CN114089854A

CN114089854A - Touch panel, manufacturing method of touch panel and touch device

Info

Publication number: CN114089854A
Application number: CN202010862270.9A
Authority: CN
Inventors: 余建贤; 丁紫君; 徐云国; 方建华; 陈明培
Original assignee: TPK Advanced Solutions Inc
Current assignee: TPK Advanced Solutions Inc
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2022-02-25
Also published as: KR20220026458A; KR102423165B1; JP7263406B2; JP2022037855A

Abstract

A touch panel, a manufacturing method of the touch panel and a touch device are provided. The substrate is provided with a display area and a peripheral area, and is provided with a folding area and a non-folding area. The peripheral lead is arranged on the peripheral area of the substrate. The touch sensing electrode is arranged in the display area of the substrate and is provided with a first part positioned in the folding area and a second part positioned in the non-folding area. The touch sensing electrode is electrically connected with the peripheral lead and is provided with a grid pattern formed by interlacing a plurality of thin lines. The peripheral lead and the touch sensing electrode respectively comprise a plurality of conductive nanostructures and a film layer added to the conductive nanostructures, and the interface between the conductive nanostructures and the film layer in the second part of the peripheral lead and the touch sensing electrode is substantially provided with a coating structure. Therefore, the resistance-capacitance load value of the touch panel can be reduced, the narrow frame requirement of the display is met, and the flexibility of the touch panel is well maintained.

Description

Touch panel, manufacturing method of touch panel and touch device

Technical Field

The disclosure relates to a touch panel, a method for manufacturing the touch panel, and a touch device including the touch panel.

Background

In recent years, transparent conductors have been used in many display or touch related devices because they allow light to pass through and provide appropriate electrical conductivity. In general, the transparent conductor may be a thin film made of various metal oxides, such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Cadmium Tin Oxide (CTO), or aluminum-doped zinc oxide (AZO) thin film. However, these metal oxide thin films do not satisfy the flexibility requirements of display devices. Therefore, a variety of flexible transparent conductors, such as those made of nanoscale materials, are developed.

However, there are many problems to be solved in the above-mentioned process technology for nano-scale materials. For example, when the nanowire is used to manufacture the touch electrode, the touch electrode and the lead made of metal in the peripheral region need to be connected in an overlapping manner, and the size of the peripheral region cannot be reduced due to the overlapping region, so that the width of the peripheral region is large, and the narrow frame requirement of the display cannot be met. For another example, in order to consider optical effects, a resistance capacitive loading (RC loading) value of a touch electrode made of a nanowire is large, which is not favorable for general application.

Disclosure of Invention

According to some embodiments of the present disclosure, a touch panel includes a substrate, a peripheral lead, and a touch sensing electrode. The substrate is provided with a display area and a peripheral area, and is provided with a folding area and a non-folding area. The peripheral lead is arranged on the peripheral area of the substrate. The touch sensing electrode is arranged in the display area of the substrate and is provided with a first part positioned in the folding area and a second part positioned in the non-folding area. The touch sensing electrode is electrically connected with the peripheral lead and is provided with a grid pattern formed by interlacing a plurality of thin lines. The peripheral lead and the touch sensing electrode respectively comprise a plurality of conductive nanostructures and a film layer added to the conductive nanostructures, and the interface between the conductive nanostructures and the film layer in the second part of the peripheral lead and the touch sensing electrode is substantially provided with a coating structure.

In some embodiments, the coating structure includes a plating layer, and the plating layer completely covers an interface between the conductive nanostructure and the film layer.

In some embodiments, a film layer is filled between adjacent conductive nanostructures, and the film layer does not have a separate coating structure.

In some embodiments, the conductive nanostructure may include a metal nanowire, and the coating structure completely covers an interface between the metal nanowire and the film layer and forms a uniform coating layer at the interface between the metal nanowire and the film layer.

In some embodiments, the coating structure is a layer structure, an island-like protrusion structure, a dot-like protrusion structure, or a combination thereof made of a conductive material.

In some embodiments, the coating structure is an alloy coating structure of a silver coating structure, a gold coating structure, a copper coating structure, a nickel coating structure, a platinum coating structure, an iridium coating structure, a rhodium coating structure, a palladium coating structure, an osmium coating structure, or a combination thereof.

In some embodiments, the coating structure is a single-layer structure made of a single metal material or alloy material, or a two-layer or multi-layer structure made of two or more metal materials or alloys.

In some embodiments, the coating structure is an electroless copper layer, an electrolytic copper layer, an electroless nickel layer, an electroless copper silver layer, or a combination thereof.

In some embodiments, the conductive nanostructures and the film layer are in a first thin line.

In some embodiments, the conductive nanostructure, the film layer, and the coating structure are located in the first thin line of the second portion of the first touch sensing electrode.

In some embodiments, there is a boundary between the folded and non-folded regions, and the line width of the first thin line across the boundary gradually increases from away from the boundary to close to the boundary.

In some embodiments, the first fine line crossing the boundary has a first portion distal from the boundary and a second portion proximal to the boundary, the first portion having a line width between 1 micron and 5 microns, and the second portion having a line width between 5 microns and 30 microns.

In some embodiments, a boundary is located between the display region and the peripheral region of the folding region, and the line width of the first thin line adjacent to the boundary gradually increases from a distance from the boundary to a distance close to the boundary.

In some embodiments, the first thin line proximate the boundary has a first portion distal from the boundary and a second portion proximal to the boundary, the first portion having a line width between 1 micron and 5 microns, and the second portion having a line width between 5 microns and 30 microns.

In some embodiments, the substrate has a first surface and a second surface opposite to the first surface, the first touch sensing electrode is disposed on the first surface of the substrate, and the touch panel further includes a second touch sensing electrode disposed on the second surface of the substrate and the display area, wherein the second touch sensing electrode has a grid pattern formed by interlacing a plurality of second thin lines.

In some embodiments, the second touch sensing electrode has a first portion located in the folding region and a second portion located in the non-folding region, the second touch sensing electrode includes a conductive nanostructure and a film layer applied to the conductive nanostructure, and an interface between the conductive nanostructure and the film layer in the second portion of the second touch sensing electrode substantially has a coating structure.

In some embodiments, the grid-like pattern of alternating first thin lines does not completely overlap the grid-like pattern of alternating second thin lines.

According to other embodiments of the present disclosure, a method for manufacturing a touch panel includes: providing a substrate with a display area and a peripheral area, and a folding area and a non-folding area; arranging a plurality of conductive nano structures in the display area and the peripheral area to form a conductive layer; additionally arranging a film layer on the conductive layer, and enabling the film layer to reach a pre-curing or incomplete curing state; carrying out a patterning step; and performing a modification step to form a coating structure on the surfaces of the peripheral lead and the conductive nano structure in the touch sensing electrode in the non-folding area, so that the interface between the peripheral lead and the conductive nano structure in the touch sensing electrode in the non-folding area and the film layer substantially has the coating structure. The patterning step includes: patterning the conductive layer and the film layer in the display area of the folding area and the non-folding area to form a touch sensing electrode with a grid pattern formed by interlacing a plurality of thin lines; and patterning the conductive layer and the film layer in the peripheral area to form a peripheral lead.

In some embodiments, the patterning step is performed before the modifying step.

In some embodiments, the patterning of the conductive layer and the film layer in the display area and the peripheral area is performed in the same process.

In some embodiments, the modifying step further comprises masking the display region located in the folding region.

In some embodiments, the upgrading step comprises: and immersing the film layer and the conductive nano structure into a chemical plating solution, wherein the chemical plating solution permeates into the film layer and is contacted with the conductive nano structure, so that the metal is separated out on the surface of the conductive nano structure.

In some embodiments, the coating structure is formed along the surface of the conductive nanostructure and located at the interface between the conductive nanostructure and the film layer.

In some embodiments, applying a film layer over the conductive layer comprises: coating a polymer on the conductive layer; and controlling the curing conditions so that the polymer reaches a pre-cured or incompletely cured state.

In some embodiments, applying a film layer over the conductive layer comprises: coating a polymer on the conductive layer; and controlling the curing conditions so that the polymer reaches a pre-cured or incompletely cured state, wherein the film layer in the pre-cured or incompletely cured state is provided with a first layer area and a second layer area, and the curing state of the second layer area is higher than that of the first layer area.

In some embodiments, in the first layer region, a coating structure is formed along the surface of the conductive nanostructure and at the interface of the conductive nanostructure and the film layer.

In some embodiments, controlling the curing conditions may comprise: a gas is introduced and the respective concentrations of the gas in the first layer region and the second layer region are controlled.

In some embodiments, the modifying step comprises an electroless plating step, an electroplating step, or a combination thereof.

According to other embodiments of the present disclosure, a touch device includes the touch panel.

In some embodiments, the touch device includes a display, a portable phone, a tablet computer, a wearable device, a vehicle device, a notebook computer, or a polarizer.

According to the above-mentioned embodiments of the present disclosure, in the touch panel of the present disclosure, the peripheral leads located in the peripheral region and the touch sensing electrodes located in the display region are formed by the modified metal nanowires, so that the sheet resistance of the touch panel can be effectively reduced to improve the conductivity of the touch panel, and the resistive capacitive loading (RC loading) of the touch panel can be reduced. Moreover, the coating structure is not present in the folding area, so that the flexibility of the touch panel can be well maintained. On the other hand, because the touch sensing electrode positioned in the display area has a grid pattern formed by interlacing a plurality of thin lines, the light transmittance of the display area can be prevented from being influenced by the modified metal nano-wires, and the display area of the touch panel has good optical characteristics. In addition, in the manufacturing process of the touch panel, the peripheral lead and the touch sensing electrode can be manufactured through the steps of deposition and patterning in the same manufacturing process, so that the step of overlapping and the space occupied by overlapping can be omitted, the width of the peripheral area of the touch panel is further reduced, and the requirement of a narrow frame of a display is met.

Drawings

The foregoing and other objects, features, advantages and embodiments of the disclosure will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which:

fig. 1A-1C are schematic cross-sectional views illustrating various steps of a method for modifying metal nanowires according to some embodiments of the present disclosure;

FIG. 2A is a schematic top view of a touch panel according to some embodiments of the present disclosure;

FIG. 2B is a schematic cross-sectional view of the touch panel of FIG. 2A taken along line 2B-2B according to some embodiments of the present disclosure;

FIG. 2C is a partially enlarged schematic view of a region R1 of the touch panel of FIG. 2A according to some embodiments of the present disclosure;

FIG. 2D is a partially enlarged schematic view of a region R2 of the touch panel of FIG. 2A according to some embodiments of the present disclosure;

fig. 3A to 3D are schematic cross-sectional views illustrating different steps of a method for manufacturing a touch panel according to some embodiments of the present disclosure;

FIG. 4 is a schematic cross-sectional view illustrating a touch panel according to another embodiment of the present disclosure;

FIG. 5A is a schematic top view of a touch panel according to some other embodiments of the present disclosure; and

FIG. 5B is a cross-sectional view of the touch panel of FIG. 5A along line 5B-5B according to some embodiments of the present disclosure.

[ notation ] to show

100,100a,100b,100c touch Panel

110 base plate

120 metal nanowire layer

122 metal nanowires

130 film layer

140 coating structure

150 peripheral lead wire

170 touch control induction electrode

172 first touch sensing electrode

174 second touch sensing electrode

180 non-conductive area

190 protective layer

220 composite structure

PA peripheral area

VA display region

BR folding zone

NR-unfolded region

L is a fine wire

L1 first part

L2 second part

W1, W11, W12, W2 line widths

X1, X2 distance of lines

B1, B2 boundary

D1 first direction

D2 second direction

R1, R2 regions

2B-2B,5B-5B line segment

Detailed Description

In the following description, numerous implementation details are set forth in order to provide a thorough understanding of the present disclosure. It should be understood, however, that these implementation details are not to be interpreted as limiting the disclosure. That is, in some embodiments of the disclosure, these implementation details are not necessary, and thus should not be used to limit the disclosure. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner. In addition, the dimensions of the various elements in the drawings are not necessarily to scale, for the convenience of the reader.

Furthermore, relative terms, such as "lower" or "bottom" and "upper" or "top," may be used herein to describe one element's relationship to another element, as illustrated. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in a drawing were turned over, elements described as being on the "lower" side of other elements would then be oriented on "upper" sides of the other elements. Thus, the exemplary term "lower" can include both an orientation of "lower" and "upper," depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. Thus, the exemplary terms "below" or "beneath" can encompass both an orientation of above and below.

Further, as used herein, the term "about" or "approximately" generally means that the numerical error or range is within twenty percent, preferably within ten percent, and more preferably within five percent. Unless expressly stated otherwise, all numerical values mentioned are to be regarded as approximations, i.e., as having the error or range indicated by "about", "about" or "approximately".

It should be understood that "conductive nanostructure," as used herein, generally refers to a layer (layer) or film (film) composed of nanostructures that may have a sheet resistance of less than about 500 ohms/square, preferably less than about 200 ohms/square, and more preferably less than about 100 ohms/square; the term "nanostructure" as used herein generally refers to a structure having a nano-size, such as a linear structure, a columnar structure, a sheet structure, a lattice structure, a tubular structure, or a combination thereof, having at least one dimension (such as a wire diameter, a length, a width, or a thickness) in the nano-scale.

The present disclosure provides a method for modifying a conductive nanostructure (e.g., a metal nanowire), and a touch panel and a touch device fabricated using the modified conductive nanostructure. For clarity and convenience of description, the method for modifying the conductive nanostructure will be described first, and the metal nanowire is taken as an example.

Fig. 1A-1C are schematic cross-sectional views illustrating various steps of a method for modifying a metal nanowire according to some embodiments of the present disclosure. Referring to fig. 1A, first, a substrate 110 is provided, and metal nanowires 122 are coated on the surface of the substrate 110 to form a metal nanowire layer 120. The metal nanowire layer 120 may be, for example, but not limited to, a layer of silver nanowires, a layer of gold nanowires, or a layer of copper nanowires. In some embodiments, a dispersion or slurry containing the metal nanowires 122 may be coated on the substrate 110 and cured/dried to adhere the metal nanowires 122 to the surface of the substrate 110, thereby forming the metal nanowire layer 120 disposed on the substrate 110. After the curing/drying step, the solvent and other substances in the dispersion or slurry may be volatilized, and the metal nanowires 122 may be randomly distributed on the surface of the substrate 110; alternatively, the metal nanowires 122 can be fixed on the surface of the substrate 110 without falling off, thereby forming the metal nanowire layer 120,and the metal nanowires 122 in the metal nanowire layer 120 may contact each other to provide a continuous current path, thereby forming a conductive network (conductive network), that is, the metal nanowires 122 contact each other at crossing (overlapping) positions to form a path for transferring electrons. Taking silver nanowires as an example, one silver nanowire and another silver nanowire can form a direct contact state at the crossing position, so that a low-resistance path for transferring electrons can be formed. In some embodiments, when the sheet resistance of a region or a structure is greater than about 10⁸Ohm/square may be considered electrically insulating, preferably greater than about 10⁴Ohm/square, about 3000 ohm/square, about 1000 ohm/square, about 350 ohm/square, or about 100 ohm/square. In some embodiments, the sheet resistance of a layer of silver nanowires formed from silver nanowires is less than about 100 ohms/square.

Referring to fig. 1B, a film 130 is disposed to cover the metal nanowires 122, and the curing degree of the film 130 is controlled. In some embodiments, a suitable polymer may be coated on the metal nanowires 122, such that the polymer having a flowing state/property may penetrate between the metal nanowires 122 to form a filler, and further, the metal nanowires 122 are embedded in the film layer 130 to form the composite structure 220. On the other hand, the conditions for coating or curing the polymer (e.g., controlling the temperature and/or the photo-curing parameters) can be controlled to make the polymer in a pre-cured or incompletely cured state, or further make the film layer 130 have different degrees of curing. For example, the curing degree of the film 130 in the lower region (i.e., the region close to the substrate 110) may be adjusted to be greater than the curing degree of the film 130 in the upper region (i.e., the region far from the substrate 110), which may be in the pre-cured or incompletely cured state. In other words, in this step, a polymer is coated to add the film 130 on the metal nanowires 122, and the metal nanowires 122 are embedded in the film 130 in a pre-cured or incompletely cured state to form the composite structure 220.

In some embodiments, the film layer 130 may, for example, comprise an insulating material. For example, the insulating material may be a non-conductive resin or other organic material, such as may include, but is not limited to, polyacrylate, epoxy, polyurethane, polysilane, polysiloxane, poly (silicon-acrylic), polyethylene, polypropylene, polyvinyl butyral, polycarbonate, acrylonitrile-butadiene-styrene copolymer, poly (3, 4-ethylenedioxythiophene), poly (styrenesulfonic acid), or a ceramic material. In some embodiments, the film layer 130 can be formed by spin coating, spray coating, printing, or a combination thereof. In some embodiments, the thickness of the film layer 130 may be between about 20 nanometers and about 10 micrometers, between about 50 nanometers and about 200 nanometers, or between about 30 and about 100 nanometers, for example, the thickness of the film layer 130 may be, for example, about 90 nanometers or about 100 nanometers. It should be understood that, for brevity and clarity of disclosure, fig. 1B simply illustrates the metal nanowire layer 120 and the film layer 130 as an integral structural layer, but the disclosure is not limited thereto, and the metal nanowire layer 120 and the film layer 130 may also constitute other types of structural layers (e.g., stacked structures).

In some embodiments, the method of controlling the curing degree of the polymer may be performed by using curing conditions with different energies to achieve a pre-cured or incompletely cured state of the film layer 130. The curing degree of the film can be determined by the bonding change of the film during curing, that is, the curing degree of the film can be defined as the ratio (expressed as a percentage in the present embodiment) of the bonding strength of the film to the bonding strength of the fully cured film. For example, for a commercially available film material, it is required to irradiate the light energy of about 500mJ under a low oxygen environment for about 4 minutes to achieve complete curing, and the bonding strength measured by infrared spectroscopy after irradiating the light energy of about 500mJ under a low oxygen environment for about 2 minutes is about 95% of the bonding strength of the completely cured film, which represents the curing degree of the film reaching about 95% of the total curing amount, and thus defines the curing state of the film obtained under the curing condition as about 95% of the total curing amount.

In some embodiments, the controllable film layer 130 has different curing states at different depths (i.e., thicknesses). Specifically, gas may be introduced during the curing of the film 130, so that the gas concentrations at the top and the bottom of the film 130 are different, and further, the curing reaction at the top of the film 130 is promoted to generate a gas blocking curing phenomenon, so that the film 130 has a first layer region and a second layer region with different curing degrees. For example, the second layer region may be located at the bottom of the film 130 and be a region with a higher degree of curing, while the first layer region may be located at the top of the film 130 and be a region with a lower degree of curing. In some embodiments, the concentration of the gas (e.g., oxygen) introduced during curing and/or the curing energy imparted can be controlled to provide different curing states at different depths of the film 130. In some embodiments, the concentration of the gas may be, for example, about 20%, about 10%, about 3%, or less than about 1%, and the curing energy may be selected according to the material of the film 130, such as ultraviolet energy between about 250mJ and about 1000 mJ. In some embodiments, the greater the concentration of the gas, the more significant the oxygen-blocking cure occurs at the top of the film 130, such that the greater the thickness of the first layer region and the smaller the thickness of the second layer region. For example, the thickness of the first layer region is from about 20%, about 10%, about 3%, and less than about 1% in the order of the concentration of the introduced gas. In some embodiments, when oxygen is introduced at a concentration of about 20% and curing energy of about 500mJ is applied, the first layer region has a degree of cure of about 60% and a thickness of about 23.4 nm (i.e., about 12% of the total thickness of the film layer 130); and the second layer region is cured to a degree of between about 99% and about 100% and has a thickness of about 168.1 nm (i.e., about 88% of the total thickness of the layer 130). In some embodiments, the thickness of the first layer region is about 8.8 nm (i.e., about 5% of the total thickness of the film layer 130) when oxygen is introduced at a concentration of about 20% and curing energy is applied at about 1000 mJ; while the thickness of the second layer region is about 195.9 nanometers (i.e., about 95% of the total thickness of the film layer 130).

It should be noted that the present disclosure focuses on discussing the film 130 applied to the metal nanowires 122, and by controlling the curing degree or curing depth of the film 130, a coating structure 140 (not shown in fig. 1B, please refer to fig. 1C for details) can be grown along the surface of the metal nanowires 122 to form at the interface between the metal nanowires 122 and the film 130 (this part will be described in detail later). In the coating step of the dispersion or slurry containing the metal nanowires 122, the dispersion or slurry may also contain a polymer or the like, but it is not the focus of the present disclosure. In some embodiments, the degree of curing of the film layer 130 may be controlled to be in a state of about 0%, about 30%, about 60%, about 75%, about 95%, about 98%, about 0% to about 95%, about 0% to about 98%, about 95% to about 98%, about 60% to about 98%, or about 60% to about 75%. As mentioned above, the term "pre-cured or not fully cured" as used herein can be defined as the bonding strength of the film is different from the bonding strength of the fully cured film, i.e. the ratio of the two is not 100%, and is within the scope of the present disclosure.

Referring to fig. 1C, a modification step is performed to form a metal nanowire layer 120 including a plurality of modified metal nanowires 122. In detail, after the modification, at least a portion of the original metal nanowire 122 is modified to form the coating structure 140 on the surface thereof, thereby forming the modified metal nanowire 122. It should be understood that different dots are used in fig. 1B and fig. 1C to represent the metal nanowire 122 before and after modification, respectively, and the dots in fig. 1B and fig. 1C will be directly used in the subsequent figures to represent the metal nanowire 122 before and after modification, respectively. In some embodiments, the coating structure 140 may be formed by electroless plating/electrolysis, and the coating structure 140 may be, for example, a layered structure including a conductive material, an island-shaped protrusion structure, a dot-shaped protrusion structure, or a combination thereof. In some embodiments, the conductive material can include silver, gold, platinum, nickel, copper, iridium, rhodium, palladium, osmium, alloys including or excluding the foregoing materials. In some embodiments, the coating rate of the coating structure 140 may account for more than about 80%, from about 90% to about 95%, from about 90% to about 99%, or from about 90% to about 100% of the total surface area of the metal nanowires 122. It should be understood that when the coating rate of the coating structure 140 is 100%, it means that the surface of the original metal nanowire 122 is not exposed at all. In some embodiments, the coating structure 140 may be a single layer structure made of a single conductive material, such as an electroless copper plating layer, an electrolytic copper plating layer, or an electroless copper nickel plating alloy layer; alternatively, the coating structure 140 may be a two-layer or multi-layer structure made of more than two conductive materials, such as an electroless copper layer and an electroless silver layer.

In some embodiments, an electroless copper plating solution (including a copper ion solution, a chelating agent, an alkaline agent, a reducing agent buffer, a stabilizer, etc.) may be prepared and the metal nanowires 122 and the film layer 130 are immersed in the electroless copper plating solution. The electroless copper plating solution may penetrate into the pre-cured or incompletely cured film 130, and contact the surface of the metal nanowire 122 by using a capillary phenomenon, and simultaneously, the metal nanowire 122 is used as a catalytic point or a nucleation point to facilitate the precipitation of copper, so that an electroless copper plating layer is deposited on the metal nanowire 122 to form the coating structure 140. The coating structure 140 is grown substantially according to the initial shape of the metal nanowire 122, and forms a structure coating the metal nanowire 122 with the increase of the modification time. In contrast, there is no copper deposition at the position of the composite structure 220 where there is no metal nanowire 122, that is, with good control, the coating structures 140 are all formed at the interface between the metal nanowire 122 and the film layer 130, and the film layer 130 does not have the coating structure 130 that does not contact the surface of the metal nanowire 122 and exists alone. Therefore, after the modification step, the metal nanowires 122 in the conductive network are covered by the covering structure 140, and the covering structure 140 is located on the interface formed by the metal nanowires 122 and the film 130. In other words, the coating structure 140 is spaced between the metal nanowires 122 and the film 130. The coating structure 140 and the metal nanowires 122 coated by the coating structure can be regarded as a whole, and the gap between the whole is still occupied by the material of the film 130.

In some embodiments, the film 130 and the electroless/electrolytic solution may be compatible materials, such as polymers with poor alkali resistance to form the film 130, and the electroless/electrolytic solution may be an alkaline solution. Therefore, in this step, in addition to utilizing the desired cured or incompletely cured state of the film 130, the film 130 that is pre-cured or incompletely cured can be attacked (like etching) by the electroless plating solution to facilitate the modification step.

The following description is illustrative of the principles for performing the modification step and is not intended to limit the present disclosure. At the beginning of immersing the metal nanowires 122 and the film 130 into the electroless plating solution/electrolytic solution, the solution will attack the pre-cured or not-fully-cured film 130, and when the solution contacts the metal nanowires 122, metal ions (e.g., copper ions) will start to grow from the metal nanowires 122 (e.g., silver nanowires) as seeds, and grow on the surface of the metal nanowires 122 as the immersion time increases to form the coating structure 140. On the other hand, the film layer 130 may serve as a control layer or a limiting layer in the above reaction process to limit the growth reaction of the coating structure 140 at the interface between the metal nanowire 122 and the film layer 130, so that the coating structure 140 can be grown in a controlled and uniform manner. In this way, the modified metal nanowire 122 of the present disclosure has better consistency in sensing/transmitting signals.

In some embodiments, a curing step may follow to complete curing of the film layer 130 using light, heat, or other means. In the modification step, the coating structure 140 is formed on the surface of each metal nanowire 122, and coats the entire surface of each metal nanowire 122 and grows outward. In some embodiments, the coating structure 140 may be made of a highly conductive material, such as copper, as the material of the coating structure 140 to cover the surface of the silver nanowires, and the coating structure 140 is located at the interface between the silver nanowires and the film layer 130. It should be noted that although the conductivity of the silver metal material is higher than that of the copper metal material, due to the size of the silver nanowires and the contact state of the silver nanowires, the overall conductivity of the silver nanowire layer is lower (but the resistance is still low enough to transmit the electrical signal), and after the modification step, the conductivity of the silver nanowires covered with the coating structure 140 (i.e., the modified metal nanowires 122) is higher than that of the unmodified silver nanowires. In other words, the modified metal nanowire layer 120 can form a low-resistance conductive layer, and the surface resistance of the modified metal nanowire layer 120 can be reduced by about 100 times to about 10000 times compared to the unmodified metal nanowire layer 120. The conductive layer can be used for manufacturing electrode structures with various purposes, such as conductive substrates in flexible fields, wireless charging coils or antenna structures. Specifically, the electrode structure may at least include the metal nanowire 122 and the film layer 130 additionally coated on the metal nanowire 122, and at least a portion or all of the surface of the metal nanowire 122 (i.e., the interface between the metal nanowire 122 and the film layer 130) has a coating structure 140 (i.e., a coating layer). By introducing the cladding layer, the conductivity of the metal nanowire layer 120 can be improved. In some embodiments, since the copper material is grown along the surface of the metal nanowires 122 (i.e., the interface between the metal nanowires 122 and the film 130), the observed copper morphology after plating is relatively similar to the initial morphology (e.g., line-like structure) of the metal nanowires 122, and the copper grows uniformly to form an outer layer structure with similar dimensions (e.g., thickness).

The method of the present disclosure can be applied to manufacturing a touch panel, such as but not limited to a touch panel used with a display. More specifically, referring to fig. 2A and fig. 2B, fig. 2A is a schematic top view of the touch panel 100 according to some embodiments of the present disclosure, and fig. 2B is a schematic cross-sectional view of the touch panel 100 of fig. 2A taken along the line 2B-2B according to some embodiments of the present disclosure. In some embodiments, the touch panel 100 may include a substrate 110, a peripheral lead 150, and a touch sensing electrode 170. The substrate 110 is configured to carry the peripheral leads 150 and the touch sensing electrodes 170, and may be a rigid transparent substrate or a flexible transparent substrate, for example. In some embodiments, the material of the substrate 110 includes, but is not limited to, glass, acryl, polyvinyl chloride, polypropylene, polystyrene, polycarbonate, cyclic olefin polymer, cyclic olefin copolymer, polyethylene terephthalate, polyethylene naphthalate, colorless polyimide, and other transparent materials, or combinations thereof. In some embodiments, a pretreatment process may be performed on the surface of the substrate 110, such as a surface modification process or an additional coating of an adhesive layer or a resin layer on the surface of the substrate 110, so as to improve the adhesion between the substrate 110 and the metal nanowires 122.

In some embodiments, if defined according to the visibility, the substrate 110 may have a display area VA and a peripheral area PA, and the peripheral area PA is disposed at a side of the display area VA, where the display area VA is a region that can be viewed by a user, the peripheral area PA is a region that cannot be viewed by the user, and a boundary B2 is located at a boundary between the display area VA and the peripheral area PA. For example, the peripheral area PA may be disposed in a frame-shaped area around the display area VA (i.e. covering the right side, the left side, the upper side and the lower side). For example, the peripheral area PA may also be an L-shaped area disposed on the left and lower sides of the display area VA. In some embodiments, if defined by flexibility, the substrate 110 has a folding region BR and a non-folding region NR, and the non-folding region NR can sandwich the folding region BR therebetween (e.g., sandwich the folding region BR from the upper side and the lower side), wherein the boundary between the folding region BR and the non-folding region NR has a boundary B1. The definition of the folding region BR may be, for example, a bendable region defined by the design of the flexible device when the touch panel 100 is integrated into the flexible device. Overall, the area of the folding region BR is smaller than the area of the non-folding region NR. In some embodiments, the peripheral region PA and the display region VA respectively have a partial region overlapping the folding region BR and a partial region overlapping the non-folding region NR.

In some embodiments, the touch sensing electrodes 170 are substantially located in the display area VA, wherein a portion of the touch sensing electrodes 170 are located in the folding area BR, and another portion of the touch sensing electrodes 170 are located in the non-folding area NR. In some embodiments, the touch sensing electrodes 170 are arranged in a non-staggered manner, for example, the touch sensing electrodes 170 may be strip-shaped electrodes extending along the first direction D1, and the strip-shaped electrodes may be arranged equidistantly along the second direction D2, wherein the first direction D1 is perpendicular to the second direction D2. However, the shape and arrangement of the touch sensing electrodes 170 are not limited thereto, and in other embodiments, the touch sensing electrodes 170 may have other suitable shapes and arrangements. In some embodiments, the same strip-type electrode may span the folding region BR and the non-folding region NR (e.g., the uppermost strip-type electrode in fig. 2A), be completely located in the folding region BR (e.g., the middle strip-type electrode in fig. 2A), or be completely located in the non-folding region NR (e.g., the lowermost strip-type electrode in fig. 2A). In some embodiments, the touch sensing electrodes 170 are configured as a single layer, and the touch panel 100 can obtain the touch position by detecting the capacitance variation of each touch sensing electrode 170.

In some embodiments, the peripheral lead 150 is substantially located in the peripheral area PA, and the peripheral lead 150 and the touch sensing electrode 170 are substantially in contact with each other at a boundary (boundary B2) between the display area VA and the peripheral area PA, so as to be electrically connected to each other to form an electron transfer path crossing the display area VA and the peripheral area PA. In some embodiments, the peripheral leads 150 may be connected to an external controller for touch or other signal transmission.

In some embodiments, the peripheral lead 150 and the touch sensing electrode 170 in the non-folding region NR are formed by modified metal nanowires 122 (the modified metal nanowires 122 include the metal nanowires 122 and the covering structure 140 covering the surface thereof). In detail, the peripheral lead 150 and the touch sensing electrode 170 in the non-folding region NR each include a metal nanowire 122 and a film 130 added to the metal nanowire 122, and an interface between each metal nanowire 122 and the film 130 substantially has a covering structure 140. Specifically, the modified metal nanowire 122 and the film layer 130 added to the modified metal nanowire 122 are patterned to form the peripheral lead 150 and the touch sensing electrode 170 in the non-folding region NR. The modified metal nanowire 122 is formed by molding the coating structure 140 on the interface between the metal nanowire 122 and the film layer 130, and the modified metal nanowire 122 is used to manufacture the peripheral lead 150 of the touch panel 100 and the touch sensing electrode 170 located in the non-folding region NR, so that the area resistance of the touch panel 100 can be effectively reduced to improve the conductivity of the touch panel 100, and the resistive and capacitive loading (RC loading) of the touch panel 100 can be effectively reduced. In some embodiments, the resistance-capacitance loading of the touch-sensing electrode 170 made of the modified metal nanowires 122 is reduced by about 10% to about 50% compared to the resistance-capacitance loading of the touch-sensing electrode 170 made of the unmodified metal nanowires 122 (i.e., the metal nanowires 122 without the coating structure 140 on the surface).

In some embodiments, the touch sensing electrode 170 in the folding region BR is composed of unmodified metal nanowires 122. In more detail, the touch sensing electrode 170 in the folding region BR includes an initial metal nanowire 122 and a film layer 130 added to the metal nanowire 122. Specifically, the unmodified metal nanowire 122 and the film layer 130 applied to the unmodified metal nanowire 122 are patterned to form the touch sensing electrode 170 in the folding region BR. It should be noted that, since the unmodified metal nanowire 122 (e.g., a silver nanowire) can have better flexibility than the modified metal nanowire 122 (e.g., a silver nanowire covered with a copper metal material), the touch panel 100 can maintain good flexibility by using the unmodified metal nanowire 122 to fabricate the touch sensing electrode 170 in the folding region BR. On the other hand, although the touch sensing electrode 170 made of the modified metal nanowire 122 has a lower rc loading value than the touch sensing electrode 170 made of the unmodified metal nanowire 122, the touch sensing electrode 170 made of the modified or unmodified metal nanowire 122 has a good enough conductivity to transmit the touch sensing signal.

In some embodiments, the touch sensing electrode 170 has a grid pattern formed by a plurality of thin lines L being interlaced. In detail, in the non-folding region NR, the modified metal nanowire 122 and the film layer 130 applied to the modified metal nanowire 122 are patterned to form a grid pattern formed by interlacing a plurality of thin lines L, and the formed grid pattern is an electrode pattern of the touch sensing electrode 170; in the folding region BR, the unmodified metal nanowire 122 and the film layer 130 applied to the unmodified metal nanowire 122 are patterned to form a grid pattern formed by interlacing a plurality of thin lines L, and the formed grid pattern is an electrode pattern of the touch sensing electrode 170. In other words, the modified metal nanowire 122 and the film layer 130 added to the modified metal nanowire 122 exist in each thin line L of the touch sensing electrode 170 in the non-folding region NR; the unmodified metal nanowire 122 and the film layer 130 applied to the unmodified metal nanowire 122 exist in each thin line L of the touch sensing electrode 170 in the folding region BR. When the same touch sensing electrode 170 crosses the boundary B1 between the folding region BR and the non-folding region NR, the thin line L crossing the boundary B1 can have both the unmodified metal nanowire 122 and the modified metal nanowire 122. In more detail, when one metal nanowire 122 in the same filament L crosses the boundary B1 between the folding region BR and the non-folding region NR, the metal nanowire 122 crossing the boundary B1 may be partially modified, that is, a portion of the metal nanowire 122 may be coated with the coating structure 140 (i.e., modified), and another portion may not be coated with the coating structure 140 (i.e., unmodified).

It should be noted that, since the modified metal nanowire 122 has the coating structure 140, it has a lower light transmittance (i.e., a visible light transmittance with a wavelength of about 400nm to about 700 nm) and a higher haze compared to the unmodified metal nanowire 122, and the modified metal nanowire 122 can be prevented from affecting the light transmittance and the haze of the touch sensing electrode 170 by patterning the touch sensing electrode 170 to form a grid pattern formed by interlacing a plurality of thin lines L, so that the display area VA of the touch panel 100 can maintain good optical characteristics. Specifically, the touch sensing electrode 170 with the grid pattern of the present disclosure can make the display area VA of the touch panel 100 have a light transmittance greater than about 88%, which meets the requirement of the user. On the other hand, the touch sensing electrode 170 with the grid pattern of the present disclosure may enable the display area VA of the touch panel 100 to have a haze of less than about 3.0, and preferably less than about 2.5, about 2.0, or about 1.5.

In some embodiments, the line width W1 of each thin line L is between about 1 micron and about 30 microns, so as to provide better light transmittance for the touch sensing electrode 170 and provide convenience for patterning. In detail, when the line width W1 of each thin line L is greater than about 30 μm, the touch sensing electrode 170 may have poor light transmittance, which may affect the optical characteristics of the display area VA of the touch panel 100; when the line width W1 of each thin line L is smaller than about 1 μm, the patterning difficulty may be increased, thereby causing inconvenience in the manufacturing process. In some embodiments, the distance X1 between adjacent thin lines L (i.e., line distance X1) is between about 1 micron and about 10 microns to provide better light transmittance and electrical conductivity for the touch sensing electrode 170. In detail, when the line distance X1 is greater than about 10 μm, the grid patterns may be arranged too sparsely, which results in insufficient electron transmission paths, and thus causes an excessively large area resistance and an excessively low conductivity of the touch sensing electrode 170; when the line distance X1 is less than about 1 μm, the grid patterns may be arranged too tightly, which may cause the light transmittance of the touch sensing electrode 170 to be too low, and thus the optical characteristics of the display area VA of the touch panel 100 may be affected. In some embodiments, the thin lines L may be arranged, for example, in an equidistant manner, i.e., each grid may have the same dimensions (e.g., length and width). In some embodiments, the shape of each grid may be, for example, rectangular, square, diamond, or other suitable shape. Through the above arrangement, the touch sensing electrode 170 of the present disclosure has good light transmittance and good electrical conductivity. Specifically, the area resistance of the touch sensing electrode 170 with the grid pattern formed by the modified metal nanowires 122 in the non-folding region NR is between about 8 ohm/square and about 42 ohm/square, which is further reduced by about 20% to about 30% compared to the area resistance of the touch sensing electrode 170 with the grid pattern formed by the unmodified metal nanowires 122 in the folding region BR.

In some embodiments, the thin line L crossing the boundary B1 of the folding region BR and the non-folding region NR in the touch sensing electrode 170 may have a non-uniform line width W1. In detail, please refer to fig. 2C, which is a partially enlarged schematic view illustrating a region R1 of the touch panel 100 of fig. 2A according to some embodiments of the present disclosure. As shown in fig. 2C, a thin line L crossing a boundary B1 of the folding region BR and the non-folding region NR has a first portion L1 farther from the boundary B1 and a second portion L2 closer to the boundary B1, in which the first portion L1 is connected to the second portion L2, and a line width W11 of the first portion L1 is smaller than a line width W12 of the second portion L2. In more detail, the line width W11 of the first portion L1 is between 1 micron and 5 microns, and the line width W12 of the second portion L2 is between 5 microns and 30 microns. Since the folding region BR is provided with the unmodified metal nanowire 122, and the non-folding region NR is provided with the modified metal nanowire 122, through the design of the uneven line width W1 of the thin line L, the circuit (thin line L) can be prevented from being broken (open) between the folding region BR and the non-folding region NR after being bent for multiple times, and at the same time, the display region VA can be ensured to have good optical characteristics (e.g. high light transmittance). In some embodiments, the line width W1 of the thin line L crossing the boundary B1 is gradually increased and gradually decreased at a constant amplitude, that is, a linearly tapered design is employed. In more detail, the line width W1 of the thin line L crossing the boundary B1 increases from being far from the boundary B1 to being close to the boundary B1 in the folding region BR, and decreases from being close to the boundary B1 to being far from the boundary B1 in the non-folding region NR, so that the thin line L crossing the boundary B1 has the largest line width W1 at the contact boundary B1. Since the line width W1 of the thin line L is decreased (increased) at a constant magnitude, disconnection of the line due to a sudden decrease (increase) in the line width W1 can be avoided. On the other hand, a thin line L that does not cross the boundary B1 may have a fixed line width W1 (as shown in fig. 2A).

Referring back to fig. 2A, in some embodiments, the thin line L adjacent to the boundary B2 between the display area VA and the peripheral area PA in the touch sensing electrode 170 may also have a non-uniform line width W1. In detail, please refer to fig. 2D, which is a partially enlarged schematic view illustrating a region R2 of the touch panel 100 of fig. 2A according to some embodiments of the present disclosure. As shown in fig. 2D, in the folding region BR, the thin line L adjacent to the boundary B2 between the display region VA and the peripheral region PA has a first portion L1 farther from the boundary B2 and a second portion L2 closer to the boundary B2, wherein the first portion L1 is connected to the second portion L2, and the line width W11 of the first portion L1 is smaller than the line width W12 of the second portion L2. In more detail, the line width W11 of the first portion L1 is between 1 micron and 5 microns, and the line width W12 of the second portion L2 is between 5 microns and 30 microns. Since the unmodified metal nanowires 122 are disposed in the display area VA of the folding area BR, and the modified metal nanowires 122 are disposed in the peripheral area PA of the folding area BR, by designing the non-uniform line width W1 of the thin line L, it is able to prevent the circuit of the folding area BR from being broken between the display area VA and the peripheral area PA after being bent for multiple times, and to ensure good optical characteristics (e.g., high light transmittance) of the display area VA. In some embodiments, the line width W1 of the thin line L immediately adjacent to the boundary B2 is gradually increased at a constant magnitude, i.e., a linear gradation design is employed. More specifically, the line width W1 of the thin line L adjacent to the boundary B2 increases from being far from the boundary B2 to being close to the boundary B2 in the display area VA, and extends to the boundary B2 to connect the peripheral circuit 150, so that the thin line L has the maximum line width W1 at the contact boundary B2 (i.e., at the connection peripheral circuit 150). Since the line width W1 of the thin line L is decreased (increased) at a constant magnitude, disconnection of the line due to a sudden decrease (increase) in the line width W1 can be avoided. On the other hand, the thin line L not adjacent to the boundary B2 may have a fixed line width W1.

Referring back to fig. 2A and 2B, the line width W2 of the peripheral wire 150 is between about 8 microns and about 10 microns, so that the peripheral wire 150 has good conductivity and provides convenience for patterning. In detail, when the line width W2 of the peripheral lead 150 is smaller than about 8 μm, the sheet resistance of the peripheral lead 150 may be too high and the conductivity may be too low, and the patterning difficulty may be increased, thereby causing inconvenience in the manufacturing process. In some embodiments, the line width W2 of the peripheral lead 150 may be designed to be the same as the line width W1 of the thin line L (the thin line L not adjacent to the boundaries B1 and B2) in the touch sensing electrode 170. In some embodiments, the distance X2 (i.e., the line distance X2) between adjacent peripheral leads 150 is between about 5 microns and about 20 microns, or preferably between 3 microns and about 20 microns, so that the touch panel 100 of the present disclosure has a reduced bezel size (e.g., width of the peripheral region PA) of about 20% or more compared to a conventional touch panel, thereby meeting the narrow bezel requirement of the display. Specifically, the width of the peripheral area PA of the touch panel 100 of the present disclosure may be less than about 2 mm. With the above arrangement, the peripheral lead 150 of the present disclosure has good conductivity. Specifically, the peripheral wires 150 of the present disclosure may make the area resistance of the peripheral area PA of the touch panel 100 be between about 0.10 ohm/square and about 0.13 ohm/square, which is reduced by about 20% to about 50% compared to the area resistance of the peripheral area PA of the touch panel formed by the unmodified metal nanowires 122.

Referring to fig. 3A to 3D, cross-sectional views of a method for manufacturing a touch panel 100 according to some embodiments of the present disclosure at different steps are shown, where the cross-sectional positions are the same as those of fig. 2B. The method for manufacturing the touch panel 100 includes steps S10 to S16, and steps S10 to S16 may be performed sequentially. In step S10, the substrate 110 having the predefined peripheral region PA and display region VA and the folding region BR and non-folding region NR is provided, and the unmodified metal nanowires 122 are disposed on the substrate 110, so as to form the metal nanowire layer 120 in the peripheral region PA and the display region VA (including the regions in the folding region BR and the non-folding region NR). In step S12, the film 130 is disposed on the unmodified metal nanowires 122, such that the film 130 covers the unmodified metal nanowires 122, and the film 130 is in a pre-cured or incompletely cured state. In step S14, a patterning step is performed to form a patterned metal nanowire layer 120, wherein the metal nanowire layer 120 in the peripheral region PA is patterned to form the peripheral wires 150, and the metal nanowire layer 120 in the display region VA (including the regions in the folding region BR and the non-folding region NR) is patterned to form the touch sensing electrode 170. In step S16, a modification step is performed to mold the coating structure 140 on a portion of the metal nanowires 122, such that the peripheral lead 150 in the peripheral region PA and the touch sensing electrode 170 in the non-folding region NR are formed by the modified metal nanowires 122, and the touch sensing electrode 170 in the folding region BR is formed by the unmodified metal nanowires 122. Hereinafter, the above steps will be explained in more detail.

Referring to fig. 3A, a metal nanowire layer 120 (e.g., a nano-silver wire layer, a nano-gold wire layer, or a nano-copper wire layer) at least containing metal nanowires 122 is coated on the peripheral region PA and the display region VA (including the regions located in the folding region BR and the non-folding region NR) of the substrate 110. In some embodiments, a dispersion or slurry with metal nanowires 122 may be formed on the substrate 110 by coating, and cured/dried to attach the metal nanowires 122 to the surface of the substrate 110, thereby forming the metal nanowire layer 120 disposed on the substrate 110. After the curing/drying step, the solvent and other substances in the dispersion or slurry may be volatilized, and the metal nanowires 122 may be randomly distributed on the surface of the substrate 110; alternatively, preferably, the metal nanowires 122 can be fixed on the surface of the substrate 110 without falling off, so as to form the metal nanowire layer 120, and the metal nanowires 122 in the metal nanowire layer 120 can contact each other to provide a continuous current path, so as to form a conductive network. In other words, the metal nanowires 122 contact each other at crossing positions to form paths for transferring electrons. Taking silver nanowires as an example, a state of direct contact (i.e., a silver-silver contact interface) is formed at the intersection of one silver nanowire and another silver nanowire, so that a low-resistance electron-transferring path can be formed, and the subsequent modification step does not affect or change the low-resistance structure of the "silver-silver contact", and the surface of the metal nanowire 122 is coated with the coating structure 140 with high conductivity, so that the electrical characteristics of the terminal product can be improved.

In some embodiments, the dispersion or slurry includes a solvent, thereby uniformly dispersing the metal nanowires 122 therein. Specifically, the solvent is, for example, water, alcohols, ketones, ethers, hydrocarbons, aromatic solvents (benzene, toluene, xylene, or the like), or any combination thereof. In some embodiments, the dispersion may further include an additive, a surfactant and/or a binder, thereby improving the compatibility between the metal nanowires 122 and the solvent and the stability of the metal nanowires 122 in the solvent. Specifically, the additive, surfactant and/or binder may be, for example, carboxymethylcellulose, hydroxyethylcellulose, hypromellose, a fluorosurfactant, sulfosuccinate sulfonate, sulfate, phosphate, disulfonate, or a combination thereof. The dispersion or slurry containing the metal nanowires 122 can be formed on the surface of the substrate 110 by any method, such as but not limited to screen printing, nozzle coating, or roller coating. In some embodiments, a roll-to-roll process may be used to apply the dispersion or slurry comprising the metal nanowires 122 to the surface of the continuously supplied substrate 110.

It should be understood that "metal nanowire" as used herein is a collective term referring to a collection of metal wires comprising a plurality of metal elements, metal alloys or metal compounds (including metal oxides), and the number of metal nanowires contained therein does not affect the scope of protection claimed by the present disclosure. In some embodiments, the cross-sectional dimension (e.g., the diameter of the cross-section) of a single metal nanowire may be less than 500nm, preferably less than 100nm, and more preferably less than 50 nm. In some embodiments, the metal nanowires have a large aspect ratio (i.e., length: diameter of cross-section). In particular, the aspect ratio of the metal nanowire may be between 10 and 100000. In more detail, the aspect ratio of the metal nanowire may be greater than 10, preferably greater than 50, and more preferably greater than 100. In addition, other terms such as silk (silk), fiber (fiber), or tube (tube) having the above cross-sectional dimensions and aspect ratios are also within the scope of the present disclosure.

In some embodiments, the metal nanowires 122 may be further post-processed to improve the contact characteristics (e.g., increase the contact area) of the metal nanowires 122 at the crossing points, thereby improving the conductivity thereof. This post-treatment may include, for example, but is not limited to, heating, plasma, corona discharge, ultraviolet light, ozone, or pressure. Specifically, after curing/drying to form the metal nanowire layer 120, a roller may be used to apply pressure thereon. In some embodiments, one or more rollers may be used to apply pressure to the metal nanowire layer 120. In some embodiments, the applied pressure may be between about 50psi to about 3400psi, preferably between about 100psi to about 1000psi, about 200psi to about 800psi, or about 300psi to about 500 psi. In some embodiments, the metal nanowires 122 may be subjected to post-treatment of the heating and pressurizing steps simultaneously. For example, a pressure of about 10psi to about 500psi (or preferably about 40psi to about 100 psi) can be applied through the roller while heating the roller to about 70 ℃ to about 200 ℃ (or preferably about 100 ℃ to about 175 ℃) to increase the conductivity of the metal nanowires 122. In some embodiments, the metal nanowires 122 may be post-treated by exposure to a reducing agent, for example, the metal nanowires 122 composed of nano-silver wires may preferably be post-treated by exposure to a silver reducing agent. In some embodiments, the silver reducing agent may include a borohydride, such as sodium borohydride, a boron nitrogen compound, such as dimethylaminoborane, or a gaseous reducing agent, such as hydrogen gas. In some embodiments, the exposure time may be between about 10 seconds to about 30 minutes, preferably between about 1 minute to about 10 minutes. Through the post-treatment step, the contact strength or area of the metal nanowire 122 at the intersection can be enhanced, and the contact surface of the metal nanowire 122 at the intersection is ensured not to be affected by the modification treatment.

Next, referring to fig. 3B, a film 130 is disposed on the unmodified metal nanowire 122, such that the film 130 covers the unmodified metal nanowire 122. In some embodiments, the polymer in the coated film layer 130 may penetrate between the metal nanowires 122 to form a filler, and the metal nanowires 122 may be embedded in the film layer 130 to form the composite structure 220. In other words, the unmodified metal nanowires 122 are embedded in the film 130 to form the composite structure 220. In some embodiments, the film layer 130 may include an insulating material, such as a non-conductive resin or other organic material. In some embodiments, the film layer 130 can be formed by spin coating, spray coating, printing, or the like. In some embodiments, the thickness of the film layer 130 may be between about 20 nanometers and about 10 micrometers, between about 50 nanometers and about 200 nanometers, or between about 30 and about 100 nanometers. To effectively perform the subsequent modification step, the polymer (i.e., the film layer 130) is in a pre-cured or incompletely cured state, which can be specifically referred to the above description.

Subsequently, referring to fig. 3C, a patterning step is performed to pattern the composite structure 220 in the peripheral area PA and the display area VA, so as to form conductive structures in the peripheral area PA and the display area VA. In some embodiments, the patterned composite structure 220 fabricated in the peripheral area PA may form the peripheral lead 150, the patterned composite structure 220 fabricated in the display area VA may form the touch sensing electrode 170, and the peripheral lead 150 and the touch sensing electrode 170 may be electrically connected to each other for signal transmission between the peripheral area PA and the display area VA. In other words, the peripheral lead 150 and the touch sensing electrode 170 may be patterned from the same layer of the composite structure 220. In some embodiments, the composite structure 220 located in the display area VA may be patterned into a grid pattern by interleaving a plurality of thin lines L, so that the display area VA has good light transmittance. After the patterning step, the peripheral lead 150 and the touch sensing electrode 170 may at least include the metal nanowire layer 120 formed by the unmodified metal nanowires 122.

In some embodiments, the patterning of the composite structure layer 220 may be performed by etching. In some embodiments, the composite structure 220 in the peripheral area PA and the display area VA may be etched simultaneously, and an etching mask (e.g., photoresist) may be used to fabricate the patterned composite structure 220 in the peripheral area PA and the display area VA in one process. In some embodiments, when the metal nanowire layer 120 in the composite structure 220 is a silver nanowire layer, the etching solution can be selected to have a composition that can etch silver, e.g., the main composition of the etching solution can be H₃PO₄(ratio of about 55% to about 70%) and HNO₃(in a ratio of about 5% to about 15%) to remove the silver metal material in the same process. In other embodiments, the main component of the etching solution may be ferric chloride/nitric acid or phosphoric acid/hydrogen peroxide.

Next, referring to fig. 3D, a modification step is performed to form a metal nanowire layer 120 composed of a plurality of modified metal nanowires 122 in the peripheral region PA and the display region VA located in the non-folding region NR. The modifying step may cover the display area VA in the folding area BR with a photoresist, a peelable glue, or a similar material layer to shield the metal nanowire layer 120 in the display area VA in the folding area BR, so that the modifying step is performed only on the metal nanowire layer 120 in the peripheral area PA and the non-folding area NR. In detail, after the modification step, at least a portion of the metal nanowires 122 in the metal nanowire layer 120 in the peripheral region PA and the non-folding region NR is modified to form a coating structure 140 on the surface thereof, thereby forming the modified metal nanowires 122. In some embodiments, the coating structure 140 may be formed by electroless plating, i.e., by penetrating an electroless plating solution into the pre-cured or incompletely cured film 130, reactive metal ions in the electroless plating solution are deposited on the surface of the metal nanowire 122 through a redox reaction to form the coating structure 140. The coating structure 140 can be a layer structure, an island-shaped protrusion structure, a dot-shaped protrusion structure or a combination thereof made of conductive material; alternatively, the covering structure 140 may be a single-layer or multi-layer structure made of a single material or multiple materials; alternatively, the coating structure 140 may be a single layer or a multi-layer structure made of alloy-state material.

It should be noted that, since the modification step is performed along the surface of the metal nanowire 122, the type of the coating structure 140 is substantially grown according to the type of the metal nanowire 122. In the modification step, the growth conditions (e.g., the electroless plating time and/or the concentration of the electroless plating solution components) of the coating structure 140 may be controlled such that the coating structure 140 is coated on the surface of the metal nanowires 122 without overgrowth. In addition, as mentioned above, the pre-cured or incompletely cured film 130 can also serve as a position-limiting and controlling function. As such, the coating structure 140 formed by the modification step is not separately precipitated/grown in the film 130 without contacting the metal nanowire 122, and is formed between the surface of the metal nanowire 122 and the film 130. In some embodiments, the film layer 130 is still filled between adjacent metal nanowires 122. On the other hand, the coating structure 140 formed by the electroless plating/electrolytic plating has a high density, and compared with the size of the thin line L of the peripheral lead 150 and the touch sensing electrode 170 (for example, about 10 μm line width), the defect size of the coating structure 140 is about 0.01 to about 0.001 times of the size of the thin line L of the peripheral lead 150 and the touch sensing electrode 170, so even if the coating structure 140 has a defect, the problem of wire breakage of the peripheral lead 150 and the touch sensing electrode 170 is not caused. In some embodiments, a curing step may be further included after the modifying step to bring the pre-cured or incompletely cured film layer 130 to a fully cured state.

After the above steps, the touch panel 100 shown in fig. 2A can be formed. In summary, the peripheral lead 150 located in the peripheral area PA may at least include the metal nanowire layer 120 formed by the modified metal nanowires 122, and the touch sensing electrode 170 located in the non-folding area NR may also at least include the metal nanowire layer 120 formed by the modified metal nanowires 122, that is, the peripheral lead 150 and the metal nanowires 122 located in the touch sensing electrode 170 of the non-folding area NR are both covered with the covering structure 140, wherein the covering structure 140 may have the same or similar structural appearance as the metal nanowires 122, and the film layer 130 is filled between the adjacent metal nanowires 122.

Please refer back to fig. 2A and fig. 2B. In some embodiments, the non-conductive region 180 may be disposed between adjacent peripheral wires 150 in the peripheral area PA and between adjacent touch sensing electrodes 170 in the display area VA to electrically isolate the adjacent peripheral wires 150 and the adjacent touch sensing electrodes 170. In some embodiments, the non-conductive region 180 may be a gap. In some embodiments, the above-mentioned etching method can be used to form the gaps between the peripheral wires 150 and between the touch sensing electrodes 170.

In some embodiments, the touch panel may further include a protective layer. Specifically, please refer to fig. 4, which illustrates a cross-sectional view of a touch panel 100a according to another embodiment of the present disclosure, wherein the cross-sectional position is the same as the cross-sectional position of fig. 2B. The touch panel 100a includes a protection layer 190, and the material of the protection layer 190 may refer to the material of the film layer 130 described above. In some embodiments, the protection layer 190 covers the touch panel 100 entirely, that is, the protection layer 190 covers the peripheral wires 150 and the touch sensing electrodes 170. The protective layer 190 may also fill the non-conductive region 180 between the adjacent peripheral wires 150 to electrically isolate the adjacent peripheral wires 150; or the protection layer 190 may fill in the non-conductive region 180 between the adjacent touch sensing electrodes 170 to electrically isolate the adjacent touch sensing electrodes 170.

Fig. 5A is a schematic top view illustrating a touch panel 100b according to some other embodiments of the present disclosure. Fig. 5B is a cross-sectional view of the touch panel 100B of fig. 5A taken along the line 5B-5B according to some embodiments of the present disclosure. Referring to fig. 5A and 5B, the touch panel 100B is a double-sided single-layer type touch panel 100B, and for clarity and convenience of description, in the embodiment of fig. 5A and 5B, the first touch sensing electrode 172 and the second touch sensing electrode 174 are used to describe the configuration of the touch sensing electrodes. The first touch sensing electrode 172 is disposed on a first surface (e.g., an upper surface) of the substrate 110, and the second touch sensing electrode 174 is disposed on a second surface (e.g., a lower surface) of the substrate 110, such that the first touch sensing electrode 172 and the second touch sensing electrode 174 are electrically insulated from each other. In some embodiments, the first touch sensing electrodes 172 are a plurality of strip electrodes extending along the second direction D2, and the plurality of strip electrodes may be arranged equidistantly along the first direction D1, and the second touch sensing electrodes 174 are a plurality of strip electrodes extending along the first direction D1, and the plurality of strip electrodes may be arranged equidistantly along the second direction D2, wherein the first direction D1 and the second direction D2 are perpendicular to each other. In other words, the first touch sensing electrodes 172 and the second touch sensing electrodes 174 have different extending directions and are staggered with each other. The first touch sensing electrode 172 and the second touch sensing electrode 174 can transmit a control signal and receive a touch sensing signal, respectively. As such, the touch position can be obtained by detecting a signal change (e.g., a capacitance change) between the first touch sensing electrode 172 and the second touch sensing electrode 174.

In some embodiments, the first touch sensing electrode 172 and the second touch sensing electrode 174 each have a grid-like pattern formed by interlacing a plurality of thin lines L, and each include a metal nanowire layer 120 formed by modified metal nanowires 122. As described above, the modified and unmodified metal nanowires 122 and the film layer 130 applied to the modified and unmodified metal nanowires 122 are patterned to form a grid pattern formed by interlacing a plurality of thin lines L, and the grid pattern is the electrode pattern of the first touch sensing electrode 172 and the second touch sensing electrode 174. In some embodiments, the thin line L in the first touch sensing electrode 172 and the thin line L in the second touch sensing electrode 174 do not completely overlap each other. Specifically, when viewed from a top view angle (i.e., the viewing angle of fig. 5A), the intersection of two thin lines L in the second touch sensing electrode 174 may be located at the very center of the grid formed by the thin lines L in the first touch sensing electrode 172; in contrast, the intersection of the two thin lines L in the first touch sensing electrode 172 may be located at the center of the grid formed by the thin lines L in the second touch sensing electrode 174. However, the disclosure is not limited thereto, and in other embodiments, the thin line L in the first touch sensing electrode 172 and the thin line L in the second touch sensing electrode 174 may also completely overlap. The first touch sensing electrode 172 is electrically connected to the corresponding peripheral lead 150, and the second touch sensing electrode 174 is also electrically connected to the corresponding peripheral lead 150. As in the previous embodiments, the peripheral lead 150, the first touch sensing electrode 172 located in the non-folding region NR, and the second touch sensing electrode 174 located in the non-folding region NR all include the modified metal nanowire 122 and the film layer 130; the first touch sensing electrode 172 located in the folding region BR and the second touch sensing electrode 174 located in the folding region BR both include the unmodified metal nanowire 122 and the film layer 130. In other words, the peripheral lead 150, the first touch sensing electrode 172 located in the non-folding region NR, and the second touch sensing electrode 174 located in the non-folding region NR can be formed by forming the coating structure 140 on the surface of the metal nanowire 122 according to the aforementioned method. On the other hand, the line width W1 and the line distance X1 of the thin line L in the first touch sensing electrode 172 and the second touch sensing electrode 174, and the line width W2 and the line distance X2 of the peripheral lead 150 can refer to the foregoing description, and are not repeated herein.

The method for manufacturing the double-sided single-layer type touch panel 100B illustrated in fig. 5A and 5B includes steps S30 to S36. In step S30, the substrate 110 having the predefined peripheral region PA and display region VA and the predefined folding region BR and non-folding region NR is provided, and the unmodified metal nanowires 122 are disposed on two opposite surfaces of the substrate 110, so as to form the metal nanowire layer 120 on the peripheral region PA and the display region VA (including the regions located in the folding region BR and the non-folding region NR) on the two opposite surfaces of the substrate 110, respectively. In step S32, the film 130 is disposed on the unmodified metal nanowires 122, such that the film 130 covers the unmodified metal nanowires 122 on two opposite surfaces of the substrate 110, and the film 130 is in a pre-cured or incompletely cured state. In step S34, a double-sided patterning step is performed to form a patterned metal nanowire layer 120, wherein the metal nanowire layer 120 in the peripheral area PA on two opposite surfaces of the substrate 110 is patterned to form the peripheral wires 150, and the metal nanowire layer 120 in the display area VA (including the areas in the folding area BR and the non-folding area NR) on two opposite surfaces of the substrate 110 is patterned to form the touch sensing electrode 170. In step S36, a double-sided modification step is performed to mold the coating structures 140 on the metal nanowires 122 of the portions of the two opposite surfaces of the substrate 110, such that the peripheral leads 150 of the peripheral area PA and the touch sensing electrodes 170 of the non-folding area NR on the two opposite surfaces of the substrate 110 are formed by the modified metal nanowires 122, and the touch sensing electrodes 170 of the folding area BR are formed by the metal nanowires 122 before modification. It should be understood that the manufacturing method of the double-sided single-layer type touch panel 100b can refer to the manufacturing method of the single-sided type touch panel 100 described above, and thus, the description thereof is omitted.

The method for modifying metal nanowires of the present disclosure can also be applied to the fabrication of sensing electrodes without considering transmittance, such as but not limited to touch pads of notebook computers, antenna structures, and wireless charging coils. In some embodiments, the sensing electrode can be connected to the trace, and further connected to an external circuit to transmit signals. In some embodiments, the traces may correspond to the peripheral leads described above and are also formed by modified metal nanowires.

The touch panel disclosed by the invention can be assembled with other electronic devices, such as a display with a touch function. For example, the substrate may be attached to a display device (e.g., a liquid crystal display device or an organic light emitting diode display device), and the substrate and the display device may be attached by using an optical adhesive or other adhesives, and the touch sensing electrode may also be attached to an outer cover layer (e.g., a protective glass) by using an optical adhesive. The touch panel and the antenna can be applied to electronic equipment such as a portable phone, a tablet computer, a notebook computer and the like, and can also be applied to flexible products. The touch panel disclosed by the invention can also be applied to a polarizer. The electrode of the present disclosure may be applied to wearable devices (e.g., watches, glasses, smart clothes, smart shoes, etc.) and automotive devices (e.g., instrument panels, event recorders, automotive rearview mirrors, windows, etc.).

According to the above-mentioned embodiments of the present disclosure, in the touch panel of the present disclosure, the peripheral leads located in the peripheral region and the touch sensing electrodes located in the display region are formed by the modified metal nanowires, so that the sheet resistance of the touch panel can be effectively reduced to improve the conductivity of the touch panel, and the rc loading value of the touch panel can be reduced. Moreover, the coating structure is not present in the display area of the folding area, so that the flexibility of the touch panel can be well maintained. On the other hand, because the touch sensing electrode positioned in the display area has a grid pattern formed by interlacing a plurality of thin lines, the light transmittance of the display area can be prevented from being influenced by the modified metal nano-wires, and the display area of the touch panel has good optical characteristics. In addition, in the manufacturing process of the touch panel, the peripheral lead and the touch sensing electrode can be manufactured through the steps of deposition and patterning in the same manufacturing process, so that the overlapping step and the overlapping tolerance can be omitted, the width of the peripheral area of the touch panel is further reduced, and the requirement of a narrow frame of a display is met.

Although the present disclosure has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure, and therefore the scope of the present disclosure should be limited only by the terms of the appended claims.

Claims

1. A touch panel, comprising:

a substrate having a display region and a peripheral region, and having a folding region and a non-folding region;

a peripheral lead disposed in the peripheral region of the substrate; and

a first touch sensing electrode disposed in the display region of the substrate and having a first portion located in the folding region and a second portion located in the non-folding region, wherein the first touch sensing electrode is electrically connected to the peripheral lead and has a grid pattern formed by interlacing a plurality of first thin lines,

the peripheral lead and the first touch sensing electrode respectively comprise a plurality of conductive nanostructures and a film layer additionally arranged on each conductive nanostructure, and an interface between each conductive nanostructure and the film layer in the second part of the peripheral lead and the first touch sensing electrode is provided with a coating structure.

2. The touch panel of claim 1, wherein the coating structure comprises a plating layer, and the plating layer completely covers the interface between each of the conductive nanostructures and the film layer.

3. The touch panel of claim 1, wherein the film is filled between adjacent conductive nanostructures, and the film does not have the coating structure existing alone.

4. The touch panel of claim 1, wherein each of the conductive nanostructures comprises a metal nanowire, and the coating structure completely covers an interface between the metal nanowire and the film layer, and forms a uniform coating layer on the interface between the metal nanowire and the film layer.

5. The touch panel of claim 1, wherein the coating structure is a layer structure made of a conductive material, an island-like protrusion structure, a dot-like protrusion structure, or a combination thereof.

6. The touch panel of claim 5, wherein the coating structure is a silver coating structure, a gold coating structure, a copper coating structure, a nickel coating structure, a platinum coating structure, an iridium coating structure, a rhodium coating structure, a palladium coating structure, an osmium coating structure, or an alloy coating structure of combinations thereof.

7. The touch panel of claim 1, wherein the coating structure is a single layer structure made of a single metal material or an alloy material, or a two-layer or multi-layer structure made of two or more metal materials or alloys.

8. The touch panel of claim 1, wherein the coating structure is a chemical copper plating layer, an electroplated copper layer, a chemical copper nickel plating layer, a chemical copper silver plating layer, or a combination thereof.

9. The touch panel of claim 1, wherein each of the conductive nanostructures and the film layer are located in each of the first thin lines.

10. The touch panel of claim 1, wherein each of the conductive nanostructures, the film layer and the coating structure is located in each of the first thin lines of the second portion of the first touch sensing electrode.

11. The touch panel of claim 1, wherein a boundary is formed between the folding region and the non-folding region, and a line width of each of the first thin lines crossing the boundary gradually increases from a distance from the boundary to a distance close to the boundary.

12. The touch panel of claim 11, wherein each of the first thin lines crossing the boundary has a first portion far from the boundary and a second portion near the boundary, the line width of the first portion is between 1 micron and 5 microns, and the line width of the second portion is between 5 microns and 30 microns.

13. The touch panel of claim 1, wherein a boundary is located between the display region and the peripheral region of the folding region, and a line width of each of the first thin lines adjacent to the boundary gradually increases from a distance from the boundary to a distance close to the boundary.

14. The touch panel of claim 13, wherein each of the first thin lines adjacent to the boundary has a first portion far from the boundary and a second portion near the boundary, the line width of the first portion is between 1 micron and 5 microns, and the line width of the second portion is between 5 microns and 30 microns.

15. The touch panel of claim 1, wherein the substrate has a first surface and a second surface opposite to each other, the first touch sensing electrode is disposed on the first surface of the substrate, and the touch panel further comprises:

and the second touch sensing electrode is arranged on the second surface of the substrate and the display area, and is provided with a grid pattern formed by interlacing a plurality of second thin lines.

16. The touch panel of claim 15, wherein the second touch sensing electrode has a first portion located in the folding region and a second portion located in the non-folding region, the second touch sensing electrode comprises the plurality of conductive nanostructures and the film layer applied to each of the conductive nanostructures, and an interface between each of the conductive nanostructures and the film layer in the second portion of the second touch sensing electrode has the coating structure.

17. The touch panel according to claim 15, wherein a grid pattern in which the first thin lines are interlaced does not completely overlap a grid pattern in which the second thin lines are interlaced.

18. A method for manufacturing a touch panel is characterized by comprising the following steps:

providing a substrate having a display area and a peripheral area, and having a folding area and a non-folding area;

arranging a plurality of conductive nanostructures in the display area and the peripheral area to form a conductive layer;

additionally arranging a film layer on the conducting layer, and enabling the film layer to reach a pre-curing state or an incomplete curing state;

performing a patterning step comprising:

patterning the conductive layer and the film layer in the display region of the folding region and the non-folding region to form a touch sensing electrode with a grid pattern formed by interlacing a plurality of thin lines; and

patterning the conductive layer and the film layer in the peripheral area to form a peripheral lead; and

and performing a modification step to form a coating structure on a surface of each of the conductive nanostructures in the peripheral lead and the touch sensing electrode in the non-folding region, so that an interface between each of the conductive nanostructures in the peripheral lead and the touch sensing electrode in the non-folding region and the film layer substantially has the coating structure.

19. The method of claim 18, wherein the patterning step is performed before the modifying step.

20. The method as claimed in claim 18, wherein the patterning of the conductive layer and the film layer in the display area and the peripheral area is performed in a same process.

21. The method of claim 18, further comprising masking the display region in the folding region before the modifying step.

22. The method for manufacturing a touch panel according to claim 18, wherein the modifying step comprises:

immersing the film layer and the plurality of conductive nanostructures in a chemical plating solution, wherein the chemical plating solution penetrates into the film layer and contacts the plurality of conductive nanostructures, so that a metal is precipitated on the surface of each conductive nanostructure.

23. The method as claimed in claim 22, wherein the coating structure is formed along the surface of each of the conductive nanostructures and located at the interface between each of the conductive nanostructures and the film layer.

24. The method as claimed in claim 18, wherein the step of applying the film layer on the conductive layer comprises:

coating a polymer on the conductive layer; and

the curing conditions are controlled so that the polymer reaches a pre-cured or incompletely cured state.

25. The method as claimed in claim 18, wherein the step of applying the film layer on the conductive layer comprises:

coating a polymer on the conductive layer; and

controlling the curing condition to enable the polymer to reach a pre-curing state or an incomplete curing state, wherein the film layer in the pre-curing state or the incomplete curing state is provided with a first layer area and a second layer area, and the curing state of the second layer area is higher than that of the first layer area.

26. The method as claimed in claim 25, wherein in the first layer region, the coating structure is formed along the surface of each of the conductive nanostructures and located at the interface between each of the conductive nanostructures and the film layer.

27. The method of claim 25, wherein the controlling the curing conditions comprises:

introducing a gas and controlling the respective concentrations of the gas in the first layer region and the second layer region.

28. The method of claim 18, wherein the modifying step comprises an electroless plating step, an electroplating step, or a combination thereof.

29. A touch device comprising the touch panel according to claim 1.

30. The touch device of claim 29, wherein the touch device comprises a display, a portable phone, a tablet computer, a wearable device, a car device, a notebook computer, or a polarizer.