Pressure sensor media isolation package structure and method of packaging

Abstract

The application provides a pressure sensor medium isolation packaging structure and a packaging method, and belongs to the technical field of pressure sensors.The structure comprises a shell, a circuit board, a sealing gasket and an end cover.The shell has a first chamber and a second chamber that are in communication with each other, the first chamber is used for storing liquid filler, and the side of the first chamber away from the second chamber is provided with a rubber block used for plugging the liquid filler.The circuit board is arranged at the connection between the first chamber and the second chamber, and the circuit board has a measuring hole in communication with the first chamber.The sealing gasket is arranged between the circuit board and the first chamber, and the sealing gasket has a through hole used for communicating the first chamber and the measuring hole.A pressing block is arranged between the end cover and the circuit board, and the two ends of the pressing block are respectively connected with the end cover and the circuit board.Compared with the prior art, when the pressure of high-pressure liquid is measured, the application can effectively resist the thrust of the high-pressure liquid on the circuit board, avoid sealing failure, and improve the anti-interference ability of the sensor in a high-pressure industrial field.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pressure sensors, and more particularly relates to a pressure sensor medium isolation packaging structure and a packaging method. BACKGROUND

[0002] The medium isolation packaging type pressure sensor is a core component for realizing accurate pressure measurement in the fields of industrial automation, energy exploration, aerospace, etc. Its core function is to physically isolate the measured medium (such as corrosive liquid, high-temperature gas, viscous fluid, etc.) from the internal sensitive elements of the sensor through a special packaging structure, while efficiently transmitting the medium pressure signal. Specifically, this type of sensor blocks the direct contact of the measured medium with the pressure-sensitive chip, signal processing circuit, and other core elements through an isolation layer, which can effectively prevent the medium from corroding, wearing, or damaging the elements at high temperatures, ensuring stable measurement accuracy and long-term working reliability in complex working conditions (such as strong corrosion, high viscosity, and particle-containing medium environment). It is one of the key technologies for expanding the application scenarios of pressure sensors.

[0003] Currently, the existing medium isolation packaging type pressure sensor is typically composed of five core parts: a pressure-sensitive chip, a metal isolation diaphragm, a shell, a signal processing circuit board, and a pressure transmission medium (such as liquid fillers such as silicone oil and fluorine oil). In terms of structural design, the isolation diaphragm is generally made of high-strength metal materials such as stainless steel and titanium alloy, and is fixed to the front end of the shell through laser welding or diffusion welding process to form a closed pressure transmission chamber. The chamber is filled with liquid fillers to uniformly transmit the medium pressure sensed by the isolation diaphragm to the pressure-sensitive chip (such as MEMS piezoresistive chip or capacitive chip) at the rear end of the chamber. The circuit board is fixed to the tail of the shell through screw fastening or epoxy resin potting.

[0004] The inventors have found that in high-pressure liquid measurement scenarios (such as deep sea exploration, oil and gas well fracturing, hydraulic systems, etc.), the measured liquid pressure often exceeds 50 MPa, and in some extreme conditions, it can even reach more than 200 MPa. At this time, the continuous high-pressure load of the liquid medium on the sensor packaging structure will cause significant stress concentration at the key sealing parts: the connection part of the circuit board and the shell is prone to crack or gap increase under high-pressure impact, which destroys the original sealing barrier and is prone to micro-cracks under long-term high-pressure cyclic load, causing the liquid filler to penetrate into the inner cavity of the shell along the cracks. The above sealing failure will cause the liquid filler to directly contact the signal processing circuit or corrode the sensitive chip, causing sensor signal drift, circuit short circuit, and even permanent damage to the chip, which severely restricts the reliability and service life of the medium isolation packaging type pressure sensor in the high-pressure liquid measurement field. SUMMARY

[0005] The application aims to provide a pressure sensor medium isolation packaging structure and a packaging method to solve the technical problem that the existing medium isolation packaging type pressure sensor fails to seal at the connection between the circuit board and the shell due to high pressure when applied to high-pressure liquid measurement, and then the liquid filler leaks into the shell to cause damage and failure of the sensor.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the application is:

[0007] The application provides a pressure sensor medium isolation packaging structure, comprising:

[0008] A shell having a first chamber and a second chamber in communication with each other, the first chamber being used for storing a liquid filler; the first chamber being provided with a rubber block for plugging the liquid filler on the side opposite to the second chamber;

[0009] A circuit board being arranged at the connection between the first chamber and the second chamber, and having a measurement hole in communication with the first chamber for conveying the liquid filler to the measurement end of the pressure sensitive chip;

[0010] A sealing gasket being arranged between the circuit board and the first chamber, and having a through hole for communicating the first chamber and the measurement hole; and

[0011] An end cover being arranged on the side of the circuit board facing the second chamber for closing the second chamber; a pressing block being arranged between the end cover and the circuit board for fixing the circuit board.

[0012] In a possible implementation, the second chamber is provided with a ring table in communication with the first chamber; the circuit board is in contact with the end face of the ring table, and the sealing gasket is arranged between the ring table and the circuit board; and the measurement hole and the through hole are coaxially arranged with the ring table.

[0013] In a possible implementation, the circuit board comprises:

[0014] An upper layer board being in contact with the end face of the ring table, the measurement hole being arranged on the upper layer board, and the pressure sensitive chip being arranged on the side of the upper layer board opposite to the ring table; the sealing gasket being arranged between the upper layer board and the ring table; and

[0015] A lower layer board being sleeved on the outer periphery of the ring table, and having a plurality of guide pins between the upper layer board and the lower layer board; both ends of each guide pin being fixedly connected with the upper layer board and the lower layer board.

[0016] The one end of the pressing block towards the first chamber is connected with the upper layer plate and the lower layer plate.

[0017] In a possible implementation, a positioning structure is arranged between the lower layer plate and the shell.

[0018] In a possible implementation, the positioning structure comprises:

[0019] a convex block arranged on the shell; and

[0020] a clamping slot arranged on the lower layer plate, the convex block being adapted to be embedded in the clamping slot when the lower layer plate is sleeved on the ring table.

[0021] In a possible implementation, the sealing gasket has annular convex portions arranged around the through hole on both upper and lower sides, and the two annular convex portions are respectively embedded in the measuring hole and the first chamber.

[0022] In a possible implementation, the one side of the pressing block towards the first chamber is provided with a avoiding slot for embedding the pressure sensitive chip, and the inner top surface of the avoiding slot is connected with the pressure sensitive chip.

[0023] In a possible implementation, a buffer pad is arranged between the inner top surface of the avoiding slot and the pressure sensitive chip.

[0024] In a possible implementation, an elastic block is arranged between the pressing block and the end cover, and the end cover is adapted to extrude the elastic block to make the elastic block elastically deform when the end cover closes the second chamber, so as to apply an action force to the pressing block for moving towards the circuit board.

[0025] In the embodiment, when the pressure sensor detects the measured medium, the measured medium directly acts on the rubber block in the first chamber, the pressure of the measured medium is transmitted to the liquid filler by the rubber block, and the liquid filler finally applies the pressure to the pressure sensitive chip. The pressure sensitive chip measures the pressure transmitted by the liquid filler, so that the pressure sensor can measure the medium to be measured which has conductivity or corrosiveness.

[0026] The sealing gasket is arranged between the circuit board and the first chamber (part of the shell), and has elastic deformation capability itself, can tightly fill the micro gap between the contact surface of the circuit board and the shell, and forms an initial sealing barrier. At the same time, the through hole on the sealing gasket is only used to connect the first chamber and the measuring hole of the circuit board, so that the liquid filler only enters the measuring end of the pressure sensitive chip through the preset path, and the liquid filler is prevented from seeping out from the non-preset gap (such as the edge gap) between the circuit board and the shell under high pressure. This design directly enhances the sealing reliability of the connection, and reduces the risk of sealing failure caused by uneven contact surface or assembly error.

[0027] The end cover applies continuous and stable axial pressure on the circuit board through the pressing block (the two ends of the pressing block are respectively connected with the end cover and the circuit board), so that the circuit board is tightly pressed to the side of the first chamber of the shell. In the high-pressure liquid measurement scene, the liquid filler in the first chamber will generate outward pressure (i.e. "back pressure") on the sealing gasket, and if the circuit board is not firmly fixed, the sealing gasket may be deformed or displaced under pressure, which will damage the sealing interface. The fixed structure of the pressing block and the end cover offsets the impact of high-pressure liquid on the sealing gasket through mechanical pre-tightening force, so as to ensure that the sealing gasket is always tightly attached to the circuit board and the shell, avoid the separation of the sealing interface or the increase of the gap caused by high pressure, and prevent sealing failure.

[0028] The pressure sensor medium isolation packaging structure provided by the embodiment of the application cooperates to solve the sealing failure problem of the connection between the circuit board and the shell in high-pressure liquid measurement, effectively prevents the liquid filler from leaking into the shell, thereby avoiding the damage and failure of the sensor caused by liquid intrusion, and significantly improves the reliability and service life in high-pressure environment.

[0029] The technical scheme adopted by the application further provides a packaging method based on the pressure sensor medium isolation packaging structure according to any one of the preceding content, comprising the following steps:

[0030] A. The sealing gasket is arranged at the connection between the first chamber and the second chamber, and the through hole is coaxially arranged with the first chamber;

[0031] B. The circuit board is installed in the second chamber, the circuit board is connected with the sealing gasket, and the measuring hole is coaxially arranged with the through hole;

[0032] C. The pressing block is arranged on the side of the circuit board away from the first chamber, and one end of the pressing block is connected with the circuit board;

[0033] D. installing the end cover at the opening of the second chamber, so that the end cover is connected with the other end of the pressing block, to fix the circuit board through the pressing block;

[0034] E. injecting liquid filler into the first chamber, and after the liquid filler fills the first chamber, dropping glue into the side of the first chamber away from the second chamber, and forming the glue block after the glue solidifies, to seal the first chamber.

[0035] The packaging method provided by the embodiment has the same beneficial effects as the pressure sensor medium isolation packaging structure described above, and will not be described here again. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 A perspective structural schematic diagram of the pressure sensor medium isolation packaging structure provided by the embodiment of the present application is shown in the figure.

[0038] Figure 2 A sectional structural schematic diagram of the pressure sensor medium isolation packaging structure provided by the embodiment of the present application is shown in the figure.

[0039] Figure 3 A sectional structural schematic diagram of the shell used by the embodiment of the present application is shown in the figure.

[0040] Figure 4 A perspective structural schematic diagram of the circuit board used by the embodiment of the present application is shown in the figure.

[0041] Figure 5 A perspective structural schematic diagram of the sealing gasket used by the embodiment of the present application is shown in the figure.

[0042] Figure 6 A perspective structural schematic diagram of the sealing gasket used by the embodiment of the present application is shown in the figure. Figure 5 A perspective structural schematic diagram of the sealing gasket used by the embodiment of the present application is shown in the figure.

[0043] Figure 7 A perspective structural schematic diagram of the shell and the circuit board used by the embodiment of the present application is shown in the figure.

[0044] Figure 8 An exploded structural schematic diagram of the pressure sensor medium isolation packaging structure provided by the embodiment of the present application is shown in the figure.

[0045] In the figure, various reference signs represent:

[0046] 1, housing; 11, first chamber; 12, second chamber; 13, ring table; 14, liquid filler; 2, circuit board; 21, upper layer plate; 22, lower layer plate; 23, measuring hole; 24, guide needle; 3, sealing gasket; 31, through hole; 32, annular protrusion; 4, end cover; 5, pressing block; 51, avoiding groove; 52, buffer pad; 6, rubber block; 7, positioning structure; 71, protruding block; 72, clamping groove; 8, elastic block; 9, pressure sensitive chip. DETAILED DESCRIPTION

[0047] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0048] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0049] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0050] In addition, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0051] Please refer to Figures 1 to 8 , the pressure sensor medium isolation packaging structure and packaging method provided by the present application will be described. The pressure sensor medium isolation packaging structure comprises a housing 1, a circuit board 2, a sealing gasket 3 and an end cover 4.

[0052] The housing 1 has a first chamber 11 and a second chamber 12 which are in communication with each other, and the first chamber 11 is used to store a liquid filler 14; the side of the first chamber 11 away from the second chamber 12 is provided with a rubber block 6 for plugging the liquid filler 14.

[0053] The circuit board 2 is arranged at the connection of the first chamber 11 and the second chamber 12, and is used for mounting the pressure-sensitive chip 9; the circuit board 2 has a measuring hole 23 in communication with the first chamber 11, and the measuring hole 23 is used for conveying the liquid filler 14 to the measuring end of the pressure-sensitive chip 9.

[0054] The sealing gasket 3 is arranged between the circuit board 2 and the first chamber 11, and the sealing gasket 3 has a through hole 31 for communicating the first chamber 11 and the measuring hole 23.

[0055] The end cover 4 is located at the side of the circuit board 2 facing the second chamber 12, and is used for closing the second chamber 12; the pressure block 5 is arranged between the end cover 4 and the circuit board 2, and the two ends of the pressure block 5 are respectively connected with the end cover 4 and the circuit board 2, so as to fix the circuit board 2.

[0056] The material of the shell 1 can be adjusted according to the application scene (for example, stainless steel is used to improve corrosion resistance), and the type of the liquid filler 14 can be adjusted (for example, fluorine oil is used to replace silicon oil in a high-temperature environment); the glue block 6 can be made of epoxy resin or silica gel, and is suitable for different curing requirements; the shape of the pressure block 5 can be designed as a stepped shape or a tapered shape, so as to adapt to circuit boards 2 with different thicknesses.

[0057] In the embodiment of the application, when the pressure sensor detects the measured medium, the measured medium directly acts on the glue block 6 in the first cavity, the pressure of the measured medium is transmitted to the liquid filler 14 by the glue block 6, and the liquid filler 14 finally acts the pressure on the pressure-sensitive chip 9; the pressure-sensitive chip 9 measures the pressure transmitted by the liquid filler 14, so that the pressure sensor can measure the medium to be measured which has conductivity or corrosion resistance.

[0058] The sealing gasket 3 is arranged between the circuit board 2 and the first chamber 11 (part of the shell 1), and has elastic deformation capability itself, can tightly fill the micro gaps between the contact surface of the circuit board 2 and the shell 1, and forms an initial sealing barrier. At the same time, the through hole 31 on the sealing gasket 3 is only used for communicating the first chamber 11 and the measuring hole 23 of the circuit board 2, so as to ensure that the liquid filler 14 only enters the measuring end of the pressure-sensitive chip 9 through the preset path, and avoid the liquid filler 14 from seeping out from the non-pre-set gap (such as the edge gap) between the circuit board 2 and the shell 1 under high pressure. This design directly enhances the sealing reliability of the connection, and reduces the risk of sealing failure caused by uneven contact surface or assembly error.

[0059] The end cover 4 applies a continuous and stable axial pressure on the circuit board 2 through the pressing block 5 (the pressing block 5 is connected with the end cover 4 and the circuit board 2 at both ends respectively), so that the circuit board 2 is tightly pressed to the side of the first chamber 11 of the shell 1. In the high-pressure liquid measurement scenario, the liquid filler 14 in the first chamber 11 will generate an outward pressure (i.e. "back pressure") on the sealing gasket 3, which may cause the sealing gasket 3 to be deformed or displaced under pressure, thereby damaging the sealing interface. The fixed structure of the pressing block 5 and the end cover 4 offsets the impact of high-pressure liquid on the sealing gasket 3 through mechanical pre-tightening force, ensuring that the sealing gasket 3 is always tightly attached to the circuit board 2 and the shell 1, avoiding separation or increased gap of the sealing interface caused by high pressure, thereby preventing sealing failure.

[0060] The pressure sensor medium isolation packaging structure provided by the embodiments of the present application cooperatively solves the sealing failure problem of the connection between the circuit board 2 and the shell 1 in high-pressure liquid measurement, effectively prevents the liquid filler 14 from leaking into the shell 1, thereby avoiding damage and failure of the sensor caused by liquid intrusion, and significantly improves the reliability and service life in a high-pressure environment.

[0061] In some embodiments, the above-mentioned second chamber 12 can adopt the structure as shown in Figure 2 and Figure 3 , referring to Figure 2 and Figure 3 , the second chamber 12 is provided with a ring table 13 in communication with the first chamber 11; the circuit board 2 is connected with the end face of the ring table 13, and the sealing gasket 3 is arranged between the ring table 13 and the circuit board 2; and the measurement hole 23 and the through hole 31 are coaxially arranged with the ring table 13.

[0062] The circuit board 2 is connected with the end face of the ring table 13, the sealing gasket 3 is clamped between the ring table 13 and the circuit board 2, and the measurement hole 23 and the through hole 31 are coaxial with the ring table 13. The ring table 13 provides mechanical support for the circuit board 2, and at the same time, through coaxial arrangement, it ensures that the fluid path of the liquid filler 14 from the first chamber 11 to the pressure-sensitive chip 9 through the through hole 31 and the measurement hole 23 is aligned, thereby reducing the flow resistance and leakage risk.

[0063] The height of the ring table 13 can be adjusted according to the thickness of the circuit board 2 (such as increasing the height of the ring table 13 to adapt to a double-layer circuit board 2); the end face of the ring table 13 can be provided with an annular groove for accommodating the edge of the sealing gasket 3, thereby further improving the sealing effect; and the inner diameter of the ring table 13 can be designed in a stepped shape to adapt to measurement holes 23 of different diameters.

[0064] By adopting the above technical scheme, the supporting effect of the ring table 13 improves the rigidity of the connection between the circuit board 2 and the shell 1, and avoids measurement errors caused by deformation of the circuit board 2 due to stress; the coaxial arrangement ensures the centration of the fluid path, reduces the pressure loss during liquid flow, and reduces the leakage risk caused by misalignment of the sealing gasket 3.

[0065] In some embodiments, the above-mentioned circuit board 2 can adopt the structure as shown in Figure 2 、 Figure 4 、 Figure 7 and Figure 8 , the circuit board 2 includes an upper layer board 21 and a lower layer board 22. Figure 2 、 Figure 4 、 Figure 7 and Figure 8 .

[0066] The upper layer board 21 is in contact with the end face of the ring table 13, the measuring hole 23 is arranged on the upper layer board 21, and the pressure sensitive chip 9 is arranged on the side of the upper layer board 21 away from the ring table 13; the sealing gasket 3 is arranged between the upper layer board 21 and the ring table 13.

[0067] The lower layer board 22 is sleeved on the outer periphery of the ring table 13, and a plurality of guide pins 24 are arranged between the lower layer board 22 and the upper layer board 21; both ends of each guide pin 24 are fixedly connected with the upper layer board 21 and the lower layer board 22.

[0068] The end of the pressing block 5 facing the first chamber 11 is in contact with the upper layer board 21 and the lower layer board 22.

[0069] The circuit board 2 is divided into the upper layer board 21 and the lower layer board 22: the upper layer board 21 is in contact with the end face of the ring table 13, the measuring hole 23 is arranged and the pressure sensitive chip 9 is installed, and the sealing gasket 3 is located between the upper layer board 21 and the ring table 13; the lower layer board 22 is sleeved on the outer periphery of the ring table 13 and is fixedly connected with the upper layer board 21 through a plurality of guide pins 24; the pressing block 5 is in contact with the end cap 4 and the upper and lower layer boards 22 at both ends. The layered design makes the upper layer board 21 focus on the pressure measurement function, the lower layer board 22 assists in fixing and signal transmission, and the guide pin 24 realizes the mechanical and electrical connection between the upper and lower layers.

[0070] The number of guide pins 24 can be adjusted according to the signal transmission requirements (such as increasing the number of guide pins 24 to support multi-channel data output); the lower layer board 22 can integrate passive components such as capacitors or resistors, simplifying the external circuit design; an insulating gasket can be additionally arranged between the upper layer board 21 and the lower layer board 22 to avoid signal interference.

[0071] By adopting the above technical scheme, the layered structure reduces the overall thickness of the circuit board 2, adapts to the miniaturization packaging demand; the guide pin 24 connection mode takes into account the mechanical strength and electrical signal transmission stability, and is more resistant to vibration than traditional wire connection; the lower layer board 22 is sleeved on the outer periphery of the ring table 13, further limiting the radial displacement of the circuit board 2 and improving the structural stability.

[0072] In some embodiments, the lower layer plate 22 and the shell 1 described above can adopt the structure as shown in Figure 4 and Figure 7 , referring to Figure 4 and Figure 7 , a positioning structure 7 is arranged between the lower layer plate 22 and the shell 1.

[0073] The relative movement of the lower layer plate 22 and the shell 1 is limited by the positioning structure 7, ensuring that the lower layer plate 22 does not rotate or deviate during assembly or use. The positioning structure 7 can adopt mechanical clamping, pin-hole cooperation, etc., directly acting on the contact part of the lower layer plate 22 and the shell 1.

[0074] The positioning structure 7 can be designed as a positioning pin on the shell 1 and a positioning hole on the lower layer plate 22, or a limiting step on the outer periphery of the shell 1 cooperates with the edge of the lower layer plate 22; for high precision requirements, anti-skid lines can be added on the surface of the positioning structure 7 to increase the friction.

[0075] By adopting the above technical scheme, displacement of the lower layer plate 22 due to vibration or temperature change is avoided, ensuring the stability of the connection of the guide pin 24 and the upper layer plate 21, preventing signal transmission interruption; the assembly process is simplified, the positioning structure 7 is used to realize quick alignment of the lower layer plate 22, and production efficiency is improved.

[0076] In some embodiments, the positioning structure 7 described above can adopt the structure as shown in Figure 4 and Figure 7 , referring to Figure 4 and Figure 7 , the positioning structure 7 includes a protrusion 71 and a clamping groove 72.

[0077] The protrusion 71 is arranged on the shell 1. The clamping groove 72 is arranged on the lower layer plate 22; when the lower layer plate 22 is sleeved on the ring table 13, the protrusion 71 is adapted to be embedded in the clamping groove 72.

[0078] The protrusion 71 is embedded in the clamping groove 72 when the circuit board 2 is assembled, and circumferential positioning is realized by mechanical clamping. The protrusion 71 can be designed as a rectangle or a semicircle, and the shape of the clamping groove 72 is adapted to the protrusion 71, ensuring that the two are closely fitted.

[0079] Multiple protrusions 71 and clamping grooves 72 can be arranged (such as 3 groups uniformly distributed along the outer periphery of the ring table 13), improving the positioning stability; the surface of the protrusion 71 can be designed as a rounded corner, reducing the risk of clamping during assembly; the depth of the clamping groove 72 can be slightly greater than the height of the protrusion 71, reserving an assembly gap to adapt to the size tolerance.

[0080] By adopting the technical scheme, positioning is achieved without additional fasteners, the rigid cooperation of the protrusion 71 and the clamping groove 72 can withstand a large circumferential force, and the rotation of the lower plate 22 relative to the shell 1 is avoided to prevent the guide needle 24 from being bent or broken; positioning is completed through the "insertion" action during assembly, and the operation is convenient.

[0081] In some embodiments, the sealing gasket 3 can adopt the structure as shown in Figure 2 、 Figure 5 and Figure 6 , and as shown in Figure 2 、 Figure 5 and Figure 6 , the upper and lower sides of the sealing gasket 3 are provided with annular protruding portions 32 surrounding the through hole 31, and the two annular protruding portions 32 are respectively embedded in the measurement hole 23 and the first chamber 11.

[0082] The upper and lower sides of the sealing gasket 3 are provided with annular protruding portions 32 surrounding the through hole 31, and the two annular protruding portions 32 are respectively embedded in the measurement hole 23 and the first chamber 11. The annular protruding portion 32 can be designed as a circular ring, which is in close contact with the inner wall of the measurement hole 23 and the first chamber 11 through interference fit, thereby increasing the sealing area and contact pressure.

[0083] The cross-sectional shape of the annular protruding portion 32 can be adjusted to be trapezoidal (to improve embedding stability); the height of the annular protruding portion 32 can be designed according to the thickness of the sealing gasket 3 (for example, a high protruding portion is used for a thin sealing gasket 3 to ensure the embedding depth); and sealing glue can be coated on the surface of the annular protruding portion 32 to further improve the sealing effect.

[0084] By adopting the technical scheme, the annular protruding portion 32 realizes "double sealing" through embedding, which increases the tortuosity of the fluid path compared with a flat sealing gasket 3, effectively preventing the liquid filler 14 from leaking; the interference fit makes the sealing gasket 3 in close contact with the measurement hole 23 and the first chamber 11, and adapts to the size expansion or contraction caused by temperature changes.

[0085] In some embodiments, the pressing block 5 can adopt the structure as shown in Figure 2 and Figure 8 , and as shown in Figure 2 and Figure 8 , the side of the pressing block 5 facing the first chamber 11 is provided with an avoiding groove 51 for embedding the pressure-sensitive chip 9, and the inner top surface of the avoiding groove 51 is in contact with the pressure-sensitive chip 9.

[0086] The size of the avoiding groove 51 is slightly larger than the chip, so that the pressing block 5 does not directly extrude the chip body, and the inner top surface applies a slight pre-tightening force to the chip through contact to prevent the chip from loosening.

[0087] The depth of the avoidance groove 51 can be adjusted according to the thickness of the chip (for example, a deep groove is suitable for a thick chip); the inner top surface can be designed as an arc or a step to adapt to the packaging form of the chip (for example, LCC or SOP packaging); and a buffer material (for example, a polyimide film) can be arranged on the inner wall of the avoidance groove 51 to avoid direct rigid contact between the chip and the pressing block 5.

[0088] By adopting the above technical solution, the avoidance groove 51 provides physical protection for the pressure-sensitive chip 9, preventing mechanical damage to the chip during installation of the pressing block 5; the inner top surface fixes the position of the chip, avoiding the chip from being shaken out of the measuring hole 23, and ensuring the stability of the measurement signal.

[0089] In some embodiments, the avoidance groove 51 described above can adopt a structure as shown in Figure 2 , as shown in Figure 2 , a buffer pad 52 is arranged between the inner top surface of the avoidance groove 51 and the pressure-sensitive chip 9.

[0090] The buffer pad 52 is arranged between the inner top surface of the avoidance groove 51 and the pressure-sensitive chip 9, and the material can be selected from an elastic body such as silicone or fluororubber. The buffer pad 52 absorbs external vibration or impact through elastic deformation, avoiding stress concentration of the chip caused by rigid contact.

[0091] The buffer pad 52 can be designed as a ring shape (only surrounding the edge of the chip) or a sheet shape (covering the surface of the chip) to adapt to different chip sizes; the thickness of the buffer pad 52 can be adjusted according to the vibration intensity (for example, a thick buffer pad 52 is selected for a high-frequency vibration environment); and a conductive buffer pad 52 (for example, carbon fiber filled silicone) can be used to combine the functions of buffering and electromagnetic shielding.

[0092] By adopting the above technical solution, the buffer pad 52 effectively reduces the mechanical stress on the chip, reduces the zero-point drift or linearity error caused by stress; the damping effect of the elastic material attenuates vibration energy, improves the reliability of the sensor in harsh environments; and hard contact between the inner top surface of the pressing block 5 and the chip is avoided, preventing scratches on the surface of the chip or the falling of the solder points.

[0093] In some embodiments, the pressing block 5 described above can adopt a structure as shown in Figure 2 , as shown in Figure 2 Figure 2 , an elastic block 8 is arranged between the pressing block 5 and the end cover 4; when the end cover 4 closes the second chamber 12, the end cover 4 is adapted to press the elastic block 8, causing the elastic block 8 to elastically deform, so as to apply a force to the pressing block 5 to move towards the circuit board 2.

[0094] By adopting the technical scheme, the elastic block 8 (such as a spring, a rubber column or an elastic gasket) is arranged between the pressing block 5 and the end cover 4, the elastic block 8 is elastically deformed when the end cover 4 is installed, the restoring force generated by the elastic deformation is transmitted to the circuit board 2 through the pressing block 5, and the continuous pre-tightening force is formed. The elastic coefficient of the elastic block 8 can be designed according to the fixing requirement, so that the circuit board 2 is stably pressed and excessive deformation is avoided.

[0095] The elastic block 8 can be a disc spring (with high bearing capacity) or a wave-shaped gasket (suitable for small space); a plurality of elastic blocks 8 (such as three elastic blocks) can be uniformly arranged circumferentially along the pressing block 5, so that the pre-tightening force is more uniformly distributed; and the surface of the elastic block 8 can be coated with lubricating grease to reduce the frictional resistance when the end cover 4 is tightened.

[0096] By adopting the technical scheme, the pre-tightening force of the elastic block 8 can compensate for the assembly error (such as the size tolerance of parts) and the structural expansion / contraction caused by temperature change, so that the circuit board 2 is always in close contact with the ring table 13, and sealing failure is avoided; compared with rigid connection, the elastic structure reduces the impact of the end cover 4 on the circuit board 2 during installation, and protects the precision components such as the pressure-sensitive chip 9 and the guide needle 24.

[0097] The technical scheme adopted in the application further provides a packaging method based on the medium isolation packaging structure of the pressure sensor in any one of the foregoing.

[0098] A. The sealing gasket 3 is arranged at the connection between the first chamber 11 and the second chamber 12, and the through hole 31 is coaxially arranged with the first chamber 11.

[0099] B. The circuit board 2 is installed in the second chamber 12, the circuit board 2 is in contact with the sealing gasket 3, and the measuring hole 23 is coaxially arranged with the through hole 31.

[0100] C. The pressing block 5 is arranged on the side of the circuit board 2 away from the first chamber 11, and one end of the pressing block 5 is in contact with the circuit board 2.

[0101] D. The end cover 4 is installed at the opening of the second chamber 12, the end cover 4 is in contact with the other end of the pressing block 5, and the circuit board 2 is fixed through the pressing block 5.

[0102] E. The liquid filler 14 is injected into the first chamber 11, and after the liquid filler 14 fills the first chamber 11, the glue liquid is dripped on the side of the first chamber 11 away from the second chamber 12, and the glue block 6 is formed after the glue liquid is solidified, so as to seal the first chamber 11. The vacuum pouring method can be used to inject the liquid filler 14 (to reduce the residual bubbles); the glue liquid can be ultraviolet curing glue (to shorten the curing time) or heat-conducting glue (to improve the heat dissipation of the chip).

[0103] The flow operation reduces assembly complexity and facilitates batch production; the liquid filler 14 is injected after sealing to avoid contamination or leakage during assembly; the glue block 6 sealing process is simple and reliable, ensuring long-term sealing of the first chamber 11 and prolonging the service life of the sensor.

[0104] The encapsulation method provided by the embodiment has the same beneficial effects as the aforementioned pressure sensor medium isolation encapsulation structure, which will not be described here again.

[0105] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pressure sensor media-isolating package structure, characterized by, The application relates to a pressure sensor, which comprises the following parts: a shell with a first chamber and a second chamber, the first chamber is used for storing liquid filler, the side of the first chamber away from the second chamber is provided with a rubber block used for blocking the liquid filler; a circuit board arranged at the joint of the first chamber and the second chamber, and a pressure sensitive chip is arranged on the circuit board; the circuit board is provided with a measuring hole communicating with the first chamber, and the measuring hole is used for conveying the liquid filler to the measuring end of the pressure sensitive chip; a sealing pad arranged between the circuit board and the first chamber, and the sealing pad is provided with a through hole used for communicating the first chamber and the measuring hole; and an end cover arranged on the side of the circuit board facing the second chamber, and the end cover is used for closing the second chamber, and the end cover is provided with a pressing block used for fixing the circuit board on the side of the end cover facing the circuit board. The second chamber is provided with a ring table, the circuit board is connected with the end face of the ring table, the sealing pad is arranged between the ring table and the circuit board, the first chamber extends along the axial direction of the ring table and communicates with the measuring hole. The circuit board comprises: an upper layer board connected with the end face of the ring table, the measuring hole is arranged on the upper layer board, and the pressure sensitive chip is arranged on the side of the upper layer board away from the ring table; the sealing pad is arranged between the upper layer board and the ring table; and a lower layer board sleeved on the outer periphery of the ring table, and a plurality of guide pins are arranged between the upper layer board and the lower layer board; the two ends of each guide pin are fixedly connected with the upper layer board and the lower layer board; wherein the end of the pressing block facing the first chamber is connected with the upper layer board and the lower layer board. The lower layer board and the shell are provided with a positioning structure. The positioning structure comprises: a convex block arranged on the shell; and a clamping groove arranged on the lower layer board; when the lower layer board is sleeved on the ring table, the convex block is adapted to be embedded in the clamping groove. The two sides of the sealing pad are provided with annular convex parts arranged around the through hole, and the two annular convex parts are respectively embedded in the measuring hole and the first chamber.

2. The pressure sensor media-isolation package structure of claim 1, wherein, The side of the pressing block facing the first chamber is provided with a avoiding groove, the avoiding groove is used for embedding the pressure sensitive chip, and the inner top surface of the avoiding groove is connected with the pressure sensitive chip.

3. The pressure sensor media-isolation package structure of claim 2, wherein, The inner top surface of the avoiding groove and the pressure sensitive chip are provided with a buffer pad. The pressing block and the end cover are provided with an elastic block; when the end cover closes the second chamber, the end cover is adapted to extrude the elastic block, so that the elastic block is elastically deformed to apply an action force to the pressing block to move towards the circuit board. The application further discloses a method for assembling the pressure sensor, which comprises the following steps: A. arranging the sealing pad at the joint of the first chamber and the second chamber, and arranging the through hole coaxially with the first chamber; B. arranging the circuit board in the second chamber, and arranging the measuring hole coaxially with the through hole; and C. arranging the pressing block on the side of the circuit board away from the first chamber, and arranging one end of the pressing block to be connected with the circuit board. ​ 4. The pressure sensor media isolation package structure of claim 3, wherein, ​ 5. The pressure sensor media-isolation package structure of claim 4, wherein, ​ ​ ​ 6. The pressure sensor media-isolation package structure of claim 1, wherein, ​ 7. The pressure sensor media-isolation package structure of claim 1, wherein, ​ 8. The pressure sensor media-isolation package structure of claim 7, wherein, ​ 9. The pressure sensor media-isolation package structure of claim 1, wherein, ​ 10. Packaging method based on the pressure sensor media-isolating packaging structure according to any one of the preceding claims 1 to 9, characterized in that ​ ​ ​ ​ D. installing the end cover at the opening of the second chamber, so that the end cover is in contact with the other end of the pressing block, to fix the circuit board through the pressing block; E. injecting liquid filler into the first chamber, and after the liquid filler fills the first chamber, dropping glue into the side of the first chamber away from the second chamber, and forming the glue block after the glue solidifies, to seal the first chamber.

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