CN218724903U

CN218724903U - Ceramic capacitance type pressure sensor

Info

Publication number: CN218724903U
Application number: CN202222906088.6U
Authority: CN
Inventors: 何文超; 何俊; 司敏
Original assignee: Xiaogan Huagong Gaoli Electron Co Ltd
Current assignee: Xiaogan Huagong Gaoli Electron Co Ltd
Priority date: 2022-11-01
Filing date: 2022-11-01
Publication date: 2023-03-24
Anticipated expiration: 2032-11-01

Abstract

The utility model relates to a pressure sensor field, in particular to ceramic capacitance type pressure sensor, including casing, electrical connector, forced induction component and circuit board, the forced induction component is including making up fixed substrate and thin slice together, and the first electrode is established to one side that is close to the thin slice on the substrate, and the second electrode is established to one side that is close to the substrate on the thin slice, and the first shield ring of round is established to first electrode periphery, and round second shield ring is established to second electrode periphery, between first electrode and the first shield ring, all leave the clearance between second electrode and the second shield ring. The utility model discloses a shield ring design can form a shield cover, can shield the parasitic capacitance of the conducting liquid who surveys, and the initial appearance value of protection pressure sensing element ceramic capacitor does not receive the influence of conducting liquid parasitic capacitance such as water to the inaccurate problem of precision when having solved ceramic capacitor formula pressure sensor and having detected conducting liquid pressure such as water has improved the degree of accuracy that pressure sensor detected conducting liquid pressure such as water.

Description

Ceramic capacitance type pressure sensor

Technical Field

The utility model relates to a pressure sensor technical field, in particular to ceramic capacitance type pressure sensor.

Background

Sensor technology is one of the important technologies of modern measurement and automation systems, and almost every technology cannot be separated from a sensor from the process control of production to the life of modern science and technology. The ceramic capacitor type pressure sensor is a common pressure sensor type, and the principle of the ceramic capacitor type pressure sensor is that a substrate and a sheet combination structure is adopted, the sheet is usually fixed with the substrate combination, an electrode pattern is printed on the inner side between the sheet and the substrate combination, so that an initial capacitor is formed, when the medium pressure born by the sheet changes, the capacitance between the sheet and the substrate changes, and the signal is converted and conditioned through a conditioning chip and then output to a later stage for use. The ceramic capacitor technology has the advantages of moderate cost, wide range of measurement, good temperature characteristic, good consistency, good long-term stability and the like, and is widely applied to the fields of automobiles, industrial control and the like.

However, the ceramic capacitive pressure sensor is less directly applied to measuring conductive liquid such as water, and because the conductive liquid such as water has parasitic capacitance, when the conductive liquid such as water is not close to the ceramic capacitor sheet, the initial capacitance between the substrate and the sheet is not affected, and when the conductive liquid such as water is close to the ceramic capacitor sheet, the parasitic capacitance of the conductive liquid such as water is coupled to the initial capacitance, so that the static initial capacitance between the substrate and the sheet is increased, a large deviation occurs in an output signal, and the pressure measurement accuracy on the conductive liquid such as water is inaccurate. In view of the above-mentioned shortcomings, the present invention provides an improvement.

SUMMERY OF THE UTILITY MODEL

In order to overcome the not enough of background art, the utility model provides a ceramic capacitance formula pressure sensor can form a shield cover through adopting the shield ring design, can shield the parasitic capacitance of the conductive liquid who surveys, and the initial capacity value of protection pressure sensing component ceramic electric capacity does not receive the influence of conductive liquid parasitic capacitance such as water to the inaccurate problem of precision when ceramic capacitance formula pressure sensor detects conductive liquid pressure such as water has been solved, the degree of accuracy of ceramic capacitance formula pressure sensor to conductive liquid pressure detection such as water has been improved.

The utility model adopts the technical proposal that: the utility model provides a ceramic capacitance type pressure sensor, includes casing, electric connector, forced induction component and circuit board, the one end of casing has set firmly electric connector forms the installation cavity between casing and the electric connector, install in the installation cavity forced induction component and circuit board are close to electric connector, forced induction component is including the fixed substrate and the thin slice together of combination, and the one side that is close to the thin slice on the substrate is equipped with first electrode, and the one side that is close to the substrate on the thin slice is equipped with the second electrode, the periphery of first electrode is equipped with the first shield ring of round, the periphery of second electrode is equipped with round second shield ring, all leaves the clearance between first electrode and the first shield ring, between second electrode and the second shield ring.

Preferably, the substrate is printed with the first electrode and the first shielding ring, and the sheet is printed with the second electrode and the second shielding ring.

Preferably, the printing is gold paste printing.

Preferably, a sealing ring is arranged between the inner end face of the shell and the sheet, and an installation groove matched with the sealing ring is formed in the inner end face of the shell.

Preferably, the first electrode and the second electrode both comprise a circular pole piece and a leading-out end led out from the circular pole piece, the first shielding ring and the second shielding ring both comprise a circular ring part and a sector part which are connected, the circular ring part surrounds the periphery of the circular pole piece, and the sector part surrounds the periphery of the leading-out end.

Preferably, the diameter of the circular pole piece of the second electrode is greater than that of the circular pole piece of the first electrode, the width of the circular ring part of the first shielding ring is greater than that of the circular ring part of the second shielding ring, and the outer diameter of the circular ring part of the first shielding ring is equal to that of the circular ring part of the second shielding ring.

Preferably, an electrode shielding layer is arranged on one side of the thin sheet far away from the substrate.

Preferably, the substrate and the sheet are fixed together using a glass cement.

Preferably, the circuit board is a flexible circuit board, and a contact pin is arranged in the electrical connector.

Preferably, one end of the shell is of a tubular structure, the other end of the shell is of an open cavity, external threads are arranged on the outer side of the tubular structure, and the pressure sensing element and the circuit board are both installed in the open cavity.

To sum up, the utility model discloses beneficial effect does:

1. the outer sides of the electrode patterns of the ceramic capacitor substrate and the thin sheet of the pressure sensing element are both provided with a circle of shielding ring structure, and a shielding cover is formed by capacitance generated between the two circles of shielding rings to protect an initial capacitance value formed by the first electrode pattern and the second electrode pattern from being influenced by parasitic capacitance of conductive liquid such as water and the like, so that the problem of inaccurate precision when the ceramic capacitor type pressure sensor detects the pressure of the conductive liquid such as water and the like is solved, and the accuracy of the ceramic capacitor type pressure sensor in detecting the pressure of the conductive liquid such as water and the like is improved;

2. the first electrode and the first shielding ring are formed on the substrate by adopting gold paste printing, the second electrode and the second shielding ring are formed on the sheet by adopting gold paste printing, the gold paste printing is convenient to process, the formed electrode pattern is stable and firm, and the product quality can be favorably improved;

3. the electrode is printed on the contact medium surface on the outer side of the sheet to form an electrode shielding layer, after conductive liquid such as water enters the shell, the parasitic capacitance of the medium cannot be directly coupled to the initial capacitance of the pressure sensing element, the influence of the parasitic capacitance is avoided, and the accuracy of pressure detection can be further guaranteed.

The present invention will be further explained with reference to the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive labor.

Fig. 1 is an exploded view of the present invention;

fig. 2 is a schematic cross-sectional view of the present invention;

FIG. 3 is a schematic view of the inner side of the substrate according to the first embodiment of the present invention;

FIG. 4 is a schematic view of the inner side of the thin sheet according to the first embodiment of the present invention;

FIG. 5 is a schematic view of the outer side of the sheet according to the first embodiment of the present invention;

FIG. 6 is a schematic view showing a structure of a second embodiment of the present invention in which an electrode shield layer is provided only on the outer side of a sheet;

the labels in the figure are: 1-shell, 2-electrical connector, 3-pressure sensing element, 4-circuit board, 5-substrate, 6-sheet, 7-first electrode, 8-second electrode, 9-first shielding ring, 10-second shielding ring, 11-sealing ring, 12-circular ring part, 13-sector part, 14-electrode shielding layer, 15-opening cavity and 16-shell thread section.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to fig. 1 to 6 in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In order to make the purpose, technical solution and advantages of the present invention clearer, the following will combine the drawings in the embodiments of the present invention to perform more detailed description on the technical solution in the embodiments of the present invention.

As shown in fig. 1 to 6, the ceramic capacitive pressure sensor disclosed in this embodiment includes a housing 1, an electrical connector 2, a pressure sensing element 3, and a circuit board 4, where the electrical connector 2 is fixedly disposed at one end of the housing 1, a mounting cavity is formed between the housing 1 and the electrical connector 2, the pressure sensing element 3 and the circuit board 4 are mounted in the mounting cavity, and the circuit board 4 is close to the electrical connector 2, the pressure sensing element 3 includes a substrate 5 and a sheet 6 that are fixed together, a first electrode 7 is disposed on one side of the substrate 5 close to the sheet 6, a second electrode 8 is disposed on one side of the sheet 6 close to the substrate 5, a circle of first shielding ring 9 is disposed on the periphery of the first electrode 7, a circle of second shielding ring 10 is disposed on the periphery of the second electrode 8, and gaps are left between the first electrode 7 and the first shielding ring 9 and between the second electrode 8 and the second shielding ring 10. In the above technical scheme, one end of the circuit board 4 is coupled with the pressure sensing element 3 to process and convert the pressure signal, the other end of the circuit board is coupled with the electrical connector 2 to output the pressure signal, the pressure sensing element 3 is composed of the substrate 5 and the sheet 6, the material is a ceramic material, the high and low temperature performance is good, because the inner sides of the substrate 5 and the sheet 6 are printed with electrode patterns, a certain initial capacitance value can be generated, a shielding cover can be formed by adding the first shielding ring 9 and the second shielding ring 10, namely the shielding ring design on the substrate 5 and the sheet 6, the parasitic capacitance of the measured conductive liquid can be shielded, the initial capacitance value of the ceramic capacitance of the pressure sensing element 3 is protected from the influence of the parasitic capacitance of the conductive liquid such as water, and the like, thereby the problem of inaccurate precision when the ceramic capacitive pressure sensor detects the pressure of the conductive liquid such as water is solved, and the accuracy of the ceramic capacitive pressure sensor to detect the pressure of the conductive liquid such as water is improved. When the substrate 5 and the sheet 6 are combined together, an initial capacitance is generated between the first electrode 7 and the second electrode 8 pattern, when a medium pressure acts on the sheet 6, the sheet 6 is deformed, the distance between the substrate 5 and the sheet 6 is changed, a capacitance value is changed, an output voltage is changed due to the changed capacitance value, and the medium pressure is detected. The capacitance can be generated between the first shielding ring 9 and the second shielding ring 10, a shielding cover is formed, the influence of the parasitic capacitance of the conductive liquid can be well shielded, the first shielding ring 9 and the second shielding ring 10 can be known to form a shielding effect as a whole, the shielding effect is good, and the accuracy of the pressure detection of the conductive liquid such as water by the ceramic capacitive pressure sensor can be effectively improved.

Preferably, the substrate 5 is printed with the first electrode 7 and the first shielding ring 9, and the sheet 6 is printed with the second electrode 8 and the second shielding ring 10. In this embodiment, the first electrode 7 and the first shield ring 9 on the substrate 5 are directly printed, and the second electrode 8 and the second shield ring 10 on the sheet 6 are also directly printed, so that the printing process is convenient to process, and the processing can be efficiently performed in large quantities.

Preferably, the printing is performed by gold paste printing. In this embodiment, the substrate 5 is printed with gold paste to form the first electrode 7 and the first shielding ring 9, the sheet 6 is printed with gold paste to form the second electrode 8 and the second shielding ring 10, and the gold paste printing is adopted to facilitate processing, so that the formed electrode pattern is stable and firm, the conductivity is good, and the product quality can be improved.

As a preferable technical solution, a sealing ring 11 is arranged between the inner end surface of the shell 1 and the sheet 6, and an installation groove adapted to the sealing ring 11 is arranged on the inner end surface of the shell 1. In this embodiment, the sealing ring 11 is installed in the installation groove, the sealing ring 11 is an O-shaped sealing ring 11 and is made of a high/low temperature resistant and corrosion resistant material, an isolated medium channel is formed between the casing 1 and the pressure sensing element 3 by the sealing ring 11, so that the flow of an external medium inside the casing 1 can be limited, and the accuracy is prevented from being affected by the interference of the external medium on the electrical connection due to the isolated medium channel.

As a preferred technical solution, the first electrode 7 and the second electrode 8 each include a circular pole piece and a leading end led out from the circular pole piece, the first shielding ring 9 and the second shielding ring 10 each include a circular ring portion 12 and a sector portion 13 connected to each other, the circular ring portion 12 surrounds the circumference of the circular pole piece, and the sector portion 13 surrounds the circumference of the leading end. In this embodiment, lead wire end is drawn forth on the disc can be convenient for connect the lead wire, there is the clearance between two disc pieces, can be convenient for form initial electric capacity, the shield ring can encircle the periphery at the disc piece well through setting up ring portion 12, can encircle the periphery at the end of drawing forth well through setting up sector 13, so both can make first shield ring 9 surround the periphery at first electrode 7 well on the whole, also enable second shield ring 10 surround the periphery at second electrode 8 well, above-mentioned pattern reasonable in design, both be convenient for printing and processing, also enable two shield ring designs to play the shielding effect well, ceramic capacitive pressure sensor has improved the degree of accuracy that electrically conductive liquid pressure such as water detected greatly.

Preferably, the diameter of the circular pole piece of the second electrode 8 is larger than that of the circular pole piece of the first electrode 7, the width of the circular ring part 12 of the first shielding ring 9 is larger than that of the circular ring part 12 of the second shielding ring 10, and the outer diameter of the circular ring part 12 of the first shielding ring 9 is equal to that of the circular ring part 12 of the second shielding ring 10. In this embodiment, the width of the annular portion 12 of the first shielding ring 9 is greater than the width of the annular portion 12 of the second shielding ring 10, so that a part of overlap exists between the first shielding ring 9 and the second electrode 8 (i.e., a part of the area of the first shielding ring may be directly opposite to a part of the area of the second electrode), a capacitor may be generated, and a certain shielding effect may be formed, so as to protect the initial capacitance of the product.

Preferably, an electrode shielding layer 14 is provided on the side of the sheet 6 remote from the substrate 5. In this embodiment, an electrode is printed on the outer side of the sheet 6 contacting the medium to form an electrode shielding layer 14, preferably, the electrode shielding layer 14 is printed with gold paste, after the conductive liquid such as water enters the housing 1, the parasitic capacitance of the medium is not directly coupled to the initial capacitance of the pressure sensing element 3, so that the influence of the parasitic capacitance is avoided, and the accuracy of pressure detection can be further ensured. In a specific implementation, even if no shielding ring is added on the sheet 6, the electrode shielding layer 14 is only printed on the outer side of the sheet 6 to play a certain shielding role, so that the influence of parasitic capacitance of conductive liquid such as water can be eliminated, and the test precision is improved. In the sheet 6 of this embodiment, as shown in fig. 6, the electrode shield layer 14 is printed only on the outer side of the sheet 6 without adding a shield ring to the inner side of the sheet 6.

Preferably, the substrate 5 and the sheet 6 are fixed together by glass cement. In this embodiment, the partial region between the substrate 5 and the sheet 6 is filled with glass cement and then fixed together, and during actual processing, certain requirements are imposed on the thickness of the glass cement, on one hand, the substrate 5 and the sheet 6 can be well bonded together to perform a sealing function, and on the other hand, the distance between the first electrode 7 and the second electrode 8 is controlled through the thickness of the glass cement, so that the size of an initial capacity value is convenient to control.

As a preferred technical solution, the circuit board 4 is a flexible circuit board 4, and a pin is arranged in the electrical connector 2. In this embodiment, the circuit board 4 is a flexible circuit board 4, and is made of PI material, which has high reliability, is an excellent flexible printed circuit board 4, has high wiring density, light weight, thin thickness and good bending property, and can well meet the product requirements and improve the product quality, the pin and the electrical connector 2 of this embodiment are of a sealing and molding integrated structure, and one end of the pin is electrically connected with the flexible circuit board 4 by lead-free soldering.

As a preferred technical solution, one end of the housing 1 is a tubular structure, the other end is an open cavity 15, an external thread is arranged on the outer side of the tubular structure, and the pressure sensing element 3 and the circuit board 4 are both installed in the open cavity 15. In this embodiment, the housing 1 is a metal housing 1, one end of which is a tubular structure, and the outside of the tubular structure is provided with an external thread to form a housing threaded section 16, which can facilitate mechanical connection with the outside, and the other end is an open cavity 15, and the open cavity 15 is used for accommodating the pressure sensing element 3, the flexible circuit board 4 and a part of the electrical connector 2. In specific implementation, the upper edge of the housing 1 forms a bending part for pressing the electrical connector 2.

The fixing manner or the fixing connection manner not described in the embodiment may adopt an existing connection manner according to a specific position, and is not specifically described herein.

The parts not referred to in the present embodiment are the same as or can be implemented by the prior art, and will not be further described here.

The skilled person should understand that: although the present invention has been described according to the above embodiments, the inventive idea is not limited to this embodiment, and any application of the inventive idea is also included in the scope of the present patent right.

Claims

1. A ceramic capacitive pressure sensor, characterized by: including casing, electric connector, forced induction component and circuit board, the one end of casing has set firmly electric connector forms the installation cavity between casing and the electric connector, install in the installation cavity forced induction component and circuit board are close to electric connector, forced induction component is including the fixed substrate and the thin slice together of combination, and the one side that is close to the thin slice on the substrate is equipped with first electrode, and the one side that is close to the substrate on the thin slice is equipped with the second electrode, the periphery of first electrode is equipped with the first shielding ring of round, the periphery of second electrode is equipped with round second shielding ring, all leaves the clearance between first electrode and the first shielding ring, between second electrode and the second shielding ring.

2. The ceramic capacitive pressure sensor of claim 1, wherein: the substrate is printed with the first electrode and the first shielding ring, and the sheet is printed with the second electrode and the second shielding ring.

3. A ceramic capacitive pressure sensor according to claim 2, wherein: the printing adopts gold paste printing.

4. A ceramic capacitive pressure sensor according to claim 1, wherein: and a sealing ring is arranged between the inner end surface of the shell and the sheet, and an installation groove matched with the sealing ring is arranged on the inner end surface of the shell.

5. A ceramic capacitive pressure sensor according to claim 1, wherein: the first electrode and the second electrode both comprise circular pole pieces and leading-out ends led out from the circular pole pieces, the first shielding ring and the second shielding ring both comprise circular ring parts and sector parts which are connected, the circular ring parts are arranged around the peripheries of the circular pole pieces, and the sector parts are arranged around the peripheries of the leading-out ends.

6. The ceramic capacitive pressure sensor of claim 5, wherein: the diameter of the circular pole piece of the second electrode is larger than that of the circular pole piece of the first electrode, the width of the circular ring part of the first shielding ring is larger than that of the circular ring part of the second shielding ring, and the outer diameter of the circular ring part on the first shielding ring is equal to that of the circular ring part on the second shielding ring.

7. A ceramic capacitive pressure sensor according to claim 1, wherein: and an electrode shielding layer is arranged on one side of the thin sheet far away from the substrate.

8. A ceramic capacitive pressure sensor according to claim 1, wherein: the substrate and the sheet are fixed together by glass cement.

9. A ceramic capacitive pressure sensor according to claim 1, wherein: the circuit board adopts the flexible circuit board, be equipped with the contact pin in the electrical connector.

10. A ceramic capacitive pressure sensor according to claim 1, wherein: one end of the shell is of a tubular structure, the other end of the shell is of an open cavity, external threads are arranged on the outer side of the tubular structure, and the pressure sensing element and the circuit board are both installed in the open cavity.