JP2016115237A - Touch panel and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel having an antireflection function of a metal color such as copper, capable of improving productivity by reducing the number of processes, and thereby having an excellent cost merit, and a manufacturing method thereof.SOLUTION: A touch panel includes, on one side of a transparent resin base material 1, a plurality of signal detection electrode wires, and on the other side, a drive signal electrode wire. The signal detection electrode wires and the drive signal electrode wire are made of a copper foil. Each of the electrode wires 3 is covered with a resist film 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a capacitive touch panel made of a transparent resin substrate and a method for manufacturing the same.

  In recent years, a display device (touch-type information input image display device) in which a capacitive touch panel, which is one of input devices, is bonded to a display panel such as a liquid crystal panel or an organic EL panel is used as a two-dimensional coordinate input unit. Widely used in the field of personal computers and personal digital assistants.

  In this touch-type information input image display device, a touch surface on which a touch operation is performed with an indicator such as an operator's finger is formed in a flat shape on the surface side of a flat touch panel body on which electrodes are arranged. This is a two-dimensional coordinate input means.

  The main elements that make up a capacitive touch panel are drive signal electrode lines and signal detection electrode lines. Generally, ITO is a transparent conductive material, or copper is an opaque conductive material. It is made of a metal material. As a method for improving the transparency when using an opaque conductive material such as the latter, for example, a wiring method in which copper or a copper alloy is formed in a mesh shape is disclosed (Patent Document 1). In this way, by improving the transparency (transparency) of the touch panel, it is possible to recognize the image of the display unit provided below the touch panel.

  Capacitive touch panels are roughly classified into a surface type and a projection type. The latter touch type information input image display device includes a plurality of electrodes arranged on a grid in the X direction and the Y direction. Multi-touch is possible, and now it is spreading rapidly.

  The capacitive touch panel includes a glass type and a film type. Since the glass type has a higher transmittance of glass compared to a film and the positional accuracy of a wiring pattern formed on the glass is superior to that of a film, the frame portion covering the wiring can be made small.

  On the other hand, since the film type is lightweight, has high productivity, and has flexibility, it can be easily attached to a display panel. Therefore, demand is increasing because it is excellent in productivity and can reduce manufacturing costs.

  In general, the film type uses a laminate of a transparent resin base material and a copper foil. The wiring pattern is formed by patterning the copper foil by a photolithography method. For example, a touch panel can be manufactured by using two laminates, forming a plurality of signal detection electrode lines on one side, forming a plurality of drive signal electrode lines on the other side, and bonding them together. it can.

  In addition, unlike the above method, a plurality of signal detection electrode lines are formed on one surface of the transparent resin substrate using a laminate in which copper foil is bonded to the front and back of the transparent resin substrate, and a plurality of signals are formed on the other surface. The drive signal electrode line can be formed to produce a touch panel.

  In the touch panel described above, there is a problem that it is difficult to see a display image of a liquid crystal display or the like installed under the touch panel due to reflected light generated on the surface of the copper foil forming the electrode wire. As a countermeasure, for example, a method for preventing reflection by forming a blackened layer 5 by blackening a copper foil surface (including side surfaces) forming electrode wires as in Patent Document 2 is disclosed (see FIG. 2). 3).

  In general, as a method for forming fine electrode wires using a laminate in which a copper foil is bonded to a transparent resin substrate, for example, a photolithography method as shown in FIG. 4 is used. In order to prevent reflection at the electrode lines, the blackening layer 5 is formed by blackening so as to cover the electrode lines. Accordingly, although there is an antireflection effect, a complicated process is required, and there is a problem in productivity and cost.

JP 2006-344163 A JP 2013-206315 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a touch panel having an antireflection function and a method for manufacturing the same, which improves productivity by reducing the number of processes, thereby improving cost. To do.

The invention according to claim 1 for achieving the above object is a touch panel in which a plurality of signal detection electrode lines are formed on one surface of a transparent resin substrate and a plurality of drive signal electrode lines are formed on the other surface. Because
The signal detection electrode line and the drive signal electrode line are made of copper foil, and each electrode line is covered with a resist film.

  The invention according to claim 2 is the touch panel according to claim 1, wherein the resist film is formed of a resist composition containing a color pigment.

  According to a third aspect of the present invention, there is provided a step of forming a resist film on both sides of a laminate in which a copper foil is bonded to both sides of a transparent resin base material, and forming a plurality of signal detection electrode lines on one side of the laminate A step of exposing through a photomask for forming, a step of exposing through a photomask for forming a plurality of drive signal electrode lines on the other surface of the laminate, and patterning the resist film by development A step of etching the exposed copper foil to pattern the copper foil, and heating to form a resist film remaining on the patterned copper foil so as to cover each electrode wire It is a manufacturing method of a touch panel which consists of a process.

  The invention according to claim 4 is the touch panel manufacturing method according to claim 3, wherein the resist film is formed of a resist composition containing a color pigment.

  According to the first aspect of the present invention, the signal detection electrode line and the drive signal electrode line made of copper foil are respectively covered with the resist film, thereby reducing reflection of external light on the copper foil surface. As a result, it is possible to improve the difficulty of viewing the image on the display body.

  According to the invention of claim 2, by forming a resist film from a resist composition containing a color pigment, reflection of external light on the copper foil surface can be further reduced, and the image of the display body can be reduced. The difficulty of seeing can be further improved.

According to the invention of claim 3, a step of forming a resist film on both sides of a laminate in which a copper foil is bonded to both sides of a transparent resin substrate, and a plurality of signal detection electrodes on one side of the laminate A step of exposing through a photomask for forming a line, a step of exposing through a photomask for forming a plurality of drive signal electrode lines on the other surface of the laminate, and developing a resist film Patterning the exposed copper foil, patterning the copper foil, and heating the resist film remaining on the patterned copper foil to cover each electrode line By manufacturing a touch panel comprising the steps of forming the touch panel, the process of removing and removing a resist film that is conventionally unnecessary after electrode line formation becomes unnecessary, and the touch panel can be manufactured with fewer steps.

  As described above, according to the present invention, a touch panel having a film-type antireflection function can be manufactured and provided with fewer steps than in the past.

It is a section schematic diagram showing one embodiment of the touch panel of the present invention. It is a cross-sectional schematic diagram which shows one Embodiment of the manufacturing process of FIG. It is a section schematic diagram showing one embodiment of the conventional touch panel. FIG. 4 is a schematic cross-sectional view showing an embodiment of the manufacturing process of FIG. 3.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

  As shown in FIG. 1, the present invention is a touch panel in which a plurality of signal detection electrode lines are formed on one surface of a transparent resin substrate 1, and a plurality of drive signal electrode lines are formed on the other surface, The signal detection electrode line and the drive signal electrode line are made of copper foil 3, and each electrode line is covered with a resist film 4 containing a color pigment, and thereby external light on the copper foil 3 forming the electrode line. It is a touch panel characterized by preventing reflection of light.

  The touch panel of the present invention uses a laminated body in which a copper foil 3 is bonded to the front and back of a transparent resin base material 1 (transparent film and sheet base material) with an adhesive 2 and signals by a known photolithography method. It is obtained by forming a detection electrode line and a drive signal electrode line.

  Hereinafter, the manufacturing method of the touch panel of the present invention will be specifically described with reference to FIG.

  Using the laminate formed by bonding the copper foil 3 to the front and back of the transparent resin substrate 1 shown in FIG. 2 (a) via the adhesive 2, the copper foil 3 on the front and back as shown in FIG. 2 (b). A resist film 4 containing a color pigment is formed thereon.

  Next, although not shown in the drawing, exposure and development are performed through a photomask for forming a signal detection electrode line on one side of the transparent resin substrate 1 and a drive signal electrode line on the other side, and FIG. A pattern of the resist film 4 as shown in (c) is formed to expose the copper foil 3.

  Next, as shown in FIG. 2D, the exposed copper foil 3 is treated with an etching solution, and unnecessary copper foil is removed to form a desired pattern of the copper foil 3. At this time, the resist film 4 on the copper foil 3 can be made wider than the etched copper foil 3, that is, the electrode line, by setting the etching conditions.

  Next, without removing and removing the resist film 4 on the electrode wire, the resist film 4 is sagged by heat treatment in the state shown in FIG. 2D, and the resist film as shown in FIG. 4 can be formed so as to cover each electrode wire (copper foil 3).

  On the other hand, as shown in FIG. 4E, a conventional touch panel manufacturing method using a photolithographic method removes an unnecessary resist film 4 after patterning the copper foil 3, and thereafter, as shown in FIG. 4F. A step of forming a blackened layer 5 by performing blackening treatment as antireflection is necessary.

  As described above, according to the present invention, the process of removing and removing the resist film that is unnecessary after the electrode line formation is unnecessary, and the touch panel can be manufactured with fewer processes.

  In the above method, the signal detection electrode line and the drive signal electrode line can be formed on both sides at the same time, or after forming one electrode line pattern, the other electrode line pattern can be formed. The former is desirable in terms of cost.

  Specifically, the former method is a method in which a photoresist is applied on the front and back metal layers of the transparent resin substrate 1, and mask exposure, development, and etching steps are performed simultaneously. This method requires two exposure light sources, but the development process and the etching process can be performed with the same apparatus, and high productivity can be obtained.

  On the other hand, in the latter method, it is necessary to protect the other surface side during the step of forming the electrode line pattern on one surface side, and already during the step of forming the electrode line pattern on the other surface side. It is necessary to protect the electrode line pattern formed on one side. Therefore, the process and material to protect become a big burden compared with the former.

  As the transparent resin substrate 1 that can be used in the present invention, those having excellent transparency, physical strength, and chemical strength are preferable, and examples thereof include polyester resins, polyolefin resins, and (meth) acrylic resins. Can do. Among these, polyethylene terephthalate (PET) is more preferable. Moreover, as a film thickness of the said transparent resin base material 1, 10-500 micrometers is preferable.

  The laminated body which bonded the copper foil 3 on the front and back of the said transparent resin base material 1 apply | coats the adhesive agent 2 to the transparent resin base material 1, it dries, and is well-known methods, such as the dry laminating method of bonding by a hot pressure Can be produced.

  As a material for forming the electrode wire, any conductive material can be used. However, copper foil is preferable from the viewpoint of excellent electrical characteristics, ease of processing, and cost, and the accuracy and cost of pattern formation by etching are reduced. Considering this, the film thickness is preferably 2 to 15 μm.

  The adhesive used for laminating the transparent resin substrate 1 and the copper foil 3 is not particularly limited. If there are no problems in consideration of adhesive strength, ease of application, cost, etc., a known adhesive is used. Can be used.

  Next, a photoresist (resist composition) for forming the resist film 4 according to the present invention and sagging due to heat treatment of the resist film 4 will be described.

  In the present invention, a resist film 4 containing a color pigment is used, and the resist film 4 remains on the electrode wire after the electrode wire made of the copper foil 3 is formed. The subsequent heat treatment causes the resist film 4 to sag. Thus, the electrode wire is covered to have an antireflection effect.

  The resist composition for forming the resist film 4 includes, but is not limited to, a color pigment, a positive resin or a negative resin, a photoinitiator, a dispersant, a stabilizer, a solvent, and the like. Mold resins are preferred.

  Among these, since the color pigment is a component that acts as an antireflection of external light by the copper foil 3, the hue is not particularly limited as long as the effect is obtained.

  Moreover, it does not specifically limit as positive type resin, A well-known thing can be used. Among them, those that easily overhang and cause a sagging phenomenon by heating after curing are preferable. The heat treatment after curing depends on the heat resistance of the transparent resin substrate 1 to be used. For example, when PET is used as the transparent resin substrate 1, it is desirable to set the heating at 120 ° C. as the upper limit. As a heat treatment method, for example, a method in which the heating temperature is gradually increased to the maximum temperature and then is gradually decreased to room temperature, and a general-purpose heating oven can be used.

  The touch panel of this invention needs to form a transparent protective layer so that the whole electrode line pattern side formed above may be covered. As the transparent protective layer, an acrylic resin, a polyester resin, a polycarbonate resin, or the like excellent in transparency can be used.

  Examples of the acrylic resin include polymers and copolymers of acrylic acid esters and methacrylic acid esters. Among them, polymethyl methacrylate (PMMA) is preferable from the viewpoint of transparency and strength.

  Examples of the polyester-based resin include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate resin, and the like. Among them, transparency, physical, chemical strength, heat resistance, etc. PET is preferred.

  As a method of forming the transparent protective layer, a film or sheet-like base material made of the above resin is laminated on a signal detection electrode line and a drive signal electrode line via a transparent adhesive (OCA). May be. It can also be formed by applying, drying and curing an ionizing radiation curable resin composition comprising the above resin.

  The transparent protective layer is preferably made of the same material as the front and back in order to suppress warpage. However, as a result of intensive studies by the inventors, it has been found that even if different materials are used on the front and back sides, the same warp suppressing effect can be obtained if the difference in thermal expansion coefficient between the two is within 10%.

  The transparent protective layer preferably has a thickness of 0.1 mm to 5 mm. Within this range, physical and chemical strength can be provided without affecting the sensitivity of the sensor. If the film thickness is less than 0.1 mm, the sensitivity of the sensor is not affected, but the physical and chemical strengths are insufficient and there is a problem in long-term durability. On the other hand, when the film thickness exceeds 5 mm, the strength is not a problem, but the influence on the sensitivity of the sensor is a problem.

  The touch panel according to the present invention can be used as various types of input devices such as smartphones, portable information terminals such as tablets, and car navigation systems.

DESCRIPTION OF SYMBOLS 1 ... Transparent resin base material 2 ... Adhesion layer 3 ... Copper foil 4 ... Resist film 5 ... Blackening layer

Claims (4)

A touch panel in which a plurality of signal detection electrode lines are formed on one surface of a transparent resin base material and a drive signal electrode line is formed on the other surface,
The touch panel, wherein the signal detection electrode line and the drive signal electrode line are made of copper foil, and each electrode line is covered with a resist film.   The touch panel according to claim 1, wherein the resist film is formed of a resist composition containing a color pigment.   Through a photomask for forming a plurality of signal detection electrode lines on one side of the laminate, and a step of forming a resist film on both sides of the laminate in which copper foil is bonded to both sides of the transparent resin substrate A step of exposing, a step of exposing via a photomask for forming a plurality of drive signal electrode lines on the other surface of the laminate, a step of developing and patterning a resist film, and an exposed copper foil A method for manufacturing a touch panel, comprising: a step of patterning a copper foil by etching and a step of forming a resist film remaining on the copper foil patterned by heating so as to cover each electrode wire .   The said resist film is formed from the resist composition containing a color pigment, The manufacturing method of the touchscreen of Claim 3 characterized by the above-mentioned.

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