Capacitive proximity sensor and electronic device

Abstract

The embodiment of the utility model provides a capacitive proximity sensor and electronic equipment, and the capacitive proximity sensor comprises a detection electrode and an oscillation circuit which is electrically connected with the detection electrode. The detection electrode comprises a main electrode, a first grounding electrode surrounding the radial outer side of the main electrode, an auxiliary electrode arranged opposite to the main electrode, and a second grounding electrode surrounding the radial outer side of the auxiliary electrode. The annular grounding electrode surrounds the radial outer side of the first grounding electrode and the radial outer side of the second grounding electrode, and the main electrode, the auxiliary electrode and the annular grounding electrode are electrically connected with the oscillating circuit to form a capacitance three-point oscillating circuit. Therefore, by arranging the grounding electrodes around the main electrode and the auxiliary electrode, the ground coupling capacitance of the main electrode and the auxiliary electrode is remarkably increased, the influence of surrounding metal on the numerical value of the ground coupling capacitance of the main electrode and the auxiliary electrode is reduced, and the shielding performance of the surrounding metal is improved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a capacitive proximity sensor and an electronic device. Background Art

[0002] A proximity sensor is a device that can sense the proximity of an object. It can replace contact detection methods such as switches. It records the movement and existence information of the object without touching the object to be detected and converts it into an electrical signal, usually a switch signal. Therefore, proximity sensors are usually called "proximity switches". Because it can detect in a non-contact manner and will not wear or damage the object to be detected, it is widely used in industrial production lines.

[0003] The proximity sensor generally needs to be installed on a metal mounting bracket (such as a nut on the bracket). There are two installation methods: non-flush installation and flush installation. The non-flush installation method is that the head of the proximity sensor is not flush with the metal mounting bracket, and the flush installation method is that the head of the proximity sensor is flush with the metal mounting bracket.

[0004] For capacitive proximity sensors, metal around the sensor (hereinafter referred to as "surrounding metal", such as mounting nuts) may cause the sensor to malfunction or reduce its sensitivity. Therefore, in order to reduce the possibility of this happening, non-flush mounting is generally used. On the other hand, when flush mounting is used, in order to eliminate / reduce the impact of surrounding metal on the sensor, a shielding electrode is usually added around the detection electrode.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Utility Model Content

[0006] The inventors found that since the surrounding metal has a significant impact on the capacitance value of the coupling capacitance between the main and auxiliary electrodes of the detection electrode and the ground, simply adding a shielding electrode around the detection electrode is difficult to eliminate the impact of the surrounding metal on sensor detection during flush installation, and the shielding effect is poor.

[0007] In order to solve at least one of the above problems or other similar problems, the embodiments of the present application provide a capacitive proximity sensor and an electronic device to improve the shielding performance against surrounding metals.

[0008] A first aspect of an embodiment of the present application provides a capacitive proximity sensor, which includes a detection electrode and an oscillation circuit electrically connected to the detection electrode, wherein the detection electrode includes a main electrode, a first ground electrode surrounding the radial outside of the main electrode and insulated from the main electrode, an auxiliary electrode arranged opposite to the main electrode, a second ground electrode surrounding the radial outside of the auxiliary electrode and insulated from the auxiliary electrode, and an annular ground electrode surrounding the radial outside of the first ground electrode and the second ground electrode, and the main electrode, the auxiliary electrode and the annular ground electrode are electrically connected to the oscillation circuit to form a capacitive three-point oscillation circuit.

[0009] In addition, optionally, the detection electrode further includes an insulating printed circuit board, the main electrode and the first ground electrode are arranged on a first surface of the insulating printed circuit board, and the auxiliary electrode and the second ground electrode are arranged on a second surface of the insulating printed circuit board opposite to the first surface.

[0010] In addition, optionally, the annular ground electrode extends axially.

[0011] The detection electrode is disposed radially inward of the annular ground electrode and covers an opening on one axial side of the annular ground electrode.

[0012] In addition, optionally, the main electrode is circular, and the first grounding electrode is annular and concentric with the main electrode;

[0013] The auxiliary electrode is circular, and the second ground electrode is annular and concentric with the auxiliary electrode.

[0014] In addition, optionally, the diameter of the main electrode is equal to the diameter of the auxiliary electrode.

[0015] The radial width of the first ground electrode is equal to the radial width of the second ground electrode,

[0016] The radial width of the first ground electrode is 5% to 25% of the diameter of the main electrode.

[0017] In addition, optionally, the diameter of the main electrode is 8 mm to 12 mm.

[0018] An inner diameter of the first ground electrode is 9 mm to 13 mm, and an outer diameter of the first ground electrode is 11 mm to 15 mm.

[0019] In addition, optionally, the axial dimension of the annular ground electrode is 5 to 20 times the thickness of the insulating printed circuit board.

[0020] In addition, optionally, the thickness of the insulating printed circuit board is 0.5 mm to 2 mm.

[0021] The axial dimension of the annular ground electrode is 6 mm to 18 mm.

[0022] In addition, optionally, the capacitive proximity sensor is installed in a flush installation manner.

[0023] In addition, optionally, the main electrode and the first ground electrode form a first coupling capacitor,

[0024] The main electrode and the second ground electrode form a second coupling capacitor,

[0025] The main electrode and the annular ground electrode form a third coupling capacitor,

[0026] The sum of the first coupling capacitance and the second coupling capacitance is greater than the third coupling capacitance.

[0027] In addition, optionally, the auxiliary electrode and the first ground electrode form a fourth coupling capacitor,

[0028] The auxiliary electrode and the second ground electrode form a fifth coupling capacitor,

[0029] The auxiliary electrode and the annular grounding electrode form a sixth coupling capacitor,

[0030] The sum of the fourth coupling capacitance and the fifth coupling capacitance is greater than the sixth coupling capacitance.

[0031] A second aspect of the embodiments of the present application provides an electronic device, which includes the capacitive proximity sensor described in the embodiments of the first aspect.

[0032] One of the beneficial effects of the embodiments of the present application is that by arranging the first and second grounding electrodes around the main electrode and the auxiliary electrode, the coupling capacitance between the main and auxiliary electrodes and the ground is significantly increased. At the same time, the presence of the annular grounding electrode reduces the influence of the surrounding metal on the value of the coupling capacitance between the main and auxiliary electrodes and the ground, thereby improving the shielding performance of the surrounding metal.

[0033] With reference to the following description and accompanying drawings, the specific embodiments of the present application are disclosed in detail, indicating the way in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope. Within the scope of the terms of the appended claims, the embodiments of the present application include many changes, modifications and equivalents.

[0034] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0035] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The elements and features described in one figure or one implementation of the present application embodiment may be combined with the elements and features shown in one or more other figures or implementations. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one implementation.

[0037] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] In the attached picture:

[0039] Figure 1 is a schematic diagram of a capacitive proximity sensor according to an embodiment of the present application viewed from one direction;

[0040] Figure 2 is a schematic diagram of the capacitive proximity sensor according to an embodiment of the present application viewed from another direction;

[0041] Figure 3 is a schematic diagram of a circuit structure formed by using a capacitive proximity sensor according to an embodiment of the present application;

[0042] Figure 4 It is a schematic diagram of the detection electrode viewed from the main electrode side;

[0043] Figure 5 It is a schematic diagram of observing the detection electrode from the auxiliary electrode side;

[0044] Figures 6 to 8 is a schematic diagram of simulating various capacitance values ​​of the capacitive proximity sensor of an embodiment of the present application in three situations: no surrounding metal, flush installation with surrounding metal, and non-flush installation with surrounding metal;

[0045] Figures 9 to 11 It is a schematic diagram of simulating various capacitance values ​​of the capacitive proximity sensor in the prior art in three situations: no surrounding metal, flush installation of surrounding metal, and non-flush installation of surrounding metal.

[0046] Tag Name

[0047] 1: Capacitive proximity sensor;

[0048] 10: Main electrode;

[0049] 11: first ground electrode;

[0050] 2: Detection electrode;

[0051] 20: auxiliary electrode;

[0052] 22: second ground electrode;

[0053] 23: Insulated printed circuit board;

[0054] 231: first surface;

[0055] 232: second surface;

[0056] 3: Oscillation circuit;

[0057] 30: Ring ground electrode;

[0058] 40: Capacitor three-point oscillation circuit;

[0059] 50: detection and low-pass filter circuit;

[0060] 60: sampling processing circuit;

[0061] 70: power supply and output circuit;

[0062] OO: Center axis. DETAILED DESCRIPTION

[0063] With reference to the accompanying drawings, the above and other features of the present application will become apparent through the following description. In the specification and the accompanying drawings, specific embodiments of the present application are specifically disclosed, which show some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the attached claims.

[0064] In the embodiments of the present application, the terms "first", "second", etc. are used to distinguish different elements in terms of title, but do not indicate the spatial arrangement or temporal order of these elements, etc., and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising", "including", "having", etc. refer to the presence of the stated features, elements, components or components, but do not exclude the presence or addition of one or more other features, elements, components or components.

[0065] In the embodiments of the present application, the singular forms "a", "the", etc. may include plural forms and should be broadly understood as "a kind" or "a type" rather than being limited to the meaning of "one"; in addition, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. In addition, the term "according to" should be understood as "at least in part according to...", and the term "based on" should be understood as "at least in part based on...", unless the context clearly indicates otherwise.

[0066] In addition, for the sake of convenience, the direction perpendicular to the detection electrode is called the "axial direction", the radial direction centered on the central axis OO of the detection electrode is called the "radial direction", the direction away from the central axis along the "radial direction" is called the "radial outer side", and the direction approaching the central axis along the "radial direction" is called the "radial inner side".

[0067] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0068] The present application embodiment provides a capacitive proximity sensor, Figure 1 is a schematic diagram of a capacitive proximity sensor according to an embodiment of the present application viewed from one direction, Figure 2 is a schematic diagram of the capacitive proximity sensor of the embodiment of the present application viewed from another direction, Figure 3 It is a schematic diagram of a circuit structure formed by using the capacitive proximity sensor of an embodiment of the present application.

[0069] like Figure 1 As shown, the capacitive proximity sensor 1 includes a detection electrode 2 and an oscillation circuit 3 ( Figure 1 The detection electrode 2 includes a main electrode 10 and a first grounding electrode 11, and the first grounding electrode 11 surrounds the radial outer side of the main electrode 10 and is insulated from the main electrode 10; Figure 2 As shown, the detection electrode 2 further includes an auxiliary electrode 20 and a second grounding electrode 22, the second grounding electrode 22 surrounds the radial outer side of the auxiliary electrode 20 and is insulated from the auxiliary electrode 20, and the auxiliary electrode 20 is arranged opposite to the main electrode 10. In addition, the detection electrode 2 further includes an annular grounding electrode 30 surrounding the radial outer side of the first grounding electrode 11 and the second grounding electrode 22.

[0070] like Figure 3 As shown, the main electrode 10, the auxiliary electrode 20 and the annular ground electrode 30 are electrically connected to the oscillation circuit 3 to form a capacitive three-point oscillation circuit 40. Among them, the capacitor C1 is the reference capacitor, which is mainly composed of the coupling capacitance of the auxiliary electrode 20 to the ground, and the capacitor C2 is the measured capacitance, which is mainly composed of the coupling capacitance of the main electrode 10 to the ground and the capacitance between the main electrode 10 and the subject. When the subject approaches, the capacitance between the main electrode 10 and the subject increases, that is, the capacitance C2 increases, and when the capacitance C2 is greater than the capacitance C1, the circuit starts to oscillate.

[0071] In addition, if Figure 3 As shown, the capacitive proximity sensor 1 may also include a detection and low-pass filtering circuit 50, a sampling processing circuit 60, and a power supply and output circuit 70. The detection and low-pass filtering circuit 50 and the sampling processing circuit 60 process the oscillation signal, and the power supply and output circuit 70 provides power for each circuit and outputs the signal processed by the sampling processing circuit 60. The embodiment of the present application does not limit the implementation of the detection and low-pass filtering circuit 50, the sampling processing circuit 60, the power supply and output circuit 70, and reference may be made to the relevant technology. In addition, Figure 3 The sampling processing circuit 60 is illustrated by taking an analog-to-digital converter (ADC) and a microprocessor (MPU) as examples, but the embodiments of the present application are not limited thereto.

[0072] In the embodiment of the present application, in the absence of surrounding metal, the coupling capacitance C of the main electrode 10 to the ground is 10 and the coupling capacitance C of the auxiliary electrode 20 to the ground 20 It can be expressed as:

[0073]

[0074] Among them, C 11 The capacitance between the main electrode 10 and the first ground electrode 11 (which may be referred to as a “first coupling capacitance”), C 12 The capacitance between the main electrode 10 and the second ground electrode 22 (which may be referred to as “second coupling capacitance”), C 13 The capacitance between the main electrode 10 and the annular ground electrode 30 (which may be referred to as the “third coupling capacitance”); C 21 is the capacitance between the auxiliary electrode 20 and the first ground electrode 11 (which may be referred to as the “fourth coupling capacitance”), C 22 is the capacitance between the auxiliary electrode 20 and the second ground electrode 22 (which may be referred to as the “fifth coupling capacitance”), C 23 It is the capacitance between the auxiliary electrode 20 and the annular ground electrode 30 (may be called “sixth coupling capacitance”).

[0075] Due to C 11 +C 12 >>C 13 , C 21 +C 22 >>C 23 Therefore, compared with the case where the first grounding electrode 11 and the second grounding electrode 22 are not provided, the change in the coupling capacitance of the surrounding metal to the main electrode 10 to the ground outside the annular grounding electrode 30 is greater than the coupling capacitance C of the main electrode 10 to the ground. 10The change in the coupling capacitance of the surrounding metal to the auxiliary electrode 20 to the ground outside the annular grounding electrode 30 is small and can be ignored. 20 It is also very small and can be ignored. That is to say, since the first grounding electrode and the second grounding electrode are used to significantly increase the coupling capacitance between the main and auxiliary electrodes and the ground, even if there is a metal object other than the object to be detected on the side of the detection electrode, the influence of the metal object on the value of the coupling capacitance between the main and auxiliary electrodes and the ground is small and can be ignored, thereby improving the shielding performance against the surrounding metal.

[0076] In this way, by arranging the first and second grounding electrodes around the main electrode and the auxiliary electrode, the coupling capacitance between the main and auxiliary electrodes and the ground is significantly increased. At the same time, the annular grounding electrode reduces the influence of the surrounding metal on the value of the coupling capacitance between the main and auxiliary electrodes and the ground, thereby improving the shielding performance of the surrounding metal.

[0077] Figure 4 This is a schematic diagram of the detection electrode viewed from the main electrode side. Figure 5 This is a schematic diagram of the detection electrode viewed from the auxiliary electrode side.

[0078] like Figure 4 and Figure 5 As shown, the detection electrode 2 also includes an insulating printed circuit board 23, such as Figure 4 As shown, the main electrode 10 and the first ground electrode 11 are arranged on the first surface 231 of the insulating printed circuit board 23. Figure 5 As shown, the auxiliary electrode 20 and the second ground electrode 22 are arranged on the second surface 232 of the insulating printed circuit board 23, and the first surface 231 and the second surface 232 are opposite in the axial direction. Optionally, the main electrode 10, the first ground electrode 11, the auxiliary electrode 20, and the second ground electrode 22 can be formed on the insulating printed circuit board 23 by a copper cladding process, which is not limited in the embodiment of the present application.

[0079] In some embodiments, Figure 4 As shown, the main electrode 10 is circular, and the first ground electrode 11 is annular and concentric with the main electrode 10; Figure 5As shown, the auxiliary electrode 20 is circular, and the second grounding electrode 22 is annular and concentric with the auxiliary electrode 20. In addition, optionally, the diameter D1 of the main electrode 10 may be equal to the diameter D2 of the auxiliary electrode 20, the radial width W1 of the first grounding electrode 11 may be equal to the radial width W2 of the second grounding electrode, and the radial width W1 of the first grounding electrode 11 (or the radial width W2 of the second grounding electrode) may be 5% to 25% of the diameter D1 of the main electrode 10 (or the diameter D2 of the auxiliary electrode 20). For example, the diameter D1 of the main electrode 10 or the diameter D2 of the auxiliary electrode 20 is 8 mm to 12 mm, such as 10 mm, the radial width W1 of the first ground electrode 11 (or the radial width W2 of the second ground electrode) is 0.4 mm to 3 mm, such as 2 mm, for example, the inner diameter r1 of the first ground electrode 11 (or the inner diameter r2 of the second ground electrode) is 9 mm to 13 mm, such as 11 mm, and the outer diameter R1 of the first ground electrode 11 (or the outer diameter R2 of the second ground electrode) is 11 mm to 15 mm, such as 13 mm. In this way, it is possible to ensure that the main electrode 10 has a large area to maximize the sensitivity, and to ensure that the capacitance between the first ground electrode 11, the second ground electrode 22 and the main and auxiliary electrodes is large to improve the shielding performance of the surrounding metal.

[0080] In addition, optional, such as Figure 1 and Figure 2 As shown, the annular ground electrode 30 extends in the axial direction, and the detection electrode 2 is arranged radially inside the annular ground electrode 30 and covers the opening on one axial side of the annular ground electrode 30. Thus, the annular ground electrode 30 is used to electromagnetically shield the detection electrode 2.

[0081] In addition, optionally, the axial dimension (ie, height H) of the annular ground electrode 30 may be 0.75 to 1.5 times the diameter D1 of the main electrode 10. For example, the diameter D1 of the main electrode 10 is 8 mm to 12 mm, such as 10 mm, and the axial dimension of the annular ground electrode is 6 mm to 18 mm, such as 10 mm.

[0082] In addition, optionally, the axial dimension (i.e., height H) of the annular ground electrode may be 5 to 20 times the thickness of the insulating printed circuit board 23. For example, the thickness of the insulating printed circuit board 23 may be 0.5 mm to 2 mm, such as 1 mm, and the axial dimension of the annular ground electrode is 6 mm to 18 mm, such as 10 mm.

[0083] In addition, the capacitive proximity sensor 1 according to the embodiment of the present application may be installed in a flush installation manner or in a non-flush installation manner.

[0084] Figures 6 to 8is a schematic diagram of simulating various capacitance values ​​of the capacitive proximity sensor of the embodiment of the present application in three situations: no surrounding metal, flush installation with surrounding metal, and non-flush installation with surrounding metal. Figures 9 to 11 It is a schematic diagram of simulating various capacitance values ​​of the capacitive proximity sensor in the prior art in three situations: no surrounding metal, flush installation of surrounding metal, and non-flush installation of surrounding metal.

[0085] like Figures 6 to 8 As shown, curve L1 represents the capacitance value of the main electrode to the ground, curve L2 represents the capacitance value of the main electrode and the auxiliary electrode, curve L3 represents the capacitance value of the main electrode to the object under test (also called "target"), and curve L4 represents the capacitance value of the main electrode to the mounting fixture. Figures 6 to 8 As shown, in the capacitance proximity sensor of the embodiment of the present application, no matter in which case, when the subject approaches, the value change of the coupling capacitance of each structure of the detection electrode (ie, curves L1, L2, L4) is small.

[0086] like Figures 9 to 11 As shown, curve M1 represents the capacitance value between the main electrode and the auxiliary electrode, curve M2 represents the capacitance value between the main electrode and the ground, and curve M3 represents the capacitance value between the auxiliary electrode and the ground. Figures 9 to 11 As shown in the dotted circle in the figure, in the capacitive proximity sensor of the prior art, the Fig. 9 as shown) and non-flush mounted surrounding metal ( Fig.11 as shown) compared to flush mounting with surrounding metal (e.g. nuts, Fig.10 After that, the capacitance value of the main electrode to the ground changes significantly at a close distance.

[0087] It can be seen that even in the case of flush installation of the surrounding metal, the capacitive proximity sensor of the embodiment of the present application significantly increases the coupling capacitance of the main and auxiliary electrodes to the ground due to the provision of the grounding electrode around the main electrode and the auxiliary electrode. At the same time, due to the presence of the annular grounding electrode, the influence of the surrounding metal on the value of the coupling capacitance of the main and auxiliary electrodes to the ground can be reduced, thereby improving the shielding performance of the surrounding metal.

[0088] According to the capacitive proximity sensor provided in the embodiment of the present application, by arranging a grounding electrode around the main electrode and the auxiliary electrode, the coupling capacitance between the main and auxiliary electrodes and the ground is significantly increased. At the same time, the presence of the annular grounding electrode reduces the influence of the surrounding metal on the value of the coupling capacitance between the main and auxiliary electrodes and the ground, thereby improving the shielding performance against the surrounding metal.

[0089] An embodiment of the present application further provides an electronic device, which includes the capacitive proximity sensor described in any of the aforementioned embodiments. Since the structure of the capacitive proximity sensor has been described in detail before, its content is incorporated here and the description is omitted here.

[0090] In addition, the electronic device described in the embodiment of the present application may be an electronic switch, a rangefinder, etc., and the embodiment of the present application does not limit this.

[0091] It is worth noting that only the components or modules related to the present application are described above, but the present application is not limited thereto. The capacitive proximity sensor and electronic device of the present application embodiment may also include other components or modules, and the specific contents of these components or modules may refer to the relevant technology.

Claims

1. A capacitive proximity sensor, characterized in that: The capacitive proximity sensor includes a detection electrode and an oscillation circuit electrically connected to the detection electrode, the detection electrode includes a main electrode, a first ground electrode surrounding the radial outside of the main electrode and insulated from the main electrode, an auxiliary electrode arranged opposite to the main electrode, a second ground electrode surrounding the radial outside of the auxiliary electrode and insulated from the auxiliary electrode, and an annular ground electrode surrounding the radial outside of the first ground electrode and the second ground electrode, the main electrode, the auxiliary electrode and the annular ground electrode are electrically connected to the oscillation circuit to form a capacitive three-point oscillation circuit.

2. The capacitive proximity sensor according to claim 1, characterized in that: The detection electrode further includes an insulating printed circuit board, the main electrode and the first ground electrode are arranged on a first surface of the insulating printed circuit board, and the auxiliary electrode and the second ground electrode are arranged on a second surface of the insulating printed circuit board opposite to the first surface.

3. The capacitive proximity sensor according to claim 2, characterized in that: The annular ground electrode extends axially, The detection electrode is disposed radially inward of the annular ground electrode and covers an opening on one axial side of the annular ground electrode.

4. The capacitive proximity sensor according to claim 3, characterized in that: The main electrode is circular, and the first grounding electrode is annular and concentric with the main electrode; The auxiliary electrode is circular, and the second ground electrode is annular and concentric with the auxiliary electrode.

5. The capacitive proximity sensor according to claim 4, characterized in that: The diameter of the main electrode is equal to the diameter of the auxiliary electrode, The radial width of the first ground electrode is equal to the radial width of the second ground electrode, The radial width of the first ground electrode is 5% to 25% of the diameter of the main electrode.

6. The capacitive proximity sensor according to claim 5, characterized in that: The diameter of the main electrode is 8 mm to 12 mm. An inner diameter of the first ground electrode is 9 mm to 13 mm, and an outer diameter of the first ground electrode is 11 mm to 15 mm.

7. The capacitive proximity sensor according to claim 5, characterized in that: The axial dimension of the annular ground electrode is 5 to 20 times the thickness of the insulating printed circuit board.

8. The capacitive proximity sensor according to claim 7, characterized in that: The thickness of the insulating printed circuit board is 0.5 mm to 2 mm, The axial dimension of the annular ground electrode is 6 mm to 18 mm.

9. The capacitive proximity sensor according to claim 1, characterized in that: The capacitive proximity sensor is installed in a flush mounting manner.

10. An electronic device, characterized in that: The electronic device comprises the capacitive proximity sensor according to any one of claims 1 to 9.

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