CN110058725B

CN110058725B - Preparation method of touch screen

Info

Publication number: CN110058725B
Application number: CN201910168587.XA
Authority: CN
Inventors: 谢自民; 冯波; 郭向阳; 陈春明; 平财明; 林涛
Original assignee: Suzhou Lanpei Photoelectric Technology Co ltd
Current assignee: Suzhou Lanpei Photoelectric Technology Co ltd
Priority date: 2019-03-06
Filing date: 2019-03-06
Publication date: 2021-11-05
Anticipated expiration: 2039-03-06
Also published as: WO2020177736A1; CN110058725A

Abstract

The invention provides a preparation method of a touch screen, which comprises the following steps: providing a printing working platform provided with a soft gasket; preparing seed ink; scraping the seed ink on the soft liner by using a scraping tool to form a first seed layer in each first groove structure; forming a first metal wire in the first groove structure based on the first seed layer; forming a first transparent optical adhesive layer on the upper surface of the driving layer structure; scraping the seed ink on the soft liner by using a scraping tool to form a second seed layer in each second groove structure; forming a second metal wire in each second groove structure based on the second seed layer; the sensing layer structure is attached to the upper surface of the first transparent optical adhesive layer; forming a second transparent optical adhesive layer on the upper surface of the induction layer structure; and providing a transparent cover layer, and attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer. The invention does not need additional steps of pre-curing and cleaning, thereby simplifying the process flow and reducing the production cost.

Description

Preparation method of touch screen

Technical Field

The invention belongs to the technical field of touch control, and particularly relates to a preparation method of a touch screen.

Background

Touch screens generally have metal grids to form channels and function. The metal grids are mostly in a regular pattern, such as a rectangle, a diamond or a hexagon. The metal mesh in the existing touch screen is generally obtained by forming a conductive layer in a groove structure of a flexible material layer, and the obtained metal mesh is connected with a processing chip through a Flexible Printed Circuit (FPC). In the prior art, as shown in fig. 1, a method for forming a conductive layer generally includes placing a flexible laminated structure 10 including a flexible substrate 101 and a flexible material layer 102 on an upper surface of a printing platform 12, dropping a silver paste 13 on the upper surface of the flexible material layer 102, and then scraping the silver paste 13 with a scraper 14 so that the silver paste 13 is filled in each of the groove structures 11 and then curing the silver paste to obtain the conductive layer.

However, when the above-mentioned process method is used for blade coating of the silver paste 13, since the printing working platform 12 is generally a metal working platform, especially when the area of the metal working platform is relatively large, the flatness of the upper surface of the printing working platform 12 cannot be guaranteed, that is, pits or protrusions exist on the upper surface of the printing working platform 12, and when the silver paste 13 is blade coated, since the pits or protrusions exist on the upper surface of the printing working platform 12, the silver paste 13 remains on the upper surface of the flexible material layer 102 while being filled in the groove structure 11; need after the blade coating is accomplished wash the upper surface of flexible material layer 102 to will remain in flexible material layer 102 upper surface silver thick liquid 13 is got rid of, can after the washing with silver thick liquid 13 carries out the sintering solidification in order to form the conducting layer to make the whole process steps of touch-control screen preparation complicated, the cost is higher.

Meanwhile, the existing silver paste 13 belongs to noble metal paste, which inevitably results in high cost.

Disclosure of Invention

In view of the above disadvantages of the prior art, an object of the present invention is to provide a method for manufacturing a touch panel, which is used to solve the problems that in the prior art, when silver paste is blade-coated on the upper surface of a flexible material layer, a residual silver paste exists on the upper surface of the flexible material layer, so that after blade coating is completed, the upper surface of the flexible material layer needs to be cleaned, and after cleaning, the silver paste can be sintered and cured to form a conductive layer, so that the whole process step is relatively complicated and the production cost is relatively high, and when the conductive layer is manufactured by using the silver paste, the cost is relatively high because the silver paste belongs to a noble metal.

In order to achieve the above and other related objects, the present invention provides a method for manufacturing a touch panel, including:

providing a printing working platform, wherein a soft gasket is arranged on the upper surface of the printing working platform;

arranging a first flexible laminated structure on the upper surface of the soft gasket, wherein the first flexible laminated structure comprises a first flexible substrate and a first flexible material layer, the first flexible substrate is positioned on the upper surface of the soft gasket, the first flexible material layer is positioned on the upper surface of the first flexible substrate, and a plurality of first groove structures are formed on the upper surface of the first flexible material layer;

the preparation method of the seed ink comprises the following steps:

providing iron powder and a first organic solvent, and uniformly mixing the iron powder and part of the first organic solvent under a reducing atmosphere to obtain a first mixture;

providing a high molecular polymer, a second organic solvent and a defoaming agent, and mixing the high molecular polymer, the second organic solvent and the defoaming agent to obtain a second mixture;

providing nano silicon dioxide powder, and uniformly mixing the nano silicon dioxide powder, part of the second mixture and the first mixture to obtain a third mixture;

grinding the third mixture to enable the nano silicon dioxide powder to be in sufficient contact with the iron powder so as to obtain slurry of the iron powder with the surface coated with the silicon dioxide layer;

continuously adding the first organic solvent, the second mixture and the auxiliary agent into the slurry, and uniformly mixing to obtain the seed ink;

placing the seed ink on an upper surface of the first layer of flexible material; using a blade coating tool to blade coat the seed ink so that the seed ink is filled in each first groove structure to form a first seed layer;

forming first metal wires in the first groove structure based on the first seed layer, wherein the first metal wires are connected with each other to form a first metal grid; the first flexible laminated structure, the first seed layer and the first metal grid form a driving layer structure together;

forming a first transparent optical adhesive layer on the upper surface of the driving layer structure;

arranging a second flexible laminated structure on the upper surface of the soft gasket, wherein the second flexible laminated structure comprises a second flexible substrate and a second flexible material layer, the second flexible substrate is positioned on the upper surface of the soft gasket, the second flexible material layer is positioned on the upper surface of the second flexible substrate, and a plurality of second groove structures are formed on the upper surface of the second flexible material layer;

placing the seed ink on the upper surface of the second flexible material layer, and carrying out blade coating on the seed ink by using the blade coating tool so that the seed ink is filled in each second groove structure to form a second seed layer;

forming second metal wires in each second groove structure based on the second seed layer, wherein the second metal wires are connected with each other to form a second metal grid; the second flexible laminated structure, the second seed layer and the second metal grid form an induction layer structure together;

the sensing layer structure is attached to the upper surface of the first transparent optical adhesive layer;

forming a second transparent optical adhesive layer on the upper surface of the sensing layer structure;

and providing a transparent cover layer, and attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer.

Optionally, the printing work platform comprises a metal work table; the soft gasket comprises a gasket with Shore A hardness of 30-80 degrees, and the thickness of the soft gasket is 0.5-10 mm.

Optionally, during the scraping process of the seed ink on the upper surface of the first flexible material layer, an included angle between the scraping tool and the upper surface of the first flexible material layer is 30-70 °, a scraping pressure includes 4-6 kilograms of force per square centimeter, and a scraping speed includes 50-260 millimeters per second; in the process of blade coating the seed ink on the upper surface of the second flexible material layer, an included angle between the blade coating tool and the upper surface of the second flexible material layer is 30-70 degrees, blade coating pressure comprises 4-6 kilograms of force per square centimeter, and blade coating speed comprises 50-260 millimeters per second.

Optionally, the particle size of the iron powder is 0.2 nm to 5 μm, and the particle size of the nano-silica powder is less than 100 nm.

Optionally, in the first mixture, the mass ratio of the first organic solvent to the iron powder is 0.5-10; in the third mixture, the mass ratio of the nano silicon dioxide powder to the iron powder is 0.1-3.

Optionally, providing a high molecular polymer, a second organic solvent, and a defoaming agent, and mixing the high molecular polymer, the second organic solvent, and the defoaming agent to obtain a second mixture includes the following steps:

providing the high molecular polymer and the second organic solvent, adding the high molecular polymer into the second organic solvent, stirring and at least heating until the high molecular polymer is completely dissolved to obtain a mixed solution;

providing the defoaming agent, adding the defoaming agent into the mixed solution, stirring and vacuumizing to remove oxygen dissolved in the mixed solution.

Optionally, the temperature for heating after adding the high molecular polymer into the second organic solvent comprises 40 ℃ to 90 ℃; and after the high molecular polymer is completely dissolved in the second organic solvent, continuously heating for 5-10 hours.

Optionally, in the process of removing the dissolved oxygen in the solution, the environment where the solution is located is pumped to a negative pressure, and the pressure is maintained for 2 to 3 hours.

Optionally, the first organic solvent and the second organic solvent each comprise: ethyl acetate, methyl ethyl ketone, dipropylene glycol methyl ether carbonate, butyl carbitol acetate, diethylene glycol ethyl ether, propylene glycol methyl ether carbonate, ethanol, alpha terpineol, butyl carbitol, propylene glycol methyl ether, dipropylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, a mixture of amyl acetates, n-butyl acetate, isobutyl acetate, n-propyl acetate, isopropyl acetate, n-butyl propionate, ethyl 3-ethoxypropionate, dibutyl phthalate, n-pentyl propionate, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexylene glycol, a mixture of amyl alcohols, n-butanol, isobutanol, isopropanol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, amyl alcohol, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexyl glycol, amyl alcohol, a mixture of amyl alcohol, n-butanol, isobutanol, isopropyl alcohol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, ethyl acetate, butyl alcohol, butyl, N-pentanol, n-propanol or trimethylnonanol; the high molecular polymer comprises: polyurethane, polycarbonate, polyvinyl chloride, polymethyl methacrylate, phenoxy resin, polyester, ethylene copolymer; the defoaming agent comprises: higher alcohol organic compounds, polyether organic compounds or silicon organic compounds; the auxiliary agent comprises: cationic, anionic, nonionic or amphoteric auxiliaries.

Optionally, the third mixture is milled by a three-roll mill, wherein the distance between the rolls during milling comprises 1 micron to 25 microns.

Optionally, the depth of the first groove structure includes 1 micron to 20 microns, and the width of the first groove structure includes 1 micron to 10 microns; the sum of the thicknesses of the first metal line and the first seed layer is less than or equal to the depth of the first groove structure, and the width of the first metal line is the same as that of the first groove structure; the depth of the second groove structure is 1-20 micrometers, and the width of the second groove structure is 1-10 micrometers; the sum of the thicknesses of the second metal line and the second seed layer is less than or equal to the depth of the second groove structure, and the width of the second metal line is the same as that of the second groove structure.

Optionally, the first transparent optical cement includes OCA optical cement, the second transparent optical cement includes OCA optical cement, and the transparent cover layer includes transparent glass.

Optionally, while the first groove structure is formed on the upper surface of the first flexible material layer, a first lead groove is formed on the upper surface of the first flexible material layer, and the first lead groove is communicated with the first groove structure; the first seed layer is formed in the first groove structure and the first lead groove at the same time; forming a first lead in the first lead groove while forming the first metal line in the first groove structure, wherein the first lead is connected with the first metal line;

forming a second groove structure on the upper surface of the second flexible material layer, and forming a second lead groove on the upper surface of the second flexible material layer, wherein the second lead groove is communicated with the second groove structure; the second seed layer is formed in the second groove structure and the second lead groove at the same time; and forming a second lead in the second lead groove while forming the second metal wire in the second groove structure, wherein the second lead is connected with the second metal wire.

Optionally, the step of attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer further includes:

providing a flexible circuit board and a processing chip;

coupling the flexible circuit board with the first metal mesh, the second metal mesh and the processing chip so that the first metal mesh and the second metal mesh are electrically connected with the processing chip through the flexible circuit board.

Optionally, the seed ink comprises the following components in percentage by mass:

10 to 90 percent of iron powder coated with a silicon dioxide layer on the surface;

5 to 50 percent of high molecular polymer;

10 to 50 percent of organic solvent;

0.1 to 10 percent of auxiliary agent;

0.01 to 10 percent of defoaming agent.

As described above, the preparation method of the touch screen of the present invention has the following beneficial effects:

in the preparation method of the touch screen, when the first seed layer and the second seed layer are prepared, the first flexible laminated structure and the second flexible laminated structure are respectively arranged on the upper surface of the printing working platform provided with the soft liner for blade coating of the seed ink, due to the existence of the soft liner, when a blade coating tool is used for blade coating of the seed ink, the soft liner can absorb the local uneven factors of the printing working platform under the action of blade coating pressure, so that the residue of the seed ink on the surfaces of the first flexible material layer and the second flexible material layer is avoided, the cleanliness of the upper surface of the first flexible material layer and the cleanliness of the upper surface of the second flexible material layer are ensured after the blade coating is finished, an additional step of pre-curing the seed ink and a step of cleaning the upper surface of the first flexible material layer and the upper surface of the second flexible material layer are not required, and the process flow is simplified, the production cost is reduced;

the seed ink prepared by the invention adopts iron powder as a raw material, and the iron belongs to base metal, so that the production cost can be reduced;

the surface of the iron powder in the seed ink prepared by the invention is coated with the silicon dioxide layer, namely the surface of the iron powder in the first seed layer and the second seed layer is coated with the silicon dioxide layer, the silicon dioxide layer is adsorbed on the surface of the iron powder through physical adsorption, and has the characteristic of lasting coating, and the silicon dioxide layer has the repulsion action on oxygen and can prevent the contact of the oxygen and the iron powder, so that the zero-valent chemical valence state of the iron powder is ensured, the iron powder keeps high reducibility, the disconnection of a first metal wire and a second metal wire formed based on the first seed layer and the second seed layer can be avoided, the performance of a first metal grid and a second metal grid formed is ensured, and the performance of a touch screen is further ensured;

when the seed ink is prepared, firstly, the iron powder is added into the first organic solvent in a reducing atmosphere and is uniformly stirred and mixed, so that the surface of the iron powder is fully soaked in the first organic solvent, and the iron powder can be prevented from contacting oxygen in the subsequent preparation process, so that the iron powder is prevented from being oxidized;

when the seed ink is prepared, the three-roller grinder is used for grinding the third mixture, so that the grinding speed is high, the yield is high, and the energy consumption is low;

when the seed ink is prepared, the high molecular polymer is dissolved in the second organic solvent and then added into the first mixture together with the nano silicon dioxide powder, and the coating of the first organic solvent on the iron powder cannot be damaged because the high molecular polymer is dissolved in the second organic solvent, so that the iron powder can be prevented from being oxidized;

when the seed ink is prepared, the high molecular polymer is dissolved in the second organic solvent to obtain a mixed solution, then the defoaming agent is added to remove oxygen dissolved in the mixed solution to obtain a second mixture, and then the second mixture and the nano silicon dioxide powder are added to the first mixture together to form a third mixture, so that the third mixture is ensured to have no oxygen, and further, the iron powder is prevented from being oxidized.

Drawings

Fig. 1 is a schematic structural diagram illustrating a silver paste doctor blade coating on an upper surface of a flexible material layer in the prior art.

Fig. 2 is a flowchart illustrating a method for manufacturing a touch panel according to the present invention.

Fig. 3 is a schematic cross-sectional structure diagram of the structure obtained in step 1) in the method for manufacturing a touch panel according to the present invention.

Fig. 4 is a schematic cross-sectional structure diagram of the structure obtained in step 2) in the method for manufacturing a touch panel according to the present invention.

Fig. 5 to 7 are schematic cross-sectional structure diagrams of the structure obtained in step 4) of the method for manufacturing a touch panel according to the present invention.

Fig. 8 is a schematic cross-sectional structure diagram of the structure obtained in step 5) in the method for manufacturing a touch panel according to the present invention.

Fig. 9 is a schematic cross-sectional structure diagram of the structure obtained in step 6) in the method for manufacturing a touch panel according to the present invention.

Fig. 10 is a schematic cross-sectional structure diagram of the structure obtained in step 7) of the method for manufacturing a touch panel according to the present invention.

Fig. 11 to 13 are schematic cross-sectional structure diagrams of the structure obtained in step 8) in the method for manufacturing a touch panel according to the present invention.

Fig. 14 is a schematic cross-sectional structure diagram of the structure obtained in step 9) of the method for manufacturing a touch panel according to the present invention.

Fig. 15 is a schematic cross-sectional structure diagram of the structure obtained in step 10) of the method for manufacturing a touch panel according to the present invention.

Fig. 16 is a schematic cross-sectional structure diagram of the structure obtained in step 11) in the method for manufacturing a touch panel according to the present invention.

Fig. 17 is a schematic cross-sectional structure diagram of the structure obtained in step 12) in the method for manufacturing a touch panel according to the present invention.

Description of the element reference numerals

10 Flexible laminate structure

101 flexible substrate

102 layer of flexible material

11 groove structure

12 printing working platform

13 seed ink

14 scraper

2 printing working platform

3 Soft pad

4 drive layer structure

41 first flexible laminate structure

411 first flexible substrate

412 a first layer of flexible material

413 first groove structure

42 seed ink

43 first seed layer

44 first metal grid

441 first metal line

5 knife coating tool

6 first optical adhesive layer

7 inductive layer structure

71 second flexible laminate structure

711 second flexible substrate

712 second layer of flexible material

713 second groove structure

72 second seed layer

73 second metal grid

731 second metal line

81 second transparent optical adhesive layer

82 transparent cover layer

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 2 to 17. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the type, quantity and proportion of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

Referring to fig. 2, the present embodiment provides a method for manufacturing a touch screen, where the method for manufacturing a touch screen includes the steps of:

1) providing a printing working platform, wherein a soft gasket is arranged on the upper surface of the printing working platform;

2) arranging a first flexible laminated structure on the upper surface of the soft gasket, wherein the first flexible laminated structure comprises a first flexible substrate and a first flexible material layer, the first flexible substrate is positioned on the upper surface of the soft gasket, the first flexible material layer is positioned on the upper surface of the first flexible substrate, and a plurality of first groove structures are formed on the upper surface of the first flexible material layer;

3) the preparation method of the seed ink comprises the following steps:

4) placing a seed ink on an upper surface of the first layer of flexible material; using a blade coating tool to blade coat the seed ink so that the seed ink is filled in each first groove structure to form a first seed layer;

5) forming first metal wires in the first groove structure based on the first seed layer, wherein the first metal wires are connected with each other to form a first metal grid; the first flexible laminated structure, the first seed layer and the first metal grid form a driving layer structure together;

6) forming a first transparent optical adhesive layer on the upper surface of the driving layer structure;

7) arranging a second flexible laminated structure on the upper surface of the soft gasket, wherein the second flexible laminated structure comprises a second flexible substrate and a second flexible material layer, the second flexible substrate is positioned on the upper surface of the soft gasket, the second flexible material layer is positioned on the upper surface of the second flexible substrate, and a plurality of second groove structures are formed on the upper surface of the second flexible material layer;

8) placing seed ink on the upper surface of the second flexible material layer, and carrying out blade coating on the seed ink by using the blade coating tool so that the seed ink is filled in each second groove structure to form a second seed layer;

9) forming second metal wires in each second groove structure based on the second seed layer, wherein the second metal wires are connected with each other to form a second metal grid; the second flexible laminated structure, the second seed layer and the second metal grid form an induction layer structure together;

10) the sensing layer structure is attached to the upper surface of the first transparent optical adhesive layer;

11) forming a second transparent optical adhesive layer on the upper surface of the sensing layer structure;

12) and providing a transparent cover layer, and attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer.

In step 1), please refer to step S1 in fig. 2 and fig. 3, a printing platform 2 is provided, and the upper surface of the printing platform 2 is provided with a soft pad 3.

By way of example, the printing platform 2 may comprise a metal platform, and in particular, the printing platform 2 may comprise an aluminum platform, a stainless steel platform, an aluminum alloy platform, or the like.

As an example, the upper surface of the printing platform 2 is not absolutely flat, i.e. the flatness of the upper surface of the printing platform 2 may not be good, i.e. a part of the upper surface of the printing platform 2 may be formed with pits (not shown) or raised structures.

As an example, the soft pad 3 may be attached to the upper surface of the printing work platform 2 through, but not limited to, an attaching process.

As an example, the soft pad 3 may include a pad having a shore a hardness of 30 degrees to 80 degrees. It should be noted that "between 30 degrees and 80 degrees" as used herein means a range including all values of 30 degrees, 80 degrees and 30 degrees to 80 degrees, i.e., the "between 30 degrees and 80 degrees" as used herein means a range including the endpoints.

As an example, the soft gasket 3 may include a rubber pad, a rubber blanket, a silicon rubber pad, or the like.

As an example, the thickness of the soft pad 3 may be set according to actual needs, and preferably, in this embodiment, the thickness of the soft pad 3 may include 0.5 millimeters (mm) to 10 mm.

Step 2), referring to step S2 in fig. 2 and fig. 4, a first flexible laminated structure 41 is disposed on the upper surface of the soft pad 3, where the first flexible laminated structure 41 includes a first flexible substrate 411 and a first flexible material layer 412, the first flexible substrate 411 is located on the upper surface of the soft pad 3, the first flexible material layer 412 is located on the upper surface of the first flexible substrate 411, and a plurality of first groove structures 413 are formed on the upper surface of the first flexible material layer 412.

As an example, the first groove structure 413 may be formed on the upper surface of the first flexible material layer 412 by using an imprinting process.

As an example, the first flexible substrate 411 may include, but is not limited to, a polyethylene terephthalate (PET) substrate, a Polyimide (PI) substrate, a Polycarbonate (PC) substrate, or a Polymethylmethacrylate (PMMA) substrate.

As an example, the first flexible material layer 412 may include a photoresist layer or a UV (ultraviolet) resin layer. The UV resin layer is also referred to as a photosensitive resin layer and an ultraviolet-curable resin layer, and can be used as a sizing material for paint, coating, ink, and the like. UV is an abbreviation for Ultraviolet Rays, English, i.e., Ultraviolet light. The ultraviolet ray is invisible to naked eyes, is a section of electromagnetic radiation except visible light, and has the wavelength ranging from 10nm to 400 nm. The curing principle of the UV resin layer is that a photoinitiator (or photosensitizer) in the UV resin generates active free radicals or cations after absorbing ultraviolet light under the irradiation of ultraviolet rays, and the polymerization, crosslinking and grafting chemical reactions of monomers are initiated, so that the UV resin layer is converted from a liquid state to a solid state within a few seconds.

As an example, the width and the depth of the first groove structure 413 may be set according to actual needs, and preferably, the depth of the first groove structure 413 may include 1 micron to 20 microns, and the width of the first groove structure 413 may include 1 micron to 10 microns.

As an example, each of the first groove structures 413 may be interconnected in a grid shape, and in particular, the first groove structures 413 may be interconnected in a rectangular grid shape, a rhombic grid shape, a triangular grid shape, a pentagonal grid shape, a hexagonal grid shape, or the like.

As an example, while the first groove structure 413 is formed on the upper surface of the first flexible material layer 412, a first lead groove (not shown) is formed on the upper surface of the first flexible material layer 412, and the first lead groove is communicated with the first groove structure 413. Specifically, one end of the first lead groove is communicated with the first groove structure 413, and the other end of the first lead groove extends to a side edge of the first flexible material layer 412, so as to lead the first groove structure 413 out of at least one side of the first flexible material layer 412.

In step 3), please refer to step S3 in fig. 2, the seed ink 42 is prepared.

As an example, step 3) may comprise the steps of:

3-1) providing iron powder and a first organic solvent, and uniformly mixing the iron powder and part of the first organic solvent under a reducing atmosphere to obtain a first mixture;

3-2) providing a high molecular polymer, a second organic solvent and a defoaming agent, and mixing the high molecular polymer, the second organic solvent and the defoaming agent to obtain a second mixture;

3-3) providing nano silicon dioxide powder, and uniformly mixing the nano silicon dioxide powder and part of the second mixture with the first mixture to obtain a third mixture;

3-4) grinding the third mixture to enable the nano silicon dioxide powder to be in sufficient contact with the iron powder so as to obtain slurry of the iron powder with the surface coated with the silicon dioxide layer;

3-5) continuously adding the first organic solvent, the second mixture and the auxiliary agent into the slurry, and uniformly mixing to obtain the seed ink 42.

As an example, the iron powder provided in step 3-1) may be iron powder obtained by a method of reducing iron oxide to zero-valent iron using a reducing gas (e.g., hydrogen) under high temperature conditions. The "high temperature condition" refers to a temperature condition at which the reducing gas can chemically react with the iron oxide.

As an example, in step 3-1), the iron powder may be added into the first organic solvent while stirring, or the iron powder may be added into the first organic solvent and then stirred, and the specific stirring time and stirring rate may be selected according to actual needs, which is not limited herein.

As an example, the particle size of the iron powder provided in step 3-1) may be selected according to actual needs, and preferably, in this embodiment, the iron powder is a nano iron powder, and the particle size of the iron powder includes 0.2 nm to 5 μm.

As an example, the reducing atmosphere in step 3-1) may include a hydrogen atmosphere, i.e., the iron powder is added to the first organic solvent under a hydrogen protective atmosphere. The iron powder is added into the first organic solvent under a reducing atmosphere, so that the iron powder is ensured not to be contacted with oxygen and not to be oxidized in the adding process.

As an example, in step 3-1), the first organic solvent may include a lipid solvent, an ether solvent, an alcohol solvent, or a ketone solvent, etc.; specifically, the first organic solvent may include, but is not limited to, ethyl acetate, methyl ethyl ketone, dipropylene glycol methyl ether acetate, butyl carbitol acetate, diethylene glycol ethyl ether, propylene glycol methyl ether acetate, ethanol, alpha terpineol, and butyl carbitol; in addition, the first organic solvent may also be propylene glycol methyl ether, dipropylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, a amyl acetate mixture, n-butyl acetate, isobutyl acetate, n-propyl acetate, isopropyl acetate, n-butyl propionate, ethyl 3-ethoxypropionate, dibutyl phthalate, n-pentyl propionate, n-propyl propionate, dibasic esters, acetone, β -terpineol, hexylene glycol, a amyl alcohol mixture, n-butanol, isobutanol, isopropanol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, n-pentanol, n-propanol, or trimethylnonanol.

As an example, in the first mixture obtained in step 3-1), the mass ratio of the first organic solvent to the iron powder may include 0.5 to 10, that is, the mass of the first organic solvent used is 0.5 to 10 times the mass of the iron powder added to the first organic solvent, and preferably, in the present embodiment, the mass ratio of the first organic solvent to the iron powder is 2, that is, the mass of the first organic solvent used is 2 times the mass of the iron powder added to the first organic solvent.

Adding the iron powder into the first organic solvent in a reducing atmosphere, stirring and mixing uniformly to enable the surface of the iron powder to be fully soaked in the first organic solvent, and avoiding the contact of the iron powder and oxygen in the subsequent preparation process, so that the iron powder is prevented from being oxidized, the iron powder is always kept in a reduction valence state, and good reduction performance is kept.

As an example, the step 3-2) of providing a high molecular polymer, a second organic solvent and a defoaming agent, and mixing the high molecular polymer, the second organic solvent and the defoaming agent to obtain a second mixture may include the steps of:

3-2-1) providing the high molecular polymer and the second organic solvent, adding the high molecular polymer into the second organic solvent, stirring and at least heating until the high molecular polymer is completely dissolved to obtain a mixed solution;

3-2-2) providing the defoaming agent, adding the defoaming agent into the mixed solution, stirring and vacuumizing to remove oxygen dissolved in the mixed solution.

As an example, in the step 3-2-1), the temperature for heating after adding the high molecular polymer into the second organic solvent includes 40 ℃ to 90 ℃; after the high molecular polymer is completely dissolved in the second organic solvent, heating is continued for 5 hours to 10 hours, preferably, in this embodiment, after the high molecular polymer is completely dissolved in the second organic solvent, heating is continued for 8 hours.

As an example, the second organic solvent may be heated using a heating mantle using an oil bath, a water bath.

As an example, in the step 3-2-2), in the process of removing the oxygen dissolved in the solution, the environment where the solution is located is pumped to negative pressure, and the pressure is maintained for 2 to 3 hours; the environment of the solution can be pumped to 0 MPa-0.1 MPa.

As an example, the second organic solvent provided in step 3-2) may include: ethyl acetate, methyl ethyl ketone, dipropylene glycol methyl ether carbonate, butyl carbitol acetate, diethylene glycol ethyl ether, propylene glycol methyl ether carbonate, ethanol, alpha terpineol, butyl carbitol, propylene glycol methyl ether, dipropylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, a mixture of amyl acetates, n-butyl acetate, isobutyl acetate, n-propyl acetate, isopropyl acetate, n-butyl propionate, ethyl 3-ethoxypropionate, dibutyl phthalate, n-pentyl propionate, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexylene glycol, a mixture of amyl alcohols, n-butanol, isobutanol, isopropanol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, amyl alcohol, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexyl glycol, amyl alcohol, a mixture of amyl alcohol, n-butanol, isobutanol, isopropyl alcohol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, ethyl acetate, butyl alcohol, butyl, N-pentanol, n-propanol or trimethylnonanol.

As an example, the high molecular polymer provided in step 3-2) may include: polyurethane, polycarbonate, polyvinyl chloride, polymethyl methacrylate, phenoxy resin, polyester, ethylene copolymer; wherein the polyester comprises polyethylene terephthalate, polybutylene terephthalate, polydiallyl terephthalate, polyparahydroxybenzoic acid ester, unsaturated polyester resin, phenolic resin or acrylic resin; the ethylene copolymer includes a polymer obtained by copolymerizing two or more vinyl group-containing monomers.

As an example, the defoaming agent provided in step 3-2) may include: higher alcohol organic compounds, polyether organic compounds or silicon organic compounds. Specifically, the higher alcohol organic compound may include phenethyl alcohol oleate or lauryl phenylacetate, and the like; the polyether organic compound may include: GP type defoaming agents, GPE type defoaming agents, GPEs type defoaming agents, or the like; the silicon-based organic compound may include: polydimethylsiloxane or polyether modified silicon, and the like.

Firstly, the high molecular polymer is dissolved in the second organic solvent and then added into the first mixture together with the nano silicon dioxide powder in the subsequent steps, and the coating of the first organic solvent on the iron powder is not damaged because the high molecular polymer is dissolved in the second organic solvent, so that the iron powder can be prevented from being oxidized; meanwhile, the oxygen dissolved in the mixed solution can be removed by adding the defoaming agent, so that no oxygen exists in a third mixture formed by subsequent mixing, and further, the iron powder is prevented from being oxidized.

As an example, the particle size of the nano-silica powder provided in step 3-3) may be selected according to actual needs, and preferably, in this embodiment, the particle size of the nano-silica powder is less than 100 nm.

As an example, in the third mixture obtained in step 3-3), the mass ratio of the nano silica powder to the iron powder may include 0.1 to 3, that is, the mass of the nano silica powder added to the first mixture is 0.1 to 3 times of the mass of the iron powder in the first mixture, and preferably, in the present embodiment, the mass ratio of the nano silica powder to the iron powder is 0.5, that is, the mass of the nano silica powder added to the first mixture is 0.5 times of the mass of the iron powder in the first mixture.

As an example, the third mixture may be ground in step 3-4) by, but not limited to, a three-roll grinder, during which the distance between the rolls is adjusted to ensure that there is sufficient pressure to make the nano-silica powder and the iron powder contact each other sufficiently, so that the nano-silica powder is adsorbed on the surface of the iron powder by physical adsorption to coat a silica layer on the surface of the iron powder; the silicon dioxide layer is formed by mutual attraction of charge interaction and has a durable characteristic; and the silicon dioxide layer coated on the periphery of the iron powder has a repulsive action on oxygen, so that the contact of the oxygen and the iron powder can be prevented, and the reaction with the iron powder can not occur, thereby ensuring the zero-valent chemical valence state of the iron powder and ensuring that the iron powder has better reduction characteristic. And a three-roll grinder is adopted to grind the third mixture, so that the grinding speed is high, the yield is high, and the energy consumption is low.

By way of example, the spacing between the rollers in the three-roller mill may comprise 1 micron to 25 microns during the milling process.

As an example, the grinding time for grinding the third mixture may be selected according to actual needs, and preferably, in this embodiment, the grinding time for grinding the third mixture may include 0.5 hours to 24 hours.

As an example, the auxiliary agent provided in steps 3-5) may act as a dispersant.

As an example, in step 3-5), the first organic solvent, the second mixture and the auxiliary agent are added to the slurry while or after the first organic solvent, the second mixture and the auxiliary agent are added to the slurry.

By way of example, the adjuvants may include: cationic, anionic, nonionic or amphoteric auxiliaries.

As an example, the cationic adjuvant may include polyethyleneimine, dioctadecyl dimethyl ammonium chloride, or imidazoline quaternary ammonium salt; the anionic adjuvant may include soy lecithin; the non-ionic auxiliary agent can comprise fatty alcohol-polyoxyethylene ether; the amphoteric adjuvant may include cocosulfopropyl betaine.

As an example, the seed ink 42 obtained in step 3-5) may include the following components in percentage by mass: 10 to 90 percent of iron powder coated with a silicon dioxide layer on the surface; 5 to 50 percent of high molecular polymer; 10 to 50 percent of organic solvent; 0.1 to 10 percent of auxiliary agent; 0.01 to 10 percent of defoaming agent.

Preferably, the seed ink 42 may include, in percentage by mass: 50 to 80 percent of iron powder coated with a silicon dioxide layer on the surface, 5 to 15 percent of high molecular polymer, 15 to 35 percent of organic solvent, 0.05 to 1 percent of defoaming agent and 0.1 to 1 percent of auxiliary agent; more preferably, the seed ink 42 may include, by mass percent: 60 to 70 percent of iron powder coated with a silicon dioxide layer on the surface, 8 to 10 percent of high molecular polymer, 25 to 30 percent of organic solvent, 0.05 to 0.5 percent of defoaming agent and 0.1 to 1 percent of auxiliary agent; more preferably, in an example, the seed ink 42 may include, by mass percent: 63% of iron powder coated with a silicon dioxide layer, 9.4% of high molecular polymer, 36% of organic solvent, 0.1% of defoaming agent and 0.5% of auxiliary agent.

The surface of the iron powder in the seed ink 42 prepared by the invention is coated with the silicon dioxide layer, the silicon dioxide layer is adsorbed on the surface of the iron powder through physical adsorption, the silicon dioxide layer has the characteristic of lasting coating, and the silicon dioxide layer has a repulsive effect on oxygen and can prevent the contact of the oxygen and the iron powder, so that the zero-valent chemical valence state of the iron powder is ensured, the iron powder is kept at high reducibility, the iron powder in a seed layer formed based on the seed ink 42 is kept at high reducibility, the broken wire of a metal wire formed based on the seed layer is avoided, and the performance of a first metal grid and a second metal grid formed subsequently is ensured.

It should be noted that the sequence of step 3) and step 2) may be interchanged, that is, the conventional step 3) may be performed first and then the conventional step 2) may be performed, that is, the seed ink 42 may be prepared first and then the first flexible laminated structure 41 may be disposed on the upper surface of the soft pad 3.

In step 4), please refer to step S4 in fig. 2 and fig. 5 to 7, a seed ink 42 is disposed on the upper surface of the first flexible material layer 412; the seed ink 42 is drawn by using a drawing tool 5, so that the seed ink 42 is filled in each of the first groove structures 413 to form a first seed layer 43.

As an example, the seed ink 42 may be dropped onto the upper surface of the first flexible material layer 412.

As an example, the seed ink 42 may be dropped on any position of the upper surface of the first flexible material layer 412, and in this embodiment, the seed ink 42 may be dropped on one side of the plurality of first groove structures 413, so that the seed ink may be scraped from one side of the upper surface of the first flexible material layer 412 to the other side of the upper surface of the first flexible material layer 412 during the subsequent scraping.

By way of example, the blade coating tool 5 may include, but is not limited to, a doctor blade; the structure of the scraper is known to the person skilled in the art and will not be described again here.

As an example, during the doctor blade coating process, the doctor blade tool 5 is used for doctor blade coating the seed ink 42 in a posture inclined at a certain angle with respect to the upper surface of the first flexible material layer 412, preferably, in this embodiment, an included angle between the doctor blade tool 5 and the upper surface of the first flexible material layer 412 may be set according to actual needs, preferably, in this embodiment, an included angle between the doctor blade tool 5 and the upper surface of the first flexible material layer 412 may include 30 ° to 70 °, and more preferably, in this embodiment, an included angle between the doctor blade tool 5 and the upper surface of the first flexible material layer 412 may include 60 ° to 70 °.

As an example, in this step, when the doctor blade tool 5 is used to scrape the seed ink 42, the doctor blade tool 5 applies a preset pressure to the first flexible material layer 412, and preferably, in this embodiment, the doctor blade pressure applied to the first flexible material layer 412 by the doctor blade tool 5 during the doctor blade process may include 4 kilograms of force per square centimeter to 6 kilograms of force per square centimeter.

As an example, the coating speed of the coating tool 5 during coating can be set according to actual needs, preferably, the coating speed of the coating tool 5 for coating the seed ink 42 can include 50 mm per second to 260 mm per second, and more preferably, the coating speed of the coating tool 5 for coating the seed ink 42 can include 160 mm per second to 260 mm per second.

The first flexible laminated structure 41 is placed on the upper surface of the printing working platform 2 provided with the soft pad 3 for scrape coating of the seed ink 42, due to the existence of the soft pad 3, when the scrape coating tool 5 is used for scrape coating of the seed ink 42, under the action of scrape coating pressure, the soft pad 3 can absorb the local unevenness factor of the printing working platform 2, so that the seed ink 42 is prevented from remaining on the surface of the first flexible material layer 412, the cleanliness of the upper surface of the first flexible material layer 412 after the scrape coating is completed is ensured, and the upper surface of the first flexible material layer 412 is cleaned without an additional cleaning step, so that the process flow is simplified, and the production cost is reduced.

As an example, after the seed ink 42 is drawn down to fill each of the first groove structures 413, a step of curing the seed ink 42 is further included. Specifically, when the seed ink 42 is a seed ink, the seed ink 42 may be baked to cure the seed ink 42 to form the first seed layer 43, as shown in fig. 7.

For example, the seed ink 42 is drawn and filled in each of the first groove structures 413, and the seed ink 42 is drawn and filled in the first lead grooves, that is, the first seed layer 43 is formed in the first groove structures 413 and the first lead grooves at the same time.

In step 5), referring to step S5 in fig. 2 and fig. 8, first metal lines 441 are formed in the first groove structure 413 based on the first seed layer 43, and the first metal lines 441 are connected to each other to form a first metal grid 44; the first flexible stacked structure 41, the first seed layer 43 and the first metal mesh 44 together form a driving layer structure 4.

As an example, an electroplating process or an electroless plating process may be used to form a conductive material in each of the first groove structures 413 as the first metal lines 441. Specifically, the first seed layer 43 is immersed in sulfuric acidCopper (CuSO)₄) In the solution, since the diameter of copper ions (about 0.15 nm) is much smaller than the gap in the silicon oxide layer in the first seed layer 43, the copper ions can pass through the gap in the silicon oxide layer to contact the iron powder surface in the silicon oxide layer, so that the zero-valent metallic copper grows through the oxidation-reduction reaction with the iron powder in the silicon oxide layer to form the first metal line 441.

For example, the sum of the thicknesses of the first metal line 441 and the first seed layer 43 is less than or equal to the depth of the first groove structure 413, and preferably, in this embodiment, the sum of the thicknesses of the first metal line 441 and the first seed layer 43 is equal to the depth of the first groove structure 413, that is, in the process of forming the first metal line 441, the conductive material is filled in each of the first groove structures 413 by using an electroplating process or an electroless plating process until the conductive material fills the first groove structures 413.

As an example, the width of the first metal line 441 may be the same as the width of the first groove structure 413, that is, the width of the first metal line 441 may be 1 to 10 micrometers.

As an example, the material of the first metal line 441 may include, but is not limited to, copper, that is, the first metal line 441 may include, but is not limited to, copper metal line.

By way of example, the first metal mesh 44 may include a rectangular metal mesh, a diamond-shaped metal mesh, a triangular metal mesh, a pentagonal metal mesh, a hexagonal metal mesh, or the like.

As an example, while the first metal line 441 is formed in the first groove structure 413, a first lead (not shown) is formed in the first lead groove, and the first lead is connected to the first metal line 441. Specifically, one end of the first lead is connected to the first metal line 441, and the other end of the first lead extends to a side edge of the first flexible material layer 412, so as to lead the first metal line 441 out from at least one side of the first flexible material layer 412.

In step 6), please refer to step S6 in fig. 2 and fig. 9, a first transparent optical glue layer 6 is formed on the upper surface of the driving layer structure 4.

As an example, but not limited to, a spin coating process may be used to form the first transparent optical adhesive layer 6 on the upper surface of the driving layer structure 4, and specifically, all the first transparent optical adhesive layers 6 are formed on the upper surfaces of the first flexible material layer 412 and the first metal grid 44.

By way of example, the first transparent optical adhesive layer 6 may include, but is not limited to, an oca (optical Clear adhesive) optical adhesive layer.

As an example, the first transparent optical glue layer 6 may cover the entire upper surface of the driving layer structure 4.

In step 7), please refer to step S7 in fig. 2 and fig. 10, a second flexible laminated structure 71 is disposed on the upper surface of the soft pad 3, the second flexible laminated structure 71 includes a second flexible substrate 711 and a second flexible material layer 712, the second flexible substrate 711 is located on the upper surface of the soft pad 3, the second flexible material layer 712 is located on the upper surface of the second flexible substrate 711, and a plurality of second groove structures 713 are formed on the upper surface of the second flexible material layer 712.

As an example, the second groove structure 713 may be formed on the upper surface of the second flexible material layer 712 using an imprinting process.

As an example, the second flexible substrate 711 may include, but is not limited to, a polyethylene terephthalate (PET) substrate, a Polyimide (PI) substrate, a Polycarbonate (PC) substrate, or a Polymethylmethacrylate (PMMA) substrate.

As an example, the second flexible material layer 712 may include a photoresist layer or a UV (ultraviolet) resin layer. The UV resin layer is also referred to as a photosensitive resin layer and an ultraviolet-curable resin layer, and can be used as a sizing material for paint, coating, ink, and the like. UV is an abbreviation for Ultraviolet Rays, English, i.e., Ultraviolet light. The ultraviolet ray is invisible to naked eyes, is a section of electromagnetic radiation except visible light, and has the wavelength ranging from 10nm to 400 nm. The curing principle of the UV resin layer is that a photoinitiator (or photosensitizer) in the UV resin generates active free radicals or cations after absorbing ultraviolet light under the irradiation of ultraviolet rays, and the polymerization, crosslinking and grafting chemical reactions of monomers are initiated, so that the UV resin layer is converted from a liquid state to a solid state within a few seconds.

As an example, the width and the depth of the second groove structure 713 may be set according to actual needs, and preferably, the depth of the second groove structure 713 may include 1 micron to 20 microns, and the width of the second groove structure 713 may include 1 micron to 10 microns.

As an example, each of the second groove structures 713 may be interconnected in a lattice shape, and specifically, the second groove structures 713 may be interconnected in a rectangular lattice shape, a rhombic lattice shape, a triangular lattice shape, a pentagonal lattice shape, a hexagonal lattice shape, or the like.

As an example, while the second groove structure 713 is formed on the upper surface of the second flexible material layer 712, a second lead groove (not shown) is formed on the upper surface of the second flexible material layer 712, and the second lead groove is communicated with the second groove structure 713. Specifically, one end of the second lead groove is communicated with the second groove structure 713, and the other end of the second lead groove extends to a side edge of the second flexible material layer 712, so as to lead out the second groove structure 713 from at least one side of the second flexible material layer 712.

In step 8), referring to step S8 in fig. 2 and fig. 11 to 13, a seed ink 42 is disposed on the upper surface of the second flexible material layer 712, and the seed ink 42 is drawn down by using the drawing tool 5, so that the seed ink 42 is filled in each of the second groove structures 713 to form a second seed layer 72.

As an example, the seed ink 42 may be dropped onto the upper surface of the second flexible material layer 712.

As an example, the seed ink 42 may be dropped on any position of the upper surface of the second flexible material layer 712, and in this embodiment, the seed ink 42 may be dropped on one side of the second groove structures 713, so that the seed ink may be scraped from one side of the upper surface of the second flexible material layer 712 to the other side of the upper surface of the second flexible material layer 712 during the subsequent scraping.

As an example, during the knife coating process, the knife coating tool 5 is used for knife coating the seed ink 42 in a posture inclined at a certain angle compared with the upper surface of the second flexible material layer 712, preferably, in this embodiment, an included angle between the knife coating tool 5 and the upper surface of the second flexible material layer 712 may be set according to actual needs, preferably, in this embodiment, an included angle between the knife coating tool 5 and the upper surface of the second flexible material layer 712 may include 30 ° to 70 °, and more preferably, in this embodiment, an included angle between the knife coating tool 5 and the upper surface of the second flexible material layer 712 may include 60 ° to 70 °.

As an example, in this step, when the doctor blade tool 5 is used to scrape the seed ink 42, the doctor blade tool 5 applies a preset pressure to the second flexible material layer 712, and preferably, in this embodiment, the doctor blade pressure applied to the second flexible material layer 712 by the doctor blade tool 5 during the doctor blade process may include 4 kilograms of force per square centimeter to 6 kilograms of force per square centimeter.

The second flexible laminated structure 71 is placed on the upper surface of the printing working platform 2 provided with the soft pad 3 for scrape coating of the seed ink 42, due to the existence of the soft pad 3, when the scrape coating tool 5 is used for scrape coating of the seed ink 42, under the action of scrape coating pressure, the soft pad 3 can absorb the local unevenness factor of the printing working platform 2, so that the seed ink 42 is prevented from remaining on the surface of the second flexible material layer 712, the cleanliness of the upper surface of the second flexible material layer 712 after the scrape coating is completed is ensured, and the upper surface of the second flexible material layer 712 is cleaned without an additional cleaning step, so that the process flow is simplified, and the production cost is reduced.

As an example, after the seed ink 42 is drawn down to fill each of the second groove structures 713, a step of curing the seed ink 42 is further included. Specifically, when the seed ink 42 is a seed ink, the seed ink 42 may be baked to cure the seed ink 42 to form the second seed layer 72, as shown in fig. 13.

For example, the seed ink 42 is drawn and filled in each of the second groove structures 713, and the seed ink 42 is drawn and filled in the second lead grooves, that is, the second seed layer 72 is formed in the second groove structures 713 and the second lead grooves at the same time.

In step 9), referring to step S9 in fig. 2 and fig. 14, second metal lines 731 are formed in each of the second groove structures 713 based on the second seed layer 72, and the second metal lines 731 are connected to each other to form a second metal grid 73; the second flexible stacked structure 71, the second seed layer 72 and the second metal mesh 73 together form an inductive layer structure 7.

As an example, an electroplating process or an electroless plating process may be used to form a conductive material in each of the second groove structures 713 as the second metal lines 731. Specifically, the second seed layer 72 is immersed in copper sulfate (CuSO)₄) In the solution, since the diameter of copper ions (about 0.15 nm) is much smaller than the gap in the silicon dioxide layer in the second seed layer 72, copper ions can pass through the gap in the silicon dioxide layer to contact the iron powder surface in the silicon dioxide layer, so that zero-valent metallic copper grows through oxidation-reduction reaction with the iron powder in the silicon dioxide layer to form the second metal wire 731.

As an example, the sum of the thicknesses of the second metal line 731 and the second seed layer 72 is less than or equal to the depth of the second groove structure 713, and preferably, in this embodiment, the sum of the thicknesses of the second metal line 731 and the second seed layer 72 is equal to the depth of the second groove structure 713, that is, in the process of forming the second metal line 731, the conductive material is filled in each of the second groove structures 713 by using an electroplating process or an electroless plating process until the conductive material fills up the second groove structures 713.

As an example, the width of the second metal line 731 may be the same as the width of the second groove structure 713, i.e., the width of the second metal line 731 may be 1 to 10 micrometers.

As an example, the material of the second metal line 731 may include, but is not limited to, copper, i.e., the second metal line 731 may include, but is not limited to, copper metal line.

As an example, the second metal mesh 73 may include a rectangular metal mesh, a diamond-shaped metal mesh, a triangular metal mesh, a pentagonal metal mesh, a hexagonal metal mesh, or the like.

As an example, while the second metal line 731 is formed in the second groove structure 713, a second lead (not shown) is formed in the second lead groove, and the second lead is connected to the second metal line 731. Specifically, one end of the second lead is connected to the second metal line 731, and the other end of the second lead extends to a side of the second flexible material layer 712, so as to lead out the second metal line 731 from at least one side of the second flexible material layer 712.

It should be noted that, step 6) may also be interchanged with the sequence of step 7) to step 9), that is, the existing step 7) to step 9) may also be performed first, and then the existing step 6) is performed, that is, the sensing layer structure 7 may also be prepared first, and then the first transparent optical adhesive layer 6 is formed on the upper surface of the driving layer structure 4.

In step 10), please refer to step S10 in fig. 2 and fig. 15, the sensing layer structure 7 is attached to the upper surface of the first transparent optical adhesive layer 6.

As an example, the upper surface of the second flexible substrate 711 is in contact with the upper surface of the first transparent optical adhesive layer 6. The sensing layer structure 7 is attached and fixed on the driving layer structure 4 through the first transparent optical adhesive layer 6.

In step 11), please refer to step S11 in fig. 2 and fig. 16, a second transparent optical adhesive layer 81 is formed on the upper surface of the sensing layer structure 7.

As an example, but not limited to, a spin coating process may be used to form the second transparent optical adhesive layer 81 on the upper surface of the sensing layer structure 7, and specifically, all the second transparent optical adhesive layers 81 are formed on the upper surfaces of the second flexible material layer 712 and the second metal mesh 73.

As an example, the second transparent optical adhesive layer 81 may include, but is not limited to, an oca (optical Clear adhesive) optical adhesive layer.

As an example, the second transparent optical glue layer 81 may cover the entire upper surface of the sensing layer structure 7.

In step 12), please refer to step S12 in fig. 2 and fig. 17, a transparent cover layer 82 is provided, and the transparent cover layer 82 is attached to the upper surface of the second transparent optical adhesive layer 81.

By way of example, the transparent cover layer 82 may include, but is not limited to, a glass cover plate. The transparent cover layer 82 is attached to the sensing layer structure 7 through the second optical adhesive layer 8.

As an example, the transparent cover layer 82 may completely cover the second transparent optical adhesive layer 81.

As an example, the step 12) is followed by the following steps:

13) providing a flexible circuit board (FPC) (not shown) and a processing chip (not shown);

14) coupling the flexible circuit board with the first metal grid 44, the second metal grid 73 and the processing chip such that the first metal grid 44 and the second metal grid 73 are electrically connected with the processing chip via the flexible circuit board.

As an example, the specific structure of the flexible circuit board and the processing chip provided in step 13) is known to those skilled in the art, and will not be described herein again.

As an example, the first metal mesh 44 is electrically connected to the flexible circuit board via the first lead, and the second metal mesh 73 is electrically connected to the flexible circuit board via the second lead.

In summary, the preparation method of the touch screen of the present invention includes the steps of: providing a printing working platform, wherein a soft gasket is arranged on the upper surface of the printing working platform; arranging a first flexible laminated structure on the upper surface of the soft gasket, wherein the first flexible laminated structure comprises a first flexible substrate and a first flexible material layer, the first flexible substrate is positioned on the upper surface of the soft gasket, the first flexible material layer is positioned on the upper surface of the first flexible substrate, and a plurality of first groove structures are formed on the upper surface of the first flexible material layer; the preparation method of the seed ink comprises the following steps: providing iron powder and a first organic solvent, and uniformly mixing the iron powder and part of the first organic solvent under a reducing atmosphere to obtain a first mixture; providing a high molecular polymer, a second organic solvent and a defoaming agent, and mixing the high molecular polymer, the second organic solvent and the defoaming agent to obtain a second mixture; providing nano silicon dioxide powder, and uniformly mixing the nano silicon dioxide powder, part of the second mixture and the first mixture to obtain a third mixture; grinding the third mixture to enable the nano silicon dioxide powder to be in sufficient contact with the iron powder so as to obtain slurry of the iron powder with the surface coated with the silicon dioxide layer; continuously adding the first organic solvent, the second mixture and the auxiliary agent into the slurry, and uniformly mixing to obtain the seed ink; placing the seed ink on an upper surface of the first layer of flexible material; using a blade coating tool to blade coat the seed ink so that the seed ink is filled in each first groove structure to form a first seed layer; forming first metal wires in the first groove structure based on the first seed layer, wherein the first metal wires are connected with each other to form a first metal grid; the first flexible laminated structure, the first seed layer and the first metal grid form a driving layer structure together; forming a first transparent optical adhesive layer on the upper surface of the driving layer structure; arranging a second flexible laminated structure on the upper surface of the soft gasket, wherein the second flexible laminated structure comprises a second flexible substrate and a second flexible material layer, the second flexible substrate is positioned on the upper surface of the soft gasket, the second flexible material layer is positioned on the upper surface of the second flexible substrate, and a plurality of second groove structures are formed on the upper surface of the second flexible material layer; placing the seed ink on the upper surface of the second flexible material layer, and carrying out blade coating on the seed ink by using the blade coating tool so that the seed ink is filled in each second groove structure to form a second seed layer; forming second metal wires in each second groove structure based on the second seed layer, wherein the second metal wires are connected with each other to form a second metal grid; the second flexible laminated structure, the second seed layer and the second metal grid form an induction layer structure together; the sensing layer structure is attached to the upper surface of the first transparent optical adhesive layer; forming a second transparent optical adhesive layer on the upper surface of the sensing layer structure; and providing a transparent cover layer, and attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer. In the preparation method of the touch screen, when the first seed layer and the second seed layer are prepared, the first flexible laminated structure and the second flexible laminated structure are respectively arranged on the upper surface of the printing working platform provided with the soft liner for blade coating of the seed ink, due to the existence of the soft liner, when a blade coating tool is used for blade coating of the seed ink, the soft liner can absorb the local uneven factors of the printing working platform under the action of blade coating pressure, so that the residue of the seed ink on the surfaces of the first flexible material layer and the second flexible material layer is avoided, the cleanliness of the upper surface of the first flexible material layer and the cleanliness of the upper surface of the second flexible material layer are ensured after the blade coating is finished, an additional step of pre-curing the seed ink and a step of cleaning the upper surface of the first flexible material layer and the upper surface of the second flexible material layer are not required, and the process flow is simplified, the production cost is reduced; the seed ink prepared by the invention adopts iron powder as a raw material, and the iron belongs to base metal, so that the production cost can be reduced; the surface of the iron powder in the seed ink prepared by the invention is coated with the silicon dioxide layer, namely the surface of the iron powder in the first seed layer and the second seed layer is coated with the silicon dioxide layer, the silicon dioxide layer is adsorbed on the surface of the iron powder through physical adsorption, and has the characteristic of lasting coating, and the silicon dioxide layer has the repulsion action on oxygen and can prevent the contact of the oxygen and the iron powder, so that the zero-valent chemical valence state of the iron powder is ensured, the iron powder keeps high reducibility, the disconnection of a first metal wire and a second metal wire formed based on the first seed layer and the second seed layer can be avoided, the performance of a first metal grid and a second metal grid formed is ensured, and the performance of a touch screen is further ensured; when the seed ink is prepared, firstly, the iron powder is added into the first organic solvent in a reducing atmosphere and is uniformly stirred and mixed, so that the surface of the iron powder is fully soaked in the first organic solvent, and the iron powder can be prevented from contacting oxygen in the subsequent preparation process, so that the iron powder is prevented from being oxidized; when the seed ink is prepared, the three-roller grinder is used for grinding the third mixture, so that the grinding speed is high, the yield is high, and the energy consumption is low; when the seed ink is prepared, the high molecular polymer is dissolved in the second organic solvent and then added into the first mixture together with the nano silicon dioxide powder, and the coating of the first organic solvent on the iron powder cannot be damaged because the high molecular polymer is dissolved in the second organic solvent, so that the iron powder can be prevented from being oxidized; when the seed ink is prepared, the high molecular polymer is dissolved in the second organic solvent to obtain a mixed solution, then the defoaming agent is added to remove oxygen dissolved in the mixed solution to obtain a second mixture, and then the second mixture and the nano silicon dioxide powder are added to the first mixture together to form a third mixture, so that the third mixture is ensured to have no oxygen, and further, the iron powder is prevented from being oxidized.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

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

the preparation method of the seed ink comprises the following steps:

providing iron powder and a first organic solvent, and uniformly mixing the iron powder and part of the first organic solvent under a reducing atmosphere to obtain a first mixture; the mass ratio of the first organic solvent to the iron powder is 0.5-10;

2. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: the printing working platform comprises a metal working platform; the soft gasket comprises a gasket with Shore A hardness of 30-80 degrees, and the thickness of the soft gasket is 0.5-10 mm.

3. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: in the process of blade coating the seed ink on the upper surface of the first flexible material layer, an included angle between the blade coating tool and the upper surface of the first flexible material layer is 30-70 degrees, blade coating pressure is 4-6 kilograms of force per square centimeter, and blade coating speed is 50-260 millimeters per second; in the process of blade coating the seed ink on the upper surface of the second flexible material layer, an included angle between the blade coating tool and the upper surface of the second flexible material layer is 30-70 degrees, blade coating pressure is 4-6 kilograms of force per square centimeter, and blade coating speed is 50-260 millimeters per second.

4. The method for preparing a touch screen according to claim 3, wherein the method comprises the following steps: the particle size of the iron powder is 0.2-5 micrometers, and the particle size of the nano silicon dioxide powder is less than 100 nanometers.

5. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: in the first mixture and the third mixture, the mass ratio of the nano silicon dioxide powder to the iron powder is 0.1-3.

6. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: providing a high molecular polymer, a second organic solvent and a defoaming agent, and mixing the high molecular polymer, the second organic solvent and the defoaming agent to obtain a second mixture, wherein the second mixture comprises the following steps:

7. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: adding the high molecular polymer into the second organic solvent, and heating to 40-90 ℃; and after the high molecular polymer is completely dissolved in the second organic solvent, continuously heating for 5-10 hours.

8. The method for preparing the touch screen according to claim 6, wherein in the process of removing the dissolved oxygen in the solution, the environment where the solution is located is pumped to negative pressure, and the pressure is maintained for 2-3 hours.

9. The method for preparing a touch screen according to claim 1, wherein the first organic solvent and the second organic solvent each comprise: ethyl acetate, methyl ethyl ketone, dipropylene glycol methyl ether carbonate, butyl carbitol acetate, diethylene glycol ethyl ether, propylene glycol methyl ether carbonate, ethanol, alpha terpineol, butyl carbitol, propylene glycol methyl ether, dipropylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, a mixture of amyl acetates, n-butyl acetate, isobutyl acetate, n-propyl acetate, isopropyl acetate, n-butyl propionate, ethyl 3-ethoxypropionate, dibutyl phthalate, n-pentyl propionate, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexylene glycol, a mixture of amyl alcohols, n-butanol, isobutanol, isopropanol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, amyl alcohol, n-propyl propionate, dibasic esters, acetone, beta-terpineol, hexyl glycol, amyl alcohol, a mixture of amyl alcohol, n-butanol, isobutanol, isopropyl alcohol, diisobutyl methanol, methyl isobutyl methanol, 2-methyl butanol, ethyl acetate, butyl alcohol, butyl, N-pentanol, n-propanol or trimethylnonanol; the high molecular polymer comprises: polyurethane, polycarbonate, polyvinyl chloride, polymethyl methacrylate, phenoxy resin, polyester, ethylene copolymer; the defoaming agent comprises: higher alcohol organic compounds, polyether organic compounds or silicon organic compounds; the auxiliary agent comprises: cationic, anionic, nonionic or amphoteric auxiliaries.

10. The method for preparing the touch screen according to claim 1, wherein the third mixture is ground by a three-roll grinder, and the distance between the rolls is 1-25 micrometers in the grinding process.

11. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: the depth of the first groove structure is 1-20 micrometers, and the width of the first groove structure is 1-10 micrometers; the sum of the thicknesses of the first metal line and the first seed layer is less than or equal to the depth of the first groove structure, and the width of the first metal line is the same as that of the first groove structure; the depth of the second groove structure is 1-20 micrometers, and the width of the second groove structure is 1-10 micrometers; the sum of the thicknesses of the second metal line and the second seed layer is less than or equal to the depth of the second groove structure, and the width of the second metal line is the same as that of the second groove structure.

12. The method for preparing a touch screen according to claim 1, wherein the method comprises the following steps: first transparent optical cement includes OCA optical cement, the second transparent optical cement includes OCA optical cement, transparent cap layer includes transparent glass.

13. The method for manufacturing a touch screen according to claim 1,

forming a first groove structure on the upper surface of the first flexible material layer, and forming a first lead groove on the upper surface of the first flexible material layer, wherein the first lead groove is communicated with the first groove structure; the first seed layer is formed in the first groove structure and the first lead groove at the same time; forming a first lead in the first lead groove while forming the first metal line in the first groove structure, wherein the first lead is connected with the first metal line;

14. The method for manufacturing the touch screen according to claim 13, wherein the step of attaching the transparent cover layer to the upper surface of the second transparent optical adhesive layer further comprises:

providing a flexible circuit board and a processing chip;

15. The method for preparing the touch screen according to any one of claims 1 to 14, wherein the seed ink comprises the following components in percentage by mass:

10% -90% of iron powder coated with a silicon dioxide layer;

5% -50% of high-molecular polymer;

10% -50% of an organic solvent;

0.1% -10% of an auxiliary agent;

0.01% -10% of defoaming agent.