environmental resistance is low if the conductive layer is exposed, a protective layer for covering the conductive layer is also formed.
Therefore, a plurality of processes are necessary, which is a factor that increases the manufacturing cost.

Therefore, in order to solve the above problems, the present invention significantly reduces the number of processes compared to a manufacturing method in which a conductive layer is formed after preparing a conventional insulating substrate and further a protective layer and the like are formed. It is an object of the present invention to provide a method for forming a surface conductive portion that enables cost reduction.
Moreover, an object of this invention is to provide the manufacturing method suitable as a panel member of an electrostatic capacitance type touch panel, and the panel member obtained by it.

As a result of diligent research to solve the above problems, it was found that a molded product having a surface conductive portion with excellent environmental resistance characteristics can be produced in one step without using a post-process using an in-mold molding transfer method. The invention has been completed.
The invention of claim 1 is a double- in-mold transfer using a transfer foil comprising a base film, a release layer formed on the base film, and a conductive ink layer formed on the release layer. A surface conductive part is formed at least in part by molding, and a desired pattern is formed on the back side of the molded product, manufactured by a method for manufacturing a conductive molded product that produces a surface conductive molded product having excellent environmental resistance. The capacitive touch panel includes a panel member on which a conductive ink layer is formed and a pattern layer is formed on the surface side corresponding to the pattern of the conductive ink layer .

The invention of claim 2 is the capacitive touch panel according to claim 1, a capacitive touch panel design layer is formed of a display layer formed on the back surface side of the half mirror layer.

According to the manufacturing method of the present invention, molding of a molded product and formation of a surface conductive portion excellent in environmental resistance characteristics can be achieved in one step, and the cost can be greatly reduced.
The surface conductive molded product obtained by the method of the present invention is suitable as a panel member for a touch panel, particularly a capacitive touch panel.

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 shows an electrostatic capacitance type touch panel 1, and a panel member 3 manufactured by the method according to the present embodiment is connected to an IC 2 by a conductive wire. The panel member 3 has a conductive portion on the lower side and an insulating portion on the upper side.
2 shows a front surface and a back surface of the panel member 3 of the touch panel 1, respectively. FIG. 3 shows a cross section of the panel member 3.
The panel member 3 is manufactured by a double in-mold transfer molding method.

Below, the structure of the panel member 3 is demonstrated.
Reference numeral 5 denotes a substantially flat plate-shaped resin molded product, and the molded product 5 is made of an insulating resin such as acrylic resin and suitable for in-mold molding. The thickness of the central part of the molded product 5 is 2 mm, and the thickness of the outer diameter part is 1.5 mm.
Transfer layers 7 and 9 are formed by double-in-mold transfer molding using a transfer foil on both the front side and the back side of the molded product 5.

  First, the back side transfer layer 7 will be described. This transfer layer 7 is formed by transferring the back side transfer foil 11 shown in FIG. 4, and from below (ie, exposed surface side) to above (ie, inward). ), A release layer 13 and a protective layer 15 are formed over the entire surface, and conductive ink layers 17 and 18 are formed on the protective layer 15 in a predetermined pattern. A colored insulating ink layer 19 is formed over the entire surface so as to cover the upper surfaces of the conductive ink layers 17 and 18. Reference numeral 21 denotes an adhesive layer, and the transfer layer 7 is bonded to the back surface of the molded product 5 through the adhesive layer 21.

  On the transfer foil 11 for the back surface, the transfer layer 7 composed of the release layer 13, the protective layer 15, the conductive ink layers 17 and 18, the color-added insulating ink layer 19, and the adhesive layer 21 is formed on the base film 23. At the time of double-in-mold transfer molding, the transfer layer 7 is peeled off from the base film 23 and transferred onto the back surface of the molded product 5.

The base film 23 is required to have high strength, good heat resistance, and insulating properties. Therefore, it is made of acrylic or polyester, and the thickness is preferably 35 to 40 μm.
The release layer 13 is required to have a high balance between peelability and post-conductivity described later. Therefore, it is made of a wax agent, and the thickness is preferably 0.2 to 0.5 μm. The release layer 13 can be formed by a coating method or the like commonly used in the transfer foil manufacturing field.
The protective layer 15 adheres well to the conductive ink layers 17 and 18 and the color-added insulating ink layer 19, and further has protective performance for preventing deterioration of the above-mentioned layer from heat during double-in-mold transfer molding and post-conductivity described later. In a high balance. Therefore, it is made of an acrylic resin, and the thickness is preferably 1 to 1.5 μm. The protective layer 15 can be formed by a coating method or the like commonly used in the transfer foil manufacturing field.
In this embodiment, the release layer 13 and the protective layer 15 are made of a transparent material, and the conductive ink layers 17 and 18 and the color-added insulating ink layer 19 are visible from the outside.

The conductive ink layers 17 and 18 are required to have a high balance between conductivity and migration described later. That is, due to the heat and pressure received during the double-in-mold transfer molding method, a part of the conductive component contained in the conductive ink layers 17 and 18 shifts downward when completed, that is, the protective layer 15 that is insulative. It is required to form conductive surfaces 25 and 26 penetrating through the release layer 13 (that is, to conduct afterwards) and to form surface conductive portions 27 and 28 exposed on the lowermost release layer 13.
Therefore, it is made of conductive ink such as silver ink, silver-carbon ink, carbon ink, and the thickness is preferably 3 to 4 μm.

The conductive ink layers 17 and 18 can be formed by a printing method or the like commonly used in the transfer foil manufacturing field in the same manner as a normal color-added insulating ink layer. After printing, it is preferable to leave it at 100 ° C. for about 30 minutes and dry it sufficiently.
The conductive ink layers 17 and 18 do not need to be formed on the entire surface, and are separated in a desired pattern and in an electrically insulated form. In order to prevent the short circuit between the adjacent conductive ink layers 17 and 18 with certainty, it is preferable that the conductive ink layer 17 and the conductive ink layer 18 are separated by at least about 0.3 mm.

The additive color insulating ink layer 19 is made of a colored and insulating ink such as black, and the thickness is preferably 3 to 4 μm.
The colored insulating ink layer 19 can be formed by a printing method or the like commonly used in the transfer foil manufacturing field. After printing, it is preferable to leave it at 100 ° C. for about 30 minutes and dry it sufficiently.
The adhesive layer 21 is made of an adhesive that is insulating and adheres at a predetermined temperature and pressure. Therefore, it consists of polymer adhesives, such as an acryl type, and thickness is preferable 3-4 micrometers. The adhesive layer 21 can be formed by a coating method or the like commonly used in the transfer foil manufacturing field in the same manner as a normal adhesive layer.

  Next, the transfer layer 9 on the front surface side will be described. This transfer layer 9 is formed by transferring the transfer foil 29 for surface shown in FIG. 5, and from the upper side (that is, the exposed surface side) to the lower side (that is, the inner side). On the other hand, a release layer 31 and a protective layer 33 are formed over the entire surface, and two kinds of color-added insulating ink layers 35, 36, and 37 are formed below the protective layer 33 in a predetermined pattern. Reference numeral 39 denotes an adhesive layer, and the transfer layer 9 is bonded to the surface of the molded product 5 through the adhesive layer 39.

  In the transfer foil 29 for the surface, the transfer layer 9 including the release layer 31, the protective layer 33, the color-added insulating ink layers 35, 36, and 37 and the adhesive layer 39 is formed on the base film 41. At the time of double-in-mold transfer molding, the transfer layer 9 is peeled off from the base film 41 and transferred onto the surface of the molded product 5.

The type of each component constituting the base film 41, the release layer 31, the protective layer 33, the color-added insulating ink layers 35, 36, and 37, and the adhesive layer 39, the thickness of each layer, and the formation method are the same as those of the conventional transfer foil. Well, it is not basically limited, but when the finished product is applied to a device that detects a change in capacitance such as a capacitance panel, it is desirable to use all insulating materials. Therefore, it is better to refrain from using conductive ink or using a metal vapor deposition film.
Among the additional color insulating ink layers 35, 36, and 37, the additional color insulating ink layers 35 and 36 are respectively provided to distinguish ON and OFF corresponding to the circular pattern of the conductive layers 17 and 18 formed on the back surface side. It is formed with red and green ink.
The gap is filled with the remaining white color-added insulating ink layer 37.

As described above, each layer has been described. In the figure, the thickness ratio of the transfer layer on the back surface side and the front surface side ignores the actual thickness ratio for the sake of easy understanding. It should be understood that it is drawn.
In-mold molding including double in-mold transfer molding can be performed with a commercially available molding machine, but in order to give sufficient heat and pressure to the conductive ink layers 17 and 18 in the direction penetrating the protective layer 15 and the release layer 13. It is preferable to carry out at a holding pressure of 520 kg / cm ² or more, a maximum injection pressure of 1800 kg / cm ² , and a temperature of 230 ° C. or more.

In the panel member 3 obtained by the double-in-mold molding, a part of the conductive ink of the conductive ink layers 17 and 18 moves downward, that is, penetrates the protective layer 15 and the release layer 13 which are insulating. Conductive paths 25 and 26 are formed, and finally surface conductive portions 27 and 28 exposed on the lowermost peeling layer 13 are formed.
The surface resistivity of the surface conductive portions 27 and 28 varies depending on the type of conductive ink used, but it has been confirmed that 10Ω or more can be secured.

ON and OFF touch areas are demarcated by the colored insulating ink layers 35 and 36 exposed in a circular shape on the surface side. When the finger is touched ON, the surface conductive portion (ON ) The capacitance formed by 27 changes, and when OFF is touched with a finger, the capacitance formed by the surface conductive portion (OFF) 28 located thereunder changes and each touch is detected. . Incidentally, reference numerals 43 and 44 denote drawer portions, which are also formed by the conductive ink layers 17 and 18.
At the same time, it has been confirmed that the environmental resistance characteristics can be secured to the same extent as when a conventional protective film is formed.

The panel member 45 which concerns on the 2nd Embodiment of this invention is demonstrated according to FIGS.
In addition, this panel member 45 is an electrostatic capacitance type similarly to the panel member 3 which concerns on 1st Embodiment, and it abbreviate | omits description by attaching | subjecting the same code | symbol to the same component.
In this embodiment, since four touch portions are formed, four conductive layers that are electrically insulated from each other are formed on the transfer layer on the back surface side of the panel member 45.

As shown in FIGS. 7 and 8, the transfer layer 47 on the surface side of the panel member 45 includes a mark transmission processing layer 49 that defines a light transmission pattern, and a half mirror layer 51.
In this embodiment, the molded product 5 functions as a light guide layer.
The mark permeation processing layer 49 is a color-added insulating ink layer formed of black ink, and the four touch portions 50 are expressed by a mark pattern configured by combining ink missing portions and existing portions. The thickness may be approximately the same as that of the color-added insulating ink layer employed in the first embodiment.
The half mirror layer 51 is composed of a metal vapor deposition film, and the light transmittance is preferably about 5 to 50%. Various metal components such as Al (aluminum) are conventionally used as the metal component forming the half mirror layer, but when Sn (tin) is vapor deposited, the vapor deposited grains are separated from each other. It is preferable because it does not conduct and does not cause trouble in the switch function.

Reference numeral 53 denotes a light source.
As shown in FIG. 6, when the power supply (not shown) is OFF, only the metallic luster exhibited by the metal vapor deposition layer can be visually recognized from the surface side, and the mark 50 on the touch portion cannot be visually recognized.
On the other hand, when the power is turned on, a part of the light from the light source 53 passes through the transparent molded product 5 and enters the black ink layer 49 to be emitted as black light. On the other hand, light that does not pass through the black ink 49 is emitted as it is. Both pass through the half mirror layer 51.
Accordingly, the mark 50 of the touch part is floated on the surface side of the panel member 45.

Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to the above-described embodiment, and even if there is a design change within a range not departing from the gist of the present invention. Included in the invention.
For example, the second embodiment merely shows that there is such a design example of the touch part on the front surface side, and it is not always necessary to provide it in terms of electrical function. To put it extremely, when only the conductive ink layer is formed as the additional color layer, only the color of the conductive ink layer is exposed from the front and back surfaces, but there is no problem in terms of electrical function.
Moreover, it is not always necessary for the resin molded product to use the side on which the surface conductive portion is formed on the back surface. Therefore, the present invention can also be applied to a detection member configured to discharge electric charges from the surface conductive portion toward the ground when touched. In the present invention, since the conductive portion is formed by in-mold transfer molding, the conductive portion does not protrude from the surroundings, and there is no inconvenience that it is easy to peel even if the surface conductive portion is formed on the front side surface. .

Conventionally, since the conductive circuit, resistance pattern, etc. were formed by printing conductive ink or attaching a metal vapor deposition film, the shape of the substrate was limited to a two-dimensional shape. These can also be formed on a three-dimensional base material having various curved surfaces by in-mold transfer molding.
Further, when the additive insulating ink layer of the transfer layer contains an adhesive component, it is not necessary to provide a separate adhesive layer.

By the above-described in-mold transfer molding method, the release layer (component: wax type, thickness: 0.5 μm), protective layer (component: acrylic type, thickness: 1.5 μm), conductive ink layer (component: silver, thickness) The transfer layer of the additive color ink layer (component: insulating black ink, thickness: 4 μm) was transferred and molded into a resin molded product (material: acrylic, plate thickness: 2 mm). The conditions for transfer molding were as follows: holding pressure: 540 kg / cm ² , maximum injection pressure: 1800 kg / cm ² , and temperature: 250 ° C.
Comparative product 1 was produced under the same conditions as described above except that a silver deposited film having the same thickness was used instead of the conductive ink layer.
Comparative Example 2 was manufactured by roll transfer using the same transfer foil on a resin molded product having the same shape and size. The conditions for roll transfer were pressure: 18 kg / cm ² and temperature: 200 ° C.

And when the surface resistivity of the exposed part of the conductive ink layer was measured, the product of the present invention was about 10Ω, whereas the surface resistivity of both the comparative product 1 and the comparative product 2 was 1.0 ×. 10 ⁶ Ω or more.

The environmental resistance characteristics of the product of the present invention were tested and were as follows.

According to the production method of the present invention, the resin can be molded and the surface conductivity can be imparted in one step, and the environmental resistance is also excellent.
Therefore, when manufacturing the panel member of the capacitive touch panel, the cost can be greatly reduced.
Further, not only the panel member but also other molded articles that require other surface conductivity and environmental resistance characteristics can be manufactured using the manufacturing method of the present invention.
In particular, because of the characteristics of in-mold molding, the shape of the molded product is not limited, and the conductive part can be manufactured without protruding from the surroundings. Therefore, the method of the present invention can be used for manufacturing various functional articles. .

It is explanatory drawing of the capacitive touch panel which concerns on the 1st Embodiment of this invention. It is a figure of the surface member and the back surface of the panel member of the touch panel of FIG. It is sectional drawing of the panel member of FIG. It is sectional drawing of the transfer foil transcribe | transferred to the back surface side of the panel member of FIG. It is sectional drawing of the transfer foil transcribe | transferred to the surface side of the panel member of FIG. It is explanatory drawing of how the panel member which concerns on the 2nd Embodiment of this invention looks. It is explanatory drawing of the layer structure of the panel member of FIG. It is sectional drawing of the front side surface of the panel member of FIG.

Explanation of symbols

1 ... Capacitive touch panel 2 ... IC
DESCRIPTION OF SYMBOLS 3 ... Panel member 5 ... Resin molded product 7, 9 ... Transfer layer 11 ... Back surface side transfer foil 13 ... Release layer 15 ... Protective layer 17, 18 ... Conductive ink layer 19 ... Additive insulation ink layer 21 ... Adhesive layer 23 ... Base films 25, 26 ... conductive paths 27, 28 ... surface conductive part 29 ... surface transfer foil 31 ... release layer 33 ... protective layer 35, 36, 37 ... colored insulating ink layer 39 ... adhesive layer 41 ... base film 43 44 ... Drawer 45 ... Panel member 47 ... Transfer layer 49 ... Mark transmission layer 50 ... Mark 51 ... Half mirror layer 53 ... Light source

Claims (2)

At least partly by double- in-mold transfer molding using a transfer foil comprising a base film, a release layer formed on the base film, and a conductive ink layer formed on the release layer A conductive ink layer is formed in a desired pattern on the back side of the molded product. A capacitive touch panel comprising a panel member having a pattern layer formed on the surface side corresponding to the pattern of the conductive ink layer . 2. The capacitive touch panel according to claim 1, wherein the design layer is composed of a half mirror layer and a display layer formed on the back side thereof .

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