Metal Sealed Pressure Sensors

Abstract

The present invention provides a metal-sealed pressure sensor, belonging to the technical field of pressure sensors, comprising a housing, a first end having a mounting cavity opening toward the end thereof, and a second end having a through hole connected to the bottom of the mounting cavity; a pressure chip module, comprising an electrically connected interconnection sealing seat and a pressure chip, the outer ring of the interconnection sealing seat having a metal ring, which is welded and sealed in the mounting cavity and blocks the through hole, the pressure chip is arranged on the side of the interconnection sealing seat facing the through hole, and the pressure of the medium to be measured is transmitted to the pressure chip through the through hole; a circuit board, fixedly arranged on the interconnection sealing seat, and interconnected with the pressure chip electrical signal by means of the interconnection sealing seat; a connector, having a first end sealedly connected to the first end of the housing, and a second end opposite to the first end, the first end being electrically connected to the circuit board, and the second end being suitable for external electrical connection. The metal-sealed pressure sensor provided by the present invention adopts metal sealing welding, has good sealing performance for the measuring medium, and has high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors, and in particular to a metal sealed pressure sensor. Background Art

[0002] Common pressure sensor pressure sensitive units include the following technologies: ceramic capacitors, ceramic piezoresistors, sputtered thin films, glass micro-melting, and micro-electromechanical systems (MEMS). Ceramic capacitors / ceramic resistors can only be sealed with O-rings and are not compatible with a variety of pressure media. There is a long-term risk of failure and leakage under certain media (such as refrigerants), and the package volume is large. Glass micro-melting uses glass to sinter the sensing chip onto the diaphragm, which has a complex process and large equipment investment. Sputtered thin films sputter the pressure sensing module onto the base, which has a large equipment investment and high cost, and is not popular. Although the cost of pressure sensors prepared using micro-electromechanical systems is low, this type of pressure sensor currently often uses gold wire bonding technology, which cannot be applied to a variety of media, has a short lifespan, and is more complicated, limiting the wide range of pressure sensors prepared using MEMS technology. Summary of the invention

[0003] The embodiment of the present invention provides a metal sealed pressure sensor, aiming to solve the technical problems existing in the prior art that the pressure sensor cannot be applied to a variety of media, has a short life span and a narrow application range.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: to provide a metal sealed pressure sensor, comprising:

[0005] A housing having a first end adapted to be connected to the outside world and a second end opposite to the first end, wherein the first end has a mounting cavity opening toward an end thereof, and the second end has a through hole communicating with a bottom of the mounting cavity;

[0006] A pressure chip module comprises an electrically connected interconnection sealing seat and a pressure chip; the outer ring of the interconnection sealing seat is provided with a metal ring for sealing and welding at the bottom of the installation cavity, and the lower end surface of the interconnection sealing seat blocks the through hole; the pressure chip is arranged on the lower end surface of the interconnection sealing seat and extends into the through hole;

[0007] A circuit board is fixedly arranged on the upper end surface of the interconnection sealing seat and is interconnected with the pressure chip by means of the interconnection sealing seat;

[0008] A connector having a first end portion sealedly connected to the first end of the shell, and a second end portion opposite to the first end portion; the first end portion is provided with a first terminal electrically connected to the circuit board; the first terminal passes through the body of the connector, and a second terminal suitable for external connection is provided at the second end portion.

[0009] The metal-sealed pressure sensor provided by the embodiment of the present invention is provided with a mounting cavity connected with the through hole on the shell, and the outer ring of the interconnected sealing seat is set as a metal ring. The metal ring is sealed and welded with the mounting cavity in the shell, and the pressure chip is located in the through hole at the bottom of the interconnected sealing seat. On the one hand, it is convenient for the pressure chip to test the pressure of the medium to be tested; on the other hand, the metal ring of the outer ring of the interconnected sealing seat is sealed and welded with the mounting cavity to achieve good medium isolation, which can be compatible with a variety of media and has a long service life, a wide temperature resistance range, and can be applied to a variety of media, with a wide range of applications. And the metal-sealed pressure sensor of the present application has a simple process and low cost.

[0010] In a possible implementation, the interconnected sealing seat includes the metal ring, an insulating seal arranged in the metal ring and integrally formed with the metal ring, and a plurality of metal pins sealed in the insulating seal, one end of the metal pin is electrically connected to the pressure chip, and the other end is electrically connected to the circuit board.

[0011] In some embodiments, the insulating seal is a glass body, and the interconnecting seal seat is prepared by a sintering process.

[0012] In a possible implementation, a plurality of solder balls corresponding to the metal pins are provided on the back of the pressure chip, and the pressure chip is fixedly connected to the interconnection sealing seat by soldering to achieve electrical connection.

[0013] In some embodiments, the metal ring surrounds the outer circumference of the through hole port, and the metal ring is seal-welded to the bottom wall of the mounting cavity.

[0014] Exemplarily, a limiting groove which is connected to the through hole and is used to accommodate the interconnected sealing seat is provided at the bottom of the installation cavity, and the metal ring of the interconnected sealing seat is sealed and welded to the peripheral wall of the limiting groove.

[0015] Exemplarily, the shape of the limiting groove is adapted to the outer shape of the interconnected sealing seat and is at the same height as the interconnected sealing seat.

[0016] In order to facilitate the welding of the metal ring, the shell is a metal shell, and the metal ring is laser sealed and welded to the metal shell.

[0017] The metal sealed pressure sensor provided by the embodiment of the present invention has a metal ring of the outer ring of the interconnected sealing seat and a sealing welding with the mounting cavity in the shell, which can achieve good medium isolation, is compatible with a variety of media, has a long service life, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 is a schematic structural diagram of a metal sealed pressure sensor provided by an embodiment of the present invention;

[0020] Figure 2 is a perspective view of a metal sealed pressure sensor provided by an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of the exploded structure of the metal sealed pressure sensor provided by an embodiment of the present invention;

[0022] Figure 4 is a structural schematic diagram of a pressure chip module of a metal sealed pressure sensor provided in an embodiment of the present invention;

[0023] Figure 5 is a structural schematic diagram of a connector of a metal sealed pressure sensor provided in an embodiment of the present invention;

[0024] Figure 6 is a schematic structural diagram of a housing of a metal sealed pressure sensor provided in an embodiment of the present invention;

[0025] In the figure: 10-housing, 11-first end, 12-second end, 13-mounting cavity, 14-through hole, 20-connector, 21-first end, 22-second end, 23-first terminal, 24-second terminal; 30-interconnection sealing seat, 31-metal ring, 32-insulating sealing member, 33-metal pin, 40-circuit board, 50-pressure chip. DETAILED DESCRIPTION

[0026] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0027] In the embodiment of the present invention, the installation cavity of the housing and the outer metal ring of the interconnected sealing seat are sealed by a metal melting process, thereby achieving medium isolation and sealing, thereby avoiding the use of the pressure sensor being limited and unable to be widely used due to reasons such as sealing failure, large sealing volume, and complex process.

[0028] Please also read Figures 1 to 6 The metal sealed pressure sensor provided by the present invention is now described. The metal sealed pressure sensor comprises: a housing 10, a pressure chip module, a circuit board 40 and a connector 20. The housing 10 has a first end 11 suitable for connecting to the outside world, and a second end 12 opposite to the first end 11. The first end 11 has a mounting cavity 13 with an opening toward its end, and the second end 12 has a through hole 14 connected to the bottom of the mounting cavity 13. The pressure chip module comprises an electrically connected interconnection sealing seat 30 and a pressure chip 50. The outer ring of the interconnection sealing seat 30 is provided with a metal ring 31 for sealing and welding at the bottom of the mounting cavity 13, and the lower end surface of the interconnection sealing seat 30 blocks the through hole 14. The pressure chip 50 is arranged on the lower end surface of the interconnection sealing seat 30 and extends into the through hole 14. The circuit board 40 is fixedly arranged on the interconnection sealing seat 30, and is interconnected with the pressure chip 50 by means of the interconnection sealing seat 30. The connector 20 has a first end 21 sealedly connected to the first end 11 of the housing 10, and a second end 22 opposite to the first end 21. The first end portion 21 is provided with a first terminal 23 electrically connected to the circuit board 40 . The first terminal 23 passes through the body of the connector 20 . The second end portion 22 is provided with a second terminal 24 suitable for external connection.

[0029] In the metal sealed pressure sensor provided by the embodiment of the present invention, the pressure chip 50 is located in the through hole 14 of the shell 10 at the lower part of the interconnected sealing seat 30 and is electrically connected to the interconnected sealing seat 30. The circuit board 40 is arranged on the upper part of the interconnected sealing seat 30, and the electrical connection with the pressure chip 50 is achieved by means of the interconnected sealing seat 30. The metal ring 31 of the outer circle of the interconnected sealing seat 30 is sealed and welded to the installation cavity 13 in the shell 10, thereby achieving medium isolation; the sealing is achieved through the sealed connection between the shell 10 and the connector 20, which ensures that the metal sealed pressure sensor can be applied to a variety of media, has a simple process, a small size, and can be widely used.

[0030] The metal ring 31 of the interconnected sealing seat 30 surrounds the outer periphery of the through hole 14 of the housing 10 , and the metal ring 31 is sealed and welded to the bottom wall of the installation cavity 13 , thereby achieving medium isolation.

[0031] As a signal processing circuit, the circuit board not only needs to realize the signal transmission of the pressure chip 50, but also needs to reduce the occupied space, thereby reducing the volume of the pressure sensor. The present application adopts a U-shaped flexible circuit board 40, which can not only realize signal processing, but also meet the requirement of reducing the occupied space. One end of the U-shaped flexible circuit board 40 is connected to the first terminal of the connector 20 through a soldering process, and the other end is welded to the metal pin 33 on the upper part of the interconnection sealing seat 30 through a soldering process to achieve electrical connection, thereby achieving electrical connection between the U-shaped flexible circuit board 40 and the pressure chip 50. When performing a pressure test, the processing circuit on the circuit board 40 will amplify and compensate the tiny pressure signal received from the pressure chip 50 and then output it, thereby achieving a pressure test.

[0032] As an embodiment, the interconnection seal seat 30 includes, in addition to the outer metal ring 31, an insulating seal 32 which is an integral structure with the metal ring 31 is provided inside the metal ring 31, and a plurality of metal pins 33 which are sealed inside the insulating seal 32. The metal pins 33 are used to be electrically connected to an external circuit. The number of metal pins 33 is set to match the external module to be connected. In the present application, one end of the metal pin 33 is connected to the pressure chip 50, and the other end is electrically connected to the circuit board 40.

[0033] The insulating seal 32 may be a glass body, that is, the middle of the interconnection seal seat 30 is a glass body, and a plurality of metal pins 33 are inlaid in the middle of the glass body. The metal pins 33 penetrate the upper and lower surfaces of the interconnection seal seat 30. The metal pins 33 are used for the conduction of electrical signals. A metal ring 31 is provided on the periphery of the glass body, and the metal ring 31 and the glass body are made by a glass-metal sintering process. The specific manufacturing method is: the glass body in the middle is melted by heating, and the glass is cooled and formed to realize the pin, and finally the glass body and the metal ring 31 are constrained and sealed.

[0034] Existing pressure sensors usually use glass micro-melting to sinter the sensing chip with glass on the diaphragm, which has a complex process and large equipment investment. Alternatively, sputtering thin films is used to sputter the pressure sensing module on the base, which has large equipment investment and high cost, is not easy to be widely used, and has high production costs.

[0035] In order to reduce the volume and cost of the pressure chip on the one hand, and to facilitate the electrical connection between the pressure chip 50 and the circuit board 40 on the other hand, the pressure chip 50 in the embodiment of the present application is a silicon piezoresistive chip made using MEMS technology. The pressure chip 50 made using MEMS technology is not only low in cost but also small in size. In order to facilitate connection with an external circuit, tin balls are planted on the back of the pressure chip 50 for soldering, where the number of tin balls matches the number of metal pins 33. The pressure chip 50 can be directly welded to the metal pins 33 on the interconnection sealing seat 30. Since the pressure chip 50 and the interconnection sealing seat 30 are soldered, and the metal ring 31 of the interconnection sealing seat 30 and the mounting cavity 13 of the housing 10 are welded, all connections are rigid connections, so the sensor can be used in various non-conductive gases and liquids.

[0036] In order to make the metal sealed pressure sensor have better sealing performance, a limiting groove can be provided in the installation cavity 13 of the housing 10 for placing the interconnected sealing seat 30, and a better sealing effect can be achieved. The metal ring 31 of the interconnected sealing seat 30 can be sealed and welded with the peripheral wall of the limiting groove, and the limiting groove can be well welded with the metal ring 31 of the interconnected sealing seat 30, and the sealing performance of the sensor can be improved.

[0037] From the perspective of improving the sealing performance, in order to further improve the welding sealing performance of the limiting groove and the metal ring 31 of the interconnected sealing seat 30, the shape of the limiting groove can be adapted to the outer shape of the interconnected sealing seat 30 and be at the same height as the interconnected sealing seat 30, and the metal ring 31 of the interconnected sealing seat 30 and the peripheral wall of the limiting groove are sealed and welded, which can further improve the sealing performance of the sensor, improve the sealing performance to the measuring medium, and increase the reliability of the test.

[0038] In order to be able to be used in more media, the shell 10 can be made of metal, and the metal ring 31 and the metal shell 10 are laser-sealed and welded, which not only has a wider range of uses but also can further improve the sealing performance.

[0039] In order to better achieve the overall sealing of the pressure sensor, after one end of the connector 20 is inserted into the mounting cavity 13, it can be fixed to the mounting cavity 13 by riveting with the help of a metal cover sleeved outside the connector 20, and then coated with sealant for sealing protection.

[0040] When using this metal sealed pressure sensor, the medium to be measured enters through the through hole 14 and contacts the pressure chip 50 to achieve pressure detection. Since one side of the interconnected sealing seat 30 in this application is welded to the pressure chip 50, and the other side is welded to the mounting cavity 13 in the housing 10 by laser welding, and since the laser welding process belongs to the metal melting sealing process, it can be compatible with a variety of media and has a long service life and a wide temperature resistance range. All connections in the metal sealed pressure sensor are rigid connections, which can be used in various non-conductive gases and liquids, and the metal sealed pressure sensor has a wider range of uses.

[0041] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention; although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A metal sealed pressure sensor, characterized in that: include: The housing has a first end suitable for connecting to the outside world and a second end opposite to the first end, wherein the first end has a mounting cavity opening toward the end thereof, and the second end has a through hole communicating with the bottom of the mounting cavity; a limiting groove penetrating the through hole and used for accommodating an interconnected sealing seat is provided at the bottom of the mounting cavity; A pressure chip module comprises an electrically connected interconnection sealing seat and a pressure chip; the outer ring of the interconnection sealing seat is provided with a metal ring for sealing and welding at the bottom of the installation cavity, and the lower end face of the interconnection sealing seat blocks the through hole; the pressure chip is arranged on the lower end face of the interconnection sealing seat and extends into the through hole; the interconnection sealing seat comprises the metal ring, an insulating seal arranged in the metal ring and forming an integral structure with the metal ring, and a plurality of metal pins sealed in the insulating seal, one end of the metal pin is electrically connected to the pressure chip, and the other end is electrically connected to the circuit board; a plurality of solder balls corresponding to the metal pins are provided on the back of the pressure chip, and the pressure chip is fixedly connected to the interconnection sealing seat by soldering to achieve electrical connection; the metal ring of the interconnection sealing seat is sealed and welded to the peripheral wall of the limiting groove; A circuit board is fixedly arranged on the upper end surface of the interconnection sealing seat and is interconnected with the pressure chip by means of the interconnection sealing seat for electrical signal interconnection; A connector having a first end portion sealedly connected to the first end of the shell, and a second end portion opposite to the first end portion; the first end portion is provided with a first terminal electrically connected to the circuit board; the first terminal passes through the body of the connector, and a second terminal suitable for external connection is provided at the second end portion.

2. The metal sealed pressure sensor according to claim 1, characterized in that: The insulating seal is a glass body, and the interconnecting seal seat is prepared by a sintering process.

3. The metal sealed pressure sensor according to claim 1, characterized in that: The metal ring surrounds the outer circumference of the through hole port, and the metal ring is laser sealed and welded to the bottom wall of the installation cavity.

4. The metal sealed pressure sensor according to claim 1, characterized in that: The shape of the limiting groove is adapted to the outer shape of the interconnecting sealing seat and has the same height as the interconnecting sealing seat.

5. The metal sealed pressure sensor according to claim 1 or 4, characterized in that: The shell is a metal shell, and the metal ring is laser sealed and welded to the metal shell.

6. The metal sealed pressure sensor according to claim 5, characterized in that: One end of the connector is inserted into the installation cavity, and is fixed to the installation cavity by riveting with the help of a metal cover sleeved outside the connector, and sealed with sealant.

7. The metal sealed pressure sensor according to claim 1, characterized in that: The circuit board is a U-shaped flexible circuit board, one wing of which is interconnected with the pressure chip by means of the interconnection sealing seat, and the other wing is connected to the first terminal.

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