CN220472849U

CN220472849U - Ceramic capacitor pressure sensor

Info

Publication number: CN220472849U
Application number: CN202322124297.XU
Authority: CN
Inventors: 冒周斌
Original assignee: Zhonghui Ruide Sensing Technology Suzhou Co ltd
Current assignee: Zhonghui Ruide Sensing Technology Suzhou Co ltd
Priority date: 2023-08-08
Filing date: 2023-08-08
Publication date: 2024-02-09
Anticipated expiration: 2033-08-08

Abstract

The utility model provides a ceramic capacitive pressure sensor, comprising: a substrate, on which a substrate electrode and a substrate electrode pad connected thereto are disposed; the membrane is provided with a membrane electrode and a membrane electrode pad connected with the membrane electrode, and the substrate is penetrated with a substrate electrode lead hole and a membrane electrode lead hole; the sealing layer is arranged between the substrate and the diaphragm, a closed cavity is formed among the substrate, the diaphragm and the sealing layer, the sealing layer comprises a first circular ring and a second circular ring arranged on the periphery of the first circular ring, and the substrate electrode and the diaphragm electrode are positioned in the first circular ring; wherein: the cross section shapes and the sizes of the base plate and the diaphragm are the same, and the cross section shapes of the base plate and the diaphragm are square or octagonal.

Description

Ceramic capacitor pressure sensor

Technical Field

The utility model relates to the technical field of sensors, in particular to a ceramic capacitor pressure sensor.

Background

The square ceramic capacitance sensor can print the capacitance and glass paste in one step, and realize the assembly of each monomer through cutting later, so that the cost and manufacturability are better, but the square ceramic capacitance sensor has certain defects, and the lead of the square ceramic capacitance sensor in the prior art is mainly led out by a side card and a rectangular design. The side card has certain technological difficulty, cost and technological stability at present in China. The rectangle design makes the pressure sensing area not be in middle, needs to have offset switching groove to guarantee its location, and to the occasion that has anti-icing, anti-soot, relies on the design of paranoid to hardly satisfy the demand.

In addition, the rectangular ceramic capacitive sensor in the prior art has the problem that the parasitic capacitance interference is relatively large due to the limited size of the pressure sensing area, so that the testing precision is affected.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art, and provides a ceramic capacitor pressure sensor which is used for improving the technical problems caused by limited application due to bias of a pressure sensing area and great difficulty in developing side clamps and the problem of small rectangular ceramic capacitor pressure sensing area.

To achieve the above and other objects, the present utility model is achieved by comprising the following technical solutions: the utility model provides a ceramic capacitive pressure sensor, comprising: a substrate, on which a substrate electrode and a substrate electrode pad connected thereto are disposed; the membrane is provided with a membrane electrode and a membrane electrode pad connected with the membrane electrode, a substrate electrode lead hole and a membrane electrode lead hole penetrate through the substrate, the substrate electrode pad is positioned on the substrate electrode lead hole, and the membrane electrode pad is positioned on the membrane electrode lead hole; the sealing layer is arranged between the substrate and the diaphragm, a closed cavity is formed among the substrate, the diaphragm and the sealing layer, the sealing layer comprises a first circular ring and a second circular ring arranged on the periphery of the first circular ring, the closed cavity is positioned in the first circular ring, and the substrate electrode and the diaphragm electrode are positioned in the first circular ring; wherein: the cross section shape and the size of the substrate are the same as those of the diaphragm, the cross section shape of the substrate and the diaphragm is square or octagonal, the substrate electrode pad and the diaphragm electrode pad are arranged outside the first circular ring, and funnel structures are arranged at the two ends of the cross section of the substrate electrode lead hole and the two ends of the cross section of the diaphragm electrode lead hole.

Compared with the prior art, the ceramic capacitor pressure sensor has the following beneficial effects: the scheme combines the processing advantages of square ceramics, and simultaneously utilizes the scheme of lead insertion, so that the ceramic sensitive unit can be made into a square (or octagon) so as to facilitate product packaging, and meanwhile, the side card assembly process of the square sensor with great difficulty is avoided.

Drawings

FIG. 1 is a diagram showing a structure of a sensor according to an embodiment of the present utility model.

Fig. 2 is a diagram showing a structure of a substrate according to an embodiment of the utility model.

FIG. 3 is a diagram showing a structure of a diaphragm according to an embodiment of the present utility model.

Fig. 4 shows an exploded view of a sensor in an embodiment of the utility model.

Fig. 5 shows a structure of a through hole of a substrate according to the present utility model.

Fig. 6 shows a cross-sectional view of the sensor of the present utility model.

Fig. 7 shows a schematic cross-sectional view of the through hole of fig. 6 according to the present utility model.

Detailed Description

Please refer to fig. 1 to 7. Other advantages and effects of the present utility model will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present utility model with reference to specific examples. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model.

As shown in fig. 1, the present utility model provides a ceramic capacitive pressure sensor, the operating principle of which can be exemplified as follows. The internal electrode of the ceramic capacitor pressure sensor is not contacted with the external environment, and the pressure directly acts on the outer surface of the diaphragm 2. The diaphragm 2 and the inner surface of the substrate 1 are sputtered or screen-printed with electrodes to form a double-capacitance structure, and the capacitance change value caused by the deformation of the capacitance cavity is proportional to the deformation amount of the diaphragm according to the principle of a parallel plate capacitor, namely the diaphragm 2 is proportional to the applied pressure, so that the pressure of the corresponding medium is measured. When the diaphragm 2 and the substrate 1 are in a non-contact state in operation, namely when the diaphragm 2 is deformed by an applied load, the distance between the capacitor cavities is reduced, and the upper electrode and the lower electrode are gradually close, but are not in contact all the time.

As shown in fig. 1, the pressure sensor includes a substrate 1, where the substrate 1 may be made of alumina or zirconia, and the cross-sectional structure of the substrate 1 may be square or polygonal, and further may be a regular polygon, and the regular polygon may be a regular octagon. The utility model adopts square or polygonal structure to replace circular structure, and can realize that the ceramic capacitance pressure sensor is cut into a plurality of products after single printing, thereby effectively improving the production efficiency and reducing the production cost. The substrate 1 may be a thick plate in the pressure sensor, the thickness of the substrate 1 may be 1 to 10mm, and the side length of the substrate 1 may be more than 5mm.

As shown in fig. 2, the substrate 1 is provided with a substrate electrode 41, the thickness of the substrate electrode 41 may be less than 10 μm, for example, 5 μm, 2 μm, etc., the material of the substrate electrode 41 may be conductive paste, for example, gold, and the substrate 1 is further provided with an annular substrate electrode 42, the substrate electrode 41 may be disposed at a middle position of the substrate 1, the annular substrate electrode 42 is located at the periphery of the substrate electrode 41, the substrate electrode 41 may be a circular electrode, and the annular substrate electrode 42 may be an unsealed circular electrode. The distance between the annular substrate electrode 42 and the substrate electrode 41 may be less than 2mm, for example 1 to 1.5mm. The substrate electrode 41 is connected to a substrate electrode pad 41a, and the annular substrate electrode 42 is connected to an annular substrate electrode pad 42a.

As shown in fig. 3, the pressure sensor further includes a diaphragm 2, where the diaphragm 2 may be an elastic ceramic diaphragm, the diaphragm 2 may be made of alumina or zirconia, the cross-sectional structure of the diaphragm 2 may be square or polygonal, and further may be a regular polygon, and the regular polygon may be a regular octagon. Further, the cross-sectional shapes and sizes of the membrane 2 and the substrate 1 are the same. Specifically, the thickness of the membrane 2 may be 0.05 to 1mm.

As shown in fig. 3, a membrane electrode 51 is disposed on one surface of the membrane 2, the thickness of the membrane electrode 51 may be the same as that of the substrate electrode 41, an annular membrane electrode 52 is further disposed on the membrane 2, the annular membrane electrode 52 may be an unsealed ring, the membrane electrode 51 may be disposed in a middle position of the membrane 2, the annular membrane electrode 52 is located at the periphery of the membrane electrode 51, the membrane electrode 51 may be a circular electrode, and the annular membrane electrode 52 may be an annular electrode. The distance between the annular diaphragm electrode 52 and the diaphragm electrode 51 may be less than 2mm, for example 1 to 1.5mm. The area of the electrode (41, 42) covered on the substrate and the area of the electrode (51, 52) covered on the membrane can be the same, namely the upper part and the lower part can be overlapped. The diaphragm electrode 51 is connected to a diaphragm electrode pad 51a, and the annular diaphragm electrode 52 is connected to an annular diaphragm electrode pad 52a. .

As shown in fig. 4, the substrate electrode 41 and the diaphragm electrode 51 may form a capacitance structure of the sensor, and the utility model also adopts a boundary structure formed by combining boundary rings of the annular substrate electrode 41 and the annular diaphragm electrode 52, so that the influence of edge effect can be greatly reduced.

As shown in fig. 2 and 4, in some embodiments, the substrate 1 is further provided with a film lead pad a, so as to facilitate the extraction of the film electrode 5 on the film 2 and support the lead.

As shown in fig. 2 and 6, the pressure sensor includes a sealing layer 3, the sealing layer 3 may be disposed on the substrate 1, the material of the sealing layer 3 may be glass paste, the thickness of the sealing layer may be greater than 5 μm, for example, 6 to 30 μm, for example, 6 μm, 8 μm, 10 μm, etc., the sealing layer 3 may be an outer-square-inner-circular structure, the elastic membrane 2 and the side of the substrate 1 printed with the electrode are close to each other and are overlapped, and the sealing layer 3 is disposed between the membrane 2 and the substrate 1 and forms a closed cavity B between the membrane 2 and the substrate 1.

As shown in fig. 2, further, the sealing layer 3 is provided with a first ring 31 at a central area thereof, an area in the first ring 31 may be a pressure sensing deformation area, the diaphragm 2 may sense pressure of the measurement medium to form deformation within the deformation area, and the substrate electrode 41 is disposed in the first ring 31. Furthermore, the sealing layer 3 is further provided with a second ring 32 outside the first ring 31, and the first ring 31 and the second ring 32 form a connection, specifically, the sealing layer 3 has two concentric circles connected, so that the sealing layer with the structure can effectively ensure the tightness, avoid stress concentration as much as possible, and improve the fatigue resistance of the ceramic pressure sensing element.

As shown in fig. 2, further, the sealing layer 3 may entirely cover the substrate 1, i.e. be distributed on one side surface of the substrate 1, and the sealing layer 3 may be provided with a triangular area 33 near a top corner of the substrate 1, and the triangular area 33 may be located at the periphery of the second ring 31.

As shown in fig. 2, 5 and 7, the substrate 1 is provided with through holes (11, 12, 13), the cross section of the through holes (11, 12, 13) may have a funnel structure with thick ends and thin middle, that is, two ends may be round platforms (12 a,12 c) and the middle may be in the shape of a cylinder 12b, the taper of the round platforms (12 a,12 c) may be greater than 1:5, and the diameter of the middle cylinder position of the through holes (11, 12, 13) may be 0.2-1 mm. The through holes (11, 12, 13) may include a lead hole 11 having a ring electrode, a substrate electrode lead hole 12, and a membrane electrode lead hole 13.

As shown in fig. 2 and 5, the through holes (11, 12, 13) may be disposed at one side of the substrate 1, for example, the lead hole 11 of the ring electrode and the lead hole 13 of the membrane electrode may be disposed at two ends, the lead hole 12 of the substrate electrode may be disposed in the middle, further, the lead hole 11 of the ring electrode and the lead hole 13 of the membrane electrode may be disposed outside the first ring 31, further may be disposed in the triangular area 33, and the lead hole 12 of the substrate electrode may be disposed outside the first ring 31 and further may be disposed between the first ring 31 and the second ring 32. The electrode pad is not provided with the substrate electrode, the substrate annular electrode and other electrodes, so that parasitic capacitance of the product can be avoided.

As shown in fig. 4, the circuit principle of the utility model is as follows: the parallel plate capacitor formed by the diaphragm electrode 51 and the substrate electrode 41 is used as a main output signal of pressure, and the parallel plate capacitor formed by the annular diaphragm electrode 52 and the annular substrate electrode 42 is grounded to shield parasitic capacitance, so that the accuracy of capacitance signals is ensured.

The preparation process of the present utility model is exemplified as follows.

As shown in fig. 1 to 7, the pressure sensor is square or octagonal, and the substrate 1 and the diaphragm 2 may be realized by casting or dry-pressing and then sintering. Based on the substrate 1 and the membrane 2, the electrodes are brushed thereon by screen printing, after sintering, the sealing-bonded glass paste is brushed on the substrate 1 again, through holes (lead holes) into which leads (terminals) are to be inserted are exposed, and the glass paste is sintered again to form the sealing layer 3. Then the base plate 1 and the membrane 2 are combined together, the electrode is aligned with the electrode, and then the two are sintered at high temperature again, so that the two are tightly adhered together. A certain pressure is required during sintering to avoid separation of the two ceramic plates. By doping the glass paste with a few high temperature resistant glass beads of a fixed diameter, it is ensured that the glass remains solid when the paste is melted, so that the metal electrode planes are not in contact with each other and a substantially fixed distance is ensured. This also ensures consistency of the sensitive units.

After the substrate 1 and the membrane 2 are assembled, semi-solid conductive slurry can be injected into the lead through hole of the substrate 1, then a terminal is inserted, and the ceramic sensitive unit assembly from which the capacitance signal is led out can be obtained through high-temperature solidification.

The preparation process of the utility model can also be based on a large ceramic plate, after printing electrodes and sealing layers on the ceramic plate, cutting the ceramic plate into small ceramic plates with required sizes, wherein the cutting can be laser cutting, and then repeating the assembly of thin and thick ceramic plates and sintering. Based on the cutting of the ceramic plates in large blocks, the production efficiency can be remarkably improved and the cost can be reduced.

Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value. The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A ceramic capacitive pressure sensor, characterized by: the ceramic capacitance pressure sensor comprises:

a substrate, on which a substrate electrode and a substrate electrode pad connected thereto are disposed;

the membrane is provided with a membrane electrode and a membrane electrode pad connected with the membrane electrode, a substrate electrode lead hole and a membrane electrode lead hole penetrate through the substrate, the substrate electrode pad is positioned on the substrate electrode lead hole, and the membrane electrode pad is positioned on the membrane electrode lead hole;

the sealing layer is arranged between the substrate and the diaphragm, a closed cavity is formed among the substrate, the diaphragm and the sealing layer, the sealing layer comprises a first circular ring and a second circular ring arranged on the periphery of the first circular ring, the closed cavity is positioned in the first circular ring, and the substrate electrode and the diaphragm electrode are positioned in the first circular ring;

wherein: the cross section shape and the size of the substrate are the same as those of the diaphragm, the cross section shape of the substrate and the diaphragm is square or octagonal, the substrate electrode pad and the diaphragm electrode pad are arranged outside the first circular ring, and funnel structures are arranged at the two ends of the cross section of the substrate electrode lead hole and the two ends of the cross section of the diaphragm electrode lead hole.

2. The ceramic capacitive pressure sensor of claim 1 wherein: the sealing layer is fully distributed on one side end face of the substrate, and triangular areas are arranged between the periphery of the second circular ring and the top angle of the substrate.

3. The ceramic capacitive pressure sensor of claim 2 wherein: the substrate is provided with an annular substrate electrode, the annular substrate electrode is connected with an annular substrate electrode pad, and the annular substrate electrode is positioned at the periphery of the substrate electrode.

4. A ceramic capacitive pressure sensor according to claim 3, characterized in that: the membrane is also provided with an annular membrane electrode, the annular membrane electrode is positioned at the periphery of the membrane electrode, the annular membrane electrode is connected with an annular membrane electrode pad, the annular substrate electrode pad and the annular membrane electrode pad are positioned on an annular electrode lead hole, and the annular electrode lead hole is arranged on the substrate.

5. The ceramic capacitive pressure sensor of claim 4 wherein: the distance between the substrate electrode and the annular substrate electrode is smaller than 2mm, and the distance between the diaphragm electrode and the annular diaphragm electrode is smaller than 2mm.

6. The ceramic capacitive pressure sensor of claim 4 wherein: the annular electrode lead hole and the diaphragm electrode lead hole are located outside the first circular ring.

7. The ceramic capacitive pressure sensor of claim 1 wherein: the thickness of the sealing layer is greater than 5 μm.

8. The ceramic capacitive pressure sensor of claim 1 wherein: the taper of the truncated cone in the funnel structure is greater than 1:5.

9. The ceramic capacitive pressure sensor of claim 1 wherein: the thickness of the substrate is 1-10 mm, and the thickness of the membrane is 0.05-1 mm.

10. The ceramic capacitive pressure sensor of claim 1 wherein: the thickness of the substrate electrode is smaller than 10 mu m, and the thickness of the membrane electrode is smaller than 10 mu m.