CN114385020B

CN114385020B - Touch panel and touch device

Info

Publication number: CN114385020B
Application number: CN202011129434.3A
Authority: CN
Inventors: 余建贤; 丁紫君; 徐雲国; 方建华; 吕力锝
Original assignee: TPK Advanced Solutions Inc
Current assignee: TPK Advanced Solutions Inc
Priority date: 2020-10-21
Filing date: 2020-10-21
Publication date: 2024-04-19
Anticipated expiration: 2040-10-21
Also published as: KR20220052807A; KR102445009B1; CN114385020A; JP7036963B1; JP2022068084A

Abstract

A touch panel and a touch device are provided, wherein the touch panel comprises a substrate, a bulge structure, a touch sensing electrode layer and a peripheral circuit layer. The substrate is provided with a visible area and a frame area surrounding the visible area. The bump structure is arranged on the substrate and is positioned in the frame area, wherein the bump structure and the substrate form a level difference area. The touch sensing electrode layer is arranged in the visible area and extends to the frame area partially to span the bulge structure and cover the level difference area. The peripheral circuit layer is arranged in the frame area and is at least overlapped on the bulge structure and the step area with the touch sensing electrode layer. Therefore, the electrical lap joint stability between the touch sensing electrode layer and the peripheral circuit layer can be improved, and the requirements of users on narrow-frame products are further met.

Description

Touch panel and touch device

Technical Field

The present disclosure relates to a touch panel and a touch device, and more particularly, to a touch panel and a touch device with overlapping structures.

Background

In recent years, portable electronic products such as mobile phones, notebook computers, satellite navigation systems, and digital video players have widely used touch panels as a communication channel between users and electronic devices.

The touch panel includes touch electrodes and peripheral circuits, and the touch electrodes and the peripheral circuits are generally overlapped with each other in a peripheral area to form a conductive path or loop, wherein an overlap impedance value affects signal transmission and reaction rate of the touch panel, and the overlap impedance value depends on an overlap area between the touch electrodes and the peripheral circuits. Generally, when the overlap area is larger, the overlap impedance value is smaller, but the overlap area also directly affects the size of the peripheral area of the touch panel, so as to gradually increase the demand for narrow-frame products in the market, and providing a touch panel that can meet the size of the peripheral area and the demand for the overlap impedance value is a current direction worthy of research.

Disclosure of Invention

According to some embodiments of the present disclosure, a touch panel includes a substrate, a bump structure, a touch sensing electrode layer, and a peripheral circuit layer. The substrate is provided with a visible area and a frame area surrounding the visible area. The bump structure is arranged on the substrate and is positioned in the frame area, wherein the bump structure and the substrate form a level difference area. The touch sensing electrode layer is arranged in the visible area and extends to the frame area partially to span the bulge structure and cover the level difference area. The peripheral circuit layer is arranged in the frame area and is at least overlapped on the bulge structure and the step area with the touch sensing electrode layer.

In some embodiments, the touch sensing electrode layer includes a substrate and a plurality of metal nanostructures distributed in the substrate.

In some embodiments, the bump structure is formed of a metal material, and the metal material has an activity greater than that of the metal nanostructure.

In some embodiments, the raised structure has a central region and a peripheral region surrounding the central region, and the vertical thickness of the central region is greater than the vertical thickness of the peripheral region.

In some embodiments, the touch sensing electrode layer has a first portion and a second portion, the first portion covers a central region of the bump structure, the second portion covers a peripheral region and a step region of the bump structure, and the first portion is connected to the second portion.

In some embodiments, the second portion of the touch sensing electrode layer is in contact with the substrate in the level difference region.

In some embodiments, the touch sensing electrode layer includes a plurality of metal nanostructures, and the density of the metal nanostructures in the second portion of the touch sensing electrode layer is greater than the density in the first portion of the touch sensing electrode layer.

In some embodiments, the density of the metal nanostructures in the first portion of the touch-sensitive electrode layer is between 10% and 50%, and the density of the metal nanostructures in the second portion of the touch-sensitive electrode layer is increased by between 7% and 18% compared to the density in the first portion of the touch-sensitive electrode layer.

In some embodiments, the maximum vertical thickness of the raised structures is between 2 μm and 8 μm.

In some embodiments, the substrate is a protective cover plate and the raised structure is at least a portion of a light shielding structure.

In some embodiments, the touch sensing electrode layer conformally extends over the bump structure.

In some embodiments, the overlapping area of the touch sensing electrode layer and the peripheral circuit layer defines a lap joint area.

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

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

According to the above embodiments of the disclosure, since the touch panel of the disclosure has the bump structure disposed between the substrate and the touch sensing electrode layer, the overlap area between the touch sensing electrode layer and the peripheral circuit layer is increased, so that the overlap impedance between the touch sensing electrode layer and the peripheral circuit layer is reduced. Therefore, the electrical lap joint stability between the touch sensing electrode layer and the peripheral circuit layer can be improved, so that the lateral space required by lap joint is reduced, and the lateral width of the frame area of the touch panel is reduced, so that the requirement of a user on a narrow frame product is met.

Drawings

The foregoing and other objects, features, advantages and embodiments of the present disclosure will be apparent from the following description of the drawings in which:

FIG. 1 is a schematic top view of a touch panel according to an embodiment of the disclosure;

Fig. 2 is a schematic enlarged partial view of a region R1 of the touch panel of fig. 1; and

Fig. 3 is a schematic cross-sectional view of the touch panel of fig. 2 taken along line a-a'.

[ Symbolic description ]

100 Touch panel

110 Substrate

111 Top surface

120 Bump structure

121 Top surface

122 Central region

124 Peripheral region

130 Touch sensing electrode layer

131 Top surface

132 First part

134 Second part

136 Matrix

138 Metal nanowire

140 Peripheral circuit layer

143 Bottom surface

200 Overlap joint structure

S, section difference area

VR viewing area

BR frame region

W1 width

W2 lateral width

T1, T2, T3, T4 thickness

T _M maximum vertical thickness

X, Y, Z axis

Length of L1

A-a' line segment

Detailed Description

Various embodiments of the present disclosure are disclosed in the accompanying drawings, and for purposes of explanation, numerous practical details are set forth in the following description. However, it should be understood that these practical details are not to be used to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary and therefore should not be used to limit the present disclosure. Furthermore, for the purpose of simplifying the drawings, some known and conventional structures and elements are shown in the drawings in a simplified schematic manner. In addition, the dimensions of the various elements in the drawings are not drawn to scale for the convenience of the reader.

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

The disclosure provides a touch panel having a bump structure disposed between a substrate and a touch sensing electrode layer. Through the arrangement of the bulge structure, the electrical lap joint stability between the touch sensing electrode layer and the peripheral circuit layer can be improved, and the lateral width of the frame area of the touch panel can be further reduced, so that the requirement of a user on a narrow-frame product can be met.

Fig. 1 is a schematic top view of a touch panel 100 according to an embodiment of the disclosure, fig. 2 is a schematic enlarged partial view of a region R1 of the touch panel 100 of fig. 1, and fig. 3 is a schematic cross-sectional view of the touch panel of fig. 2 along a line a-a'. Referring to fig. 1 to 3, the touch panel 100 includes a substrate 110, a bump structure 120, a touch sensing electrode layer 130, and a peripheral circuit layer 140. The substrate 110 extends along a horizontal plane (e.g., a plane formed by an X-axis and a Y-axis) and has a viewing region VR and a frame region BR surrounding the viewing region VR. Although the touch sensing electrode layer 130 of the present embodiment is only represented by the X-axis electrode, in practical design, the touch sensing electrode layer 130 may further include the Y-axis electrode. In addition, the electrode pattern of the touch sensing electrode layer 130 is not limited in the disclosure.

In some embodiments, the substrate 110 may be, for example, a hard transparent substrate or a flexible transparent substrate. 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 the like, or a combination thereof. In some embodiments, a pretreatment step may be performed on the surface of the substrate 110, for example, a surface modification process is performed or an adhesive layer or a resin layer is additionally coated on the surface of the substrate 110 to improve the adhesion between the substrate 110 and other layers (e.g., the bump structure 120 and/or the touch sensing electrode layer 130 above the substrate 110).

In some embodiments, the bump structure 120 is disposed on the substrate 110 and located in the frame region BR, wherein the bump structure 120 is vertically (e.g. along the Z-axis direction) bump and forms a step region S with the substrate 110 due to a height difference. The touch sensing electrode layer 130 is disposed on the substrate 110 and located in the visible region VR, and extends partially to the frame region BR to span the bump structure 120 and cover the level difference region S. The peripheral circuit layer 140 is disposed on the substrate 110, is located in the frame region BR, and overlaps the touch sensing electrode layer 130 at least on the bump structure 120 and the step region S. In some embodiments, the bump structure 120, the touch sensing electrode layer 130 and the peripheral circuit layer 140 are sequentially stacked over the substrate 110 to form a bonding structure 200 located in the frame region BR.

In some embodiments, the overlapping area of the touch sensing electrode layer 130 and the peripheral circuit layer 140 defines a lap area, and the lap area has a lap area. In the present embodiment, the overlapping region of the touch sensing electrode layer 130 and the peripheral circuit layer 140 is a quadrangular overlapping region in a plan view (i.e., a view in fig. 2). More specifically, the lap zone of the present embodiment is a quadrangular region formed by a length L1 and a width W1 in a plan view.

When the touch panel 100 is in operation, the touch sensing electrode layer 130 located in the visual area VR can sense the touch action of the user to generate a touch sensing signal, and the touch sensing signal can be further transmitted to the peripheral circuit layer 140 located in the frame area BR through the lap joint contact of the touch sensing electrode layer 130 and the peripheral circuit layer 140 in the lap joint structure 200 for subsequent signal processing. In the following description, the lap joint structure 200 of the present disclosure will be described in more detail.

It should be understood that the cross section taken along the line a-a' in fig. 3 is the cross section of the bridging structure 200 of the present disclosure, that is, fig. 3 is a schematic cross section of the bridging structure 200 in the touch panel 100 of fig. 2. Referring to fig. 3, in some embodiments, the bump structure 120 has a central region 122 and a peripheral region 124 surrounding the central region 122, and the thickness (also referred to as vertical thickness) T1 of the central region 122 along the Z-axis is greater than the thickness (also referred to as vertical thickness) T2 of the peripheral region 124 along the Z-axis. For example, in the embodiment of fig. 3, the thickness of the bump structure 120 decreases from the central region 122 to the peripheral region 124, and the decrease in thickness increases from the central region 122 to the peripheral region 124. Such thickness variations may cause the upper surface of the raised structure 120 to present a convex arc (convex) surface. In some embodiments, the maximum vertical thickness T _M of the bump structure 120 may be between 2 μm and 8 μm to improve the electrical bonding stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140, and further reduce the lateral width W2 of the frame region BR of the touch panel 100 (as will be described in more detail below). In some embodiments, the top surface 121 of the bump structure 120 may be rounded, for example (as shown in fig. 3). In other embodiments, the top surface 121 of the ridge structure 120 may be, for example, a regular/irregular shaped surface, such as a stepped or wavy shape. It should be understood that regardless of the profile of the top surface 121 of the bump structure 120, it is within the scope of the disclosure that the vertical thickness T1 of the central region 122 of the bump structure 120 is greater than the vertical thickness T2 of the peripheral region 124. In some embodiments, when the substrate 110 is configured to serve as a protective cover for the touch panel 100, the bump structure 120 may be at least a portion of a light shielding structure of the touch panel 100, and may be formed of a dark or opaque photoresist, for example.

In some embodiments, the touch sensing electrode layer 130 spans the entire bump structure 120 laterally, e.g., along the X-axis direction. In other words, in the overlap structure 200, the vertical projection of the touch sensing electrode layer 130 on the substrate 110 can, for example, completely cover the vertical projection of the bump structure 120 on the substrate 110. Specifically, in the overlap structure 200, the touch sensing electrode layer 130 has a first portion 132 and a second portion 134 laterally surrounding the first portion 132, where the first portion 132 covers the central region 122 of the bump structure 120, the second portion 134 covers the peripheral region 124 and the level difference region S of the bump structure 120, the first portion 132 is connected to the second portion 134, and the highest position (e.g., the top surface) of the first portion 132 is higher than the highest position of the second portion 134. In addition, the second portion 134 of the touch sensing electrode layer 130 contacts the substrate 110 in the level difference region S.

In some embodiments, the touch sensing electrode layer 130 on the bump structure 120 may undulate with the contour of the top surface 121 of the bump structure 120. In other words, in the overlap structure 200, the contour of the touch sensing electrode layer 130 may depend on the contour of the top surface 121 of the bump structure 120. In some embodiments, the touch sensing electrode layer 130 may conformally (conformally) extend over the bump structure 120 and the substrate 110, i.e., in the overlap structure 200, the touch sensing electrode layer 130 may have a uniform and consistent thickness T3 with respect to the top surface 121 of the bump structure 120, and the touch sensing electrode layer 130 contacting the substrate 110 may also have a uniform and consistent thickness T3 with respect to the top surface 111 of the substrate 110. In some embodiments, the thickness T3 of the touch sensing electrode layer 130 may be between 30nm and 120nm, so that the touch sensing electrode layer 130 and the peripheral circuit layer 140 can maintain the required electrical bonding stability and avoid affecting the optical effect. In detail, when the thickness T3 of the touch sensing electrode layer 130 is less than 30nm, the signal transmission may be affected due to the excessive surface resistance value; when the thickness T3 of the touch sensing electrode layer 130 is greater than 120nm, the optical effect may be affected.

In some embodiments, the touch sensing electrode layer 130 may include a matrix 136 and a plurality of metal nanowires (also referred to as metal nanostructures) 138 distributed in the matrix 136. In some embodiments, the matrix 136 may include a polymer or a mixture thereof, thereby imparting specific chemical, mechanical, and optical properties to the touch sensing electrode layer 130. For example, the matrix 136 may provide adhesion between the touch sensing electrode layer 130 and the bump structure 120 and between the touch sensing electrode layer 130 and the substrate 110. For another example, the substrate 136 may provide good mechanical strength to the touch sensing electrode layer 130. In some embodiments, the matrix 136 may include a specific polymer to provide the touch sensing electrode layer 130 with additional scratch/abrasion surface protection, thereby improving the surface strength of the touch sensing electrode layer 130. The specific polymer may be, for example, a polyacrylate, an epoxy, a poly (silicon-acrylic), a polyurethane, a polysilicone, a polysilane, or a combination of any of the foregoing. In some embodiments, the substrate 136 may further include a cross-linking agent, a polymerization inhibitor, a stabilizer (including, but not limited to, an antioxidant or an ultraviolet stabilizer), a surfactant, or any combination thereof, to enhance the ultraviolet resistance and extend the service life of the touch sensing electrode layer 130.

In some embodiments, the metal nanowires 138 may include, but are not limited to, nano-silver wires (silver nanowire), nano-gold wires (gold nanowire), nano-copper wires (copper nanowire), nano-nickel wires (nickel nanowire), or any combination of the above. In more detail, the term "metal nanowire 138" is a collective term that refers to a collection of metal wires comprising a plurality of metal elements, metal alloys, or metal compounds (including metal oxides). In some embodiments, the cross-sectional dimension (i.e., the diameter of the cross-section) of the single metal nanowire 138 may be less than 500nm, preferably may be less than 100nm, and more preferably may be less than 50nm. In some embodiments, the metal nanowires 138 have a large aspect ratio. Specifically, the aspect ratio of the metal nanowires 138 may be between 10 and 100000. In more detail, the aspect ratio of the metal nanowires 138 may be greater than 10, preferably greater than 50, and more preferably greater than 100. In addition, other terms such as silk, fiber, tube, etc. having the cross-sectional dimensions and aspect ratios described above are also within the scope of the present disclosure.

In some embodiments, the peripheral circuit layer 140 on the bump structure 120 laterally spans the touch sensing electrode layer 130, for example, along the X-axis direction. In other words, in the bonding structure 200, the peripheral circuit layer 140 may be located directly above the touch sensing electrode layer 130 and cover the touch sensing electrode layer 130, so as to electrically bond with the touch sensing electrode layer 130. Through the electrical overlap between the touch sensing electrode layer 130 and the peripheral circuit layer 140, the touch sensing signal can be transmitted in the touch panel 100 without obstruction. In some embodiments, the bottom surface 143 of the peripheral circuit layer 140 may undulate with the contour of the top surface 131 of the touch sensing electrode layer 130, i.e. the contour of the bottom surface 143 of the peripheral circuit layer 140 may depend on the contour of the top surface 131 of the touch sensing electrode layer 130. In some embodiments, the peripheral wiring layer 140 may have a vertical thickness T4 that varies with position. In detail, the vertical thickness T4 of the peripheral circuit layer 140 may gradually increase from the center of the bonding structure 200 to the periphery. In other embodiments, the peripheral circuit layer 140 may also have a uniform and consistent thickness T4 on the area corresponding to the bump structure 120 with respect to the top surface 131 of the touch sensing electrode layer 130. In some embodiments, the peripheral circuitry layer 140 may include, for example, copper, silver, copper-silver alloy, or other suitable conductive material.

In some embodiments, the electrical overlap stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 may depend on the physical characteristics (e.g., shape and vertical thickness, etc.) of the bump structure 120. In other words, by adjusting the physical characteristics of the bump structure 120, the electrical lap joint stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 can be improved. Specifically, when the touch sensing electrode layer 130 is disposed on the bump structure 120, since the bump structure 120 has a structure with a convex middle, the touch sensing electrode layer 130 may be formed into a shape similar to an arch bridge, so as to increase an actual overlapping area on the premise that a size of an overlapping area (e.g., a length L1 and a width W1 of the overlapping area) formed between the touch sensing electrode layer 130 and the peripheral circuit layer 140 is unchanged, and the metal nanowires 138 in the touch sensing electrode layer 130 may be settled and accumulated in the step area S due to the gravity. In this way, the overlap impedance value between the touch sensing electrode layer 130 (especially the second portion 134 of the touch sensing electrode layer 130) and the peripheral circuit layer 140 can be reduced, so as to improve the electrical overlap stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140.

As described above, since the maximum vertical thickness T _M of the bump structure 120 can be between 2 μm and 8 μm, the electrical bonding stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 can be improved, and the lateral width W2 of the frame region BR of the touch panel 100 can be further reduced. In detail, when the touch sensing electrode layer 130 is disposed on the bump structure 120, if the maximum vertical thickness T _M of the bump structure 120 is smaller than 2 μm, the touch sensing electrode layer 130 cannot form a shape similar to an arch bridge, but still is disposed on the substrate 110 approximately in a plane, so that the overlap area of the touch sensing electrode layer 130 and the peripheral circuit layer 140 cannot be effectively increased, and the metal nanowires 138 cannot be properly settled and aggregated, and further the overlap impedance value between the touch sensing electrode layer 130 and the peripheral circuit layer 140 cannot meet the design requirement, so that only a larger overlap area can be designed to increase the overlap area, and the lateral width W2 of the border region BR of the touch panel 100 cannot be reduced; however, when the touch sensing electrode layer 130 is disposed on the bump structure 120, if the maximum vertical thickness T _M of the bump structure 120 is greater than 8 μm, the metal nanowires 138 may excessively settle in the touch sensing electrode layer 130, so that the electrical overlap between the first portion 132 of the touch sensing electrode layer 130 and the peripheral circuit layer 140 is unstable, and the touch sensing electrode layer 130 needs to climb to a higher height to easily generate electrical failure.

Since the metal nanowires 138 in the touch sensing electrode layer 130 are subject to the physical characteristics of the bump structure 120 to settle and accumulate in the second portion 134 of the touch sensing electrode layer 130, the metal nanowires 138 in the second portion 134 of the touch sensing electrode layer 130 may have a greater density relative to the metal nanowires 138 in the first portion 132 of the touch sensing electrode layer 130. It should be appreciated that the term "density" as used herein refers to the number of metal nanowires 138 included in a unit area of the touch sensing electrode layer 130. In some embodiments, the density of the metal nanowires 138 in the first portion 132 of the touch sensing electrode layer 130 may be between 10% and 50%, and preferably between 12% and 22% if the optical and electrical effects are desired, while the density of the metal nanowires 138 in the second portion 134 of the touch sensing electrode layer 130 may be increased by about 7% to 18% compared to the density of the metal nanowires 138 in the first portion 132. In this way, the touch sensing electrode layer 130 can be ensured to have good conductivity, so that the touch sensing electrode layer 130 and the peripheral circuit layer 140 have good electrical lap joint stability. In detail, the above density will affect the surface resistance of the touch sensing electrode layer 130 and the appearance optical effect of the entire touch panel 100. If the density is small, i.e. the metal nanowires 138 are sparse in the matrix 136, then the surface resistance is easily excessive; if the density is too high, i.e., the metal nanowires 138 are denser in the matrix 136, the light transmittance is reduced, which affects the optical effect. It should be appreciated that the aforementioned optical effects refer to the optical effects of the visible region VR, because the touch sensing electrode layer 130 located in the visible region VR and the touch sensing electrode layer 130 extending to the frame region BR are formed by being coated entirely during the manufacturing process, the density of the metal nanowires 138 in the touch sensing electrode layer 130 located in the frame region BR (especially the density of the metal nanowires 138 in the first portion 132 of the touch sensing electrode layer 130) is substantially similar to the density of the metal nanowires 138 in the touch sensing electrode layer 130 located in the visible region VR, and therefore, the optical effects of the visible region VR of the touch panel 100 should be considered indirectly when the density of the metal nanowires 138 in the touch sensing electrode layer 130 located in the frame region BR is considered in the design of the whole coated touch sensing electrode layer 130. On the other hand, the bump structure 120 can be formed by selecting a metal material (e.g. copper) with a conductivity greater than that of the metal nanowire 138, so that the overall electrical bonding stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 can be improved due to the bump structure 120 of the metal material.

In some embodiments, the electrical overlap stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 may further depend on the chemical characteristics (e.g., materials) of the bump structure 120. In other words, by adjusting the chemical characteristics of the bump structure 120, the electrical bonding stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140 can be further improved. More specifically, the bump structure 120 is formed by selecting a metal material with an activity (or chemical reactivity) greater than that of the metal nanowire 138, so that the metal nanowire 138 is more likely to be gathered in the touch sensing electrode layer 130 between the peripheral circuit layer 140 and the bump structure 120, and further, the density of the metal nanowire 138 in the touch sensing electrode layer 130 of the overlap structure 200 is improved, so as to improve the electrical overlap stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140. For example, when nano-silver wire is selected as the metal nanowire 138, a metal having a higher activity than silver (e.g., copper) may be selected as the material of the bump structure 120.

In more detail, the touch sensing electrode layer 130 may be formed by coating, curing, and drying the dispersion including the metal nanowires 138. In some embodiments, the dispersion includes a solvent, thereby uniformly dispersing the metal nanowires 138 therein. Specifically, the solvent is, for example, water, alcohols, ketones, ethers, hydrocarbons, aromatic solvents (benzene, toluene, xylene, or the like), or any combination of the above. In some embodiments, the dispersion may further include additives, surfactants, and/or binders, thereby improving the compatibility between the metal nanowires 138 and the solvent and the stability of the metal nanowires 138 in the solvent. Specifically, the additive, surfactant, and/or binder may be, for example, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, sulfonate, sulfate, phosphate, disulfonate, sulfosuccinate, fluorosurfactant, or a combination of any of the foregoing.

First, the coating step may include, for example, but not limited to, screen printing, spray coating, or roller coating processes. In some embodiments, a roll-to-roll (roll-to-roll) process may be used to uniformly apply the dispersion including the metal nanowires 138 to the top surface 111 of the substrate 110 and the top surface 121 of the bump structure 120. Since the bump structure 120 has a structure of a middle bump, the metal nanowires 138 in the dispersion liquid that has not been dried may be settled due to the effect of gravity and partially aggregated in the dispersion liquid near the level difference region S. Meanwhile, if the activity of the material of the bump structure 120 is greater than that of the metal nanowire 138, the metal nanowire 138 in the dispersion may be also affected by the material of the bump structure 120 to be gathered relatively near the surface of the bump structure 120. In other words, the metal nanowires 138 in the dispersion coated on the periphery of the overlap 200 (e.g., in the visible region VR shown in fig. 2) may slightly move and partially accumulate at positions corresponding to the surfaces contacting the overlap 200. Then, a curing and drying molding step is performed, so that the metal nanowires 138 can be fixed on the top surface 111 of the substrate 110 and the top surface 121 of the bump structure 120, thereby forming the touch sensing electrode layer 130.

In general, since the metal nanowires 138 in the dispersion liquid are moved and gathered at specific positions under the influence of the physical properties (e.g., vertical thickness, shape, conductivity, etc.) and chemical properties (e.g., materials) of the bump structure 120 in the above-mentioned coating step, the metal nanowires 138 are more densely distributed in the touch sensing electrode layer 130 in the overlap structure 200 after the curing and drying forming steps are performed, and in particular, the touch sensing electrode layer 130 is correspondingly located in the second portion 134 of the step region S. In this way, the overlap impedance value between the touch sensing electrode layer 130 (especially the second portion 134 of the touch sensing electrode layer 130) and the peripheral circuit layer 140 can be reduced, so as to improve the electrical overlap stability between the touch sensing electrode layer 130 and the peripheral circuit layer 140.

In some embodiments, a primer layer may be applied to the metal nanowires 138 affixed to the substrate 110 and the bump structures 120 and cured such that the primer layer and the metal nanowires 138 form a composite structural layer. In other words, the cured primer layer is the substrate 136 of the present disclosure, and the composite structural layer is the touch sensing electrode layer 130 of the present disclosure. In detail, the aforementioned polymer or mixture thereof may be molded on the metal nanowires 138 in a coating manner, and then the polymer or mixture thereof may be infiltrated between the metal nanowires 138 to form a filler, and cured to form the matrix 136. As such, the metal nanowires 138 may be embedded in the matrix 136. In some embodiments, primer layers having the above-described polymers or mixtures thereof may be formed into the substrate 136 using a heated bake. In some embodiments, the temperature of the heated bake may be between 60 ℃ and 150 ℃. It should be appreciated that the physical structure between the substrate 136 and the metal nanowires 138 is not intended to limit the present disclosure. In some embodiments, the matrix 136 and the metal nanowires 138 may be a stack of two-layer structures. In other embodiments, the matrix 136 and the metal nanowires 138 may be intermixed to form a composite structural layer. In a preferred embodiment, metal nanowires 138 are embedded in matrix 136 to form a composite structural layer.

The touch panel 100 of the present disclosure may be assembled with other electronic devices or further integrated into a touch device, such as a display with touch function. For example, the touch panel 100 may be attached to a display element (e.g., a liquid crystal display element or an organic light emitting diode display element), and the two may be attached using an optical adhesive or other adhesive. The touch panel 100 of the present disclosure may be applied to electronic devices such as a portable phone, a tablet computer, and a notebook computer, and may also be applied to flexible products. The touch panel 100 of the present disclosure may also be applied to a polarizer. The touch panel 100 of the present disclosure may also be applied to wearable devices (e.g., watches, glasses, etc.) and vehicular devices (e.g., dashboards, automobile recorders, automobile rearview mirrors, windows, etc.).

Since the touch panel disclosed by the invention has the bump structure arranged between the substrate and the touch sensing electrode layer, the overlap area of the touch sensing electrode layer and the peripheral circuit layer is increased, and the overlap impedance value between the touch sensing electrode layer and the peripheral circuit layer is reduced. Therefore, the electrical lap joint stability between the touch sensing electrode layer and the peripheral circuit layer can be improved, so that the lateral space required by lap joint is reduced, and the lateral width of the frame area of the touch panel is reduced, thereby meeting the requirements of users on narrow-frame products.

While the present disclosure has been described with reference to the exemplary embodiments, it should be understood that the invention is not limited thereto, but may be variously modified and modified by those skilled in the art without departing from the spirit and scope of the present disclosure, and thus the scope of the present disclosure is defined by the appended claims.

Claims

1. A touch panel, comprising:

a substrate having a visual area and a frame area surrounding the visual area;

The raised structure is arranged on the substrate and positioned in the frame area, wherein the raised structure and the substrate form a level difference area, the raised structure is provided with a central area and a peripheral area surrounding the central area, and the vertical thickness of the central area is larger than that of the peripheral area;

The touch sensing electrode layer is arranged in the visible area, extends to the frame area partially to cross the raised structure and cover the level difference area, and is provided with a first part and a second part, wherein the first part covers the central area of the raised structure, the second part covers the peripheral area of the raised structure and the level difference area, and the first part is connected with the second part; and

The peripheral circuit layer is arranged in the frame area and is at least overlapped with the touch sensing electrode layer on the raised structure and the level difference area, the raised structure, the touch sensing electrode layer and the peripheral circuit layer are sequentially stacked above the substrate, a bottom surface of the peripheral circuit layer is fluctuated along with the outline of a top surface of the touch sensing electrode layer, and an overlap area is defined by the overlapping area of the touch sensing electrode layer and the peripheral circuit layer.

2. The touch panel of claim 1, wherein the touch sensing electrode layer comprises a matrix and a plurality of metal nanostructures distributed in the matrix.

3. The touch panel of claim 2, wherein the bump structure is formed of a metal material having an activity greater than that of the plurality of metal nanostructures.

4. The touch panel of claim 1, wherein the second portion of the touch sensing electrode layer contacts the substrate in the level difference region.

5. The touch panel of claim 1, wherein the touch sensing electrode layer comprises a plurality of metal nanostructures, and wherein a density of the plurality of metal nanostructures in the second portion of the touch sensing electrode layer is greater than a density in the first portion of the touch sensing electrode layer.

6. The touch panel of claim 5, wherein a density of the plurality of metal nanostructures in the first portion of the touch-sensing electrode layer is between 10% and 50%, and a density of the plurality of metal nanostructures in the second portion of the touch-sensing electrode layer is increased by between 7% and 18% compared to a density in the first portion of the touch-sensing electrode layer.

7. The touch panel of claim 1, wherein the bump structure has a maximum vertical thickness of between 2 μm and 8 μm.

8. The touch panel of claim 1, wherein the substrate is a protective cover and the bump structure is at least a portion of a light shielding structure.

9. The touch panel of claim 1, wherein the touch sensing electrode layer conformally extends over the bump structure, wherein the touch sensing electrode layer has a uniform and consistent thickness with respect to a top surface of the bump structure, and wherein the touch sensing electrode layer in contact with the substrate also has a uniform and consistent thickness with respect to a top surface of the substrate.

10. A touch device comprising the touch panel of claim 1.

11. The touch device of claim 10, wherein the touch device comprises a display, a portable phone, a notebook computer, a tablet computer, a wearable device, a vehicular device, or a polarizer.