Multi-channel deep meshing comb tooth type electrode structure and capacitive sensor

Abstract

The invention discloses a multi-channel deep meshing comb tooth type electrode structure and a capacitive sensor, and belongs to the field of proximity sensors. The electrode structure comprises an excitation electrode, an induction electrode and a shielding electrode, wherein the shielding electrode surrounds the excitation electrode and the induction electrode; the exciting electrode comprises exciting electrode trunks and exciting electrode extension parts which are arranged in pairs and are centrosymmetric, and the same exciting electrode extension part is connected with an exciting electrode comb tooth part; the induction electrode comprises induction electrode extension parts which are arranged in pairs and are centrosymmetric, and the same induction electrode extension part is connected with an induction electrode comb tooth part; and the comb tooth parts of the excitation electrodes and the comb tooth parts of the adjacent induction electrodes are arranged in parallel and in a staggered manner. For small target detection, sensitivity difference is caused by non-uniform space electric fields of electrodes, and distance errors are caused by different intersection points; meanwhile, according to the multi-electrode design, multi-channel sensor fusion is adopted, and the distance fixing precision is further improved.

Description

Technical Field

[0001] The present invention relates to the field of proximity sensors, and particularly to a multi-channel deeply meshed comb-shaped electrode structure and a capacitive sensor. Background Art

[0002] In the field of modern electronic technology, capacitive sensors play an important role in many application scenarios due to their unique advantages, especially in target detection and positioning. With the continuous progress of technology, the requirements for the performance of capacitive sensors are also increasing day by day. Among them, the uniformity of the sensitive field distribution has become a key factor affecting the detection accuracy and positioning accuracy of capacitive sensors.

[0003] The electrode structures of traditional capacitive sensors are mostly regular polygons such as circles, triangles, rectangles, etc. These shaped electrodes are relatively simple in design and manufacturing, but in practical applications, the distribution of their field strength sensitive areas is not uniform enough. This non-uniformity causes significant differences in detection sensitivity when the intersection points of the target and the sensor in space are different, thereby affecting the detection accuracy and positioning accuracy of the capacitive sensor and limiting its performance in high-precision applications. Therefore, problems such as non-uniform spatial electric field distribution, inconsistent detection sensitivity, and different sensor space intersection points lead to large errors in the detection and positioning of sensors with traditional shaped electrode structures, especially in the detection of small targets.

[0004] In addition, in recent years, multi-channel capacitive sensor technology has gradually emerged. By the collaborative work of multiple channels, the target can be detected from multiple angles and directions, and then the data of multiple channels are fused and analyzed using signal processing algorithms, which helps to further improve the accuracy of target detection and positioning accuracy of capacitive sensors. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention proposes a multi-channel deeply meshed comb-shaped electrode structure and a capacitive sensor.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] In the first aspect of the present invention, it relates to a capacitive sensor electrode structure, including: an excitation electrode, a sensing electrode, and a shielding electrode,

[0008] The shielding electrode surrounds the excitation electrode and the sensing electrode;

[0009] The excitation electrode includes excitation electrode main trunks arranged in pairs and centrosymmetrically, and excitation electrode extension parts connected to the ends of the excitation electrode main trunks. A plurality of excitation electrode comb teeth parts are connected to the same excitation electrode extension part;

[0010] The induction electrode includes induction electrode extension parts arranged in pairs and centrosymmetrically, and a plurality of induction electrode comb teeth parts are connected to the same induction electrode extension part;

[0011] The excitation electrode comb teeth parts and the adjacent induction electrode comb teeth parts are arranged parallel to and staggered with each other; both the excitation electrode comb teeth parts and the induction electrode comb teeth parts extend spirally, and the spiral extension directions are opposite.

[0012] Optionally, both the excitation electrode comb teeth parts and the induction electrode comb teeth parts are V-shaped. One side of the induction electrode comb teeth part and the excitation electrode comb teeth part is parallel to the central part of the excitation electrode, and the other side of the induction electrode comb teeth part and the excitation electrode comb teeth part is parallel to the central part of the adjacent excitation electrode.

[0013] Optionally, any excitation electrode main body is parallel to the adjacent induction electrode comb teeth part and the excitation electrode comb teeth part, and the distance between each group of adjacent and parallel excitation electrode comb teeth parts and induction electrode comb teeth parts is equal.

[0014] Optionally, an arc transition is adopted between the induction electrode extension part and the induction electrode comb teeth part, and between the excitation electrode extension part and the excitation electrode comb teeth part and the excitation electrode main body.

[0015] Optionally, the shielding electrode is set as an N-sided polygon with opposite sides parallel to each other, and the number of the excitation electrode main body, the excitation electrode extension part and the induction electrode extension part is N, and N is an even number.

[0016] Optionally, both the excitation electrode extension part and the induction electrode extension part are parallel to the sides of the adjacent shielding electrode.

[0017] Optionally, N = 4, and the 4 excitation electrode main bodies cross to form an X shape.

[0018] Optionally, the shielding electrode is rectangular.

[0019] Optionally, three excitation electrode comb teeth parts and induction electrode comb teeth parts are respectively provided on the same excitation electrode extension part and the same induction electrode extension part.

[0020] In the second aspect of the present invention, a capacitance sensor is involved, including the capacitance sensor electrode structure described above.

[0021] The beneficial effects of the present invention:

[0022] The present invention proposes a multi-channel deep-meshing comb-shaped electrode structure for enhancing the uniformity of the sensitive field distribution of a capacitive sensor. Through the collaborative work of multiple channels, this structure can achieve multi-angle and multi-directional detection of the target, thereby obtaining more comprehensive capacitance information. By innovatively optimizing the shape of the deep-meshing comb-shaped electrode, the uniformity of the field strength sensitive area of the capacitive sensor is significantly improved, which helps to improve the accuracy of target detection and the positioning accuracy. This design enhances the performance of the capacitive sensor in the detection and positioning scenarios of small targets, providing an effective solution for the technical development in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 is a detection electrode model diagram;

[0025] Figure 2 is a planar electrode capacitance equivalent model;

[0026] Figure 3 is a simulation diagram of the spatial electric field potential distribution of a traditional circular planar electrode;

[0027] Figure 4 is a simulation diagram of the spatial electric field potential distribution of a four-channel deep-meshing comb electrode.

[0028] The corresponding components in the figure are:

[0029] 1. PCB substrate; 2. Main body of the excitation electrode; 3. Extension part of the excitation electrode; 4. Comb part of the excitation electrode; 5. Extension part of the induction electrode; 6. Comb part of the induction electrode; 7. Shielding electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figure 1 shown, a four-channel deep-meshing comb-shaped electrode structure in this embodiment includes a printed circuit board (PCB) substrate with a size of 200mm * 100mm, and one excitation electrode, four induction electrodes, and one shielding electrode 7 arranged on one side of the PCB substrate 1.

[0032] Generally speaking, the excitation electrode and the induction electrode are symmetrically distributed about the geometric center of the PCB substrate 1 and are arranged alternately in a triangular spiral shape. Specifically, the excitation electrode extends spirally clockwise, and the induction electrode extends spirally counterclockwise, and the two together form a deeply meshed comb-like cross structure.

[0033] Specifically, in this embodiment, the PCB substrate 1 is rectangular. Among the four induction electrodes, a pair of induction electrodes located on the opposite sides of the PCB substrate 1 are symmetrically distributed about the center of the PCB substrate 1. The excitation electrode in this embodiment is generally in an X shape. For the convenience of description, the X-shaped parts of the excitation electrode can be regarded as four excitation electrode main trunks 2. Similarly, any one excitation electrode main trunk 2 and another excitation electrode main trunk 2 located on the opposite side of the PCB substrate 1 are symmetrically distributed about the geometric center of the PCB substrate 1.

[0034] The parts at the ends of the X-shaped excitation electrode main trunks 2 can be regarded as excitation electrode extension parts 3, and the excitation electrode comb parts 4 are provided on the excitation electrode extension parts 3. Similarly, the induction electrode can also be divided into an induction electrode extension part 5 and an induction electrode comb part 6.

[0035] There is a pair of induction electrode comb parts 6 and excitation electrode comb parts 4 between two adjacent excitation electrode main trunks 2, and this pair of induction electrode comb parts 6 and excitation electrode comb parts 4 are arranged alternately with each other to form a deeply meshed comb structure. The spacing between adjacent induction electrode comb parts 6 and excitation electrode comb parts 4 can be set to be equal. More specifically, both the induction electrode comb part 6 and the excitation electrode comb part 4 are V-shaped, and the two sides of the V shape are respectively parallel to the adjacent excitation electrode main trunks 2.

[0036] Both the excitation electrode extension part 3 and the induction electrode extension part 5 are parallel to the edges of the adjacent shielding electrode 7.

[0037] By dividing the four excitation electrode main trunks 2, it can be regarded that four functional units or four channels with this structure are formed on the PCB substrate 1. The four channels can be simplified into four independent planar capacitive sensors, and the capacitance values between them are represented by C12, C13, C14, and C15 respectively. The equivalent capacitance diagram is as Figure 2 shown. By simulating the traditional circular electrode as Figure 3 shown and the electrode structure of the present invention as Figure 4 shown through the COMSOL finite element simulation software, it can be clearly found that the electrode structure of the present invention significantly improves the sensitive field distribution of the spatial electric field, and the sensitive field distribution is more uniform. In addition, through the simulation of the COMSOL finite element simulation software, the electrode size-related parameters can also be determined, which provides a guarantee for better implementation effects.

[0038] The triangular spiral corner region of the excitation electrode and the induction electrode adopts an arc-shaped structure design to form an obtuse transition, preventing excessive concentration of the electric field at the corner. The radius of the arc-shaped structure is 5-10 mm, which can significantly reduce the electric field concentration effect, improve the mechanical stability of the electrode, and optimize the uniformity of the sensitive field distribution, thereby improving the sensitivity of the sensor. The spacing distance d between the excitation electrode and the induction electrode remains equal in all regions of the PCB substrate 1, preferably 10-30 mm. In addition, the widths w of both the excitation electrode and the induction electrode are designed to be 20-50 mm and are consistent along the spiral extension direction. The width of the shielding electrode 7 is 10-20 mm, and it continuously surrounds the edge of the PCB substrate 1 to form a closed rectangular frame, completely surrounding the excitation electrode and the induction electrode, effectively shielding external electromagnetic interference and enhancing the electric field stability. The electrodes are all made of copper foil (with a thickness of 18-35 μm), and the electrode patterns are patterned on the surface of the PCB substrate 1 through a photolithography process, finally obtaining the planar capacitive sensor with multi-channel deeply meshed comb-shaped electrodes of the present invention.

[0039] The sensitive field of the planar capacitive sensor is a non-linear field (soft field), and the uniformity of its sensitive field distribution greatly affects the accuracy of information, and this non-uniformity is largely determined by the structural characteristics of the sensor. Through the shape design of the deeply meshed comb-shaped electrodes and the multi-channel design, not only the uniformity of the sensitive field distribution is greatly improved, but also multi-angle and multi-direction detection are realized, providing guarantee for the accuracy and precision of the information of the target to be measured. In addition, combined with relevant theories such as the electrostatic field and the edge electric field, using the COMSOL finite element simulation software, the plate structure, size parameters, shielding method, and manufacturing process are optimized, and finally the planar capacitive sensor with multi-channel deeply meshed comb-shaped electrodes in the present invention is obtained.

[0040] In summary, in the electrode structure of the above embodiment of the present invention, due to the characteristic of the uniform arrangement of multiple groups of electrodes or the functional units, the spatial electric field formed by the electrodes is also uniformly arranged. Specifically, in the embodiment of the present invention, not only the comb-shaped structure of the induction electrode and the excitation electrode contributes to the above-mentioned uniform arrangement, but also the comb-shaped part and the main trunk of the X-shaped excitation electrode follow the law of uniform equal spacing, improving the uniformity of the electric field formed by the entire electrode structure, and further improving the consistency of the detection sensitivity. Further, due to the above characteristics of the electrode structure of the present invention, the electrode structure of the present invention is particularly suitable for the detection of small targets.

[0041] On the other hand, the electrodes in the above embodiment have a structure of multi-electrode and multi-channel fusion, and the errors that may exist in a single signal source are eliminated through information fusion, and the ranging accuracy is further improved by using information redundancy.

[0042] In addition, it should be noted that in some other embodiments of the present invention, the structures of the shielding electrode 7 and the PCB substrate 1 can be set to other shapes, such as hexagons and so on. More broadly speaking, as long as a centrosymmetric electrode structure can be formed on its shape and structure, it can be applied to the present invention. In addition, the shape, number, size, etc. of the comb teeth part can also be adjusted as expected according to the needs of those skilled in the art, and are not limited to the above embodiments or the limitations of the drawings of the present invention.

[0043] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0044] The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A capacitive sensor electrode structure, characterized in that: include: Excitation electrode, sensing electrode and shielding electrode, The shielding electrode surrounds the excitation electrode and the sensing electrode; The excitation electrodes include excitation electrode trunks that are arranged in pairs and are centrally symmetrical, and excitation electrode extensions connected to the ends of the excitation electrode trunks, and a plurality of excitation electrode comb teeth are connected to the same excitation electrode extension; The sensing electrodes include sensing electrode extensions arranged in pairs and symmetrically to the center, and a plurality of sensing electrode comb-tooth portions are connected to the same sensing electrode extension; The excitation electrode comb-teeth portions and the adjacent induction electrode comb-teeth portions are parallel to each other and arranged in a staggered manner; the excitation electrode comb-teeth portions and the induction electrode comb-teeth portions are both extended in a spiral, and the directions of the spiral extension are opposite.

2. The capacitive sensor electrode structure according to claim 1, characterized in that: The excitation electrode comb-teeth portion and the sensing electrode comb-teeth portion are both V-shaped, one side of the sensing electrode comb-teeth portion and the excitation electrode comb-teeth portion is parallel to the center of the excitation electrode, and the other side of the sensing electrode comb-teeth portion and the excitation electrode comb-teeth portion is parallel to the center of the excitation electrode adjacent to the excitation electrode.

3. The capacitive sensor electrode structure according to claim 1, characterized in that: Any excitation electrode trunk is parallel to the adjacent sensing electrode comb-teeth portions and the excitation electrode comb-teeth portions, and the spacing between each group of adjacent and parallel excitation electrode comb-teeth portions and sensing electrode comb-teeth portions is equal.

4. The capacitive sensor electrode structure according to claim 1, characterized in that: Arc transitions are adopted between the sensing electrode extension part and the sensing electrode comb-tooth part, between the excitation electrode extension part and the excitation electrode comb-tooth part, and between the excitation electrode trunk.

5. The capacitive sensor electrode structure according to claim 1, characterized in that: The shielding electrode is configured as an N-sided polygon with opposite sides parallel to each other. The number of the excitation electrode trunks, excitation electrode extensions and induction electrode extensions is N, and N is an even number.

6. The capacitive sensor electrode structure according to claim 1, characterized in that: The excitation electrode extension portion and the sensing electrode extension portion are both parallel to the edges of the adjacent shielding electrodes.

7. The capacitive sensor electrode structure according to claim 5, characterized in that: N=4, and the four excitation electrode trunks are in an X shape.

8. The capacitive sensor electrode structure according to claim 5, characterized in that: The shielding electrode is rectangular.

9. The capacitive sensor electrode structure according to claim 1, characterized in that: Three excitation electrode comb-tooth portions and three induction electrode comb-tooth portions are respectively disposed on the same excitation electrode extension portion and the same induction electrode extension portion.

10. A capacitive sensor, characterized in that: The invention comprises a capacitive sensor electrode structure as described in any one of claims 1 to 9.

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