WO2021134603A1

WO2021134603A1 - Transparent conductive thin film, touch sensor and touch screen

Info

Publication number: WO2021134603A1
Application number: PCT/CN2019/130790
Authority: WO
Inventors: 喻文志; 候晓伟; 李磊涛
Original assignee: 南昌欧菲显示科技有限公司
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-08

Abstract

A transparent conductive thin film. A plurality of base material layers are bonded by means of a flexible adhesive layer to form a substrate having a multi-layer composite structure, thus the thickness of a single base material layer can be significantly reduced while ensuring the supporting strength of the substrate, and therefore each base material layer has better flexibility and is more resistant to bending. Moreover, a flexible adhesive layer exists between adjacent base material layers, and the flexible adhesive layer not only can achieve a bonding effect, but also can achieve the effect of stress absorbing. Therefore, the substrate can be subjected to fold for multiple times without generating irreversible deformation, thereby improving the bending resistance performance of the described transparent conductive thin film. In addition, further provided are a sensor and a touch screen.

Description

Transparent conductive film, touch sensor and touch screen

Technical field

The invention relates to the technical field of conductive films, in particular to a transparent conductive film, a touch sensor and a touch screen.

Background technique

Transparent conductive films are widely used in solar cells, touch screens and other fields. With the continuous exploration of user needs, foldable touch solutions have emerged. In the existing transparent conductive film, in order to ensure sufficient support strength, the substrate needs to have a relatively large thickness, generally greater than 40 microns. As a result, the flexibility of the substrate becomes smaller, and it will be difficult to recover after many times of folding, resulting in poor winding resistance of the transparent conductive film.

Summary of the invention

According to various embodiments of the present application, a transparent conductive film, a touch sensor, and a touch screen are provided.

A transparent conductive film, including:

The substrate includes two laminated substrate layers and a flexible adhesive layer located between the two substrate layers, the two substrate layers are bonded by the flexible adhesive layer, and the substrate The outermost layer is the substrate layer;

A transparent conductive layer formed on at least one surface of the substrate;

The metal layer is arranged on the side of the transparent conductive layer away from the substrate.

A touch sensor, the touch sensor is made of the transparent conductive film according to any one of the above preferred embodiments, the touch sensor includes a touch area and a lead area, and the metal layer is located on the The lead area, the touch area includes an electrode etched from the transparent conductive layer, and the lead area includes a lead etched from the metal layer and the transparent conductive layer located in the lead area.

A touch screen includes the touch sensor as described in the above embodiment.

The details of one or more embodiments of the present invention are set forth in the following drawings and description. Other features, objects and advantages of the present invention will become apparent from the description, drawings and claims.

Description of the drawings

Figure 1 is a schematic diagram of the structure of a transparent conductive film in a preferred embodiment of the utility model;

2 is a schematic diagram of the structure of the substrate in the transparent conductive film shown in FIG. 1;

FIG. 3 is a schematic diagram of the structure of the touch sensor in the preferred embodiment of the present invention.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or a central element may also be present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or an intermediate element may be present at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

Please refer to FIG. 1, the transparent conductive film in the preferred embodiment of the present invention includes a substrate 11, a transparent conductive layer 12 and a metal layer 13.

The substrate 11 plays a supporting role and is used to attach other film structures such as the transparent conductive layer 12 and the metal layer 13. The substrate 11 has two opposite surfaces, namely the upper surface and the lower surface shown in FIG. 1. Among them, the transparent conductive layer 12 and the metal layer 13 are sequentially formed on at least one surface of the substrate 11. That is, the above-mentioned transparent conductive film 10 may be a single-sided conductive film or a double-sided conductive film to be applied to GF and GFF touch screen solutions, respectively.

As shown in FIG. 1, specifically in this embodiment, a transparent conductive layer 12 and a metal layer 13 are formed on both surfaces of the substrate 11. At this time, the transparent conductive film 10 is a double-sided conductive film.

Obviously, in other embodiments, the transparent conductive layer 12 and the metal layer 13 may be sequentially formed only on the upper surface or the lower surface of the substrate 11 to form a single-sided conductive film.

Please also refer to FIG. 2, the substrate 11 includes two substrate layers 111 and a flexible adhesive layer 112, and the two substrate layers 111 are bonded by the flexible adhesive layer 112.

The substrate 11 has a "sandwich" structure. It can be understood that in other embodiments, the number of substrate layers 111 can also be increased according to requirements, and each time a substrate layer 111 is added, the number of flexible adhesive layers 112 is correspondingly increased by one.

The material of the substrate layer 111 can be COP (polycyclic olefin), PAR (polyarylate), PET (polyethylene terephthalate), PI (polyester imine), PEN (polyethylene naphthalate) Any one of organic polymer materials such as glycol ester), PC (polycarbonate), PMMA (polymethyl methacrylate), etc. In addition, the materials of the plurality of base material layers 111 in the same substrate 11 may be the same or different. In order to ensure the optical performance of the substrate 11, the in-plane phase difference of the substrate layer 111 in this embodiment is 20 nm or less when the wavelength is 590 nm.

Specifically, in this embodiment, the base layer 111 is a polycycloolefin layer. Cycloolefin polymer (COP) is a new type of amorphous polymer material with high hardness and excellent light transmittance, thereby significantly improving the optical performance of the substrate 111.

However, cycloolefin polymers are relatively brittle and are prone to scratches. Therefore, in this embodiment, the transparent conductive film 10 further includes a hard coat layer 14 and an optical adjustment layer 15 sandwiched between the substrate 11 and the transparent conductive layer 12, and the optical adjustment layer 15 is located on the hard coat layer 14 facing the transparent layer. One side of the conductive layer 12.

In other words, the hard coat layer 14 is attached to the surface of the base layer 111, and the hard coat layer 14 can protect the base layer 111, thereby improving its surface brittleness. The hard coat layer 14 generally contains a binder resin. This binder resin contains, for example, a curable resin composition based on ultraviolet rays and electron beams. The curable resin composition preferably contains a polymer obtained by an addition reaction of a glycidyl acrylate-based polymer and acrylic acid. Alternatively, the curable resin composition preferably contains a polyfunctional acrylate polymer (pentaerythritol, dipentaerythritol, etc.). The curable resin composition further contains a polymerization initiator.

Further, due to the increase of the film structure, the optical path deviation phenomenon caused by light refraction will be aggravated, and the optical adjustment layer 15 can be used to improve the refraction of light when passing through different film structures. Among them, the refractive index of the optical adjustment layer 15 is preferably set to a value between the refractive index of the substrate 11 and the refractive index of the transparent conductive layer 12. Therefore, it can play a transitional role in the propagation path of light. Specifically, the material forming the optical adjustment layer 15 is, for example, one or more of silicone polymers, acrylate polymers, aromatic ring or naphthalene ring polymers, zirconium oxide, titanium oxide, and antimony oxide.

The function of the flexible adhesive layer 112 is to bond the two substrate layers 111. Moreover, compared with the base material layer 111, the flexible adhesive layer 112 has a softer texture and higher flexibility. In this embodiment, the modulus of the substrate layer 111 is greater than 2000 MPa, and the modulus of the flexible adhesive layer 112 is less than 500 MPa. Therefore, the flexible adhesive layer 112 may be a colloidal material such as acrylic resin, light curing adhesive, pressure sensitive adhesive, etc. In order to ensure the optical performance of the substrate 11, the in-plane phase difference of the flexible adhesive layer 112 in this embodiment is less than 20 nanometers when the wavelength is 590 nanometers.

Specifically, in this embodiment, the flexible adhesive layer 112 is an optical adhesive layer. Optical glue has good bonding strength and high light transmittance. Therefore, the flexible adhesive layer 112 can not only play the role of bonding the substrate layer 111, but also improve the light transmittance and haze of the substrate 11 as a whole.

From the above description, it can be seen that the substrate 11 is a composite laminated structure composed of a plurality of base material layers 111 and a flexible adhesive layer 112. Therefore, under the premise of ensuring the support strength of the substrate 11, the thickness of each substrate layer 111 can be significantly reduced, so the flexibility of a single substrate layer 111 is significantly improved. After many times of bending, the substrate layer 111 will not be unable to be reset.

Further, the flexible adhesive layer 112 can also play a role of flexibly supporting the adjacent substrate layer 111 and absorbing stress. Therefore, the bending resistance of the substrate 111 is significantly improved, so the transparent conductive film 10 will also have better bending resistance.

In order to further improve the bending resistance performance of the transparent conductive film 10, in this embodiment, the transparent conductive layer 12 is a nano-silver wire conductive layer.

The nano silver wire conductive layer is formed by curing the nano silver wire. The nano silver wire conductive layer replaces the ITO layer in the traditional transparent conductive film, and is etched into a transparent electrode pattern when preparing the touch screen. Moreover, compared with the traditional ITO layer, the silver nanowire conductive layer has better flexibility, so it is more conducive to the bending of the transparent conductive film 10.

Obviously, in other embodiments, the transparent conductive layer 12 may also be in the form of ITO, metal mesh, or the like.

In addition, the metal layer 13 can also be made of a soft metal material. For example, copper, silver, etc.

In this embodiment, the thickness of each substrate layer 111 is 15 to 30 microns, and the thickness of each flexible adhesive layer 112 is 5 to 15 microns.

Specifically, when the thickness of the substrate layer 111 is greater than 30 μm, its thickness is too large, resulting in unsatisfactory bending resistance performance. When the thickness of the substrate layer 111 is less than 15 μm, the support strength of the substrate 11 is difficult to guarantee. When the thickness of the flexible adhesive layer 112 is greater than 15 micrometers, more water will be precipitated, which will result in poor crystallinity of the transparent conductive layer 12 and increase the haze of the substrate 11, and when the thickness of the flexible adhesive layer 112 is less than 5 micrometers , It is difficult to achieve better adhesion.

Further, specifically in this embodiment, the thickness of each substrate layer 111 is 25 micrometers, and the thickness of each flexible adhesive layer 112 is 10 micrometers.

With this thickness, the substrate 11 can maintain higher light transmittance, better bending resistance, and support strength that meets the requirements. Experiments show that the substrate 11 can withstand 200,000 bending tests.

In this embodiment, in the thickness direction of the substrate 11, the thickness of the plurality of base material layers 111 gradually increases or decreases.

In other words, the thickness of the multiple substrate layers 111 is not the same, and the thickness of the substrate layer 111 on one side of the substrate 11 (referred to as the first side) is greater than the thickness of the other side (referred to as the second side). small. In the actual application process, the transparent conductive film 10 generally only needs to be bent in a specific direction. Therefore, the bending direction of the transparent conductive film 10 can be set toward the first side described above.

Taking the example shown in FIG. 2 as an example, assuming that the bending direction of the transparent conductive film 10 is downward, the thickness of the base layer 111 of the lower layer is smaller than the thickness of the base layer 111 of the upper layer. In this way, the closer to the first side, the greater the deformation of the substrate layer 111 when the transparent conductive film 10 is bent; and the closer to the second side, the greater the deformation of the substrate layer 111 in the transparent conductive film 10 The smaller the deformation. Therefore, if the thickness of the base material layer 111 near the first side is set to be smaller, the larger bending requirement can be met while the overall thickness of the substrate 11 is further reduced. Setting the thickness of the base material layer 111 on the second side to be larger can ensure that the substrate 11 has sufficient support strength.

In the above-mentioned transparent conductive film 10, a plurality of substrate layers 111 are bonded by a flexible adhesive layer 112 to form a substrate 11 of a multilayer composite structure, so that the support strength of the substrate 11 is ensured, and the thickness of a single substrate layer 111 is It can also be significantly reduced, so each substrate layer 111 is more flexible and more resistant to bending. Moreover, there is a flexible adhesive layer 112 between adjacent substrate layers 111, and the flexible adhesive layer 112 can not only play a role in bonding, but also play a role in absorbing stress. Therefore, the substrate 11 can withstand multiple folding without irreversible deformation, thereby improving the bending resistance of the transparent conductive film 10 described above.

Please also refer to FIG. 3. The present invention also provides a touch sensor 20, which is made of the transparent conductive film 10 in the above-mentioned embodiment. among them:

The touch sensor 20 includes a touch area 210 and a lead area 220. Specifically, the touch area 210 is located in the middle of the touch sensor 20, and the lead area 220 is arranged around the circumference of the touch area 210. The metal layer 13 is located in the lead area 220.

The touch area 210 includes electrodes 211. Among them, the electrode 211 is an electrode pattern formed by etching the transparent conductive layer 12. Specifically, the electrode pattern is generally elongated and intersects perpendicularly to form a grid. The lead area 220 includes leads 221. The lead 221 is formed by etching the metal layer 13 and the transparent conductive layer 12 located in the lead area 220. The lead 221 has a double-layer structure, thereby achieving electrical connection with the electrode 211.

In addition, the present invention also provides a touch screen (not shown in the figure), and the above touch screen includes the touch sensor 20 in the above embodiment.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and their description is relatively specific and detailed, but they should not be understood as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A transparent conductive film, characterized in that it comprises:

The substrate includes two laminated substrate layers and a flexible adhesive layer located between the two substrate layers, and the two substrate layers are bonded by the flexible adhesive layer;

A transparent conductive layer formed on at least one surface of the substrate;

The metal layer is arranged on the side of the transparent conductive layer away from the substrate.
The transparent conductive film according to claim 1, wherein the thickness of each of the substrate layers is 15 to 30 microns, and the thickness of the flexible adhesive layer is 5 to 15 microns.
The transparent conductive film according to claim 2, wherein the thickness of each base layer is 25 micrometers, and the thickness of the flexible adhesive layer is 10 micrometers.
The transparent conductive film according to claim 1, wherein the base layer is a polycycloolefin layer.
The transparent conductive film according to claim 4, wherein the transparent conductive film further comprises a hard coat layer and an optical adjustment layer laminated between the substrate and the transparent conductive layer and laminated on each other, and The optical adjustment layer is located on the side of the hard coating layer facing the transparent conductive layer.
The transparent conductive film according to any one of claims 1 to 5, wherein the flexible adhesive layer is an optical adhesive layer.
The transparent conductive film according to any one of claims 1 to 5, wherein the in-plane phase difference between the base layer and the flexible adhesive layer is 20 nanometers or less when the wavelength is 590 nanometers.
The transparent conductive film according to any one of claims 1 to 5, wherein the transparent conductive layer is a conductive layer of silver nanowires.
The transparent conductive film according to claim 1, wherein the transparent conductive layer and the metal layer are formed on both surfaces of the substrate.
A touch sensor, characterized in that it is made of the transparent conductive film of any one of claims 1-9, the touch sensor includes a touch area and a lead area, and the metal layer is located in the The lead area, the touch area includes an electrode etched from the transparent conductive layer, and the lead area includes a lead etched from the metal layer and the transparent conductive layer located in the lead area.
A touch screen, wherein the touch screen comprises the touch sensor according to claim 10.