JP6665992B2 - Manufacturing method of capacitive touch panel - Google Patents

Description

  The present invention relates to a method for manufacturing a capacitive touch panel.

  A capacitive touch panel that is disposed so as to overlap with a display area of a display device has, on its substrate, an x-direction electrode extending in the x direction and juxtaposed in the y direction and a y-direction extending in the x direction. The juxtaposed y-direction electrodes are formed insulated.

  In the capacitive touch panel thus configured, when a finger or the like touches the touch panel, a capacitance change occurs in the electrode at that location, and the x-direction electrode, y in which the capacitance change occurs by an external control circuit (controller). The x and y coordinates are calculated by detecting the direction electrodes, and the information is reflected on the display device.

  In addition, the capacitive touch panel has a substrate, an x-direction electrode, a y-direction electrode, and the like formed of a light-transmitting material, so that a display area of a display device can be visually observed through the capacitive touch panel. It is associated with the x and y coordinates in the display area of the device.

  Such a technique is disclosed, for example, in Patent Document 1 below.

US Patent US005844506A

  However, in the above-mentioned capacitive touch panel, the substrate is a glass substrate, and each of the x-direction electrode and the y-direction electrode is formed of a transparent conductive film (eg, ITO: Indium Tin Oxide) formed by sputtering using a photolithography technique. It is patterned by selective etching. For this reason, it is unavoidable to adopt a vacuum process for forming the transparent conductive film on the substrate, which complicates the operation and increases the manufacturing cost.

  Further, since sputtering is used for forming the transparent conductive film on the substrate, for example, the process temperature is relatively high, and a heat-resistant glass substrate must be used as the substrate, and the impact resistance is high. This has made it difficult to realize a bendable capacitive touch panel.

  Further, a transparent conductive film such as ITO is made of a metal oxide, and the light refractive index of the metal oxide is relatively different from the light refractive index of the insulating film interposed between the x-direction electrode and the y-direction electrode. I cannot escape. For this reason, there is a disadvantage that the respective patterns of the x-direction electrode and the y-direction electrode are easily viewed.

  An object of the present invention is to provide a method of manufacturing a capacitive touch panel having a configuration that can be easily manufactured.

  It is another object of the present invention to provide a method of manufacturing a capacitive touch panel that has high impact resistance and can be bent.

  Another object of the present invention is to provide a method of manufacturing a capacitive touch panel in which the pattern of the electrodes is hard to see.

  In the capacitive touch panel according to the present invention, the x-direction electrode and the y-direction electrode are made of a transparent polymer material formed by coating.

  The configuration of the present invention can be, for example, as follows.

(1) The method for manufacturing a capacitive touch panel according to the present invention includes:
An insulating substrate made of resin,
A plurality of first electrodes made of a transparent conductive film formed on the insulating substrate;
An insulating film formed on the plurality of first electrodes;
A plurality of second electrodes, which are formed on the insulating film, are made of a transparent conductive film, and intersect with the first electrodes;
In a method of manufacturing a capacitive touch panel including a protective film formed on the plurality of second electrodes,
A step of applying a photosensitive polymer material to the insulating substrate in the air and patterning by photolithography to form the first electrode;
A step of applying a liquid photosensitive polymer material on the insulating substrate including the first electrode in the air, patterning the liquid photosensitive polymer material by photolithography, and forming the insulating film;
A step of applying a photosensitive polymer material on the insulating film in the air and patterning by photolithography to form the second electrode;
Covering the second electrode in the air, applying an organic resin material, and forming the protective film.

  (2) The method for manufacturing a capacitive touch panel according to the present invention is characterized in that in (1), the protective film and the first electrode and the second electrode have substantially the same refractive index. I do.

  (3) In the method for manufacturing a capacitive touch panel according to the present invention, in (1), the protective film can be applied by screen printing or an inkjet method.

  The configuration described above is merely an example, and the present invention can be appropriately changed without departing from the technical idea. Examples of the configuration of the present invention other than the above-described configuration will be apparent from the entire description of the present specification or the drawings.

  According to the method of manufacturing the capacitive touch panel configured as described above, it is possible to provide a configuration that can be easily manufactured. In addition, it is possible to make the impact resistance strong and bendable. Further, the electrode pattern can be configured so as to be hard to visually confirm.

  Other effects of the present invention will be apparent from the description of the entire specification.

FIG. 2 is a cross-sectional view illustrating an embodiment of the capacitive touch panel of the present invention, and corresponds to a cross section taken along line II of FIG. 2. 1 is a plan view of an embodiment of the capacitive touch panel of the present invention. FIG. 3 is a structural diagram showing an example of a material used for an electrode of the capacitive touch panel of the present invention. FIG. 2 is a circuit diagram showing an embodiment of a touch panel controller connected to the capacitive touch panel of the present invention. FIG. 5 is a diagram illustrating timings of signals of the touch panel controller illustrated in FIG. 4. 1 is an exploded perspective view showing an embodiment of a screen input type display device of the present invention. It is a block diagram showing the state where the screen input type display device of the present invention was connected to the mobile device. FIG. 6 is a cross-sectional view illustrating another embodiment of the capacitive touch panel of the present invention. FIG. 10 is an exploded perspective view showing another embodiment of the screen input type display device of the present invention. It is an explanatory view showing an example of a device to which a screen input type display device of the present invention is applied.

  Embodiments of the present invention will be described with reference to the drawings. In each drawing and each embodiment, the same or similar components are denoted by the same reference numerals, and description thereof will be omitted.

<Example 1>
(Capacitive touch panel)
FIG. 2 is a plan view showing Example 1 of the capacitive touch panel (hereinafter, may be simply referred to as a touch panel) of the present invention. FIG. 1 is a cross-sectional view taken along line II of FIG.

  In FIG. 2, there is, for example, a rectangular substrate SUB. The substrate SUB is arranged, for example, so as to overlap the liquid crystal display panel, and is formed corresponding to the size of the liquid crystal display panel. This substrate SUB is made of, for example, glass or resin.

  For example, a plurality of y-direction electrodes YP are formed on the surface of the substrate SUB. The y-direction electrodes YP are formed so as to extend in the y-direction in the figure and be juxtaposed in the x-direction. The y-direction electrode YP is formed in a pattern in which portions having a small line width and portions having a large line width are alternately arranged in the extending direction. In the y-direction electrode YP, a portion having a small line width has a short line length, and a portion having a large line width has a large line length. A portion where the line width of the y-direction electrode YP is large (this portion may be referred to as a pad portion PDy) has, for example, a rhombic shape, and is connected to a portion having a small line width at a pair of diagonal portions. ing. Each pad portion PDy of the y-direction electrode YP is arranged in the x direction in the drawing together with the pad portions PDy of the other y-direction electrodes YP arranged in parallel. Here, the y-direction electrode YP is formed of a transparent conductive film, and the material is formed of a polymer material formed by coating. The above-mentioned pattern can be formed by applying the polymer material to the surface of the substrate SUB and performing selective etching by photolithography. In this case, by using a photosensitive material as the polymer material, it is possible to form the above-described pattern only by photolithography technology (omission of selective etching). As the polymer material, for example, polypyrrole, polyaniline, polyacetylene, polythiophene, polyphenylenevinylene, polyferylene sulfide, polyp-phenylene, and polyheterocyclic vinylene can be used. As a typical polymer material, for example, a substituted polythiophene called PEDOT having a structural formula shown in FIG. 3 and poly (3,4-ethylenedioxythiophene) can be used. The polymer material having photosensitivity can be formed by adding a photopolymerization initiator and a binder: a polyfunctional acrylic monomer to the polymer material described above. Then, by adding an insulating material formed by coating to the above-described polymer material, a transparent conductive film can be formed in a predetermined pattern using, for example, screen printing or inkjet. That is, a transparent conductive film having a predetermined pattern can be formed without using a photolithography technique. In the y-direction electrode YP thus configured, the sheet resistance is less than 1000 (Ω / □), the light transmittance is 90% or more at a thickness of 400 to 700 nm, and the light refractive index is less than 2.0. It is confirmed that.

  Each of the y-direction electrodes YP is led out from, for example, a lower end in the drawing as a wiring WLy having a small line width, and is connected to a connector CN mounted on, for example, the lower right of the substrate SUB.

  An insulating film IN is formed on the surface of the substrate SUB so as to cover the y-direction electrode YP. The insulating film IN functions as an interlayer insulating film in which an x-direction electrode XP described later formed on the upper surface is insulated from the y-direction electrode YP. Here, the insulating film IN is formed of a SiO-based material formed by coating or an organic resin-based material formed by coating. As the SiO-based material formed by coating, SOG (Spin on Glass: a liquid in which silica (SiO2) is dissolved in a solvent) can be used. These materials are usually liquid and can be formed by coating on the surface of the substrate SUB. By adding photosensitivity to the insulating film IN, pattern processing can be performed only by a photolithography technique, and an etching step can be omitted. In addition, by using an organic resin-based material formed by coating as the insulating film IN, the insulating film IN can be formed in a predetermined pattern using, for example, screen printing or inkjet. That is, the insulating film IN having a predetermined pattern can be formed without using a photolithography technique. In the insulating film IN thus configured, the heat resistance is desirably higher than 150 ° C., the dielectric constant is desirably 3 to 4 at 1 MHz, the pattern resolution is desirably about 5 μm or less, and the visible light transmittance is 90. %. Further, the optical refractive index is desirably 1.2 to 2.0.

  On the surface of the insulating film IN, for example, a plurality of x-direction electrodes XP are formed. The x-direction electrodes XP are formed so as to extend in the x-direction in the figure and be juxtaposed in the y-direction. The x-direction electrode XP is formed in the same pattern as the y-direction electrode YP. That is, in the extending direction of the x-direction electrode XP, the pattern is formed in a pattern in which portions having a small line width and portions having a large line width are alternately arranged. In the x-direction electrode XP, a portion having a small line width has a short line length, and a portion having a large line width has a large line length. A portion of the x-direction electrode XP where the line width is large (this portion may be referred to as a pad portion PDx) has a rhombic shape, and is connected to a portion where the line width is small at a pair of diagonal portions. I have. Each pad portion PDx of the x-direction electrode YP is arranged side by side in the y direction in the drawing together with the pad portions PDx of the other x-direction electrodes XP arranged side by side. Then, when viewed in a plan view, each pad portion PDx of the x-direction electrode XP is arranged in a region surrounded by four adjacent pad portions PDy of the y-direction electrode YP without overlapping with each other. Has become. This relationship is the same in each pad portion PDy of the y-direction electrode YP, and these pad portions PDy are arranged in a region surrounded by four adjacent pad portions PDx of the x-direction electrode XP without overlapping with each other. It has become so. The y-direction electrode YP and the x-direction electrode X are designed to overlap each other at intersections where the line width is small.

  Here, the x-direction electrode XP is made of a transparent conductive film, and is made of a polymer material formed by coating, like the y-direction electrode YP. In this case, the material of the x-direction electrode XP does not need to be exactly the same as the material of the y-direction electrode YP, but is selected from the above-described materials of the y-direction electrode YP.

  Each of the x-direction electrodes XP is drawn out from, for example, a right end in the drawing by a wiring WLx having a small line width, and is connected to the connector CN.

  On the surface of the substrate SUB, a protective film PS is formed so as to cover the x-direction electrode XP. The protective film PS is provided to protect the x-direction electrode XP from external injury and the like. Here, the protective film PS is formed of a SiO-based material formed by coating or an organic resin-based material formed by coating similarly to the insulating film IN. It is formed by similar manufacturing. In this case, the material of the protective film PS does not need to be exactly the same as the material of the insulating film IN, but is selected from the above-described materials of the insulating film IN and the like.

  The capacitive touch panel thus configured can form the y-direction electrode YP, the insulating film IN, the x-direction electrode XP, and the protective film PS on the surface of the substrate SUB using a material applied in the air. . This means that the work can be made extremely easy as compared with a conventional method in which the y-direction electrode YP and the x-direction electrode XP are formed by ITO (Indium Tin Oxide) or the like formed by vapor deposition or the like in a vacuum atmosphere. The cost can be significantly reduced. In this case, the material layer can be processed (patterned) without using selective etching only by the photolithography technique. In such a case, the work can be further facilitated and the manufacturing cost can be significantly reduced. . Further, the material layer can be formed by, for example, printing or the like, and in this case, since the patterning can be performed without using the photolithography technology, the operation can be further facilitated and the manufacturing cost can be significantly reduced. .

  The capacitive touch panel thus configured can suppress the process temperature to a low temperature of 200 ° C. or less in forming the y-direction electrode YP, the insulating film IN, the x-direction electrode XP, and the protective film PS. Therefore, as the substrate SUB, a resin film, a metal thin film having a surface subjected to insulation treatment, or the like can be used. Therefore, it is possible to obtain a touch panel which has high impact resistance or can be used by being bent.

  The capacitive touch panel thus configured is made of a polymer material formed by coating the y-direction electrode YP and the x-direction electrode XP, and the polymer material formed by coating is an optical material. The characteristics can be controlled, for example, the refractive index can be made substantially equal to the refractive index of the insulating film IN or the protective film PS. Therefore, when viewed in a plan view, it is possible to obtain an effect of making it difficult to see each pattern of the y-direction electrode YP and the x-direction electrode XP.

  Since the capacitive touch panel thus configured is made of a polymer material formed by applying the y-direction electrode YP and the x-direction electrode XP, for example, a conventional touch panel formed of ITO or the like is used. Since it is superior in elasticity as compared with, it is possible to obtain a material that is resistant to mechanical wear and excellent in impact resistance. Similarly, the insulating film IN and the protective film PS are made of a material formed by coating, and have excellent elasticity as compared with a conventional film formed by, for example, CVD (Chemical Vapor Deposition). A product that is resistant to mechanical abrasion and excellent in impact resistance can be obtained.

<Touch panel controller>
FIG. 4 is a circuit diagram showing an embodiment of the configuration of the touch panel controller 3 used by being connected to the touch panel 100.

  4, the touch panel controller 3 includes, for example, an integration circuit 30 connected to the touch panel 100, an AD converter 40 connected to the integration circuit 30, and an arithmetic processing circuit 50 connected to the AD converter 40. It is composed of The integration circuit 30 is configured by integrating an integration capacitance (Cc) 32 and a reset switch 33 between input and output terminals of an operational amplifier 31 in parallel. The input terminal of the operational amplifier 31 is a node A connected to, for example, the x-direction electrode XP of the touch panel 100, and a current source I is connected to the node A. Electric charges generated in the terminal capacitance Cp and the finger contact capacitance Cf of the touch panel 100 are accumulated in the integral capacitance (Cc) 32. The output voltage of the output terminal (node B) of the operational amplifier 32 is determined by the ratio of the integration capacitance (Cc) 32 to (Cp + Cf). The ON / OFF of the reset switch 33 is controlled by a clock signal Vrst having a predetermined cycle, and the detection time is controlled. After the output from the integration circuit 30 is digitized through the AD converter 40, the arithmetic processing circuit 50 calculates the x coordinate of the finger touching the touch panel 100. Such a configuration is the same in a circuit connected to the y-direction electrode YP of the touch panel 100, and calculates the y-coordinate of the finger touching the touch panel 100.

  Note that, in the above-described configuration, a circuit that converts an AD conversion unit into time may be applied instead of the AD converter 40. Further, the touch panel controller 3 may have a configuration other than the configuration shown in FIG. 4. In short, the touch panel controller 3 may have a configuration capable of detecting a change in capacitance or charge.

  FIG. 5 is a timing chart showing an operation sequence of the integration circuit 30. (A) shows a clock signal Vrst for turning on the reset switch 33, (b) shows a voltage at the node B, (c) shows an output from the AD converter 40, and (d) shows a finger touching the touch panel 100. (In the figure, TC indicates contact, and NT indicates non-contact). The clock signal Vrst is output at times T0, T1, T2, and T3, indicating a non-contact state between T0 and T1, a contact state between T1 and T2, and a non-contact state between T2 and T3. The voltage of the node A (see FIG. 4) is determined by the time during which the current source I is charged, for example, to the terminal capacitance Cp of the x-direction electrode XP when the finger is not in contact. It is determined by the time required to charge the terminal capacitance Cp and the capacitance Cf at the time of contact. The voltage of the node B (see FIG. 4) becomes the ground level when the reset switch 22 is turned on by the clock signal Vrst. Here, the voltage at the node B at the time T2 when the finger is in contact is represented by V (T2), and the voltage at the node B at the time T1 when the finger is not in contact is represented by V (T1). The difference D is represented by a signal component, and is represented by the following equation (1).

V (T2) -V (T1) = ItCc / Cp-ItCc / (Cf + Cp)
= Cf / Cp / (Cf + Cp) Cc (1)
Here, Cp: terminal capacitance, Cf: capacitance at the time of finger contact, I: current value of the current source I, and Cc: integration capacitance of the integration circuit 30.

(Display device with touch panel)
FIG. 6 is an exploded perspective view showing one embodiment of a display device including the above-described touch panel 100, that is, a screen input type display device.

  As the display device, for example, a liquid crystal display panel PNL is used. In the liquid crystal display panel PNL, the TFT substrate SUB1 and the counter substrate SUB2 sandwiching the liquid crystal LC constitute an envelope of the liquid crystal display panel PNL. In this case, the TFT substrate and the counter substrate SUB2 may be glass substrates or substrates made of resin. A plurality of pixels arranged in a matrix are formed on the surface of the TFT substrate SUB1 on the liquid crystal LC side, and each of the pixels is independently driven by a thin film transistor (not shown) formed adjacent thereto. ing. A flexible substrate FPC is connected to the TFT substrate SUB1, and a signal is independently supplied to each pixel via the flexible substrate FPC. A lower polarizer POL1 is disposed on a surface of the TFT substrate SUB1 opposite to the liquid crystal LC, and an upper polarizer POL2 is disposed on a surface of the opposite substrate SUB2 opposite to the liquid crystal LC so that the behavior of the liquid crystal LC of each pixel can be visualized. Has become. Further, since each pixel of the liquid crystal display panel PNL is a non-light emitting element for controlling the amount of light transmission, a backlight BL is disposed on the surface of the liquid crystal display panel PNL opposite to the viewer.

The touch panel 100 is arranged on the surface of the liquid crystal display panel PNL on the observer side, and the display area of the liquid crystal display panel PNL can be viewed through the touch panel 100. The touch panel 100 has an x-direction electrode XP and a y-direction electrode YP formed on a surface of the substrate SUB opposite to, for example, the liquid crystal display device PNL, and a surface of the touch panel 100 on which the x-direction electrode XP and the y-direction electrode YP are formed. A protection plate PB made of, for example, acrylic is arranged on the side. Note that the touch panel 100 is bonded to the liquid crystal display panel PNL via an adhesive layer ADL.
FIG. 7 is a diagram illustrating a configuration in which a liquid crystal display module LDM is configured by the above-described liquid crystal display panel PNL, the liquid crystal driving circuit DR, the touch panel 100, and the touch panel controller 3, and is connected to the mobile device MM. The mobile device MM includes a processor CPU. Communication between the processor CPU and the touch controller 3 is performed by SPI, I2C, or the like, and communication between the processor CPU and the liquid crystal display driver DR is performed via an RGB interface or a CPU interface. Is to be done. As a result, the mobile device MM transmits initial setting data such as start-up, sampling frequency, and detection resolution to the liquid crystal display module LDM. Then, the detection data (x, y coordinate data, presence / absence of finger touch, etc.) is transmitted from the liquid crystal display module LDM to the mobile device MM, and the processor CPU in the mobile device MM is generated based on the position information detected by the touch panel 100. And is added to the display information of the liquid crystal display device PNL.

<Example 2>
FIG. 8 is a sectional view showing another embodiment of the touch panel of the present invention. FIG. 8 is a diagram corresponding to FIG.

  8, the configuration different from that of FIG. 1 is that the y-direction electrode YP is formed on one surface (upper surface in the drawing) of the substrate SUB, whereas the x-direction electrode XP is formed on the substrate SUB. It is formed on the other surface (the lower surface in the figure). Thus, the substrate SUB functions as an interlayer insulating film between the y-direction electrode YP and the x-direction electrode XP. When viewed in plan, the y-directional electrode YP and the x-directional electrode XP viewed through the substrate SUB have the same positional relationship as shown in FIG. On one surface of the substrate SUB, a protective film PS (indicated by a symbol PS (1) in the drawing) is formed so as to cover the y-direction electrode YP, and to cover the x-direction electrode XP on the other surface of the substrate SUB. A protective film PS (indicated by a symbol PS (2) in the figure) is formed. Even in such a case, the materials of the y-direction electrode YP, the x-direction electrode XP, and the protective films PS (1) and PS (2) are made of the materials shown in the first embodiment. .

<Example 3>
FIG. 9 is an exploded perspective view showing another embodiment of the display device of the present invention. FIG. 9 is a diagram corresponding to FIG.

  9 differs from FIG. 6 in that the x direction electrode XP and the y direction electrode YP of the touch panel 100 are formed on the surface of the substrate SUB on the liquid crystal display device PNL side. The touch panel 100 is bonded to the liquid crystal display device PNL through the adhesive layer ADL on the surface on which the x-electrode XP and the y-direction electrode YP are formed. In such a configuration, the substrate SUB can also serve to protect the x-direction electrode XP and the y-direction electrode YP, so that the touch panel 100 itself can be made thinner.

<Example 4>
FIGS. 10A and 10B are diagrams showing examples of devices to which the screen input type display device according to the present invention is applied. FIG. 10A shows a PDA, and a liquid crystal display panel PNL in which a touch panel 100 is arranged on the observer side is incorporated in a display section AR. FIG. 10B shows a mobile phone, and a liquid crystal display panel PNL in which a touch panel 100 is arranged on the viewer side is incorporated in a display unit AR thereof. It should be noted that the device to which the screen input type display device according to the present invention is applied is not limited to the device described above.

<Example 5>
In the above-described embodiment, a liquid crystal display panel is described as an example of the display device. However, another display device such as an organic EL device may be used.

SUB, SUB1, SUB2 ... substrate, YP ... y direction electrode, PDy ... pad part (y direction electrode), XP ... x direction electrode, PDx ... pad part (x direction electrode), WLy ... wiring ( (y-direction electrode), WLx (x-direction electrode), CN ... connector, IN ... insulating film, PS, PS (1), PS (2) ... protective film, PB ... protective plate, ADL ... Adhesive layer, POL1 Lower polarizing plate, POL2 Upper polarizing plate, LC Liquid crystal, FPC Flexible substrate, PNL Liquid crystal display panel, BL Backlight, LDM Liquid crystal display module, MM … Mobile device, DR… liquid crystal drive circuit, 3… touch panel controller, 30… integration circuit, 31… operational amplifier, 33… reset switch, 40… AD converter, 50… , 100 ...... electrostatic capacity type touch panel.

Claims (3)

An insulating substrate made of resin,
A plurality of first electrodes made of a transparent conductive film formed on the insulating substrate;
An insulating film formed on the plurality of first electrodes;
A plurality of second electrodes, which are formed on the insulating film, are made of a transparent conductive film, and intersect with the first electrodes;
In a method of manufacturing a capacitive touch panel including a protective film formed on the plurality of second electrodes,
A step of applying a photosensitive polymer material to the insulating substrate in the air and patterning by photolithography to form the first electrode;
A step of applying a liquid photosensitive polymer material on the insulating substrate including the first electrode in the air, patterning the liquid photosensitive polymer material by photolithography, and forming the insulating film;
A step of applying a photosensitive polymer material on the insulating film in the air and patterning by photolithography to form the second electrode;
Forming the protective film by coating the second electrode in the air, applying an organic resin material, and forming the protective film. The method of manufacturing a capacitive touch panel according to claim 1, wherein the protective film, the first electrode, and the second electrode have substantially the same refractive index. The method of claim 1, wherein the protective film is applied by screen printing or an inkjet method.

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