Adjustable capacitance liquid level sensor

Abstract

The invention discloses an adjustable capacitance liquid level sensor, relates to the technical field of liquid level sensors, and solves the technical problem that an adjustable capacitance liquid level sensor is urgently needed to counteract parameter deviations corresponding to different coating thicknesses due to parameter deviations existing in a coated capacitance liquid level sensor due to thickness changes. The capacitance liquid level sensor comprises a substrate, a main capacitor arranged on the substrate, at least one auxiliary capacitor and at least two bonding pads, wherein the at least one auxiliary capacitor is connected with the main capacitor in parallel through the bonding pads. According to the capacitance liquid level sensor, the multiple auxiliary capacitors are additionally arranged, the auxiliary capacitors are connected into the main capacitor of the capacitance liquid level sensor through the bonding pads, the total capacitance value of the capacitance liquid level sensor can be adjusted, parameter deviation caused by different coating thickness differences can be offset, and therefore measurement of the capacitance liquid level sensor is more accurate, and precision is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level sensors, and in particular to an adjustable capacitance liquid level sensor. Background Art

[0002] There are many existing liquid level measurement devices, and the most widely used is the capacitive level sensor. Capacitive level sensors measure liquid levels based on the principle of capacitance. They have advantages such as high sensitivity, fast response, simple structure, and strong adaptability, and are widely used in various industries.

[0003] Furthermore, in order to protect the circuit board from the corrosive effects of the liquid in the container, existing capacitive liquid level sensors place only the measuring electrode inside the container and then connect it to the detection circuit outside the container via a wire to measure the liquid level. This not only fails to prevent the wire from being damaged by the liquid in the container, causing corrosion, but also affects the lifespan of the capacitive liquid level sensor and the accuracy of liquid level detection. Therefore, in subsequent processing, the capacitive liquid level sensor is usually required to be coated with an anti-conductive film to insulate the measuring part of the capacitive liquid level sensor from the liquid. However, the coating thickness of the capacitive liquid level sensor is certain, which can easily cause parameter deviations, preventing the product parameters from meeting the required range of product performance indicators, and to a certain extent increasing production costs.

[0004] In the process of implementing the present invention, the inventors discovered that the prior art has at least the following problems:

[0005] The capacitance level sensor after coating has parameter deviation due to thickness change, and an adjustable capacitance level sensor is urgently needed to offset the parameter deviation corresponding to different coating thicknesses. Summary of the Invention

[0006] The present invention aims to provide an adjustable capacitive level sensor to address the technical problem of parameter deviations in prior art capacitive level sensors due to thickness variations after coating. This solution urgently requires an adjustable capacitive level sensor to offset these parameter deviations corresponding to varying coating thicknesses. The various technical effects achieved by the preferred technical solutions provided by the present invention are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] The present invention provides an adjustable capacitive liquid level sensor, comprising a substrate, a main capacitor arranged on the substrate, at least one auxiliary capacitor and at least two welding pads, wherein at least one of the auxiliary capacitors is connected in parallel with the main capacitor via the welding pad; the main capacitor comprises a top main electrode and a bottom main electrode, and the top main electrode and the bottom main electrode are respectively arranged on the front and back surfaces of the substrate; each of the auxiliary capacitors comprises a top auxiliary electrode and a bottom auxiliary electrode, the top main electrode is connected or disconnected with the top auxiliary electrode via one of the welding pads, and the bottom main electrode is connected or disconnected with the bottom auxiliary electrode via one of the welding pads.

[0009] Preferably, the surfaces on both sides of the substrate, the main capacitor and the corresponding parts of the auxiliary capacitor of the capacitive liquid level sensor are sprayed with a nano-coating layer.

[0010] Preferably, the capacitive liquid level sensor also includes an electrode lead-out node, and the electrode lead-out node includes a top main electrode lead-out node and a bottom main electrode lead-out node; the top main electrode is connected to the top main electrode lead-out node, and the bottom main electrode is connected to the bottom main electrode lead-out node; the top main electrode lead-out node, the bottom main electrode lead-out node, the top auxiliary electrode, each welding pad and the top main electrode are all arranged on the front side of the substrate.

[0011] Preferably, the electrode lead-out nodes further include a top-layer auxiliary electrode lead-out node and a bottom-layer auxiliary electrode lead-out node; the top-layer auxiliary electrode lead-out node includes a first top-layer auxiliary electrode lead-out node, a second top-layer auxiliary electrode lead-out node, a third top-layer auxiliary electrode lead-out node, and a fourth top-layer auxiliary electrode lead-out node; the bottom-layer auxiliary electrode lead-out nodes include a first bottom-layer auxiliary electrode lead-out node, a second bottom-layer auxiliary electrode lead-out node, a third bottom-layer auxiliary electrode lead-out node, and a fourth bottom-layer auxiliary electrode lead-out node;

[0012] The top auxiliary electrode lead-out node, the bottom auxiliary electrode lead-out node, the bottom auxiliary electrode and the bottom main electrode are all arranged on the reverse surface of the substrate.

[0013] Preferably, the top auxiliary electrode includes a first top auxiliary electrode, a second top auxiliary electrode, a third top auxiliary electrode and a fourth top auxiliary electrode;

[0014] The first top-level auxiliary electrode is connected to the first top-level auxiliary electrode lead-out node, the second top-level auxiliary electrode is connected to the second top-level auxiliary electrode lead-out node, the third top-level auxiliary electrode is connected to the third top-level auxiliary electrode lead-out node, and the fourth top-level auxiliary electrode is connected to the fourth top-level auxiliary electrode lead-out node;

[0015] The bottom auxiliary electrodes include a first bottom auxiliary electrode, a second bottom auxiliary electrode, a third bottom auxiliary electrode and a fourth bottom auxiliary electrode;

[0016] The first bottom auxiliary electrode is connected to the first bottom auxiliary electrode lead-out node, the second bottom auxiliary electrode is connected to the second bottom auxiliary electrode lead-out node, the third bottom auxiliary electrode is connected to the third bottom auxiliary electrode lead-out node, and the fourth bottom auxiliary electrode is connected to the fourth bottom auxiliary electrode lead-out node.

[0017] Preferably, the pad includes a top pad and a bottom pad, the two ends of the top pad are respectively used to connect the top main electrode lead-out node and the top auxiliary electrode lead-out node, and the two ends of the bottom pad are respectively used to connect the bottom main electrode lead-out node and the bottom auxiliary electrode lead-out node.

[0018] Preferably, the top-layer pads include a first top-layer pad, a second top-layer pad, a third top-layer pad and a fourth top-layer pad;

[0019] Two ends of the first top-layer pad are respectively used to connect the top-layer main electrode lead-out node and the first top-layer auxiliary electrode lead-out node; two ends of the second top-layer pad are respectively used to connect the top-layer main electrode lead-out node and the second top-layer auxiliary electrode lead-out node; two ends of the third top-layer pad are respectively used to connect the top-layer main electrode lead-out node and the third top-layer auxiliary electrode lead-out node; two ends of the fourth top-layer pad are respectively used to connect the top-layer main electrode lead-out node and the fourth top-layer auxiliary electrode lead-out node;

[0020] The bottom pads include a first bottom pad, a second bottom pad, a third bottom pad and a fourth bottom pad;

[0021] The two ends of the first bottom layer pad are respectively used to connect the bottom layer main electrode lead-out node and the first bottom layer auxiliary electrode lead-out node; the two ends of the second bottom layer pad are respectively used to connect the bottom layer main electrode lead-out node and the second bottom layer auxiliary electrode lead-out node; the two ends of the third bottom layer pad are respectively used to connect the bottom layer main electrode lead-out node and the third bottom layer auxiliary electrode lead-out node; the two ends of the fourth bottom layer pad are respectively used to connect the bottom layer main electrode lead-out node and the fourth bottom layer auxiliary electrode lead-out node.

[0022] Preferably, a plurality of via holes are provided on the substrate, and the pad is connected to the electrode lead-out node through the via holes.

[0023] Preferably, the capacitive liquid level sensor further includes an output electrode, which is welded on the reverse side of the substrate; the output electrode includes a first sensing electrode and a second sensing electrode, the first sensing electrode is connected to the top main electrode lead-out node, and the second sensing electrode is connected to the bottom main electrode lead-out node.

[0024] Preferably, the pad is a special-shaped pad.

[0025] Implementing one of the above technical solutions of the present invention has the following advantages or beneficial effects:

[0026] The present invention adds multiple auxiliary capacitors and connects the auxiliary capacitors to the main capacitors of the capacitive liquid level sensor through pads, so as to adjust the total capacitance value of the capacitive liquid level sensor, thereby offsetting the parameter deviation caused by differences in coating thickness, thereby making the capacitive liquid level sensor measurement more accurate and higher in precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work. In the drawings:

[0028] Figure 1 is a first structural diagram of an embodiment of the present invention;

[0029] Figure 2 is a partial schematic diagram of a first structure of an embodiment of the present invention;

[0030] Figure 3 It is a partial structural schematic diagram of the front side of an embodiment of the present invention;

[0031] Figure 4 It is a partial structural diagram of the reverse side of an embodiment of the present invention;

[0032] Figure 5 is a second structural diagram of an embodiment of the present invention;

[0033] Figure 6 1 is a circuit diagram of a capacitive liquid level sensor according to an embodiment of the present invention;

[0034] Figure 7 1 is a schematic diagram of the pad structure of an embodiment of the present invention;

[0035] Figure 8 is a schematic diagram of the first pad structure of an embodiment of the present invention;

[0036] Figure 92 is a schematic diagram of the second pad structure of an embodiment of the present invention.

[0037] In the figure: 1. main capacitor; 11. top main electrode; 12. bottom main electrode; 2. auxiliary capacitor; 21. top auxiliary electrode; 211. first top auxiliary electrode; 212. second top auxiliary electrode; 213. third top auxiliary electrode; 214. fourth top auxiliary electrode; 22. bottom auxiliary electrode; 221. first bottom auxiliary electrode; 222. second bottom auxiliary electrode; 223. third bottom auxiliary electrode; 224. fourth bottom auxiliary electrode; 3. electrode lead-out node; 31. top main electrode lead-out node; 32. bottom main electrode lead-out node; 33. top auxiliary electrode lead-out node; 331. first top auxiliary electrode lead-out node; 332. second top auxiliary electrode lead-out node; 333. third top auxiliary electrode lead-out node; 334. fourth top auxiliary electrode lead-out node; 34. bottom auxiliary electrode lead-out node; 341. first bottom auxiliary electrode lead-out node; 342. second bottom auxiliary electrode lead-out node ;343, the third bottom auxiliary electrode lead-out node;344, the fourth bottom auxiliary electrode lead-out node;4, pad;41, top pad;411, the first top pad;412, the second top pad;413, the third top pad;414, the fourth top pad;42, bottom pad;421, the first bottom pad;422, the second bottom pad;423, the third bottom pad;424, the fourth bottom pad;5, substrate;6, nano-coating layer;7, output electrode;71, the first sensing electrode;72, the second sensing electrode;401, the first pad;4011, the convex portion;402, the second pad;4021, the concave portion;403, the solder resist window. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the present invention clearer, the various exemplary embodiments to be described below will refer to the corresponding drawings, which constitute a part of the exemplary embodiments, in which various exemplary embodiments that may be used to implement the present invention are described. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation methods described in the following exemplary embodiments do not represent all implementation methods consistent with the present disclosure. It should be understood that they are only examples of processes, methods and devices that are consistent with some aspects of the present disclosure as detailed in the appended claims, and other embodiments may also be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and essence of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse" and the like indicate the orientation or positional relationship based on the figures, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the elements referred to must have a specific orientation, be constructed and operated in a specific orientation. The terms "first", "second" and the like are only used for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The term "multiple" means two or more. The terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a communication connection, a direct connection, an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0040] In order to illustrate the technical solution of the present invention, a specific embodiment is provided below, in which only the parts related to the embodiment of the present invention are shown.

[0041] Example 1:

[0042] like Figure 1-2 As shown, in order to facilitate the description of the structure of the present invention, Figure 1-2 The figure shows a first structural schematic diagram of the present invention after removing the output electrode 7. The present invention provides an adjustable capacitive liquid level sensor, comprising a substrate 5, a main capacitor 1 disposed on the substrate 5, at least one auxiliary capacitor 2, and at least two pads 4, wherein at least one auxiliary capacitor 2 is connected in parallel with the main capacitor 1 via the pads 4; the main capacitor 1 comprises a top main electrode 11 and a bottom main electrode 12, and the top main electrode 11 and the bottom main electrode 12 are disposed on the front and back surfaces of the substrate 5, respectively; each auxiliary capacitor 2 comprises a top auxiliary electrode 21 and a bottom auxiliary electrode 22, the top main electrode 11 is connected or disconnected to the top auxiliary electrode 21 via a pad 4, and the bottom main electrode 12 is connected or disconnected to the bottom auxiliary electrode 22 via a pad 4.

[0043] As an optional embodiment, the surfaces on both sides of the corresponding parts of the substrate 5, main capacitor 1 and auxiliary capacitor 2 of the capacitive liquid level sensor are sprayed with a nano-coating layer 6 to isolate the conductive liquid to be measured, avoid signal interference, and ensure the measurement accuracy of the capacitive liquid level sensor. The nano-coating layer 6 is provided on the substrate 5, main capacitor 1 and auxiliary capacitor 2, which can effectively isolate the conductive liquid to be measured from the main capacitor 1 and auxiliary capacitor 2, so that the main capacitor 1 and auxiliary capacitor 2 will not be interfered with by the conductive properties of the conductive liquid to be measured, ensuring that the capacitance value detected by the main capacitor 1 and auxiliary capacitor 2 is accurate, and further ensuring that the capacitive liquid level sensor accurately detects the level of the conductive liquid to be measured.

[0044] Specifically, the nano-coating layer 6 is processed on the substrate 5, the main capacitor 1 and the auxiliary capacitor 2 by a nano-vacuum coating process. The nano-material is used as a coating component and is coated on the surface of the substrate 5, the main capacitor 1 and the auxiliary capacitor 2 by vacuum evaporation, sputtering, chemical vapor deposition and other methods to form a uniform, dense, high-hardness, and highly corrosion-resistant thin film to isolate the main capacitor 1 and the auxiliary capacitor 2, ensuring that the main capacitor 1 and the auxiliary capacitor 2 are not interfered with by the conductive liquid, and ensuring that the capacitance liquid level sensor measures the conductive liquid to be measured with high accuracy. A nano-coating layer 6 is also provided on the corresponding position of the substrate 5 around the main capacitor 1 and the auxiliary capacitor 2. The materials used in the nano-vacuum coating include nano-insulating coatings and coupling agents. The nano-insulating material is preferably polyparaxylene, and the coupling agent is used to increase the adhesion of the nano-insulating material during coating. The thickness of the nano-coating layer 6 is adaptively set according to the insulation requirements between the main capacitor 1 and the auxiliary capacitor 2 and the conductive liquid to be measured, and the thickness of the nano-coating layer 6 needs to take into account the sensitivity requirements of the capacitance liquid level sensor.

[0045] As an optional embodiment, the substrate 5 is a PCB board, and the material of the substrate 5 is organic resin, ceramic or metal. Specifically, the material of the substrate 5 is organic resin, ceramic or metal. The material of the substrate 5 can be the above materials, but is not limited to the above materials. The specific selection of the material can be set according to actual needs. The organic resin substrate does not require high-temperature sintering, which reduces energy consumption, and has a low dielectric constant, which helps to ensure efficient operation of line signal transmission. It also has high temperature resistance, high moisture resistance and low thermal expansion coefficient; the material of the substrate 5 is preferably an FR4 substrate (glass fiber epoxy resin material). The ceramic substrate has strong mechanical stress and stable shape; it has high strength, high thermal conductivity, high insulation and good thermal cycle performance. The metal substrate has good thermal expansion, heat dissipation and dimensional stability.

[0046] like Figure 3As shown, as an optional embodiment, the capacitive liquid level sensor also includes an electrode lead-out node 3, and the electrode lead-out node 3 includes a top main electrode lead-out node 31 and a bottom main electrode lead-out node 32; the top main electrode 11 is connected to the top main electrode lead-out node 31, and the bottom main electrode 12 is connected to the bottom main electrode lead-out node 32; the top main electrode lead-out node 31, the bottom main electrode lead-out node 32, the top auxiliary electrode 21, the pad 4 and the top main electrode 11 are all arranged on the front side of the substrate 5.

[0047] like Figure 4 As shown, as an optional embodiment, the electrode lead-out node 3 also includes a top-level auxiliary electrode lead-out node 33 and a bottom-level auxiliary electrode lead-out node 34, the top-level auxiliary electrode lead-out node 33 includes a first top-level auxiliary electrode lead-out node 331, a second top-level auxiliary electrode lead-out node 332, a third top-level auxiliary electrode lead-out node 333 and a fourth top-level auxiliary electrode lead-out node 334; the bottom-level auxiliary electrode lead-out node 34 includes a first bottom-level auxiliary electrode lead-out node 341, a second bottom-level auxiliary electrode lead-out node 342, a third bottom-level auxiliary electrode lead-out node 343 and a fourth bottom-level auxiliary electrode lead-out node 344; the top-level auxiliary electrode lead-out node 33, the bottom-level auxiliary electrode lead-out node 34, the bottom-level auxiliary electrode 22 and the bottom-level main electrode 12 are all arranged on the reverse side of the substrate 5.

[0048] As an optional embodiment, the top auxiliary electrode 21 includes a first top auxiliary electrode 211, a second top auxiliary electrode 212, a third top auxiliary electrode 213 and a fourth top auxiliary electrode 214; the bottom auxiliary electrode 22 includes a first bottom auxiliary electrode 221, a second bottom auxiliary electrode 222, a third bottom auxiliary electrode 223 and a fourth bottom auxiliary electrode 224.

[0049] As an optional embodiment, the first top-level auxiliary electrode 211 is connected to the first top-level auxiliary electrode lead-out node 331, the second top-level auxiliary electrode 212 is connected to the second top-level auxiliary electrode lead-out node 332, the third top-level auxiliary electrode 213 is connected to the third top-level auxiliary electrode lead-out node 333, and the fourth top-level auxiliary electrode 214 is connected to the fourth top-level auxiliary electrode lead-out node 334; the first bottom-level auxiliary electrode 221 is connected to the first bottom-level auxiliary electrode lead-out node 341, the second bottom-level auxiliary electrode 222 is connected to the second bottom-level auxiliary electrode lead-out node 342, the third bottom-level auxiliary electrode 223 is connected to the third bottom-level auxiliary electrode lead-out node 343, and the fourth bottom-level auxiliary electrode 224 is connected to the fourth bottom-level auxiliary electrode lead-out node 344.

[0050] As an optional embodiment, the pad 4 includes a top pad 41 and a bottom pad 42. The two ends of the top pad 41 are respectively used to connect the top main electrode lead-out node 31 and the top auxiliary electrode lead-out node 33. The two ends of the bottom pad 42 (i.e., the first pad 401 and the second pad 402, and the same applies to the others) are respectively used to connect the bottom main electrode lead-out node 32 and the bottom auxiliary electrode lead-out node 34. Specifically, the top pad 41 and the bottom pad 42 are both arranged on the front surface of the substrate.

[0051] As an optional embodiment, the top pad 41 includes a first top pad 411, a second top pad 412, a third top pad 413 and a fourth top pad 414; the bottom pad 42 includes a first bottom pad 421, a second bottom pad 422, a third bottom pad 423 and a fourth bottom pad 424.

[0052] As an optional embodiment, the two ends of the first top-level pad 411 are respectively used to connect the top-level main electrode lead-out node 31 and the first top-level auxiliary electrode lead-out node 331; the two ends of the second top-level pad 412 are respectively used to connect the top-level main electrode lead-out node 31 and the second top-level auxiliary electrode lead-out node 332; the two ends of the third top-level pad 413 are respectively used to connect the top-level main electrode lead-out node 31 and the third top-level auxiliary electrode lead-out node 333; the two ends of the fourth top-level pad 414 are respectively used to connect the top-level main electrode lead-out node 31 and the fourth top-level auxiliary electrode lead-out node Point 334; the two ends of the first bottom pad 421 are respectively used to connect the bottom main electrode lead-out node 32 and the first bottom auxiliary electrode lead-out node 341; the two ends of the second bottom pad 422 are respectively used to connect the bottom main electrode lead-out node 32 and the second bottom auxiliary electrode lead-out node 342; the two ends of the third bottom pad 423 are respectively used to connect the bottom main electrode lead-out node 32 and the third bottom auxiliary electrode lead-out node 343; the two ends of the fourth bottom pad 424 are respectively used to connect the bottom main electrode lead-out node 32 and the fourth bottom auxiliary electrode lead-out node 344.

[0053] Figure 6 This is an equivalent circuit diagram of the capacitive liquid level sensor of the present invention. The capacitive liquid level sensor is provided with a main capacitor 1 (C1, equivalent to the main capacitor 1), four auxiliary capacitors 2 (C2, C3, C4, C5, equivalent to the auxiliary capacitor 2) and 8 switches (S1-S8, equivalent to the pad 4). Specifically, the main capacitor 1 is C1, and the auxiliary capacitors 2 are C2-C5 in sequence. The switches are numbered S1-S8. Among them, a switch is connected to both ends of the main capacitor 1 and the auxiliary capacitor 2. One end of each switch is connected to the main capacitor 1, and the other end is connected to the auxiliary capacitor 2.

[0054] As an optional embodiment, a plurality of via holes are provided on the substrate 5 , and the pad 4 is connected to the electrode lead-out node 3 through the via holes.

[0055] like Figure 5 FIG2 is a schematic diagram of a second structure of the present invention including an output electrode 7. As an optional embodiment, the capacitive liquid level sensor further includes an output electrode 7, which is welded to the reverse surface of the substrate 5. The output electrode 7 includes a first sensing electrode 71 and a second sensing electrode 72. The first sensing electrode 71 is connected to the top main electrode lead-out node 31, and the second sensing electrode 72 is connected to the bottom main electrode lead-out node 32.

[0056] like Figure 6-8 As shown, as an optional embodiment, the pad 4 is a special-shaped pad.

[0057] Specifically, the present invention adds multiple auxiliary electrodes and connects the auxiliary electrodes to the main electrode of the capacitive liquid level sensor through the pad 4, so as to adjust the total capacitance value of the capacitive liquid level sensor, thereby offsetting the parameter deviation caused by the difference in coating thickness of different capacitive liquid level sensors.

[0058] The implementation principle of the present invention is as follows: the top main electrode 11 and the bottom main electrode 12 are printed on the front and back surfaces of the substrate 5, respectively. Specifically, the top main electrode 11 and the top auxiliary electrode 21 are printed on the front (top) surface of the substrate 5 via traces, while the bottom main electrode 12 and the bottom auxiliary electrode 22 are printed on the back (bottom) surface of the substrate 5 via traces. Because the top main electrode 11 and the bottom main electrode 12, as well as the top auxiliary electrode 21 and the bottom auxiliary electrode 22, are isolated by the substrate 5 to form an inductive capacitor, when the capacitive liquid level sensor is placed in the conductive liquid to be measured, the capacitance between the top main electrode 11 and the bottom main electrode 12 changes. The measured capacitance value can be used to calculate the height of the conductive liquid to be measured. The surfaces on both sides of the corresponding parts of the main capacitor 1 and the auxiliary capacitor 2 on the capacitive liquid level sensor are sprayed with a nano-coating layer 6, and the nano-coating layer 6 is higher than the liquid depth of the liquid to be measured, which can effectively isolate the liquid to be measured from the top main electrode 11 and the bottom main electrode 12, so that the top main electrode 11 and the bottom main electrode 12 will not be interfered with by the conductive properties of the liquid to be measured, ensuring that the capacitance value detected by the top main electrode 11 and the bottom main electrode 12 is accurate, thereby ensuring that the capacitive liquid level sensor detects the height (i.e., depth) of the conductive liquid to be measured accurately. However, it is precisely because of the existence of the nano-coating layer 6 that the thickness of the coating cannot be completely consistent in the processing technology, and some capacitive liquid level sensors have certain parameter deviations. In order to adjust the parameters of the deviation, it is necessary to increase the auxiliary capacitor to offset the deviation value by adjusting the total capacitance of the capacitive liquid level sensor.

[0059] Among them, the top main electrode 11 and the bottom main electrode 12 form a main capacitor 1 on the substrate 5 on both sides of the substrate 5. A top auxiliary electrode 21 and a bottom auxiliary electrode 22 also form an auxiliary capacitor 2 on the substrate 5 on both sides of the substrate 5. Moreover, the present invention connects at least one top auxiliary electrode 21 and at least one bottom auxiliary electrode 22 through a pad 4 to form at least one auxiliary capacitor 2, and connects the auxiliary capacitor 2 to the main capacitor 1 in parallel with the main capacitor 1, so that the total capacitance value of the capacitive liquid level sensor can be adjusted. Correspondingly, the more auxiliary capacitors 2 are connected, the greater the total capacitance value; the fewer auxiliary capacitors 2 are connected, the smaller the total capacitance value. It should be noted that the adjustable capacitance value of the present invention is increased based on the initial capacitance value of the capacitive liquid level sensor after coating. The top main electrode 11 is connected or disconnected with the top auxiliary electrode 21 through a pad 4, and the bottom main electrode 12 is connected or disconnected with the bottom auxiliary electrode 22 through a pad 4, thereby forming a capacitive liquid level sensor with adjustable capacitance value.

[0060] like Figure 3 and Figure 4 As shown, four top auxiliary electrodes 21 and four bottom auxiliary electrodes 22 are provided on both sides of the substrate 5 on the capacitive liquid level sensor of the present invention. Due to different parameter deviations, the number of top auxiliary electrodes 21 and bottom auxiliary electrodes 22 connected to the capacitive liquid level sensor is also different. In this embodiment, there is no restriction on the specific number of top auxiliary electrodes 21 and bottom auxiliary electrodes 22 connected. The user can choose to connect at least one auxiliary capacitor 2 (one top auxiliary electrode 21 and one bottom auxiliary electrode 22) to adjust the total capacitance value of the capacitive liquid level sensor as needed.

[0061] Among them, the capacitive liquid level sensor also includes an electrode lead-out node 3, and the electrode lead-out node 3 includes a top main electrode lead-out node 31 and a bottom main electrode lead-out node 32. The top main electrode 11 and the top main electrode lead-out node 31, and the bottom main electrode 12 and the bottom main electrode lead-out node 32 are all connected on the substrate 5 through printed lines. The top main electrode lead-out node 31, the bottom main electrode lead-out node 32 and the top main electrode 11 are arranged together on the front side (top surface) of the substrate 5. This is to facilitate the measurement of the capacitance value of the capacitive liquid level sensor through the top main electrode lead-out node 31 and the bottom main electrode lead-out node 32. That is, the top main electrode lead-out node 31 and the bottom main electrode lead-out node 32 are the measurement nodes of the capacitive liquid level sensor of the present invention, which are used to transmit the capacitance value sensed by the capacitive liquid level sensor to the upper computer device.

[0062] The electrode lead-out node 3 also includes a top auxiliary electrode lead-out node 33 and a bottom auxiliary electrode lead-out node 34. The top auxiliary electrode lead-out node 33 is connected to the top auxiliary electrode 21, and the bottom auxiliary electrode lead-out node 34 is connected to the bottom auxiliary electrode 22 on the substrate 5 through a printed line. The top auxiliary electrode lead-out node 33 and the bottom auxiliary electrode lead-out node 34 are both arranged on the reverse side (bottom side) of the substrate 5. This is to facilitate the host device to realize the connection between the auxiliary capacitor and the main capacitor through the top auxiliary electrode lead-out node 33 and the bottom auxiliary electrode lead-out node 34, and then realize the capacitance value of the capacitance liquid level sensor to be adjusted. That is, the top auxiliary electrode lead-out node 33 and the bottom auxiliary electrode lead-out node 34 are the adjustment nodes of the capacitance liquid level sensor of the present invention, which are used for the host device to adjust the capacitance value sensed by the capacitance liquid level sensor. For example, the host device accesses a top auxiliary electrode 21 and a bottom auxiliary electrode 22 through the top auxiliary electrode lead-out node 33 and the bottom auxiliary electrode lead-out node 34, and can form an auxiliary capacitor 2. The auxiliary capacitor 2 is connected in parallel with the main capacitor 1 , which is equivalent to increasing the total capacitance value in the circuit, that is, adjusting the initial capacitance value sensed by the capacitive liquid level sensor.

[0063] Among them, the top-level auxiliary electrode lead-out node 33 includes a first top-level auxiliary electrode lead-out node 331, a second top-level auxiliary electrode lead-out node 332, a third top-level auxiliary electrode lead-out node 333 and a fourth top-level auxiliary electrode lead-out node 334; the bottom-level auxiliary electrode lead-out node 34 includes a first bottom-level auxiliary electrode lead-out node 341, a second bottom-level auxiliary electrode lead-out node 342, a third bottom-level auxiliary electrode lead-out node 343 and a fourth bottom-level auxiliary electrode lead-out node 344.

[0064] Correspondingly, each top auxiliary electrode 21 and each bottom auxiliary electrode 22 have corresponding lead-out nodes, that is, the first top auxiliary electrode 211 and the first top auxiliary electrode lead-out node 331 are connected on the substrate 5 through a printed line, the second top auxiliary electrode 212 and the second top auxiliary electrode lead-out node 332 are connected on the substrate 5 through a printed line, the third top auxiliary electrode 213 and the third top auxiliary electrode lead-out node 333 are connected on the substrate 5 through a printed line, and the fourth top auxiliary electrode 214 and the fourth top auxiliary electrode 215 are connected on the substrate 5 through a printed line. The lead-out node 334 is connected on the substrate 5 through a printed line; the first bottom auxiliary electrode 221 is connected to the first bottom auxiliary electrode lead-out node 341 on the substrate 5 through a printed line, the second bottom auxiliary electrode 222 is connected to the second bottom auxiliary electrode lead-out node 342 on the substrate 5 through a printed line, the third bottom auxiliary electrode 223 is connected to the third bottom auxiliary electrode lead-out node 343 on the substrate 5 through a printed line, and the fourth bottom auxiliary electrode 224 is connected to the fourth bottom auxiliary electrode lead-out node 344 on the substrate 5 through a printed line.

[0065] It should be noted that the pads 4 are all disposed on the same surface (front / top) of the substrate 5, the same surface as the top-layer main electrode 11. Multiple vias are provided on the substrate 5, and the number of vias is the same as the number of auxiliary electrode lead-out nodes (top-layer auxiliary electrode lead-out node 33 and bottom-layer auxiliary electrode lead-out node 34). The pads 4 are connected to the electrode lead-out node 3 on the other side of the substrate 5 through the multiple vias.

[0066] It should be emphasized that if the top auxiliary electrode 21 or the bottom auxiliary electrode 22 is not connected to the main capacitor 1, the pad 4 corresponding to the top auxiliary electrode 21 or the bottom auxiliary electrode 22 is in a disconnected state. That is, although both ends of the pad 4 are connected to the main electrode lead-out node (top main electrode lead-out node 31 or bottom main electrode lead-out node 32) and the auxiliary electrode lead-out node (top auxiliary electrode lead-out node 33 or bottom auxiliary electrode lead-out node 34), the two ends of the pad 4 are still in a disconnected state. After the user selects the auxiliary capacitor 2 to be connected, the two pads 4 corresponding to the auxiliary capacitor 2 are soldered to achieve a hard connection between the circuits. At this point, the adjustment of the total capacitance value of the capacitive liquid level sensor can be completed.

[0067] Furthermore, the capacitance value of each of the four top auxiliary electrodes 21 or each of the four bottom auxiliary electrodes 22 is in a step-by-step increasing relationship, which can provide more options for increasing the total capacitance value.

[0068] like Figure 5 As shown, the capacitive liquid level sensor also includes an output electrode 7, which is welded on the reverse side of the substrate; the output electrode 7 includes a first sensing electrode 71 and a second sensing electrode 72, the first sensing electrode 71 is connected to the top main electrode lead-out node 31, and the second sensing electrode 72 is connected to the bottom main electrode lead-out node 32. If the user selects a specific auxiliary capacitor 2 to be connected, and solders the two pads 4 corresponding to the auxiliary capacitor 2 with solder, a hard connection between the circuits is achieved. At this time, the output electrode 7 can be welded on the reverse side of the substrate 5, and the upper computer device can connect the first sensing electrode 71 and the second sensing electrode 72 on the output electrode 7 to the corresponding connected top main electrode lead-out node 31 and the bottom main electrode lead-out node 32, and then obtain the capacitance value sensed by the main capacitor and the auxiliary capacitor of the capacitive liquid level sensor through the top main electrode lead-out node 31 and the bottom main electrode lead-out node 32.

[0069] It should be noted that since the output electrode 7 is covered above the top auxiliary electrode lead-out node 33 and the bottom auxiliary electrode lead-out node 34, in practice, the pad 4 and the top main electrode lead-out node 31 and the bottom main electrode lead-out node 32, as well as the top main electrode 11 and the top auxiliary electrode 21 can only be observed through the front side of the substrate 5; the nano-coating layer 6 and the bottom main electrode 12 and the bottom auxiliary electrode 22 are observed on the back side of the substrate 5.

[0070] like Figure 7-9 As shown, the pad 4 is a special-shaped pad, which is a preferred option in the embodiment of the present invention. This is to facilitate keeping the circuit between the auxiliary electrode and the main electrode in an open state when the auxiliary capacitor is not selected.

[0071] Specifically, the special-shaped pad provided by the present invention is arranged on the substrate 5 (i.e., the PCBA board) for connecting and disconnecting the corresponding circuit, and includes a first pad 401 and a second pad 402 arranged adjacent to each other at intervals; the first pad 401 and the second pad 402 are two special-shaped pads divided by a V-shaped cut in the middle of an elliptical pad. Specifically, the first pad 401 and the second pad 402 are arranged on the substrate 5 for connecting and disconnecting the corresponding circuit, and the first pad 401 and the second pad 402 are two special-shaped pads divided by a V-shaped cut in the middle of an elliptical pad. The V-shaped cut makes the adjacent side surfaces of the first pad 401 and the second pad 402 concave and convex relative surfaces, which can increase the contact area between the first pad 401 and the second pad 402. When connecting and welding the first pad 401 and the second pad 402, the solder fusion area can be increased, which facilitates the connection between the first pad 401 and the second pad 402. The V-shaped incision cuts the elliptical pad into two pads from the middle, namely the first pad 401 and the second pad 402, so that the first pad 401 and the second pad 402 form special-shaped pads. When the first pad 401 and the second pad 402 are arranged horizontally, the cut edges form a side V shape; when the first pad 401 and the second pad 402 are arranged vertically, the cut edges form a V shape. Due to the characteristics of the special-shaped pads, when the circuit on the substrate 5 needs to be open-circuited, there is usually a certain distance between the first pad 401 and the second pad 402. Since the contact area between the first pad 401 and the second pad 402 is increased, there is no need to set the first pad 401 and the second pad 402 close together, which also facilitates the connection between the first pad 401 and the second pad 402. The present invention forms a first solder pad 401 and a second solder pad 402 by dividing an elliptical solder pad from the middle, and separately arranges the first solder pad 401 and the second solder pad 402 on the PCBA board to facilitate circuit disconnection. The divided incision is V-shaped, which can increase the contact area between the first solder pad 401 and the second solder pad 402 and facilitate connection of the first solder pad 401 and the second solder pad 402.

[0072] As an optional embodiment, a convex portion 4011 is provided on the side of the first pad 401 close to the second pad 402; the convex portion 4011 has a V-shaped structure; a concave portion 4021 is provided on the side of the second pad 402 close to the first pad 401; the concave portion 4021 has a V-shaped structure; and the convex portions 4011 and the concave portions 4021 match each other. Specifically, the convex portion 4011 is provided on the side of the first pad 401 close to the second pad 402, and the edge of the convex portion 4011 has a V-shaped structure; the concave portion 4021 is provided on the side of the second pad 402 close to the first pad 401, and the edge of the concave portion 4021 has a V-shaped structure, and the sizes of the convex portions 4011 and the concave portions 4021 match each other. By setting a protrusion 4011 on the first soldering pad 401 and a recess 4021 on the second soldering pad 402, the contact area between the first soldering pad 401 and the second soldering pad 402 can be increased. When the first soldering pad 401 and the second soldering pad 402 need to be soldered, the solder fusion area can be increased, making it easier to connect the first soldering pad 401 and the second soldering pad 402, thereby forming a short circuit in the circuit on the substrate 5.

[0073] As an optional embodiment, the spacing between the first pad 401 and the second pad 402 is 6 mil. Specifically, the first pad 401 and the second pad 402 are spaced apart to facilitate the open circuit of the corresponding circuit on the substrate 5. The spacing between the first pad 401 and the second pad 402 is preferably 6 mil, and the spacing between the first pad 401 and the second pad can also be adaptively set according to actual needs. When the first pad 401 and the second pad 402 are spaced apart, the width of the first pad 401 and the second pad 402 is 1 mm, and the length of the first pad 401 and the second pad 402 (i.e., the length of the first pad 401 and the second pad 402 itself plus the size of the spacing width between the first pad 401 and the second pad 402) is 1.6 mm. The size of the first pad 401 and the second pad 402 can be arbitrarily set according to actual needs.

[0074] As an optional embodiment, the first pad 401 and the second pad 402 are both provided with solder resist windows 3 on their circumferential sides; the solder resist windows 3 match the shapes of the first pad 401 and the second pad 402. The solder resist width of the solder resist window 3 is 2 mil. Specifically, the first pad 401 and the second pad 402 are respectively provided with solder resist windows 3 on their circumferential sides, and the solder resist windows 3 prevent the solder on the first pad 401 and the second pad 402 from flowing out of the pad when welding the first pad 401 and the second pad 402. The solder resist windows 3 match the shapes of the first pad 401 and the second pad 402, ensuring that the special-shaped shape between the first pad 401 and the second pad 402 does not change, and ensuring that when welding the first pad 401 and the second pad 402, they are easily connected due to the large solder fusion area. The solder resist width of the solder resist window 3 is 2 mil, which can effectively prevent the solder from flowing out of the pad.

[0075] As an optional embodiment, a solder resist layer is provided on the solder resist window 3. Specifically, the solder resist layer has an insulating effect, preventing the circuit from oxidizing. The solder resist layer can separate the soldering portion from the non-soldering portion on the substrate 5, and the material of the solder resist layer is solder resist paint.

[0076] As an optional embodiment, the first pad 401 and the second pad 402 are soldered together, thereby forming a short circuit (i.e., the circuit is connected) in the corresponding circuit on the substrate 5; the first pad 401 and the second pad 402 are disconnected, thereby forming an open circuit (i.e., the circuit is disconnected) in the corresponding circuit on the PCBA board. Specifically, the first pad 401 and the second pad 402 are soldered together to connect the corresponding circuit on the substrate 5 to form a short circuit; the first pad 401 and the second pad 402 are set separately and not soldered together, thereby disconnecting the corresponding circuit on the substrate 5 to form an open circuit.

[0077] The embodiment is only a special example and does not represent only one way of implementing the present invention.

[0078] The foregoing is merely a preferred embodiment of the present invention. Those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the guidance of the present invention, these features and embodiments may be modified to suit specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be within the scope of the present invention.

Claims

1. An adjustable capacitive liquid level sensor, characterized in that: It comprises a substrate (5), a main capacitor (1) arranged on the substrate (5), at least one auxiliary capacitor (2) and at least two pads (4), wherein at least one auxiliary capacitor (2) is connected in parallel with the main capacitor (1) via the pad (4); The main capacitor (1) comprises a top main electrode (11) and a bottom main electrode (12), and the top main electrode (11) and the bottom main electrode (12) are respectively arranged on the front and back surfaces of the substrate (5); each of the auxiliary capacitors (2) comprises a top auxiliary electrode (21) and a bottom auxiliary electrode (22), the top main electrode (11) is connected to or disconnected from the top auxiliary electrode (21) via a pad (4), and the bottom main electrode (12) is connected to or disconnected from the bottom auxiliary electrode (22) via a pad (4).

2. The adjustable capacitive liquid level sensor according to claim 1, characterized in that: Nano-plating layers (6) are spray-coated on the surfaces of both sides of the substrate (5) of the capacitive liquid level sensor, the main capacitor (1) and the corresponding parts of the auxiliary capacitor (2).

3. The adjustable capacitive liquid level sensor according to claim 1, characterized in that: The capacitive liquid level sensor further comprises an electrode lead-out node (3), wherein the electrode lead-out node (3) comprises a top main electrode lead-out node (31) and a bottom main electrode lead-out node (32); the top main electrode (11) is connected to the top main electrode lead-out node (31), and the bottom main electrode (12) is connected to the bottom main electrode lead-out node (32); The top main electrode lead-out node (31), the bottom main electrode lead-out node (32), the top auxiliary electrode (21), each of the pads (4) and the top main electrode (11) are all arranged on the front side of the substrate (5).

4. The adjustable capacitive liquid level sensor according to claim 3, characterized in that: The electrode lead-out node (3) further comprises a top-layer auxiliary electrode lead-out node (33) and a bottom-layer auxiliary electrode lead-out node (34); The top-level auxiliary electrode lead-out node (33) includes a first top-level auxiliary electrode lead-out node (331), a second top-level auxiliary electrode lead-out node (332), a third top-level auxiliary electrode lead-out node (333) and a fourth top-level auxiliary electrode lead-out node (334); The bottom auxiliary electrode lead-out node (34) includes a first bottom auxiliary electrode lead-out node (341), a second bottom auxiliary electrode lead-out node (342), a third bottom auxiliary electrode lead-out node (343) and a fourth bottom auxiliary electrode lead-out node (344); The top auxiliary electrode lead-out node (33), the bottom auxiliary electrode lead-out node (34), the bottom auxiliary electrode (22) and the bottom main electrode (12) are all arranged on the reverse side of the substrate (5).

5. The adjustable capacitive liquid level sensor according to claim 4, characterized in that: The top auxiliary electrode (21) comprises a first top auxiliary electrode (211), a second top auxiliary electrode (212), a third top auxiliary electrode (213) and a fourth top auxiliary electrode (214); The first top-level auxiliary electrode (211) is connected to the first top-level auxiliary electrode lead-out node (331), the second top-level auxiliary electrode (212) is connected to the second top-level auxiliary electrode lead-out node (332), the third top-level auxiliary electrode (213) is connected to the third top-level auxiliary electrode lead-out node (333), and the fourth top-level auxiliary electrode (214) is connected to the fourth top-level auxiliary electrode lead-out node (334); The bottom auxiliary electrode (22) comprises a first bottom auxiliary electrode (221), a second bottom auxiliary electrode (222), a third bottom auxiliary electrode (223) and a fourth bottom auxiliary electrode (224); The first bottom auxiliary electrode (221) is connected to the first bottom auxiliary electrode lead-out node (341), the second bottom auxiliary electrode (222) is connected to the second bottom auxiliary electrode lead-out node (342), the third bottom auxiliary electrode (223) is connected to the third bottom auxiliary electrode lead-out node (343), and the fourth bottom auxiliary electrode (224) is connected to the fourth bottom auxiliary electrode lead-out node (344).

6. The adjustable capacitive liquid level sensor according to claim 4, characterized in that: The pad (4) comprises a top pad (41) and a bottom pad (42), wherein two ends of the top pad (41) are respectively used to connect a top main electrode lead-out node (31) and a top auxiliary electrode lead-out node (33), and two ends of the bottom pad (42) are respectively used to connect a bottom main electrode lead-out node (32) and a bottom auxiliary electrode lead-out node (34).

7. The adjustable capacitive liquid level sensor according to claim 6, characterized in that: The top-layer pad (41) comprises a first top-layer pad (411), a second top-layer pad (412), a third top-layer pad (413) and a fourth top-layer pad (414); The two ends of the first top-layer pad (411) are respectively used to connect the top-layer main electrode lead-out node (31) and the first top-layer auxiliary electrode lead-out node (331); the two ends of the second top-layer pad (412) are respectively used to connect the top-layer main electrode lead-out node (31) and the second top-layer auxiliary electrode lead-out node (332); the two ends of the third top-layer pad (413) are respectively used to connect the top-layer main electrode lead-out node (31) and the third top-layer auxiliary electrode lead-out node (333); the two ends of the fourth top-layer pad (414) are respectively used to connect the top-layer main electrode lead-out node (31) and the fourth top-layer auxiliary electrode lead-out node (334); The bottom layer pad (42) comprises a first bottom layer pad (421), a second bottom layer pad (422), a third bottom layer pad (423) and a fourth bottom layer pad (424); The two ends of the first bottom pad (421) are respectively used to connect the bottom main electrode lead-out node (32) and the first bottom auxiliary electrode lead-out node (341); the two ends of the second bottom pad (422) are respectively used to connect the bottom main electrode lead-out node (32) and the second bottom auxiliary electrode lead-out node (342); the two ends of the third bottom pad (423) are respectively used to connect the bottom main electrode lead-out node (32) and the third bottom auxiliary electrode lead-out node (343); and the two ends of the fourth bottom pad (424) are respectively used to connect the bottom main electrode lead-out node (32) and the fourth bottom auxiliary electrode lead-out node (344).

8. The adjustable capacitive liquid level sensor according to claim 7, characterized in that: The soldering pad (4) is a special-shaped soldering pad.

9. The adjustable capacitive liquid level sensor according to claim 7, characterized in that: The substrate (5) is provided with a plurality of via holes, and the pad (4) is connected to the electrode lead-out node (3) through the via holes.

10. The adjustable capacitive liquid level sensor according to claim 4, characterized in that: The capacitive liquid level sensor further comprises an output electrode (7), wherein the output electrode (7) is welded on the reverse side of the substrate (5); the output electrode (7) comprises a first sensing electrode (71) and a second sensing electrode (72), wherein the first sensing electrode (71) is connected to the top main electrode lead-out node (31), and the second sensing electrode (72) is connected to the bottom main electrode lead-out node (32).

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