Capacitive touch key

Abstract

The utility model discloses a capacitive touch key, which comprises a circuit board connected with a touch screen and a wave absorbing plate, the wave absorbing plate is arranged on the back of the circuit board and / or a flat cable, the anti-interference performance of the capacitive touch key is increased by covering the wave absorbing plate on the back of the circuit board and / or the flat cable and an electronic element, and compared with an existing product, the capacitive touch key is simple and convenient to improve and low in cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of capacitive touch keys, and more specifically, relates to a capacitive touch key. Background Art

[0002] In recent years, with the development of touch technology, especially capacitive touch technology, the application of capacitive touch buttons has shown a rapid growth trend, replacing mechanical buttons and widely used in home appliances, audio-visual equipment, computer peripherals and car dashboards. However, during use, the sensitivity and false touch rate of touch buttons will be unavoidable topics, especially in the complex electromagnetic environment of the car, where the risk of external interference is also higher.

[0003] Principle of capacitive touch button: There is an inductive capacitance between any two conductive objects. A button, that is, a pad and the ground can also form an inductive capacitance. Under the condition that the surrounding environment remains unchanged, the inductive capacitance value is a fixed and small value. When a human finger approaches the touch button, the inductive capacitance formed by the human finger and the ground is connected in parallel with the inductive capacitance formed by the pad and the ground, which will increase the total inductive capacitance value. After detecting that the inductive capacitance value of a certain button has changed, the capacitive touch button IC will output a confirmation signal that a certain button has been pressed.

[0004] Capacitive touch buttons have no mechanical structure, and all detections are small changes in electricity, so they are more sensitive to various interferences. Currently, many application solutions adopt the method of adding power filter circuits on PCB to avoid the influence of electromagnetic interference, and some even sacrifice the touch sensitivity when electromagnetic interference is detected to suppress electromagnetic interference. The former will increase the system cost (such as the cost of the power module), and the latter, in a continuous electromagnetic interference environment, although it ensures no false triggering, the response to the touch button is slow, or it does not respond to the touch button at all. Utility Model Content

[0005] The utility model aims to solve the problems of weak anti-interference performance and high improvement cost of the existing capacitive touch keys, which affect the use, in view of the deficiencies in the prior art.

[0006] In order to achieve the above object, the utility model provides a capacitive touch button, comprising:

[0007] A circuit board connected with a touch screen;

[0008] The wave absorbing sheet is arranged on the back side of the circuit board and / or the cable.

[0009] Optionally, the wave absorbing sheet comprises:

[0010] A dielectric layer, one side of which is connected to the circuit board via an adhesive layer;

[0011] The magnetic layer is arranged on the other side of the dielectric layer.

[0012] Optionally, the absorbing sheet is also arranged on the capacitive element of the circuit board.

[0013] Optionally, the wave absorbing sheet is in sheet shape.

[0014] Optionally, the absorbing sheet includes a plurality of sheet bodies, and the plurality of sheet bodies are respectively arranged on the capacitor element and the wiring.

[0015] Optionally, adjacent parts of the plurality of sheets are overlapped in sequence.

[0016] Optionally, the absorbing plate is rectangular, and the back side of the circuit board is arranged inside the rectangle.

[0017] Optionally, the wave absorbing plate follows the shape of the circuit board.

[0018] Optionally, there is a heat insulation layer between the magnetic layer and the dielectric layer.

[0019] Optionally, a surface layer is provided on a side of the magnetic layer away from the dielectric layer.

[0020] The utility model provides a capacitive touch button, which has the following beneficial effects:

[0021] The capacitive touch button increases the anti-interference performance by covering the back of the circuit board and / or the wiring and electronic components with an absorbing sheet, and is simple, convenient and low-cost compared to existing products.

[0022] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present invention.

[0024] Figure 1 A schematic diagram showing the position of a wave absorbing sheet of a capacitive touch button according to an embodiment of the utility model is shown.

[0025] Figure 2 A schematic structural diagram of a wave absorbing sheet for a capacitive touch button according to an embodiment of the utility model is shown.

[0026] Description of reference numerals:

[0027] 1. Circuit board; 2. Absorber; 3. Dielectric layer; 4. Magnetic layer; 5. Cable. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0029] like Figure 1-2 As shown, a capacitive touch button includes:

[0030] A circuit board 1 is connected with a touch screen;

[0031] The wave absorbing sheet 2 is arranged on the back side of the circuit board 1 and / or the flat cable 5 .

[0032] Specifically, the circuit board 1 of the touch screen is covered with a composite absorbing material. The main function of the absorbing material is to absorb coupled electromagnetic waves to prevent the superposition of electromagnetic waves and eliminate the redundant electromagnetic waves in the intelligent electronic system. The absorbing material is cut and formed, and attached to the back of the circuit board 1 or the flat cable 5 to resist electromagnetic interference and optimize the performance of the touch screen. By setting the absorbing sheet 2 at the place where the circuit board 1 is easily interfered by the external environment, the anti-interference ability is improved.

[0033] In this embodiment, the absorbing sheet 2 includes:

[0034] A dielectric layer 3, one side of which is connected to the circuit board 1 via an adhesive layer;

[0035] The magnetic layer 4 is disposed on the other side of the dielectric layer 3 .

[0036] Specifically, part of the electromagnetic wave will be reflected on the surface of the material, and the other part will enter the magnetic layer 4 to be absorbed or attenuated, absorbing a large amount of electromagnetic wave energy through hysteresis loss, ferromagnetic resonance and eddy current loss, and converting it into heat energy to achieve wave absorption. After that, the attenuated electromagnetic wave is reflected and weakened by the dielectric layer 3.

[0037] In this embodiment, the absorbing sheet 2 is also disposed on the capacitor element of the circuit board 1 .

[0038] Specifically, protecting components susceptible to interference.

[0039] In this embodiment, the absorbing plate 2 is in a sheet shape.

[0040] In this embodiment, the absorbing sheet 2 includes a plurality of sheets, and the plurality of sheets are respectively disposed on the capacitor element and the wiring 5 .

[0041] Specifically, sheets of different sizes and shapes are cut and attached to the circuit board 1 to adapt to different structural layouts.

[0042] In this embodiment, adjacent parts of a plurality of sheets are overlapped in sequence.

[0043] Specifically, adjacent sheets overlap each other to avoid gaps.

[0044] In this embodiment, the absorbing plate 2 is rectangular, and the back side of the circuit board 1 is arranged inside the rectangle.

[0045] Specifically, the back side of the circuit board 1 is shielded as a whole to ensure the electromagnetic shielding effect.

[0046] In this embodiment, the absorbing plate 2 follows the shape of the circuit board 1 .

[0047] In this embodiment, there is a heat insulation layer between the magnetic layer 4 and the dielectric layer 3 .

[0048] Specifically, the magnetic layer 4 and the dielectric layer 3 are connected via the heat insulation layer, while avoiding mutual interference between the two.

[0049] In this embodiment, a surface layer is disposed on a side of the magnetic layer 4 away from the dielectric layer 3 .

[0050] Specifically, the surface layer can mark the contents of the covered area to facilitate inspection and maintenance positioning.

[0051] When the capacitive touch button of this embodiment is used, taking the use of the automotive touch air-conditioning panel as an example, the air-conditioning panel needs to be tested for radiation RE and handheld radiation immunity test. When handheld radiation immunity is used, the "warning light" button is accidentally touched, causing the double flash lights to turn on. After investigation, it is mainly due to the change in the magnetic field of the line between the touch panel and the IC, which causes a brief change in the capacitance value, resulting in the "false touch" phenomenon. Then, an absorber 2 is added to the signal routing of the air-conditioning control panel PCB to reduce electromagnetic interference at the routing, and then tested again, and no "false triggering" phenomenon occurs.

[0052] The various embodiments of the utility model have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A capacitive touch button, characterized in that: include: A circuit board connected with a touch screen; An absorber is arranged on the back of the circuit board and / or the cable; The wave absorbing sheet comprises: A dielectric layer, one side of which is connected to the circuit board via an adhesive layer; The magnetic layer is arranged on the other side of the dielectric layer.

2. The capacitive touch button according to claim 1, characterized in that: The wave absorbing sheet is also arranged on the capacitor element of the circuit board.

3. The capacitive touch button according to claim 2, characterized in that: The wave absorbing sheet is in sheet shape.

4. The capacitive touch button according to claim 2, characterized in that: The wave absorbing sheet includes a plurality of sheet bodies, and the plurality of sheet bodies are respectively arranged on the capacitor element and the wiring.

5. The capacitive touch button according to claim 4, characterized in that: Adjacent parts of the plurality of sheets are overlapped in sequence.

6. The capacitive touch button according to claim 4, characterized in that: The wave absorbing plate is rectangular, and the back side of the circuit board is arranged inside the rectangle.

7. The capacitive touch button according to claim 4, characterized in that: The wave absorbing plate follows the shape of the circuit board.

8. The capacitive touch button according to claim 1, characterized in that: A heat insulating layer is provided between the magnetic layer and the dielectric layer.

9. The capacitive touch button according to claim 1, characterized in that: A surface layer is disposed on a side of the magnetic layer away from the dielectric layer.

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