Metal mesh three-dimensional touch screen and preparation method thereof

Abstract

This invention relates to the field of touch screen technology, providing a metal mesh three-dimensional touch screen and its fabrication method. The metal mesh three-dimensional touch screen includes several first metal mesh layers and several second metal mesh layers, all connected to an isolation layer. Each first metal mesh layer includes several first metal strips, and each second metal mesh layer includes several second metal strips. Both the first and second metal mesh layers are connected to a signal processing device. The first metal mesh layers are used to measure capacitance changes to obtain two-dimensional planar coordinates, and the second metal mesh layers are used to measure resistance changes to obtain three-dimensional pressure values. The projections of the first and second metal strips onto the isolation layer intersect each other. By adopting this structure, the three-dimensional touch accuracy is improved, the measurement structures are difficult to decouple, and the advantages of a thin and light size are also achieved.

Description

Technical Field

[0001] This invention relates to the field of touch screen technology, and in particular to a three-dimensional touch screen with a metal mesh and its preparation method. Background Technology

[0002] Touchscreens are intuitive and easy to operate, and have become a widely used medium for human-computer interaction in smart devices. With the development of touchscreen technology, the existing touchscreens have matured the two-dimensional coordinate recognition function of touch position. However, the three-dimensional touch function that introduces pressure sensing requires the addition of an additional pressure sensor, which will greatly increase the structural complexity and overall size of the touchscreen.

[0003] A simplified approach to pressure sensors is to integrate pressure sensing and coordinate sensing functions into a double-layer metal mesh structure. A deformable material is placed between the two layers of metal mesh. When the touch is pressed, the pressure value is obtained by the capacitance change caused by the change in distance between the two layers of metal mesh.

[0004] In existing technologies, pressure and two-dimensional coordinate sensing are achieved using mutual or self-capacitance methods. When measuring pressure, it is difficult to decouple the two metal mesh layers. The accuracy of pressure measurement is limited by the upper metal mesh and the deformation material in the middle layer. When the material has attenuation or springback issues, it has a significant negative impact on the accuracy of pressure measurement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a metal mesh three-dimensional touch screen and its fabrication method. This invention seeks to solve the technical problems of insufficient three-dimensional touch accuracy and difficulty in decoupling measurement structures in existing technologies.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A three-dimensional touchscreen with a metal mesh includes several first metal mesh layers and several second metal mesh layers. Each of the first metal mesh layers is connected to an isolation layer. The side of the isolation layer facing away from the first metal mesh layers is connected to the several second metal mesh layers. Each first metal mesh layer includes several first metal strips, which are interconnected to form several first closed metal rings. The first metal strips are also connected to form several first partitions, which are located within the first closed metal rings and spaced apart from them. Each second metal mesh layer includes several second metal strips, which are interconnected to form several second closed metal rings. The second metal strips are also connected to several second partitions, which are located within the second closed metal rings and spaced apart from them. Both the first and second metal mesh layers are connected to a signal processing device. The first metal mesh layers are used to measure capacitance changes to obtain two-dimensional planar coordinates, and the second metal mesh layers are used to measure resistance changes to obtain three-dimensional pressure values. The projections of the first metal strips onto the isolation layer and the projections of the second metal strips onto the isolation layer intersect each other.

[0007] Furthermore, the width of the first metal strip is 2.3μm to 4.3μm, and the width of the second metal strip is 3μm to 5μm.

[0008] Furthermore, the first metal mesh layer and the second metal mesh layer are positioned correspondingly, and the first metal mesh layer and the corresponding second metal mesh layer form a sensing area. The projection of the first metal mesh layer onto the isolation layer and the projection of the second metal mesh layer onto the isolation layer form a rhombus array.

[0009] Furthermore, the sheet resistance of the second metal mesh layer is 0.048Ω / □~0.072Ω / □.

[0010] Furthermore, the isolation layer is an OCA layer or a solid dielectric layer.

[0011] Furthermore, the first metal mesh layer and the corresponding second metal mesh layer form a sensing area, and a sensing circuit portion is provided on the side of the isolation layer facing the first metal mesh layer, with a gap formed between the sensing circuit portion and the sensing area.

[0012] Furthermore, several of the sensing areas are spaced apart, and a drive circuit section is provided on the side of the isolation layer facing the second metal mesh layer, with the drive circuit section located between the sensing circuit section and the sensing area.

[0013] Furthermore, the sensing circuit section includes a plurality of sensing lines, the width of which is 24μm to 26μm and the distance between adjacent sensing lines is 34μm to 36μm. The driving circuit section includes a plurality of driving lines, the width of which is 14μm to 16μm and the distance between adjacent driving lines is 19μm to 21μm.

[0014] A method for fabricating a three-dimensional touch screen with a metal mesh, used to fabricate a three-dimensional touch screen with a metal mesh as described in the above technical solution, the method comprising the following steps: A substrate is provided, the substrate including an isolation layer and metal layers respectively disposed on both sides of the isolation layer; A dry film is laminated on both sides of the substrate, and a patterned photomask is formed on the surface of the dry film to form an exposure module; The module to be exposed is subjected to double-sided exposure to form the module to be etched; The module to be etched is etched on both sides to form a plurality of first metal mesh layers and a plurality of second metal mesh layers on the isolation layer.

[0015] Compared with existing technologies, the advantages of this invention are as follows: Three-dimensional touch control can be achieved through the first and second metal mesh layers. The closed connections and separations of several first metal strips form a micro-capacitor structure. The narrower width improves spatial resolution, and even minute positional changes can cause capacitance changes. This facilitates the accurate calculation of the two-dimensional planar coordinates of the touch area using the capacitance change value. Several second metal strips form a continuous conductive network with a certain resistance value. When pressure is applied during touch, the pressure is transmitted to the second metal mesh layer, causing it to deform and stretch under pressure, resulting in a change in resistance. This change in resistance allows the measurement of pressure perpendicular to the two-dimensional coordinate plane. The three-dimensional touch function does not require an additional pressure sensor, nor does it require additional structural layers or thickness. This allows the metal mesh three-dimensional touch screen to combine the advantages of thinness and lightness with accurate three-dimensional touch measurement, and it does not rely on the mutual capacitance between the two metal mesh layers to measure vertical pressure. This design decouples the measurement of two-dimensional plane coordinates from pressure measurement. By staggering the two metal mesh layers, the area of ​​the metal mesh facing each other between the layers is minimized, significantly reducing the parasitic capacitance between the two metal mesh layers. The parasitic capacitance is extremely small and relatively constant, not changing with pressure. This avoids the situation where the change in interlayer spacing caused by pressure when the two metal mesh layers overlaps, causing the change in interlayer parasitic capacitance to be mixed into the capacitance change value of the first metal mesh layer, thus introducing errors. This further decouples the first metal mesh layer from sensing the two-dimensional coordinates. In addition, the staggered arrangement is also beneficial to reduce the error caused by pressure passing through the first metal strip and causing deformation during pressing. The narrow line width of the second metal mesh layer is beneficial to increase the stretching of the metal and improve the resolution of resistance measurement, thereby obtaining more accurate pressure measurement results. The first and second metal mesh layers do not depend on the change in interlayer spacing to measure capacitance and resistance, improving the reliability and service life of the metal mesh three-dimensional touch screen. Attached Figure Description

[0016] Figure 1 This is a top view of the first metal mesh layer and the second metal mesh layer in the metal mesh three-dimensional touch screen according to the first embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first metal mesh layer in the metal mesh three-dimensional touch screen in the first embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the second metal mesh layer in the metal mesh three-dimensional touch screen in the first embodiment of the present invention; Figure 4 This is a top view of the metal mesh three-dimensional touch screen in the first embodiment of the present invention; Figure 5 This is a flowchart of the metal mesh three-dimensional touch screen fabrication method in the second embodiment of the present invention; Figure 6 This is a surface plot of the capacitance data of the metal mesh three-dimensional touch screen prepared by the metal mesh three-dimensional touch screen preparation method in the second embodiment of the present invention; Explanation of key component symbols: 100, First metal mesh layer; 110, First metal strip; 111, First partition; 200, Second metal mesh layer; 210, Second metal strip; 300, Isolation layer; 310, Sensing area; 320, Sensing circuit section; 330, Drive circuit section.

[0017] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0019] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] Please see Figures 1 to 4The metal mesh three-dimensional touch screen in the first embodiment of the present invention includes a plurality of first metal mesh layers 100 and a plurality of second metal mesh layers 200. Each of the plurality of first metal mesh layers 100 is connected to an isolation layer 300, which is an OCA layer or a solid dielectric layer. The side of the isolation layer 300 facing away from the first metal mesh layer 100 is connected to the plurality of second metal mesh layers 200. Each of the first metal mesh layers 100 includes a plurality of first metal strips 110, the width of which is 2.3μm to 4.3μm. The plurality of first metal strips 110 are interconnected to form a plurality of first closed metal rings. The plurality of first metal strips 110 are connected to form a plurality of first partition portions 111. The first partition portions 111 are located inside the first closed metal rings and are spaced apart from the first closed metal rings. Preferably, the metal material of the first metal mesh layer 100 and the second metal mesh layer 200 is copper, and the isolation layer 300 is an OCA adhesive layer. During the fabrication of the metal mesh 3D touchscreen, a blackening film and a dry film are also used. The metal mesh is created through photolithography, laser engraving, and wet etching processes. The width of the first metal strip 110, i.e., the line width, is a minimum of 3.45 μm, a maximum of 4.21 μm, and an average of 3.94 μm. Understandably, the closed connection and separation of several first metal strips 110 form a microcapacitor structure. The finer width improves spatial resolution, and even a small change in position can cause a change in capacitance, which is beneficial for accurately calculating the two-dimensional planar coordinates of the touch area through the capacitance change value.

[0022] The second metal mesh layer 200 includes a plurality of second metal strips 210. The sheet resistance of the second metal mesh layer 200 is 0.048Ω / □~0.072Ω / □, and the width of the second metal strips 210 is 3μm~5μm. The plurality of second metal strips 210 are interconnected to form a plurality of second closed metal rings. The plurality of second metal strips 210 are connected to form a plurality of second partitions. The second partitions are located inside the second closed metal rings and form a gap with the second closed metal rings. Both the first metal mesh layer 100 and the second metal mesh layer 200 are connected to a signal processing device. The first metal mesh layer 100 is used to measure the capacitance change value to obtain two-dimensional plane coordinates. The second metal mesh layer 200 is used to measure the resistance change value to obtain three-dimensional pressure value. The projections of the first metal strip 110 on the isolation layer 300 and the projections of the second metal strip 210 on the isolation layer 300 are intersected. Preferably, the width, i.e., the line width, of the second metal strip 210 is a minimum of 3.43 μm, a maximum of 4.98 μm, and an average of 4.41 μm. The sheet resistance of the second metal mesh layer 200 is 0.06 Ω / □. The signal processing device distinguishes between the capacitance measurement and resistance measurement modes by time segmentation or frequency multiplexing. Specifically, the time segmentation method is used, and the touch pressure is calibrated by measuring the resistance change value and the pressure. Understandably, several second metal strips 210 form a continuous conductive network with a certain resistance value. When pressure is applied during touch, the pressure is conducted to the second metal mesh layer 200, causing the second metal mesh layer 200 to deform and stretch, generating a resistance change value. The pressure perpendicular to the two-dimensional coordinate plane is obtained through the resistance change value, forming a three-dimensional touch function. The low sheet resistance setting makes the thermal resistance change much smaller than the deformation-induced resistance change, and the pressure detection accuracy avoids the influence of ambient temperature. The narrow line width of the second metal mesh layer 200 is beneficial to increasing the stretching of the metal and improving the sensing accuracy of the resistance change value.

[0023] The first metal mesh layer 100 and the corresponding second metal mesh layer 200 form a sensing area 310. The projection of the first metal mesh layer 100 onto the isolation layer 300 and the projection of the second metal mesh layer 200 onto the isolation layer 300 form a rhombic array. A sensing circuit section 320 is provided on the side of the isolation layer 300 facing the first metal mesh layer 100. The sensing circuit section 320 and the sensing area 310 are spaced apart. A plurality of sensing areas 310 are evenly distributed. The isolation layer 300 faces... A driving circuit section 330 is provided on one side of the second metal mesh layer 200. The driving circuit section 330 is located between the sensing circuit section 320 and the sensing area 310. The sensing circuit section 320 includes a plurality of sensing lines, the width of which is 24μm to 26μm, and the distance between adjacent sensing lines is 34μm to 36μm. The driving circuit section 330 includes a plurality of driving lines, the width of which is 14μm to 16μm, and the distance between adjacent driving lines is 19μm to 21μm. Preferably, the spacing between the rhombus mesh in the rhombus array is 120μm to 500μm, specifically 300μm. Both the sensing circuit section 320 and the driving circuit section 330 are made of copper. The width of the sensing line is 25μm, and the line spacing of the sensing line is 35μm. The width of the driving line is 15μm, and the line spacing of the driving line is 20μm. Understandably, forming a diamond array is beneficial to improving the capacitance flatness of the entire touch screen and eliminating detection blind spots when subjected to force. The dense wiring in the sensing circuit section 320 and the driving circuit section 330 is beneficial to uniformly transmit and receive high-density signals.

[0024] Understandably, the three-dimensional touch function integrated into the metal mesh three-dimensional touch screen does not require the introduction of additional pressure sensors, nor does it require the addition of additional structural layers and thickness, thus combining the advantages of thinness and lightness with accurate three-dimensional touch measurement.

[0025] Furthermore, traditional 3D touchscreens use mutual capacitance or self-capacitance to sense pressure and 2D coordinates. When measuring pressure, it's difficult to decouple the two metal mesh layers. Even with time-division or frequency-division multiplexing, changes in interlayer parasitic capacitance caused by pressure deformation will affect the measurement results of 2D coordinates and pressure. Moreover, the accuracy of pressure measurement is limited by the upper metal mesh and the deformation material in the middle layer. The touchscreen in this embodiment does not rely on the mutual capacitance between the two metal mesh layers to measure vertical pressure, thus decoupling the measurement of 2D plane coordinates from pressure measurement. By staggering the two metal mesh layers, the area of ​​the metal mesh facing each other between the layers is minimized, significantly reducing the parasitic capacitance between the two metal mesh layers. This parasitic capacitance is extremely small and relatively constant, not changing with pressure, avoiding the interference of pressure when the two metal mesh layers overlap. The variation in interlayer spacing can introduce errors by mixing the changes in interlayer parasitic capacitance with the capacitance changes in the first metal mesh layer 100. This further decouples the first metal mesh layer 100 from the two-dimensional coordinates it senses. The staggered arrangement also helps reduce the errors caused by pressure passing through the first metal strip 110 and causing deformation when pressed, allowing the pressure to be transmitted more directly to the second metal mesh layer 200. The isolation layer 300 is made of a dielectric material, providing dielectric isolation and transmitting pressure. This helps the two metal layers focus on capacitance sensing and resistance strain respectively, further improving the decoupling effect. The first metal mesh layer 100 and the second metal mesh layer 200 do not rely on the variation in interlayer spacing to measure capacitance and resistance, improving the reliability and service life of the metal mesh three-dimensional touch screen.

[0026] Please see Figure 5 The second embodiment of the present invention provides a method for fabricating a three-dimensional metal mesh touchscreen, used to fabricate a three-dimensional metal mesh touchscreen as described in the first embodiment above. The method for fabricating a three-dimensional metal mesh touchscreen includes the following steps: Step S10: Provide a substrate, the substrate including an isolation layer and metal layers respectively disposed on both sides of the isolation layer; Preferably, the metal layer on the surface of the substrate is copper, and the main internal material of the substrate is a blackened film with a thickness of 50 μm, and the film material is a dielectric material.

[0027] Step S20: A dry film is laminated on both sides of the substrate, and a patterned photomask is set on the surface of the dry film to form a module to be exposed; Step S30: Perform double-sided exposure on the module to be exposed to form the module to be etched; Step S40: Perform double-sided etching on the module to be etched to form a plurality of first metal mesh layers and a plurality of second metal mesh layers on the isolation layer.

[0028] Preferably, the isolation layer 300 has a size of 28 inches, the diamond mesh spacing formed by the first metal mesh layer 100 and the second metal mesh layer 200 is 300 μm, the width of the first metal strip 110, i.e., the line width, is a minimum of 3.45 μm, a maximum of 4.21 μm, and an average of 3.94 μm, the width of the second metal strip 210, i.e., the line width, is a minimum of 3.43 μm, a maximum of 4.98 μm, and an average of 4.41 μm, and the sheet resistance of the second metal mesh layer 200 is 0.06 Ω / □. For capacitance measurement of the formed touchscreen product, please refer to [link / reference]. Figure 6 With the first metal mesh layer 100 and the second metal mesh layer 200 interleaved to minimize the overlapping area, the product has good compressibility.

[0029] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A metal mesh three-dimensional touch screen, characterized in that, The system comprises several first metal mesh layers and several second metal mesh layers. Each of the first metal mesh layers is connected to an isolation layer. The side of the isolation layer facing away from the first metal mesh layers is connected to the several second metal mesh layers. Each first metal mesh layer includes several first metal strips, which are interconnected to form several first closed metal rings. These first metal strips are also connected to form several first partitions, which are located within the first closed metal rings and are spaced apart from them. Each second metal mesh layer includes several second metal strips, which are interconnected to form several second closed metal rings. These second metal strips are also connected to several second partitions, which are located within the second closed metal rings and are spaced apart from them. Both the first and second metal mesh layers are connected to a signal processing device. The first metal mesh layers are used to measure capacitance changes to obtain two-dimensional planar coordinates, and the second metal mesh layers are used to measure resistance changes to obtain three-dimensional pressure values. The projections of the first metal strips onto the isolation layer and the projections of the second metal strips onto the isolation layer intersect each other.

2. The metal mesh three-dimensional touch screen according to claim 1, characterized in that, The width of the first metal strip is 2.3μm to 4.3μm, and the width of the second metal strip is 3μm to 5μm.

3. The metal mesh three-dimensional touch screen according to claim 1, characterized in that, The first metal mesh layer and the second metal mesh layer are positioned correspondingly. The first metal mesh layer and the corresponding second metal mesh layer form a sensing area. The projection of the first metal mesh layer on the isolation layer and the projection of the second metal mesh layer on the isolation layer form a rhombus array.

4. The metal mesh three-dimensional touch screen according to claim 1, characterized in that, The sheet resistance of the second metal mesh layer is 0.048Ω / □~0.072Ω / □.

5. The metal mesh three-dimensional touch screen according to claim 1, characterized in that, The isolation layer is an OCA layer or a solid dielectric layer.

6. The metal mesh three-dimensional touch screen according to claim 3, characterized in that, The insulating layer has a sensing circuit section on the side facing the first metal mesh layer, and the sensing circuit section is spaced apart from the sensing area.

7. The metal mesh three-dimensional touch screen according to claim 6, characterized in that, The sensing areas are distributed at intervals, and a drive circuit section is provided on the side of the isolation layer facing the second metal mesh layer. The drive circuit section is located between the sensing circuit section and the sensing area.

8. The metal mesh three-dimensional touch screen according to claim 7, characterized in that, The sensing circuit section includes a plurality of sensing lines, the width of which is 24μm to 26μm and the distance between adjacent sensing lines is 34μm to 36μm. The driving circuit section includes a plurality of driving lines, the width of which is 14μm to 16μm and the distance between adjacent driving lines is 19μm to 21μm.

9. A method for fabricating a three-dimensional touchscreen with a metal mesh, used to fabricate a three-dimensional touchscreen with a metal mesh as described in any one of claims 1 to 8, characterized in that, The method for manufacturing the metal mesh three-dimensional touch screen includes the following steps: A substrate is provided, the substrate including an isolation layer and metal layers respectively disposed on both sides of the isolation layer; A dry film is laminated on both sides of the substrate, and a patterned photomask is formed on the surface of the dry film to form an exposure module; The module to be exposed is subjected to double-sided exposure to form the module to be etched; The module to be etched is etched on both sides to form a plurality of first metal mesh layers and a plurality of second metal mesh layers on the isolation layer.

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