JP2022145455A - Touch sensor and manufacturing method thereof - Google Patents

Abstract

To provide a touch sensor that can satisfy the requirements of contact impedance as well as satisfying the requirements of slim bezel design which is generally recognized in the industry, and a manufacturing method of the touch sensor.SOLUTION: A touch sensor 100 having a visible area and a peripheral area located on at least one side of the visible area includes a substrate 110, a metal nanowire layer 120, and a metal layer 130. The metal nanowire layer is arranged on the substrate and includes a first part 120a corresponding to the visible area and a second part 120b corresponding to the peripheral area. The metal layer is arranged on the substrate to correspond to the peripheral area PA. A part of the metal layer comes in to contact with at least a part of the second part of the metal nanowire layer to form an overlapping area A. The contact area of the overlapping area is 0.09 mm2 to 1.20 mm2. A contact impedance of the overlapping area is less than 50 Ω.SELECTED DRAWING: Figure 2A

Description

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

In recent years, touch sensors have been widely used in portable electronic devices such as mobile phones, laptop computers, satellite navigation systems, and digital AV players as information communication channels between users and electronic devices.

As the demand for narrow-bezel electronic products gradually increases, the industry is keen to reduce the size of the bezels of electronic products to meet the needs of users. Touch sensors require a small peripheral area size. Generally, a touch sensor includes touch electrodes and peripheral circuitry, which typically overlap each other in a peripheral region to form conductive paths or loops. Factors affecting the size of the peripheral area of the touch sensor generally include the overlap tolerance between the touch electrodes and the peripheral circuits, the contact area between the touch electrodes and the peripheral circuits, and the line width and line spacing of the peripheral circuits. If the peripheral region is reduced by reducing the contact area between the touch electrode and the peripheral circuit, the contact impedance between the touch electrode and the peripheral circuit increases due to the smaller contact area, which may adversely affect the signal transmission of the touch sensor. many. Given the above, it is now worth considering how to provide a touch sensor that not only meets the narrow bezel design requirements generally accepted in the industry, but also meets the contact impedance requirements.

According to some embodiments of the present disclosure, a touch sensor having a visible area and a peripheral area on at least one side of the visible area includes a substrate, a metal nanowire layer, and a metal layer. A metal nanowire layer is disposed on the substrate and has a first portion corresponding to the visible region and a second portion corresponding to the peripheral region. A metal layer is disposed on the substrate corresponding to the peripheral region, and a portion of the metal layer overlaps and contacts at least a portion of the second portion of the metal nanowire layer to form an overlap region, wherein the overlap region is formed. The contact area of the region is between 0.09 mm ² and 1.20 mm ² and the contact impedance of the overlapping region is less than 50Ω.

In some embodiments of the present disclosure, the contact area is the vertical projected area of the overlap region on the substrate.

In some embodiments of the disclosure, the contact area is between 0.09 mm ² and 0.60 mm ² .

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

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, each of the first metal nanowires within the matrix. Fully embedded, each of the second metal nanowires is partially embedded within the matrix.

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

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

In some embodiments of the present disclosure, the metal nanowire layer further comprises a plurality of first membrane structures and a plurality of second membrane structures, each of the first membrane structures comprising a matrix and the first metal nanowires. and each of the second membrane structures is disposed at the interface between the matrix and the first portion of each of the second metal nanowires.

In some embodiments of the present disclosure, each of the first membrane structures covers each of the first metal nanowires to form a first covering structure, and each of the second membrane structures covers a second A second coating structure is formed overlying the first portion of each of the metal nanowires.

In some embodiments of the present disclosure, the material of each of the first membrane structure and the second membrane structure comprises a polyethylene derivative.

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

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

According to some other embodiments of the present disclosure, a method of manufacturing a touch sensor having a visible area and a peripheral area on at least one side of the visible area comprises the steps of providing a substrate; forming a metal nanowire layer corresponding to the peripheral region; performing surface treatment of the metal nanowire layer; forming a metal layer corresponding to the peripheral region on a substrate; is in contact with the surface-treated metal nanowire layer to form an overlap region, the contact area of the overlap region is 0.09 mm ² to 1.20 mm ² , and the contact impedance of the overlap region is 50 Ω. is less than

In some embodiments of the present disclosure, performing a surface treatment on the metal nanowire layer comprises subjecting the metal nanowire layer to a vacuum plasma treatment, the vacuum plasma treatment having a power of 2 kW to 8 kW and a flow rate of An argon plasma of 1500 sccm to 2500 sccm is used, and the vacuum plasma treatment time is 20 to 30 minutes.

In some embodiments of the present disclosure, the metal nanowire layer includes a matrix, a plurality of metal nanowires, and a plurality of membrane structures, each of the metal nanowires having a first portion embedded within the matrix; a second portion protruding from the top surface of the matrix, each of the film structures covering each of the metal nanowires; removing each of the membrane structures overlying the second portion of each of the metal nanowires such that portions are exposed.

In some embodiments of the present disclosure, the metal nanowire layer includes a matrix, a plurality of metal nanowires, and a plurality of film structures, the film structures distributed on and within the matrix, and the surface to the metal nanowire layer. Performing the process includes removing the membrane structure distributed over the top surface of the matrix such that the top surface of the matrix is exposed.

In some embodiments of the present disclosure, the surface-treated metal nanowire layer includes a matrix and a plurality of metal nanowires, each of the metal nanowires having a first portion embedded within the matrix; and a second portion protruding from the top surface of the matrix, the metal layer being formed corresponding to the peripheral region such that the second portion of each of the metal nanowires in the peripheral region is embedded within the metal layer. be.

In some embodiments of the present disclosure, forming a metal nanowire layer on the substrate includes performing a patterning process on the metal nanowire layer to form touch sensing electrodes.

In some embodiments of the present disclosure, forming a metal layer on a substrate includes performing a patterning process on the metal layer to form peripheral circuitry.

According to the foregoing embodiments of the present disclosure, the touch sensor of the present disclosure has an overlap region formed by overlapping a portion of the metal nanowire layer and a portion of the metal layer in the peripheral region. The metal nanowire layer of the present disclosure may be subjected to appropriate surface treatment so that the metal layer and the overlapping region formed by the metal nanowire layer have the required contact area and provide good contact effect. . Thus, the touch sensor of the present disclosure not only meets the industry commonly recognized narrow-bezel design requirements, but can also meet contact impedance requirements.

The present disclosure can be more fully understood by reading the following detailed description of embodiments with reference to the accompanying drawings.
4A-4D are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer in different steps, according to some embodiments of the present disclosure; 4A-4D are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer in different steps, according to some embodiments of the present disclosure; 4A-4D are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer in different steps, according to some embodiments of the present disclosure; 4A-4D are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer in different steps, according to some embodiments of the present disclosure; 4A-4D are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer in different steps, according to some embodiments of the present disclosure; FIG. 3 is a schematic plan view of a touch sensor according to some embodiments of the present disclosure; 2B is a schematic cross-sectional view showing the touch sensor of FIG. 2A along line 2B-2B, according to some embodiments of the present disclosure; FIG. 2C is a schematic enlarged partial view showing region R of the touch sensor in FIG. 2B, according to some embodiments of the present disclosure; FIG. FIG. 4 is a schematic diagram showing a method of measuring contact impedance of an overlap region;

Reference will now be made in detail to the present embodiments of the disclosure as illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

Although the terms “first,” “second,” and “third” may be used herein to describe various elements, components, regions, layers, and/or portions, these It should be understood that elements, components, regions, layers, 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, reference to a "first element," "component," "region," "layer," or "portion" discussed below may be used to refer to a second element, component, region, or region without departing from the teachings of the present disclosure. , layers, or portions.

Furthermore, relative terms such as "lower" or "bottom" and "upper" or "top" are used herein as shown in the figure: It can be used to describe the relationship between one element and another. It should be understood that relative terms are intended to include different orientations of the device other than that shown in the figures. For example, when the device in one figure is turned over, elements described as being on the "bottom" side of other elements will face the "top" side of the other elements. Thus, the exemplary term "below" may include an orientation of "below" and "above," depending on the particular orientation of the drawing. Similarly, when the device in one figure is flipped over, elements described as "below" other elements face "above" the other elements. Thus, the exemplary term "below" can include "up" and "down" orientations.

The present disclosure provides a touch sensor that not only meets the narrow bezel size requirements commonly recognized in the industry, but also meets the contact impedance requirements. The present disclosure includes methods of performing surface treatments on metal nanowire layers (ie, layers containing metal nanowires) and touch sensors fabricated with surface treated metal nanowire layers. It should be understood that in this disclosure, for clarity and convenience of explanation, methods of performing surface treatments on metal nanowire layers will be discussed preferentially.

1A-1E are schematic cross-sectional views illustrating methods of surface treatment to a metal nanowire layer 120 in different steps, according to some embodiments of the present disclosure. See FIG. 1A. First, a dispersion liquid 10 is prepared. In some embodiments, the dispersion 10 can be, for example, a mixture of solvent, filler, and metal nanowires 122, wherein the filler and solvent are uniformly mixed, and the metal nanowires 122 are the mixed filler and solvent. dispersed within. In some embodiments, the solvent may be water, alcohols, ketones, ethers, hydrocarbons, aromatic solvents (benzene, toluene, xylene, etc.), or combinations thereof. In some embodiments, fillers can include insulating materials. For example, the insulating material may be a non-conductive resin or other organic material such as polyacrylate, epoxy resin, polyurethane, polysilane, polysiloxane, polyethylene, polypropylene, polycarbonate, polyvinyl butyral, poly(silicon-acryl), poly(styrene sulfone). acid), acrylonitrile-butadiene-styrene copolymer, poly(3,4-ethylenedioxythiophene), ceramic materials, or combinations thereof. In some embodiments, the metal nanowires 122 can be, for example, but not limited to, silver nanowires, gold nanowires, copper nanowires, nickel nanowires, or combinations thereof.

As used herein, the term “metal nanowires” is a collective noun and refers to a collection of metal wires that includes multiple metal elements, metal alloys, or metal compounds (including metal oxides) and contains therein It should be appreciated that the number of metal nanowires included does not affect the scope of the present disclosure. In some embodiments, the cross-sectional size (eg, cross-sectional diameter) of a single metal nanowire can be less than 500 nm, preferably less than 100 nm, more preferably less than 50 nm. In some embodiments, the metal nanowires have a large aspect ratio (length:cross-sectional diameter). Specifically, the aspect ratio of the metal nanowires may be from 10 to 100,000. More particularly, the aspect ratio of the metal nanowires may be greater than 10, preferably greater than 50, more preferably greater than 100. Additionally, other terms such as silk, fiber, or tube also have the cross-sectional dimensions and aspect ratios described above and are within the scope of this disclosure.

In some embodiments, dispersion 10 can include a polymer binder to improve compatibility between metal nanowires 122, solvents, and fillers, and stability of metal nanowires 122 in solvents and fillers. In some embodiments, polymeric binders can include polyethylene derivatives such as polyvinylpyrrolidone (PVP). In some embodiments, dispersion 10 may further include additives and/or surfactants. Specifically, the additive and/or surfactant may be, for example, carboxymethylcellulose, hydroxyethylcellulose, hypromellose, fluorosurfactants, sulfosuccinate sulfonates, sulfates, phosphates, disulfonates, or combinations thereof. good.

See FIG. 1B. Next, a substrate 110 is prepared and the dispersion 10 containing metal nanowires 122 is coated on the surface 111 of the substrate 110 . When viewed on a microscopic scale, the metal nanowires 122 are randomly distributed in the dispersion liquid 10 without directionality, and some of the metal nanowires 122 are distributed near the liquid surface 11 of the dispersion liquid 10. , the liquid surface 11 of the dispersion 10 is uneven and wavy. In some embodiments, metal nanowires 122 can contact each other to provide a continuous current path to form a conductive network. That is, the metal nanowires 122 make contact at their intersections to form a path for electron movement. Taking silver nanowires as an example, one silver nanowire and another silver nanowire can form direct contacts at their intersections to form a low resistance path for electron transfer. Moreover, the dispersion 10 coated on the surface 111 of the substrate 110 can completely cover each of the metal nanowires 122 in the dispersion 10, and the solvents and fillers in the dispersion 10 are Uniformly mixed without forming agglomerates or sediments.

See FIG. 1C. Next, a curing/drying process is performed to fully cure the dispersion 10 coated on the surface 111 of the substrate 110 by light, heat, or other methods, thereby forming the metal nanowire layer 120. . Specifically, after the curing/drying process, the solvent in the dispersion liquid 10 is volatilized and the filler is cured to form the matrix 124 , and the metal nanowires 122 can be randomly distributed within the matrix 124 . In some embodiments, the polymer binder in dispersion 10 is also cured to form multiple film structures 126 in metal nanowire layer 120 . More specifically, some of the polymer binder may be inside the dispersion 10 and some of the polymer binder may be in the upper layer (part) of the dispersion 10 prior to the curing/drying step. good too. Thus, a portion of the membrane structure 126 can be formed inside the matrix 124 and a portion of the membrane structure 126 can be formed on the upper surface 125 of the matrix 124 after the curing/drying process. In some embodiments, the membrane structures 126 within the matrix 124 can be randomly distributed within the matrix 124, for example, and the membrane structures 126 on the top surface 125 of the matrix 124 can be, for example, on the top surface 125 of the matrix 124. can be formed entirely over the film layer 126 .

In some embodiments, the polymer binder inside the dispersion 10 can be further cured along the surface of the metal nanowires 122 during the curing/drying process. Thus, some of the membrane structures 126 can be formed at the interfaces between the metal nanowires 122 and the matrix 124, and some of the membrane structures 126 are isolated between adjacent metal nanowires 122 within the matrix 124. can exist. In some embodiments, membrane structure 126 can cover each of metal nanowires 122 to form covering structure 126 . In some embodiments, the covering structure 126 may cover a portion of the surface of each of the metal nanowires 122, for example. In some other embodiments, the covering structure 126 may cover the entire surface of each of the metal nanowires 122, for example. In some embodiments, the coverage of the covering structure 126 is greater than about 80%, about 90% to about 95%, about 90% to about 99%, or about 90% to 100% of the total surface area of the metal nanowires 122. may be It should be understood that when the coverage of the covering structure 126 is said to be 100%, it means that the entire surface of the metal nanowires 122 is not exposed. Since the metal nanowires 122 of the present disclosure can contact each other to form a conductive network, the coating structure 126 is substantially over the entire surface of the metal nanowires 122 contacting each other to cover the entire conductive network. It is worth noting that they are formed continuously and do not affect the contact between metal nanowires 122 . In some embodiments, covering structure 126 may, for example, cover the surface of each of metal nanowires 122 in a conformal manner.

The metal nanowires 122 near the top surface 121 of the metal nanowire layer 120 each have a first portion 122a embedded in the matrix 124 and a second portion 122b protruding from the top surface 125 of the matrix 124. , and the surface of each of the metal nanowires 122 is covered with a covering structure 126 . In other words, the covering structure 126 covering the first portions 122a of the metal nanowires 122 is disposed at the interface between the matrix 124 and the metal nanowires 122 (i.e., the matrix 124 and the first portions 122a of the metal nanowires 122 are The covering structure 126 covering the second portions 122b of the metal nanowires 122 (spaced from each other by the covering structure 126) is exposed to the outside of the matrix 124. FIG. Viewing the metal nanowire layer 120 as a whole, the metal nanowire layer 120 can include a matrix 124 , metal nanowires 122 and a membrane structure 126 . Membrane structure 126 may reside solely within matrix 124 , may form film layer 126 over top surface 125 of matrix 124 , or may form covering structure 126 over each of metal nanowires 122 . and the material of the membrane structure 126 may include polyethylene derivatives such as polyvinylpyrrolidone.

See FIG. 1D. Subsequently, the cured/dried metal nanowire layer 120 may be surface treated. The surface-treated metal nanowire layer 120 can have a lower surface resistance so as to electrically overlap other conductive layers (eg, metal layers whose specific structures are detailed below). Regarding the surface treatment method, for example, after the metal nanowire layer 120 is formed, the metal nanowire layer 120 is subjected to vacuum plasma treatment to form a film structure (film layer) 126 on the upper surface 125 of the matrix 124 and the metal The membrane structure (covering structure) 126 covering the second portions 122b of the nanowires 122 can be removed to expose the top surface 125 of the matrix 124 and the second portions 122b of the metal nanowires 122. FIG. In some embodiments, the surface treatment is a vacuum plasma treatment with argon plasma (AP) at a power of 2 kW to 8 kW and a flow rate of 1500 sccm to 2500 sccm (preferably a flow rate of 1900 sccm to 2100 sccm) for 20 minutes to the metal nanowire layer 120. It is done by running for 30 minutes. The surface-treated metal nanowire layer 120 has a film structure (film layer) 126 on the upper surface 125 of the matrix 124 and a film structure (covering structure) covering the second portions 122b of the metal nanowires 122, as shown in FIG. 1E. ) 126 is removed, leaving a membrane structure 126 within the matrix 124 (including the membrane structure (covering structure) 126 that covers the metal nanowires 122 and the membrane structure 126 that exists alone within the matrix 124). After the surface treatment, the second portions 122b of the metal nanowires 122 near the top surface 125 of the matrix 124 can be completely exposed without being covered by the film structure 126, so that the surface-treated metal nanowire layer 120 is It has a lower surface resistance, which can be reduced by about 5% to about 10% compared to the surface resistance of the metal nanowire layer 120 without surface treatment. Thus, the metal nanowire layer 120 can have a lower overlap impedance when overlapping another subsequently formed conductive layer.

The above methods of the present disclosure can be applied to the manufacture of touch sensors. Specifically, refer to FIGS. 2A and 2B. FIG. 2A is a schematic plan view illustrating touch sensor 100 according to some embodiments of the present disclosure, and FIG. 2B is touch sensor 100 along line 2B-2B of FIG. 2A according to some embodiments of the present disclosure. It is a schematic cross-sectional view showing the. In some embodiments, touch sensor 100 may include substrate 110 , metal nanowire layer 120 and metal layer 130 . Substrate 110 is configured to support metal nanowire layer 120 and metal layer 130 and may be, for example, a rigid transparent substrate or a flexible transparent substrate. In some embodiments, the substrate 110 material is glass, acrylic, polyvinyl chloride, cycloolefin polymer, cycloolefin copolymer, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, colorless polyimide, or combinations thereof. Including but not limited to transparent materials. In some embodiments, the touch sensor 100 has a visible area VA and a peripheral area PA, and the peripheral area PA is arranged laterally of the visible area VA. For example, the peripheral area PA may be a frame-shaped area arranged around the visible area VA (that is, including the right side, the left side, the upper side, and the lower side). As another example, the peripheral area PA may be an L-shaped area arranged on the left side and below the visible area VA.

In some embodiments, the metal nanowire layer 120 and the metal layer 130 are continuously disposed on the substrate 110 and in the peripheral area PA, and a portion of the metal layer 130 overlaps a portion of the metal nanowire layer 120. contact to form an overlap region A; More specifically, the metal nanowire layer 120 has a first portion 120a within the visible area VA and a second portion 120b within the peripheral area PA. The first portion 120a of the metal nanowire layer 120 constitutes the touch sensing electrode TE, and at least part of the second portion 120b of the metal nanowire layer 120 is located in the peripheral area PA and constitutes the peripheral circuit T. 130 in overlapping contact to form an overlap region A. An electronic transmission path for signal transmission such as touch control can be formed across the visible area VA and the peripheral area PA in the touch sensor 100 via the overlapping portion between the metal layer 130 and the metal nanowire layer 120. can. It should be noted that the metal nanowire layer 120 and the metal layer 130 described in the present disclosure are merely used for convenience in describing the laminated structure. Indeed, the metal nanowire layer 120 may be patterned to include at least one touch sensing electrode TE, and the metal layer 130 is patterned to include at least one peripheral circuit T corresponding to the touch sensing electrode TE. The overlapping area A of the present disclosure refers to the area formed by one peripheral circuit T and one touch sensing electrode TE in contact with each other.

In some embodiments, one touch sensing electrode TE may include multiple strip-shaped electrode lines L extending along the first direction D1, such as the three electrode lines L shown in FIG. 2A, The electrode lines L may be spaced apart along the second direction D2 and connected in parallel such that the first direction D1 is orthogonal to the second direction D2. In this embodiment, the touch sensing electrodes TE have a wave-shaped electrode pattern. However, the shape and arrangement of the touch sensing electrodes TE are not limited to this. In some other embodiments, the touch sensing electrodes TE may have other suitable shapes and arrangements.

FIG. 2C is a schematic enlarged partial view showing region R of touch sensor 100 in FIG. 2B, according to some embodiments of the present disclosure. See FIGS. 2B and 2C. In some embodiments, the metal nanowire layer 120 is a surface-treated metal nanowire layer 120 . More specifically, the metal nanowire layer 120 may include a matrix 124, a plurality of first metal nanowires 122A, and a plurality of second metal nanowires 122B, wherein the first metal nanowires 122A are within the matrix 124. fully embedded, the second metal nanowires 122B are near the top surface 125 of the matrix 124 and partially embedded within the matrix 124, each of the second metal nanowires 122B embedded within the matrix 124 is the first and a second portion 122b protruding from the top surface 125 of the matrix 124 . Further, the interface between the matrix 124 and each of the first metal nanowires 122A has a first membrane structure 126A (i.e., the matrix 124 and each of the first metal nanowires 122A is a first membrane separated from each other by structures 126A), the interface between the matrix 124 and the first portion 122a of each of the second metal nanowires 122B has a second membrane structure 126B (i.e., the matrix 124 and the second are separated from each other by a second membrane structure 126B). When viewed from the first portion 120a of the metal nanowire layer 120 in the visible region VA, the second portion 122b of the second metal nanowires 122B are exposed from the top surface 125 of the matrix 124. FIG. When viewed from the second portion 120b of the metal nanowire layer 120 in the peripheral area PA, the second portion 122b of the second metal nanowire layer 122B is embedded in the metal layer 130 above the metal nanowire layer 120. FIG.

In some embodiments, the first membrane structure 126A may further cover part or all of each of the first metal nanowires 122A to form a first covering structure 126A and a second membrane structure. 126B may also cover part or all of the first portion 122a of each of the second metal nanowires 122B to form a second covering structure 126B. In some embodiments, the metal nanowire layer 120 is within the matrix 124 between the first metal nanowires 122A, between the second metal nanowires 122B, and between the first metal nanowires 122A and the second metal nanowires 122B. It may further include a plurality of third membrane structures 126C that exist alone. In other words, the third membrane structure 126C does not contact either the first metal nanowires 122A or the second metal nanowires 122B.

The vacuum plasma treatment described above is performed to surface-treat the metal nanowire layer 120, remove the film structure 126 covering the second portions 122b of the second metal nanowires 122B, and remove the second metal nanowires 122B. By exposing the second portion 122b, the surface resistance of the metal nanowire layer 120 can be effectively reduced. Furthermore, when the metal layer 130 and the metal nanowire layer 120 overlap, the exposed portion of the second metal nanowires 122B in the metal nanowire layer 120 can directly contact the metal layer 130, so that the metal nanowire layer 120 and the metal layer 130 A lower contact impedance is formed between and satisfies the contact impedance requirements. In addition, the size of the peripheral area PA of the touch sensor 100 (for example, the width of the peripheral area PA) can be designed to fall within a smaller size range due to the reduction in contact impedance, which is generally recognized in the industry. It can meet the narrow bezel size specifications.

Specifically, in the touch sensor 100 of the present disclosure, a portion of the metal layer 130 in the peripheral area PA overlaps at least a portion of the second portion 120b of the metal nanowire layer 120 subjected to surface treatment, The contact area of the formed overlap region A is 0.09 mm ² to 1.20 mm ² and the contact impedance of the overlap region A is less than 50Ω, preferably less than 40Ω, less than 30Ω or less than 20Ω, more preferably less than 10Ω. . In general, when the contact area of the overlapping area A is 1.20 mm ² or less, the design of the peripheral area PA of the touch sensor 100 can be flexible, and the size of the peripheral area PA can be relatively small. , the touch sensor 100 can meet industry-recognized narrow bezel size specifications.
In other words, the touch sensor 100 of the present disclosure can simultaneously meet industry-recognized narrow bezel size specifications and contact impedance requirements. Specifically, when the contact area of the overlapping area A exceeds 1.20 mm ² , the size of the peripheral area PA of the touch sensor 100 needs to be increased, and the touch sensor 100 is generally recognized in the industry. Inability to meet narrow bezel size specifications. If the contact area of the overlapping region A is less than 0.09 mm ² , the contact impedance of the overlapping region A becomes too high (eg, 50Ω or more), and the touch sensor 100 cannot meet the contact impedance requirements. Furthermore, if the contact area is less than 0.09 mm ² , it will not be possible to form an effective and reliable overlap in the structure, and the metal layer 130 and metal nanowire layer 120 will be easily peeled off and separated. . In some other embodiments, for smaller sized products (eg, wearable devices such as watches), the overlapping area A of the touch sensor 100 further provides a contact area of 0.09 mm ² to 0.6 mm ² . and the contact impedance of the overlap region A is less than 50Ω, preferably less than 40Ω, less than 30Ω or less than 20Ω, more preferably less than less than 10Ω. Note that the shape of the overlap region A in the present disclosure is an example of a quadrangle generally designed in the technical field, and the “contact area” refers to the first direction D1 and the second direction D2. is understood to mean the area of the planar region of the overlapping region A formed by the length L1 and the width W1 when viewed in plan view (viewing angle in FIG. 2A) located on the plane formed by sea bream. More specifically, the “touch area” is the vertical projected area of the overlapping area A on the substrate 110 and is the area that actually affects the size of the peripheral area PA of the touch sensor 100 .

Table 1 specifically shows the contact impedance of the overlap region A in each comparative example and example when the overlap region A is formed by overlapping the metal nanowire layer 120 and the metal layer 130 before and after the surface treatment. It is a thing. Specifically, the metal nanowire layer 120 in each comparative example was not surface-treated, and the metal nanowire layer 120 in each example was surface-treated through the above-described steps. The metal nanowire layer 120 in is vacuum plasma treated with an argon plasma with a power of 6 kW and a flow rate of 2000 sccm for 26 minutes. Also, the measurement of the overlapping area A in each of the comparative examples and the working examples is performed using a structure in which one corresponding peripheral circuit T is overlapped with one touch sensing electrode TE. A method of measuring the contact impedance of the overlapping region A in each of the comparative examples and examples will be described with reference to FIG. 3. FIG. The measuring device is a Keysight (trademark) B2912A type power measuring device with a probe, and the measurement is performed in a normal temperature environment. During measurement, a constant input current (10 μA) is applied to each measurement section (eg, XY section, XZ section, and WY section), the output voltage is measured, and the resistive impedance is determined by Ohm's law. is converted to

Specifically, the method for measuring the contact impedance of the overlap region A includes the following steps. Step 1: Contact a first probe of the power measuring device to an arbitrary position (point X) of the peripheral circuit T, and a second probe to contact an arbitrary position (point Y) of the touch sensing electrode TE, so that the impedance _(XY) is obtained. Step 2: While keeping the first probe in contact with the point X of the peripheral circuit T, move the second probe so as to contact the peripheral circuit T at the end of the overlapping area A (point Z), and the impedance _{( XZ)} . Step 3: Contact the first probe of the power measuring device to the point Y of the touch sensing electrode TE, and the second probe to contact the touch sensing electrode TE at the end of the overlapping area A (point W) to determine the impedance _{( WY)} . After obtaining impedance _(XY) , impedance _(XZ) , and impedance _(WY ), the contact impedance of overlapping area A (that is, impedance _(WZ) ) is obtained by [impedance _{(XY )} −Impedance _(XZ) −Impedance _(WY) ]=Impedance _(WZ) . Table 1 shows other detailed descriptions and measurement results of the overlapping region A of each comparative example and example.

注：インピーダンスの測定結果が１Ω未満の場合、インピーダンスは１Ωとして記録される。

Note: If the measured impedance is less than 1Ω, the impedance is recorded as 1Ω.

From the measurement results in Table 1, when the contact area of the overlapping region A formed by overlapping the metal nanowire layer 120 and the metal layer 130 that are not surface-treated is small (for example, the contact area is 0.09 mm ² to 1 .20 mm ² ), and the contact impedance is found to be greater than 50Ω. On the other hand, when the contact area of the overlapping region A formed by overlapping the metal nanowire layer 120 and the metal layer 130 subjected to surface treatment is small (for example, the contact area is 0.09 mm ² to 1.20 mm ² ), the contact The impedance is less than 50Ω (or the contact impedance may be 1Ω or less). In other words, the touch sensor 100 of the present disclosure can meet industry commonly recognized narrow bezel size specifications while still meeting low contact impedance requirements. When the contact area of the overlapping region A is more than 1.2 mm ² (for example, the contact area is 1.6 mm ² in Table 1), the contact impedance should be less than 50 Ω even if the metal nanowire layer 120 is not surface-treated. However, a touch sensor 100 having an overlapping area A with a contact area greater than 1.2 mm ² cannot meet the narrow bezel size specification commonly recognized in the industry.

Table 2 specifically shows the measurement results of the overlapping region A formed by overlapping the metal nanowire layer 120 and the metal layer 130 before and after the surface treatment under normal temperature environment in each comparative example and example. The overlap area A is placed in a high temperature and high humidity environment, the high temperature and high humidity environment being the HS6590 environment (ie temperature 65° C., relative humidity 90%). Specifically, the metal nanowire layer 120 in each comparative example was not surface-treated, and the metal nanowire layer 120 in each example was surface-treated through the above-described steps. The metal nanowire layer 120 in has been vacuum plasma treated with an argon plasma with a flow rate of 2000 seem for 26 minutes. In addition, the measuring method and measuring apparatus used under the room temperature environment are the same as the measuring method and measuring apparatus in Table 1 above. Table 2 shows other detailed descriptions and measurement results of the overlapping region A of each comparative example and example.

From the measurement results in Table 2, when the contact area of the overlap region A is 0.09 mm ² to 1.20 mm ² , the touch formed by overlapping the metal nanowire layer 120 and the metal layer 130 without surface treatment. It can be seen that the sensor 100 cannot have a contact impedance of less than 50Ω even before being placed in a hot and humid environment. On the other hand, the touch sensor 100 formed by superimposing the metal nanowire layer 120 and the metal layer 130 subjected to the surface treatment has a resistance of 50Ω in a room temperature environment even after being placed in a high temperature and high humidity environment for 120 hours. can have a contact impedance of less than The measurement results show that the touch sensor 100 with the surface-treated metal nanowire layer 120 is exposed to a high temperature and high humidity environment while meeting industry-recognized narrow bezel size specifications. , indicating that the requirement for low contact impedance can be met.

Note that when the touch sensor 100 has a plurality of touch sensing electrodes TE, the touch sensor 100 of the present disclosure, which is formed by superimposing the metal nanowire layer 120 and the metal layer 130 subjected to surface treatment, has different touch sensing electrodes. The contact impedance difference corresponding to the TE can be maintained within ±2.5Ω. On the other hand, in the touch sensor 100 formed by overlapping the metal nanowire layer 120 and the metal layer 130 without surface treatment, the difference in contact impedance corresponding to different touch sensing electrodes TE may reach ±30Ω. . Thus, the touch sensor 100 of the present disclosure not only provides lower contact impedance, but also better uniformity between contact impedances of different touch sensing electrodes TE.

In the following description, the touch sensor 100 shown in FIGS. A method of manufacturing the sensor 100 will be further described. It should be understood that the configuration, connections and advantages of the components described above will not be repeated below.

The method for manufacturing the touch sensor 100 may include steps S10 to S40, and steps S10 to S40 may be performed continuously. In step S10, the substrate 110 is prepared. In step S20, a metal nanowire layer 120 is formed on the substrate 110 corresponding to the visible area VA and the peripheral area PA. In step S30, the metal nanowire layer 120 is surface-treated. In step S40, a metal layer 130 is formed on the substrate 110 corresponding to the peripheral area PA, and a portion of the metal layer 130 overlaps and contacts the surface-treated metal nanowire layer 120 to form an overlapping area A. be done.

In some embodiments, post-processing may be performed on the substrate 110 after step S10, such as performing a surface modification process or applying an adhesive layer or a resin layer on the surface 111 of the substrate 110. to enhance adhesion between substrate 110 and other layers (eg, metal nanowire layer 120 and/or metal layer 130).

In some embodiments, step S20 may further include performing a patterning process on the metal nanowire layer 120. FIG. Specifically, the dispersion 10 containing the metal nanowires 122 is coated on the surface 111 of the substrate 110 and cured/dried to adhere the metal nanowire layer 120 to the surface 111 of the substrate 110 . A patterning process may be performed on the metal nanowire layer 120 in the visible area VA and the peripheral area PA, respectively, to define the pattern. Specifically, the metal nanowire layer 120 in the visible area VA can be patterned to form at least one touch sensing electrode TE, and the metal nanowire layer 120 in the peripheral area PA is followed by the metal layer It can be patterned to form an overlap (also referred to as a first overlap) that overlaps 130 . In some embodiments, the metal nanowire layer 120 can be patterned 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 with the aid of an etch mask (e.g., photoresist) such that the patterned metal nanowire layer 120 is visible. The area VA and the peripheral area PA are formed by the same process. More specifically, when the metal nanowires 122 in the metal nanowire layer 120 are silver nanowires, the main component of the etchant is H ₃ PO ₄ (the volume of H ₃ PO ₄ in the etchant) to remove the silver material. about 55% to about 70%) and HNO ₃ (about 5% to about 15% by volume of HNO ₃ in the etchant). In some other embodiments, the main components of the etchant may be ferric chloride/nitric acid or phosphoric acid/hydrogen peroxide. Additionally, in some embodiments, a patterning process may be performed after step S30. That is, after step S20 is performed to form the metal nanowire layer 120 on the substrate 110, step S30 is performed to perform the surface treatment on the metal nanowire layer 120, and then the patterning process is performed. In other words, the patterning treatment of the metal nanowire layer 120 can be performed before or after the surface treatment of the metal nanowire layer 120, and the present disclosure is not limited thereto.

Subsequently, in step S40, the metal layer 130 is formed in the peripheral area PA such that the metal layer 130 partially overlaps the surface-treated metal nanowire layer 120 (that is, the first overlapping portion). Form area A. In some embodiments, a metal layer 130 comprising a photosensitive metal (eg, photosensitive silver) may be formed over the entire surface of the peripheral area PA of the substrate 110 to partially cover the first overlapping portion. . The metal layer 130 may then be patterned to define a pattern of the metal layer 130 to form at least one peripheral circuit T and a second overlap portion overlapping the first overlap portion of the metal nanowire layer 120. . If the material of the metal layer 130 is photosensitive silver, the photosensitive silver can be directly exposed and developed to form the pattern of the metal layer 130 . More specifically, by using photosensitive silver as the material of the metal layer 130, the steps of applying a photoresist, exposing and developing the photoresist, and etching the metal layer 130 through the developed photoresist are performed. can be omitted. Therefore, damage to the pattern of the metal nanowire layer 120 due to the etching process performed to form the pattern of the metal layer 130 can be prevented. Through the above steps, the touch sensor 100 having the overlapping area A formed by overlapping and contacting in the peripheral area PA between a portion of the metal layer 130 and a portion of the metal nanowire layer 120 can be manufactured.

The touch sensor of the present disclosure can be assembled with other electronic devices such as displays with touch capabilities. For example, the substrate can be adhered to a display device (eg, a liquid crystal display device or an organic light emitting diode display device), and an optical adhesive or other adhesive can be used to adhere therebetween. The touch sensor may be adhered to the outer cover layer (eg protective glass) via an optical adhesive. The touch sensor of the present disclosure can also be applied to electronic devices such as mobile phones, tablets, and laptops, and can also be applied to flexible products. The touch sensors of the present disclosure can be applied to polarizers (e.g., polarizers can be used directly as substrates for touch sensors), wearable devices (e.g., watches, eyeglasses, smartwear, smart shoes), and automotive devices (e.g., dashboards, drive recorders, rearview mirrors, windows, etc.).

According to the foregoing embodiments of the present disclosure, the touch sensor of the present disclosure has an overlap region formed by a portion of the metal nanowire layer and a portion of the metal layer overlapping each other in the peripheral region. The metal nanowire layer of the present disclosure may be subjected to appropriate surface treatment so that the metal layer and the overlapping region formed by the metal nanowire layer have the required contact area and provide good contact effect. . Thus, the touch sensor of the present disclosure not only meets the industry commonly recognized narrow-bezel design requirements, but can also meet contact impedance requirements.

Although the disclosure has been described in considerable detail with reference to specific embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structures of the disclosure without departing from the scope or spirit of the disclosure. In view of the above, this disclosure is intended to cover modifications and variations of this disclosure so long as they come within the scope of the following claims.

Claims (13)

A touch sensor having a visible area and a peripheral area on at least one side of the visible area,
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;
a metal layer arranged on the substrate in correspondence with the peripheral region;
A portion of the metal layer overlaps and contacts at least a portion of the second portion of the metal nanowire layer to form an overlap region, and the contact area of the overlap region is 0.09 mm ² to 1.20 mm ² . and the contact impedance of the overlapping region is less than 50Ω.
touch sensor. 2. The touch sensor of claim 1, wherein the contact area is the vertical projected area of the overlap region on the substrate. The touch sensor according to claim 1 or 2, wherein the contact area is between 0.09 mm ² and 0.60 mm ² . The touch sensor according to any one of claims 1-3, wherein the contact impedance is less than 40Ω. said metal nanowire layer comprising a matrix, a plurality of first metal nanowires and a plurality of second metal nanowires, each of said first metal nanowires being completely embedded within said matrix; The touch sensor of any one of claims 1-4, wherein each of said second metal nanowires is partially embedded within said matrix. each of the second metal nanowires in the second portion of the metal nanowire layer has a first portion embedded within the matrix and a second portion protruding from a top surface of the matrix; 6. The touch sensor of claim 5, wherein said second portion of said second metal nanowires is embedded within said metal layer. 6. The touch sensor of claim 5, wherein each of said second metal nanowires has a first portion embedded within said matrix and a second portion protruding from a top surface of said matrix. The metal nanowire layer further comprises a plurality of first film structures and a plurality of second film structures,
each of the first membrane structures disposed at an interface between the matrix and each of the first metal nanowires;
each of the second membrane structures is disposed at an interface between the matrix and the first portion of each of the second metal nanowires;
The touch sensor according to claim 6 or 7. Each of the first film structures covers each of the first metal nanowires to form a first covering structure, and each of the second film structures covers each of the second metal nanowires. 9. The touch sensor of claim 8, covering the first portion and forming a second covering structure. The touch of any one of the preceding claims, wherein the first portion of the metal nanowire layer constitutes a touch sensing electrode and the second portion of the metal layer constitutes a peripheral circuit. sensor. A method of manufacturing a touch sensor having a visible area and a peripheral area on at least one side of the visible area, comprising:
preparing a substrate;
forming a metal nanowire layer corresponding to the visible region and the peripheral region on the substrate;
a step of surface-treating the metal nanowire layer;
forming a metal layer corresponding to the peripheral region on the substrate;
A portion of the metal layer overlaps and contacts the surface-treated metal nanowire layer to form an overlap region, and the contact area of the overlap region is 0.09 mm ² to 1.20 mm ² . , the contact impedance of the overlapping region is less than 50Ω;
A method for manufacturing a touch sensor. The step of performing the surface treatment on the metal nanowire layer includes:
A step of subjecting the metal nanowire layer to a vacuum plasma treatment,
12. The method of manufacturing a touch sensor according to claim 11, wherein the vacuum plasma treatment is performed with argon plasma having an output of 2 kW to 8 kW and a flow rate of 1500 sccm to 2500 sccm, and the time of the vacuum plasma treatment is 20 minutes to 30 minutes. the metal nanowire layer includes a matrix, a plurality of metal nanowires, and a plurality of film structures;
each of the metal nanowires has a first portion embedded in the matrix and a second portion protruding from the top surface of the matrix;
each of the membrane structures covering each of the metal nanowires;
The step of performing the surface treatment on the metal nanowire layer includes the film structure covering the second portion of each of the metal nanowires such that the second portion of each of the metal nanowires is exposed. 13. The method of manufacturing a touch sensor according to claim 11 or 12, comprising removing each of the .

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