Pressure measuring assembly and manufacturing method thereof

Abstract

The invention discloses a pressure measurement assembly and a manufacturing method, which can measure absolute pressure through a metal diaphragm and simplify the structure and process of the pressure measurement assembly. The pressure measuring assembly comprises a metal elastic body, the metal elastic body comprises a diaphragm extending transversely and a circle of base part which is integrally connected to the edge of the diaphragm and extends towards the back side, and the base part and the back side of the diaphragm define a pressure cavity which is used for containing a pressure medium to be measured and provided with an opening; the insulating layer is arranged on the surface of the forward side of the metal elastomer; the cover covers the central part of the diaphragm from the forward side, is connected to the forward side of the diaphragm through a circle of insulating connecting material, and forms a reference pressure cavity with the diaphragm; the pressure measuring circuit is arranged on the surface of the insulating layer and located in the reference pressure cavity; and the plurality of bonding pads are arranged on the surface of the insulating layer, are positioned outside the reference pressure cavity and are connected to a pressure measuring circuit through a plurality of electric lead-out parts arranged on the surface of the insulating layer.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a pressure measurement component and a manufacturing method thereof. Background Art

[0002] At present, the mainstream piezoresistive pressure sensor is usually coupled to the pressure medium to be measured on one side of a diaphragm, thereby generating corresponding strain, and converting the strain into an electrical signal through a bridge composed of pressure-sensitive resistors on one side of the diaphragm. When the other side is coupled to the atmospheric pressure, the pressure measured is a relative pressure (gauge pressure) with atmospheric pressure as the reference pressure. These diaphragms can be semiconductor diaphragms or metal diaphragms. For semiconductor diaphragms, a vacuum cover can be covered on the other side surface by micromachining to measure the pressure (absolute pressure) of the pressure to be measured relative to the vacuum. However, for metal diaphragms, although the atmospheric pressure can be ignored under normal circumstances because it can be processed as a whole and installed by welding so that the measurable pressure can be as high as tens of MPa, it cannot be ignored if the pressure of the medium to be measured is not too high relative to the atmospheric pressure. If the absolute pressure is measured by a metal diaphragm, a metal cover can only be welded on the other side of the metal diaphragm, and the absolute pressure can be measured by evacuating the inside of the metal cover to a vacuum.

[0003] CN112857635A discloses a metal diaphragm type pressure core, which is provided with a pressure measurement circuit composed of a dielectric layer, a conductive layer and a thick film varistor on the surface of a metal elastic body to measure the pressure of the medium to be measured. If a metal cover is welded on the surface of the metal diaphragm, there will be great difficulties, specifically: when the metal cover is welded to the other side surface of the metal diaphragm, it is difficult to reliably achieve insulation between the metal cover and the metal elastic body, and between the metal cover and the conductive layer. If the electrical signal is led out from the via provided on the metal cover through a longer flexible electrical connector (even if one end of the inner side is welded to the pad before the metal cover is welded to the metal diaphragm), the process is also complicated and still needs to be complicatedly insulated and sealed between the lead and the metal cover. In addition, if welding is carried out in a vacuum environment to make the reference pressure chamber vacuum, such welding process has high requirements and high cost. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present application provides a pressure measurement component to solve at least one aspect of the above technical defects.

[0005] To achieve the above objectives, the present application provides the following technical solution: a pressure measurement component, comprising:

[0006] The metal elastic body comprises a diaphragm extending transversely and a base portion integrally connected to the edge of the diaphragm and extending toward the back side, wherein the base portion and the back side of the diaphragm enclose a pressure chamber having an opening for accommodating a pressure medium to be measured;

[0007] An insulating layer disposed on the surface of the positive side of the metal elastic body;

[0008] A cover is provided to cover the central part of the diaphragm from the positive side, the cover is connected to the positive side of the diaphragm through a circle of insulating connecting material and forms a reference pressure chamber with the diaphragm;

[0009] A pressure measurement circuit disposed on the surface of the insulating layer and located inside the reference pressure chamber;

[0010] and a plurality of pads disposed on the surface of the insulating layer and located outside the reference pressure cavity, which are connected to the pressure measurement circuit through a plurality of electrical lead-out portions disposed on the surface of the insulating layer.

[0011] Preferably, the pressure measurement circuit includes a plurality of piezoresistors and an electrical connection portion for configuring the piezoresistors as a Wheatstone bridge.

[0012] Preferably, the varistor is a thick film varistor, which is sintered on the positive side surface of the insulating layer.

[0013] Preferably, the cover is made of ceramic or glass.

[0014] Preferably, the insulating layer is a first glass material sintered on the front side surface of the diaphragm.

[0015] Preferably, the insulating connection material is a sintered second glass material, and the cover is sealed and fixed to the insulating layer and the positive side of the electrical lead-out portion through the sintered second glass material.

[0016] Preferably, the base is provided with an exhaust channel having one end connected to the reference pressure chamber and the other end connected to the outer wall of the base, and an outer end of the exhaust channel is sealed by a sealing body.

[0017] The present invention also claims a method for manufacturing a pressure measuring assembly, which comprises:

[0018] A metal elastic body is provided, the metal elastic body comprising a diaphragm extending laterally and a base portion integrally connected to the edge of the diaphragm and extending toward a back side, the base portion and the back side of the diaphragm enclose a pressure chamber having an opening for accommodating a pressure medium to be measured;

[0019] An insulating layer is manufactured by coating a layer of first glass paste on the positive side surface of the metal elastic body, drying the first glass paste, and sintering the first glass paste;

[0020] A conductive layer is prepared by coating a conductive paste on the surface of the insulating layer, drying the conductive paste, and sintering the conductive paste, wherein the conductive layer includes an electrical connection portion, a plurality of electrical lead portions, and a plurality of pads;

[0021] A plurality of thick film varistors are manufactured on the surface of the insulating layer by coating thick film varistor slurry, drying and sintering processes, wherein the thick film varistors are connected to the electrical connection portion to form a pressure measurement circuit for measuring the pressure of the pressure medium to be measured in the pressure chamber, and the pad is electrically connected to the pressure measurement circuit through the electrical lead-out portion;

[0022] Disposing a layer of glass frit on at least one band-shaped region on the insulating layer that spans the electrical lead-out portion;

[0023] A ceramic cover is positioned to cover the pressure measuring circuit from the positive side so that a circle of connecting plane at the reverse end of the cover that is adapted to the shape and size of the strip-shaped area contacts the glass material, and then the glass material is sintered so that the obtained second glass material can seal and fix the cover on the strip-shaped area so that the cover and the metal elastomer form a reference pressure cavity.

[0024] Preferably, in the above manufacturing method, the base is also provided with an exhaust channel having one end connected to the reference pressure chamber and the other end connected to the side outer wall or the bottom outer wall of the base; the pressure measurement component manufacturing method also includes: after the pressure in the reference pressure chamber is set to a preset pressure, a sealing body is sealed to the outer end of the exhaust channel.

[0025] Preferably, in the above manufacturing method, the glass frit also covers at least a portion of the pressure measurement circuit and / or at least a portion of the portion of the electrical lead-out portion located in the reference pressure chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a longitudinal sectional view of the pressure measurement assembly of the first embodiment;

[0027] Figure 2 A top view of a portion of the structure of the pressure measurement assembly of the first embodiment;

[0028] Figure 3 for Figure 1 An enlarged view of the part A shown in FIG.

[0029] Figure 4 is a three-dimensional diagram of a pressure measurement assembly according to a second embodiment;

[0030] Figure 5 The pressure measuring assembly of the second embodiment is Figure 4 A cross-sectional view of BB shown;

[0031] Figure 6 A top view of a partial structure of a pressure measurement assembly according to a second embodiment;

[0032] Figure 7 A three-dimensional diagram of a partial structure of a pressure measurement assembly according to a second embodiment;

[0033] Explanation of the reference numerals: 100, pressure sensor; 110, pressure chamber; 11, diaphragm; 12, base; 13, connection part; 14, insulating layer; 151, electrical connection part; 152, electrical lead-out part; 153, pad; 15a, varistor; 15b, varistor; 15, pressure measurement circuit; 16, positioning groove; 17a, transverse channel; 17b, longitudinal channel; 17c, inner end; 17d, outer end; 17, exhaust channel; 1, metal elastomer; 20, reference pressure chamber; 22, longitudinal extension part; 2, cover; 3, insulating connection material; 4, external connection lead; 5, sealing body; 141, first part; 142, second part; 21, transverse extension part; 22, longitudinal extension part; 23, straight part. DETAILED DESCRIPTION

[0034] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. The following embodiments are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present application. In the following description, the same symbols are used to represent the same or equivalent elements, and repeated descriptions are omitted.

[0035] In the description of the present application, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present application are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] It should be further understood that the term “and / or” used in the specification and corresponding claims of this application refers to any and all possible combinations of one or more of the listed items.

[0038] See also Figure 1 , Figure 2 . In the first embodiment of the present invention, the pressure measurement assembly includes a metal elastic body 1. The metal elastic body 1 includes a transversely extending diaphragm 11 and a circle of base 12 integrally connected to the edge of the diaphragm 11 and extending toward the back side. The base 12 and the back side of the diaphragm 11 enclose a pressure chamber 110 for accommodating the pressure medium to be measured and having an opening. Among them, the front side of the base 12 and the front side of the diaphragm 11 are preferably located on the same transverse plane, and it has a greater thickness in the longitudinal direction than the diaphragm 11, so that it has greater rigidity relative to the diaphragm 11, so that when the diaphragm 11 is subjected to the medium pressure from the back side, the strain on the front side of the base 12 can be ignored relative to the strain on the front side of the diaphragm 11. Among them, the radial inner part of the back side end of the base 12 can continue to extend downward to form a connecting portion 13 connected to an external element.

[0039] Among them, a circular insulating layer 14 is provided on the surface of the positive side of the metal elastic body 1, and a pressure measurement circuit 15 is provided on the surface of the insulating layer 14. The pressure measurement circuit 15 may include two piezoresistors 15a and two piezoresistors 15b and an electrical connection portion 151. The four piezoresistors are configured as a full-bridge Wheatstone bridge by the electrical connection portion 151, wherein two piezoresistors 15a are located in a low-strain region, and the other two piezoresistors 15b are located in a high-strain region (closer to the center of the diaphragm 11 than the low-strain region). In this way, when the pressure medium to be measured in the pressure chamber 110 applies a certain amount of pressure to the diaphragm, the Wheatstone full bridge outputs a corresponding electrical signal under the drive of the power supply. For example, the Wheatstone full bridge is electrically connected to the outside through four (the number of which is related to the structure of the pressure measurement circuit) electrical lead portions 152 provided on the surface of the insulating layer 14, wherein two electrical lead portions 152 are connected to both ends of the power supply, and the other two electrical lead portions 152 output electrical signals. In some other schemes, the pressure measurement circuit 15 can also be any other suitable structure, for example, it can include two Wheatstone half bridges combined together, and the two varistors 15a therein can also be arranged on other components instead of the front side of the metal elastic body 1, so that the resistance change thereof is zero. The above-mentioned varistor can be a thick film varistor, or a metal strain gauge or a silicon strain gauge, etc. In this embodiment, the varistor is preferably a thick film varistor, which can be sintered on the front side surface of the insulating layer 14.

[0040] The pressure measurement assembly of this embodiment further comprises a cover 2. The cover 2 covers the central part of the diaphragm 11 from the positive side, and is connected by a circle of insulating connecting material 3 (see Figure 3 ) is connected to the positive side of the diaphragm 11 and forms a reference pressure chamber 20 with the diaphragm 11. The pressure measurement circuit 15 is arranged inside the reference pressure chamber 20 to avoid contact with the external environment. The pressure measurement component also includes a plurality of pads 153 arranged on the surface of the insulating layer 14. These pads 153 are located outside the reference pressure chamber 20, and are connected to the pressure measurement circuit 15 inside the reference pressure chamber 20 through the electrical lead-out portion 152, which can be connected to an external device through the external connection lead 4.

[0041] The cover 2 may include a transverse extension portion 21 and a longitudinal extension portion 22 extending from the edge of the transverse extension portion 21 toward one side of the metal elastic body 1, wherein the transverse extension portion 21 may be circular and the longitudinal extension portion 22 may be annular accordingly. The bottom of the longitudinal extension portion 22 is sealed and fixed to the insulating layer 14 and the annular region (not marked) on the positive side of the electrical lead-out portion 152 by a sintered second glass material, and the annular region spans the inner and outer sides of the reference pressure chamber 20 from the electrical lead-out portion 152. The insulating layer 14 is a first glass material sintered on the surface of the positive side of the metal elastic body 1, such as glass or glaze, and may also be organic matter or ceramics, etc., under conditions where the process permits. The insulating connecting material 3 is preferably a sintered second glass material, such as glass or glaze, and in some other schemes, it may also be glue with insulating properties. Among them, the insulating connecting material 3 can cover not only the above-mentioned annular area, but also at least a part of the pressure measurement circuit 15 and / or the electrical lead-out portion 152 located in the reference pressure chamber 20, thereby forming a certain protection for the above-mentioned part of the pressure measurement circuit 15 and / or the electrical lead-out portion 152. In this embodiment, the insulating connecting material 3 can cover the above-mentioned annular area and all of its inner side to form a complete circular area S1.

[0042] The cover 2 may be made of metal, but in this embodiment it is preferably made of ceramic or glass, so that the cover 2 can be better combined with the second glass material.

[0043] Preferably, the base 12 is provided with an exhaust channel 17 having one end connected to the reference pressure chamber 20 and the other end connected to the outer wall of the base 12. An outer end 17d of the exhaust channel 17 is sealed by a sealing body 5. More preferably, at least one longitudinally extending positioning groove 16 can be formed on the outer wall of the base 12 to form a circumferential positioning with an external element or an external device. An outer end 17d of the exhaust channel 17 can be arranged at the bottom of the positioning groove 16 and sealed by a sealing body 5. The sealing body can be a steel ball, which can be fixed and sealed with the base 12 by welding. The exhaust channel 17 can include a transverse channel 17a and a longitudinal channel 17b that are connected. An end of the longitudinal channel 17b away from the transverse channel 17a extends toward the positive side and is connected to the reference pressure chamber 20. An end of the transverse channel 17a away from the longitudinal channel 17b extends transversely to the outer wall of the base 12. In particular, at least one longitudinally extending positioning groove 16 for forming a positioning with an external element is provided on the outer wall of the base 12. An outer end 17 d of the exhaust passage 17 passes through the positioning groove 16 and is sealed by a sealing body 5 .

[0044] The pressure measurement assembly of this embodiment can be obtained by the following manufacturing method:

[0045] A metal elastic body 1 is provided, the metal elastic body 1 comprises a transversely extending diaphragm 11, a circle base 12 integrally connected to the edge of the diaphragm 11 and extending toward the back side; the base 12 and the back side of the diaphragm 11 enclose a pressure chamber 110 having an opening for accommodating a pressure medium to be measured;

[0046] An insulating layer 14 is manufactured by coating a layer of first glass paste on the positive side surface of the metal elastic body 1, drying the first glass paste, and sintering the first glass paste;

[0047] The conductive layer is produced by coating the conductive paste on the surface of the insulating layer 14, drying the conductive paste, and sintering the conductive paste. The conductive layer includes an electrical connection portion 151, a plurality of electrical lead portions 152, and a plurality of pads 153;

[0048] A plurality of thick film varistors are manufactured by coating thick film varistor slurry, drying and sintering on the surface of the insulating layer 14. The thick film varistors are connected to the electrical connection portion 151 to form a pressure measurement circuit for measuring the pressure of the pressure medium to be measured in the pressure chamber 110. The pad 153 is electrically connected to the pressure measurement circuit through the electrical lead portion 152;

[0049] A layer of glass frit is disposed on at least one band-shaped region on the insulating layer 14 that spans the electrical lead-out portion 152;

[0050] A ceramic cover 2 is positioned to cover the pressure measuring circuit from the positive side, so that a circle of connecting planes at the reverse end of the cover 2 that matches the shape and size of the strip-shaped area contacts the glass material. The glass material is then sintered so that the obtained second glass material seals and fixes the cover 2 on the strip-shaped area so that the cover 2 and the metal elastic body 1 form a reference pressure chamber 20;

[0051] Preferably, the base 12 is also provided with an exhaust channel 17, one end of which is connected to the reference pressure chamber 20 and the other end of which is connected to the side outer wall or the bottom outer wall of the base 12. Accordingly, the manufacturing method of the pressure measurement assembly further includes: after the pressure in the reference pressure chamber 20 is set to a preset pressure, a sealing body 5 is sealed to an outer end 17d of the exhaust channel 17. When the pressure in the reference pressure chamber 20 is set to a preset pressure, a protective gas such as nitrogen can be filled into the pressure chamber 110.

[0052] See also Figures 4 to 7 Compared with the first embodiment, the pressure measurement assembly of the second embodiment of the present invention may be changed as follows:

[0053] Unlike the annular longitudinal extension portion 22 in the first embodiment, the longitudinal extension portion 22 of this embodiment has a straight portion 23, which is arranged across the front side of the electrical lead-out portion 152, so that the pads 153 have a larger arrangement space and can be arranged side by side for easy connection with external devices. Accordingly, the insulating connecting material 3 is not covered on the circular area S1, but covers the area S2 composed of the arc-shaped belt-shaped area S21 and the straight belt-shaped area S22.

[0054] Different from the first embodiment in which the outer end 17d of the exhaust channel 17 is arranged on the outer wall of the base 12, the exhaust channel 17 of this embodiment has its outer end 17d directly extending longitudinally to the back surface of the base 12. The back surface of the base 12 can be easily set as a plane, thus making it easier to install the sealing body 5.

[0055] In addition, in this embodiment, the insulating layer 14 may include a substantially annular first portion 141 disposed on the back side of the pressure measurement circuit 15 and the electrical lead-out portion 152, and a second portion 142 disposed on the back side of S2. The insulating layer 14 does not cover the inner end 17c of the exhaust passage 17.

[0056] Similarly, the insulating connecting material 3 of this embodiment, in addition to covering the area S2, can also additionally cover at least a portion of the pressure measurement circuit 15 and / or the electrical lead-out portion 152 located in the reference pressure chamber 20, so that when the connection cover 2 is connected to 1 through the insulating connecting material 3, the portion in the reference pressure chamber 20 can be protected at the same time. More directly, it can cover all other portions except the edge of the insulating layer 14.

[0057] The scope of the disclosure is defined not by the detailed description but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are construed as being included in the disclosure.

Claims

1. A pressure measurement assembly, characterized in that: include: The metal elastic body (1) comprises a diaphragm (11) extending transversely and a base (12) integrally connected to the edge of the diaphragm (11) and extending toward the back side, wherein the base (12) and the back side of the diaphragm (11) enclose a pressure chamber (110) having an opening for accommodating a pressure medium to be measured; An insulating layer (14) disposed on the surface of the front side of the metal elastic body (1); A cover (2) is provided on the central part of the diaphragm (11) from the positive side, connected to the positive side of the diaphragm (11) through a circle of insulating connecting material (3) and encloses a reference pressure chamber (20) with the diaphragm (11); A pressure measurement circuit (15) disposed on the surface of the insulating layer (14) and located inside the reference pressure chamber (20); and a plurality of pads (153) disposed on the surface of the insulating layer (14) and located outside the reference pressure chamber (20), which are connected to the pressure measurement circuit (15) via a plurality of electrical lead-out portions (152) disposed on the surface of the insulating layer (14).

2. The pressure measurement assembly according to claim 1, characterized in that: The pressure measurement circuit (15) includes a plurality of piezoresistors (15a, 15b) and an electrical connection portion (151) for configuring the piezoresistors (15a, 15b) as a Wheatstone bridge.

3. The pressure measurement assembly according to claim 2, characterized in that: The varistor (15a, 15b) is a thick film varistor, which is sintered on the front side surface of the insulating layer (14).

4. The pressure measurement assembly according to claim 1, characterized in that: The cover (2) is made of ceramic or glass.

5. The pressure measurement assembly according to any one of claims 1 to 4, characterized in that: The insulating layer (14) is a first glass material sintered on the front side surface of the diaphragm (11).

6. The pressure measurement assembly according to claim 5, characterized in that: The insulating connection material (3) is a sintered second glass material, and the cover (2) is sealed and fixed to the insulating layer (14) and the positive side of the electrical lead-out portion (152) through the sintered second glass material.

7. The pressure measurement assembly according to claim 1, characterized in that: The base (12) is provided with an exhaust channel (17) having one end connected to the reference pressure chamber (20) and the other end connected to the outer wall of the base (12), and one outer end of the exhaust channel (17) is sealed by a sealing body (5).

8. A method for manufacturing a pressure measurement component, characterized in that: include: A metal elastic body (1) is provided, the metal elastic body (1) comprising a diaphragm (11) extending transversely and a base (12) integrally connected to the edge of the diaphragm (11) and extending toward a reverse side, the base (12) and the reverse side of the diaphragm (11) enclosing a pressure chamber (110) having an opening for accommodating a pressure medium to be measured; An insulating layer (14) is produced by coating a layer of first glass paste on the positive side surface of the metal elastic body (1), drying the first glass paste, and sintering the first glass paste; A conductive layer is produced by coating a conductive paste on the surface of the insulating layer (14), drying the conductive paste, and sintering the conductive paste, wherein the conductive layer comprises an electrical connection portion (151), a plurality of electrical lead portions (152), and a plurality of pads (153); A plurality of thick film varistors are manufactured on the surface of the insulating layer (14) by coating thick film varistor slurry, drying and sintering processes, the thick film varistors are connected to the electrical connection portion (151) to form a pressure measurement circuit for measuring the pressure of the pressure medium to be measured in the pressure chamber (110), and the pad (153) is electrically connected to the pressure measurement circuit through the electrical lead portion (152); A layer of glass material is provided on at least one band-shaped region on the insulating layer (14) that spans the electrical lead-out portion (152); A ceramic cover (2) is positioned to cover the pressure measurement circuit from the positive side so that a circle of connecting planes at the reverse end of the cover (2) that matches the shape and size of the strip-shaped area contacts the glass material, and then the glass material is sintered so that the obtained second glass material seals and fixes the cover (2) on the strip-shaped area so that the cover (2) and the metal elastic body (1) enclose a reference pressure chamber (20).

9. The method for manufacturing a pressure measurement component according to claim 8, characterized in that: The base (12) is also provided with an exhaust channel (17) having one end connected to the reference pressure chamber (20) and the other end connected to the side outer wall or the bottom outer wall of the base (12); the method for manufacturing the pressure measurement component further comprises: after the pressure in the reference pressure chamber (20) is set to a preset pressure, a sealing body (5) is sealed to the outer end of the exhaust channel (17).

10. The method for manufacturing a pressure measurement component according to any one of claims 8 to 9, characterized in that: The glass frit also covers at least a portion of the pressure measurement circuit and / or at least a portion of the portion of the electrical lead-out portion (152) located within the reference pressure chamber (20).

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