Flexible Touch Sensor and Touch Panel

Abstract

The present invention belongs to the technical field of flexible display screens, and provides a flexible touch sensor. By providing a flexible transparent substrate, which includes a flexible first electrode layer and a flexible second electrode layer containing a transferable transparent conductive film, the first electrode layer is transferred onto the flexible substrate, and the second electrode layer is transferred onto the first electrode layer, eliminating the traditional adhesive layer between the first electrode layer and the second electrode layer, effectively reducing the thickness of the touch sensor. At the same time, the substrate, the first electrode layer, and the second electrode layer all contain a transferable transparent conductive film with bend resistance, achieving the technical effect of being bendable. Additionally, since only the transferable transparent conductive film needs to be transferred onto the flexible transparent substrate and the first electrode layer, and then the patterning process can be completed through exposure and development, without the need for additional film coating and etching film removal steps, the process is simple and the yield is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible display screens, and particularly relates to a flexible touch sensor and a touch panel. Background Art

[0002] Due to advantages such as easy operation and flexibility, touch screens have become the main human-computer interaction means for personal mobile communication devices and integrated information terminals (such as mobile phones, tablet computers, and ultra-thin laptops, etc.). The relatively mature touch screen structures in the market are still 2D and 2.5D non-foldable touch screens such as GFF, OGS, On-Cell, and In-Cell. The emerging 3D touch screens with fixed-edge curved surfaces and foldable flexible touch screens have officially entered the mass production and rapid development stage, and the corresponding touch sensors are increasingly urgently required to be ultra-thin and bend-resistant. Currently, the double-layer film+film structure sensors in the flexible and fixed-edge curved surface 3D touch screen solutions have problems such as relatively thick thickness, poor bend resistance, or complex processes and low yield rates for the single-layer double-sided mesh (net-like) structure and single-layer bridging solutions. Summary of the Invention

[0003] The purpose of the present invention is to provide a flexible touch sensor and a touch panel, which are ultra-thin and bend-resistant, and have relatively simple processes and high yield rates.

[0004] To achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a flexible touch sensor, including a flexible transparent substrate, a flexible first electrode layer and a flexible second electrode layer containing a transferable transparent conductive film. The first electrode layer is transferred onto the flexible transparent substrate, the second electrode layer is transferred onto the first electrode layer, and a transparent adhesive layer is evenly coated on the second electrode layer for connecting with a cover plate; multiple signal lines are also provided on the flexible transparent substrate, and the signal lines are respectively connected to the first electrode layer and the second electrode layer to transmit the electrical signals of the first electrode layer and the second electrode layer to the FPC.

[0006] By providing a flexible transparent substrate, a flexible first electrode layer including a transferable transparent conductive film, and a flexible second electrode layer, transferring the first electrode layer onto the flexible substrate and the second electrode layer onto the first electrode layer, the conventional adhesive layer between the first electrode layer and the second electrode layer is eliminated, effectively reducing the thickness of the touch sensor. At the same time, the substrate, the first electrode layer, and the second electrode layer all include a bend-resistant transferable transparent conductive film, achieving the technical effect of bendability. In addition, since only the transferable transparent conductive film needs to be transferred onto the flexible transparent substrate and the first electrode layer, and then the patterning process can be completed through exposure and development, there is no need for additional film coating and etching film removal steps, and the process is simple with a high yield.

[0007] In the first possible implementation manner of the first aspect, the thickness of the flexible transparent substrate is greater than or equal to 10 μm and less than or equal to 100 μm.

[0008] The selection of the thickness of the flexible transparent substrate is a process obtained through multiple repeated experiments. Through experiments, when the thickness of the flexible transparent substrate is less than 10 μm, the bend-resistant performance of the transparent substrate is poor, it is easy to break, and the manufacturing process requirements are high with a low production yield; when the thickness of the flexible transparent substrate is greater than 100 μm, the bendable performance of the transparent substrate is poor, that is, it is not easy to bend, and it will cause the overall structure to be thicker; therefore, when the thickness of the flexible transparent substrate is greater than 10 μm and less than 100 μm, the substrate can have good flexibility and the transferable transparent conductive film can be smoothly transferred.

[0009] Combining the first aspect and the first possible implementation manner of the first aspect, in the second possible implementation manner of the first aspect, the thickness of the first electrode layer and the second electrode layer is greater than or equal to 2 μm and less than or equal to 8 μm.

[0010] The thickness of the first electrode layer and the second electrode layer is also an important factor affecting the final thickness of the touch sensor. Therefore, after multiple repeated experiments, the thickness in this implementation manner is selected. When the thickness of the first electrode layer and the second electrode layer is less than 2 μm, the bend-resistant performance of the two electrode layers is poor, it is easy to break, and the manufacturing process requirements are high with a low production yield; when the thickness of the first electrode layer and the second electrode layer is greater than 8 μm, the bendable performance of the two conductive layers is poor, that is, it is not easy to bend, and it will cause the overall structure to be thicker. Therefore, the thickness of the first electrode layer and the second electrode layer being greater than 2 μm and less than 8 μm is the key to achieving the invention purpose.

[0011] Combined with the first aspect and the second possible implementation manner of the first aspect, in the third possible implementation manner of the first aspect, the thickness of the flexible transparent substrate is greater than or equal to 15 μm and less than or equal to 50 μm, and the thicknesses of the first electrode layer and the second electrode layer are greater than or equal to 3 μm and less than or equal to 5 μm. With such settings, it can ensure that the subsequent assembled flexible touch sensor has good bending resistance and is not easily broken, and has low manufacturing process requirements and high production yield. Moreover, it can ensure that the flexible touch sensor has good bendability and is relatively easy to bend, and will not cause the overall structure to be too thick.

[0012] More optimized thickness values have an important impact on achieving the object of the present invention.

[0013] In the fourth possible implementation manner of the first aspect, the first electrode layer includes a first electrode pattern, the second electrode layer includes a second electrode pattern, the first electrode pattern and the second electrode pattern form a cross, the signal line includes a first signal line and a second signal line, the first signal line is electrically connected to the first electrode pattern, and the second signal line is electrically connected to the second electrode pattern.

[0014] The first electrode pattern and the second electrode pattern form a cross to form a coupling capacitance. When, for example, a human finger presses, a change in the coupling capacitance can be generated, and then the pressing position can be located to achieve a touch effect.

[0015] Combined with the first aspect and the fourth possible implementation manner of the first aspect, in the fifth possible implementation manner of the first aspect, the first electrode pattern and the second electrode pattern are patterns obtained by patterning the transferable transparent conductive film.

[0016] Obtaining electrode patterns by patterning the transferable transparent conductive film has a simple process, reduces the production steps in conventional products, and the yield of patterning the transferable conductive film is much higher than that of the complex process of the transparent conductive film (ITO).

[0017] Combined with the first aspect and the fourth possible implementation manner of the first aspect, in the sixth possible implementation manner of the first aspect, a plurality of first pins and a plurality of second pins are provided on the flexible transparent substrate, and the plurality of first pins and the plurality of second pins are arranged in a specified area of the flexible substrate for electrical connection with the FPC; a plurality of first electrode ports are provided at the edge of the first electrode pattern, and a plurality of second electrode ports are provided at the edge of the second electrode pattern. The first electrode ports are electrically connected to the first pins through the first signal line, and the second electrode ports are electrically connected to the second pins through the second signal line.

[0018] The first electrode pattern and the second electrode pattern are electrically connected to the first pin and the second pin through signal lines and are connected to the FPC. The FPC transmits the coupling capacitance signals generated in the first electrode pattern and the second electrode pattern, such as those generated by pressing of a human finger, to the PCB, achieving the effect of touch control.

[0019] Combined with the first aspect and the first to sixth possible implementation manners of the first aspect, in the seventh possible implementation manner of the first aspect, the transferable transparent conductive film includes nano metal wires or nano metal meshes.

[0020] The transferable transparent conductive film has the characteristics of being ultrathin and bend-resistant. The nano metal wires or nano metal meshes are small in size and invisible to the naked eye of a human, and are good materials for electrode patterns.

[0021] Combined with the first aspect and the first to sixth possible implementation manners of the first aspect, in the eighth possible implementation manner of the first aspect, the signal lines are silver lines obtained by printing photosensitive materials or by laser.

[0022] Due to the very small width of the signal lines themselves and the spacing between the signal lines, the silver lines obtained by printing or laser processes have better effects compared to other materials.

[0023] In a second aspect, the present invention further provides a touch panel, including a cover plate and the flexible touch sensor as described in the first aspect and the first to eighth possible implementation manners of the first aspect. The cover plate is a flexible plate or a curved surface glass and is connected to the flexible touch sensor through a transparent adhesive layer.

[0024] Connecting the flexible touch sensor to the cover plate can form a touch panel. This touch panel can be made into an integrated component, and electronic device manufacturers can directly purchase the touch panel. Additionally, since the cover plate is a flexible plate or a curved surface glass, it can be used to manufacture flexible display devices or curved surface glass devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 is an exploded schematic view of an embodiment;

[0027] Figure 2 is a cross-sectional structural schematic view of an embodiment;

[0028] Figure 3Schematic diagram of a partial position of the signal line connection in one implementation mode;

[0029] Figure 4 is Figure 3 partial enlarged schematic diagram;

[0030] Figure 5 Schematic diagram of a partial position of the signal line connection with the FPC in one implementation mode;

[0031] Figure 6 is Figure 5 partial enlarged schematic diagram;

[0032] Figure 7 Schematic diagram of the structure of an FPC in one implementation mode;

[0033] Figure 8 Schematic diagram of the cross-sectional structure of a touch panel in one implementation mode;

[0034] Figure 9 is Figure 8 schematic diagram of the touch panel structure in;

[0035] Figure 10 Schematic diagram of the cross-sectional structure of a touch panel in one implementation mode;

[0036] Figure 11 is Figure 10 schematic diagram of the touch panel structure in. Specific implementation mode

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] Please refer to Figure 1 and Figure 2 , Figure 1 is an exploded view of a flexible touch sensor provided by a preferred embodiment of the present invention, Figure 2It is a schematic cross-sectional structure diagram of the flexible sensor of the present invention. The flexible touch sensor includes a flexible transparent substrate 10, the material of which is a flexible insulating material, such as polymer materials like polyimide (PI), polycarbonate (PC), polyethersulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyaryl compound (PAR), or fiberglass reinforced plastic (FRP), etc., but not limited thereto. Preferably, it is polyimide (PI), especially colorless polyimide (CPI), which has good bending resistance and insulation properties.

[0039] The flexible first electrode layer 20 and the flexible second electrode layer 30 include a transparent conductive transfer film (transparent conductive transfer film, TCTF, not shown). The flexible first electrode layer 20 is transferred onto the flexible transparent substrate 10, and the flexible second electrode layer 30 is transferred onto the first electrode layer 20. A transparent adhesive layer 40 is evenly coated on the second electrode layer 30. The transparent adhesive layer 40 is used to connect with the cover plate (see Figure 8 the serial number 60 in Figure 10 or the serial number 70 in ). The first electrode layer 20 is, for example, a transmit electrode layer (generally abbreviated as the TX electrode), and the second electrode layer 30 is, for example, a receive electrode layer (generally abbreviated as the RX electrode). In one embodiment, the transfer method can be that the first electrode layer 20 is formed on the flexible transparent substrate 10 by a lamination process, and the second electrode layer 30 is formed on the first electrode layer 20 by a lamination process. In one embodiment, the transparent conductive transfer film includes nano metal wires or nano metal meshes.

[0040] The transparent adhesive layer 40 is an OCA solid transparent optical adhesive, an LOCA liquid transparent optical adhesive, or an OCR optical transparent resin. The present invention preferably uses an OCA solid transparent optical adhesive, and the thickness is preferably 25 - 50 μm.

[0041] Please refer to Figure 3 and Figure 4 , and multiple signal lines (101 / 102) are also provided on the flexible transparent substrate 10. The signal lines are electrically connected to the first electrode layer 20 and the second electrode layer 30 respectively to transmit the electrical signals of the first electrode layer 20 and the second electrode layer 30 to the FPC (see Figure 5 shown as 50 in ). In one embodiment, the signal lines are silver lines (Ag) obtained by printing photosensitive or laser. The material of the signal lines can also be gold (Au).

[0042] After multiple repeated tests, the thickness of the flexible transparent substrate 10 is greater than or equal to 10 μm and less than or equal to 100 μm, and the thicknesses of the first electrode layer 20 and the second electrode layer 30 are greater than or equal to 2 μm and less than or equal to 8 μm. In a preferred case, the thickness of the flexible transparent substrate is greater than or equal to 15 μm and less than or equal to 50 μm, and the thicknesses of the first electrode layer and the second electrode layer are greater than or equal to 3 μm and less than or equal to 5 μm. With such settings, it can ensure that the flexible touch sensor formed by subsequent assembly has good bending resistance, is not easily broken, has low manufacturing process requirements, high production yield, and at the same time, it will not make the flexible touch sensor have good bendability, is relatively easy to bend, and will not cause the overall structure to be too thick.

[0043] FPC is the abbreviation of Flexible Printed Circuit, which is a general technical term in the electronics industry. Please refer to Figure 7 , the structure of an FPC in one embodiment includes one end (5011 / 5021) with multiple connection contacts and one end 503 of an integrated plug. The multiple connection contacts (5011 / 5021) are used to connect to the signal line connectors of the touch sensor, and are generally divided into 3 regions. Please refer to 5 and Figure 6 , where the connection contacts 5021 in the middle region are connected to one type of signal line, and the connection contacts 5011 on both sides are connected to another type of connection contact. The 503 of the integrated plug is used to connect to the main board PCB (not shown) of the mobile phone. The FPC is usually in a zigzag shape and can be bent in one direction, which can convert the vertical wiring into horizontal wiring, facilitating the internal space layout of the electronic device.

[0044] Please refer to Figure 1 、 Figure 5 and Figure 6 , the first electrode layer 20 includes a first electrode pattern 201, and the second electrode layer 30 includes a second electrode pattern 301. The first electrode pattern 201 and the second electrode pattern 301 form an intersection. Generally, an intersection means that the first electrode pattern 201 and the second electrode pattern 301 are not parallel. For example, the included angle between the first electrode pattern 201 and the second electrode pattern 301 is 90°, or it can be other angles, etc., which will not be elaborated here. The purpose is to form a coupling capacitance between the first electrode pattern 201 and the second electrode pattern 301. In one embodiment, the first electrode pattern 201 and the second electrode pattern 301 are patterns obtained by patterning a transferable transparent conductive film. The patterning method can be that the first electrode pattern 201 is formed on the first electrode layer 20 through a chemical etching process, and the second electrode pattern 301 is formed on the second electrode layer 30 through a chemical etching process. From the foregoing embodiments, the first electrode pattern 201 and the second electrode pattern 301 can be nano metal wires or nano metal meshes.

[0045] Please refer toFigure 3 and Figure 4 The signal lines include a first signal line 101 and a second signal line 102. The first signal line 101 is electrically connected to the first electrode pattern 20, and the second signal line 102 is electrically connected to the second electrode pattern 30. It can be understood that in this embodiment, the first signal line 101 can also be electrically connected to the second electrode pattern 30, and the second signal line 301 can be electrically connected to the first electrode pattern 20. The first signal line 101 includes a first connection contact 1011 and a second connection contact 1012, and the second signal line 102 includes a third connection contact 1021 and a fourth connection contact 1022.

[0046] Please refer to Figure 4 , a plurality of first pins 1011 and a plurality of second pins 1021 are provided on the flexible transparent substrate 10. The plurality of first pins 1011 and the plurality of second pins 1021 are arranged in a specified area of the flexible substrate 10 for electrically connecting to the FPC 50; a plurality of first electrode ports (not shown) are provided at the edge of the first electrode pattern 201, and a plurality of second electrode ports (not shown) are provided at the edge of the second electrode pattern 301. The first electrode ports are connected to the first pins 1011 through the first signal line 101, and the second electrode ports are connected to the second pins 1021 through the second signal line 102; the first electrode ports are connected to the first joint 1012 of the first signal line, and the second electrode ports are connected to the second joint 1022 of the second signal line.

[0047] Please refer to Figure 8 and Figure 9 , an embodiment of the present invention also provides a touch panel, including a cover plate 60 and a flexible touch sensor. The cover plate 60 is a flexible plate and is connected to the flexible touch sensor through a transparent adhesive layer 40. The material of the flexible plate 60 can be polyimide (PI), especially colorless polyimide (CPI), which has good bending resistance and insulation properties. The touch panel of this embodiment can be widely applied in the flexible display industry, such as being made into flexible mobile phones, smart watches, etc.

[0048] Please refer to Figure 10 and Figure 11 , an embodiment of the present invention also provides a touch panel, which is different from the previous embodiment in that the cover plate 70 is a curved glass. The curved glass can be 2.5D curved or 3D curved glass. Since the flexible touch sensor has good bending resistance, it can fully meet the application on the curved glass. The application direction can be a mobile phone with a curved border display, etc.

[0049] The above-disclosed is only a preferred embodiment of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A flexible touch sensor, characterized in that, It includes a flexible transparent substrate, a flexible first electrode layer and a flexible second electrode layer including a transferable transparent conductive film. The first electrode layer is transferred onto the flexible transparent substrate, and the second electrode layer is transferred onto the first electrode layer. A transparent adhesive layer is evenly coated on the second electrode layer, and the transparent adhesive layer is used to connect to a cover plate. Multiple signal lines are also provided on the flexible transparent substrate, and the signal lines are respectively connected to the first electrode layer and the second electrode layer to transmit the electrical signals of the first electrode layer and the second electrode layer to the FPC. The thickness of the first electrode layer and the second electrode layer is greater than or equal to 2 μm and less than or equal to 8 μm. The signal lines are silver lines obtained by printing photosensitive or laser. The first electrode layer includes a first electrode pattern.

2. The flexible touch sensor according to claim 1, characterized in that, The thickness of the flexible transparent substrate is greater than or equal to 10 μm and less than or equal to 100 μm.

3. The flexible touch sensor according to claim 2, wherein The thickness of the flexible transparent substrate is greater than or equal to 15 μm and less than or equal to 50 μm, and the thickness of the first electrode layer and the second electrode layer is greater than or equal to 3 μm and less than or equal to 5 μm.

4. The flexible touch sensor according to claim 1, wherein The second electrode layer includes a second electrode pattern. The first electrode pattern and the second electrode pattern intersect. The signal lines include a first signal line and a second signal line. The first signal line is electrically connected to the first electrode pattern, and the second signal line is electrically connected to the second electrode pattern.

5. The flexible touch sensor according to claim 4, wherein, The first electrode pattern and the second electrode pattern are patterns obtained by patterning the transferable transparent conductive film.

6. The flexible touch sensor according to claim 4, wherein Multiple first pins and multiple second pins are provided on the flexible transparent substrate. The multiple first pins and the multiple second pins are arranged in a specified area of the flexible transparent substrate for electrical connection to the FPC. Multiple first electrode ports are provided at the edge of the first electrode pattern, and multiple second electrode ports are provided at the edge of the second electrode pattern. The first electrode ports are electrically connected to the first pins through the first signal line, and the second electrode ports are electrically connected to the second pins through the second signal line.

7. The flexible touch sensor according to any one of claims 1 to 6, characterized in that, The transferable transparent conductive film includes nano metal wires or nano metal meshes.

8. A touch panel, characterized in that, It includes a cover plate and the flexible touch sensor according to any one of claims 1 to 7. The cover plate is a flexible plate or a curved surface glass and is connected to the flexible touch sensor through a transparent adhesive layer.

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