JP5668390B2 - Display device with touch panel - Google Patents

Description

  The present invention relates to a display device with a touch panel in which a touch panel is mounted on the observation side of a display panel.

  Depending on the input principle of the touch panel, there are optical, resistive, capacitive, ultrasonic, electromagnetic induction, and other systems. Recently, a capacitance method capable of multi-touch is used. As a configuration of a display device equipped with this capacitive touch panel, a display panel such as an LCD, a shield layer for preventing noise from the display panel is provided on the observation side of the display panel, and the observation side thereof is provided. A touch panel is installed, and a cover lens or the like is mounted on the front side of the touch panel as a part where a finger touches through an adhesive layer or the like. The principle of operation of this capacitive touch panel is to detect changes in the capacitance of the electrodes in the touch panel caused by the finger touching the outermost surface layer. , Digitized data about the movement of the finger, and is designed to work.

  This capacitive touch panel requires electrodes in two directions, the X direction and the Y direction perpendicular to it, and detects the coordinates by detecting the change in capacitance when touched by a finger. The touch position and touch operation are recognized. Further, the X electrode layer and the Y electrode layer are not in contact with each other, and are laminated via an insulating film. A transparent conductive material is mainly used for the X electrode and the Y electrode, and an electrode layer is formed by depositing and patterning a conductive material on each substrate. The patterning shape of the electrode includes a linear shape and a diamond shape.

  In addition, the X electrode layer and the Y electrode layer may be formed and patterned on a base material and bonded together via an adhesive layer, or the conductive material may be formed and patterned on both sides of one base material. . In most cases, ITO (indium tin oxide), which is a transparent conductive material, is used as the electrode material.

  The capacitive touch panel as described above is very sensitive to noise from peripheral components because it needs to detect a precise change in capacitance. Therefore, in a display device equipped with a touch panel, a shield layer for blocking electrical noise from the display panel is provided between the touch panel and the display panel. The material of the shield layer is required to be transparent and conductive. Therefore, as the material, ITO, which is the same material as the electrode of the touch panel, is mostly used. The ITO film of the shield layer does not need to be patterned and is formed on the entire surface of the substrate.

  However, since the ITO film has a relatively high b * value in the L * a * b * color system and tends to be yellowish, if an ITO film is used for the shield layer, a display equipped with a capacitive touch panel In the apparatus, when the ITO layer includes the ITO layer of the touch panel portion, three layers are laminated, and there is a problem that the color becomes more yellowish and the optical characteristics deteriorate. In addition, ITO requires an expensive vacuum sputtering apparatus to form the film, and therefore, further improvement in cost and productivity is demanded.

  As a countermeasure to the above problem, there is an example in which the electrode structure in the capacitive touch panel is devised and a shield layer is incorporated in the touch panel (Patent Document 1). However, this method is a technique different from the present invention because the structure of touch panel and shield layer and the structure of wiring are different from the present invention.

JP 2010-44453 A

  The present invention uses a base material coated with a conductive polymer that can be coated with a coater or the like on a shield layer mounted between a touch panel and a display panel, so that optical characteristics are good, low cost, and high production. An object is to provide a display device with a touch panel.

In order to solve the above problems, the invention according to claim 1 is a display device equipped with a touch panel on the observation side of the display panel, provided with a shield layer for preventing electrical noise therebetween, the shield layer A transparent conductive film containing a conductive polymer, wherein the touch panel includes a conductive film layer formed using indium tin oxide and has a positive b * value in the L * a * b * display system of the touch panel. is a value, the conductive polymer comprising the said shield layer, polyethylenedioxythiophene or polyaniline der is, the shield layer to have a thickness of the b * value in the shielding layer and the negative value and the features and to filter touch panel display device with.
The invention according to claim 2, wherein the touch panel is a touch panel display unit according to claim 1, characterized in that a touch panel of the projected capacitive type.
The invention according to claim 3 is characterized in that the b * value in the L * a * b * display color system in the display device with a touch panel is 1.0 or less. A display device with a touch panel was obtained.

  The present invention uses a conductive polymer. Many conductive polymers are bluish with a negative b * value. And since it is easy to choose this, it becomes an effective measure which prevents a touch panel from becoming yellowish. Thereby, it is possible to provide a touch panel with good optical characteristics. In addition, since it can be dispersed mainly in liquid, it can be applied by wet (WET) without the need for expensive vacuum equipment required for ITO film formation, improving productivity and reducing costs. It is possible to plan.

Sectional drawing which shows the structure of the display apparatus with a touchscreen which concerns on embodiment of this invention. Sectional drawing which shows the structure of the touchscreen member used for the display apparatus with a touchscreen which concerns on embodiment of this invention. Sectional drawing at the time of patterning the electrode of the touchscreen member used for the display apparatus with a touchscreen which concerns on embodiment of this invention. The top view of the patterning example of the electrode of the touchscreen used for the display apparatus with a touchscreen which concerns on embodiment of this invention. Sectional drawing which shows the structure of the touchscreen used for the display apparatus with a touchscreen which concerns on embodiment of this invention. The top view of the touchscreen electrode used for the display apparatus with a touchscreen which concerns on embodiment of this invention. Sectional drawing which shows another structure of the touchscreen used for the display apparatus with a touchscreen which concerns on embodiment of this invention. Sectional drawing which shows the structure of the shield layer of the display apparatus with a touchscreen which concerns on embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. FIG. 1 is a cross-sectional view illustrating a configuration of a display device with a touch panel according to an embodiment of the present invention. The display device with a touch panel includes a display panel 30, a touch panel 10 that is configured on the observation side, a front panel layer 40 that is laminated on the surface on the further observation side of the touch panel 10 via an adhesive layer 50, The shield layer 20 is interposed between the display panel 30 and the touch panel 10.

  FIG. 2 is a cross-sectional view showing the configuration of the electrode-attached film constituting the touch panel 10. In the touch panel 10, first, a UV (ultraviolet) curable resin layer 12 as a photocurable resin is laminated on a base material 11. Lamination of the UV curable resin layer to the substrate 11 may be provided on one side of the substrate 11 or on both sides of the substrate 11. FIG. 2 shows a case where the UV curable resin layer 12 is provided on one side of the substrate 11. On the UV curable resin layer 12, a conductive film layer 14 serving as an electrode is laminated. In this case, it is preferable to provide the optical functional layer 13 between the cured resin layer 12 and the conductive film layer 14.

  FIG. 3 shows a cross section of the laminate 15 in which the conductive film layer is patterned. As patterning of the conductive film layer, for example, a conductive pattern portion and a non-conductive pattern portion are formed through steps of resist coating, exposure, etching, and resist peeling. As a patterning method, any method such as photolithography, screen printing, laser patterning, etc. may be used. Examples of electrode patterning include a diamond shape and a linear shape. In the present invention, a diamond shape is often used. FIG. 4 shows a state in which a conductive film layer is patterned in a rhombus shape as viewed from above.

  In the form shown in FIG. 5, two stacked bodies 15 are stacked via the adhesive layer 16, and this becomes the touch panel 10 having two electrode layers. When the conductive film layer is patterned in a rhombus shape, the conductive pattern portion of one conductive film layer 14 and the conductive pattern portion of the other conductive film layer 14 ′ are stacked so as not to overlap each other. Taking the patterning shown in FIG. 4 as an example, a pattern rotated by 90 ° C. is overlaid so as to be as shown in FIG. 6 when viewed from above. As a result, either one can detect a change in capacitance in the X direction and the other can detect a change in Y direction.

  Next, a touch panel 10 ′ having another configuration of the touch panel unit shown in FIG. 7 will be described. This is formed by laminating UV curable resin layers 12 and 12 ′ as photocurable resins on both sides of the substrate 11. Conductive film layers 14 and 14 'are laminated on the UV curable resin layers 12 and 12', respectively. It is also preferable to provide optical functional layers 13 and 13 'between the cured resin layers 12 and 12' and the conductive film layers 14 and 14 '. Subsequently, the conductive film layers 14 and 14 'are patterned. For this patterning, for example, a conductive pattern portion and a nonconductive pattern portion are formed through steps of resist coating, exposure, etching, and resist stripping. In the case of patterning in a diamond shape as shown in FIG. 4, the conductive pattern portions of the conductive film layers 14 and 14 ′ after etching are not overlapped. FIG. 7 shows a cross-sectional state of the touch panel 10 ′.

  As the substrate 11, transparent glass and plastic film are used. The plastic film is not particularly limited as long as it has sufficient strength in the film-forming process and the subsequent process and has a smooth surface. For example, polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polycarbonate film, Examples include ether sulfone films, polysulfone films, polyacrylate films, and polyimide films. These base materials may contain additives such as an antioxidant, an antistatic agent, an ultraviolet light inhibitor, a plasticizer, a lubricant, and an easy adhesive. In order to improve the adhesion, corona treatment or low temperature plasma treatment may be performed.

  The UV curable resin layers 12 and 12 'as the photo curable resin are not particularly limited as long as they have transparency and appropriate hardness and strength. Desirably, a material whose refractive index is equal to or close to that of the substrate 11 is selected. Further, as the resin layers 12 and 12 ′, not only a photocurable resin but also a cured resin such as a thermosetting resin can be used.

  As the optical functional layer 13, when an inorganic compound is used, oxide, sulfide, fluoride, nitride, and the like can be given. Specific examples include magnesium oxide, silicon dioxide, magnesium fluoride, aluminum fluoride, titanium oxide, zirconium oxide, zinc sulfide, tantalum oxide, zinc oxide, indium oxide, niobium oxide, and tantalum oxide. Since these inorganic compounds have different refractive indexes depending on the material and film thickness, it is possible to adjust the optical characteristics by forming a specific material with a specific film thickness. Further, the optical functional layer 13 is not limited to one layer, and may be a plurality of layers.

  Examples of the conductive layers 14 and 14 'include indium oxide, zinc oxide, tin oxide, or mixed oxides thereof, and those added with other additives. However, it is not limited thereto. The most frequently used touch panel is indium tin oxide (ITO).

  As shown in FIG. 1, the touch panel 10 or 10 ′ and the display panel 30 are assembled via the shield layer 20. The shield layer 20 here is a layer that is incorporated in order to prevent electrical noise from the display panel from being applied to the touch panel unit 10 or 10 ′, and needs to be transparent and conductive.

  An example of the configuration of the shield layer 20 in the present invention is shown in FIG. A conductive film layer 22 is laminated on the substrate 21. A UV curable resin layer 23 may be interposed between the base material 21 and the conductive film layer 22 as a curable resin layer.

  As the substrate 21, transparent glass and plastic film are used. The plastic film is not particularly limited as long as it has sufficient strength in the film-forming process and the subsequent process and has a smooth surface. For example, polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polycarbonate film , Polyether sulfone film, polysulfone film, polyacrylate film, polyimide film and the like. These base materials may contain additives such as an antioxidant, an antistatic agent, an ultraviolet ray inhibitor, a plasticizer, a lubricant, and an easy adhesive. In order to improve adhesion, corona treatment or low-temperature plasma treatment may be performed.

  In the embodiment of the present invention, a conductive polymer is used as the conductive material used for the conductive film layer 22. As the conductive polymer, a π-conjugated polymer is used. Examples include polyacetylene, polydiacetylene, polyaniline, polyparaphenylene, polyparaphenylene vinylene, polythiophene, polyethylene dioxythiophene, polyfuran, polypyrrole, polyphenylene sulfide, polypyridyl vinylene, and polyazine. These may use only 1 type and may use it in combination of 2 or more type according to the objective. Among them, polyethylenedioxythiophene has a surface resistance of several hundreds Ω / □ and relatively good transparency. The b * value is negative and slightly bluish. Further, it can be suitably used as one that does not deteriorate the color of the entire display panel.

  As a method of laminating the conductive film layer 22 on the substrate 21, a spin coating method, a roller coating method, a bar coating method, a dip coating method, a gravure coating method, a curtain coating method, a die coating method, a spray coating method, a doctor coating method, It is applied by a coating method such as a kneader coating method or a coating method such as a screen printing method, a spray printing method, an ink jet printing method, a relief printing method, an intaglio printing method, a lithographic printing method.

  It is preferable that the conductive polymer used for the conductive film layer 22 is in a liquid state according to the coating method. In order to make it liquid, it is preferable to use it dissolved or dispersed in water or an organic solvent such as alcohol, ether, ketone, ester, hydrocarbon, halogenated hydrocarbon, amide and the like. Among these, solvents such as water, methanol, ethanol, and isopropyl alcohol can be easily used in terms of cost. In this case, an additive such as a dispersant or a surfactant may be added to improve the dispersibility of the polymer, an additive may be added to increase the film strength of the conductive film, or film hardening may be promoted. You may add the hardening | curing agent for.

  As a method for curing the film of the conductive film 22, it can be cured by a curing means such as thermal curing or UV curing depending on the type of π-conjugated polymer used and the type of curing agent added.

  The π-conjugated polymer described above does not exhibit conductivity by itself, and may have conductivity by adding a positive or negative charge to the π-conjugated polymer by adding a dopant. Therefore, it is also preferable to add a dopant. For example, in the case of polydioxythiophene, polystyrene sulfonic acid is generally added as a dopant.

  As the b * value of the conductive film layer 22 increases in the negative direction, the bluish color becomes stronger and the yellow color is effectively suppressed. The b * value can be controlled by changing the film thickness of the conductive polymer film, and the conductive polymer film having the most appropriate film thickness can be applied depending on the yellowness of the touch panel.

  As the structure of the display panel 30, for example, in the case of an LCD display panel, a color filter in which a switching element for driving liquid crystal is arranged and an electrode layer is provided (array substrate) and an opposing electrode layer is formed. The substrate is configured with a liquid crystal layer sandwiched between them, and an extremely common display panel in which a polarizing plate is attached to each of the array substrate and the color filter substrate is used. The driving method of the display panel 30 is not particularly limited, and an IPS, TN, VA, etc. LCD display is used. The structure of the display panel 30 is not limited to the above structure as long as the display panel can be provided with a touch panel on the viewing side of the display panel.

  Examples of the present invention are shown below, but the technical scope of the present invention is not limited to these examples.

  A UV curable resin was applied on a PET (polyethylene terephthalate) substrate (125 μm), and Nb 2 O 3 (film thickness 10 nm) and SiO 2 (film thickness 50 nm) were vacuum-deposited thereon, and ITO (film thickness 40 nm) was further formed thereon. . A resist was applied to the ITO layer by photolithography, and after curing by UV irradiation, etching with hydrochloric acid (0.1%) and stripping of the resist with sodium hydroxide solution (1%) were performed to pattern the conductive film. Two sheets of this conductive film were bonded together with an adhesive to make a touch panel.

  In addition, a UV curable resin is applied onto a PET substrate (125 μm), and a polyethylenedioxythiophene (PEDOT) dispersion containing polystyrene sulfonic acid as a dopant is applied thereon with a micro gravure coater and passed through an oven at 100 ° C. The solvent was dried and cured (film thickness 100 nm). This conductive film was used as a shield layer on the side opposite to the observation side of the touch panel, and the color tone b * value was measured from the observation side of the touch panel.

Comparative example

  A UV curable resin was applied on a PET substrate (50 μm), and ITO (film thickness 40 nm) was vacuum formed thereon. Using this conductive film as a shield layer, it was installed on the side opposite to the observation side of the touch panel described in Example 1, and the color tone b * value was measured from the observation side of the touch panel.

Table 1 shows the measurement results of the b * value. According to Table 1, in the case of the comparative example, the ITO film overlapped with the touch panel portion and the shield layer so that the b * value was high and yellowish. On the other hand, in the case of the example, b * when combined with the touch panel is a value close to zero as compared with the case of the comparative example, resulting in the suppression of yellowness.

10: Touch panel 10 ': Touch panel 11: Substrate 12: UV curable resin layer 12': UV curable resin layer 13: Optical functional layer 13 ': Optical functional layer 14: Conductive layer,
14 ': Conductive film layer 15: Laminated film with electrode after etching 16: Adhesive layer 20: Shield layer 21: Base material 22: Conductive film layer 23: UV cured resin layer 30: Display panel 40: Adhesive layer 50: Front panel

Claims (3)

In a display device with a touch panel provided with a touch panel on the observation side of the display panel,
The display panel and provided with a shield layer for preventing electrical noise between the touch panel, Ri transparent conductive film der including the shield layer is a conductive polymer,
The touch panel includes a conductive film layer formed using indium tin oxide, and the b * value in the L * a * b * display color system in the touch panel is a positive value.
The conductive polymer containing the said shield layer is a polyethylene dioxythiophene or polyaniline, the shielding layer, wherein the Rukoto to have a thickness to the b * values a negative value in the shield layer Display device with touch panel. The display device with a touch panel according to claim 1, wherein the touch panel is a projected capacitive touch panel.   3. The display device with a touch panel according to claim 1, wherein a b * value in an L * a * b * display color system in the display device with a touch panel is 1.0 or less.

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