Capacitive membrane switch

Abstract

The utility model discloses a capacitive membrane switch, which comprises a control panel, an ITO (Indium Tin Oxide) membrane, a TX silver paste wire, an RX silver paste wire and an insulating unit, the ITO thin film is arranged on the control panel, and a plurality of ITO circuit patterns are arranged on the ITO thin film; the TX silver paste wires and the RX silver paste wires are arranged on the upper surface of the ITO thin film in a mutual non-interference manner, and the TX silver paste wires and the RX silver paste wires are in lap joint with the ITO circuit patterns respectively; and an intersection area with an insulation unit is arranged between the TX silver paste wire and the RX silver paste wire. According to the utility model, the TX silver paste wire and the RX silver paste wire which are not interfered with each other and are insulated are printed on the ITO film, the TX silver paste wire and the RX silver paste wire are respectively connected with the corresponding ITO circuit patterns, each ITO circuit pattern can realize the switching function of the film switch, and the change of current and voltage is caused by touching the ITO circuit patterns, so that the film switch can be realized. And the touch position is accurately positioned, and response opening and closing are carried out through an IC algorithm.

Description

Technical Field

[0001] The utility model relates to the technical field of membrane switches, in particular to a capacitive membrane switch. Background Art

[0002] A membrane switch is an operating system that integrates key functions, indicator elements, and instrument panels. It is generally used in automotive industrial control fields such as central control instruments, home appliances, and medical devices. The switching mode of a membrane switch generally adopts mechanical forms such as push-button or rotary. However, if the switch is pressed or rotated for a long time, it is easy to cause device wear and failure, resulting in failure of the product's switch function. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and to provide a capacitive membrane switch with high reliability and long service life.

[0004] To achieve the above object, the technical solution adopted by the utility model is: a capacitive membrane switch, comprising: a control panel, an ITO film, a TX silver paste wiring, an RX silver paste wiring and an insulation unit;

[0005] The ITO film is arranged on the upper surface of the control panel, and a plurality of ITO circuit patterns are arranged on the ITO film;

[0006] The TX silver paste traces and the RX silver paste traces are arranged on the upper surface of the ITO film without interfering with each other, and the TX silver paste traces and the RX silver paste traces are respectively overlapped with the ITO circuit pattern to form a separate touch circuit with each of the ITO circuit patterns; wherein, a cross region is further provided between the TX silver paste traces and the RX silver paste traces;

[0007] The insulating unit is disposed in the intersection area to insulate the TX silver paste wiring from the RX silver paste wiring.

[0008] Furthermore, carbon paste is printed on the upper surfaces of the TX silver paste wiring and the RX silver paste wiring.

[0009] Furthermore, the thickness of the TX silver paste wiring and the RX silver paste wiring are both 5 to 10 μm.

[0010] Furthermore, an explosion-proof membrane is provided on the upper surface of the carbon slurry.

[0011] Furthermore, the explosion-proof membrane is made of TAC.

[0012] Furthermore, the line width and line spacing of the TX silver paste routing and the RX silver paste routing are the same; wherein, the line width is 500±70um, and the line spacing is 500±70um.

[0013] Furthermore, a crossing area is provided between the TX silver paste routing and the RX silver paste routing, and the TX silver paste routing is located below the RX silver paste routing.

[0014] Furthermore, the insulating unit includes a first insulating layer and a second insulating layer that are connected to each other; wherein the first insulating layer and the second insulating layer are both covered in the intersection area, and the area of ​​the first insulating layer is smaller than that of the second insulating layer.

[0015] Furthermore, the first insulating layer and the second insulating layer are both made of insulating ink.

[0016] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0017] The capacitive membrane switch of this utility model prints TX silver paste traces and RX silver paste traces on the ITO film, which do not interfere with each other and are insulated in the cross-region by an insulating unit. The TX silver paste traces and the RX silver paste traces are respectively connected to corresponding ITO circuit patterns. Each ITO circuit pattern can realize the on / off function of the membrane switch. By touching the ITO circuit pattern to cause changes in current and voltage, the touch position can be accurately located and the IC algorithm can be used to respond to on and off, thereby improving the service life and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The technical solution of the utility model is further described below with reference to the accompanying drawings:

[0019] Figure 1 A top view of an embodiment of the present invention;

[0020] Figure 2 for Figure 1 A magnified view of part A in FIG;

[0021] Figure 3 for Figure 1 A magnified view of part B in FIG;

[0022] Figure 4 for Figure 3 Enlarged view of part C in ;

[0023] Figure 5 This is a connection diagram of the TX silver paste routing, the RX silver paste routing, and the insulation unit in one embodiment of the present invention;

[0024] Figure 6 This is a connection diagram of the TX silver paste wiring, the RX silver paste wiring and the insulation unit in another embodiment of the present invention;

[0025] Among them: control panel 1, ITO film 2, TX silver paste wiring 3, RX silver paste wiring 4, insulation unit 5, carbon paste 6, ITO circuit pattern 20, first insulation layer 50, second insulation layer 51. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0027] The utility model provides a capacitive membrane switch to solve the problem that the switching mode of membrane switches in the prior art generally adopts mechanical forms such as pressing or rotating, and long-term pressing or rotating can easily cause device wear and failure, resulting in failure of the product switch function.

[0028] For ease of understanding, the specific process in the embodiment of this application is described below. Figures 1 to 3 A capacitive membrane switch in an embodiment of the present application includes a control panel 1, an ITO film 2, a TX silver paste trace 3, an RX silver paste trace 4 and an insulating unit 5; the ITO film 2 is arranged on the upper surface of the control panel 1, and a plurality of ITO circuit patterns 20 arranged in sequence are provided on the ITO film 2; the TX silver paste trace 3 and the RX silver paste trace 4 are arranged on the upper surface of the ITO film 2 without interfering with each other, and the TX silver paste trace 3 and the RX silver paste trace 4 are respectively overlapped with the ITO circuit pattern 20 to form a separate touch circuit with each of the ITO circuit patterns 20; wherein, a crossing area is also provided between the TX silver paste trace 3 and the RX silver paste trace 4; the insulating unit 5 is provided in the crossing area to insulate the TX silver paste trace 3 and the RX silver paste trace 4.

[0029] The capacitive membrane switch of the present invention prints TX silver paste traces and RX silver paste traces that do not interfere with each other on the ITO film 2, and uses an insulating unit to effectively isolate the intersection of the TX silver paste traces and the RX silver paste traces. The TX silver paste traces and the RX silver paste traces are respectively connected to corresponding ITO circuit patterns. Each ITO circuit pattern can realize the switching function of the membrane switch. By touching the ITO circuit pattern to cause changes in current and voltage, the touch position can be accurately located and the IC algorithm can be used to respond to on and off, avoiding mechanical work, thereby improving service life and high reliability.

[0030] Further, based on Figure 1 and Figure 2 Carbon paste 6 is also printed on the upper surface of the TX silver paste trace and the RX silver paste trace. Figure 2 Only a portion of the carbon paste 6 is displayed. If the entire carbon paste 6 is displayed, the TX silver paste traces and the RX silver paste traces cannot be seen.

[0031] Specifically, the carbon paste 6 is composed of carbon powder, organic resin, organic solvent, etc., and is printed on the surface of the TX silver paste trace 3 and the RX silver paste trace 4 through high-precision screen printing technology, with a printing thickness of 5 to 10 um, thereby enhancing the wear resistance and bending resistance of the two silver paste traces, and reducing the risk of silver paste breakage when the capacitive membrane switch is frequently used.

[0032] Furthermore, an explosion-proof film is provided on the upper surface of the carbon paste 6. The explosion-proof film is composed of a TAC substrate with a thickness of generally 40um, 60um, and 80um. The surface is subjected to various surface treatments such as AG, AR, AF, and HC. The surface hardness is 500g 6H, AF>110℃, and AR<0.5%. The transmittance can reach more than 95%, and the friction resistance is improved to more than 100,000 times, thereby enhancing the transparency and wear resistance of the capacitive membrane switch.

[0033] Furthermore, in this embodiment, the TX silver paste wiring and the RX silver paste wiring are made of the same material, both consisting of silver powder, organic resin, organic solvent, etc., and are printed on the upper surface of the ITO film 2 using high-precision screen printing technology, with a printing thickness of 5 to 10 um.

[0034] And, according to square resistance = (resistivity Length) / (Width Thickness) formula shows that the resistivity of silver paste is an inherent property of silver paste and does not change. The length of the silver paste trace is fixed according to the shape of the membrane switch, and the silver paste printing thickness does not change significantly under certain printing parameters. Therefore, when the width of the silver paste trace is larger, the square resistance of the silver paste trace will be lower, resulting in improved touch response sensitivity. In this embodiment, the line width and line spacing of TX silver paste trace 3 and RX silver paste trace 4 are designed to be larger, with a line width of 500±70μm and a line spacing of 500±70μm.

[0035] In addition, in this embodiment, the TX silver paste trace 3 and the RX silver paste trace 4 are respectively overlapped with the corresponding ITO circuit pattern 20 in the capacitive membrane switch, and the TX silver paste trace 3 and the RX silver paste trace 4 are jointly overlapped with the same ITO circuit pattern 20 to form a touch circuit, which is used to realize the conduction function of each membrane switch button, so that each can work independently.

[0036] Further, based on Figure 3 and Figure 4 In this embodiment, the insulating unit 5 is printed in the intersection area of ​​the TX silver paste trace 3 and the RX silver paste trace 4. The insulating unit 5 is located above the TX silver paste trace and below the RX silver paste trace, that is, between the TX silver paste trace and the RX silver paste trace. The printing thickness of each layer is 2 to 4 um.

[0037] The insulating unit 5 includes a first insulating layer 50 and a second insulating layer 51 which are connected to each other. The first insulating layer 50 and the second insulating layer 51 can both be arranged on the upper layer, but it is necessary to ensure that the first insulating layer 50 and the second insulating layer 51 are both covered in the intersection area. At the same time, the area of ​​the first insulating layer 50 is smaller than the area of ​​the second insulating layer 51. The two layers of insulating oil layers are used to form a step difference, enhance the sealing and protection, and increase the ability to isolate the silver paste routing in the intersection area of ​​the TX silver paste routing and the RX silver paste routing, so as to prevent the short circuit caused by the connection between the TX silver paste routing and the RX silver paste routing.

[0038] Therefore, based on Figure 4 and Figure 5 In this embodiment, the TX silver paste trace 3 is located below the RX silver paste trace 4, and the first insulating layer 50 is located above the second insulating layer 51. First, the second insulating layer 51 is printed to cover the upper surface of the TX silver paste trace 3, and then the first insulating layer 50 is printed to cover the upper surface of the second insulating layer 51. Then, the first insulating layer 50 contacts and isolates the RX silver paste trace 4. In this way, the TX silver paste trace 3 and the RX silver paste trace 4 can be well isolated, and both the first insulating layer 50 and the second insulating layer 51 can cover the intersection area of ​​the TX silver paste trace 3 and the RX silver paste trace 4.

[0039] based on Figure 4 and Figure 6 In another embodiment, the TX silver paste trace 3 is located below the RX silver paste trace 4, and the second insulating layer 51 is located above the first insulating layer 50. The first insulating layer 50 is first printed and covered on the upper surface of the TX silver paste trace 3, and then the second insulating layer 51 is printed and covered on the upper surface of the first insulating layer 50, and extends to both sides to the upper surface of the TX silver paste trace 3 for printing and covering. At the same time, the second insulating layer 51 contacts the RX silver paste trace 4, and can also well isolate the TX silver paste trace 3 and the RX silver paste trace 4. At this time, the first insulating layer 50 and the second insulating layer 51 can also cover the intersection area of ​​the TX silver paste trace 3 and the RX silver paste trace 4.

[0040] In addition, the highly transparent insulation has a transmittance of ≥99%, which can increase the transmittance of the membrane switch by more than 0.5%~1%, further improving the transmittance of the membrane switch.

[0041] In addition, the first insulating layer 50 and the second insulating layer 51 are both made of insulating ink, which is mainly composed of components such as polyol resin, acrylic resin, and organic solvent.

[0042] Furthermore, the ITO film 2 is formed by coating a 30-100 nm thick ITO layer on a 50 μm thick COP substrate. The ITO film then undergoes a yellow light process including aging, exposure, development, etching, and stripping to produce an ITO circuit pattern 20 having multiple specific patterns. In this membrane switch, one ITO circuit pattern 20 corresponds to one membrane switch, serving as the conductive layer for implementing the membrane switch.

[0043] Among them, the substrate of the ITO film 2 is COP material with a transmittance of ≥92%. The transmittance of a conventional PET film substrate is ≥90%. Relatively speaking, the transmittance of this membrane switch is higher.

[0044] In addition, the ITO film 2 is provided on the control panel 1 through an adhesive. The adhesive in this embodiment is a solid optical transparent adhesive with high transmittance and great viscosity. The thickness is generally 150um, 175um, 200um, 250um, etc.

[0045] Furthermore, the control panel 1 is a cover with a silk-screen pattern, the material of which can be a film such as PET, PC, ABS, or a hard material such as CG, hardware, etc. The silk-screen pattern corresponds to the position of each membrane switch and is used to identify the position and function of the switch. The thickness is 0.4mm to 2mm and is mainly used to protect the functional components of the membrane switch.

[0046] In summary, in the capacitive membrane switch of the present invention, carbon paste, TX silver paste wiring, insulation, RX silver paste wiring, and ITO film constitute the functional components of the membrane switch, and its structural design diagram is shown in FIG. Figure 2 When a user touches the ITO circuit pattern of any membrane switch, the membrane switch transmits the signal to the IC based on the silver paste traces connected to the ITO circuit pattern. The IC algorithm responds to the position and realizes the touch function.

[0047] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A capacitive membrane switch, characterized in that: include: Control panel, ITO film, TX silver paste wiring, RX silver paste wiring and insulation unit; The ITO film is arranged on the upper surface of the control panel, and a plurality of ITO circuit patterns are arranged on the ITO film; The TX silver paste traces and the RX silver paste traces are arranged on the upper surface of the ITO film without interfering with each other, and the TX silver paste traces and the RX silver paste traces are respectively overlapped with the ITO circuit pattern to form a separate touch circuit with each of the ITO circuit patterns; wherein, a cross region is further provided between the TX silver paste traces and the RX silver paste traces; The insulating unit is disposed in the intersection area to insulate the TX silver paste wiring from the RX silver paste wiring.

2. The capacitive membrane switch according to claim 1, wherein: Carbon paste is also printed on the upper surfaces of the TX silver paste wiring and the RX silver paste wiring.

3. The capacitive membrane switch according to claim 1, wherein: The thickness of the TX silver paste wiring and the RX silver paste wiring are both 5 to 10 μm.

4. The capacitive membrane switch according to claim 2, wherein: An explosion-proof membrane is also provided on the upper surface of the carbon slurry.

5. The capacitive membrane switch according to claim 4, wherein: The explosion-proof membrane is made of TAC.

6. The capacitive membrane switch according to claim 1, wherein: The line width and line spacing of the TX silver paste routing and the RX silver paste routing are the same; wherein, the line width is 500±70um, and the line spacing is 500±70um.

7. The capacitive membrane switch according to claim 1, wherein: A crossing area is further provided between the TX silver paste routing and the RX silver paste routing, and the TX silver paste routing is located below the RX silver paste routing.

8. The capacitive membrane switch according to claim 1, wherein: The insulating unit includes a first insulating layer and a second insulating layer which are connected to each other; wherein the first insulating layer and the second insulating layer are both covered in the intersection area, and the area of ​​the first insulating layer is smaller than that of the second insulating layer.

9. The capacitive membrane switch according to claim 8, wherein: The first insulating layer and the second insulating layer are both made of insulating ink.

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