CN113076022A

CN113076022A - Touch screen and preparation method thereof

Info

Publication number: CN113076022A
Application number: CN202010012580.1A
Authority: CN
Inventors: 范杰; 谢邦星; 许建勇
Original assignee: Nanchang OFilm Display Technology Co Ltd
Current assignee: Jiangxi Zhuoxin Microelectronics Co ltd
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2021-07-06

Abstract

The application provides a touch screen and a preparation method of the touch screen, wherein the preparation method of the touch screen comprises the following steps: providing a substrate, wherein the substrate comprises a visible area and a non-visible area; forming conductive metal layers on two surfaces of the substrate which are arranged oppositely; performing a first yellow light process on the conductive metal layer to expose a visible area of the substrate and form a touch lead in a non-visible area of the substrate; coating a nano silver layer on the surface of the conductive metal layer, which is far away from the substrate, wherein the nano silver layer covers the touch lead and the visible area of the substrate; and performing a second yellow light process on the nano silver layer to form a touch electrode in the visible area of the substrate, wherein the touch electrode is connected with the touch lead. The preparation method of the touch screen solves the problems that in the prior art, materials are brittle after an aging process due to the fact that the touch screen adopts an ITO material, and the shrinkage rate of the materials can obviously change along with the aging process, so that the process size is not easy to control, and the development requirement of the touch screen is difficult to meet.

Description

Touch screen and preparation method thereof

Technical Field

The invention relates to the technical field of touch screens, in particular to a touch screen and a preparation method of the touch screen.

Background

As an input device capable of significantly improving human-machine operation, a touch screen is widely applied to a plurality of electronic products, such as a mobile phone, a television, a tablet computer, and the like. Currently, in the touch field, ITO (indium tin oxide) is the most important transparent conductive thin film material at present due to its good light transmittance, conductivity, low thickness and mature manufacturing process. However, as the touch screen gradually develops towards the curved screen and the flexible screen, the material of the ITO material is brittle after aging, and the shrinkage rate of the material obviously changes along with the aging process, so that the process size is not easy to control, and the development requirement of the flexible screen is difficult to meet.

Disclosure of Invention

In view of this, the present application provides a touch screen and a method for manufacturing the same, so as to solve the problems in the prior art that the touch screen is brittle after an aging process due to the ITO material, and the shrinkage rate of the material is significantly changed along with the aging process, so that the process size is not easily controlled, and the development requirement of the touch screen is difficult to meet.

In a first aspect, an embodiment of the present application provides a method for manufacturing a touch screen, where the method for manufacturing a touch screen includes:

providing a substrate, wherein the substrate comprises a visible area and a non-visible area;

forming conductive metal layers on two surfaces of the substrate which are arranged oppositely;

performing a first yellow light process on the conductive metal layer to expose a visible area of the substrate and form a touch lead in a non-visible area of the substrate;

coating a nano silver layer on the surface of the conductive metal layer, which is far away from the substrate, wherein the nano silver layer covers the touch lead and a visible area of the substrate;

and performing a second yellow light process on the nano silver layer to form a touch electrode in the visible area of the substrate, wherein the touch electrode is connected with the touch lead.

Therefore, the nano silver is used as the material for preparing the touch electrode, the aging process of using ITO (indium tin oxide) as the material for preparing the touch electrode is avoided, and the high-temperature aging process is not needed, so that the production efficiency and the finished product quality of the touch screen are not influenced by material expansion and shrinkage, the size of the touch screen is not easy to shrink, and the touch screen has good stability, and the process size is easier to control. Meanwhile, the nano-silver has good ductility and bending resistance, so that the whole touch screen prepared by the method can be bent or folded, and the method can be widely applied to the field of flexible touch screens.

In an embodiment, the performing a first yellow light process on the conductive metal layer to expose a visible region of the substrate and form a touch lead in a non-visible region of the substrate includes:

forming a first light resistance layer on the surface of the conductive metal layer deviating from the substrate;

and sequentially carrying out first exposure, first development and first etching on the first photoresist layer, exposing the visible area of the substrate, and stripping the first photoresist layer of the non-visible area of the substrate to form a touch lead.

Therefore, compared with a common etching method, the touch lead formed by etching through the yellow light process improves the etching precision, so that the prepared touch lead has good performance, and the yield of products is improved.

In one embodiment, after "coating a nano silver layer on a surface of the conductive metal layer facing away from the substrate", the method for manufacturing the touch screen includes:

and coating the surface of the nano silver layer, which is far away from the conductive metal layer, to form an OC layer.

Therefore, the OC layer formed by coating can not only increase the adhesion of the nano-silver layer, but also play a role in protection and insulation.

In one embodiment, the step of performing a second yellow light process on the nano silver layer to form a touch electrode in the visible region of the substrate includes:

forming a second light resistance layer on the surface of the nano silver layer departing from the touch lead;

and sequentially carrying out second exposure, second development and second etching on the second photoresist layer, and stripping the second photoresist layer of the visible area of the substrate to form the touch electrode.

Therefore, compared with a common etching method, the touch electrode formed by etching through the yellow light process improves the etching precision, so that the prepared touch electrode has good performance, and the yield of products is improved.

In one embodiment, the "providing a substrate" comprises:

providing a base layer,

and forming hard coating layers on two surfaces of the substrate layer which are arranged oppositely.

Thus, the base layer cooperates with the hard coat layer to form the base. The hard coat layer is a film layer provided on both sides of the base layer for the purpose of damage resistance, and serves to protect the surface of the base layer. And because the conductive metal layer is arranged on the surface of the hard coating layer far away from the substrate layer, the substrate layer can be protected to avoid being damaged in the subsequent etching process of the conductive metal layer.

In one embodiment, after the "performing the second yellow light process on the nano silver layer to form the touch electrode in the visible area of the substrate", the method for manufacturing the touch screen includes:

and forming an insulating layer on one side of the touch lead and the touch electrode, which is deviated from the substrate, so as to manufacture the touch screen.

Therefore, the insulating layer can cover the surfaces of the touch lead and the touch electrode to form a protective layer. The insulating layer is thin, transparent, wear-resistant and scratch-resistant, can avoid contact between the touch lead and the touch electrode and air, has an obvious protection effect on the touch lead and the touch electrode, and can improve the chemical stability, the ageing resistance and the service life of the touch lead and the touch electrode.

In one embodiment, the "forming an insulating layer on the touch lead and the side of the touch electrode facing away from the substrate" includes:

forming a third light resistance layer on the touch lead and one side of the touch electrode, which is far away from the substrate;

and sequentially carrying out third exposure, third development and curing on the third photoresist layer to form an insulating layer which is pressed on the touch electrode and the touch lead.

Therefore, compared with a common etching method, the insulating layer formed by the yellow light process has good performance, and the yield of products is improved.

In one embodiment, after the step of forming an insulating layer on the side of the touch lead and the touch electrode facing away from the substrate to form the touch screen, the method for manufacturing the touch screen includes:

and covering protective films on two surfaces of the touch screen, which are arranged oppositely, and carrying out outline dimension die cutting and processing on the protective films so as to adapt to the dimension of the touch screen.

Therefore, the touch screen can be protected, scratch, dirt, deformation and the like caused in the transfer process of the touch screen are prevented, and the quality of a finished product of the touch screen is ensured.

In one embodiment, the third photoresist layer is prepared by a coating method, a spin-coating method or a spraying method.

Therefore, the process method can be selected independently according to actual conditions, and the method is high in degree of freedom and high in flexibility.

In a second aspect, an embodiment of the present application further provides a touch screen, where the touch screen is prepared by the method described above.

According to the preparation method of the touch screen, the nano silver is used as the material for preparing the touch electrode, the aging process of using ITO (indium tin oxide) as the material for preparing the touch electrode is avoided, and the high-temperature aging process is not needed, so that the production efficiency and the finished product quality of the touch screen are not influenced by material expansion and shrinkage, the size of the touch screen is not easy to shrink, and the touch screen has good stability, and the process size is easier to control. Meanwhile, the nano-silver has good ductility and bending resistance, so that the whole touch screen prepared by the method can be bent or folded, and the method can be widely applied to the field of flexible touch screens.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic flowchart of a method for manufacturing a touch screen according to an embodiment of the present disclosure;

fig. 2 is a schematic process flow diagram of a manufacturing method of the touch screen shown in fig. 1;

FIG. 3 is a schematic structural view of the substrate shown in FIG. 2;

FIG. 4 is a schematic structural diagram of the conductive metal layer shown in FIG. 2;

FIG. 5 is a schematic structural diagram of the touch lead shown in FIG. 2;

fig. 6 is a schematic structural view of the nano silver layer shown in fig. 2;

FIG. 7 is a schematic structural diagram of the touch electrode shown in FIG. 2;

FIG. 8 is a schematic flowchart of step S100 shown in FIG. 1;

FIG. 9 is a schematic flowchart of step S300 shown in FIG. 1;

FIG. 10 is a flowchart illustrating step S500 shown in FIG. 1;

fig. 11 is a schematic flowchart of another method for manufacturing a touch panel according to an embodiment of the present disclosure;

fig. 12 is a schematic process flow diagram of a manufacturing method of the touch panel shown in fig. 11;

fig. 13 is a schematic structural diagram of a touch screen according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

With the development of electronic devices such as mobile phones and tablet computers, the design of modules such as Liquid Crystal Displays (LCDs) and Touch Panels (TPs) is gradually changed in directions of changing shapes, so that the application materials of the touch panels must be flexible and maintain high transmittance. Touch screens on the current market mainly use an ITO (indium tin oxide) material, and in the preparation process of the touch screen, the ITO material needs to be subjected to an aging process, and the aged ITO material has poor toughness and is not easy to bend, so that the touch screen is difficult to apply to the field of flexible touch screens.

In view of this, the present application provides a method for manufacturing a touch panel. The method is realized by firstly providing a substrate, wherein the substrate comprises a visible area and a non-visible area; secondly, forming conductive metal layers on two surfaces of the substrate which are arranged oppositely; then, performing a first yellow light process on the conductive metal layer to expose the visible area of the substrate and form a touch lead in the non-visible area of the substrate; then, coating a nano silver layer on the surface of the conductive metal layer, which is far away from the substrate, wherein the nano silver layer covers the touch lead and a visible area of the substrate; and finally, performing a second yellow light process on the nano silver layer to form a touch electrode in the visible area of the substrate, wherein the touch electrode is connected with the touch lead.

Referring to fig. 1 and fig. 2 together, fig. 1 is a schematic flow chart of a method for manufacturing a touch screen according to an embodiment of the present disclosure, and fig. 2 is a schematic process flow chart of the method for manufacturing the touch screen shown in fig. 1. As shown in fig. 1, the method for manufacturing a touch screen at least includes the following steps.

S100: a substrate 10 is provided, the substrate 10 includes a visible region 11 and a non-visible region 12.

Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of the substrate shown in fig. 2. The substrate 10 is made of one or more transparent flexible materials, and has good light transmittance on one hand to ensure the normal display function of the touch screen, and on the other hand, has strong flexibility and elasticity, and can support bending at different angles to meet the requirements of the flexible screen and the curved screen. For example, flexible materials include, but are not limited to, PET (Polyethylene terephthalate), PDMS (Polydimethylsiloxane), COP (Cyclic Olefin Polymer), PC (Polycarbonate), and PMMA (polymethyl methacrylate).

The substrate 10 includes a Viewing Area (VA) 11 and a non-viewing area 12 located outside the viewing area 11. Wherein the viewing area 11 is the effective visible area of the human eye, which in the embodiment of the present application is located in the area indicated between the middle two dashed lines shown in fig. 3. It can be understood that the information displayed on the touch screen and the area where the touch control and other operations can be performed on the electronic components such as the protective cover plate and the like disposed on the touch screen are both limited to the visible area 11. The visible area 11 is extended to be the non-visible area 12, in other words, the non-visible area 12 can be regarded as a frame area of the visible area 11. In one embodiment, the non-visible area 12 is disposed around the visible area 11, i.e., the non-visible area 12 is disposed around the visible area 11. In another embodiment, the non-visible region 12 is located on at least one side of the visible region 11, for example, the non-visible region 12 can be disposed on two opposite sides of the visible region 11, and the arrangement is flexible. In the embodiment of the present application, the non-visible region 12 is disposed around the visible region 11 for illustration.

S200: forming conductive metal layers 20 on both surfaces of the substrate 10 disposed opposite to each other;

specifically, referring to fig. 4, fig. 4 is a schematic structural diagram of the conductive metal layer shown in fig. 2. The conductive metal layer 20 is a single layer, and two single-layer conductive metal layers 20 are respectively formed on two opposite surfaces of the substrate 10. That is, the two conductive metal layers 20 share one substrate 10, and the substrate 10 is a flexible substrate capable of providing a double-sided single-layer circuit structure. The structure can reduce the thickness of the touch screen, and the process of attaching two substrates by an OCA (optically Clear adhesive) glue layer is not needed in the preparation process, so that the process is simple, the manufacturing efficiency is high, and the lightweight of the touch screen is facilitated. Compared with a single-sided double-layer structure, the double-sided single-layer structure in the embodiment of the application has the excellent performances of strong stability, high transmittance, strong detection precision and the like.

Further, the conductive metal layer 20 may be disposed on both surfaces of the substrate 10 disposed opposite to each other by using a sputtering method, an evaporation method, or a Chemical Vapor Deposition (CVD) method. The material of the conductive metal layer 20 may be copper, silver, zinc, gold, nickel, or any other metal material with good conductivity, so that the cost of the conductive metal layer 20 can be reduced. That is, the method for forming the conductive metal layer 20 and the material used for the conductive metal layer 20 may be selected according to practical situations, and are not particularly limited. However, in the embodiment of the present application, the material of the conductive metal layer 20 is exemplified by copper, and in order to form the conductive metal layer 20 with better density and uniformity, a copper layer, that is, the conductive metal layer 20, is obtained by sputtering copper material on two surfaces of the substrate 10 opposite to each other by a copper plating process, so as to provide a basis for performing the subsequent process flow.

S300: the first yellow light process is performed on the conductive metal layer 20 to expose the visible region 11 of the substrate 10 and form a touch lead 21 in the non-visible region 12 of the substrate 10.

It is understood that the photolithography technique is used for the yellow light, and the Photoresist (PR) is used as the material. The photoresist is a photosensitive material, which has the unique characteristic of being chemically changed under the action of UV light to be easily dissolved in acid or alkali. The photolithography technique transfers the pattern on the Mask to the photoresist, and then uses a solvent to soak and dissolve or retain the portion of the photoresist exposed to light, so as to form the photoresist pattern which is completely the same as or complementary to the Mask. Since the ambient light source of the photolithography process is yellow light, the process is called a yellow light process. In other words, the yellow light process is a process of exposing and developing a photoresist coated on the surface of a base material to leave a part for protecting a bottom layer, then etching and stripping the film and finally obtaining a permanent pattern.

Referring to fig. 5, fig. 5 is a schematic structural diagram of the touch lead shown in fig. 2. In the embodiment of the application, a first yellow light process is performed on the conductive metal layer 20, that is, after the conductive metal layer 20 is sequentially subjected to press coating of a photoresist film, exposure, development, etching and film stripping, a portion of the conductive metal layer 20 located on the visible region 11 of the substrate 10 is etched away, and a touch lead 21 is formed by etching a portion of the conductive metal layer 20 located on the non-visible region 12 of the substrate 10, where the touch lead 21 is used for connecting with a touch IC (Integrated Circuit) so as to implement a subsequent touch function. Specifically, a gap is formed between two adjacent touch leads 21 and the two adjacent touch leads are insulated from each other. In an embodiment of the application, the touch lead is a copper wire.

It is understood that the first yellow light process described in the embodiment of the present application is to perform the first yellow light process on both the conductive metal layers 20 disposed on the two opposite surfaces of the substrate 10, so as to form the touch leads 21 on the two opposite surfaces of the substrate 10, where the touch leads 21 are formed at positions corresponding to the non-visible areas 12.

S400: and coating a nano silver layer 30 on the surface of the conductive metal layer 20, which faces away from the substrate 10, wherein the nano silver layer 30 covers the touch lead 21 and the visible area 11 of the substrate 10.

Specifically, the nano silver (nanometer silver) has excellent conductivity and small impedance, and has excellent light transmittance and bending resistance due to the nano-scale size effect, so that the flexible transparent conductive film made of the nano silver material, namely the nano silver layer 30, can realize the large-size flexible bending function, is beneficial to the development of large-screen touch products, and has no risk of material fracture.

Further, the nano silver may be nano silver particles or nano silver wires. In the examples of the present application, a silver nanowire is taken as an example for explanation. The nano silver wire (AgNWs) has the characteristics of high transmittance, good conductivity and mechanical property and the like, and becomes an ideal material for preparing the flexible transparent conductive film. The transparent conductive film prepared by using the nano silver wire has the advantages of low cost, easiness in preparation, high transmittance, low square resistance, good bending property and the like.

Further, an oc (over coating) layer (not shown) may be coated on the surface of the nano-silver layer 30 facing away from the conductive metal layer 20. The OC layer can increase the adhesion of the nano silver layer 30 and can also have the effect of protection and insulation.

Referring to fig. 5 and fig. 6 together, fig. 5 is a schematic structural view of the touch lead shown in fig. 2, and fig. 6 is a schematic structural view of the nano silver layer shown in fig. 2. The nano-silver layer 30 is formed by coating on the surface of the conductive metal layer 20 away from the substrate 10, so that the nano-silver layer 30 can cover not only the touch leads 21, but also the visible area 11 of the substrate 10 exposed by the conductive metal layer 20 in step S300. In other words, the nano-silver layer 30 can be regarded as a film layer formed on the visible area 11 of the substrate 10 exposed by the conductive metal layer 20 in the step S300 and covering the touch lead 21. In addition, the nano silver layer 30 may be disposed by a spraying method, a slit coating method, a doctor blade coating method, or a gravure coating method, that is, a suitable process method may be selected according to actual situations, which is not particularly limited in the present application.

It is understood that the coating to form the nano-silver layer 30 in the embodiment of the present application is to coat the two conductive metal layers 20 disposed on the two opposite surfaces of the substrate 10, so as to form the nano-silver layer 30 on the side of each conductive metal layer 20 facing away from the substrate 10.

In the embodiment of the application, the conductive metal layer 20 is formed first, and then the nano silver layer 30 is formed, so that the problem that the nano silver layer 30 formed first is damaged in the process of forming the conductive metal layer 20 later, and the performance of the nano silver layer 30 is influenced, so that the performance of the touch screen is influenced is avoided. The sequence of the process flow ensures the yield of the touch screen, so that the prepared touch screen has good performance. In addition, the nano silver layer 30 is arranged on the touch lead 21, so that the touch lead 21 can be well protected, the touch lead 21 is further relieved or prevented from being oxidized, and the touch screen is guaranteed to have better reliability.

Further, the arrangement of the nano silver layer 30 avoids an aging process required for preparing an electrode material by using ITO (indium tin oxide) in a subsequent process, and on one hand, avoids the problem that the production efficiency and the finished product quality of the touch screen are affected due to material expansion and shrinkage. On the other hand, the nano silver is a low-impedance thin film material, is beneficial to improving the response speed of the touch screen, has bending resistance, and has great advantages compared with the touch screen made of the traditional ITO material when the touch screen is made into a large-size touch screen.

S500: and performing a second yellow light process on the nano silver layer 30 to form a touch electrode 31 in the visible area 11 of the substrate 10, wherein the touch electrode 31 is connected with the touch lead 21.

Referring to fig. 7, fig. 7 is a schematic structural diagram of the touch electrode shown in fig. 2. Specifically, the second yellow light process is performed on the nano silver layer 30, that is, after the nano silver layer 30 is sequentially subjected to photoresist film pressing, exposure, development, etching and film stripping, only the portion of the nano silver layer 30 located in the visible area 11 of the substrate 10, that is, the portion of the visible area 11 of the substrate 10 exposed by the conductive metal layer 20 in step S300 is left, and the touch electrode 31 is formed at the portion, and the touch electrode 31 may be connected to a touch IC (Integrated Circuit) through connection of the touch lead 21, so as to implement the touch function of the touch screen. Specifically, a gap is formed between two adjacent touch electrodes 31 and the two adjacent touch electrodes 31 are insulated from each other, and each touch electrode 31 is electrically connected to one touch lead 21. In other words, the touch electrode 31 and the touch lead 21 are connected to form a loop to constitute the touch layer 50 of the touch screen.

It is understood that the second photolithography process described in this embodiment of the application is to perform the second photolithography process on both the nano silver layers 30 disposed on the surfaces of the two conductive metal layers 20 facing away from the substrate 10, so as to form the touch electrodes 31 on both the surfaces of the substrate 10 opposite to each other corresponding to the visible areas 11.

According to the preparation method of the touch screen, the nano silver is used as the material for preparing the touch electrode 31, the aging process of using ITO (indium tin oxide) as the material for preparing the touch electrode 31 is avoided, and the high-temperature aging process is not needed, so that the production efficiency and the finished product quality of the touch screen are not influenced by material expansion and shrinkage, the size of the touch screen is not easy to shrink, and the touch screen has good stability, and the process size is easier to control. Meanwhile, the nano-silver has good ductility and bending resistance, so that the whole touch screen prepared by the method can be bent or folded, and the method can be widely applied to the field of flexible touch screens.

Referring to fig. 3 and 8 together, fig. 3 is a schematic structural diagram of the substrate shown in fig. 2, and fig. 8 is a schematic flow chart of step S100 shown in fig. 1.

The step of providing the substrate 10 comprises:

s110: a base layer 13 is provided.

Specifically, the base layer 13 is a transparent base film made of flexible materials including, but not limited to, PET, PDMS, COP, PC, and PMMA. In the examples of the present application, the flexible material is described by taking COP as an example, considering that COP has a light transmittance of about 92% and also has excellent mechanical properties, temperature resistance and weather resistance.

S210: hard coat layers 14 are formed on both surfaces of the base layer 13 disposed opposite to each other.

Specifically, the base layer 13 cooperates with the hard coating layer 14 to form the substrate 10. The Hard coating film (HC film) 14 is a film layer provided on both sides of the base layer 13 for the purpose of damage resistance, and functions to protect the surface of the base layer 13. It is understood that the conductive metal layer 20 is disposed on the surface of the hard coating layer 14 away from the substrate layer 13, and the substrate layer 13 can be protected to prevent the conductive metal layer 20 from being damaged during the subsequent etching process. As the composition of the HC layer, for example: the curable composition may be a curable composition containing an ionizing radiation-curable compound and a cured product thereof, a thermoplastic resin, a thermosetting resin solution, a cured product of a curable composition containing a thermosetting resin, or the like, and a curable composition containing an ionizing radiation-curable compound is preferred.

Referring to fig. 5 and 9 together, fig. 5 is a schematic structural diagram of the touch lead shown in fig. 2, and fig. 9 is a schematic flow chart of step S300 shown in fig. 1.

The first yellow light process is performed on the conductive metal layer 20 to expose the visible area 11 of the substrate 10 and form the touch lead 21 in the non-visible area 12 of the substrate 10, and the steps include:

s310: a first photoresist layer (not shown) is formed on the surface of the conductive metal layer 20 away from the substrate 10.

In the embodiment of the present application, a photoresist coating is performed on the conductive metal layer 20 to form a first photoresist layer. The first photoresist layer may be prepared by a coating method, a spin-coating method or a spraying method, and an appropriate process method may be selected according to actual conditions, which is not particularly limited. In the embodiment of the present application, the photoresist dropped on the conductive metal layer 20 is spun off by a spin coating method using a photoresist coating apparatus using a centrifugal force generated by spin, and a first photoresist film is formed under the combined action of a surface tension of the photoresist and the centrifugal force of spin. Wherein, the photoresist is a photosensitive material mainly formed by mixing resin, photosensitizer and solvent. After the first photoresist film is formed, it is baked at a certain temperature to form a dried first photoresist film, i.e., a first photoresist layer.

S320: the first photoresist layer is sequentially subjected to first exposure, first development and first etching to expose the visible area 11 of the substrate 10, and the first photoresist layer of the non-visible area 12 of the substrate 10 is stripped to form the touch lead 21.

Specifically, under the action of a first photomask (not shown), light emitted by a light source is irradiated onto the surface of the first photoresist layer through the first photomask to expose the first photoresist layer for the first time, wherein for a transparent portion on the first photomask, the light is irradiated onto the first photoresist layer through the transparent portion and reacts with a corresponding portion of the first photoresist layer, and for an opaque portion on the first photomask, the light cannot be transmitted but the corresponding portion of the first photoresist layer does not react, so that a pattern on the first photomask is projected onto the first photoresist layer under the irradiation of the light. In the embodiment of the present application, when the conductive metal layer 20 is exposed, a first mask having a touch lead 21 pattern may be selected to expose to form the touch lead 21 located in the non-visible area 12 of the substrate 10, and the light source is exemplified by an UV (ultraviolet) light source.

And spraying a photoresist developing solution on the first photoresist layer after the first exposure treatment, wherein the photoresist developing solution dissolves the irradiated part of the first photoresist layer, while the part which is not irradiated with light is not dissolved and remains, and the remaining part forms a patterned first photoresist layer.

It is understood that, in the embodiments of the present application, the material of the first photoresist layer is a positive photoresist, and the exposed portion is soluble in the photoresist developer, while the unexposed portion is not soluble in the photoresist developer. Of course, in other embodiments, a negative photoresist may be applied, the exposed portions of which cure and are not dissolved in the photoresist developer, and the unexposed portions of which are dissolved in the photoresist developer.

Then, the conductive metal layer 20 is etched for the first time, the portion of the conductive metal layer 20 located in the visible region 11 of the substrate 10 is etched away, and the touch lead 21 is formed by etching the portion of the conductive metal layer 20 located in the non-visible region 12 of the substrate 10. Specifically, the conductive metal layer 20 is etched by wet etching using an etching solution, and since the etching solution reacts with the conductive metal layer 20 but does not react with the first photoresist layer, the metal layer not covered by the patterned first photoresist layer is removed after reacting with the etching solution, and the conductive metal layer 20 covered by the patterned first photoresist layer is retained to form the patterned conductive metal layer 20 having the same pattern as the patterned first photoresist layer. And dripping the photoresist removing liquid on the patterned first photoresist layer to enable the photoresist removing liquid to react with the patterned first photoresist layer to strip the patterned first photoresist layer so as to form the touch lead 21.

Referring to fig. 7 and 10 together, fig. 7 is a schematic structural diagram of the touch electrode shown in fig. 2, and fig. 10 is a schematic flow chart of step S500 shown in fig. 1.

The second yellow light process is performed on the nano silver layer 30, and the step of forming the touch electrode 31 located in the visible area 11 of the substrate 10 includes:

s510: a second photoresist layer (not shown) is formed on the surface of the nano-silver layer 30 away from the touch lead 21.

In the embodiment of the present application, a photoresist coating is performed on the nano-silver layer 30 to form a second photoresist layer. The second photoresist layer may be prepared by a coating method, a spin-coating method or a spraying method, and an appropriate process method may be selected according to actual conditions, which is not particularly limited. In the embodiment of the present application, the photoresist dropped on the conductive metal layer 20 is spun off by a spin coating method using a photoresist coating apparatus using a centrifugal force generated by spin, and a second photoresist film is formed under the combined action of the surface tension of the photoresist and the centrifugal force of spin. Wherein, the photoresist is a photosensitive material mainly formed by mixing resin, photosensitizer and solvent. After the second photoresist film is formed, it is baked at a certain temperature to form a dried second photoresist film, i.e., a second photoresist layer.

S520: after the second photoresist layer is sequentially subjected to the second exposure, the second development and the second etching, the second photoresist layer in the visible area 11 of the substrate 10 is stripped to form the touch electrode 31.

Specifically, under the action of a second photomask (not shown), the light emitted by the light source is irradiated onto the surface of the second photoresist layer through the second photomask to expose the second photoresist layer for the second time, wherein for the transparent portion of the second photomask, the light is irradiated onto the second photoresist layer through the transparent portion and reacts with the corresponding portion of the second photoresist layer, and for the opaque portion of the second photomask, the light cannot penetrate through the corresponding portion of the second photoresist layer but does not react, so that the pattern on the second photomask is projected onto the second photoresist layer under the irradiation of the light. In the embodiment of the present application, when the nano silver layer 30 is exposed, a mask having a pattern of the touch electrode 31 may be selected to expose to form the touch electrode 31 located in the visible area 11 of the substrate 10. The light source is exemplified by an Ultraviolet (UV) light source.

And spraying a photoresist developing solution on the second photoresist layer after the second exposure treatment, wherein the photoresist developing solution dissolves the irradiated part of the second photoresist layer, while the part which is not irradiated with light is not dissolved and remains, and the remaining part forms a patterned second photoresist layer.

It is understood that, in the embodiments of the present application, the material of the second photoresist layer is a positive photoresist, and the exposed portion is soluble in the photoresist developer, while the unexposed portion is not soluble in the photoresist developer. Of course, in other embodiments, a negative photoresist may be applied, the exposed portions of which cure and are not dissolved in the photoresist developer, and the unexposed portions of which are dissolved in the photoresist developer.

Then, the nano silver layer 30 is etched for the second time, the portion of the nano silver layer 30 located in the non-visible area 12 of the substrate 10 and the portion located on the touch lead 21 are etched away, only the portion of the nano silver layer 30 located in the visible area 11 of the substrate 10 is left, and the touch electrode 31 is formed at this portion, the touch electrode 31 located in the visible area 11 of the substrate 10 is connected with the touch lead 21 located in the non-visible area 12 of the substrate 10 to form the touch layer 50 of the touch screen, so that the touch signal sensed by the touch electrode 31 can be transmitted to the external detection circuit, i.e., the touch IC described above, through the touch lead 21, thereby implementing the touch function of the touch screen.

Specifically, the nano-silver layer 30 is etched for the second time by using the etching solution through wet etching, and since the etching solution reacts with the nano-silver layer 30 but does not react with the second photoresist layer, the metal layer not covered by the patterned second photoresist layer is removed after reacting with the etching solution, and the patterned nano-silver layer 30 covered by the patterned second photoresist layer is retained to form the patterned nano-silver layer 30 having the same pattern as the patterned second photoresist layer. And dropping a photoresist removing solution on the patterned second photoresist layer, so that the photoresist removing solution reacts with the patterned second photoresist layer to strip the patterned second photoresist layer, thereby forming the touch electrode 31.

Referring to fig. 11 and 12 together, fig. 11 is a schematic flow chart of another touch panel manufacturing method according to an embodiment of the present application, and fig. 12 is a schematic process flow chart of the touch panel manufacturing method shown in fig. 11, which is substantially the same as that of the foregoing embodiment, and different from the foregoing embodiment, the present embodiment further includes the following steps S600 to S700.

S600: an insulating layer 40 is formed on the touch lead 21 and the side of the touch electrode 31 away from the substrate 10, so as to obtain the touch screen.

The insulating layer 40 is a film formed by the third photolithography process, and the following process for preparing the insulating layer 40 is described in detail.

First, a third photoresist layer is formed on the side of the touch lead 21 and the touch electrode 31 away from the substrate 10. In other words, a photoresist coating is performed on the touch layer 50 formed by the touch lead 21 and the touch electrode 31 to form a third photoresist layer. The third photoresist layer may be prepared by a coating method, a spin-coating method or a spraying method, and a suitable process method may be selected according to the actual situation, which is not particularly limited. In the embodiment of the present application, the photoresist dropped on the conductive metal layer 20 is spun off by a spin coating method using a photoresist coating apparatus using a centrifugal force generated by spin, and a third photoresist film is formed under the combined action of the surface tension of the photoresist and the centrifugal force of spin. Wherein, the photoresist is a photosensitive material mainly formed by mixing resin, photosensitizer and solvent. After the third photoresist film is formed, it is baked at a certain temperature to form a dried third photoresist film, i.e., a third photoresist layer.

Then, the third photoresist layer is sequentially exposed, developed and cured for the third time to form the insulating layer 40 overlying the touch electrode 31 and the touch lead 21.

Specifically, under the action of the third photomask, the light source is used to emit light to irradiate the surface of the third photoresist layer through the third photomask to expose the third photoresist layer for the third time, wherein for the transparent part on the third photomask, the light irradiates the third photoresist layer through the transparent part and reacts with the corresponding part of the third photoresist layer, and for the non-transparent part on the third photomask, the light cannot penetrate but the corresponding part of the third photoresist layer does not react, so that the pattern on the photomask is projected on the third photoresist layer under the irradiation of the light. The light source is selected according to the material of the third photoresist layer, and different third photoresist layers correspond to light sources with different wavelengths. In the examples of the present application, the light source is exemplified by an Ultra-Violet Ray (UV) light source.

And spraying photoresist developing solution on the third photoresist layer after the third exposure treatment, wherein the photoresist developing solution dissolves the part of the third photoresist layer irradiated by light, the part not irradiated by light is not dissolved and remains, and the remaining part forms the patterned third photoresist layer.

Then, the third photoresist layer is cured to form the insulating layer 40 on the side of the touch layer 50 away from the substrate 10. It should be noted that, in the embodiment of the present application, the forming of the insulating layer 40 is to perform the pressing of the insulating layer 40 on the two touch control layers 50 disposed on the two opposite surfaces of the substrate 10, so as to form the insulating layer 40 on the surface of each touch control layer 50 away from the substrate 10.

An insulating layer 40 is coated on the surface of the touch layer 50, so that the insulating layer 40 covers the surface of the touch layer 50 to form a protective layer. Specifically, the insulating layer 40 is thin, transparent, wear-resistant and scratch-resistant, so that the touch layer 50 can be prevented from contacting with air, the touch layer 50 is obviously protected, and the chemical stability, the aging resistance and the service life of the touch layer can be improved.

S700: and covering protective films (not shown) on two surfaces of the touch screen, which are arranged oppositely, and performing outline dimension die cutting and forming on the protective films so as to adapt to the dimension of the touch screen.

Specifically, the protective film is an essential object for protecting the touch screen, and the protective film has a main function of protecting the touch screen and preventing the touch screen from being scratched, stained, deformed and the like in a transfer process. Therefore, the operation of the protective film attaching process is also an important link for ensuring the quality of the finished touch screen product, after the touch screen is manufactured, the touch screen needs to be coated, and the protective film is subjected to contour dimension die cutting and forming according to the drawing requirements so as to attach the touch screen, so that the protection of the touch screen is enhanced, the quality of the finished touch screen product is ensured, and good preparation is provided for subsequent packaging and warehousing.

The touch screen provided by the present application will be described in detail below with reference to the above-mentioned method for manufacturing a touch screen.

Referring to fig. 13, fig. 13 is a schematic structural diagram of a touch screen according to an embodiment of the present disclosure.

In an embodiment of the present application, a touch screen includes:

a substrate 10, the substrate 10 including a visible region 11 and a non-visible region 12:

the touch layer 50 is disposed on two opposite surfaces of the substrate 10, the touch layer 50 includes a touch electrode 31 located in the visible region 11 of the substrate 10 and a touch lead 21 located in the non-visible region 12 of the substrate 10, wherein the touch electrode 31 is connected to the touch lead 21;

and the insulating layer 40 is arranged on the surface of the touch layer 50, which faces away from the substrate 10.

In the embodiment of the present application, the substrate 10 includes a substrate layer 13 and a hard coating layer disposed on two opposite surfaces of the substrate layer 13, and the touch layer 50 is disposed on a surface of the hard coating layer facing away from the substrate layer 13. Specifically, the touch lead 21 is formed by the first yellow light process on the conductive metal layer 20 disposed on the two opposite surfaces of the substrate 10 by the aforementioned method for manufacturing a touch screen. The touch electrode 31 is formed by the second yellow light process on the nano silver layer 30 disposed on the surface of the conductive metal layer 20 away from the substrate 10 by the aforementioned method for preparing a touch screen, and the touch lead 21 and the touch electrode 31 form the touch layer 50 of the touch screen, so as to implement the touch function of the touch screen.

According to the preparation method of the touch screen, the nano silver is used as the material for preparing the touch electrode 31, the aging process required by using ITO (indium tin oxide) as the material for preparing the touch electrode 31 is avoided, and the high-temperature aging process is not needed, so that the production efficiency and the finished product quality of the touch screen are not influenced by material expansion and shrinkage, the size of the touch screen is not easy to shrink, the stability is good, the process size is easier to control, and meanwhile, the nano silver has good ductility and bending resistance, so that the whole prepared touch screen can be bent or folded, and the preparation method can be widely applied to the field of flexible touch screens.

The above embodiments of the present invention are described in detail, and the principle and the implementation of the present invention are explained by applying specific embodiments, and the above description of the embodiments is only used to help understanding the method of the present invention and the core idea thereof; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A preparation method of a touch screen is characterized by comprising the following steps:

2. The method of claim 1, wherein performing a first photolithography process on the conductive metal layer to expose a visible region of the substrate and form a touch lead in a non-visible region of the substrate comprises:

3. The method for preparing a touch screen according to claim 1, wherein after the step of coating a nano silver layer on the surface of the conductive metal layer facing away from the substrate, the method for preparing a touch screen comprises the following steps:

4. The method of claim 1, wherein performing a second photolithography process on the nano-silver layer to form a touch electrode in a visible area of the substrate comprises:

5. The method for preparing a touch screen according to claim 1, wherein the providing a substrate comprises:

providing a base layer,

6. The method for preparing a touch screen according to any one of claims 1 to 5, wherein after the step of performing a second yellow light process on the nano silver layer to form a touch electrode in the visible area of the substrate, the method for preparing a touch screen comprises the following steps:

7. The method for manufacturing a touch screen according to claim 6, wherein the step of forming an insulating layer on the touch lead and the side of the touch electrode away from the substrate comprises:

8. The method for manufacturing a touch screen according to claim 6, wherein after the step of forming an insulating layer on the side of the touch lead and the touch electrode facing away from the substrate to manufacture the touch screen, the method for manufacturing the touch screen comprises the steps of:

9. The method for preparing a touch screen according to claim 7, wherein the third photoresist layer is prepared by a coating method, a spin coating method or a spraying method.

10. A touch screen prepared by the method of any one of claims 1-9.