Capacitive pressure sensor applied to TWS earphone key detection

Abstract

The invention discloses a capacitive pressure sensor applied to TWS earphone key detection, and belongs to the technical field of pressure sensors. The capacitive pressure sensor comprises a pressure sensing unit and a PCB part; the pressure sensing unit is used for sensing external pressure and generating telescopic deformation, the PCB part is provided with a capacitance detection unit, the capacitance detection unit is used for detecting capacitance change generated by deformation, and the capacitance change is read through a capacitance detection circuit and converted into a pressure value to be output. The capacitive pressure sensor can effectively extract a pressing signal and convert the pressing signal into a capacitance signal, and then a pressure value is read through the high-performance capacitance detection chip. The structure has the advantages of simple assembly, low cost, high reliability and strong anti-interference capability, and is very suitable for pressure detection application of the TWS earphone.

Description

Technical Field

[0001] The present invention belongs to the technical field of pressure sensors, and specifically, relates to a capacitive pressure sensor used for TWS headset button detection. Background Art

[0002] Pressure-sensing control is the latest interactive method used on TWS earphones, which controls various functions by sensing changes in pressure. It has a precision close to that of physical buttons but does not require holes. It is more accurate than touch buttons and avoids the stethoscope effect caused by accidental touches and tapping.

[0003] In the past, capacitive touch sensor solutions on TWS earphones had disadvantages such as "easy to accidentally touch, single operation action, and affected experience"; in contrast, pressure-sensitive touch solutions have many advantages such as anti-accidental touch, accurate operation, rich logic, and friendly experience.

[0004] At present, the traditional TWS headset pressure detection solution is based on thin-film resistors. The figure below is a schematic diagram of the solution. The green is the PCB board. The pressure sensing module on the PCB board is buckled on the main board and then inserted into the earphone handle, and the spring is pushed to the inner wall of the ear handle; when the user presses, the ear handle produces a slight deformation, causing the spring to deform accordingly. The pressure sensing module detects the deformation of the spring and generates a resistance change. The signal is read out through the detection chip and converted into a pressing signal.

[0005] At present, the thin film pressure sensor has the problems of high production cost, low yield and poor consistency, and is difficult to be popularized on a large scale. It is only used in high-end TWS headphones. In order to solve the above problems, the present invention provides the following technical solutions. Summary of the invention

[0006] The purpose of the present invention is to provide a capacitive pressure sensor for TWS headset button detection, so as to solve the problems of high production cost, low yield and poor consistency of thin film pressure sensors in the pressure detection scheme commonly used in TWS headsets in the prior art.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A capacitive pressure sensor for TWS headset button detection, including a pressure sensing unit and a PCB part;

[0009] The pressure sensing unit is used to sense external pressure and generate expansion and contraction deformation. A capacitance detection unit is provided on the PCB part. The capacitance detection unit is used to detect the capacitance change caused by the deformation, and read it out through the capacitance detection circuit and convert it into a pressure value output.

[0010] As a further solution of the present invention, the pressure sensing unit includes a pressure sensing element, a capacitive sensing element, a distance control unit and a fixing column which are fixedly connected in sequence from top to bottom;

[0011] The height of the distance control unit will expand or contract according to the magnitude of the pressure transmitted by the pressure sensing element.

[0012] As a further solution of the present invention, the capacitance detection unit includes a shielding layer, a pressure sensing end, and an inner column placement blind hole;

[0013] The shielding layer is grounded on the PCB board. The PCB board is also provided with an inner column placement blind hole. The inner column placement blind hole is short-circuited with the ground layer of the PCB board. The fixing column on the pressure sensing unit is inserted into the inner column placement blind hole and fixed by welding.

[0014] The shielding layer is also provided with a pressure sensing end, which is a concentric ring in which the blind hole is placed on the inner column. The pressure sensing end is realized by copper plating on the PCB board; and then connected to the input end of the pressure sensing chip through the PCB board wiring;

[0015] As a further solution of the present invention, the capacitance detection unit also includes a shielding ring arranged on the outer layer of the pressure sensing end, the shielding ring is realized by plating copper on the PCB board, and the shielding ring and the pressure sensing end are concentric rings, and the shielding ring is short-circuited with the ground layer of the PCB board.

[0016] As a further solution of the present invention, the inner column blind hole, the pressure sensing end and the shielding ring are all within the range of the shielding layer.

[0017] As a further solution of the present invention, a layer of elastic medium is fixed on the top of the pressure sensing element, and the elastic medium is in direct contact with the inner wall of the earphone handle.

[0018] Beneficial effects of the present invention:

[0019] The capacitive pressure sensor of the present invention can effectively extract the pressing signal and convert it into a capacitive signal, and then read the pressure value through a high-performance capacitive detection chip. The structure is simple to assemble, low in cost, high in reliability, and strong in anti-interference ability, and is very suitable for pressure detection applications in TWS headphones. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 is a schematic structural diagram of the capacitive pressure sensor of the present invention;

[0022] Figure 2 is a schematic diagram of installing the capacitive pressure sensor of the present invention on an earphone;

[0023] Figure 3 is a structural schematic diagram of a capacitance detection unit;

[0024] Figure 4 is a schematic diagram of the structure of the pressure sensing unit;

[0025] Figure 5 This is the waveform diagram of the pressure detection of the capacitive pressure sensor in actual use.

[0026] In the figure: 1. pressure sensing unit; 2. capacitance detection unit; 3. elastic medium; 11. pressure sensing part; 12. capacitance sensing element; 13. distance control unit; 14. fixing column; 21. blind hole for inner column; 22. pressure sensing end; 23. shielding ring; 24. shielding layer. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A capacitive pressure sensor used for TWS headset button detection, such as Figures 1 to 3 As shown, it includes a pressure sensing unit 1 and a PCB part, wherein the pressure sensing unit 1 can directly sense external pressure and produce expansion and contraction deformation, and a capacitance detection unit 2 with a shielding function is designed on the PCB part. When the pressure sensing unit 1 is pressed, the pressure sensing unit 1 is deformed, and the capacitance detection unit 2 on the PCB part detects a small capacitance change caused by the deformation, and the change is read out by the capacitance detection circuit and converted into a pressure value;

[0029] The pressure sensing unit 1 comprises a pressure sensing element 11, a capacitive sensing element 12, a distance control unit 13 and a fixing column 14 which are fixedly connected in sequence from top to bottom;

[0030] The pressure sensing element 11 is used to sense external pressure and transmit the pressure to the distance control unit 13. The height of the distance control unit 13 will expand or contract according to the pressure transmitted by the pressure sensing element 11, that is, the height of the distance control unit 13 can directly reflect the pressure.

[0031] The capacitance detection unit 2 on the PCB portion includes a shielding layer 24, a shielding ring 23, a pressure sensing end 22, and an inner column placement blind hole 21;

[0032] The shielding layer 24 is grounded on the PCB board to shield the signal interference from the other side. The PCB board is also provided with an inner column placement blind hole 21, and the inner column placement blind hole 21 is short-circuited with the ground layer of the PCB board. When connecting the pressure sensing unit 1 and the PCB part, the fixing column 14 on the pressure sensing unit 1 is inserted into the inner column placement blind hole 21 and fixed by welding;

[0033] The shielding layer 24 is also provided with a pressure sensing end 22, which is a concentric ring in which the blind hole 21 is placed on the inner column. The pressure sensing end 22 is realized by copper plating on the PCB board; and then connected to the input end of the pressure sensing chip through the PCB board wiring;

[0034] The outer layer of the pressure sensing end 22 is a shielding ring 23 , which is realized by copper plating on the PCB board. The shielding ring 23 and the pressure sensing end 22 are concentric rings, and the shielding ring 23 is short-circuited with the ground layer of the PCB board.

[0035] The inner column placement blind hole 21 , the pressure sensing end 22 and the shielding ring 23 are all within the range of the shielding layer 24 .

[0036] like Figure 5 As shown, when the capacitive pressure sensor of the present invention is specifically applied in headphones, in TWS headphones, the capacitive pressure sensor is used to identify the user's pressing operation. When the user presses the headphones, the capacitive pressure sensor senses the pressure change and converts it into a capacitive signal, which is then converted into a digital signal through a high-performance capacitive detection circuit on the headphones. Each peak in the figure represents a pressing action of the user. The data shows that the pressure sensor can sense all the user's pressing operations, ensuring a comfortable customer experience.

[0037] like Figure 2 As shown, in a preferred embodiment of the present invention, the capacitive pressure sensor of the present invention is installed in an earphone, specifically, the capacitive pressure sensor is fixed as a whole in the earphone handle, and the top of the capacitive pressure sensor, that is, the pressure sensing element 11 can be in direct contact with the inner wall of the earphone handle, or

[0038] A layer of elastic medium 3 is fixed on the top of the pressure sensing element 11, and the elastic medium 3 is in direct contact with the inner wall of the earphone handle; the elastic medium can be foam, elastic rubber, etc.;

[0039] During use, when the user applies pressure to the position of the pressure sensing element 11 in the earphone handle, the earphone handle will be deformed, and the pressure will be transmitted to the pressure sensing element 11 through the earphone handle and converted into a digital signal through a high-performance capacitive sensor chip.

[0040] The capacitive pressure sensor of the present invention can effectively extract the pressing signal and convert it into a capacitive signal, and then read the pressure value through a high-performance capacitive detection chip. The structure is simple to assemble, low in cost, high in reliability, and strong in anti-interference ability, and is very suitable for pressure detection applications in TWS headphones.

[0041] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A capacitive pressure sensor for TWS headset button detection, characterized in that: It includes a pressure sensing unit (1) and a PCB part; The pressure sensing unit (1) is used to sense external pressure and generate expansion and contraction deformation. A capacitance detection unit (2) is arranged on the PCB part. The capacitance detection unit (2) is used to detect the capacitance change generated by the deformation, and read it out through a capacitance detection circuit and convert it into a pressure value output.

2. A capacitive pressure sensor for TWS headset button detection according to claim 1, characterized in that: The pressure sensing unit (1) comprises a pressure sensing element (11), a capacitive sensing element (12), a distance control unit (13) and a fixing column (14) which are fixedly connected in sequence from top to bottom; The height of the distance control unit (13) will expand or contract according to the magnitude of the pressure transmitted by the pressure sensing element (11).

3. A capacitive pressure sensor for TWS headset button detection according to claim 2, characterized in that: The capacitance detection unit (2) comprises a shielding layer (24), a pressure sensing end (22), and an inner column placement blind hole (21); The shielding layer (24) is grounded on the PCB board. The PCB board is also provided with an inner column placement blind hole (21). The inner column placement blind hole (21) is short-circuited with the ground layer of the PCB board. The fixing column (14) on the pressure sensing unit (1) is inserted into the inner column placement blind hole (21) and fixed by welding. The shielding layer (24) is also provided with a pressure sensing end (22), which is a concentric ring in which the blind hole (21) is placed on the inner column. The pressure sensing end (22) is realized by copper plating on the PCB board; and then connected to the input end of the pressure sensing chip through the PCB board wiring.

4. A capacitive pressure sensor for TWS headset button detection according to claim 3, characterized in that: The capacitance detection unit (2) further comprises a shielding ring (23) arranged on the outer layer of the pressure sensing end (22); the shielding ring (23) is realized by copper plating on a PCB board; the shielding ring (23) and the pressure sensing end (22) are concentric circular rings; and the shielding ring (23) is short-circuited with a ground layer of the PCB board.

5. A capacitive pressure sensor for TWS headset button detection according to claim 4, characterized in that: The inner column placement blind hole (21), the pressure sensing end (22) and the shielding ring (23) are all within the range of the shielding layer (24).

6. A capacitive pressure sensor for TWS headset button detection according to claim 4, characterized in that: A layer of elastic medium (3) is fixed on the top of the pressure sensing element (11), and the elastic medium (3) is in direct contact with the inner wall of the earphone handle.

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