KR20210128752A - Touch sensor stack structure and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a touch sensor laminate with improved mechanical stability and reliability, and a manufacturing method thereof. In the manufacturing method of the touch sensor laminate, a touch sensor structure including a base layer, sensing electrodes formed on the base layer, and pads connected to the sensing electrodes on the base layer is prepared. A conductive adhesive film is attached to upper portions of the pads and the end of the base layer adjacent to the pads. The ends of the conductive adhesive film and the base layer are cut together. A circuit connection structure is bonded to the conductive adhesive film. After attaching the conductive adhesive film, a part of the conductive adhesive film attached to a margin area is cut together with the base layer so that a bonding structure with a fine line width can be implemented.

Description

TOUCH SENSOR STACK STRUCTURE AND METHOD OF MANUFACTURING THE SAME

The present invention relates to a touch sensor laminate and a method for manufacturing the same. More particularly, it relates to a touch sensor laminate including a touch sensor layer and a bonding structure, and a method for manufacturing the same.

With the recent development of information technology, demands for the display field are also presented in various forms. For example, various flat panel display devices with features such as thinness, light weight, and low power consumption, for example, a liquid crystal display device, a plasma display panel device, Electroluminescent display devices, organic light-emitting diode display devices, and the like are being studied.

On the other hand, a touch panel or a touch sensor, which is an input device attached to the display device to input a user command by selecting instructions displayed on the screen with a human hand or an object, is combined with the display device to provide an image display function and Electronic devices in which an information input function is implemented are being developed.

For example, the touch panel includes sensing electrodes and pads applying a signal to the sensing electrodes. The pads may be electrically connected to a circuit member for applying a driving signal. In addition, an optical film of a display device such as a polarizing plate may be laminated on the touch panel.

Recently, as the area of the light blocking part or the bezel part of the display device is decreased and the area of the display area is gradually increased, the space for interconnecting the pad and the circuit member or performing the bonding process is also decreasing. When the bonding process is performed in a limited space, defects such as damage to the substrate, pad, etc. in the touch panel, misalignment of the pad/circuit member, etc. may occur.

For example, recently, as in Korean Patent Registration No. 10-2078385, a display device with an integrated touch screen has been actively developed. However, the process characteristics for improving the reliability of the above-described bonding process are not considered.

Korean Patent No. 10-2078385

One object of the present invention is to provide a touch sensor laminate having improved mechanical stability and reliability, and a method for manufacturing the same.

1. Preparing a touch sensor structure including a base layer, sensing electrodes formed on the base layer, and pads connected to the sensing electrodes on the base layer; attaching a conductive adhesive film on the pads and the ends of the base layer adjacent to the pads; cutting the ends of the conductive adhesive film and the base layer together; and bonding a circuit connection structure on the conductive adhesive film.

2. The method of 1 above, wherein the base layer includes a bonding area in which the pads are formed and a margin area adjacent to the bonding area in an extension direction of the pads,

The conductive adhesive film is attached together on the bonding region and the margin region, a method of manufacturing a touch sensor laminate.

3. The method of 2 above, wherein the step of cutting together the ends of the conductive adhesive film and the base layer comprises cutting a part of the conductive adhesive film attached on the margin region together with the base layer, touch sensor A method for manufacturing a laminate.

4. The method of 1 above, further comprising the step of forming an optical film on the touch sensor structure after the step of bonding the circuit connection structure on the conductive adhesive film, the manufacturing method of the touch sensor laminate.

5. The method of 4 above, wherein the optical film is formed to cover the front end of the circuit connection structure, the manufacturing method of the touch sensor laminate.

6. The method of 4 above, further comprising the step of cutting the optical film portion around the circuit connection structure together with the base layer after the step of forming the optical film, the manufacturing method of the touch sensor laminate.

7. The method of 4 above, wherein the optical film comprises a polarizing plate, the manufacturing method of the touch sensor laminate.

8. The method of 1 above, wherein the conductive adhesive film comprises an anisotropic conductive film (ACF), a method of manufacturing a touch sensor laminate.

9. A touch sensor structure including a base layer, sensing electrodes formed on the base layer, and pads connected to the sensing electrodes on the base layer;

a conductive adhesive film covering the pads and the ends of the base layer adjacent to the pads on the base layer together; and a circuit connection structure coupled on the conductive adhesive film,

Corner regions of the conductive adhesive film and the base layer adjacent to the circuit connection structure each include a convex portion, a touch sensor laminate.

10. The method of 9 above, wherein the convex portion comprises a first convex portion formed in a corner region of an upper portion of the conductive adhesive film and a second convex portion formed in a corner region of the bottom of the base layer, the touch sensor laminate.

11. The above 10, wherein the first convex portion does not protrude above the top surface of the conductive adhesive film, and the second convex portion does not protrude below the bottom surface of the base layer, the touch sensor laminate.

12. The above 9, further comprising an optical film laminated on the touch sensor structure and covering the front end of the circuit connection structure, the touch sensor laminate.

13. A touch sensor stack according to the above-described embodiments; and a window substrate disposed on the touch sensor laminate.

14. The method of 13 above, wherein the touch sensor laminate further comprises a polarizing plate laminated on the touch sensor structure, wherein the polarizing plate is disposed between the window substrate and the touch sensor structure, the window laminate.

15. Display panel; and a touch sensor laminate according to the above-described embodiments laminated on the display panel.

According to embodiments of the present invention, a conductive adhesive film covering a plurality of pads included in the touch sensor structure may be formed on a base layer, and the conductive adhesive film may be cut together with the base layer according to a predetermined size. . Accordingly, the conductive adhesive film and the substrate layer act as a mutual buffer structure to prevent defects such as resin separation, side cracks, and cracks. Accordingly, a bonding structure including a conductive adhesive film having a fine line width can be implemented with high reliability and high stability.

In some embodiments, side surfaces of the bonding part to which the conductive adhesive film and the base layer are adhered to each other may include a convex part. The convex part may function as a bending support part that buffers stress generated during bending of the flexible printed circuit board (FPCB).

1 to 7 are schematic plan and cross-sectional views for explaining a method of manufacturing a touch sensor laminate according to example embodiments.
8 is a partially enlarged plan view illustrating a touch sensor stack according to example embodiments.
9 is a schematic diagram illustrating a window laminate and an image display device according to example embodiments.

Embodiments of the present invention provide a touch sensor laminate including a bonding structure including a pad and a conductive adhesive film. In addition, embodiments of the present invention provide a method of manufacturing a touch sensor laminate including a bonding process and a cutting process.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is described in such drawings It should not be construed as being limited only to the matters.

1 to 7 are schematic plan and cross-sectional views for explaining a method of manufacturing a touch sensor laminate according to exemplary embodiments.

Referring to FIG. 1 , the touch sensor structure 100 may be prepared. The touch sensor structure 100 may include sensing electrodes 110 and 120 arranged on the base layer 105 .

The base layer 105 may include, for example, a transparent insulating material having flexibility. For example, the base layer 105 is a cyclic olefin polymer (COP), polyethylene terephthalate (PET), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyphenylene sulfide ( PPS), polyallylate, polyimide (PI), cellulose acetate propionate (CAP), polyethersulfone (PES), cellulose triacetate (TAC), polycarbonate (PC), cyclic olefin copolymer ( COC), polymethyl methacrylate (PMMA), and the like. The base layer 105 may include an inorganic insulating material such as glass or silicon oxide.

The base layer 105 may include an active area AA, a bonding area BA, and a margin area MA. The active area AA may include a central portion of the base layer 105 and may be an area in which a user's touch is substantially recognized and a signal is generated. For example, when a user's touch is input to the active area AA, a change in capacitance may occur by the sensing electrodes 110 and 120 . Accordingly, a physical touch may be converted into an electrical signal to realize touch sensing.

The sensing electrodes 110 and 120 may include first sensing electrodes 110 and second sensing electrodes 120 .

The first sensing electrodes 110 may be arranged, for example, in a longitudinal direction or a column direction (eg, first direction) of the base layer 105 or the touch sensor stack. Accordingly, the first sensing electrode column may be formed by the plurality of first sensing electrodes 110 . In addition, the plurality of first sensing electrode columns may be arranged in a width direction or a row direction (eg, a second direction).

In some embodiments, the first sensing electrodes 110 adjacent in the first direction may be physically or electrically connected to each other by the connection part 115 . For example, the connection part 115 may be integrally formed at the same level as the first sensing electrodes 110 .

The second sensing electrodes 120 may be arranged along the second direction. In some embodiments, the second sensing electrodes 120 may be physically spaced apart from each other as island-type unit electrodes. In this case, the second sensing electrodes 120 adjacent in the second direction may be electrically connected to each other by the bridge electrode 125 .

As the plurality of second sensing electrodes 120 are connected to each other by the bridge electrodes 125 and arranged in the second direction, a second sensing electrode row may be formed. In addition, a plurality of rows of the second sensing electrode may be arranged in the first direction.

The sensing electrodes 110 and 120 and the bridge electrode 125 are silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), and chromium (Cr), respectively. , titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn) , molybdenum (Mo), calcium (Ca), or an alloy thereof (eg, silver-palladium-copper (APC), copper-calcium (CuCa)). These may be used alone or in combination of two or more. For example, the sensing electrodes 110 and 120 may have a mesh structure including the metal or alloy.

The sensing electrodes 110 and 120 and the bridge electrode 125 are, respectively, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), and cadmium tin. A transparent conductive oxide such as oxide (CTO), a transparent conductive material such as silver nanowire (AgNW), carbon nanotube (CNT), graphene, a conductive polymer, or the like may be included.

In some embodiments, the sensing electrodes 110 and 120 may include a stacked structure of a transparent conductive oxide and a metal. For example, the sensing electrodes 110 and 120 may have a three-layer structure of a transparent conductive oxide layer, a metal layer, and a transparent conductive oxide layer. In this case, while the flexible characteristic is improved by the metal layer, the signal transmission speed may be improved by lowering the resistance, and corrosion resistance and transparency may be improved by the transparent conductive oxide layer.

In some embodiments, the bridge electrode 125 may be formed on an insulating layer (not shown). The insulating layer may at least partially cover the connection part 115 included in the first sensing electrode 110 , and may at least partially cover the second sensing electrodes 120 around the connection part 115 . The bridge electrode 125 may pass through the insulating layer and may be electrically connected to the second sensing electrodes 120 adjacent to each other with the connection part 115 interposed therebetween.

The insulating layer may include an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as an acrylic resin or a siloxane-based resin.

Traces 130 may branch and extend from each of the first sensing electrode columns and the second sensing electrode rows. The traces 130 may branch from the ends of each of the first sensing electrode column and the second sensing electrode row, and may extend on the peripheral area of the active area AA.

The traces 130 may extend toward the bonding area BA allocated to a part of one end of the touch sensor structure 100 or the base layer 105 in the longitudinal direction, for example. Distal ends of the traces 130 may be assembled on the bonding area BA of the base layer 105 . Pads 140 are formed on the bonding area BA, and may be respectively connected to the traces 130 . In one embodiment, the distal ends of traces 130 may be provided as pads 140 .

For convenience of description, a connection form of the traces 130 and the pads 140 is omitted in FIG. 1 .

In some embodiments, the touch sensor structure 100 may be formed through a transfer process. For example, the sensing electrode layer including the above-described sensing electrodes 110 and 120 , the bridge electrode 125 and the traces 130 may be formed on the carrier substrate. Thereafter, the sensing electrode layer is transferred to the base layer 105 and the carrier substrate is peeled off and removed to obtain the touch sensor structure 100 .

In an embodiment, a separation layer including an organic material for promoting a peeling process may be formed between the sensing electrode layer and the carrier substrate. The sensing electrode layer and the base layer 105 may be bonded to each other through an adhesive layer.

In some embodiments, a preliminary touch sensor structure in which a plurality of touch sensor structures 100 are assembled together may be manufactured first. Thereafter, the preliminary touch sensor structures may be cut according to product units, and the plurality of touch sensor structures 100 may be separated.

As shown in FIG. 1 , one end of the base layer 105 or the touch sensor structure 100 in the longitudinal direction may include a margin area MA adjacent to the bonding area BA. For example, the margin area MA may be an area extending from the bonding area BA where the pads 140 are disposed to one side of the base layer 105 .

2 and 3 , the conductive adhesive film 150 may be attached on the pads 140 .

In example embodiments, the conductive adhesive film 150 may at least partially cover each of the bonding area BA and the margin area MA. For example, the conductive adhesive film 150 commonly covers the plurality of pads 140 formed on the bonding area BA and additionally extends in the first direction (the extension direction of the pad 140 ). The pads 140 may cover the unformed end of the upper surface of the base layer 105 together.

For example, the conductive adhesive film 150 may include a resin layer and an anisotropic conductive film (ACF) including conductive particles dispersed in the resin layer.

Referring to FIG. 4 , for example, the ends of the base layer 105 and the conductive adhesive film 150 may be cut along the cutting line CL shown in FIG. 3 (eg, the first cutting process). ). Accordingly, portions of the base layer 105 and the conductive adhesive film 150 having a width corresponding to a portion of the margin area MA may be cut together and removed.

By the cutting process, the base layer 105 and the conductive adhesive film 150 may share substantially the same cut surface. Since the conductive adhesive film 150 is cut together with the base layer 105 to have a desired predetermined width, the cutting stress may be buffered or absorbed by the base layer 105 .

Therefore, it is possible to prevent defects such as resin leakage and damage to the cut surface that occur when the conductive adhesive film 150 is cut to a fine line width (eg, about 1 mm or less, about 0.5 mm or less, or about 0.4 mm or less).

In addition, since the base layer 105 is also cut together with the conductive adhesive film 150 , the stress transferred to the base layer 105 may also be buffered or reduced. Accordingly, defects such as cracks in the cut portion of the base layer 105 and the flow of the resin material included in the base layer 105 can be suppressed.

For convenience of explanation, although the shape of the cut surface is shown vertically in FIG. 4 , as will be described later with reference to FIG. 8 , the base layer 105 and the conductive adhesive film 150 may each include a convex part in the cut part.

Referring to FIG. 5 , the circuit connection structure 160 may be bonded on the conductive adhesive film 150 .

In example embodiments, the circuit connection structure 160 may include a flexible printed circuit board (FPCB). For example, the circuit connection structure 160 may include a core layer and circuit wiring formed on the core layer.

For example, the circuit connection structure 160 is aligned on the conductive adhesive film 150, and the circuit wiring of the circuit connection structure 160 and The pads 140 included in the bonding area BA may be electrically connected to each other.

Referring to FIG. 6 , an optical film 170 may be laminated on the touch sensor structure 100 .

According to exemplary embodiments, the optical film 170 may include a film or layer structure known in the art for improving image visibility of an image display device. Non-limiting examples of the optical film 170 may include a polarizing plate, a polarizer, a retardation film, a reflective sheet, a brightness enhancing film, a refractive index matching film, and the like. These may be included alone or as two or more multilayer structures.

In one embodiment, the optical film 170 may be a polarizing plate. In this case, the optical film 170 may include, for example, a polyvinyl alcohol-based polarizer and a protective film formed on at least one surface of the polarizer. The protective film may include, for example, a resin material such as triacetyl cellulose (TAC) or cyclic olefin polymer (COP).

In some embodiments, the optical film 170 may partially cover the bonding area BA, and may partially cover the front end of the circuit connection structure 160 . In addition, the optical film 170 may also contact the conductive adhesive film 150 .

By forming the optical film 170 to partially cover the bonding structure including the conductive adhesive film 150 and the circuit connection structure 160 , bonding stability may be further improved.

Referring to FIG. 7 , the optical film 170 and the periphery of the touch sensor structure 100 may be at least partially cut (eg, a second cutting process).

For example, the periphery of the optical film 170 and the touch sensor structure 100 (base layer 105) may be cut according to a predetermined product size. In some embodiments, as shown in FIG. 7 , the optical film 170 and the base layer 105 around the bonding structure may be partially cut and removed.

In this case, the optical film 170 may include a protrusion 172 covering the front end of the circuit connection structure 160 . For example, the protrusion 172 may correspond to a dummy area of the optical film 170 .

8 is a partially enlarged cross-sectional view illustrating a touch sensor laminate according to example embodiments. For example, FIG. 8 is a cross-sectional view showing in more detail the shape of the side or cut portion of the base layer 105 and the conductive adhesive film 150 around the above-described bonding structure.

Referring to FIG. 8 , as described with reference to FIG. 4 , ends of the conductive adhesive film 150 and the base layer 105 may be cut together. Cutting stress may be dispersed when the cutting tool comes into contact with the conductive adhesive film 150 and enters the above-described bonding structure.

Accordingly, the ends (or corner regions) of the conductive adhesive film 150 and the base layer 100 on one side adjacent to the bonding structure of the touch sensor structure 100 are convex portions 107 and 152 , respectively. may include.

According to exemplary embodiments, the corner region of the upper portion of the conductive adhesive film 150 includes the first convex portion 152 , and the corner region of the bottom of the base layer 105 includes the second convex portion 107 . can do.

The circuit connection structure 160 may be bent downward of the touch sensor structure 100 to be electrically connected to, for example, a driving integrated circuit (IC) chip disposed on the rear surface of the image display device. Each of the first convex portion 152 and the second convex portion 107 may function as a buffer structure to prevent abrupt bending of the circuit connection structure 160 . Accordingly, it is possible to suppress or reduce defects such as cracks and fractures due to bending stress of the core layer and circuit wires included in the circuit connection structure 160 .

The first and second convex portions 152 and 107 may function as a bending support portion or a bending guide portion for bending the circuit connection structure 160 .

In some embodiments, the first convex portion 152 may not protrude above the top surface of the conductive adhesive film 150 . The second convex portion 107 may not protrude below the bottom surface of the base layer 105 . Accordingly, it is possible to prevent a step difference without deteriorating the overall flatness of the touch sensor structure 100 and to improve the bending stability of the circuit connection structure 160 .

9 is a schematic diagram illustrating a window laminate and an image display apparatus according to exemplary embodiments.

Referring to FIG. 9 , the window stack 200 may include the window substrate 250 and the touch sensor stack 220 according to the above-described exemplary embodiments.

The window substrate 250 includes, for example, a hard coating film, a thin glass (eg, ultra-thin glass (UTG)), and the like, and in one embodiment, a periphery of one surface of the window substrate 250 . A light blocking pattern 240 may be formed on the light blocking pattern 240. The light blocking pattern 240 may include, for example, a color printing pattern, and may have a single-layer or multi-layer structure.

A bezel part or a non-display area of the image display device may be defined by the light blocking pattern 240 . The light blocking pattern 240 may be provided as a deco film or a deco pattern.

The touch sensor laminate 220 according to the above-described exemplary embodiments may be coupled to the window substrate 250 in the form of a film or a panel. In an embodiment, the touch sensor stack 220 may be coupled to the window substrate 250 through the first adhesive layer 230 .

For example, the window substrate 250 , the optical film 170 of the touch sensor stack 220 , and the touch sensor structure 100 of the touch sensor stack 220 may be disposed in order from the user's viewing side. In this case, since the sensing electrodes of the touch sensor stack 220 are disposed under the optical film 170 including a polarizer or a polarizing plate, it is possible to more effectively prevent a pattern recognition phenomenon.

The image display device may include the above-described window stack 200 including the display panel 300 and the display panel 300 and coupled on the display panel 300, including the touch sensor stack 220 according to exemplary embodiments. have.

The display panel 300 may include a pixel electrode 310 , a pixel defining layer 320 , a display layer 330 , a counter electrode 340 , and an encapsulation layer 350 disposed on a panel substrate 305 . can

The panel substrate 305 may include a flexible resin material, and in this case, the image display device may be provided as a flexible display.

A pixel circuit including a thin film transistor (TFT) may be formed on the panel substrate 305 , and an insulating layer covering the pixel circuit may be formed. The pixel electrode 310 may be electrically connected to, for example, a drain electrode of a TFT on the insulating layer.

The pixel defining layer 320 may be formed on the insulating layer to expose the pixel electrode 310 to define a pixel area. A display layer 330 is formed on the pixel electrode 310 , and the display layer 330 may include, for example, a liquid crystal layer or an organic light emitting layer.

A counter electrode 340 may be disposed on the pixel defining layer 320 and the display layer 330 . The opposite electrode 340 may be provided, for example, as a common electrode or a cathode of the image display device. An encapsulation layer 350 for protecting the display panel 300 may be stacked on the opposite electrode 340 .

The display panel 300 may be coupled to the touch sensor stack 220 through the second adhesive layer 210 . For example, the thickness of the second adhesive layer 210 may be greater than the thickness of the first adhesive layer 230 , and the viscoelasticity at -20 to 80° C. may be about 0.2 MPa or less. In this case, noise from the display panel 300 may be shielded, and interfacial stress may be relieved during bending to suppress damage to the window laminate 200 . In one embodiment, the viscoelasticity may be about 0.01 to 0.15 MPa.

100: touch sensor structure 105: base layer
110: first sensing electrode 115: connection part
120: second sensing electrode 125: bridge electrode
130: trace 140: pad
150: conductive adhesive film 160: circuit connection structure
170: optical film

Claims (15)

preparing a touch sensor structure including a base layer, sensing electrodes formed on the base layer, and pads connected to the sensing electrodes on the base layer;
attaching a conductive adhesive film on the pads and the ends of the base layer adjacent to the pads;
cutting the ends of the conductive adhesive film and the base layer together; and
Comprising the step of bonding a circuit connection structure on the conductive adhesive film, the manufacturing method of the touch sensor laminate. The method according to claim 1, wherein the base layer comprises a bonding area in which the pads are formed and a margin area adjacent to the bonding area in an extension direction of the pads,
The conductive adhesive film is attached together on the bonding region and the margin region, a method of manufacturing a touch sensor laminate. The method according to claim 2, wherein the step of cutting together the ends of the conductive adhesive film and the base layer comprises cutting a part of the conductive adhesive film attached on the margin region together with the base layer, the touch sensor laminate manufacturing method. The method according to claim 1, further comprising the step of forming an optical film on the touch sensor structure after bonding the circuit connection structure on the conductive adhesive film, the manufacturing method of the touch sensor laminate. The method of claim 4, wherein the optical film is formed to cover the front end of the circuit connection structure. The method according to claim 4, further comprising the step of cutting the optical film portion around the circuit connection structure with the base layer after the step of forming the optical film, the manufacturing method of the touch sensor laminate. The method according to claim 4, wherein the optical film comprises a polarizing plate, the manufacturing method of the touch sensor laminate. The method according to claim 1, wherein the conductive adhesive film comprises an anisotropic conductive film (ACF), the manufacturing method of the touch sensor laminate. a touch sensor structure including a base layer, sensing electrodes formed on the base layer, and pads connected to the sensing electrodes on the base layer;
a conductive adhesive film covering the pads and the ends of the base layer adjacent to the pads on the base layer together; and
A circuit connection structure coupled on the conductive adhesive film,
Corner regions of the conductive adhesive film and the base layer adjacent to the circuit connection structure each include a convex portion, a touch sensor laminate. The method according to claim 9, wherein the convex portion comprises a first convex portion formed in an upper corner region of the conductive adhesive film and a second convex portion formed in a corner region of the bottom of the base layer, the touch sensor laminate. The method according to claim 10, The first convex portion does not protrude above the upper surface of the conductive adhesive film, the second convex portion does not protrude below the bottom surface of the base layer, the touch sensor laminate. The method according to claim 9, laminated on the touch sensor structure and further comprising an optical film covering the front end of the circuit connection structure, the touch sensor laminate. The touch sensor laminate of claim 9; and
A window laminate comprising a window substrate disposed on the touch sensor laminate. The method according to claim 13, wherein the touch sensor laminate further comprises a polarizing plate laminated on the touch sensor structure,
The polarizing plate is disposed between the window substrate and the touch sensor structure, a window laminate. display panel; and
An image display device comprising the touch sensor laminate of claim 9 laminated on the display panel.

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