Capacitive touch screen functional sheet, preparation method thereof, capacitive touch screen and electronic device

Abstract

The present invention discloses a capacitive touch screen functional sheet, comprising a substrate, a capacitive sensing layer, a capacitive sensing layer protective layer, a conductive electrode layer, a wear-resistant conductive layer, a shadow elimination protective layer and an OCA optical adhesive bonding layer, wherein the conductive electrode layer comprises a conductive electrode body and a conductive electrode lead extending outward from the conductive electrode body, and the capacitive sensing layer, the capacitive sensing layer protective layer, the shadow elimination protective layer and the OCA optical adhesive bonding layer are all transparent. The present invention also discloses a method for preparing a capacitive touch screen functional sheet, a capacitive touch screen and an electronic device. The capacitive touch screen functional sheet of the present invention has the advantages of good bending, low resistance, good conductivity, high light transmittance and simple structure.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitive touch screens, and in particular to a capacitive touch screen functional sheet, a method for preparing the capacitive touch screen functional sheet, a capacitive touch screen comprising the capacitive touch screen functional sheet, and an electronic device comprising the capacitive touch screen. Background Art

[0002] With the improvement of material life, consumers' requirements for electronic products are rapidly developing towards thinness, flexibility, visualization and touch control. At present, touch screens and related industrial chains are integrating into people's daily lives at a very fast speed all over the world. In addition, flexible display technology enables displays to be bent or curled into any shape, and is light, thin and easy to carry.

[0003] In the existing industry, hard inorganic oxide materials such as indium tin oxide (ITO) are mainly used as transparent capacitive sensing layers of touch screen functional sheets. Since indium tin oxide requires full-plate magnetron sputtering, the processing cost is high and the energy consumption is large. Graphicalization requires cumbersome process steps such as masking, exposure, development, etching, and washing. As a result, the downstream industry chain cannot realize the rapid manufacture of touch screens, which has brought many troubles and development bottlenecks to the electronics industry. For example, the Chinese invention patent with application number CN201510135151.2 uses ITO as a transparent capacitive sensing layer; for another example, the Chinese invention patent with application number CN201710122121.7 uses Ag and ITO to make capacitive touch screen functional sheets. It is mentioned that the functional sheets made of the mixed structure of Ag and ITO cannot be bent arbitrarily, and thus cannot be applied to flexible touch screens. In addition, due to the physical brittleness of the indium tin oxide layer, it is easily damaged during the manufacturing process, long-term use, and harsh environmental changes. Developing a capacitive touch screen functional sheet with simpler production process, lower production cost, better photoelectric transmittance and better bendability than the traditional indium tin oxide (ITO) transparent conductive layer has become an inevitable trend in future technological development. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, one of the purposes of the present invention is to provide a capacitive touch screen functional sheet to solve the problems that the existing capacitive touch screen functional sheet cannot be bent arbitrarily and is difficult to be applied to flexible touch screens. In addition, it can also overcome the problems of the existing capacitive touch screen functional sheet, such as complex production process, high production cost, poor light transmittance, high resistance, and low wear resistance.

[0005] The second object of the present invention is to provide a method for preparing a capacitive touch screen functional sheet, which has the advantages of simple preparation process, low production cost, good performance stability and high product yield of the prepared capacitive touch screen functional sheet.

[0006] A third object of the present invention is to provide a capacitive touch screen, which includes the above-mentioned capacitive touch screen functional sheet.

[0007] A fourth objective of the present invention is to provide an electronic device comprising the above-mentioned capacitive touch screen.

[0008] One of the purposes of the present invention is achieved by the following technical solution:

[0009] A capacitive touch screen functional sheet, comprising a substrate, a capacitive sensing layer, a capacitive sensing layer protective layer, a conductive electrode layer, a wear-resistant conductive layer, a shadow elimination protective layer and an OCA optical adhesive bonding layer, wherein the conductive electrode layer comprises a conductive electrode body and a conductive electrode lead extending outward from the conductive electrode body, and the capacitive sensing layer, the capacitive sensing layer protective layer, the shadow elimination protective layer and the OCA optical adhesive bonding layer are all transparent;

[0010] The capacitive sensing layer is arranged on the surface of the substrate, the capacitive sensing layer protective layer is arranged on the surface of the substrate and covers the capacitive sensing layer, the conductive electrode body is arranged on the capacitive sensing layer protective layer and is located at the outer edge of the capacitive sensing layer, the wear-resistant conductive layer covers the conductive electrode lead, the shadow elimination protective layer is arranged on the capacitive sensing layer protective layer and covers the conductive electrode body and the capacitive sensing layer protective layer, and the OCA optical adhesive layer is arranged on the shadow elimination protective layer and covers the shadow elimination protective layer;

[0011] The capacitive sensing layer is used to sense the capacitance change during touch and generate a positioning signal. The capacitive sensing layer transmits the positioning signal to the conductive electrode body, the conductive electrode lead and the wear-resistant conductive layer in sequence. The wear-resistant conductive layer transmits the positioning signal.

[0012] Furthermore, the substrate is a flexible substrate, and the thickness of the substrate is 12 to 2000 μm.

[0013] Furthermore, the capacitive sensing layer is a nano silver wire sensing circuit film layer, the square resistance of the capacitive sensing layer is ≤300Ω, and the thickness of the capacitive sensing layer is 35-2000nm.

[0014] Furthermore, the thickness of the capacitive sensing layer protection layer is 10-300 nm, and the square resistance of the capacitive sensing layer protection layer is ≤300Ω.

[0015] Furthermore, the square resistance of the conductive electrode layer is ≤1Ω, and the thickness of the conductive electrode layer is 200-20000nm.

[0016] Furthermore, the square resistance of the wear-resistant conductive layer is ≤20Ω, and the thickness of the wear-resistant conductive layer is 1-20 um.

[0017] Furthermore, the thickness of the shadow elimination protection layer is 30 to 5000 nm; the thickness of the OCA optical adhesive layer is 1 to 200 um.

[0018] The second object of the present invention is achieved by adopting the following technical solution:

[0019] A method for preparing a capacitive touch screen functional sheet, comprising:

[0020] Printing step: printing a first electrode layer, a capacitive sensing layer protection layer, a second electrode layer and a third electrode layer on a substrate in sequence by a printing method, wherein the second electrode layer includes a body layer and a lead layer extending outward from the body layer, the capacitive sensing layer protection layer covers the first electrode layer, the body layer and the lead layer are both arranged on the capacitive sensing layer protection layer, and the body layer is located at the outer edge of the first electrode layer, and the third electrode layer covers the lead layer, to obtain a printed board;

[0021] Etching step: etching a capacitive sensing layer on the first electrode layer, and etching the capacitive sensing layer protective layer on the capacitive sensing layer; etching the body layer to obtain a conductive electrode body, etching the lead layer to obtain a conductive electrode lead, and etching the first electrode layer under the conductive electrode body / conductive electrode lead, the capacitive sensing layer protective layer, and the third electrode layer on the conductive electrode lead;

[0022] The steps of making the shadow elimination protective layer are as follows: printing the shadow elimination protective layer on the capacitive sensing layer protective layer and the conductive electrode body by a printing method;

[0023] The steps for making the OCA optical adhesive bonding layer are as follows: coating the OCA optical adhesive on the shadow elimination protective layer by a coating method to form the OCA optical adhesive bonding layer.

[0024] Furthermore, the printing method is one or more of a gravure printing method, a flexographic printing method, a screen printing method, an offset printing method, a spray printing method and a embossing method, and the coating method is one of a roller coating method, a slit coating method, a micro-concave coating method and a wire rod coating method.

[0025] Furthermore, the etching is laser etching, and the width of the laser etching line is 1 to 500 um.

[0026] The third object of the present invention is achieved by adopting the following technical solution:

[0027] A capacitive touch screen comprises the capacitive touch screen functional sheet.

[0028] The fourth object of the present invention is achieved by adopting the following technical solution:

[0029] An electronic device comprises the above-mentioned capacitive touch screen.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The capacitive touch screen functional sheet of the present invention has excellent bending resistance, can be bent and twisted arbitrarily, and can be widely used in the field of flexible touch screen technology. Compared with the traditional ITO conductive layer, the capacitive touch screen functional sheet of the present invention has the advantages of low resistance, good conductivity, high light transmittance, simple structure, etc. At the same time, the unique structure of the capacitive touch screen functional sheet of the present invention can effectively protect the structure of each layer, and will not be damaged by friction during the preparation and use process.

[0032] (2) In the functional sheet of the capacitive touch screen of the present invention, the capacitive sensing layer is a transparent conductive layer with high light transmittance; the conductive electrode layer is used as a conductive lead to reduce the overall loop resistance; the wear-resistant conductive layer is printed on the conductive electrode lead to protect the conductive electrode lead from being scratched when it contacts the circuit board; the capacitive sensing layer protective layer provides a protective layer with a hardness of more than 1H for the capacitive sensing layer, and after printing the capacitive sensing layer, a capacitive sensing layer protective layer of a certain thickness is printed, so that the capacitive sensing layer is connected to the conductive electrode layer through the capacitive sensing layer protective layer. The shadow-eliminating protective layer is used to fill the gap between the image and the non-image part, thereby reducing the visual contrast of the human eye, and providing a protective layer with a hardness of more than 1H. The OCA optical adhesive bonding layer is used to bond the functional sheet to the panel of the touch screen, and the OCA optical adhesive has the characteristics of being colorless and transparent, with a light transmittance of more than 90%, and good bonding strength.

[0033] (3) A capacitive touch screen and an electronic device of the present invention include the above-mentioned capacitive touch screen functional sheet, which has all the advantages of the above-mentioned capacitive touch screen functional sheet, and has the characteristics of low resistance, good conductivity, low production cost and excellent bendability, etc., meets the requirements of a flexible touch screen, and can be bent and twisted at will. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a capacitive touch screen functional sheet according to an embodiment of the present invention;

[0035] Figure 2 for Figure 1 A partial enlarged cross-sectional view of a conductive electrode body in a capacitive touch screen functional sheet shown;

[0036] Figure 3 for Figure 1 A cross-sectional view of a conductive electrode body in a capacitive touch screen functional sheet shown;

[0037] Figure 4 for Figure 1 A local enlarged cross-sectional view of the conductive electrode leads in the capacitive touch screen functional sheet is shown.

[0038] In the figure: 10, substrate; 20, capacitive sensing layer; 30, capacitive sensing layer protection layer; 40, conductive electrode layer; 41, conductive electrode body; 42, conductive electrode lead; 50, wear-resistant conductive layer; 60, shadow elimination protection layer; 70, OCA optical adhesive layer. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0040] Figure 1 The figure is a schematic structural diagram of a capacitive touch screen functional sheet according to an embodiment of the present invention.

[0041] like Figure 1-4 As shown, an electronic device with a capacitive touch screen, for example, can be a smart phone, a smart TV or a tablet computer, wherein the capacitive touch screen functional sheet in the capacitive touch screen includes a substrate 10, a transparent capacitive sensing layer 20, a transparent capacitive sensing layer protective layer 30, a conductive electrode layer 40, a wear-resistant conductive layer 50, a transparent shadow elimination protective layer 60 and a transparent OCA optical adhesive layer 70. Among them, the conductive electrode layer 40 includes a conductive electrode body 41 and a conductive electrode lead 42 extending outward from the conductive electrode body 41. The capacitive sensing layer 20 is arranged in the middle of the upper surface of the substrate 10 (the area of ​​the upper surface of the substrate 10 is larger than the area of ​​the upper surface of the capacitive sensing layer 20), the capacitive sensing layer protective layer 30 is also arranged on the upper surface of the substrate 10 and covers the capacitive sensing layer 20, and the conductive electrode body 41 is arranged on the upper surface of the capacitive sensing layer protective layer 30 and is located at the outer edge of the capacitive sensing layer 20 (i.e., as shown in FIG. 1 ). Figure 3As shown, the conductive electrode body 41 is arranged on the upper surface of the capacitive sensing layer protective layer 30, and the conductive electrode body 41 is laid at the outer edge of the capacitive sensing layer 20. At this time, the interior of the conductive electrode body 41 is a transparent capacitive sensing area, and the area covered by the conductive electrode body 41 and the area outside it are the positioning signal conduction area. The conductive electrode lead 42 extends outward from the conductive electrode body 41 to conduct the positioning signal. The wear-resistant conductive layer 50 covers the conductive electrode lead 42. The shadow elimination protective layer 60 is arranged on the upper surface of the capacitive sensing layer protective layer 30 and covers the conductive electrode body 41 (corresponding to the positioning signal conduction area) and the capacitive sensing layer protective layer 30 (corresponding to the capacitive sensing area). The OCA optical adhesive layer 70 is arranged on the shadow elimination protective layer 60 and covers the shadow elimination protective layer 60 (it can also cover the entire upper surface of the substrate 10). When using the capacitive touch screen, the capacitive touch screen is slid by the finger, so that the capacitive sensing layer 20 on the capacitive touch screen functional sheet is connected to the earth through the human body, that is, the alternating current signal excited by the capacitive screen itself is transmitted to the capacitive sensing layer 20, and further connected to the earth through the human body capacitance, thereby changing the frequency or peak of the original excitation signal to form a coupled positioning signal, and the capacitive sensing layer 20 transmits the positioning signal to the conductive electrode body 41, the conductive electrode lead 42 and the wear-resistant conductive layer 50 in sequence, and finally, the wear-resistant conductive layer 50 transmits the positioning signal to the electronic device itself or an external central processor, thereby calculating the position of the positioning signal (that is, the position where the finger touches the capacitive touch screen). At the same time, since the capacitive sensing layer 20, the capacitive sensing layer protective layer 30, the shadow elimination protective layer 60 and the OCA optical adhesive layer 70 are all transparent, the capacitive touch screen has a strong light transmittance and does not affect the overall brightness of the touch screen.

[0042] As a preferred embodiment, the substrate 10 is preferably a flexible substrate, for example, a polyester substrate, including one of a polyethylene terephthalate (PET) substrate, a polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG) substrate and a dicarboxylate substrate. Usually the polyester substrate (especially the PET substrate) can also be hardened by applying a coating on one side or both sides to meet the mechanical performance requirements in the production process. Preferably, a double-sided hardened PET film is selected as the substrate 10. The substrate 10 can also be a polyethylene substrate, such as a polyvinyl chloride substrate, a polyvinylidene chloride substrate, a polyvinyl butyral substrate, a polystyrene substrate and a polyacrylate substrate. The substrate 10 can also be one of a polyimide film, a polysulfone film and a silicone film. The hardness of the substrate is above 1H, and its light transmittance reaches 92%, and the haze is 0.4%.

[0043] As a preferred embodiment, the thickness of the substrate 10 is preferably 12 to 2000 μm, more preferably 50 to 200 μm.

[0044] As a preferred embodiment, the capacitive sensing layer 20 is a nano silver wire sensing circuit film layer, the square resistance of the capacitive sensing layer 20 is ≤300Ω, and the thickness of the capacitive sensing layer 20 is 35-2000nm.

[0045] As a preferred embodiment, the thickness of the capacitive sensing layer protective layer 30 is 10 to 300 nm, so as to provide a protective layer with a hardness of more than 1H, and protect the capacitive sensing layer protective layer 30 from being damaged in the subsequent printing process, and the square resistance of the capacitive sensing layer protective layer 30 is ≤300Ω. As a preferred embodiment, the capacitive sensing layer protective layer 30 can be a heat-curable or UV-curable protective thin layer, and the heat-curable or UV-curable protective thin layer is prepared by dissolving one or more of cellulose derivatives, epoxy resins, epoxy acrylic resins, alkyd resins, amino resins, polyester resins, phenolic resins, chloroacetic resins, polyamide resins, chlorinated polypropylene resins, polyurethane-modified acrylic resins, polyurethane resins, styrene maleic acid resins, melamine resins, pine ester resins, silicone resins, and silica sols in a solvent.

[0046] As a preferred embodiment, the square resistance of the conductive electrode layer 40 is ≤1Ω, and the thickness of the conductive electrode layer 40 is 200-20000nm. More preferably, the conductive electrode layer 40 is a non-transparent conductive electrode, and its square resistance is ≤0.5Ω. The conductive electrode layer 40 is printed with a first conductive ink to reduce the overall loop resistance of the capacitive touch screen functional sheet. The first conductive ink is prepared from at least one of nano silver particles, nano copper particles, graphene, micron silver powder, silver copper powder, aluminum powder and nickel powder, and the viscosity of the first conductive ink is between 5 and 50000Mpa.s, and more preferably between 50 and 500Mpa.s.

[0047] As a preferred embodiment, the wear-resistant conductive layer 50 is a non-transparent conductive electrode, the square resistance of the wear-resistant conductive layer 50 is ≤20Ω, more preferably, the square resistance of the wear-resistant conductive layer 50 is ≤10Ω, and the thickness of the wear-resistant conductive layer 50 is 1-20um. The wear-resistant conductive layer 50 is used to protect the contact part of the conductive electrode lead 42 and the FPC (flexible circuit board) from being scratched. In a specific embodiment, the wear-resistant conductive layer 50 is made of a second conductive ink, and the second conductive ink is a conductive paste prepared by at least one of conductive fillers such as graphite, graphene, carbon black, conductive titanium dioxide, nanosilver particles, nanocopper particles, silver copper powder, micron silver powder, aluminum powder and nickel powder.

[0048] As a preferred embodiment, the thickness of the transparent shadow-eliminating protective layer 60 is 30 to 5000 nm. The shadow-eliminating protective layer 60 covers the capacitive sensing layer protective layer 30 and the conductive electrode body 41, and is used to fill the gap between the conductive area and the non-conductive area formed after etching, thereby further reducing the visual contrast of the human eye, and providing a protective layer with a hardness of more than 1H. The shadow-eliminating protective layer 60 is a flowing liquid, which is prepared by dissolving at least one of cellulose derivatives, epoxy resins, epoxy acrylic resins, alkyd resins, amino resins, polyester resins, phenolic resins, chloroacetic resins, polyamide resins, chlorinated polypropylene resins, polyurethane modified acrylic resins, polyurethane resins, styrene maleic acid resins, melamine resins, pine ester resins, silicone resins and silica sols in a solvent.

[0049] As a preferred embodiment, the transparent OCA optical adhesive layer 70 has a thickness of 1 to 200 um and is used to adhere the functional sheet to the touch panel. It has the advantages of being colorless and transparent, having a light transmittance of more than 90%, having good bonding strength, being curable at room temperature or medium temperature, and being UV curable. The transparent OCA optical adhesive layer 70 is an optically transparent polymer made of at least one of acrylic resin, unsaturated polyester, epoxy resin, polyurethane-acrylic resin, silicone resin, and fluorine-containing polymer.

[0050] The following is a detailed description of the method for preparing the capacitive touch screen functional sheet of the present invention using Examples 1-4.

[0051] Example 1

[0052] Printing step: By gravure printing, a 30nm thick nano silver wire film layer, a 10nm thick epoxy acrylic resin protective layer, a 200nm thick nano silver particle conductive ink and a 1μm thick graphene conductive ink are sequentially printed on a 12μm thick PET substrate (in this embodiment, the PET substrate is subjected to double-sided coating hardening treatment to make the hardness of the printed surface 1H and the hardness of the non-printed surface 3H) roll-to-roll. Each printed layer needs to be dried and cured before the next printing step. The nano silver particle conductive ink includes a body layer and a lead layer extending outward from the body layer, the epoxy acrylic resin protective layer covers the nano silver film layer, the body layer and the lead layer are both arranged on the epoxy acrylic resin protective layer, and the body layer is located at the outer edge of the nano silver wire film layer, and the graphene conductive ink covers the lead layer to obtain a printed board.

[0053] Etching step: yellow light is used to etch the capacitive sensing layer 20 on the nano silver wire film layer, and yellow light is used to etch (the optical path width of yellow light is 100um) the epoxy acrylic resin protective layer on the nano silver wire film layer, thereby preparing the capacitive sensing circuit film layer of the circuit sensing area. Yellow light is used to etch the body layer to obtain the conductive electrode body 41, and yellow light is used to etch the lead layer to obtain the conductive electrode lead 42. At the same time, yellow light is used to etch the nano silver wire film layer, epoxy acrylic resin protective layer and graphene conductive ink on the conductive electrode lead 42 under the conductive electrode body 41 / conductive electrode lead 42.

[0054] Steps for making the shadow-eliminating protective layer: On the epoxy acrylic resin protective layer and the conductive electrode body 41, a flowing liquid is printed by a flexographic printing method to form a 30nm thick shadow-eliminating protective layer 60, and the flowing liquid is made of epoxy resin.

[0055] Steps for making an OCA optical adhesive layer: On the shadow-eliminating protective layer 60, apply OCA optical adhesive by roller coating to form a 1 μm thick OCA optical adhesive layer 70 (the OCA optical adhesive layer 70 may also cover the entire upper surface of the substrate 10). The OCA optical adhesive is made of polyurethane-acrylic resin, thereby obtaining a capacitive touch screen functional sheet.

[0056] Example 2

[0057] Printing steps: By silk-screen printing, a 2000nm thick nano silver wire film layer, a 300nm thick alkyd resin protective layer, a 20000nm thick graphene conductive ink and a 20μm thick silver copper powder conductive ink are sequentially printed roll-to-roll on a 2000μm thick polyvinyl chloride substrate (in this embodiment, the non-printing surface is subjected to a single-sided coating hardening treatment to make its hardness 3H). Each printed layer needs to be dried and cured before the next step of printing can be performed. The graphene conductive ink includes a body layer and a lead layer extending outward from the body layer, the alkyd resin protective layer covers the nano silver film layer, the body layer and the lead layer are both arranged on the alkyd resin protective layer, and the body layer is located at the outer edge of the nano silver wire film layer, and the silver copper powder conductive ink covers the lead layer to obtain a printed board.

[0058] Etching step: laser etching the capacitive sensing layer 20 on the nano silver wire film layer, and laser etching (laser optical path width 1um) the alkyd resin protective layer on the nano silver wire film layer, thereby preparing the capacitive sensing circuit film layer of the circuit sensing area. Laser etching the body layer to obtain the conductive electrode body 41, laser etching the lead layer to obtain the conductive electrode lead 42, and laser etching the nano silver film layer under the conductive electrode body 41 / conductive electrode lead 42, the alkyd resin protective layer, and the silver copper powder conductive ink on the conductive electrode lead 42.

[0059] Steps for making the shadow-eliminating protective layer: On the alkyd resin protective layer and the conductive electrode body 41, a flowing liquid is printed by offset printing to form a 5000nm thick shadow-eliminating protective layer 60, and the flowing liquid is made of polyamide resin, chlorinated polypropylene resin and polyurethane modified acrylic resin.

[0060] Steps for making an OCA optical adhesive layer: On the shadow-eliminating protective layer 60, apply OCA optical adhesive by a wire rod coating method to form a 200 μm thick OCA optical adhesive layer 70 (the OCA optical adhesive layer 70 may also cover the entire upper surface of the substrate 10). The OCA optical adhesive is made of a silicone resin, thereby obtaining a capacitive touch screen functional sheet.

[0061] Example 3

[0062] Printing steps: By using a jet printing method, a 80nm thick nano silver wire film layer, a 100nm thick phenolic resin protective layer, a 5000nm thick silver powder-copper powder conductive ink and a 5μm thick nano titanium dioxide particle conductive ink are sequentially printed roll-to-roll on a 50μm thick polyimide substrate. Each printed layer needs to be dried and cured before the next printing step. The silver powder-copper powder conductive ink includes a body layer and a lead layer extending outward from the body layer. The phenolic resin protective layer covers the nano silver wire film layer. The body layer and the lead layer are both arranged on the phenolic resin protective layer, and the body layer is located at the outer edge of the nano silver wire film layer. The nano titanium dioxide particle conductive ink covers the lead layer to obtain a printed board.

[0063] Etching step: laser etching the capacitive sensing layer 20 on the nano silver wire film layer, and laser etching (laser optical path width 500um) the phenolic resin protective layer on the nano silver wire film layer, thereby preparing the capacitive sensing circuit film layer of the circuit sensing area. Laser etching the body layer to obtain the conductive electrode body 41, laser etching the lead layer to obtain the conductive electrode lead 42, and laser etching the nano silver wire film layer under the conductive electrode body 41 / conductive electrode lead 42, the phenolic resin protective layer, and the nano titanium dioxide particle conductive ink on the conductive electrode lead 42.

[0064] Steps for making the shadow-eliminating protective layer: On the phenolic resin protective layer and the conductive electrode body 41, a flowing liquid is printed by a stamping method to form a 200nm thick shadow-eliminating protective layer 60, and the flowing liquid is made of melamine resin, pine ester resin and silicone resin.

[0065] Steps for making an OCA optical adhesive layer: On the shadow-eliminating protective layer 60, OCA optical adhesive is coated by a micro-concave coating method to form a 500 μm thick OCA optical adhesive layer 70 (the OCA optical adhesive layer 70 may also cover the entire upper surface of the substrate 10). The OCA optical adhesive is made of polyurethane-acrylic resin, thereby obtaining a capacitive touch screen functional sheet.

[0066] Example 4

[0067] Printing steps: By gravure printing, a 800nm ​​thick nano silver wire film layer, a 200nm thick pine ester resin protective layer, a 15000nm thick nickel powder-aluminum powder conductive ink and a 15μm thick graphite-carbon black-micron silver powder conductive ink are printed on a 1000μm thick silicone substrate in turn by roll-to-roll printing. Each printed layer needs to be dried and cured before the next printing step. The nickel powder-aluminum powder conductive ink includes a body layer and a lead layer extending outward from the body layer. The pine ester resin protective layer covers the nano silver wire film layer. The body layer and the lead layer are both arranged on the pine ester resin protective layer, and the body layer is located at the outer edge of the nano silver wire film layer. The graphite-carbon black-micron silver powder conductive ink covers the lead layer to obtain a printed board.

[0068] Etching step: laser etching the capacitive sensing layer 20 on the nano silver wire film layer, and laser etching (laser optical path width 200um) the high pine ester resin protective layer on the nano silver wire film layer, thereby preparing the capacitive sensing circuit film layer of the circuit sensing area. Laser etching the body layer to obtain the conductive electrode body 41, laser etching the lead layer to obtain the conductive electrode lead 42, and laser etching the nano silver wire film layer under the conductive electrode body 41 / conductive electrode lead 42, the high pine ester resin protective layer, and the graphite-carbon black-micron silver powder conductive ink on the conductive electrode lead 42.

[0069] Steps for making the shadow-eliminating protective layer: On the pine ester resin protective layer and the conductive electrode body 41, a flowing liquid is printed by a stamping method to form a 1000nm thick shadow-eliminating protective layer 60, and the flowing liquid is made of polyurethane modified acrylic resin, polyurethane resin and styrene maleic acid resin.

[0070] Steps for making an OCA optical adhesive layer: On the shadow-eliminating protective layer 60, apply OCA optical adhesive by a slit coating method to form a 1000 μm thick OCA optical adhesive layer 70 (the OCA optical adhesive layer 70 may also cover the entire upper surface of the substrate 10), wherein the OCA optical adhesive is made of a fluorine-containing polymer, thereby obtaining a capacitive touch screen functional sheet.

[0071] The capacitive touch screen functional sheets prepared in Examples 1-4 were used for the following performance tests, and the test results are shown in Table 1:

[0072] (1) Surface hardness test:

[0073] Use a pencil with a hardness of 1H to scratch the surface of the capacitive touch screen functional sheet in Examples 1-4, with a length of not less than 10 cm and 10 times. After scratching, wipe off the stain with a damp cloth and observe the surface of the capacitive touch screen functional sheet with the naked eye to see if there are any scratches.

[0074] (2) Impact resistance test:

[0075] The capacitive touch screen functional sheet in Example 1-4 was placed on a table, and a steel ball weighing 67.5 g and having a diameter of 25.4 mm was dropped freely from a height of 40 cm, with the landing points being no less than 5. After the striking, the surface of the capacitive touch screen functional sheet was observed with the naked eye to see if there were any cracks.

[0076] (3) Light transmittance test

[0077] Play a 100% pure white picture on the projector, and use a color analyzer to measure the brightness value at the center of the display screen, which is calculated as A, in units of nit. Install the capacitive touch screen functional sheet of Example 1-4 at the light exit hole of the projector, so that white light passes through the capacitive sensing area, and use a color analyzer to measure the brightness value at the center of the display screen, which is calculated as B, in units of nit. Calculate the transmittance according to the formula: transmittance = B / A*100%.

[0078] (4) Bendability test

[0079] The capacitive touch screen functional sheet in Examples 1-4 was tested using a swing tester. One end of the sheet was fixed and the other end was clamped with a swing clamp. The bending angle of the sheet was set to ±60°. The sheet was bent at a speed of 20 to 30 times per minute for 5 minutes. After the test, the capacitive touch screen functional sheet was observed for damage.

[0080] The capacitive touch screen functional sheets prepared in Examples 1-4 were further assembled into an electronic device with a capacitive touch screen according to the present invention by conventional methods. The four electronic devices were tested as follows. The test results are shown in Table 1:

[0081] (1) Anti-interference test:

[0082] a) Lay the machine flat on the table, open the pointer location test tool, drop 5 ml of water on the touch screen, leave it there for 10 seconds, wipe off the water, and the touch screen should show no abnormal performance;

[0083] b) Open the pointer location test tool, hold down the touch screen with one finger, and the display screen will show a static crosshair. Slide another finger horizontally or vertically on the touch screen to slowly move closer to the static crosshair, and finally merge the sliding crosshair and the static crosshair into one line on the X-axis or Y-axis. During the process of moving closer, the static crosshair cannot shake violently, and the displacement generated is less than 3mm.

[0084] (2) Sensitivity test:

[0085] It should be able to sense 3M's MHP-1000S capacitive stylus.

[0086] Test method: Use the MHP-1000S capacitive pen to draw and write normally. The drawn lines and written words are not allowed to be broken. The sensing sensitivity is judged based on normal drawing and writing conditions.

[0087] Table 1

[0088] Example 1 Example 2 Example 3 Example 4 Surface hardness test No scratches No scratches No scratches No scratches Impact resistance test No cracks No cracks No cracks No cracks Light transmittance (%) 92 95 97 96 Bending test No damage No damage No damage No damage Anti-interference test No interference No interference No interference No interference Sensitivity test Sensitive Sensitive Sensitive Sensitive

[0089] The above test results show that the capacitive touch screen functional sheets in Examples 1-4 have good wear resistance and impact resistance, high light transmittance, can be bent and twisted arbitrarily, and can be widely used in the field of flexible touch screen technology. The electronic device with a capacitive touch screen assembled from the capacitive touch screen functional sheets in Examples 1-4 has the characteristics of high sensitivity when touched, strong anti-interference performance and excellent conductivity.

[0090] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A capacitive touch screen functional sheet, characterized in that: It includes a substrate, a capacitive sensing layer, a capacitive sensing layer protective layer, a conductive electrode layer, a wear-resistant conductive layer, a shadow elimination protective layer and an OCA optical adhesive bonding layer, wherein the conductive electrode layer includes a conductive electrode body and a conductive electrode lead extending outward from the conductive electrode body, and the capacitive sensing layer, the capacitive sensing layer protective layer, the shadow elimination protective layer and the OCA optical adhesive bonding layer are all transparent; The capacitive sensing layer is arranged on the surface of the substrate, the capacitive sensing layer protective layer is arranged on the surface of the substrate and covers the capacitive sensing layer, the conductive electrode body is arranged on the capacitive sensing layer protective layer and is located at the outer edge of the capacitive sensing layer, the wear-resistant conductive layer covers the conductive electrode lead, the shadow elimination protective layer is arranged on the capacitive sensing layer protective layer and covers the conductive electrode body and the capacitive sensing layer protective layer, and the OCA optical adhesive layer is arranged on the shadow elimination protective layer and covers the shadow elimination protective layer; The capacitive sensing layer is used to sense the capacitance change during touch and generate a positioning signal. The capacitive sensing layer transmits the positioning signal to the conductive electrode body, the conductive electrode lead and the wear-resistant conductive layer in sequence. The wear-resistant conductive layer transmits the positioning signal.

2. The capacitive touch screen functional sheet according to claim 1, characterized in that: The substrate is a flexible substrate, and the thickness of the substrate is 12-2000 μm.

3. The capacitive touch screen functional sheet according to claim 1, characterized in that: The capacitive sensing layer is a nano silver wire sensing circuit film layer, the square resistance of the capacitive sensing layer is ≤300Ω, and the thickness of the capacitive sensing layer is 35-2000nm.

4. The capacitive touch screen functional sheet according to claim 1, characterized in that: The thickness of the capacitive sensing layer protection layer is 10-300 nm, and the square resistance of the capacitive sensing layer protection layer is ≤300Ω.

5. The capacitive touch screen functional sheet according to claim 1, characterized in that: The square resistance of the conductive electrode layer is ≤1Ω, and the thickness of the conductive electrode layer is 200-20000nm.

6. The capacitive touch screen functional sheet according to claim 1, characterized in that: The square resistance of the wear-resistant conductive layer is ≤20Ω, and the thickness of the wear-resistant conductive layer is 1-20um.

7. The capacitive touch screen functional sheet according to claim 1, characterized in that: The thickness of the shadow elimination protection layer is 30 to 5000 nm; the thickness of the OCA optical adhesive layer is 1 to 200 um.

8. A method for preparing a capacitive touch screen functional sheet according to any one of claims 1 to 7, characterized in that: include: Printing step: printing a first electrode layer, a capacitive sensing layer protection layer, a second electrode layer and a third electrode layer on a substrate in sequence by a printing method, wherein the second electrode layer includes a body layer and a lead layer extending outward from the body layer, the capacitive sensing layer protection layer covers the first electrode layer, the body layer and the lead layer are both arranged on the capacitive sensing layer protection layer, and the body layer is located at the outer edge of the first electrode layer, and the third electrode layer covers the lead layer, to obtain a printed board; Etching step: etching a capacitive sensing layer on the first electrode layer, and etching a capacitive sensing layer protection layer on the capacitive sensing layer; Etching the body layer to obtain a conductive electrode body, etching the lead layer to obtain a conductive electrode lead, and simultaneously etching the first electrode layer under the conductive electrode body / conductive electrode lead, the capacitive sensing layer protection layer, and the third electrode layer on the conductive electrode lead; The steps of making the shadow elimination protective layer are as follows: printing the shadow elimination protective layer on the capacitive sensing layer protective layer and the conductive electrode body by a printing method; The steps for making the OCA optical adhesive bonding layer are as follows: coating the OCA optical adhesive on the shadow elimination protective layer by a coating method to form the OCA optical adhesive bonding layer.

9. A capacitive touch screen, characterized in that: The capacitive touch screen comprises the capacitive touch screen functional sheet according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The electronic device comprises the capacitive touch screen according to claim 9.

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