A manufacturing method of a transparent flexible thin film electrode

Abstract

The present invention relates to the technical field of electronic components, and particularly relates to a manufacturing method of a transparent flexible thin-film electrode, comprising the following steps: (1) pre-treating the surface of a substrate; (2) coating a polyimide slurry on the surface of the pre-treated substrate and curing it to obtain a polyimide layer; (3) opening conductive grooves on the polyimide layer according to the design of an electrode pattern; (4) spraying a heat-conducting ink in the conductive grooves and curing it to obtain a heat-conducting protective layer; (5) filling a nano-silver conductive ink into the conductive grooves sprayed with the heat-conducting ink, and drying and curing; (6) removing the redundant nano-silver conductive ink outside the conductive grooves to obtain an electrode pattern; (7) coating an ultraviolet curing solution on the surface of the polyimide coating after obtaining the electrode pattern and curing it to obtain a transparent encapsulation layer. The electrode prepared by the present invention has a response speed of 2-5 s, a number of bending resistance times of more than 300,000 times, a temperature of 35-50 °C after heating for 72 h, good high-temperature performance, and greatly improved service life.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and particularly to a method for manufacturing a transparent flexible thin film electrode. Background Art

[0002] With the continuous pursuit of human beings for visual enjoyment and improved quality of life, transparent flexible displays and wearable foldable electronic products have been more widely used in meeting the needs under personalized, diversified and complex conditions. A flexible electrode is a thin film material that simultaneously has high light transmittance, high electrical conductivity and bending properties, and is also a core component constituting optoelectronic devices such as solar cells, light-emitting diodes, liquid crystal displays, and touch screens.

[0003] Currently, the most widely used transparent electrode material is metal oxide semiconductor, such as indium tin oxide (ITO), etc. Although it has high electrical conductivity and high transmittance, the production of ITO thin film is limited due to the scarcity of indium content, and the price is also high; at the same time, its inherent brittleness, the complex instruments and high temperature required during preparation greatly limit its application in the field of flexible transparent electrodes. Silver nanowire conductive nanomaterials have been widely studied as transparent electrode materials due to their good electrical conductivity, light transmittance, flexibility, and a series of advantages such as solution processing methods.

[0004] The existing preparation of flexible transparent electrodes of silver nanowires usually adopts the method of coating silver nanowire conductive ink on the whole surface to make a conductive layer, and then laser etching out conductive channels. When laser etching the conductive channels, the silver nanowires will be broken and ablated by the laser, thus forming conductive lines. Observed under a microscope, the edges of the lines etched by the laser are relatively rough, and this roughness will have the following adverse effects on the electrode: First, after making a touch film group, there will be etching marks, affecting the appearance; second, during the operation of the device, when current continuously flows through the transparent electrode, the generated Joule heat will cause the local temperature of the silver nanowires to rise. Especially for devices with poor thermal conductivity of the substrate, the Joule heat generated by the silver nanowires is difficult to diffuse outward through the substrate, further leading to the accumulation of local heat. This Joule heat effect is more serious in damaging the structure and conductivity of silver nanowires than uniform external heating; third, once the encapsulation is poor or in a high-humidity environment, the broken silver nanoparticles will undergo silver migration, resulting in short circuits of the conductive lines and device failure. Therefore, it is an urgent technical problem for those skilled in the art to form a thin film electrode with excellent uniformity, light transmittance, electrical conductivity and smoothness. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a method for manufacturing a transparent flexible thin film electrode, and a transparent flexible electrode with rapid response and long service life is prepared.

[0006] A method for fabricating a transparent flexible thin-film electrode, comprising the following steps:

[0007] (1) Pretreat the surface of the substrate;

[0008] (2) Coat and cure a polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer;

[0009] (3) Open conductive grooves on the polyimide layer according to the electrode pattern design;

[0010] (4) Spray and cure a heat-conducting ink in the conductive grooves to obtain a heat-conducting protective layer;

[0011] (5) Fill the conductive grooves sprayed with the heat-conducting ink with a nano-silver conductive ink, and dry and cure;

[0012] (6) Remove the excess nano-silver conductive ink outside the conductive grooves to obtain an electrode pattern;

[0013] (7) Coat and cure an ultraviolet-curing liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer.

[0014] Further, in step (1), the surface dyne value of the pretreated substrate is controlled to be 40 - 60 mN / m, and in step (2), the thickness of the polyimide layer is 5 - 15 μm. Preferably, in step (1), the surface dyne value of the pretreated substrate is controlled to be 45 - 55 mN / m, and in step (2), the thickness of the polyimide layer is 8 - 12 μm.

[0015] Further, in step (3), the conductive groove is a V-shaped conductive groove, and the V-shaped conductive groove is obtained by laser grooving. Groove grooving is usually single-sided grooving, including but not limited to V-shaped, U-shaped, W-shaped, X-shaped, etc. In this application, the cross-sectional shape of the conductive groove is defined as V-shaped, so as to compact the nano-silver conductive ink by the two walls at the bottom of the V-shaped conductive groove, increase the compaction density, thereby increasing the contact area between the nano-silvers in the ink, and further increasing the number of silver nanowire conductive paths and reducing the line resistance.

[0016] Further, the opening angle of the V-shaped conductive groove is 10° - 80°, and the opening depth is 0.05 - 0.15 μm. Preferably, the opening angle of the V-shaped conductive groove is 30° - 60°, and the opening depth is 0.05 - 0.08 μm.

[0017] Further, in step (4), the thickness of the heat-conducting protective layer is 3 - 10 nm. Preferably, in step (4), the thickness of the heat-conducting protective layer is 5 - 8 nm.

[0018] Further, the heat-conducting ink is composed of the following components:

[0019] Matrix resin: 50 - 65%;

[0020] Dispersant: 0.5 - 1.0%;

[0021] Organic solvent: 10 - 25%;

[0022] Thermal conductive filler: 10 - 25%;

[0023] Coupling agent: 0.5 - 1.0%; and,

[0024] Modified additive: 0.5 - 1.0%.

[0025] Preferably, the thermal conductive ink is composed of the following components:

[0026] Matrix resin: 55%;

[0027] Dispersant: 0.8%;

[0028] Organic solvent: 20%;

[0029] Thermal conductive filler: 20%;

[0030] Coupling agent: 1%; and,

[0031] Modified additive: 0.5 - 1.0%.

[0032] Specifically, the matrix resin is selected from polyimide resins; the dispersant is an organic dispersant, selected from one or more of triethylhexyl phosphate, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, polyacrylamide, guar gum, fatty acid polyethylene glycol esters; the organic solvent is selected from at least one of polyethylene glycol, polyvinyl alcohol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether, methyl ethyl ketone, γ-butyrolactone.

[0033] Further, the thermal conductive filler is selected from one of graphene, silicon carbide, boron nitride, silicon nitride, aluminum nitride, aluminum oxide, zinc oxide; the coupling agent is selected from one of silane coupling agents, titanate coupling agents, aluminate coupling agents, bimetallic coupling agents, phosphate coupling agents, borate coupling agents.

[0034] Further, the modified additive is selected from at least one of octadecylamine, octadecylamine oxide, polydopamine, 1-pyrenebutyric acid, chlorosulfonic acid.

[0035] In the thermal conductive ink, the thermal conductive filler is used as a functional material to play a role in heat conduction, preventing the internal temperature of the electrode from being too high and affecting the electrical conductivity. The coupling agent is mainly used to enhance the adhesion between the thermal conductive protective layer and the polyimide of the conductive groove and the conductive pattern. By adding a modified additive to the thermal conductive ink, it fills and squeezes into the voids between the thermal conductive particles, restricts the relative sliding between the thermal conductive particles, strengthens the interaction force between the mixtures, and plays a role in stabilizing the structure..

[0036] The thermal conductive protective layer is disposed at the bottom of the conductive trench. On the one hand, it can reduce the amount of thermal conductive ink used and prevent the increase of the electrode thickness. On the other hand, it will not cause an increase in contact resistance, thus affecting the response speed and sensitivity of touch control. After adding the thermal conductive layer, heat is fully transferred inside the electrode. As the usage time prolongs, the temperature of the conductive line rises, and the enhanced lattice vibration of the conductive metal (silver nanowire) interferes with the movement of free electrons, resulting in a decrease in the thermal conductivity coefficient. Through the setting of the thermal conductive protective layer, the heat generated inside is fully conducted out, thereby protecting the nano silver wire from breaking due to high temperature and ensuring the high-temperature performance of the electrode.

[0037] Further, in step (6), removing the excess nano silver conductive ink outside the conductive trench specifically includes: coating a release agent on the cured nano silver conductive ink to obtain a release layer, controlling the peel force of the release layer to be 10 - 30 grams, and then peeling off the release layer to remove the excess nano silver conductive ink to obtain the electrode pattern.

[0038] Further, the thickness of the transparent encapsulation layer in step (7) is 100 - 200 nm. Preferably, the thickness of the transparent encapsulation layer in step (7) is 150 nm.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) The manufacturing method of the transparent flexible thin-film electrode provided by the present invention is obtained by pre-coating a thin film on the surface of a transparent optical film substrate, and then fabricating a conductive trench, a thermal conductive protective layer, a conductive line and an encapsulation layer. By presetting a conductive trench on the polyimide and filling nano silver conductive ink in the conductive trench to obtain an electrode pattern, etching of the conductive layer is avoided, thereby preventing the nano silver wire conductive material from being broken and ablated, and further avoiding silver migration of the broken nano silver wire under adverse external conditions, improving the service life of the device. The electrode prepared by the present invention has a response speed of 2 - 5 s, a number of bending resistance times of more than 300,000 times, a temperature of 35 - 50 °C after heating for 72 h, good high-temperature performance, and greatly improved service life.

[0041] (2) The manufacturing method of the transparent flexible thin-film electrode provided by the present invention prefabricates a conductive trench, and can adjust the filling amount of the conductive material by controlling the grooving depth and grooving angle of the trench, so as to achieve the purpose of controlling the line resistance of the electrode; by setting the conductive trench as a V-shaped groove, the V-shaped side wall can be used to compact the conductive ink in the conductive trench, thereby increasing the contact area of the nano silver wires, increasing the conductive path, and further reducing the line resistance of the electrode.

[0042] (3) The manufacturing method of the transparent flexible thin-film electrode provided by the present invention prepares a thermal conductive protective layer by pre-coating thermal conductive ink in the conductive grooves, and then fills conductive ink. The thermal conductive protective layer is used to improve the thermal conductivity of the electrode, preventing local overheating caused by Joule heat generated inside the electrode during device operation, which may affect the electrode performance. Detailed implementation manners

[0043] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0044] Embodiment 1

[0045] (1) Corona pretreatment is performed on the substrate to control the surface dyne value of the substrate within 45 - 55 mN / m;

[0046] (2) Polyimide slurry is coated on the surface of the pretreated substrate and cured to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. Coating film-forming process parameters: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, and the thickness of the polyimide layer is controlled to be 10 um;

[0047] (3) According to the electrode pattern design, conductive grooves are opened on the polyimide layer using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz, and the conductive film is scanned and processed through a scanning galvanometer and an XY moving platform. The grooving angle is controlled at 45°, and the grooving depth is 0.11 um;

[0048] (4) Thermal conductive ink is sprayed into the conductive grooves and cured to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink is composed of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0049] (5) Nano-silver conductive ink is filled into the conductive grooves sprayed with thermal conductive ink, dried and cured. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0050] (6) The excess nano-silver conductive ink outside the V-shaped conductive grooves is removed to obtain an electrode pattern, and peeling is performed by coating a release agent, controlling the peeling force within 20 - 25 grams;

[0051] (7) Coating and curing an ultraviolet curable liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet curable liquid is 10%. Coating and film-forming process parameters: pumping flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer to be 150 nm.

[0052] Example 2

[0053] (1) Corona pre-treat the substrate to control the surface dyne value of the substrate within 40 - 45 mN / m;

[0054] (2) Coating and curing a polyimide slurry on the surface of the pre-treated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. Coating and film-forming process parameters: pumping flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer to be 5 um;

[0055] (3) According to the electrode pattern design, use a laser to open a conductive trench on the polyimide layer. Laser wavelength 278 - 355 nm, output power 10 W, pulse width adjustable from 5 - 500 ns, repetition frequency 20 - 100 KHz, scanning and processing the conductive film through a scanning galvanometer and an XY moving platform, controlling the grooving angle at 30°, and the grooving depth at 0.05 um;

[0056] (4) Spray and cure a thermal conductive ink in the conductive trench to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 3 nm. The thermal conductive ink consists of the following components: 50 parts of polyimide resin, 23 parts of a (ethylene glycol: isopropyl alcohol) mixed solvent with a mass ratio of 1:1, 0.5 part of sodium dodecyl sulfate dispersant, 25 parts of graphene conductive filler, 0.5 part of silane coupling agent, and 1 part of polydopamine modified additive.

[0057] (5) Fill the conductive trench sprayed with the thermal conductive ink with nano-silver conductive ink, and dry and cure it. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 80 °C;

[0058] (6) Remove the excess nano-silver conductive ink outside the V-shaped conductive trench to obtain the electrode pattern, and perform peeling by coating a release agent, controlling the peeling force at 10 - 20 grams;

[0059] (7) Coating and curing an ultraviolet curable liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet curable liquid is 10%. Coating and film-forming process parameters: pumping flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer to be 100 nm.

[0060] Example 3

[0061] (1) Corona-preprocess the substrate to control the surface dyne value of the substrate within 55 - 60 mN / m;

[0062] (2) Coat and cure a polyimide slurry on the surface of the preprocessed substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. Coating film-forming process parameters: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, control the thickness of the polyimide layer to be 12 um;

[0063] (3) Open conductive grooves on the polyimide layer according to the electrode pattern design using a laser. Laser wavelength 278 - 355 nm, output power 10 W, pulse width adjustable from 5 - 500 ns, repetition frequency 20 - 100 KHz. Scan and process the conductive film through a scanning galvanometer and an XY moving platform, control the grooving angle at 60°, and the grooving depth at 0.15 um;

[0064] (4) Spray and cure a heat-conducting ink in the conductive grooves to obtain a heat-conducting protective layer. The thickness of the heat-conducting protective layer is 10 nm. The heat-conducting ink consists of the following components: 65 parts of polyimide resin, 20 parts of a (polyvinyl alcohol: methyl ethyl ketone) mixed solvent with a mass ratio of 1:1, 0.7 part of a fatty acid polyethylene glycol ester dispersant, 12 parts of zinc oxide conductive filler, 0.8 part of a phosphate ester coupling agent, and 1.5 parts of a chlorosulfonic acid-modified additive.

[0065] (5) Fill the conductive grooves sprayed with the heat-conducting ink with a nano-silver conductive ink, dry and cure it. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 80 °C;

[0066] (6) Remove the excess nano-silver conductive ink outside the V-shaped conductive grooves to obtain an electrode pattern, and perform peeling by coating a release agent, control the peeling force at 25 - 30 grams;

[0067] (7) Coat and cure an ultraviolet-curable liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet-curable liquid is 10%. Coating film-forming process parameters: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, control the thickness of the transparent encapsulation layer to be 200 nm.

[0068] Example 4

[0069] This example includes most of the operating steps of Example 1, the difference being that the grooving angle of the conductive groove is 0°, that is, the bottom of the groove is flat. The specific preparation method is as follows:

[0070] (1) Corona-preprocess the substrate to control the surface dyne value of the substrate within 45 - 55 mN / m;

[0071] (2) Coating and curing a polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. Coating and film-forming process parameters: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer to be 10 um;

[0072] (3) According to the design of the electrode pattern, conductive grooves are opened on the polyimide layer. By coating a photosensitive photoresist and performing exposure and development, the conductive grooves are prepared. The grooving angle is 0°, and the grooving depth is 0.11 um;

[0073] (4) Spraying and curing a thermal conductive ink in the conductive grooves to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink is composed of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0074] (5) Filling the conductive grooves sprayed with the thermal conductive ink with nano-silver conductive ink and drying and curing. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0075] (6) Removing the excess nano-silver conductive ink outside the V-shaped conductive grooves to obtain an electrode pattern, and performing peeling by coating a release agent, controlling the peeling force to be 20 - 25 grams;

[0076] (7) Coating and curing an ultraviolet curing liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing liquid is 10%. Coating and film-forming process parameters: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer to be 150 nm.

[0077] Example 5

[0078] This example includes most of the operation steps of Example 1, and the difference is that the grooving angle of the conductive grooves is 80°. The specific preparation method is as follows:

[0079] (1) Corona-pretreating the substrate to control the surface dyne value of the substrate to be 45 - 55 mN / m;

[0080] (2) Coating and curing a polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. Coating and film-forming process parameters: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer to be 10 um;

[0081] (3) Open conductive grooves on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz. The conductive film is scanned and processed through a scanning galvanometer and an XY moving platform, controlling the grooving angle at 80° and the grooving depth at 0.11 um;

[0082] (4) Spray and cure thermal conductive ink in the conductive grooves to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink consists of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0083] (5) Fill the conductive grooves sprayed with thermal conductive ink with nano-silver conductive ink, and dry and cure it. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0084] (6) Remove the excess nano-silver conductive ink outside the V-shaped conductive grooves to obtain the electrode pattern, and strip it by coating a release agent, controlling the stripping force at 20 - 25 grams;

[0085] (7) Coat and cure an ultraviolet curing solution on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing solution is 10%. The coating film forming process parameters are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer at 150 nm.

[0086] Example 6

[0087] This example includes most of the operation steps of Example 1, the difference being that the grooving depth of the conductive grooves is 0.02 um. The specific preparation method is as follows:

[0088] (1) Perform corona pretreatment on the substrate to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0089] (2) Coat and cure polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The coating film forming process parameters are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer at 10 um;

[0090] (3) Conductive grooves are opened on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz. The conductive film is scanned and processed through a galvanometer scanner and an XY moving platform, and the grooving angle is controlled at 45°, and the grooving depth is 0.02 μm;

[0091] (4) Thermal conductive ink is sprayed into the conductive grooves and cured to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink consists of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0092] (5) Nano-silver conductive ink is filled into the conductive grooves sprayed with thermal conductive ink, dried and cured. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0093] (6) The excess nano-silver conductive ink outside the V-shaped conductive grooves is removed to obtain the electrode pattern, and stripping is carried out by coating a release agent, and the stripping force is controlled at 20 - 25 grams;

[0094] (7) An ultraviolet curing liquid is coated on the surface of the polyimide coating after obtaining the electrode pattern and cured to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing liquid is 10%. The process parameters of the coating and film forming are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 μm, and the thickness of the transparent encapsulation layer is controlled at 150 nm.

[0095] Example 7

[0096] This example includes most of the operation steps of Example 1, and the difference is that the grooving depth of the conductive grooves is 0.25 μm. The specific preparation method is as follows:

[0097] (1) The substrate is corona pre-treated to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0098] (2) Polyimide slurry is coated on the surface of the pre-treated substrate and cured to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The process parameters of the coating and film forming are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 μm, and the thickness of the polyimide layer is controlled at 10 μm;

[0099] (3) Conductive grooves are opened on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz. The conductive film is scanned and processed through a scanning galvanometer and an XY moving platform, controlling the grooving angle at 45°, and the grooving depth at 0.25 um;

[0100] (4) Thermal conductive ink is sprayed into the conductive grooves and cured to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink consists of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0101] (5) Nano silver conductive ink is filled into the conductive grooves sprayed with thermal conductive ink, and dried and cured. The Ag content in the nano silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0102] (6) The excess nano silver conductive ink outside the V-shaped conductive grooves is removed to obtain the electrode pattern, and it is peeled off by coating a release agent, controlling the peeling force at 20 - 25 grams;

[0103] (7) An ultraviolet curing solution is coated on the surface of the polyimide coating after obtaining the electrode pattern and cured to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing solution is 10%. The process parameters for coating and film formation are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer at 150 nm.

[0104] Example 8

[0105] This example includes most of the operation steps of Example 1, the difference being that the thickness of the thermal conductive protective layer is 25 nm. The specific preparation method is as follows:

[0106] (1) The substrate is corona pre-treated to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0107] (2) Polyimide slurry is coated on the surface of the pre-treated substrate and cured to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The process parameters for coating and film formation are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer at 10 um;

[0108] (3) Conductive grooves are opened on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, and the repetition frequency is 20 - 100 KHz. The conductive film is scanned and processed through a galvanometer scanner and an XY moving platform, controlling the grooving angle at 45° and the grooving depth at 0.11 um;

[0109] (4) Thermal conductive ink is sprayed into the conductive grooves and cured to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 25 nm. The thermal conductive ink is composed of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0110] (5) Nano-silver conductive ink is filled into the conductive grooves sprayed with thermal conductive ink, dried and cured. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0111] (6) The excess nano-silver conductive ink outside the V-shaped conductive grooves is removed to obtain the electrode pattern, and peeling is carried out by coating a release agent, controlling the peeling force at 20 - 25 grams;

[0112] (7) An ultraviolet curing solution is coated on the surface of the polyimide coating after obtaining the electrode pattern and cured to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing solution is 10%. The coating film forming process parameters are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, and controlling the thickness of the transparent encapsulation layer at 150 nm.

[0113] Example 9

[0114] This example includes most of the operation steps of Example 1, the difference being that the modified additive is not added to the thermal conductive ink of the thermal conductive protective layer. The specific preparation method is as follows:

[0115] (1) The substrate is subjected to corona pretreatment to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0116] (2) Polyimide slurry is coated on the surface of the pretreated substrate and cured to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The coating film forming process parameters are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, and controlling the thickness of the polyimide layer at 10 um;

[0117] (3) Conductive grooves are opened on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, and the repetition frequency is 20 - 100 KHz. The conductive film is scanned and processed through a scanning galvanometer and an XY moving platform, controlling the grooving angle at 45° and the grooving depth at 0.11 um;

[0118] (4) Thermal conductive ink is sprayed and cured in the conductive grooves to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink consists of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, and 1 part of titanate coupling agent.

[0119] (5) Nano-silver conductive ink is filled into the conductive grooves sprayed with thermal conductive ink, dried and cured. The Ag content in the nano-silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0120] (6) The excess nano-silver conductive ink outside the V-shaped conductive grooves is removed to obtain the electrode pattern, and peeling is carried out by coating a release agent, controlling the peeling force at 20 - 25 grams;

[0121] (7) An ultraviolet curing liquid is coated and cured on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing liquid is 10%. The process parameters for coating and film formation are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, controlling the thickness of the transparent encapsulation layer at 150 nm.

[0122] Comparative Example 1

[0123] This comparative example includes most of the operation steps of Example 1, and the difference is that no thermal conductive protective layer is set. The specific preparation method is as follows:

[0124] (1) The substrate is corona pre-treated to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0125] (2) Polyimide slurry is coated and cured on the surface of the pre-treated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The process parameters for coating and film formation are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, controlling the thickness of the polyimide layer at 10 um;

[0126] (3) Open conductive grooves on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz. Scan and process the conductive film through a scanning galvanometer and an XY moving platform, control the grooving angle at 45°, and the grooving depth at 0.11 um;

[0127] (4) Fill the conductive grooves with nano - silver conductive ink, and dry and cure it. The Ag content in the nano - silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0128] (5) Remove the excess nano - silver conductive ink outside the V - shaped conductive grooves to obtain the electrode pattern, and peel it off by coating a release agent, controlling the peeling force at 20 - 25 grams;

[0129] (6) Coat and cure the ultraviolet - curable liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer. The solid content of the ultraviolet - curable liquid is 10%. The coating film - forming process parameters are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 um, and control the thickness of the transparent encapsulation layer at 150 nm.

[0130] Comparative Example 2

[0131] This comparative example includes most of the operation steps of Example 1, and the difference is that the thermal conductive protection layer is arranged between the conductive pattern and the encapsulation layer. The specific preparation method is as follows:

[0132] (1) Perform corona pretreatment on the substrate to control the surface dyne value of the substrate at 45 - 55 mN / m;

[0133] (2) Coat and cure the polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer. The solid content of the polyimide slurry is 20%. The coating film - forming process parameters are: pump flow rate 15 ml / s, coater speed 10 m / min, coating head gap 50 um, and control the thickness of the polyimide layer at 10 um;

[0134] (3) Open conductive grooves on the polyimide layer according to the electrode pattern design using a laser. The laser wavelength is 278 - 355 nm, the output power is 10 W, the pulse width is adjustable from 5 - 500 ns, the repetition frequency is 20 - 100 KHz. Scan and process the conductive film through a scanning galvanometer and an XY moving platform, control the grooving angle at 45°, and the grooving depth at 0.11 um;

[0135] (4) Fill the conductive grooves sprayed with thermal conductive ink with nano - silver conductive ink, and dry and cure it. The Ag content in the nano - silver conductive ink is 0.5%, the viscosity is 10 cps, and the drying temperature is 100 °C;

[0136] (5) Remove the redundant nano-silver conductive ink outside the V-shaped conductive groove to obtain an electrode pattern, and perform peeling by coating a release agent, controlling the peeling force at 20-25 grams;

[0137] (6) Spray and cure a thermal conductive ink on the surface of the polyimide coating after obtaining the electrode pattern to obtain a thermal conductive protective layer. The thickness of the thermal conductive protective layer is 7 nm. The thermal conductive ink is composed of the following components: 55 parts of polyimide resin, 25 parts of a mixed solvent of (γ-butyrolactone: propylene glycol monomethyl ether) with a mass ratio of 1:1, 1 part of triethylhexyl phosphate dispersant, 20 parts of boron nitride conductive filler, 1 part of titanate coupling agent, and 1 part of octadecylamine oxide modified additive.

[0138] (7) Coat and cure an ultraviolet curing solution on the surface of the thermal conductive protective layer to obtain a transparent encapsulation layer. The solid content of the ultraviolet curing solution is 10%. The coating film forming process parameters are: pump flow rate 10 ml / s, coater speed 15 m / min, coating head gap 100 μm, and control the thickness of the transparent encapsulation layer to be 150 nm.

[0139] Test Example

[0140] Perform performance tests on the electrodes prepared in Examples 1-10 and Comparative Example 1. The test items are as follows:

[0141] (1) Etching mark test: Use the human eye for testing. Judgment criterion: The human eye is 50 cm away from the device, based on whether the device pattern can be distinguished, and it is better if the etching line cannot be distinguished.

[0142] A: Can distinguish 50 μm and 30 μm etching lines.

[0143] B: Can distinguish 50 μm etching lines, but cannot distinguish 30 μm etching lines.

[0144] C: Cannot distinguish 50 μm and 30 μm etching lines

[0145] (2) Xenon lamp weather resistance test: Radiation intensity 0.8 W / m 2 , temperature 40 °C, humidity 55%, time 1000 h;

[0146] (3) Bending test: Bending angle 180°, bending radius R = 3 mm, number of times 300,000 times.

[0147] (4) Thermal conductivity test: Use the conductive film made of pre-patterned conductive grooves as the test device. The DC direct current energization times are 24 h, 48 h, and 72 h respectively. Use a handheld infrared thermometer to measure the surface temperature of the device at different time nodes.

[0148] The test results are shown in Tables 1-3.

[0149] Table 1

[0150]

[0151]

[0152] Table 2

[0153]

[0154] Table 3

[0155]

[0156]

[0157] Examples 1-3 are the transparent flexible thin film electrodes prepared by the present invention. From the above test results, it can be seen that by pre-burying conductive grooves, the present invention can control the cross-sectional shape of the electrodes, and the edges of the prepared electrode patterns are flat, the electrode etching marks are weak, the overall appearance is improved, the response speed of the prepared electrodes is 2-5 s, the number of times of bending resistance is more than 300,000 times, the temperature is 35-50 °C after heating for 72 h, the thermal conductivity is good, and the service life is greatly improved.

[0158] Examples 1 and Examples 4-7 are comparative experiments on conductive grooves. Among them, Examples 4-7 are studies on the grooving angle of conductive grooves. The grooving angle of conductive grooves will affect the compaction density of nano-silver conductive ink in the grooves, and then affect the lap situation of conductive lines. The grooving angles of Examples 4-5 are 0° and 80° respectively, and the etching marks are more serious, and the bending resistance performance is poor, manifested as cracks and whitening marks; Examples 6-7 are studies on the grooving depth of conductive grooves. The grooving depth of conductive grooves actually reflects the filling depth of conductive patterns. The grooving depths of Examples 6-7 are 0.02 um and 0.25 um respectively. If the grooving depth is too small, the filling amount of conductive materials is low, the touch response speed is slow, and the reaction is insensitive; if the grooving depth is too large, the etching marks are more serious, and the contact resistance becomes larger.

[0159] Examples 1, Examples 8-9 and Comparative Examples 1-2 are comparative experiments on thermal conductive protective layers. Among them, the thickness of the thermal conductive protective layer in Example 8 is 25 nm. If the thermal conductive protective layer is too thick, the contact resistance increases, the bending performance weakens, and micro-cracks appear; in Example 9, no modified additive is added to the thermal conductive ink of the thermal conductive protective layer, resulting in a decrease in the thermal conductivity of the thermal conductive ink and affecting the thermal conductivity of the electrodes; in Comparative Example 1, no thermal conductive protective layer is set, and the thermal conductivity of the electrodes is poor, and the temperature is 120 °C after heating for 72 h; in Comparative Example 2, the thermal conductive protective layer is set between the conductive pattern and the encapsulation layer. On the one hand, the amount of thermal conductive ink used increases, and at the same time the thickness of the electrodes increases. On the other hand, the contact resistance becomes larger, affecting the response speed and sensitivity of touch control.

[0160] In summary, the transparent flexible thin film electrode prepared by the method of the present invention has good thermal conductivity, fast response speed, good surface quality and long service life, and has good popularization and application value.

[0161] The above further describes the present invention with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.

Claims

1. A manufacturing method of a transparent flexible thin film electrode, characterized in that, It includes the following steps: (1) Pretreat the surface of the substrate; (2) Coat and cure a polyimide slurry on the surface of the pretreated substrate to obtain a polyimide layer; (3) Open conductive grooves on the polyimide layer according to the electrode pattern design. The conductive grooves are V-shaped conductive grooves, and the V-shaped conductive grooves are obtained by laser grooving. The grooving angle of the V-shaped conductive grooves is 30°-60°, and the grooving depth is 0.05-0.08 um; (4) Spray and cure a thermal conductive ink in the conductive grooves to obtain a thermal conductive protective layer with a thickness of 3-10 nm; (5) Fill the conductive grooves sprayed with the thermal conductive ink with a nano-silver conductive ink and dry and cure it; (6) Remove the excess nano-silver conductive ink outside the conductive grooves to obtain an electrode pattern; (7) Coat and cure an ultraviolet curing liquid on the surface of the polyimide coating after obtaining the electrode pattern to obtain a transparent encapsulation layer.

2. The manufacturing method of the transparent flexible thin film electrode according to claim 1, characterized in that In step (1), the surface dyne value of the pretreated substrate is controlled to be 40-60 mN / m, and in step (2), the thickness of the polyimide layer is 5-15 um.

3. The manufacturing method of the transparent flexible thin film electrode according to claim 1, characterized in that The thermal conductive ink consists of the following components: Matrix resin 50-65%; Dispersant 0.5-1.0%; Organic solvent 10-25%; Thermal conductive filler 10-25%; Coupling agent 0.5-1.0%; and, Modified additive 0.5-1.0%.

4. The manufacturing method of the transparent flexible thin film electrode according to claim 3, wherein The thermal conductive filler is selected from one of graphene, silicon carbide, boron nitride, silicon nitride, aluminum nitride, aluminum oxide, zinc oxide; the coupling agent is selected from one of silane coupling agent, titanate coupling agent, aluminate coupling agent, bimetallic coupling agent, phosphate coupling agent, borate coupling agent.

5. The manufacturing method of the transparent flexible thin film electrode according to claim 4, characterized in that, The modified additive is selected from at least one of octadecylamine, octadecylamine oxide, polydopamine, 1-pyrenebutyric acid, chlorosulfonic acid.

6. The manufacturing method of the transparent flexible thin film electrode according to claim 1, characterized in that In step (6), to remove the excess nano-silver conductive ink outside the conductive grooves, the specific steps are: coat a release agent on the cured nano-silver conductive ink to obtain a release layer, control the peel force of the release layer to be 10-30 grams, and then peel off the release layer to remove the excess nano-silver conductive ink to obtain an electrode pattern.

7. The manufacturing method of the transparent flexible thin film electrode according to claim 1, characterized in that In step (7), the thickness of the transparent encapsulation layer is 100-200 nm.

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