CN115113749A

CN115113749A - Touch sensor and manufacturing method thereof

Info

Publication number: CN115113749A
Application number: CN202110286091.XA
Authority: CN
Inventors: 甘艺鹏; 郑江山; 刘康宇; 郭小萍
Original assignee: TPK Advanced Solutions Inc
Current assignee: TPK Advanced Solutions Inc
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2022-09-27
Also published as: JP2022145455A; KR20220129981A; KR102552535B1

Abstract

A touch sensor and a manufacturing method thereof are provided, the touch sensor is provided with a visible area and a peripheral area arranged on at least one side of the visible area, and comprises a substrate, a metal nanowire layer and a metal layer. The metal nanowire layer is arranged on the substrate and is provided with a first part corresponding to the visible area and a second part corresponding to the peripheral area. The metal layer is arranged on the substrate and correspondingly positioned in the peripheral area, wherein part of the metal layer is stacked and contacted with at least part of the second part of the metal nanowire layer to form a lap joint area, and the lap joint area of the lap joint area is 0.09mm ² To 1.20mm ² And the lap joint resistance of the lap joint area is less than 50 omega. The touch sensor disclosed by the invention not only can have the size of a narrow frame determined in the industry, but also can have a required overlap resistance value.

Description

Touch sensor and manufacturing method thereof

Technical Field

The present disclosure relates to a touch sensor and a method for manufacturing the touch sensor.

Background

In recent years, portable electronic products such as mobile phones, notebook computers, satellite navigation systems, and digital video players have widely used touch sensors as information communication channels between users and the electronic products.

With the increasing market demand for narrow-bezel electronic products, manufacturers are not dedicated to reducing the bezel size of the electronic products to meet the user's demand, and, in contrast, for touch sensors, the size of the peripheral area needs to be reduced. Generally, a touch sensor includes a touch electrode and a peripheral circuit, and the touch electrode and the peripheral circuit are usually overlapped with each other in a peripheral area to form a conductive path or a loop, and factors affecting the size of the peripheral area of the touch sensor generally include an overlapping tolerance between the touch electrode and the peripheral circuit, an overlapping area between the touch electrode and the peripheral circuit, a line width and a line distance of the peripheral circuit itself, and the like. When the size of the peripheral area is reduced by reducing the overlapping area, the overlapping impedance value between the touch electrode and the peripheral circuit increases along with the reduction of the overlapping area, thereby generating a plurality of adverse effects on the signal transmission of the touch sensor. In summary, it is a current research direction to provide a touch sensor that can not only meet the design of narrow frame size identified in the industry, but also meet the requirement of the overlap resistance value.

Disclosure of Invention

According to some embodiments of the present disclosure, a touch sensor has a visible region and a peripheral region disposed on at least one side of the visible region, and includes a substrate, a metal nanowire layer, and a metal layer. The metal nanowire layer is arranged on the substrate and is provided with a first part corresponding to the visible area and a second part corresponding to the peripheral area. The metal layer is arranged on the substrate and correspondingly positioned in the peripheral region, part of the metal layer is stacked and contacted with at least part of the second part of the metal nanowire layer to form a lap joint region, and the lap joint area of the lap joint region is 0.09mm ² To 1.20mm ² And the lap joint resistance of the lap joint area is less than 50 omega.

In some embodiments of the present disclosure, the area of the lap joint is a vertical projection area of the lap joint region on the substrate.

In some embodiments of the present disclosure, the overlapping area is between 0.09mm ² To 0.60mm ² In between.

In some embodiments of the present disclosure, the overlap resistance is less than 40 Ω, less than 30 Ω, less than 20 Ω, or less than 10 Ω.

In some embodiments of the present disclosure, the metal nanowire layer includes a matrix, a plurality of first metal nanowires and a plurality of second metal nanowires, the first metal nanowires are completely located in the matrix, and the second metal nanowires are only partially embedded in the matrix.

In some embodiments of the present disclosure, the second metal nanowire in the second portion of the metal nanowire layer has a first portion embedded in the matrix and a second portion protruding from the upper surface of the matrix, and the second portion of the second metal nanowire is embedded in the metal layer.

In some embodiments of the present disclosure, the second metal nanowire has a first portion embedded in the matrix and a second portion protruding from the upper surface of the matrix.

In some embodiments of the present disclosure, the metal nanowire layer further includes a plurality of first film structures and a plurality of second film structures. The first film structure is located at an interface of the first metal nanowire and the substrate, and the second film structure is located at an interface of the first portion of the second metal nanowire and the substrate.

In some embodiments of the present disclosure, the first film structure covers the first metal nanowire to form a first covering structure. The second film structure wraps the first part of the second metal nanowire to form a second coating structure.

In some embodiments of the present disclosure, the material of the first film structure and the second film structure includes a polyethylene derivative.

In some embodiments of the present disclosure, the material of the metal layer includes photosensitive silver.

In some embodiments of the present disclosure, the first portion of the metal nanowire layer constitutes a touch sensing electrode, and a portion of the metal layer constitutes a peripheral circuit.

According to other embodiments of the present disclosure, a touch sensor has a visible displayThe area and the peripheral area arranged on at least one side of the visible area, and the manufacturing method of the touch sensor comprises the following steps: providing a substrate; forming a metal nanowire layer on the substrate and correspondingly positioned in the visible area and the peripheral area; carrying out surface treatment on the metal nanowire layer; and forming a metal layer on the substrate and corresponding to the peripheral region, wherein part of the metal layer is stacked and contacted with the surface-treated metal nanowire layer to form a lap joint region, and the lap joint area of the lap joint region is 0.09mm ² To 1.20mm ² And the lap joint resistance of the lap joint area is less than 50 omega.

In some embodiments of the present disclosure, the surface treating the metal nanowire layer comprises: performing a vacuum plasma process on the metal nanowire layer, wherein the vacuum plasma process uses argon plasma with a power of 2kW to 8kW and a flow rate of 1500sccm to 2500sccm, and the time of the vacuum plasma process is between 20 minutes and 30 minutes.

In some embodiments of the present disclosure, the metal nanowire layer may include a substrate, a plurality of metal nanowires having a first portion embedded in the substrate and a second portion protruding from an upper surface of the substrate, and a plurality of film structures covering the metal nanowires. The surface treatment of the metal nanowire layer includes: and removing the film structure covering the second part of the metal nanowire to expose the second part of the metal nanowire.

In some embodiments of the present disclosure, the metal nanowire layer includes a substrate, a plurality of metal nanowires, and a plurality of film structures, and the film structures are distributed on and in the substrate. The surface treatment of the metal nanowire layer includes: and removing the film structure distributed on the upper surface of the substrate to expose the upper surface of the substrate.

In some embodiments of the present disclosure, the surface-treated metal nanowire layer includes a matrix and a plurality of metal nanowires, wherein the metal nanowires have a first portion embedded in the matrix and a second portion protruding from an upper surface of the matrix. The metal layer is formed corresponding to the peripheral region such that the second portion of the metal nanowire located in the peripheral region is embedded in the metal layer.

In some embodiments of the present disclosure, the step of forming the metal nanowire layer on the substrate includes: and patterning the metal nanowire layer to form a touch sensing electrode.

In some embodiments of the present disclosure, the step of forming the metal layer on the substrate includes: the metal layer is patterned to form a peripheral circuit.

According to the above-mentioned embodiments of the present disclosure, the touch sensor of the present disclosure has a bonding region formed by bonding a portion of the metal nanowire layer and a portion of the metal layer in the peripheral region. The metal nanowire layer can be subjected to appropriate surface treatment, so that a lap joint area formed by the metal layer and the metal nanowire layer can provide a good lap joint effect within a required lap joint area range. Therefore, the touch sensor disclosed by the invention not only can have the narrow frame size determined in the industry, but also can have the required lap joint resistance value.

Drawings

These and other objects, features, advantages and embodiments of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

fig. 1A to 1E are schematic cross-sectional views illustrating a surface treatment method of a metal nanowire layer at different steps according to some embodiments of the present disclosure;

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

FIG. 2B is a schematic cross-sectional view of the touch sensor of FIG. 2A taken along line 2B-2B;

FIG. 2C is a schematic diagram showing a partial enlarged view of a region R of the touch sensor shown in FIG. 2B; and

FIG. 3 is a schematic diagram illustrating the measurement of the bonding resistance of the bonding region according to some embodiments of the present disclosure.

[ notation ] to show

10 dispersion liquid

11 at the liquid level

100 touch sensor

110 base plate

111: surface

120 metal nanowire layer

121 upper surface

122 metal nanowires

122A first metal nanowire

122B second metal nanowires

122a first part

122b second part

124 matrix

125 upper surface of

126 film structure (film layer, coating structure)

126A first film Structure

126B second film Structure

126C third Membrane Structure

130 metal layer

VA visual zone

PA peripheral area

AP argon plasma

TE touch induction electrode

L1 electrode wire

T is peripheral circuit

A is a lap zone

L1 length

W1 width

R is a region

X, Y, Z, W

2B-2B 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, some conventional structures and elements are shown in simplified schematic form in the drawings. In addition, the dimensions of the various elements in the drawings are not necessarily to scale, for the convenience of the reader.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a "first element," "component," "region," "layer" or "portion" described below could also be termed a second element, component, region, layer or portion without departing from the teachings herein.

It will be understood that 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 in the figures. 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 one of the figures is 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 "lower" or "beneath" may include both an orientation of above and below.

The present disclosure provides a touch sensor having a narrow frame size as defined in the art and meeting the requirement of a lap resistance value, which includes a method of surface-treating a metal nanowire layer (i.e., a layer including metal nanowires), and a touch sensor fabricated by using the metal nanowire layer after surface-treatment. It is to be appreciated that for clarity and ease of description, the surface treatment method for the metal nanowire layer will be described first herein.

Fig. 1A to 1E are schematic cross-sectional views illustrating surface treatment methods of a metal nanowire layer 120 at different steps according to some embodiments of the present disclosure. Please refer to fig. 1A. First, a dispersion liquid 10 is provided. In some embodiments, the dispersion 10 may be formed by, for example, mixing a solvent, a filler, and the metal nanowires 122, wherein the filler and the solvent are uniformly mixed, and the metal nanowires 122 are dispersed in the mixed filler and solvent. In some embodiments, the solvent may be water, alcohols, ketones, ethers, hydrocarbons, aromatic solvents (e.g., benzene, toluene, xylene, or the like), or combinations thereof. In some embodiments, the filler may include an insulating material. For example, the insulating material may include a non-conductive resin or other organic material such as, but not limited to, polyacrylate, epoxy, polyurethane, polysilane, polysiloxane, polyethylene, polypropylene, polycarbonate, polyvinyl butyral, poly (silicon-acrylic), poly (styrene sulfonic acid), acrylonitrile-butadiene-styrene copolymer, poly (3, 4-ethylenedioxythiophene), a ceramic material, or a combination thereof. In some embodiments, the metal nanowires 122 can be, for example, but not limited to, nano silver wires, nano gold wires, nano copper wires, nano nickel wires, or a combination thereof.

It should be understood that "metal nanowires" 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 dispersion 10 may include a polymer binder to improve the compatibility between the metal nanowires 122 and the solvent and the filler and the stability of the metal nanowires 122 in the solvent and the filler, so that the metal nanowires 122 can be uniformly dispersed in the solvent and the filler. In some embodiments, the polymeric binder may include a polyethylene derivative, such as polyvinylpyrrolidone (PVP). In some embodiments, the dispersion 10 may further include additives and/or surfactants. Specifically, the additive and/or surfactant may be, for example, carboxymethyl cellulose, hydroxyethyl cellulose, hypromellose, sulfosuccinate sulfonate, sulfate, phosphate, fluorosurfactant, disulfonate, or a combination thereof.

Please refer to fig. 1B. Next, a substrate 110 is provided, and the dispersion 10 containing the metal nanowires 122 is coated on the surface 111 of the substrate 110. If observed on a microscopic scale, the metal nanowires 122 are randomly distributed in the dispersion liquid 10 without directionality, and a part of the metal nanowires 122 are distributed near the liquid surface 11 of the dispersion liquid 10, so that the liquid surface 11 of the dispersion liquid 10 is uneven and wavy. In some embodiments, the metal nanowires 122 in the dispersion 10 can contact each other to provide a continuous current path, thereby forming 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, one silver nanowire and another silver nanowire form a direct contact state (i.e., a silver-silver contact interface) at the crossing position to form an electron transfer path with low resistance. On the other hand, the dispersion 10 applied on the surface 111 of the substrate 110 can completely cover each of the metal nanowires 122, and the solvent and the filler in the dispersion 10 are uniformly mixed during and after the application without generating aggregates or precipitates.

Please refer to fig. 1C. Subsequently, a curing/drying step is performed to completely cure the dispersion liquid 10 applied to the surface 111 of the substrate 110 using light, heat, or other means, thereby forming the metal nanowire layer 120. In detail, after the curing/drying step, the solvent in the dispersion 10 is volatilized, and the filler is cured to form the matrix 124, and the metal nanowires 122 may be distributed in the matrix 124 in a random manner. In some embodiments, the polymeric binder in the dispersion 10 also cures to form the film structure 126 in the metal nanowire layer 120. In more detail, since a part of the polymer binder may exist in the inside of the whole of the dispersion 10 and a part of the polymer binder may exist at an upper layer of the whole of the dispersion 10 before the curing/drying step, a part of the film structure 126 may be formed in the inside of the matrix 124 and a part of the film structure 126 may be formed on the upper surface 125 of the matrix 124 after the curing/drying step. In some embodiments, the membrane structures 126 located on the interior of the substrate 124 may be distributed in the substrate 124 in a random manner, for example, and the membrane structures 126 located on the upper surface 125 of the substrate 124 may cover the entire upper surface 125 of the substrate 124 to form a membrane layer 126, for example.

In some embodiments, the polymeric binder present in the interior of the dispersion 10 as a whole may also be further cured along the surface of the metal nanowires 122 during the curing/drying step. As such, after the curing/drying step, portions of the film structure 126 may be formed at the interface of the metal nanowires 122 and the matrix 124, while portions of the film structure 126 may be separately present in the matrix 124 between adjacent metal nanowires 122. In some embodiments, the film structure 126 may encapsulate each of the metal nanowires 122 to form the coating structure 126. In some embodiments, the coating structure 126 may cover a portion of the surface of each metal nanowire 122. In other embodiments, the coating structure 126 may cover the entire surface of each metal nanowire 122. More specifically, the coating rate of the coating structure 126 may account for more than 80%, 90% to 95%, 90% to 99%, or 90% to 100% of the total surface area of the metal nanowires 122. It should be understood that when the coating rate of the coating structure 126 is 100%, it means that the surface of the metal nanowire 122 is not exposed at all. It should be noted that, since the metal nanowires 122 of the present disclosure can contact each other to form a conductive network, the coating structure 126 is substantially continuously formed on the entire surface of the metal nanowires 122 contacting each other to cover the entire conductive network, and the contact state between the metal nanowires 122 is not affected. In some embodiments, the coating structure 126 may, for example, conformally coat the surface of each metal nanowire 122.

For the metal nanowires 122 located near the upper surface 121 of the metal nanowire layer 120, each metal nanowire 122 has a first portion 122a embedded in the matrix 124 and a second portion 122b protruding from the upper surface 125 of the matrix 124, and the surface of each metal nanowire 122 is covered by the covering structure 126. In other words, the coating structure 126 covering the first portion 122a of the metal nanowire 122 is located at the interface between the substrate 124 and the metal nanowire 122 (i.e., the coating structure 126 is spaced between the substrate 124 and the first portion 122a of the metal nanowire 122), and the coating structure 126 covering the second portion 122b of the metal nanowire 122 is exposed outside the substrate 124. If viewed as the metal nanowire layer 120 as a whole, the metal nanowire layer 120 may include a substrate 124, metal nanowires 122, and a film structure 126. The film structure 126 may be present inside the substrate 124 alone, or cover the upper surface 125 of the substrate 124 to form a film layer 126, or coat each of the metal nanowires 122 to form a coating structure 126, and the material of the film structure 126 may include a polyvinyl derivative, such as polyvinylpyrrolidone.

Please refer to fig. 1D. Subsequently, the cured/dried metal nanowire layer 120 may be subjected to a surface treatment. The surface-treated metal nanowire layer 120 may have a low surface resistance, and thus may be stably electrically connected to other subsequently formed conductive layers (e.g., a metal layer, the specific structure of which will be described in detail below). For example, after the metal nanowire layer 120 is formed, a vacuum plasma process may be performed on the metal nanowire layer 120 to remove the film structure (film layer) 126 on the upper surface 125 of the substrate 124 and the film structure (coating structure) 126 covering the second portion 122b of the metal nanowire 122, so that the upper surface 125 of the substrate 124 and the second portion 122b of the metal nanowire 122 are exposed. In some embodiments, the vacuum plasma process is performed by using argon plasma AP to perform a surface treatment on the metal nanowire layer 120 for 20 minutes to 30 minutes at a power of 2kW to 8kW and a flow rate of 1500sccm to 2500sccm (preferably 1900sccm to 2100 sccm). The surface-treated metal nanowire layer 120 is shown in fig. 1E, in which the film structure (film layer) 126 on the upper surface 125 of the substrate 124 and the film structure (coating structure) 126 covering the second portion 122b of the metal nanowires 122 are removed, so as to leave the film structure 126 in the substrate 124 (including the film structure (coating structure) 126 covering the metal nanowires 122 and the film structure 126 existing in the substrate 124 alone). Since the second portion 122b of the metal nanowire 122 near the upper surface 125 of the substrate 124 is completely exposed without being covered by the film structure 126 after the surface treatment, the surface-treated metal nanowire layer 120 may have a lower surface resistance, which may be reduced by about 5% to about 10% compared to the surface resistance of the metal nanowire layer 120 without the surface treatment. As a result, the metal nanowire layer 120 has a low bonding resistance when being bonded to other conductive layers formed subsequently.

The method disclosed by the invention can be applied to manufacturing the touch sensor. Specifically, please refer to fig. 2A and 2B, wherein fig. 2A is a schematic top view of the touch sensor 100 according to some embodiments of the present disclosure, and fig. 2B is a schematic cross-sectional view of the touch sensor 100 of fig. 2A along a line 2B-2B. In some embodiments, the touch sensor 100 can include a substrate 110, a metal nanowire layer 120, and a metal layer 130. The substrate 110 is configured to support the metal nanowire layer 120 and the metal layer 130, 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, the touch sensor 100 has a visible area VA and a peripheral area PA disposed at a side of the visible area VA. For example, the peripheral region PA may be a frame-shaped region disposed around the visible area VA (e.g., covering right, left, upper, and lower sides). For example, the peripheral area PA may also be an L-shaped area disposed on the left and lower sides of the visible area VA.

In some embodiments, the metal nanowire layers 120 and the metal layers 130 are sequentially disposed on the substrate 110, and in the peripheral region PA, a portion of the metal layers 130 are stacked and contact a portion of the metal nanowire layers 120 to form a lap joint region a. More specifically, the metal nanowire layer 120 has a first portion 120a located in the visible area VA and a second portion 120b located in the peripheral area PA, the first portion 120a of the metal nanowire layer 120 constitutes the touch sensing electrode TE, and at least a portion of the second portion 120b of the metal nanowire layer 120 partially overlaps and contacts the metal layer 130 located in the peripheral area PA and constituting the peripheral circuit T to form the overlap area a. Through the overlapping between the metal layer 130 and the metal nanowire layer 120, the touch sensor 100 can form an electron transmission path crossing the visible region VA and the peripheral region PA for transmitting touch or other signals. It should be noted that the metal nanowire layer 120 and the metal layer 130 of the present disclosure are merely used for convenience to illustrate the relationship of the stacked structure, in fact, the metal nanowire layer 120 may be patterned to include at least one touch sensing electrode TE, the metal layer 130 may be patterned to include at least one peripheral circuit T corresponding to the touch sensing electrode TE, and the bonding area a of the present disclosure refers to an area where one peripheral circuit T and one touch sensing electrode TE are in contact with each other.

In some embodiments, one touch sensing electrode TE may include a plurality of strip-shaped electrode lines L extending along a first direction D1, for example, three electrode lines L shown in fig. 2A, and the plurality of electrode lines L may be arranged at intervals along a second direction D2 and connected in parallel, wherein the first direction D1 is perpendicular to the second direction D2. In the present embodiment, the touch sensing electrode TE has a wave-shaped electrode pattern. However, the shape and arrangement of the touch sensing electrodes TE are not limited thereto, and in other embodiments, the touch sensing electrodes TE may have other suitable shapes and arrangements.

Fig. 2C is a partially enlarged schematic view of the region R of the touch sensor 100 of fig. 2B. Please refer to fig. 2B and fig. 2C. In some embodiments, the metal nanowire layer 120 is a surface-treated metal nanowire layer 120. In more detail, the metal nanowire layer 120 may include a matrix 124, first metal nanowires 122A and second metal nanowires 122B, wherein the first metal nanowires 122A are completely located in the matrix 124, the second metal nanowires 122B are adjacent to the upper surface 125 of the matrix 124 and are partially embedded in the matrix 124, and each of the second metal nanowires 122B has a first portion 122A embedded in the matrix 124 and a second portion 122B protruding from the upper surface 125 of the matrix 124. In addition, the interface of the first metal nanowire 122A and the matrix 124 has a first film structure 126A (i.e., the first film structure 126A is spaced between the first metal nanowire 122A and the matrix 124), and the interface of the first portion 122A of the second metal nanowire 122B and the matrix 124 has a second film structure 126B (i.e., the second film structure 126B is spaced between the first portion 122A of the second metal nanowire 122B and the matrix 124). If the metal nanowire layer 120 is viewed from the first portion 120a of the visible region VA, the second portion 122B of the second metal nanowire 122B is exposed from the upper surface 125 of the substrate 124; if the metal nanowire layer 120 is viewed as the second portion 120B of the peripheral region PA, the second portion 122B of the second metal nanowire 122B is embedded in the metal layer 130 located above the metal nanowire layer 120.

In some embodiments, the first film structure 126A may further cover a portion or an entire surface of each of the first metal nanowires 122A to form a first coating structure 126A, and the second film structure 126B may further cover a portion or an entire surface of the first portion 122A of each of the second metal nanowires 122B to form a second coating structure 126B. In some embodiments, the metallic nanowire layer 120 may further include a third film structure 126C that is present alone in the matrix 124 between the first metallic nanowires 122A, between the second metallic nanowires 122B, and between the first and second

metallic nanowires

122A and 122B. In other words, the third film structure 126C does not contact any of the first metal nanowires 122A or the second metal nanowires 122B.

By performing the surface treatment on the metal nanowire layer 120 by using the vacuum plasma process described above, the film structure 126 covering the second portion 122B of the second metal nanowire 122B is removed and the second portion 122B of the second metal nanowire 122B is exposed, so that the surface resistance of the metal nanowire layer 120 can be effectively reduced. On the other hand, when the metal layer 130 is lapped with the metal nanowire layer 120, since the second metal nanowires 122B of the exposed portion of the metal nanowire layer 120 can directly contact the metal layer 130, a lower lapping resistance can be formed between the metal nanowire layer 120 and the metal layer 130 to meet the requirement of the lapping resistance. Further, the size of the peripheral area PA (e.g., the width of the peripheral area PA) of the touch sensor 100 can be designed in a smaller size range due to the reduced overlap resistance between the metal nanowire layer 120 and the metal layer 130, so as to meet the specification of the narrow frame size defined in the industry.

Specifically, in the touch sensor 100 of the present disclosure, a part of the metal layer 130 overlaps and is overlapped with at least a part of the second portion 120b of the surface-treated metal nanowire layer 120 in the peripheral region PA, and the formed overlapping region a may have a thickness of 0.09mm ² To 1.20mm ² And the overlap resistance of the overlap region a is less than 50 Ω, preferably less than 40 Ω, 30 Ω or 20 Ω, and more preferably less than 10 Ω. Generally speaking, when the overlapping area of the overlapping area A is less than or equal to 1.20mm ² In this case, the design flexibility of the peripheral area PA of the touch sensor 100 can be improved, and a smaller size of the peripheral area PA can be formed, which meets the specification of the narrow frame size specified in the industry. In other words, the touch sensor 100 of the present disclosure can meet the requirement of the overlap resistance within the specification of the narrow frame size recognized in the industry. In detail, if the overlapping area of the overlapping area A is more than 1.20mm ² The size of the peripheral area PA of the touch sensor 100 needs to be correspondingly increased, so that the touch sensor 100 cannot have the narrow frame size determined in the industry; if the overlapping area of the overlapping area A is less than 0.09mm ² The overlap impedance of the overlap area a is too high (for example, greater than 50 Ω), so that the touch sensor 100 cannot meet the requirement of the overlap impedance, and the overlap area is smaller than 0.09mm ² This will also result in a structure that does not form an effective and reliable joint, and the metal layer 130 and the metal nanowire layer 120 are easily peeled off and separated. In other embodiments, the smaller size of the terminal is targetedFor an end product (e.g., a wearable device such as a watch), the overlap area a of the touch sensor 100 may further have a thickness of 0.09mm ² To 0.6mm ² And the overlap resistance of the overlap region a is less than 50 Ω, preferably less than 40 Ω, 30 Ω or 20 Ω, and more preferably less than 10 Ω, to meet the industry-defined specification for narrow bezel dimensions. It should be understood that the shape of the overlapping area a mentioned herein is illustrated by a quadrilateral, which is a design commonly used in the art, and the "overlapping area" refers to the area of a plane area formed by the length L1 and the width W1 of the overlapping area a when viewed from a top view (the perspective of fig. 2A), wherein the plane area is located on a plane formed by the first direction D1 and the second direction D2. More specifically, the "lap area" refers to a vertical projection area of the lap area a on the substrate 110, i.e. an area actually affecting the size of the peripheral area PA of the touch sensor 100.

Please refer to table one, which shows the bonding resistance of the bonding region a formed after the metal layer 130 is bonded to the metal nanowire layer 120 before and after the surface treatment through the comparative examples and the embodiments. Specifically, the metal nanowire layer 120 in each comparative example was not surface-treated, but the metal nanowire layer 120 in each example was surface-treated through the steps described above, in which a vacuum plasma process was performed on the metal nanowire layer 120 for 26 minutes using argon plasma at a power of 6kW and a flow rate of 2000 sccm. In addition, in terms of the structure after the patterning process, each of the comparative examples and each of the embodiments uses one touch sensing electrode TE and one corresponding peripheral line T as a set to measure the bonding area a. Referring to fig. 3, a schematic diagram illustrating a method for measuring a bonding impedance of a bonding area a according to some embodiments of the present disclosure is shown. The measuring equipment is adopted

B2912A type power supply measuring equipment is matched with a probe, and measurement is performed under normal temperature environment, wherein in the measuring process, each measuring section (such as a point X-point Y section, a point X-point Z section and a point W-point Y section) is pointed atSegment) to provide a constant input current (10 μ a) to measure the output voltage and to convert the resistance impedance in ohm's law.

The method for measuring the lap joint impedance of the lap joint area A comprises the following steps: the first step is as follows: one probe of the power measuring device is contacted to any position (point X) of the peripheral circuit T, and the other probe is contacted to any position (point Y) of the touch sensing electrode TE to measure and obtain the impedance _(X-Y) . The second step is as follows: one probe is maintained at the point X contacting the peripheral circuit T in the first step, and the other probe is changed to contact the peripheral circuit T at the position (point Z) at the edge of the bonding region A to measure and obtain the impedance _(X-Z) . The third step: contacting one probe with the point Y of the touch sensing electrode TE in the first step and contacting the other probe with the position (point W) of the touch sensing electrode TE at the edge of the lap joint area A to measure and obtain the impedance _(W-Y) . Thus, the impedances are obtained respectively _(X-Y) Impedance, impedance _(X-Z) And impedance _(W-Y) Then, with the formula: impedance(s) _(X-Y) -impedance _(X-Z) -impedance _(W-Y) To obtain the lap joint resistance (i.e., resistance) of the lap joint region a _(W-Z) ). Other details of the lap area a and the measurement results of the comparative examples and the examples are shown in table one.

Watch 1

Note: when the impedance measurement result is less than 1 Ω, it is recorded as 1 Ω.

From the measurement results in table one, the bonding region a formed by bonding the metal layer 130 and the metal nanowire layer 120 without surface treatment has a smaller bonding area (e.g., 0.09 mm) ² To 1.20mm ² The area of the joint) the resistance value of the joint resistance is larger than 50 omega. In contrast, the metal layer 130 overlaps the surface-treated metal nanowire layer 120 to form an overlapping region a having a small overlapping area (e.g., 0.09 mm) ² To 1.20mm ² Lap area of (2)The resistance value of the lap joint resistance is less than 50 omega (can even be almost maintained in the range of less than or equal to 1 omega). In other words, the touch sensor 100 of the present disclosure can still meet the requirement of low overlap resistance under the condition of meeting the specification of the narrow frame size recognized in the industry. It is worth mentioning that when the overlapping area of the overlapping area A is larger than 1.2mm ² When (in table one, the overlapping area is 1.6mm ² For example), although the bonding resistance can be maintained in a range of less than 50 Ω under the condition that the metal nanowire layer 120 is not surface-treated, the bonding area is more than 1.2mm ² The touch sensor 100 in the overlap area a is less able to meet the industry-defined specification for the size of the narrow bezel.

Please refer to table two, which shows the measurement results of the bonding region a formed by bonding the metal layer 130 and the metal nanowire layer 120 before and after the surface treatment in the normal temperature environment after the reliability test in the high temperature and high humidity environment, wherein the high temperature and high humidity environment is HS6590 (the temperature is 65 ℃, and the relative humidity is 90%). Specifically, the metal nanowire layer 120 in each comparative example was not surface-treated, but the metal nanowire layer 120 in each example was surface-treated through the steps described above, in which a vacuum plasma process was performed on the metal nanowire layer 120 for 26 minutes at a flow rate of 2000sccm using argon plasma. In addition, the measuring method and the measuring equipment used in the room temperature environment are the same as those in the embodiment of the table one. Additional details and measurements of the lap area a for each of the comparative examples and each of the examples are shown in table two.

Watch 2

From the measurement results of Table two, the lap area in the lap area A is 0.09mm ² To 1.20mm ² Meanwhile, the touch sensor 100 formed by the metal layer 130 and the metal nanowire layer 120 without surface treatment being connected to each other cannot be miniaturized before the high temperature and high humidity environment test is performedAt a 50 omega junction resistance. In contrast, after the touch sensor 100 formed by the metal layer 130 and the surface-treated metal nanowire layer 120 being lapped is tested for 120 hours in a high-temperature and high-humidity environment, the lapping resistance is measured in a normal-temperature environment, and the measurement result shows that the resistance value of the lapping resistance is still less than 50 Ω, which shows that the touch sensor 100 with the surface-treated metal nanowire layer 120 can meet the requirement of low lapping resistance after being tested in a high-temperature and high-humidity environment under the condition of meeting the specification of the narrow frame size identified in the industry.

Incidentally, if the touch sensor 100 has a plurality of touch sensing electrodes TE, in the touch sensor 100 formed by overlapping the metal layer 130 and the surface-treated metal nanowire layer 120 according to the present disclosure, the difference between the overlapping impedances corresponding to different touch sensing electrodes TE can be maintained within ± 2.5 Ω. Conversely, in the touch sensor 100 formed by bonding the metal layer 130 and the metal nanowire layer 120 without surface treatment, the difference between the bonding impedances corresponding to different touch sensing electrodes TE may be as high as ± 30 Ω. In view of this, the touch sensor 100 of the present disclosure not only can provide a lower landing impedance, but also has a better uniformity among the landing impedances of different touch sensing electrodes TE.

In the following description, a method for manufacturing the touch sensor 100 of the present disclosure will be further described by taking the surface-treated metal nanowire layer 120 shown in fig. 1A to 1E as an example of a case where the surface-treated metal nanowire layer is formed on the substrate 110 and the touch sensor 100 shown in fig. 2A to 2C as an example. It should be understood that the structure, connection and function of the elements described above will not be repeated, and will be described in detail.

The method for manufacturing the touch sensor 100 may include steps S10 to S40, and steps S10 to S40 may be performed sequentially. In step S10, a substrate 110 is provided. In step S20, a metal nanowire layer 120 is formed on the substrate 110 and correspondingly located in the visible area VA and the peripheral area PA. In step S30, the metal nanowire layer 120 is subjected to surface treatment. In step S40, a metal layer 130 is formed on the substrate 110 and correspondingly located in the peripheral region PA, wherein a portion of the metal layer 130 is stacked and contacted with the surface-treated metal nanowire layer 120 to form a bonding region a.

In some embodiments, after the step S10, a pretreatment step may be performed on the surface 111 of the substrate 110, such as performing a surface modification process or additionally coating an adhesive layer or a resin layer on the surface 111 of the substrate 110 to improve the adhesion between the substrate 110 and other layers (e.g., the metal nanowire layer 120 and/or the metal layer 130).

In some embodiments, step S20 may further include: the metal nanowire layer 120 is patterned. Specifically, after the dispersion 10 containing the metal nanowires 122 is formed on the surface 111 of the substrate 110 by coating and cured/dried to attach the metal nanowire layer 120 to the surface 111 of the substrate 110, the metal nanowire layer 120 may be patterned, so that the metal nanowire layers 120 located in the visible area VA and the peripheral area PA are defined with respective patterns. In detail, the metal nanowire layer 120 in the visible area VA may be patterned to form at least one touch sensing electrode TE, and the metal nanowire layer 120 in the peripheral area PA may be patterned to form a joint (also referred to as a first joint) for being subsequently connected to the metal layer 130. In some embodiments, the patterning of the metal nanowire layer 120 may be performed by an etching process. In some embodiments, the metal nanowire layer 120 in the visible area VA and the peripheral area PA can be etched simultaneously, and an etching mask (e.g., photoresist) is used to fabricate the patterned metal nanowire layer 120 in the visible area VA and the peripheral area PA at one time in the same process. In some embodiments, when the metal nanowires 122 in the metal nanowire layer 120 are silver nanowires, the etching solution may select a composition that can etch silver, such as H ₃ PO ₄ (in a ratio of about 55% to about 70%) and HNO ₃ (ratio about 5% to about 15%) to remove silver metal material. In other embodiments, the main component of the etching solution may be ferric chloride/nitric acid or phosphoric acid/hydrogen peroxide, etc. In addition, in some embodiments, the patterning process may be performed after the completion of step S30, i.e., the patterning process is performed in step S20After forming the metal nanowire layer 120 on the substrate 110, step S30 is performed to perform a surface treatment on the metal nanowire layer 120, and then a so-called patterning process is performed. In other words, the patterning process for the metal nanowire layer 120 may be performed before or after the surface treatment of the metal nanowire layer 120, and is not limited by the disclosure.

Subsequently, in step S40, the metal layer 130 is formed in the peripheral region PA, such that the metal layer 130 partially overlaps the surface-treated metal nanowire layer 120 (first overlapping portion), thereby forming an overlapping region a. In some embodiments, the metal layer 130 containing a photosensitive metal (e.g., photosensitive silver) may be entirely formed on the peripheral area PA of the substrate 110 to partially cover the first overlapping portion. Next, a patterning step may be performed on the metal layer 130 to define a pattern on the metal layer 130, and form at least one peripheral circuit T and a second bonding portion that is bonded to the first bonding portion of the metal nanowire layer 130. When the metal material in the metal layer 130 is photosensitive silver, the photosensitive silver can be directly exposed and developed to form a pattern of the metal layer 130. More specifically, by using photosensitive silver as the material of the metal layer 130, the steps of using a photoresist, exposing and developing the photoresist, and etching the metal layer 130 through the developed photoresist can be omitted. Thus, it is able to prevent the pattern of the patterned metal nanowire layer 120 from being damaged due to the etching process used to form the pattern of the metal layer 130. After the above steps, the touch sensor 100 having the lap joint area a formed by overlapping and lapping a part of the metal layer 130 and a part of the metal nanowire layer 120 in the peripheral area PA of the substrate 110 can be manufactured.

The touch sensor disclosed in the present disclosure may be assembled or integrated 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) with an optical adhesive or other adhesives, and the touch sensor may also be attached to an outer cover layer (e.g., a cover glass) with the optical adhesive. The touch sensor disclosed by the invention can also be applied to electronic equipment such as portable telephones, tablet computers, notebook computers and the like, and can also be applied to flexible products. The touch sensor disclosed herein can also be applied to polarizers (e.g., directly using the polarizer as a substrate of the touch sensor), wearable devices (e.g., smart clothes, watches, glasses, and smart shoes), and automotive devices (e.g., car recorders, dashboards, automotive rearview mirrors, and windows).

According to the above-mentioned embodiments of the present disclosure, the touch sensor of the present disclosure has a bonding region formed by bonding a portion of the metal nanowire layer and a portion of the metal layer in the peripheral region. The metal nanowire layer can be subjected to appropriate surface treatment, so that a lap joint area formed by the metal layer and the metal nanowire layer can provide a good lap joint effect within a required lap joint area range. Therefore, the touch sensor disclosed by the invention not only can have the size of the narrow frame determined in the industry, but also can have the required lap joint resistance value.

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 sensor, having a visible area and a peripheral area disposed on at least one side of the visible area, the touch sensor comprising:

a substrate;

a metal nanowire layer disposed on the substrate and having a first portion corresponding to the visible region and a second portion corresponding to the peripheral region; and

a metal layer disposed on the substrate and corresponding to the peripheral region, wherein a part of the metal layer is stacked and contacted with at least a part of the second portion of the metal nanowire layer to form a bonding region, and a bonding area of the bonding region is 0.09mm ² To 1.20mm ² And a lap resistance of the lap joint region is less than 50 omega.

2. The touch sensor of claim 1, wherein the area of the landing is a vertical projection area of the landing area on the substrate.

3. The touch sensor of claim 1, wherein the area of the overlap is between 0.09mm ² To 0.60mm ² In the meantime.

4. The touch sensor of claim 1, wherein the landing impedance is less than 40 Ω, less than 30 Ω, less than 20 Ω, or less than 10 Ω.

5. The touch sensor of claim 1, wherein the metal nanowire layer comprises:

the nanowire array comprises a matrix, a plurality of first metal nanowires and a plurality of second metal nanowires, wherein each first metal nanowire is completely positioned in the matrix, and each second metal nanowire is only partially embedded in the matrix.

6. The touch sensor of claim 5, wherein each of the second metal nanowires in the second portion of the metal nanowire layer has a first portion embedded in the matrix and a second portion protruding above an upper surface of the matrix, and the second portions of the second metal nanowires are embedded in the metal layer.

7. The touch sensor of claim 5, wherein each of the second metal nanowires has a first portion embedded in the matrix and a second portion protruding from a top surface of the matrix.

8. The touch sensor of claim 7, wherein the metal nanowire layer further comprises:

a plurality of first film structures, wherein each of the first film structures is located at an interface between each of the first metal nanowires and the substrate; and

a plurality of second film structures, wherein each of the second film structures is located at an interface between the first portion of each of the second metal nanowires and the substrate.

9. The touch sensor of claim 8, wherein each of the first film structures encapsulates each of the first metal nanowires to form a first coating structure, and each of the second film structures encapsulates the first portion of each of the second metal nanowires to form a second coating structure.

10. The touch sensor of claim 8, wherein the first film structures and the second film structures are made of a polyethylene derivative.

11. The touch sensor of claim 1, wherein the metal layer comprises photosensitive silver.

12. The touch sensor of claim 1, wherein the first portion of the metal nanowire layer forms a touch sensing electrode and a portion of the metal layer forms a peripheral circuit.

13. A method for manufacturing a touch sensor, the touch sensor having a visible area and a peripheral area disposed on at least one side of the visible area, the method comprising:

providing a substrate;

forming a metal nanowire layer on the substrate and correspondingly positioned in the visible area and the peripheral area;

performing surface treatment on the metal nanowire layer; and

forming a metal layer on the substrate and corresponding to the peripheral region, wherein part of the metal layer is stacked and contacted with the surface-treated metal nanowire layer to form a lap joint region, wherein the lap joint region is formedA lap area of the lap area is between 0.09mm ² To 1.20mm ² And a lap resistance of the lap joint region is less than 50 omega.

14. The method of claim 13, wherein the surface treating the metal nanowire layer comprises:

performing a vacuum plasma process on the metal nanowire layer, wherein the vacuum plasma process uses argon plasma with a power of 2 to 8kW and a flow rate of 1500 to 2500sccm, and the time of the vacuum plasma process is between 20 to 30 minutes.

15. The method of claim 13, wherein the metal nanowire layer comprises a substrate, a plurality of metal nanowires, and a plurality of film structures, each of the metal nanowires has a first portion embedded in the substrate and a second portion protruding from an upper surface of the substrate, each of the film structures covers each of the metal nanowires, and the surface treating the metal nanowire layer comprises:

removing each film structure covering the second part of each metal nanowire to expose the second part of each metal nanowire.

16. The method of claim 13, wherein the metal nanowire layer comprises a substrate, a plurality of metal nanowires and a plurality of film structures distributed on and within an upper surface of the substrate, and the surface treatment of the metal nanowire layer comprises:

removing the film structures distributed on the upper surface of the substrate to expose the upper surface of the substrate.

17. The method as claimed in claim 13, wherein the surface-treated metal nanowire layer comprises a substrate and a plurality of metal nanowires, wherein each of the metal nanowires has a first portion embedded in the substrate and a second portion protruding from an upper surface of the substrate, and the metal layer is formed in the peripheral region such that the second portion of each of the metal nanowires in the peripheral region is embedded in the metal layer.

18. The method of claim 13, wherein the step of forming the metal nanowire layer on the substrate comprises:

and patterning the metal nanowire layer to form a touch sensing electrode.

19. The method of claim 13, wherein the step of forming the metal layer on the substrate comprises:

the metal layer is patterned to form a peripheral circuit.