JP2018055360A - Touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel capable of preventing damage to an electrode surface at the time of shipment without changing a touch panel device manufacturing process.SOLUTION: A protection TAC film 4 transmitting UV light with a waveform necessary to cure a UV curable adhesive on an adhesion region with a display device 20 is stuck to a surface of a sensor unit 2 composed of a first electrode 13 and a second electrode 14 formed on a rear surface 11b of a substrate 11. The protection TAC film 4 comprises a film body 4a transmitting UV (UVA or UVB) light, an adhesive layer 4b, and a hard coat layer 4c of a material having the same line as a resin type which is a main component of the UV curable adhesive used when direct bonding with the display device 20 is performed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projected capacitive touch panel capable of detecting multiple fingertips.

  In recent years, electronic devices such as mobile phones, smart devices (for example, tablet terminals and electronic book readers), car navigation systems, etc. have the advantage of being able to operate intuitively and having excellent durability as a form of interface. A display device (touch panel device) including a panel (touch panel) having a touch sensor function is mounted.

  The touch panel is a position input device that detects a touch by an indicator such as a finger or a stylus, and specifies the coordinates of the touch position. In recent years, when the fingertip approaches, the capacitance change of the electrode in the vicinity of the touch panel is two vertical and horizontal. There is an increasing demand for a projected capacitive touch panel that detects a position coordinate on the touch panel from an electrode array.

  The following Patent Document 1 discloses a capacitive touch panel. This touch panel is formed with a plurality of detection electrodes for detecting that a conductor has approached the glass substrate surface, and wiring electrodes for electrically connecting to the detection electrodes and transmitting detection signals to an external circuit. The sensor part is provided on the back side of the glass substrate.

JP 2011-90443 A

  By the way, after manufacturing a touch panel as disclosed in Patent Document 1, when shipping to a delivery destination, a panel surface is used for the purpose of protecting the front surface (touch surface side) and back surface (film surface side of the sensor unit) of the panel. A low-adhesive protective film is attached to the back side. Then, the supplier who delivered the product proceeds with the manufacturing process for peeling the protective film and mounting it on various devices such as a liquid crystal panel.

However, if the protective film is delivered with the protective film attached, the protective film is peeled off and used by the supplier, but at this time, the following problems may occur.
(Problem 1)
Since the touch panel has low resistance to ESD (electro-static discharge), if the process proceeds to the manufacturing process with the protective film peeled off, the sensor may break down due to static electricity generated in the process. It is difficult to ensure sufficient sex.
(Problem 2)
In the process of manufacturing a touch panel device, the touch panel is handled in a state where the protective film is peeled off, so that the sensor surface is exposed and a minute scratch may be attached during the process.
(Problem 3)
For example, in the case of manufacturing an in-vehicle car navigation system as a touch panel device, an optical resin such as a UV curable adhesive (for example, OCR (Optically Clear Resin)) or OCA (Optically An optical adhesive sheet such as Clear Adhesive) is used, which is applied to the sensor surface side and directly bonded to the LCD, and then cured by irradiation with UV (peak wavelength is about 365 nm).
Therefore, if a PET film is pasted as a protective film on the sensor surface, a phase difference occurs in the film thickness direction between the sensor / display device, and rainbow unevenness occurs locally. In addition, when a general TAC film is used as the protective film, the UV curable adhesive used for direct bonding cannot be cured because it does not transmit UV.

  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 that ensures product quality at the time of product delivery and does not interfere with the touch panel device manufacturing process after delivery. Yes.

To achieve the above object, according to a first aspect of the present invention, a column electrode extending in a first direction and a column electrode extending in a second direction crossing the first direction are provided on one side of the substrate. And a sensor part having an electrode structure formed with
In the projected capacitive touch panel in which a UV curable adhesive is applied to the sensor unit and bonded to the display device,
The touch panel is characterized in that a protective TAC film having UV transparency is attached to at least an adhesion region with the display device on the surface of the sensor unit.

  A second aspect according to the present invention is the touch panel according to the first aspect, wherein the protective TAC film further has a thickness direction retardation of substantially zero.

  According to a third aspect of the present invention, in the touch panel according to the first or second aspect, the protective TAC film has the same resin type as the UV curable adhesive on the adhesive surface side with the display device. A touch panel, wherein a hard coat layer of a system is formed.

  According to the present invention, a UV curable adhesive is used for direct bonding of a touch panel and a display device in a touch panel device manufacturing process while covering fine scratches caused by transportation at the time of delivery and ensuring product quality. It can be cured.

  Further, since the protective TAC film has substantially zero retardation in the thickness direction of the film, no retardation occurs in the film thickness direction between the sensor / display device, and local rainbow unevenness does not occur. .

  In addition, the surface of the protective TAC film is provided with a hard coat layer of the same type of resin as the main component of OCR and OCA used as a UV curable adhesive. Adhesive compatibility with the UV curable adhesive can be improved.

It is a schematic sectional drawing which shows the layer structure of the principal part of the touchscreen which concerns on this invention. It is the graph which compared the TAC film for protection with UV transmittance.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited by this embodiment, and other forms, examples, operation techniques, and the like that can be considered by those skilled in the art based on this form are all included in the scope of the present invention. To do.

  In the present specification, in the following description with reference to the accompanying drawings, when the words “up”, “down”, “left”, and “right” are used to indicate directions and positions, this is shown in FIG. Matches top, bottom, left, and right.

  The touch panel 1 according to the present embodiment is a projected capacitance capable of multipoint detection of a fingertip that detects a position coordinate on the touch panel 1 from two vertical and horizontal electrode rows, as the fingertip approaches the touch panel 1. The method is adopted.

  The electrode structure of the touch panel 1 according to the present invention may be a projected capacitive touch panel that is directly bonded to the display device 20 (various display devices such as a liquid crystal display and an EL display). The electrode structure of the part 2 and the attachment structure of the sensor part 2 to the housing part 3 are not particularly limited.

First, the configuration of the touch panel 1 according to the present invention will be described.
The shape of the touch panel 1 of the present embodiment can be arbitrarily designed according to the shape of the touch panel device to be manufactured, such as a rectangle (rectangle, square), a circle, an ellipse, or a polygon.

  As shown in FIG. 1, the touch panel 1 of this embodiment is a structure which employ | adopted OGS (One Glass Solution), and the back surface (surface which opposes the surface 11b used as an operation surface) 11a which has translucency 11a The film-shaped sensor part 2 in which the electrode part 12 composed of the first electrode 13 and the second electrode 14 formed on the substrate is disposed, the housing part 3 into which the substrate 11 is fitted, and the surface of the sensor part 2 (that is, And a protective TAC film 4 for protecting the first electrode 13 and the surface of the second electrode 14 in the electrode portion 12.

  The substrate 11 serving as the base of the sensor unit 2 is formed of a light-transmitting insulating material, and for example, a glass type is used. As the glass substrate 11, for example, alkali-free glass, soda lime glass, aluminosilicate glass, or the like is used.

  On the back surface 11 a of the substrate 11, the first electrode 13 and the second electrode 14 as the electrode portion 12 are formed.

  The first electrode 13 is formed by, for example, etching a transparent conductive material such as ITO (Indium Tin Oxide) after patterning a resist using a photolithography technique or the like, for example, the first direction X direction (front / depth in the figure). The column electrodes are arranged in a plurality of directions. Similarly to the first electrode 13, the second electrode 14 is, for example, in the second direction by etching a transparent conductive film such as ITO (Indium Tin Oxide) after patterning a resist using a photolithography technique or the like. Formed as a plurality of column electrodes arranged in the Y direction (left and right direction in the figure).

The method for forming the electrode portion 12 will be described. First, a plurality of first electrodes 13 extending in the X direction and a plurality of electrode elements arranged in the Y direction in a divided state are formed on the back surface 11a of the substrate 11. Form.
Next, the insulating layer 15 is formed on the first electrode 13 at the intersection of the first electrode 13 and the second electrode 14. The insulating layer 15 electrically insulates between the first electrode 13 and the second electrode 14 and is made of an insulating material such as acrylic resin.
Next, a plurality of electrode elements are connected by a bridge structure in the Y direction across the first electrode 13 to form the second electrode 14. At that time, the adjacent second electrodes 14 are wired so as to pass over the insulating layer 15 by a bridge structure.
Then, when the first electrode 13 and the second electrode 14 are formed, the overcoat layer 16 is formed on the surface thereof by a well-known film forming method such as a screen printing method to form the sensor unit 2.

  In the above-described method of forming the electrode portion 12, the bridge structure is used for the second electrode 14 on the back surface 11a of the substrate 11. However, the first electrode 13 and the second electrode 14 are reversed, A bridge structure may be used for one electrode 13. In addition, since it is sufficient that at least the intersection of the first electrode 13 and the second electrode 14 is insulated, an insulating layer 15 is formed on the entire surface of one of the electrodes (the first electrode 13 or the second electrode 14). The other electrode (the second electrode 14 or the first electrode 13) may be formed on the insulating layer 15.

  As shown in FIG. 1A, the first electrode 13 and the second electrode 14 formed on the substrate 11 by the above-described forming method are each drawn out to the end of the substrate 11 by the lead wiring 17. The wiring is connected to a control IC (control circuit) (not shown).

  The lead-out wiring 17 is a lead-out from each end of the first electrode 13 and the second electrode 14 in the lead-out wiring area E2 outside the operation area E1, and is, for example, Ni (nickel) or Nb (niobium). , Cu (copper), Mo (molybdenum), MAM (Mo / Al / Mo), APC (alloy containing Ag, Pd, Cu) and the like are formed by sputtering, and a predetermined pattern is formed by etching. It is formed up to the end of the substrate 11.

  Thus, in order to maintain the accuracy as the position sensor, the sensor unit 2 has an XY matrix shape on the substrate 11 in a state where the first electrode 13 and the second electrode 14 made of linear electrodes are electrically insulated. It is possible to independently detect which X direction electrode and which Y direction electrode, not where on which electrode, and calculate the position from the intersection.

  Further, at the outer edge of the back surface 11a of the substrate 11, the wiring structure of the sensor unit 2 from the operation surface 11b side covers the lead-out wiring region E2 of the lead-out wiring 17 drawn out from the first electrode 13 and the second electrode 14. A decorative layer 18 is provided so as not to be visually recognized. The decorative layer 18 is made of, for example, a polyester resin, an epoxy resin, a phenol resin, a silicone resin, a polyimide resin, and the like. The concealment ratio, heat resistance, and pressure resistance for concealing the lead wiring routed from each electrode in the lead wiring region E2 A material excellent in property and chemical resistance is preferable. In addition, the decorative layer 18 is color-adjusted so as to match the color of the casing 3 by mixing a pigment whose content is adjusted so as to ensure insulation.

  The housing | casing part 3 is comprised with thermoplastic synthetic resins, such as general purpose plastics and engineering plastics, for example. The housing 3 is framed by cutting out according to the shape of the outer edge of the substrate 11 with the operation surface 11b side as a surface, and when the substrate 11 provided with the sensor 2 is fitted, the housing 3 3 and the operation surface 11b of the substrate 11 are flush with each other and are seamless.

  In addition, the housing | casing part 3 shall be the structure which carried out insert injection molding in the state which pinched | interposed the outer peripheral part of the board | substrate 11 corresponded to the area | region (namely, extraction wiring area | region E2) in which the decoration layer 18 is formed. You can also. By adopting such a configuration, it is not necessary to form the decorative layer 18 that is difficult to adjust the hue with the casing 3, and the effect of preventing the substrate 11 from being detached from the casing 3 due to dropping or the like. Can play.

  The protective TAC film 4 is a TAC (Tri-Acetyl Cellulose) film that is attached to the surface of the sensor unit 2 (the surface facing the display device 2 and to which the UV curable adhesive is applied). The film body 4a, the adhesive layer 4b, and the hard coat layer 4c are provided. Since the protective TAC film 4 has a function of transmitting UV (UVB or UVA), when the touch panel 1 and the display device 20 are directly bonded, the protective TAC film 4 is attached to the sensor unit 2. UV curable adhesive (for example, an optical adhesive such as OCR, an optical adhesive sheet such as OCA) can be cured by irradiating UV from the surface 11b side of the substrate 11.

As shown in FIG. 2, when the transmittance of UV (peak wavelength is about 365 nm) in the conventional TAC film and the protective TAC film 4 of the present invention is compared, the conventional TAC film can obtain the UV transmission amount necessary for curing. However, it can be confirmed that the protective TAC film 4 used in the present invention transmits a sufficient amount of UV to cure the UV curable adhesive.
Therefore, even if the protective TAC film 4 is attached to the surface of the sensor unit 2, the irradiated UV is transmitted through the UV curable adhesive applied for direct bonding to the display device 20, and is reliably cured. be able to.

Further, the protective TAC film 4 has substantially zero retardation in the thickness direction of the film, which is expressed in proportion to the intrinsic sub-refraction and molecular light distribution of the film material. Thereby, the local rainbow nonuniformity which arises when a PET film is stuck as a protective film, for example is not generated.

  As the protective TAC film 4 having such properties, for example, trade name “Z-TAC (registered trademark)” manufactured by FUJIFILM Corporation, trade name “Zero Tac (registered trademark)” manufactured by Konica Minolta Co., Ltd., etc. It has been known.

  In addition, when the protective TAC film 4 is attached to the surface of the sensor unit 2, the adhesive layer 4b cancels out the fine scratches and unevenness on the surface of the sensor unit 2, thereby maintaining the product quality before and after delivery. can do. For this reason, when the overcoat layer 16 is formed, it is not a photoresist system in which fine unevenness on the surface is extremely small at the time of film formation, but the equipment cost is high, and some fine unevenness occurs, but the equipment cost is low. It is possible to positively adopt a film forming method by a screen printing method.

  Furthermore, a hard coat layer 4c is formed on the surface of the protective TAC film 4 (the surface facing the display device 20 when attached to the sensor unit 2). The hard coat layer 4c is made of the same type of material as the resin type that is the main component of OCR or OCA used as a UV curable adhesive. For example, when the UV curable adhesive is acrylic, the same acrylic PMMA is used as the hard coat layer. Thus, adhesive compatibility becomes favorable by making the resin kind of the hard-coat layer 4c and UV curable adhesive into the same system | strain.

  In addition, when the protective TAC film 4 is attached to the sensor unit 2 and an EMS (Electromagnetic Susceptibility) pressure resistance test of the touch panel 1 is performed as a quality evaluation test, the protective TAC film depends on the electrode structure of the sensor unit 2. The pressure resistance performance can be improved by about 5 to 10 kV compared to the product before 4 is attached.

Next, the manufacturing process of the touch panel 1 according to the present invention will be described.
First, the decoration layer 18 is formed in a portion corresponding to the lead-out wiring region E2 on the back surface 11b of the substrate 11. Next, after the sensor part 2 including the first electrode 13 and the second electrode 14 is formed into a film so that the lead-out wiring 17 is formed on the surface of the decorative layer 18, the sensor part 2 is formed by screen printing. An overcoat layer 16 is formed on the surface.

  Next, the protective TAC film 4 is attached to the surface of the sensor unit 2. At this time, even if fine scratches are generated on the surface of the sensor unit 2, the uneven step is offset by the adhesive layer 4b, and appearance defects can be eliminated.

  Further, since the protective TAC film 4 is attached to at least an adhesive surface (corresponding to a region to which the UV curable adhesive is applied) on the surface of the sensor unit 2, the present invention is provided at the delivery destination. When the touch panel 1 and the display device 20 are bonded to each other, UV irradiated from the surface 11b side of the substrate 11 reaches the UV curable adhesive and can be reliably cured.

  As described above, the touch panel 1 of the present embodiment is a protective TAC that transmits UV having a wavelength necessary to cure the UV curable adhesive at least in the adhesion region with the display device 20 on the surface of the sensor unit 2. The film 4 is stuck on the surface of the sensor unit 2.

For this reason, the UV curable adhesive is cured when the touch panel 1 and the display device 20 are directly bonded in the manufacturing process of the touch panel device while covering fine scratches caused by transportation at the time of delivery and ensuring product quality. Can be made.

  Further, since the protective TAC film 4 has substantially zero phase difference in the thickness direction of the film, no phase difference occurs in the film thickness direction between the sensor / LCD and local rainbow unevenness does not occur. .

  Further, the hard coat layer 4b formed on the surface of the protective TAC film 4 (that is, the surface facing the display device 20 when attached to the sensor unit 2) is used as an OCR used as a UV curable adhesive. In addition, by using a material of the same system as the resin type that is the main component of OCA, it is possible to improve the adhesive compatibility between the hard coat layer 4c and the UV curable adhesive when direct bonding is performed.

DESCRIPTION OF SYMBOLS 1 ... Touch panel 2 ... Sensor part 3 ... Housing | casing part 3a ... Front surface 3b ... Back surface 4 ... TAC film for protection (4a ... Film main body, 4b ... Adhesive layer, 4c ... Hard-coat layer)
11 ... Substrate 11a ... Back (operation facing surface)
11b ... surface (operation surface)
12 ... Electrode part
DESCRIPTION OF SYMBOLS 13 ... 1st electrode 14 ... 2nd electrode 15 ... Insulating layer 16 ... Overcoat layer 17 ... Lead-out wiring 18 ... Decorating layer 20 ... Display apparatus E1 ... Operation area E2 ... Lead-out wiring area

Claims (3)

A sensor unit having an electrode structure in which a first electrode extending in a first direction and a column electrode extending in a second direction intersecting the first direction are formed on one side of the substrate;
In the projected capacitive touch panel in which a UV curable adhesive is applied to the sensor unit and bonded to the display device,
A touch panel, wherein a protective TAC film having UV transparency is attached to at least an adhesive region with the display device on a surface of the sensor unit.   The touch panel according to claim 1, wherein the protective TAC film further has a thickness direction retardation of substantially zero.   3. The hard coat layer of the same type as the resin type of the UV curable adhesive is formed on an adhesive surface side of the protective TAC film with the display device. Touch panel.

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