WO2020204434A1

WO2020204434A1 - Flexible display module and image display device including same

Info

Publication number: WO2020204434A1
Application number: PCT/KR2020/003993
Authority: WO
Inventors: 이진우; 손동진; 윤주인
Original assignee: 동우화인켐 주식회사
Priority date: 2019-03-29
Filing date: 2020-03-24
Publication date: 2020-10-08
Also published as: KR20200114765A

Abstract

A flexible display module according to embodiments of the present invention comprises: a display panel; a touch sensor layer arranged on the display panel; a flexible printed circuit board electrically connected to traces at one end of the touch sensor layer; and a support structure for covering both of or a portion of the flexible printed circuit board and the touch sensor layer. The touch sensor layer includes sensing electrodes and traces which are branched from the sensing electrodes and which include at least one from among a silver nanowire, graphene or carbon nanotube. End parts of the display panel and the touch sensor layer are bent together with the support structure.

Description

Flexible display module and image display device including the same

The present invention relates to a flexible display module and an image display device including the same. More specifically, it relates to a flexible display module to which a touch sensor is coupled and an image display device including the same.

With the recent development of information technology, demands for the display field have been suggested in various forms. For example, various flat panel display devices with features such as thinner, lighter, and low power consumption, for example, a liquid crystal display device, a plasma display panel device, Research is being conducted on an electroluminescent display device and an organic light-emitting diode display device.

On the other hand, a touch panel or a touch sensor, which is an input device that is attached on the display device and allows the user's command to be input by selecting the instruction content displayed on the screen as a human hand or object, is combined with the display device to provide an image display function and Electronic devices with an information input function are being developed.

In addition, recently, a flexible display having flexibility that can be folded or bent has been developed, and accordingly, the touch sensor needs to be developed to have appropriate physical properties, design, and structure to be applied to a flexible display.

For example, when the touch sensor is bent or folded, damage such as peeling or cracking of wires included in the touch sensor may be caused. In addition, when the touch sensor is bent to connect the touch sensor to the circuit, the degree of bending may be increased to increase the display area area. In this case, mechanical damage to the wiring may be intensified.

For example, as in Korean Patent Publication No. 2014-0092366, a touch sensor or a touch screen panel coupled to various image display devices has been recently developed.

An object of the present invention is to provide a flexible display module having improved electrical and mechanical reliability and flexibility.

An object of the present invention is to provide an image display device including a flexible display module having improved electrical and mechanical reliability and flexibility.

1. Display panel; A touch sensor layer disposed on the display panel and including sensing electrodes and traces branching from the sensing electrodes and including at least one of silver nanowires, graphene, and carbon nanotubes; A flexible circuit board electrically connected to the traces at one end of the touch sensor layer; And a support structure that commonly and partially covers the flexible circuit board and the touch sensor layer, wherein ends of the display panel and the touch sensor layer are bent together with the support structure.

2. The flexible display module according to the above 1, wherein the trace comprises silver nanowires, and optionally further comprises graphene or carbon nanotubes.

3. In 1 above, the sensing electrode and the trace each include a metal layer or a transparent conductive oxide layer,

The traces are formed on the metal layer or the transparent conductive oxide layer, and include a conductive capping layer including at least one of silver nanowires, graphene, and carbon nanotubes.

4. The flexible display module according to the above 3, wherein the sensing electrode and the trace each include a stacked structure of the metal layer and the transparent conductive oxide layer.

5. The flexible display module according to 3 above, wherein the conductive capping layer entirely covers the top and sidewalls of the trace.

6. The flexible display module according to the above 1, further comprising an optical layer covering the sensing electrodes of the touch sensor layer.

7. The flexible display module according to the above 6, wherein a gap is formed between the optical layer and the support structure.

8. The flexible display module according to the above 7, further comprising a filling layer at least partially filling the gap.

9. The flexible display module according to the above 8, wherein the filling layer includes an adhesive resin.

10. The flexible display module according to the above 6, wherein the ends of the display panel and the touch sensor layer are bent so that the flexible circuit board faces the optical layer.

11. The flexible display module according to the above 10, further comprising a fixing structure inserted between portions of the display panel overlapping with the optical layer and the flexible circuit board facing each other.

12. The flexible display module according to the above 6, wherein the optical layer includes at least one selected from the group consisting of a polarizer, a polarizing plate, a retardation film, a reflective sheet, a brightness enhancing film, and a refractive index matching film.

13. The flexible display module according to the above 1, further comprising a bonding layer bonding the display panel and the touch sensor layer.

14. The flexible display module according to the above 1, wherein the curvature of the curved portion of the display panel and the touch sensor layer is 0.05R to 0.5R with respect to a radius of curvature R.

15. The flexible display module according to the above 1, wherein the display panel includes an organic light emitting diode (OLED) panel.

16. Flexible display module according to the above-described embodiments; And a window substrate disposed on the flexible display module.

17. The image display device according to the above 16, further comprising a main board disposed under the flexible display module, wherein the flexible circuit board of the flexible display module is electrically connected to the main board.

In the flexible display module according to the embodiments of the present invention, the display panel and the touch sensor layer may be integrated through the bonding layer. The touch sensor layer may be made of, for example, a thin film of a substrate-less type, and may be combined with the display panel. Accordingly, by bending the display panel and the touch sensor layer together, the area of the bezel part or the light blocking part may be reduced, and the size of the display area may be expanded.

The traces of the touch sensor layer include silver nanowires, carbon nanotubes, or graphene, and may have higher flexibility than sensing electrodes. Therefore, even if bending and bending are performed at the ends of the touch sensor layer, the traces are cracked and broken. Can be suppressed or reduced. In addition, the transmittance of the traces increases, so that the bezel area of the display device may be reduced.

In some embodiments, the display module may include a support structure partially covering the touch sensor layer and the flexible printed circuit board together. When the flexible display module is folded or bent by the support structure, peeling of the flexible printed circuit board may be prevented, and damage to sensing electrodes or traces in the bending area may be additionally prevented. In addition, even if it is bent with a radius of curvature of about 0.5R or less, for example, it is possible to implement a highly reliable circuit connection without interlayer separation.

1 and 2 are cross-sectional views illustrating a schematic structure of a flexible display module according to exemplary embodiments, respectively.

3 and 4 are schematic plan and cross-sectional views respectively illustrating a structure of a touch sensor layer according to exemplary embodiments.

5 is a schematic cross-sectional view illustrating a structure of a touch sensor layer according to some exemplary embodiments.

6 is a schematic plan view illustrating a structure of a touch sensor layer according to some exemplary embodiments.

7 is a cross-sectional view illustrating a schematic structure of a flexible display module according to some exemplary embodiments.

8 is a schematic cross-sectional view illustrating an image display device including a flexible display module according to example embodiments.

Embodiments of the present invention include a display panel and a touch sensor layer integrated with each other by a bonding layer, a flexible circuit board connected to one end of the touch sensor layer, and a support partially covering the touch sensor layer and the flexible circuit board together. It provides a flexible display module comprising a structure, the display panel and the touch sensor layer are bent together.

In addition, embodiments of the present invention provide an image display device including the flexible display module.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the present invention, so the present invention is described in such drawings. It is limited to matters and should not be interpreted.

In the following drawings, for example, two directions that are parallel to the upper surface of the display panel or the touch sensor layer and cross each other perpendicularly are defined as a first direction and a second direction. For example, the first direction may correspond to a length direction of the flexible display module, and the second direction may correspond to a width direction of the flexible display module. In addition, a direction perpendicular to the first and second directions is defined as a third direction. For example, the third direction may correspond to a thickness direction of the flexible display module.

1 and 2 are cross-sectional views illustrating a schematic structure of a flexible display module according to exemplary embodiments.

Referring to FIG. 1, the flexible display module includes a display panel 100, a bonding layer 110 and a touch sensor layer 120, and is connected to one end of the touch sensor layer 120. ) And a support structure 150 that partially covers the flexible circuit board 140 and the touch sensor layer 120 together.

The display panel 100 may include, for example, a liquid crystal display (LCD) panel or an organic light emitting diode display (OLED) panel. Preferably, the display panel 100 may comprise an OLED panel. In the case of the OLED panel, since a back-plane structure such as a backlight unit may be omitted, bending or bending together with the touch sensor layer 120 is easily implemented as described with reference to FIG. 2. Can be.

The structure and configuration of the display panel 100 will be described later in more detail with reference to FIG. 8.

The bonding layer 110 may be formed on the upper surface of the display panel 100. For example, the bonding layer 110 may be formed on the upper encapsulation layer of the display panel 100.

In example embodiments, the bonding layer 110 may include a pressure-sensitive adhesive (PSA) or an optically transparent adhesive (OCA) including an acrylic resin.

A touch sensor layer 120 may be stacked on the bonding layer 110. The touch sensor layer 120 may be coupled to the display panel 100 through the bonding layer 110. Accordingly, the display panel 100 and the touch sensor layer 120 may be integrated into one module.

The touch sensor layer 120 may include a sensing electrode, conductive patterns such as the trace extending from the sensing electrode, and may further include an insulating layer for mutual insulation of the conductive patterns. The configuration and structure of the touch sensor layer 120 will be described later in more detail with reference to FIGS. 3 to 6.

According to exemplary embodiments, the touch sensor layer 120 may be manufactured in a substantially inorganic material (substrate-less) type. For example, an intermediate layer may be formed on a carrier substrate, and the sensing electrode and trace may be formed on the intermediate layer. Thereafter, after the carrier substrate is removed from the intermediate layer, it may be directly attached to the display panel 100 through the bonding layer 110.

The intermediate layer may include a polymer organic layer capable of promoting peeling from the carrier substrate. As a non-limiting example, the intermediate layer is a polyimide-based polymer, a polyvinyl alcohol-based polymer, a polyamic acid-based polymer, a polyamide-based polymer, and a polyethylene-based polymer. Polymer, polystylene polymer, polynorbornene polymer, phenylmaleimide copolymer polymer, polyazobenzene polymer, polyphenylenephthalamide polymer, poly Ester polymer, polymethyl methacrylate polymer, polyarylate polymer, cinnamate polymer, coumarin polymer, phthalimidine polymer A polymer material such as a polymer, a chalcone-based polymer, and an aromatic acetylene-based polymer may be included. These may be used alone or in combination of two or more.

A flexible printed circuit board (FPCB) 140 is disposed on one end of the touch sensor layer 120 and may be electrically connected to the traces included in the touch sensor layer 120. In one embodiment, a terminal portion or a pad portion formed at an end of the trace and a circuit wiring included in the flexible circuit board 140 are formed by a conductive intermediate structure such as an anisotropic conductive film (ACF). They can be electrically connected to each other.

The flexible circuit board 140 may include, for example, a core layer including a resin or a liquid crystal polymer, and the circuit wiring printed on the core layer. In addition, the flexible circuit board 140 may further include a coverlay layer covering the circuit wiring on the core layer. A portion of the coverlay layer may be removed to expose a portion of the circuit wiring connected to the terminal portion or the pad portion of the touch sensor layer 120.

The touch sensor layer 120 may further include a passivation layer protecting the sensing electrode and traces. In this case, a portion of the passivation layer formed in a connection area to which the traces of the flexible circuit board 140 and the touch sensor layer 120 are connected may be removed.

The support structure 150 may be formed on a portion of the flexible circuit board 140 disposed on the connection area and a portion of the touch sensor layer 120. Accordingly, the support structure 150 may cover the ends of the touch sensor layer 120 and the flexible circuit board 140 in common and partially.

The support structure 150 suppresses peeling of the flexible circuit board 140 caused by external stress in the connection area, and prevents damage such as peeling or cracking of the sensing electrode or trace occurring during a folding or bending operation. It can be provided as a protective pattern.

The support structure 150 may have a multilayer structure. For example, the support structure 150 may include a base layer 152 and a support layer 154 formed on the surface of the base layer 152. The support layer 154 includes, for example, an acrylic-based, silicone-based, urethane-based, and/or rubber-based point-adhesive material, and ends of the flexible circuit board 140 and the touch sensor layer 120 in the connection area You can hold and contact with them.

The base layer 152 may include, for example, a polymer film. For example, the polymer film 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 flexible display module may further include an optical layer 130. The optical layer 130 may include a film or a layer structure known in the art for improving image visibility implemented from a pixel portion of the display panel 100. Non-limiting examples of the optical layer 130 include a polarizing plate, a polarizer, a retardation film, a reflective sheet, a brightness enhancement film, and a refractive index matching film. These may be included alone or in a multilayer structure of two or more.

According to example embodiments, the optical layer 130 may substantially overlap the display area of the display panel 100 or the touch sensor layer 120. The optical layer 130 may be located on the same layer or at the same level as the support structure 150.

In some embodiments, an adhesive layer for bonding the optical layer 130 may be further formed on the upper surface of the touch sensor layer 120.

Referring to FIG. 2, an end (eg, an end in the first direction) of the flexible display module to which the flexible circuit board 140 is coupled may be bent and disposed under the optical layer 130.

As shown in FIG. 2, ends of the display panel 100 and the touch sensor layer 120 that do not overlap with the optical layer 130 may be integrated by the bonding layer 110 and bent together. The ends may be bent in the third direction and extend again in the first direction to face the optical layer 130 in the third direction. Accordingly, the flexible circuit board 140 may be electrically connected to the main board 160 disposed under the display panel 100 under the optical layer 130.

For example, the flexible circuit board 140 and the driving circuit included in the main board 160 may be connected through the bonding pads 165 formed on the bottom of the main board 160. Accordingly, the driving circuit and the trace included in the touch sensor layer 120 are electrically connected to each other so that the touch sensing signal/driving signal may be mutually transmitted.

According to exemplary embodiments, the support structure 150 may be bent together with the curved ends of the display panel 100 and the touch sensor layer 120. Accordingly, peeling of the touch sensor layer 120 due to flexural stress and damage to electrodes and wirings can be prevented. Also, while bending is performed, the flexible circuit board 140 may be fixed by the support structure 150. Accordingly, the connection between the flexible circuit board 140 and the traces of the touch sensor layer 120 in the connection area can be stably maintained.

In addition, since the bonding layer 110 is continuously formed between the curved ends of the display panel 100 and the touch sensor layer 120 and bent together, the display panel 100 and the touch sensor layer 120 are integrated. Bending can be implemented.

In some embodiments, the curvature of the curved area or the curved portion of the display panel 100 and the touch sensor layer 120 may be about 0.05R to 0.5R (R refers to a radius of curvature). Even when a sharp curvature of about 0.5R or less is applied, delamination and mechanical damage of the touch sensor layer 120 and the display panel 100 may be prevented by the support structure 150 and the bonding layer 110.

In some embodiments, the thickness of the bonding layer 110 may be greater than the thickness of each of the touch sensor layer 120 and the display panel 100 to secure bending reliability. In addition, the thickness of the support structure 150 may also be greater than the thickness of each of the touch sensor layer 120 and the display panel 100.

In one embodiment, the thickness of the touch sensor layer 120 may be smaller than the thickness of each of the display panel 100 and the optical layer 130. Accordingly, bending having a curvature in the above-described range can be easily implemented. As described above, the touch sensor layer 120 may be included as an inorganic material type thin film.

In some embodiments, the fixing structure 155 may be disposed between the curved end of the display panel 100 and the uncurved portion of the display panel 100 under the optical layer 130.

The fixing structure 155 includes, for example, a PSA-based, OCA-based, or rubber-based point-adhesive material, and is bent to fix portions of the display panel 100 facing each other, thereby maintaining bending reliability.

3 and 4 are schematic plan and cross-sectional views respectively illustrating a structure of a touch sensor layer according to exemplary embodiments. 4 shows the cross-section of the trace 80 and the arrangement of the

sensing electrodes

60 and 70 around the bridge electrode 75 together.

3 and 4, the touch sensor layer 120 may include sensing

electrodes

60 and 70 and traces 80. According to exemplary embodiments, the

sensing electrodes

60 and 70 may be arranged to be driven by a mutual capacitance method.

The

sensing electrodes

60 and 70 and the traces 80 may be arranged on the intermediate layer 50. As described above, the intermediate layer 50 is included for peeling from the carrier substrate, for example, and may include an organic polymer material.

The touch sensor layer 120 may include an active area A and a trace area T. The active area A may be an area in which a user's touch can be input and sensed by the

sensing electrodes

60 and 70. Traces 80 branching from the

sensing electrodes

60 and 70 are disposed in the trace area T, and a part of the trace area T is a connection area for electrical connection with the flexible circuit board 140. Can be provided.

The active area A may include the display area D. For example, the display area D may correspond to the center of the active area A. The display area D may be an area in which an image of the image display device is implemented by a user. According to example embodiments, an area where the optical layer 130 shown in FIG. 1 overlaps may correspond to the display area D.

The

sensing electrodes

60 and 70 may be arranged in the active area A of the touch sensor layer. According to example embodiments, the

sensing electrodes

60 and 70 may include first sensing electrodes 60 and second sensing electrodes 70.

The first sensing electrodes 60 may be arranged along the second direction (eg, the width direction), for example. Accordingly, a row of first sensing electrodes extending in the second direction may be formed by the plurality of first sensing electrodes 60. Also, a plurality of rows of the first sensing electrodes may be arranged along the first direction.

In some embodiments, the first sensing electrodes 60 adjacent to each other in the second direction may be physically or electrically connected to each other by the connection part 65. For example, the connection part 65 may be integrally formed at the same level as the first sensing electrodes 60.

The second sensing electrodes 70 may be arranged along the first direction (eg, a length direction). In some embodiments, the second sensing electrodes 70 may be physically spaced apart from each other as island-type unit electrodes. In this case, the second sensing electrodes 70 adjacent in the first direction may be electrically connected to each other by the bridge electrode 75.

As the plurality of second sensing electrodes 70 are connected to each other by the bridge electrodes 75 and arranged in the first direction, a second sensing electrode row extending in the first direction may be formed. Further, a plurality of the second sensing electrode rows may be arranged along the second direction.

The

sensing electrodes

60 and 70 and/or the bridge electrode 75 may include a metal, an alloy, or a transparent conductive oxide.

For example, the

sensing electrodes

60 and 70 and/or the bridge electrode 75 are silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd) , Chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni) , Zinc (Zn), tin (Sn), molybdenum (Mo). Calcium (Ca) or an alloy thereof (eg, silver-palladium-copper (APC)) may be included. These may be used alone or in combination of two or more.

The

sensing electrodes

60 and 70 and/or the bridge electrode 75 are, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium A transparent conductive oxide such as tin oxide (CTO) may be included.

In some embodiments, the

sensing electrodes

60 and 70 and/or the bridge electrode 75 may include a stacked structure of a transparent conductive oxide and a metal. For example, the

sensing electrodes

60 and 70 and/or the bridge electrode 75 may have a three-layer structure of a transparent conductive oxide layer-metal layer-transparent conductive oxide layer. In this case, while the flexible property is improved by the metal layer, a signal transmission speed may be improved by lowering resistance, and corrosion resistance and transparency may be improved by the transparent conductive oxide layer.

In some embodiments, the bridge electrode 75 may be formed on the insulating layer 55. The insulating layer 55 may at least partially cover the connection portions 65 included in the first sensing electrode row and at least partially cover the second sensing electrodes 70 around the connection portion 65. The bridge electrode 75 penetrates the insulating layer and may be electrically connected to the second sensing electrodes 70 adjacent to each other with the connection part 65 therebetween.

The insulating layer 55 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 resin.

Traces 80 may extend from each of the first sensing electrode row and the second sensing electrode column.

As shown in FIG. 3, the traces 80 may extend from the active area A or the periphery of the display area D to be aggregated into the trace area T.

For example, the traces 80 may be branched from each first sensing electrode row from both sides of the touch sensor layer and extend in the first direction. Thereafter, the traces 80 may be bent while entering the trace area T to extend in the second direction. The traces 80 may be bent again in the first direction and may extend to the connection area.

In some embodiments, the traces 80 extending from the first sensing electrode row may be alternately distributed on both sides of the touch sensor layer 120. Since the traces 80 are evenly distributed on both sides of the touch sensor layer 120, stress generated when bending or bending is applied can be uniformly distributed. In addition, since the traces 80 are alternately disposed on both sides, an alignment margin between neighboring traces 80 can be increased.

Also, the traces 80 may be branched from each second sensing electrode row and may extend in the second direction within the trace area T. Thereafter, it is bent again in the first direction to extend to the connection area in the first direction.

The distal ends of the traces 80 may be aggregated within the connection area and provided as a connection part 85 electrically connected to the flexible circuit board 140. A connection portion 85 is defined from each of the traces 80 and may be disposed within the connection area.

The traces 80 may include a conductive material having improved flexibility. According to exemplary embodiments, the traces 80 may include at least one of silver nanowires, graphene, and carbon nanotubes. Preferably, the traces 80 may include silver nanowires. In one embodiment, the traces 80 include silver nanowires, and may optionally further include carbon nanotubes or graphene.

According to example embodiments, the flexible circuit board 140 may be electrically connected to the connection parts 85 on the connection area. In some embodiments, a conductive intermediate structure such as an anisotropic conductive film (ACF) may be disposed between the flexible circuit board 140 and the connection parts 85.

The support structure 150 shown in FIGS. 1 and 2 may cover the trace area T in the planar direction, and may cover a part of the active area A. According to example embodiments, a portion of the active area A between the display area D and the trace area T may be covered together by the support structure 150.

The active area A part covered by the support structure 150 (for example, the active area A part not covered by the optical layer 130) is as shown in FIG. 2 together with the trace area T. Can be bent together.

The area of the bezel part visible to the user may be reduced by bending the active area A portion substantially provided as the bezel part or the non-display area together with the display panel 100. Accordingly, even when the total area of the image display device is reduced, the display area D can be expanded.

As shown in FIG. 4, in some embodiments, the

sensing electrodes

60 and 70 may include a stacked structure of a transparent conductive oxide layer and a metal layer. In an embodiment, the first sensing electrode 60 and the second sensing electrode 70 are each of the first transparent conductive oxide layers 62 and 72 sequentially stacked from the upper surface of the intermediate layer 50, and the metal layers 64 and 74. ) And second transparent conductive oxide layers 66 and 76.

In some embodiments, the trace 80 may also include a sequentially stacked structure of the first transparent conductive oxide layer 72, the metal layer 84, and the second transparent conductive oxide layer 86. According to exemplary embodiments, the trace 80 may further include a conductive capping layer 88 including silver nanowires, graphene and/or carbon nanotubes.

For example, the conductive capping layer 88 is after spinning or coating a solution-type composition containing silver nanowires, graphene and/or carbon nanotubes, and then the conductive capping layer 88 is selectively formed on the trace 80. It may be formed by etching to remain.

4, the conductive capping layer 88 may be formed on the upper surface of the second transparent conductive oxide layer 86.

In some embodiments, the bridge electrode 75 may include the aforementioned metal or alloy to reduce channel resistance.

In FIG. 4, the trace 80 is shown to include a conductive capping layer 88 including silver nanowire, graphene and/or carbon nanotube, but the trace 80 is silver nanowire, graphene and/or carbon nanotube. It may have a single layer structure including a tube. In this case, flexibility and bending characteristics through the trace area T may be further improved.

Referring to FIG. 5, the conductive capping layer 89 may substantially entirely cover the upper surface and sidewalls of the trace 80. Accordingly, signal resistance through the trace 80 may be further reduced, and transmittance may be improved.

According to the above-described exemplary embodiments, conductive capping layers 88 and 89 including silver nanowires, graphene, and/or carbon nanotubes may be selectively formed on the trace 80. As silver nanowires, graphene, and/or carbon nanotubes having lower resistance than transparent conductive oxides and excellent in flexibility are applied on the traces 80, when bending or bending is applied in the trace area T, the traces 80 ) To prevent mechanical damage such as cracking and fracture.

In addition, the transmittance of the trace 80 may be improved by applying silver nanowires, graphene and/or carbon nanotubes having higher transmittance than transparent conductive oxides such as metal or ITO. Accordingly, even if the traces 80 are included in the display area D, a decrease in transmittance can be prevented, and accordingly, the area of the bezel area of the display module can be reduced.

Referring to FIG. 6, sensing electrodes 67 and traces 87 of the touch sensor layer 120 may be arranged to be driven in a self-capacitance method.

The touch sensor layer 120 may include sensing electrodes 67 each provided in an independent island pattern. Further, the traces 87 may be branched to each sensing electrode 67 and may extend to the trace area T. The distal ends of the traces 87 may be aggregated in a connection area disposed at one end of the trace area T to be electrically connected to the flexible circuit board 140.

The traces 87 may include silver nanowires, graphene, and/or carbon nanotubes, as described with reference to FIG. 5. In some embodiments, the traces 87 may include conductive capping layers 88 and 89 including silver nanowires, graphene and/or carbon nanotubes.

As described above, the support structure 150 may cover a portion of the trace area T and the active area A and support the touch sensor layer 120 and the flexible circuit board 140 together. Further, the curvature starts from the active area A excluding the display area D, and after the curvature, the trace area T may be disposed to substantially face the display area D.

7 is a cross-sectional view illustrating a schematic structure of a flexible display module according to some exemplary embodiments. Detailed descriptions of structures and configurations that are substantially the same as or similar to those described with reference to FIG. 1 are omitted.

Referring to FIG. 7, the optical layer 130 and the support structure 150 may be spaced apart by a predetermined distance in the first direction to form a gap 155. The gap 155 may be provided as a margin area for alignment of the support structure 150.

According to example embodiments, a filiing layer 165 filling the gap 155 may be formed. The filling layer 165 at least partially fills the gap 155 and may contact the upper surface of the touch sensor layer 120 and sidewalls of the optical layer 130 and the support structure 150.

In some embodiments, the filling layer 165 may be formed to have an upper surface lower than the upper surface of each of the optical layer 130 and the support structure 150.

The peeling layer 165 may be formed by filling the adhesive resin composition in the gap 155 and then curing through room temperature curing, thermal curing, or ultraviolet curing process. The resin composition may include acrylic, silicone, urethane, and/or rubber based resins. In one embodiment, the resin composition may further include a solvent, a photopolymerizable monomer, a polymerization initiator, and a curing agent.

As described above, during the attaching process of the support structure 150, an alignment margin may be first secured through the gap 155 to prevent contact with the optical layer 150. Thereafter, the filling layer 165 may be formed by separately filling the resin composition to fill the gap 155. Accordingly, the exposed area of the touch sensor layer 120 is reduced by the filling layer 165, so that the protective effect of the sensing electrode may be further improved. In addition, as the peeling layer 165 contacts and holds the sidewalls of the optical layer 130 and the support structure 150, the optical layer 130, the support structure 150, and the traces 80 are peeled off when bending is applied. In addition, the occurrence of cracks can be further reduced.

The image display device may be a flexible display device, and may include a window substrate 180 and the aforementioned flexible display module.

As described above, the flexible display module may include a display panel 100 and a touch sensor layer 120 integrated with each other by the bonding layer 110. The optical layer 130 may be stacked on the display area D of the touch sensor layer 120. In FIG. 8, illustration of the support structure 150 and the flexible circuit board 140 is omitted for convenience of description.

The window substrate 180 includes, for example, a thin glass (for example, Ultra-Thin Glass (UTG)) hard coating film, and in one embodiment, light shielding on the periphery of one surface of the window substrate 180 The pattern 185 may be formed. The light blocking pattern 185 may include, for example, a color printing pattern, and may have a single layer or a multilayer structure. A bezel part or a non-display area of the image display device may be defined by the light blocking pattern 185.

The optical layer 130 may include various optical films or optical structures included in the image display device, and in some embodiments may include a coated polarizer or a polarizing plate. The coating polarizer may include a liquid crystal coating layer including a polymerizable liquid crystal compound and a dichroic dye. In this case, the optical layer 130 may further include an alignment layer for imparting alignment to the liquid crystal coating layer.

For example, the polarizing plate may include a polyvinyl alcohol-based polarizer and a protective film attached to at least one surface of the polyvinyl alcohol-based polarizer.

The optical layer 130 may be directly bonded to the one surface of the window substrate 180 or may be attached through the second point-adhesive layer 114. In one embodiment, the optical layer 130 may be coupled to the touch sensor layer 120 through the first adhesive layer 112.

As shown in FIG. 8, the window substrate 180, the optical layer 130, and the touch sensor layer 120 may be arranged in order from the user's viewing side. In this case, since the sensing electrodes of the touch sensor layer 120 are disposed under the optical layer 130 including a polarizer or a polarizing plate, the electrode visibility phenomenon can be more effectively prevented.

The display panel 100 may include a pixel electrode 210, a pixel defining layer 220, a display layer 230, a counter electrode 240, and an encapsulation layer 250 disposed on the panel substrate 205. I can.

The panel substrate 205 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 205, and an insulating layer may be formed to cover the pixel circuit. The pixel electrode 210 may be electrically connected to, for example, a drain electrode of a TFT on the insulating layer.

The pixel defining layer 220 may be formed on the insulating layer to expose the pixel electrode 210 to define a pixel region. A display layer 230 is formed on the pixel electrode 210, and the display layer 230 may include, for example, a liquid crystal layer or an organic emission layer.

The counter electrode 240 may be disposed on the pixel defining layer 220 and the display layer 230. The counter electrode 240 may be provided as, for example, a common electrode or a cathode of an image display device. An encapsulation layer 250 for protecting the display panel 200 may be stacked on the counter electrode 240.

Hereinafter, experimental examples including preferred embodiments are presented to aid the understanding of the present invention, but these examples are only illustrative of the present invention and do not limit the scope of the appended claims, and the scope and spirit of the present invention It is obvious to those skilled in the art that various changes and modifications can be made to the embodiments within the scope, and it is natural that such modifications and modifications fall within the appended claims.

실시예Example

An ITO layer (0.1 μm) and a silver nanowire (AgNW) layer (0.2 μm) are stacked on the polyimide organic layer, and a touch sensor sample having an electrode having a width of 150 μm and an interval of 100 μm is formed on a glass substrate, and the touch The sensor sample was transferred onto the film. Thereafter, a supporting structure (PET layer: 23 μm, PSA layer: 50 μm) was formed on the electrodes.

비교예Comparative example

A touch sensor sample was prepared in the same manner as in Example except that the electrode was formed in a stacked structure of an APC layer (0.2 μm) and an ITO layer (0.1 μm).

굴곡 특성 평가Flexural property evaluation

The occurrence of cracks was evaluated while changing the curvature of the substrate including the electrodes of Examples and Comparative Examples. For each of the examples and comparative examples, the flexural characteristics were evaluated through the number of samples in which cracks occurred at each curvature. The evaluation results are as described in Table 1 below.

Referring to Table 1, in the case of the comparative example including the metal layer/ITO layer electrode, cracks occurred when the curvature was performed at 0.1R or less.

Claims

Display panel;

A touch sensor layer disposed on the display panel and including sensing electrodes and traces branching from the sensing electrodes and including at least one of silver nanowires, graphene, and carbon nanotubes;

A flexible circuit board electrically connected to the traces at one end of the touch sensor layer; And

And a support structure that commonly and partially covers the flexible circuit board and the touch sensor layer,

Ends of the display panel and the touch sensor layer are bent together with the support structure.
The flexible display module of claim 1, wherein the trace comprises silver nanowires, and optionally further comprises graphene or carbon nanotubes.
The method according to claim 1, wherein the sensing electrode and the trace each include a metal layer or a transparent conductive oxide layer,

The traces are formed on the metal layer or the transparent conductive oxide layer, and include a conductive capping layer including at least one of silver nanowires, graphene, and carbon nanotubes.
The flexible display module of claim 3, wherein the sensing electrode and the trace each include a stacked structure of the metal layer and the transparent conductive oxide layer.
The flexible display module of claim 3, wherein the conductive capping layer entirely covers an upper surface and a sidewall of the trace.
The flexible display module of claim 1, further comprising an optical layer covering sensing electrodes of the touch sensor layer.
The flexible display module of claim 6, wherein a gap is formed between the optical layer and the support structure.
The flexible display module of claim 7, further comprising a filling layer at least partially filling the gap.
The flexible display module of claim 8, wherein the filling layer comprises an adhesive resin.
The flexible display module of claim 6, wherein the ends of the display panel and the touch sensor layer are bent so that the flexible circuit board faces the optical layer.
The flexible display module of claim 10, further comprising a fixing structure inserted between portions of the display panel overlapping with the optical layer and the flexible circuit board facing each other.
The flexible display module of claim 6, wherein the optical layer comprises at least one selected from the group consisting of a polarizer, a polarizing plate, a retardation film, a reflective sheet, a brightness enhancing film, and a refractive index matching film.
The flexible display module of claim 1, further comprising a bonding layer bonding the display panel and the touch sensor layer.
The flexible display module of claim 1, wherein a curvature of the bent portion of the display panel and the touch sensor layer is 0.05R to 0.5R with respect to a radius of curvature R.
The flexible display module of claim 1, wherein the display panel comprises an organic light emitting diode (OLED) panel.
A flexible display module according to claim 1; And

An image display device comprising a window substrate disposed on the flexible display module.
The method according to claim 16, further comprising a main board disposed under the flexible display module,

The image display device, wherein the flexible circuit board of the flexible display module is electrically connected to the main board.