Flexible ultrasonic liquid level sensor and flexible ultrasonic liquid level sensing assembly

Abstract

The utility model relates to a flexible ultrasonic liquid level sensor and a flexible ultrasonic liquid level sensing assembly, the flexible ultrasonic liquid level sensor comprises a support layer, a cavity is formed in the support layer, the support layer comprises a bottom wall and a side wall surrounding the bottom wall, and the cavity is used for accommodating liquid entering from the outside; the first flexible ultrasonic sensor is used for measuring the sound velocity of the liquid, and the first flexible ultrasonic sensor is attached to the outer side surface of the side wall; the second flexible ultrasonic sensor is used for measuring the liquid level height of the liquid based on the sound velocity, and the second flexible ultrasonic sensor is attached to the outer side surface of the bottom wall; and the packaging layer covers the outer side surface of the supporting layer, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor. Therefore, parameters do not need to be configured in advance, operation is simple, and the accuracy of the liquid level testing result is greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor technical field, especially relate to a flexible ultrasonic liquid level sensor and flexible ultrasonic liquid level sensing assembly. BACKGROUND

[0002] Liquid level measurement is an important parameter in many industrial processes, widely used in semiconductor, pharmaceutical, food and other industries. At present, the floating ball type liquid level meter or ultrasonic liquid level meter is commonly used, among them, the ultrasonic liquid level meter can realize continuous detection of liquid level. Ultrasonic liquid level meter realizes continuous liquid level monitoring through the propagation time and reflection characteristics of sound waves. Generally, the ultrasonic liquid level meter includes an ultrasonic sensor, which emits high-frequency sound waves to the liquid through the ultrasonic transmitter so that the ultrasonic signal propagates in the medium (such as gas or liquid), and when it encounters the liquid-gas surface, it will reflect back, and the ultrasonic sensor will receive the ultrasonic signal reflected from the liquid surface. The propagation speed of ultrasonic wave depends on the characteristics of the medium, and the change of liquid level will affect the propagation distance of ultrasonic wave, therefore, the ultrasonic liquid level meter calculates the height of liquid level by measuring the propagation time of ultrasonic wave (from emission to reception of reflected wave).

[0003] At present, the existing ultrasonic liquid level meter scheme can be divided into top type and bottom type, and the core part of both is piezoelectric ceramic ultrasonic sensor. The difference is that the ultrasonic of top type ultrasonic liquid level meter needs to pass through gas medium, and the ultrasonic of bottom type ultrasonic liquid level meter needs to pass through liquid medium. Both sensors have the problem of inaccurate test results caused by the change of medium and its state. In order to improve this problem, the prior art adopts the scheme of pre-configuring sound velocity parameters, however, this scheme is inconvenient to operate and has limited improvement on the accuracy of test structure. SUMMARY

[0004] The technical problem solved by the utility model is to provide a flexible ultrasonic liquid level sensor and flexible ultrasonic liquid level sensing assembly to improve the accuracy of test results.

[0005] In order to solve the above technical problems, the technical scheme of the utility model provides a flexible ultrasonic liquid level sensor, which comprises: a support layer, a cavity is formed in the support layer, the support layer comprises a bottom wall and a side wall surrounding the bottom wall, and the cavity is used to accommodate liquid entering from outside; a first flexible ultrasonic sensor for measuring the sound velocity of the liquid, the first flexible ultrasonic sensor is in close contact with the outer surface of the side wall; a second flexible ultrasonic sensor for measuring the liquid level height of the liquid based on the sound velocity, the second flexible ultrasonic sensor is in close contact with the outer surface of the bottom wall; and a packaging layer covering the outer surface of the support layer, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor.

[0006] Optionally, the flexible ultrasonic liquid level sensor further comprises a liquid inlet hole penetrating through the support layer and the packaging layer, the cavity is connected to the outside of the flexible ultrasonic liquid level sensor through the liquid inlet hole, and the liquid enters the cavity through the liquid inlet hole.

[0007] Optionally, the first flexible ultrasonic sensor is arranged opposite to the liquid inlet hole.

[0008] Optionally, the flexible ultrasonic liquid level sensor further comprises an exhaust hole penetrating through the support layer and the packaging layer, and the distance between the exhaust hole and the bottom wall is greater than the distance between the liquid inlet hole and the bottom wall.

[0009] Optionally, the packaging layer is arranged outside the support layer, and a closed interlayer gap is formed between the packaging layer and the support layer, and the first flexible ultrasonic sensor and the second flexible ultrasonic sensor are located in the interlayer gap.

[0010] Optionally, the flexible ultrasonic liquid level sensor further comprises a first transmission line connected to the first flexible ultrasonic sensor and a second transmission line connected to the second flexible ultrasonic sensor, and the first transmission line and the second transmission line are accommodated in the interlayer gap.

[0011] Optionally, the support layer and the packaging layer are made of a rigid material.

[0012] Optionally, in the height direction of the flexible ultrasonic liquid level sensor, the distance between the bottom end of the first flexible ultrasonic sensor and the bottom wall is greater than or equal to 1 mm.

[0013] Optionally, the support layer is a hollow cylindrical shape.

[0014] Optionally, the shape of the second flexible ultrasonic sensor is adapted to the shape of the bottom wall.

[0015] Optionally, the first flexible ultrasonic sensor comprises a first flexible substrate, a first lower electrode, a first piezoelectric film and a first upper electrode stacked in sequence, the first flexible substrate is made of a flexible polyimide substrate, and the first piezoelectric film is made of a polyvinylidene fluoride copolymer film; and the second flexible ultrasonic sensor comprises a second flexible substrate, a second lower electrode, a second piezoelectric film and a first upper electrode stacked in sequence, the second flexible substrate is made of a flexible polyimide substrate, and the second piezoelectric film is made of a polyvinylidene fluoride copolymer film.

[0016] Optionally, the first lower electrode and the second lower electrode are disconnected from each other, the first upper electrode and the second upper electrode are connected, one side of the first lower electrode is connected to a first lower electrode lead wire, one side of the second lower electrode is connected to a second lower electrode lead wire, and at least one of the first upper electrode and the second upper electrode is connected to an upper electrode lead wire.

[0017] Optionally, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor are disconnected with each other.

[0018] Correspondingly, the technical scheme of the utility model also provides a flexible ultrasonic liquid level sensing assembly, comprising: the flexible ultrasonic liquid level sensor of any one of the above; a driving control unit for driving and controlling the first flexible ultrasonic sensor and the second flexible ultrasonic sensor.

[0019] Compared with the prior art, the technical scheme of the utility model embodiment has the following beneficial effects:

[0020] The flexible ultrasonic liquid level sensor and the flexible ultrasonic liquid level sensing assembly provided by the technical scheme of the utility model, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor are flexible, and the first flexible ultrasonic sensor is attached to the outer surface of the side wall of the supporting layer, and the second flexible ultrasonic sensor is attached to the outer surface of the bottom wall of the supporting layer, therefore, on the one hand, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor can be adapted and attached to various shapes of surfaces, on the other hand, the liquid in the cavity can be monitored in real time to obtain the speed of the medium, and the liquid level height is continuously determined based on this, therefore, it is not necessary to configure parameters in advance and the operation is simple, and the accuracy of the liquid level test result is greatly improved.

[0021] Further, since the first piezoelectric film adopts polyvinylidene fluoride copolymer, and the second piezoelectric film adopts polyvinylidene fluoride copolymer, compared with piezoelectric ceramics, it has the advantages of small tailing, clear echo signal and large longitudinal resolution. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic view of the flexible ultrasonic liquid level sensor of an embodiment of the utility model;

[0023] Figure 2 is a top view structural schematic view of the first flexible ultrasonic sensor and the second flexible ultrasonic sensor of an embodiment of the utility model;

[0024] Figure 3 is a sectional view structural schematic view of the first flexible ultrasonic sensor of an embodiment of the utility model;

[0025] Figure 4 is a sectional view structural schematic view of the second flexible ultrasonic sensor of an embodiment of the utility model;

[0026] Figure 5 is a sectional view structural schematic view of the first flexible ultrasonic sensor and the second flexible ultrasonic sensor of another embodiment of the utility model.

[0027] Reference numerals:

[0028] 100 - support layer; 101 - cavity; bottom wall 110; side wall 120;

[0029] 200 - encapsulation layer; 210 - interlayer gap;

[0030] 310 - liquid inlet hole; 320 - air outlet hole;

[0031] 400 - first flexible ultrasonic sensing part; 410, 411 - first flexible substrate; 420, 421 - first lower electrode; 430, 431 - first piezoelectric film; 440, 441 - first upper electrode; 450, 451 - first backing layer;

[0032] 500 - second flexible ultrasonic sensing part; 510, 411 - second flexible substrate; 520, 521 - second lower electrode; 530, 531 - second piezoelectric film; 540, 541 - second upper electrode; 550, 551 - first backing layer. DETAILED DESCRIPTION

[0033] As described in the background, the existing ultrasonic liquid level meter scheme is inconvenient to operate and has limited improvement in the accuracy of test results.

[0034] To solve the above technical problems, the technical scheme of the utility model provides a flexible ultrasonic liquid level sensor and a flexible ultrasonic liquid level sensing assembly, by setting a flexible first flexible ultrasonic sensor on the outer side surface of the side wall of the support layer, and setting a flexible second flexible ultrasonic sensor on the bottom side surface of the support layer, simple operation is realized and accurate liquid level test results can be obtained.

[0035] In order to make the above-mentioned purposes, characteristics and beneficial effects of the utility model more obvious and easy to understand, the technical solutions in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

[0036] The terms "first", "second", "third", "fourth" etc. (if present) in the description and claims of the present application and the drawings, if any, are used for distinguishing between like elements and are not necessarily used to describe a particular sequential or chronological order. It is to be understood that the use of such terms is sup- plementary to, and does not limit, the scope of the application, which is defined by the appended claims and their equivalents. Furthermore, the terms "comprising", "having", "including", and "containing" and any variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, system, product, or apparatus that comprises, has, includes or contains an item or list of items who does not also preclude any other- item or list of items not expressly mentioned or failing under the same. Additionally, directional terms such as above, below, upper, lower, up, down, left, right, top, bottom, etc. are used with respect to the exemplary embodiments as they are shown in the drawings, with up or upper direction being toward the top of the corresponding drawing and down or lower direction being toward the bottom of the corresponding drawing.

[0037] Figure 1 is a structural schematic view of a flexible ultrasonic liquid level sensor according to an embodiment of the present application, Figure 2 is a top view structural schematic view of a first flexible ultrasonic sensor and a second flexible ultrasonic sensor according to an embodiment of the present application, Figure 3 is a sectional view structural schematic view of the first flexible ultrasonic sensor according to an embodiment of the present application, Figure 4 is a sectional view structural schematic view of the second flexible ultrasonic sensor according to an embodiment of the present application.

[0038] Reference is made to Figures 1 to 4 , the flexible ultrasonic liquid level sensor comprises a support layer 100, an encapsulation layer 200, a first flexible ultrasonic sensor 400 and a second flexible ultrasonic sensor 500.

[0039] The support layer 100 has a cavity 101 formed therein, which is used to accommodate liquid entering from outside. The support layer 100 comprises a bottom wall 110 and a side wall 120 surrounding the bottom wall 110.

[0040] Preferably, the support layer 100 is made of a rigid material, so as to support the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500. Specifically, the material of the support layer 100 includes but is not limited to metal, glass and plastic.

[0041] In one embodiment, the support layer 100 is hollow and cylindrical, so as to reduce the difficulty of preparation.

[0042] The first flexible ultrasonic sensor 400 is used to determine the speed of sound of the liquid.

[0043] The first flexible ultrasonic sensor 400 is attached to the outer surface of the side wall 120.

[0044] The first flexible ultrasonic sensor 400 emits high-frequency sound waves to the liquid in the cavity 101, and the ultrasonic signals propagate in the liquid. When the ultrasonic signals encounter the inner surface of the liquid-supporting layer 100, they are reflected back. The first flexible ultrasonic sensor 400 receives the reflected ultrasonic signals to determine the speed of sound of the liquid.

[0045] In some embodiments, the distance between the bottom end of the first flexible ultrasonic sensor 400 and the bottom wall 110 in the height direction of the flexible ultrasonic liquid level sensor is greater than or equal to 1 millimeter.

[0046] Preferably, the bottom end of the first flexible ultrasonic sensor 400 is flush with the bottom wall.

[0047] In one embodiment, the first flexible ultrasonic sensor 400 is attached to the outer surface of the side wall 120.

[0048] Specifically, the first flexible ultrasonic sensor 400 includes a first flexible substrate 410, a first lower electrode 420, a first piezoelectric film 430, and a first upper electrode 440 stacked in sequence.

[0049] The first flexible substrate 410 is made of a flexible polyimide substrate, and the first piezoelectric film 430 is made of a polyvinylidene fluoride copolymer film.

[0050] On the one hand, the first flexible substrate 410 forms a flexible first flexible ultrasonic sensor 400, which is suitable for attaching to side walls 120 of various shapes. On the other hand, the first piezoelectric film 430 is made of a polyvinylidene fluoride copolymer film. Therefore, compared with ultrasonic sensors using piezoelectric ceramics, the first flexible ultrasonic sensor 400 has the advantages of small tail, clear echo signal, and large longitudinal resolution.

[0051] In one embodiment, the first lower electrode 420 is a nano-silver lower electrode structure. The first flexible ultrasonic sensor 400 further includes a first lower electrode lead (not shown) connected to one side of the first lower electrode 420, and a lead connected to one side of the first upper electrode 440.

[0052] Further, the nano-silver lower electrode structure and the lead connected thereto have a thickness of 5 microns.

[0053] In some embodiments, the first flexible ultrasonic sensor 400 further includes at least one of a first backing layer 450, a first matching layer, a first protective layer, and a first adhesive layer.

[0054] The second flexible ultrasonic sensor 500 is used to measure the liquid level of the liquid based on the speed of sound, and the second flexible ultrasonic sensor 500 is attached to the outer surface of the bottom wall 110.

[0055] Specifically, the second flexible ultrasonic sensor 500 emits high-frequency sound waves to the liquid in the cavity 101, and the ultrasonic signals propagate in the liquid. When the ultrasonic signals encounter the liquid-gas surface in the cavity 101, they are reflected back. The second flexible ultrasonic sensor 500 receives the reflected ultrasonic signals, and thus measures the liquid level continuously in combination with the speed of sound.

[0056] In one embodiment, the second flexible ultrasonic sensor 500 is attached to the outer surface of the bottom wall 110.

[0057] Specifically, the second flexible ultrasonic sensor 500 includes a second flexible substrate 510, a second lower electrode 520, a second piezoelectric film 530, and a second upper electrode 540 stacked in sequence.

[0058] The second flexible substrate 510 is made of a flexible polyimide substrate, and the second piezoelectric film 530 is made of a polyvinylidene fluoride copolymer film.

[0059] On the one hand, the second flexible ultrasonic sensor 500 is flexible based on the second flexible substrate 510, so as to be attached to bottom walls 110 of various shapes. On the other hand, the second piezoelectric film 530 is made of a polyvinylidene fluoride copolymer film (PVDF copolymer film), so that the second flexible ultrasonic sensor 500 has the advantages of small tail, clear echo signal, and large longitudinal resolution compared with ultrasonic sensors using piezoelectric ceramics.

[0060] In one embodiment, the second lower electrode 520 is a nano-silver lower electrode structure. The second flexible ultrasonic sensor 500 further includes a second lower electrode lead (not shown) connected to one side of the second lower electrode 520, and a lead connected to one side of the second upper electrode 540.

[0061] In some embodiments, the second flexible ultrasonic sensor 500 further includes at least one of a second backing layer 550, a second matching layer, a second protective layer, and a second adhesive layer.

[0062] Preferably, the shape of the second flexible ultrasonic sensor 500 is adapted to the shape of the bottom wall 110. For example, it can be circular or the like.

[0063] In the present embodiment, the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 are disconnected from each other, that is, they are independent of each other in structure. Thus, they have better assembly freedom. Correspondingly, the lead connected to the first upper electrode 440 and the lead connected to the second upper electrode 540 are independent of each other.

[0064] In another embodiment, referring to Figure 5 , the first lower electrode 421 and the second lower electrode 521 are disconnected from each other, and the first upper electrode 441 and the second upper electrode 541 are connected. On this basis, one side of the first lower electrode 421 is connected to the first lower electrode lead, one side of the second lower electrode 521 is connected to the second lower electrode lead, and at least one of the first upper electrode 441 and the second upper electrode 541 is connected to the upper electrode lead.

[0065] It should be noted that, in order to facilitate understanding, Figure 5 , the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 are distinguished by the two sides of the dashed line.

[0066] Since the first lower electrode 421 and the second lower electrode 521 are disconnected from each other, and are respectively connected to the first lower electrode lead and the second lower electrode lead, the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 can still be used to detect different objects, respectively. At the same time, by connecting the first upper electrode 441 and the second upper electrode 541, one lead (i.e. the upper electrode lead) can be used to connect both of them, reducing the number of leads.

[0067] Further, the first flexible substrate 411 and the second flexible substrate 511 are connected. That is to say, they together constitute an integral flexible substrate, wherein the first flexible substrate 411 is part of the integral flexible substrate located at the side wall 120, and the second flexible substrate 511 is part of the integral flexible substrate located at the bottom wall 110. On this basis, the surface of the integral flexible substrate forms the disconnected (independent of each other) first lower electrode 421 and the second lower electrode 521.

[0068] Further, the first piezoelectric film 431 and the second piezoelectric film 531 are connected. That is to say, they can constitute an integral piezoelectric film structure, which is formed on the surface of the first lower electrode 421, the surface of the second lower electrode 521 and the exposed surface of the integral flexible substrate.

[0069] Further, the first upper electrode 441 and the second upper electrode 541 together constitute an integral structure, which is located on the surface of the integral piezoelectric film structure.

[0070] Further, the first backing layer 451 and the second backing layer 551 together constitute an integral structure.

[0071] The encapsulation layer covers the outer surface of the support layer 100, the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500.

[0072] Since the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 are both flexible, and the outer side surface of the side wall 120 of the support layer 100 is attached to the first flexible ultrasonic sensor 400, and the outer side surface of the bottom wall 110 of the support layer 100 is attached to the second flexible ultrasonic sensor 500, on the one hand, the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 can be adapted to and attached to surfaces of various shapes, and on the other hand, the liquid in the cavity 101 can be monitored in real time to obtain the speed of the medium, and the liquid level height can be continuously determined based on this, so that the liquid level test result is greatly improved in accuracy without the need for prior parameter configuration and simple operation.

[0073] Preferably, the packaging layer 200 is made of a rigid material to better protect the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500. Specifically, the material of the packaging layer 200 includes but is not limited to metal, glass and plastic.

[0074] In the embodiment, the packaging layer 200 is sleeved on the outside of the support layer 100, and a closed interlayer gap 210 is formed between the packaging layer 200 and the support layer 100, and the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 are located in the interlayer gap 210. Thus, the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 are further protected.

[0075] In the embodiment, the flexible ultrasonic liquid level sensor further comprises a first transmission line (not shown) connected to the first flexible ultrasonic sensor 400 and a second transmission line (not shown) connected to the second flexible ultrasonic sensor 500, and the first transmission line and the second transmission line are accommodated in the interlayer gap 210. Thus, the interlayer gap 210 can also be used for wiring of the first transmission line and the second transmission line.

[0076] In some embodiments, the flexible ultrasonic liquid level sensor further comprises a liquid inlet hole 310 penetrating the support layer 100 and the packaging layer 200, and the cavity 101 is connected to the outside of the flexible ultrasonic liquid level sensor through the liquid inlet hole 310 to allow the liquid to enter the cavity 101.

[0077] Specifically, the liquid inlet hole 310 has a side wall penetrating and closing the interlayer gap 210, and the side wall forms a liquid inlet channel.

[0078] Preferably, the first flexible ultrasonic sensor 400 is arranged opposite to the liquid inlet hole 310.

[0079] In some embodiments, the flexible ultrasonic liquid level sensor further comprises an exhaust hole 320 penetrating the support layer 100 and the packaging layer 200, and the distance between the exhaust hole 320 and the bottom wall 110 is greater than the distance between the liquid inlet hole 310 and the bottom wall 110.

[0080] Specifically, the exhaust hole 320 can be located above the liquid inlet hole 310.

[0081] The working principle of the flexible ultrasonic liquid level sensor is described below by taking 316L stainless steel with an outer diameter of 9.53 mm, a bottom wall 110 with a thickness of 0.5 mm, and a side wall 120 with a thickness of 0.89 mm as a support material.

[0082] It should be noted that, in order to facilitate understanding, Figure 1 The blue dashed line represents the ultrasonic signal (emitted and reflected back) corresponding to the first flexible ultrasonic sensor 400, and the red dashed line represents the ultrasonic signal (emitted and reflected back) corresponding to the second flexible ultrasonic sensor 500.

[0083] L = V x t / 2. Wherein, L is the liquid level height (from the sensor to the liquid surface), V is the propagation speed of ultrasonic wave in air or liquid, and t is the total propagation time of ultrasonic wave. It should be understood that, since the signal is emitted from the sensor and then reflected back, it is necessary to divide by 2 to calculate the actual liquid level height.

[0084] In addition, the sound speed of 316L stainless steel is 5740 m / s.

[0085] When the one-way echo time (i.e. the total time of ultrasonic signal emission and reflection back) measured by the first flexible ultrasonic sensor 400 is 10.2 μs, the time required for double travel in the 0.89 mm 316L stainless steel pipe wall is (0.89 mm) ÷ (5740 m / s) x 2 = 0.31 μs, and thus the time required for double travel in the medium is (10.2 μs) - (0.31 μs) = 9.89 μs, and the sound speed of the liquid in this state is (7.75 mm) x 2 ÷ (9.89 μs) = 1567 m / s.

[0086] On this basis, the height of the liquid surface can be calculated by the one-way echo time measured by the second flexible ultrasonic sensor 500. For example, the one-way echo time is 100.3 μs, and thus the time required for double travel in the 0.5 mm 316L stainless steel pipe wall is (0.5 mm) ÷ (5740 m / s) x 2 = 0.17 μs, and thus the time required for double travel in the liquid is (100.3 μs) - (0.17 μs) = 100.13 μs, and thus the liquid level height is (1567 m / s) x (100.13 μs) ÷ 2 = 78.45 mm.

[0087] Correspondingly, the utility model embodiment further provides a flexible ultrasonic liquid level sensing assembly, comprising: the above-mentioned flexible ultrasonic liquid level sensor and a drive control unit (not shown).

[0088] The drive control unit is used for driving the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500.

[0089] Specifically, the drive control unit is connected with the first flexible ultrasonic sensor 400 and the second flexible ultrasonic sensor 500 through the first data line and the second data line.

[0090] In some embodiments, the drive control unit comprises a drive and signal processing circuit, a data processing and transmission module, and an auxiliary function module.

[0091] Specifically, the drive and signal processing circuit comprises a pulse generator, a power amplification circuit, a signal amplification circuit, a filter circuit and a threshold detection circuit.

[0092] The data processing and transmission module comprises an ADC, a digital logic control, a data storage module, a communication module and a data protocol.

[0093] The auxiliary function module comprises a temperature compensation circuit module, a display circuit module and an alarm device. The temperature compensation circuit module can adjust the parameters in the circuit to make it have the same performance at different temperatures based on the characteristic changes of electronic components at different temperatures, by monitoring temperature changes and adjusting the parameters in the circuit according to the pre-set compensation parameters. The display circuit module is used for displaying corresponding state, numerical value and other information. The alarm device is used for alarming in the form of beeping or other forms when reaching the set threshold.

[0094] Although the utility model discloses as above, the utility model is not limited to this. Any person skilled in the art, without departing from the spirit and scope of the utility model, can make various changes and modifications, therefore the protection scope of the utility model should be the range limited by the claims.

Claims

1. A flexible ultrasonic liquid level sensor, characterized by, Comprise: a support layer, a cavity is formed in the support layer, the support layer comprises a bottom wall and a side wall surrounding the bottom wall, the cavity is used for accommodating liquid entering from outside; a first flexible ultrasonic sensor for measuring the speed of sound of the liquid, the first flexible ultrasonic sensor is attached to the outer surface of the side wall; a second flexible ultrasonic sensor for measuring the liquid level of the liquid based on the speed of sound, the second flexible ultrasonic sensor is attached to the outer surface of the bottom wall; a packaging layer covering the outer surface of the support layer, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor.

2. The flexible ultrasonic liquid level sensor of claim 1, wherein, Also comprising: a liquid inlet hole penetrating through the support layer and the packaging layer, the cavity is in communication with the outside of the flexible ultrasonic liquid level sensor through the liquid inlet hole, so that the liquid enters the cavity.

3. The flexible ultrasonic liquid level sensor of claim 2, wherein, The first flexible ultrasonic sensor is arranged opposite to the liquid inlet hole.

4. The flexible ultrasonic liquid level sensor of claim 2, wherein, Also comprising: an exhaust hole penetrating through the support layer and the packaging layer, the distance between the exhaust hole and the bottom wall is greater than the distance between the liquid inlet hole and the bottom wall.

5. The flexible ultrasonic liquid level sensor of claim 1, wherein, The packaging layer is sleeved on the outside of the support layer, and a closed interlayer gap is formed between the packaging layer and the support layer, the first flexible ultrasonic sensor and the second flexible ultrasonic sensor are located in the interlayer gap.

6. The flexible ultrasonic liquid level sensor of claim 5, wherein, Also comprising: a first transmission line connected to the first flexible ultrasonic sensor and a second transmission line connected to the second flexible ultrasonic sensor, the first transmission line and the second transmission line are accommodated in the interlayer gap.

7. The flexible ultrasonic liquid level sensor of claim 5, wherein, The support layer and the packaging layer are made of rigid material.

8. The flexible ultrasonic liquid level sensor of claim 1, wherein, The distance between the bottom end of the first flexible ultrasonic sensor and the bottom wall in the height direction of the flexible ultrasonic liquid level sensor is greater than or equal to 1mm.

9. The flexible ultrasonic liquid level sensor of claim 1, wherein, The support layer is hollow cylindrical.

10. The flexible ultrasonic liquid level sensor of claim 3, wherein, The shape of the second flexible ultrasonic sensor is adapted to the formation of the bottom wall.

11. The flexible ultrasonic liquid level sensor of any one of claims 1 to 9, wherein, The first flexible ultrasonic sensor comprises: a first flexible substrate, a first lower electrode, a first piezoelectric film and a first upper electrode stacked in sequence, the first flexible substrate is made of flexible polyimide substrate, and the first piezoelectric film is made of polyvinylidene fluoride copolymer film; the second flexible ultrasonic sensor comprises: a second flexible substrate, a second lower electrode, a second piezoelectric film and a first upper electrode stacked in sequence, the second flexible substrate is made of flexible polyimide substrate, and the second piezoelectric film is made of polyvinylidene fluoride copolymer film.

12. The flexible ultrasonic liquid level sensor of claim 11, wherein, The first lower electrode and the second lower electrode are disconnected, the first upper electrode and the second upper electrode are connected, one side of the first lower electrode is connected to a first lower electrode lead, one side of the second lower electrode is connected to a second lower electrode lead, and at least one of the first upper electrode and the second upper electrode is connected to an upper electrode lead.

13. The flexible ultrasonic liquid level sensor of claim 11, wherein, The first flexible ultrasonic sensor and the second flexible ultrasonic sensor are disconnected.

14. A flexible ultrasonic liquid level sensing assembly, characterized by, Comprise: the flexible ultrasonic liquid level sensor of any one of claims 1 to 13; a drive control unit for driving and controlling the first flexible ultrasonic sensor and the second flexible ultrasonic sensor.

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