Liquid level sensor, liquid level detection device and electronic equipment

Abstract

The utility model discloses a liquid level sensor, a liquid level detection device and electronic equipment, and belongs to the technical field of detection. The liquid level sensor comprises a circuit board and an induction piece, the induction piece is electrically connected with the circuit board, and the induction piece is used for polar plates of the capacitor; the liquid level sensor has a first direction, at least part of the induction part surrounds the periphery of the circuit board in the direction perpendicular to the first direction, a gap is formed between the induction part and the circuit board, at least part of the induction part is in a curve shape in a reference section perpendicular to the first direction, and the size of the induction part in the circumferential direction is larger than that of the circuit board. According to the liquid level sensor, the gap is formed between the induction piece and the circuit board, so that the induction piece is arranged more flexibly, the size limitation of the circuit board on the induction piece can be reduced, and compared with the situation that the induction piece is attached to the circuit board, the induction area of the induction piece can be increased, and therefore the capacitance value of the capacitor is increased; and the sensitivity of the liquid level sensor is improved.

Description

Technical Field

[0001] The present application relates to the field of detection technology, and particularly relates to a liquid level sensor, a liquid level detection device and an electronic device. Background Art

[0002] A capacitive liquid level sensor determines the change in liquid level by using the different capacitance values sensed by the liquid level sensing surface when there is liquid and when there is no liquid. In related technologies, the sensing element is usually attached to the circuit board. Due to the size limitation of the circuit board, it is difficult to arrange a sensing element with a large area on the circuit board, resulting in a small sensing area of the sensing element. The capacitance value of the capacitor formed by the sensing element as the electrode plate is also correspondingly small, and the small capacitance value is not easily detected, leading to low sensitivity of the liquid level sensor. Summary of the Utility Model

[0003] The present application provides a liquid level sensor, a liquid level detection device and an electronic device, which can solve the technical problem of low sensitivity of the liquid level sensor.

[0004] To solve the above technical problem, on the one hand, the present application provides a liquid level sensor. The liquid level sensor includes a circuit board and a sensing element. The sensing element is electrically connected to the circuit board and is used as the electrode plate of the capacitor. The liquid level sensor has a first direction, at least part of the sensing element is disposed around the outer periphery of the circuit board along a direction perpendicular to the first direction, there is a gap between the sensing element and the circuit board, in a reference cross-section perpendicular to the first direction, at least part of the sensing element is curved, and the dimension of the sensing element along the circumferential direction is larger than the dimension of the circuit board.

[0005] On the other hand, the present application provides a liquid level detection device. The liquid level detection device includes the liquid level sensor as described above and a housing. The liquid level sensor is accommodated in the housing, the distance between the outer wall of the sensing element and the inner wall of the housing is less than a preset value, and the gap between the inner wall of the housing and the liquid level sensor is filled with a filling medium.

[0006] On still another hand, the present application provides an electronic device. The electronic device includes the liquid level detection device as described above. The electronic device is provided with a liquid storage cavity, and the liquid level detection device is installed in the liquid storage cavity.

[0007] In the liquid level sensor provided by the present application, there is a gap between the sensing element and the circuit board, so that the setting of the sensing element is more flexible, and the size limitation of the circuit board on the sensing element can be reduced; and in a reference cross-section perpendicular to the first direction, at least part of the sensing element is curved, and the dimension of the sensing element along the circumferential direction is larger than the dimension of the circuit board. Compared with the case where the sensing element is attached to the circuit board, the sensing area of the sensing element can be increased, thereby increasing the capacitance value of the capacitor, which is beneficial to improving the sensitivity of the liquid level sensor. Description of the Drawings

[0008] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0009] Figure 1 It is a schematic structural diagram of an embodiment of the liquid level sensor provided by the present application;

[0010] Figure 2 It is a schematic cross-sectional structural diagram of an embodiment of the liquid level sensor provided by the present application along a perspective;

[0011] Figure 3 It is a schematic cross-sectional structural diagram of another embodiment of the liquid level sensor provided by the present application along a perspective;

[0012] Figure 4 It is a schematic cross-sectional structural diagram of yet another embodiment of the liquid level sensor provided by the present application along a perspective;

[0013] Figure 5 It is a schematic cross-sectional structural diagram of an embodiment of the circuit board provided by the present application along a perspective;

[0014] Figure 6 It is a schematic structural diagram of another embodiment of the liquid level sensor provided by the present application;

[0015] Figure 7 It is a schematic structural diagram of yet another embodiment of the liquid level sensor provided by the present application;

[0016] Figure 8 It is a schematic cross-sectional structural diagram of an embodiment of the liquid level sensor provided by the present application along another perspective;

[0017] Figure 9 It is a schematic cross-sectional structural diagram of an embodiment of the liquid level detection device provided by the present application along a perspective;

[0018] Figure 10 It is a schematic cross-sectional structural diagram of an embodiment of the electronic device provided by the present application along a perspective. Detailed implementation manners

[0019] The following will further describe the present application in detail in conjunction with the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only some embodiments of the present application rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0020] In the description of this application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined. The terms "first", "second", and "third" in the embodiments of this application are only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", and "third" may explicitly or implicitly include at least one of such features. All directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, then the directional indication also changes accordingly. The terms "comprising" and "having" and any variations thereof in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or components inherent to these processes, methods, products, or devices.

[0021] Reference to "embodiment" in this context means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0022] This application provides a liquid level sensor. Please refer to Figure 1 、 Figure 2 , the liquid level sensor 100 may include a circuit board 10 and a sensing element 20. The sensing element 20 is a conductor, and the sensing element 20 is electrically connected to the circuit board 10. The sensing element 20 is used as the electrode plate of a capacitor. The calculation formula for capacitance is: C = ε r S / 4πkd, where ε r is the relative dielectric constant, k is the electrostatic force constant, S is the electrode plate area, and d is the distance between the electrode plates. For the liquid level sensor 100, the parameters k, S, and d in the capacitor formed by the sensing element 20 are all determined values. When the liquid level sensor 100 is placed in the target liquid, the change in the liquid level of the target liquid will cause a change in the relative dielectric constant ε r , thereby causing a corresponding change in the capacitance value C. Therefore, the change in the liquid level of the target liquid can be monitored by monitoring the change in the capacitance value.

[0023] The liquid level sensor 100 has a first direction. Exemplarily, the first direction may be the length direction of the liquid level sensor 100, such as Figure 1 the Z-axis direction shown. Please refer toFigure 1 , Figure 2 , the sensing element 20 at least partially surrounds the outer periphery of the circuit board 10 along a direction perpendicular to the first direction. The sensing element 20 may be such that a part of it surrounds the outer periphery of the circuit board 10 along a direction perpendicular to the first direction. In this case, the sensing element 20 forms a partial or semi - enclosure around the circuit board 10; the sensing element 20 may also be such that all of it surrounds the outer periphery of the circuit board 10 along a direction perpendicular to the first direction. In this case, the sensing element 20 forms a full enclosure around the circuit board 10. There is a gap between the sensing element 20 and the circuit board 10. In a reference cross - section perpendicular to the first direction, at least a part of the sensing element 20 is curved, and the dimension of the sensing element 20 along the circumferential direction is greater than the dimension of the circuit board 10. The sensing element 20 may be a curved line in the form of an arc or a broken line in the reference cross - section perpendicular to the first direction. The circuit board is usually flat. When the sensing element 20 is attached to the circuit board 10, the sensing element 20 is straight in the reference cross - section perpendicular to the first direction. Since the length of a curve between two points is greater than the length of a straight line, by setting at least a part of the sensing element 20 to be curved, the perimeter of the sensing element 20 can be increased, and thus the sensing area of the sensing element 20 can be increased.

[0024] In the liquid level sensor 100 provided in this application, there is a gap between the sensing element 20 and the circuit board 10, which makes the setting of the sensing element 20 more flexible and can reduce the size limitation of the circuit board 10 on the sensing element 20; and in a reference cross - section perpendicular to the first direction, at least a part of the sensing element 20 is curved, and the dimension of the sensing element 20 along the circumferential direction is greater than the dimension of the circuit board 10. Compared with the case where the sensing element 20 is attached to the circuit board 10, the sensing area of the sensing element 20 can be increased, thereby increasing the capacitance value of the capacitor, which is beneficial to improving the sensitivity of the liquid level sensor 100.

[0025] In one embodiment, as Figures 2 - 4 shown, the sensing element 20 is in the shape of a hollow cylinder, and the sensing element 20 is sleeved outside the circuit board 10. Setting the sensing element 20 to be in the shape of a hollow cylinder enables the sensing element 20 to form a semi - enclosure or a full enclosure around the circuit board 10, which can increase the sensing area of the sensing element 20, thereby improving the sensitivity of the liquid level sensor 100.

[0026] Please refer to Figure 3 , Figure 4, in one embodiment, the sensing member 20 is provided with an opening 21 that disconnects the side wall of the sensing member 20. When assembling the sensing member 20 to the circuit board 10, a force can be applied at the opening 21 of the sensing member 20 to increase the width of the opening 21 of the sensing member 20, thereby facilitating the assembly of the sensing member 20 so that the sensing member 20 is sleeved outside the circuit board 10 and forms a semi - enclosure or a full - enclosure around the circuit board 10. In addition, by setting different sizes of the opening 21, the sensing area of the sensing member 20 can be adjusted. For example, the opening 21 of the sensing member 20 can be relatively large, and the sensing member 20 is in a semi - circular ring shape. At this time, the sensing member 20 forms a semi - enclosure around the circuit board 10, as shown in Figure 4 ; or, the opening 21 of the sensing member 20 is relatively small, and the sensing member 20 is in a circular ring shape. At this time, the sensing member 20 forms a full - enclosure around the circuit board 10, as shown in Figure 3 .

[0027] In one embodiment, the shape of the sensing member 20 in a reference cross - section perpendicular to the first direction is circular, elliptical or polygonal, so that the cross - sectional shape of the sensing member 20 is relatively regular, which can facilitate the processing of the sensing member 20.

[0028] The sensing member 20 and the circuit board 10 can be connected by screws to prevent the sensing member 20 from shifting. Or, in one embodiment, as shown in Figure 5 , a limiting groove 15 is provided on the side of the circuit board 10, and the sensing member 20 is engaged in the limiting groove 15. By setting the limiting groove 15 to engage and fix the sensing member 20, since no other components are required to limit the displacement of the sensing member 20, the assembly process of the sensing member 20 can be simplified.

[0029] The sensing member 20 and the circuit board 10 can be electrically connected by wires. In one embodiment, the sensing member 20 and the circuit board 10 are connected by soldering. Setting the sensing member 20 and the circuit board 10 to be connected by soldering can not only electrically connect the sensing member 20 and the circuit board 10, but also prevent the sensing member 20 from shifting.

[0030] The number of sensing members 20 provided can be one, or multiple, such as two, three or more.

[0031] Please refer to Figure 1, in one embodiment, the circuit board 10 is elongated in the first direction, and there are two sensing elements 20. The two sensing elements 20 are arranged at intervals along the first direction at opposite ends of the circuit board 10. By providing one sensing element 20 at each end of the circuit board 10, the lowest liquid level and the highest liquid level of the liquid to be detected can be detected. The above liquid level sensor 100 can be used in equipment that needs to control the lowest liquid level and the highest liquid level. For example, in a liquid heating device, if the liquid level is lower than the lowest liquid level, dry burning may occur, resulting in equipment damage; if the liquid level is higher than the highest liquid level, liquid overflow may occur, causing potential safety hazards. Therefore, it is necessary to use the above liquid level sensor 100 to monitor the lowest liquid level and the highest liquid level.

[0032] In one embodiment, as Figure 6 shown, the circuit board 10 is elongated in the first direction, and the number of sensing elements 20 is greater than two. Each sensing element 20 is arranged at intervals along the first direction of the circuit board 10. By arranging multiple sensing elements 20 at intervals in the first direction, the liquid level changes at multiple positions can be monitored. The above liquid level sensor 100 is applicable to equipment with multiple preset liquid level heights. Optionally, the multiple sensing elements 20 are arranged at equal intervals in the first direction.

[0033] Please refer to Figure 7 , in one embodiment, the circuit board 10 is elongated in the first direction, and there is one sensing element 20. The opposite ends of the sensing element 20 in the first direction respectively extend to the opposite ends of the circuit board 10. The length of the sensing element 20 in the first direction is set to be approximately equal to the length of the circuit board 10, so that the capacitance change in the sensing element 20 has a one-to-one correspondence with the liquid level change of the liquid to be detected. Therefore, the liquid level change of the liquid to be detected can be continuously monitored, and thus the liquid level height of the liquid to be detected can be accurately reflected.

[0034] In one embodiment, as Figure 8 shown, the circuit board 10 is a multilayer board. The circuit board 10 includes a top layer 11, a signal layer 12, and a bottom layer 13 that are stacked. Each layer is provided with an insulating medium 14. The insulating medium 14 can be epoxy glass cloth or phenolic resin glass cloth, etc. The top layer 11 is provided with a first shielding member 111, the bottom layer 13 is provided with a second shielding member 131 that is spaced apart and opposed to the first shielding member 111, and the signal layer 12 is provided with a signal line 121. The signal line 121 is electrically connected to the sensing element 20, and the signal line 121 can transmit the signal detected by the sensing element 20. The signal line 121 is arranged between the first shielding member 111 and the second shielding member 131. The first shielding member 111 and the second shielding member 131 can be made of metal. The first shielding member 111 and the second shielding member 131 are spaced apart and opposed to form a capacitor. The signal line 121 is arranged between the first shielding member 111 and the second shielding member 131, which can prevent the signal line 121 from generating an induced capacitance, thereby reducing the influence of the signal line 121 on the liquid level detection accuracy.

[0035] The first shielding member 111 and the second shielding member 131 may be a covering layer or a shielding cover formed on the insulating medium 14, such as silver paste, a shielding film, etc. In one embodiment, the top layer 11 and the bottom layer 13 are provided with copper cladding. The copper cladding forms the first shielding member 111 on the top layer 11, and the copper cladding forms the second shielding member 131 on the bottom layer 13. Setting the copper cladding to form the shielding member can simplify the processing technology of the circuit board 10 and reduce the cost.

[0036] In one embodiment, as Figure 8 shown, the liquid level sensor 100 further includes a processor 30. The processor 30 is connected to the sensing member 20 through a signal line 121. The processor 30 is configured to process the signals detected by the sensing member 20. The first shielding member 111 and the second shielding member 131 can be connected to the ground port of the processor 30. The processor 30 may be integrated on the circuit board 10, that is, the processor 30 and the circuit board 10 are integrally provided; the processor 30 may also be separately provided from the circuit board 10, that is, the processor 30 is provided outside the circuit board 10, and no specific limitation is made here.

[0037] This application provides a liquid level detection device. Please refer to Figure 9 , the liquid level detection device 500 includes the liquid level sensor 100 as described above and a housing 510. The liquid level sensor 100 is accommodated in the housing 510. The cross-sectional shape of the inner space formed by enclosing the housing 510 is adapted to the shape of the sensing member. The distance between the outer wall of the sensing member 20 and the inner wall of the housing 510 is less than a preset value, so that the sensing member 20 is as close as possible to the housing 510 to increase the sensing area of the sensing member 20, thereby improving the sensitivity of the liquid level sensor 100. The gap between the inner wall of the housing 510 and the liquid level sensor 100 is filled with a filling medium 520. The housing 510 may be made of plastic or other non-metallic materials. Encapsulating the liquid level sensor 100 in the housing 510, the housing 510 can provide protection for the liquid level sensor 100, so that the liquid level sensor 100 is protected from the erosion of the liquid to be detected, and the service life of the liquid level sensor 100 can be extended.

[0038] Optionally, the filling medium 520 is glue, which fills the gap between the inner wall of the housing 510 and the liquid level sensor 100 after hardening; or other materials with fluidity or plasticity are filled in the gap between the inner wall of the housing 510 and the liquid level sensor 100, and the filling medium 520 is formed after the fluidity or plasticity material hardens. By pouring the filling medium 520 into the gap between the inner wall of the housing 510 and the liquid level sensor 100, on the one hand, the filling medium 520 can fix the liquid level sensor 100, prevent the liquid level sensor 100 from shifting, and improve the reliability of the liquid level detection device 500; on the other hand, the filling medium 520 also has a protective effect, preventing the liquid level sensor 100 from being eroded and improving the service life of the liquid level detection device 500; in addition, the dielectric constant of the filling medium 520 is greater than that of air. For example, the relative dielectric constant of glue is usually 2.5 - 4.0. Wrapping the filling medium 520 around the outer periphery of the circuit board 10 can improve the sensitivity of the liquid level sensor 100, thereby improving the detection accuracy of the liquid level detection device 500.

[0039] This application provides an electronic device. Please refer to Figure 10 , the electronic device 700 includes the liquid level detection device 500 as described above. The electronic device 700 is provided with a liquid storage cavity 710, and the liquid level detection device 500 is installed in the liquid storage cavity 710. The liquid storage cavity 710 can hold liquids such as coolant, water, etc. The liquid level detection device 500 can detect the change of the liquid level of the liquid contained in the liquid storage cavity 710, so as to ensure the normal operation of the device. The electronic device 700 may also include other components such as a control main board. The above electronic device is only one embodiment of this application, and other electronic devices with the liquid level detection device 500 are also within the protection scope of this application. The specific internal structure of the electronic device will not be elaborated here.

[0040] The above are only some embodiments of this application, and thus do not limit the protection scope of this application. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of this application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of this application.

Claims

1. A liquid level sensor, characterized in that, It includes a circuit board and an induction element, wherein the induction element is electrically connected to the circuit board and is used as a plate of a capacitor; The liquid level sensor has a first direction, and the sensing element is at least partially arranged around the periphery of the circuit board along a direction perpendicular to the first direction. There is a gap between the sensing element and the circuit board. In a reference section perpendicular to the first direction, the sensing element is at least partially curved, and the size of the sensing element along the circumferential direction is larger than the size of the circuit board.

2. The liquid level sensor according to claim 1, wherein The induction component is in the shape of a hollow cylinder and is sleeved outside the circuit board.

3. The liquid level sensor according to claim 2, characterized in that, The induction member is provided with an opening, and the opening cuts off the side wall of the induction member.

4. The liquid level sensor according to claim 3, wherein A limiting groove is provided on the side of the circuit board, and the sensing element is engaged in the limiting groove.

5. The liquid level sensor according to claim 2, wherein, The shape of the sensing element in a reference cross section perpendicular to the first direction is circular, elliptical or polygonal.

6. The liquid level sensor according to any one of claims 1-5, characterized in that, The induction component is connected to the circuit board by welding.

7. The liquid level sensor according to any one of claims 1-5, characterized in that The circuit board is in an elongated strip shape in the first direction; There are two inductive elements, and the two inductive elements are spaced apart and arranged at opposite ends of the circuit board along the first direction; or, The number of the induction elements is greater than two, and the induction elements are arranged at intervals along the first direction of the circuit board; or, There is one inductive element, and opposite ends of the inductive element in the first direction extend to opposite ends of the circuit board respectively.

8. The liquid level sensor according to any one of claims 1-5, characterized in that, The circuit board includes a top layer, a signal layer and a bottom layer which are stacked together. The top layer is provided with a first shielding component, the bottom layer is provided with a second shielding component which is spaced apart from the first shielding component, the signal layer is provided with a signal line which is electrically connected to the induction component and is arranged between the first shielding component and the second shielding component.

9. A liquid level detection device, characterized in that, It comprises a liquid level sensor as described in any one of claims 1 to 8 and a shell, the liquid level sensor is accommodated in the shell, the distance between the outer wall of the sensing element and the inner wall of the shell is smaller than a preset value, and the gap between the inner wall of the shell and the liquid level sensor is filled with a filling medium.

10. An electronic device, characterized in that, The liquid level detection device according to claim 9 is included, wherein the electronic device is provided with a liquid storage cavity, and the liquid level detection device is installed in the liquid storage cavity.

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