Multi-parameter differential pressure sensor with full-symmetric structure and double-side measurement and use method of multi-parameter differential pressure sensor

Abstract

The invention belongs to the technical field of sensors, and relates to a multi-parameter differential pressure sensor with a full-symmetric structure and double-side measurement and a use method of the multi-parameter differential pressure sensor. The pressure sensor comprises a base, two measuring cavities are formed in the base, silicon piezoresistive chips are arranged in the two measuring cavities, and the two measuring cavities are used for receiving pressure from different pressure sources respectively. Two oil guide channels are formed in the base, one end of each oil guide channel is communicated with one measuring cavity, the other end of each oil guide channel makes contact with the negative pressure side of the silicon piezoresistive chip in the other measuring cavity, in other words, the two silicon piezoresistive chips can achieve high and low pressure measurement of the two measuring cavities, and symmetrical output measurement on physical signals is achieved. The base is provided with two oil filling channels and two pressure guiding channels, and each measuring cavity is communicated with one oil filling channel and one pressure guiding channel. The oil filling channels are used for filling the two measuring cavities with silicone oil, and after silicone oil filling is completed, the two oil filling channels are sealed. The two pressure guiding channels are used for guiding the pressure to be measured into the measuring cavity.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors and relates to a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement and a use method thereof. Background Art

[0002] Differential pressure sensors are sensitive elements that sense the pressure difference between the high and low pressure sides, produce a change in physical quantity, and convert the change in physical quantity into an electrical signal output through power supply excitation.

[0003] Currently known differential pressure sensors mainly include capacitive, piezoresistive and resonant types.

[0004] Among them, the existing silicon piezoresistive sensor has only one differential pressure sensitive element for differential pressure measurement. Although the diaphragm box part of the pressure-inducing structure on both sides of the high / low pressure has a symmetrical structure, Figure 8 As shown, the two sides of the sensitive diaphragm of the silicon piezoresistive chip are not symmetrical structures, and the corresponding signal output is not symmetrical either, so it is not a symmetrical structure in the strict sense.

[0005] At present, silicon piezoresistive chips are generally fixed on the base by gluing, glass micro-melting or anodic bonding. Affected by the bonding material, process and structure, the intrinsic stress of the chip itself and the pressure loss caused by the package are inconsistent when positive and reverse pressure is applied. The corresponding signal output characteristics also vary greatly, such as nonlinearity, hysteresis, repeatability, static pressure influence, temperature drift and other parameter indicators.

[0006] To sum up, the existing sensors have an asymmetric structure and have problems with parameter indicators such as nonlinearity, hysteresis, repeatability, static pressure influence and temperature drift. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-parameter differential pressure sensor with a fully symmetrical structure and bilateral measurement and a method of using the same, so as to solve the technical problems that the existing sensors have an asymmetrical structure, static pressure influence and poor long-term stability. The present invention can achieve symmetrical measurement output on the physical signal, and by effectively utilizing the symmetrical influence at both ends, the sensor can achieve physical compensation and calibration compensation for nonlinearity, hysteresis, repeatability, static pressure influence and temperature drift.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, comprising a base, two measuring cavities are provided on the base, and silicon piezoresistive chips are provided in both measuring cavities; Two oil guide channels are provided on the base, one end of the oil guide channel is connected to one of the measuring cavities, and the other end of the oil guide channel is in contact with the negative pressure side of the silicon piezoresistive chip in the other measuring cavity; Two oil-filling channels and two pressure-inducing channels are arranged on the base, and each measuring cavity is communicated with one oil-filling channel and one pressure-inducing channel.

[0009] Furthermore, a wafer bonding stage, a temperature measuring element and a ceramic insulating cover are provided in the measuring cavity, a wafer bonding stage sintered glass is provided between the wafer bonding stage and the base, a silicon piezoresistive chip is provided on the wafer bonding stage, the silicon piezoresistive chip is located between the wafer bonding stage and the ceramic insulating cover, a first through hole is provided on the wafer bonding stage, the oil guide channel is connected to the negative pressure side of the silicon piezoresistive chip through the first through hole, a plurality of Kovar pins and Kovar glass are pierced on the base, and the silicon piezoresistive chip is connected to the Kovar pins.

[0010] Furthermore, the Kovar pin is connected to the silicon piezoresistive chip and the temperature measuring element by wire bonding, and the Kovar glass is located in the measuring cavity.

[0011] Furthermore, a ceramic insulating pad is provided in the measuring cavity, the ceramic insulating pad is located between the ceramic insulating cover and the wafer bonding platform, and the temperature measuring element is fixedly arranged on the ceramic insulating pad.

[0012] Furthermore, there are a plurality of Kovar glass beads, which are arranged in a ring around the bonding table.

[0013] Furthermore, a flexible circuit board and a ceramic circuit board are provided in the measuring cavity, the flexible circuit board is attached to the ceramic insulating cover, and the Kovar pins are connected to the silicon piezoresistive chip and the temperature measuring element through the flexible circuit board and the ceramic circuit board in sequence.

[0014] Furthermore, a pressure-inducing end cover is provided on the base, and an oil-filling channel and a pressure-inducing channel are provided on the pressure-inducing end cover.

[0015] Furthermore, the base is connected to the fully symmetrical overpressure protection diaphragm box through a connecting sleeve, and two pressure-inducing holes are provided on the fully symmetrical overpressure protection diaphragm box, and the two pressure-inducing holes are respectively connected to the two pressure-inducing channels.

[0016] Furthermore, the fully symmetrical overpressure protection membrane box includes a central protection membrane, a membrane box base is provided on both sides of the central protection membrane, a medium isolation membrane is provided on the membrane box base, a sealing ring is sleeved on the membrane box base, and a pressure-inducing hole is opened on the membrane box base, one end of the pressure-inducing hole is in contact with the central protection membrane.

[0017] Based on the above structure, the present invention also discloses a method for using a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, comprising the following steps: Fill the two measuring cavities in the base with silicone oil through the two oil filling channels, and seal the two oil filling channels; Through two pressure-inducing channels, they are connected to the pressure sources on the high-pressure side and the low-pressure side of the outside world respectively; The pressure signals of the high-pressure side and the low-pressure side of two paths are obtained through two silicon piezoresistive chips; When the pressure signal output on the high-pressure side is greater than the pressure signal output on the low-pressure side, it is judged as positive pressure and the pressure signal output on the high-pressure side is taken; when the pressure signal output on the high-pressure side is less than the pressure signal output on the low-pressure side, it is judged as negative pressure and the pressure signal on the low-pressure side is taken.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention includes a base, and two measuring cavities are provided on the base. Silicon piezoresistive chips are arranged in the two measuring cavities. The two measuring cavities are respectively used to receive pressure from different pressure sources, so as to realize the measurement of pressure difference. Two oil guide channels are provided on the base, one end of which is connected to one of the measuring cavities, and the other end of which is in contact with the negative pressure side of the silicon piezoresistive chip in the other measuring cavity, that is, the two silicon piezoresistive chips can realize the differential pressure measurement of the two measuring cavities, which is used to offset the asymmetric influence of the two ends of the silicon piezoresistive chip, realize the symmetrical output measurement on the physical signal, and is conducive to improving the accuracy of the measurement results, and the pressure measurement has good stability. Two oil filling channels and two pressure induction channels are provided on the base, and each measuring cavity is connected to an oil filling channel and a pressure induction channel. The oil filling channel is used to fill the two measuring cavities with silicone oil, and after the silicone oil is filled, the two oil filling channels are sealed. The two pressure induction channels are used to introduce the pressure to be measured into the measuring cavity. Each measuring cavity is connected to a pressure induction channel, so as to realize the symmetrical output measurement of two different pressure sources.

[0019] 2. The method of the present invention fills the two measuring cavities in the base with silicone oil through two oil-filling channels, seals the two oil-filling channels, and silicone oil, as a medium for transmitting pressure, has good fluidity and stability, and can ensure that the pressure signal is accurately transmitted between the two measuring cavities; through two pressure-inducing channels, it is connected to the pressure sources on the high-pressure side and the low-pressure side of the outside respectively; through two silicon piezoresistive chips, the pressure signals of the two high-pressure sides and the low-pressure side are obtained, and the two silicon piezoresistive chips can realize the high and low pressure measurement of the two measuring cavities, which is used to offset the asymmetric influence of the two ends of the silicon piezoresistive chip. When the pressure signal output on the high-pressure side is greater than the pressure signal output on the low-pressure side, it is determined to be positively pressurized, and the pressure signal output on the high-pressure side is taken. When the pressure signal output on the high-pressure side is less than the pressure signal output on the low-pressure side, it is determined to be negatively pressurized, and the pressure signal on the low-pressure side is taken. By comparing the output sizes of the two pressure signals, the direction and size of the pressure can be accurately determined. The present invention can realize symmetrical measurement output on physical signals, and realize physical compensation and calibration compensation of the sensor for nonlinearity, hysteresis, repeatability, static pressure influence and temperature drift by effectively utilizing the symmetrical influence at both ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the chip coplanar symmetrical packaging of the present invention; Figure 2 is a schematic diagram of the structure of the fully symmetrical overpressure protection membrane box of the present invention, wherein Figure 2 a is a cross-sectional view of a fully symmetrical overpressure protection diaphragm box, where Figure 2 b is the exploded view of the fully symmetrical overpressure protection diaphragm box; Figure 3 It is a schematic structural diagram of the sensitive components of the chip coplanar symmetrical packaging of the present invention; Figure 4 This is a schematic diagram of the structure of the chip coplanar symmetrical packaging base of the present invention, wherein: Figure 4 a. Figure 4 c and Figure 4 e is the side view of the base, Figure 4 b is Figure 4 AA section view of a, Figure 4 d is Figure 4 BB section view of c, Figure 4 f is Figure 4 e CC section view; Figure 5 This is a schematic diagram of the fully symmetrical measurement of the chip coplanar symmetrical packaging sensitive components of the present invention, wherein Figure 5 b. Figure 5 d and Figure 5 f is the side view of the base assembly, Figure 5 a is Figure 5 b DD section view, Figure 5 c is Figure 5 EE cross-sectional view of d, Figure 5 e is Figure 5 FF section view of f; Figure 6 This is a schematic diagram of the structure of the sensitive component of the chip coaxial external pin symmetrical packaging of the present invention, wherein: Figure 6 a is a cross-sectional view of a sensitive component of a chip coaxial external pin symmetrical package, where Figure 6 b is an exploded view of the sensitive components of the chip coaxial external pin symmetrical package; Figure 7 This is a schematic diagram of the structure of the sensitive component of the chip coaxial inner pin symmetrical packaging of the present invention, wherein: Figure 7 a is a cross-sectional view of a sensitive component of a chip coaxial inner pin symmetrical package, where Figure 7 b is an exploded view of the sensitive components of the chip coaxial inner pin symmetrical package; Figure 8 It is a measurement schematic diagram of a silicon piezoresistive differential pressure sensor in the prior art; Fig. 9 The figure is a flow chart of the method of the present invention.

[0021] Among them: 1. Fully symmetrical overpressure protection diaphragm box; 2. Sensitive component; 3. Connecting sleeve; 4. Central protection diaphragm; 5. Diaphragm box base; 6. Dielectric isolation diaphragm; 7. Sealing ring; 8. Base assembly; 9. Base; 10. Adhesive table; 11. Adhesive table sintered glass; 12. Kovar pin; 13. Kovar glass; 14. Oil guide channel; 15. Oil filling channel; 16. Silicon piezoresistive chip; 17. Temperature measuring element; 18. Ceramic insulating pad; 19. Ceramic insulating cover; 20. Pressure-leading assembly; 21. Pressure-leading end cover; 22. Pressure-leading channel; 23. Measuring cavity; 24. Pressure-leading hole; 25. Flexible circuit board; 26. Ceramic circuit board; 27. Sealing steel ball. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 3 , Figure 6 and Figure 7 The present invention discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, including a base 9, two measuring cavities 23 are provided on the base 9, and silicon piezoresistive chips 16 are arranged in the two measuring cavities 23. The two measuring cavities are respectively used to receive pressure from different pressure sources, so as to measure the pressure difference. The silicon piezoresistive chip 16 is used to sense the pressure change in the measuring cavity and convert it into an electrical signal for output.

[0025] Two oil guide channels 14 are provided on the base 9, one end of the oil guide channel 14 is connected to one of the measuring cavities 23, and the other end of the oil guide channel 14 is in contact with the negative pressure side of the silicon piezoresistive chip 16 in the other measuring cavity 23, that is, the two silicon piezoresistive chips 16 can realize the differential pressure measurement of the two measuring cavities 23, which is used to offset the asymmetric influence at both ends of the silicon piezoresistive chip 16, thereby realizing symmetrical output measurement on the physical signal, which is beneficial to improving the accuracy of the measurement results.

[0026] Two oil filling channels 15 and two pressure induction channels 22 are provided on the base 9, and each measuring cavity 23 is connected to an oil filling channel 15 and a pressure induction channel 22. The oil filling channel 15 is used to fill silicone oil into the two measuring cavities 23. After the silicone oil is filled, the two oil filling channels 15 are sealed. The two pressure induction channels 22 are used to introduce the pressure to be measured into the measuring cavity. Each measuring cavity is connected to a pressure induction channel, thereby realizing symmetrical output measurement of two different pressure sources.

[0027] The present invention can realize symmetrical measurement output on physical signals, and realizes physical compensation and calibration compensation of the sensor for nonlinearity, hysteresis, repeatability, static pressure influence and temperature drift by effectively utilizing the symmetrical influence at both ends.

[0028] Embodiment 1: See also Figure 3 , Figure 4 and Figure 5 This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement. The silicon piezoresistive chip 16 is packaged on the same side of the base assembly 8, which is referred to as chip coplanar symmetrical packaging. The details are as follows: The sensitive component 2 includes a base component 8, a silicon piezoresistive chip 16, a temperature measuring element 17, a ceramic insulating pad 18, a ceramic insulating cover 19, and a pressure-inducing component 20. In this example, the base component 8 is composed of a base 9, a bonding platform 10, a bonding platform sintered glass 11, a Kovar pin 12, a Kovar glass 13, an oil-conducting channel 14, and an oil-filling channel 15, and is realized by glass sintering and brazing processes. The pressure-inducing component 20 is composed of a pressure-inducing end cover 21 and a pressure-inducing channel 22, and is realized by brazing processes.

[0029] Two measuring cavities 23 are provided on the base 9, and silicon piezoresistive chips 16 are provided in the two measuring cavities 23; See also Figure 4 and Figure 5 Two oil guide channels 14 are provided on the base 9, one end of the oil guide channel 14 is connected to one of the measuring cavities 23, and the other end of the oil guide channel 14 is in contact with the negative pressure side of the silicon piezoresistive chip 16 in the other measuring cavity 23; See also Figure 4 and Figure 5Two oil filling channels 15 and two pressure-inducing channels 22 are provided on the base 9 , and each measuring cavity 23 is connected to one oil filling channel 15 and one pressure-inducing channel 22 .

[0030] Preferably, see Figure 3 and Figure 5 The measuring cavity 23 is provided with a wafer bonding stage 10, a temperature measuring element 17 and a ceramic insulating cover 19, a wafer bonding stage sintered glass 11 is provided between the wafer bonding stage 10 and the base 9, a silicon piezoresistive chip 16 is provided on the wafer bonding stage 10, and the silicon piezoresistive chip 16 is located between the wafer bonding stage 10 and the ceramic insulating cover 19, a first through hole is opened on the wafer bonding stage 10, and an oil guide channel 14 is connected to the negative pressure side of the silicon piezoresistive chip 16 through the first through hole, a plurality of Kovar pins 12 and Kovar glass pieces 13 are pierced on the base 9, and the silicon piezoresistive chip 16 is connected to the Kovar pins 12.

[0031] Preferably, the Kovar pin 12 is connected to the silicon piezoresistive chip 16 and the temperature measuring element 17 by wire bonding, and the Kovar glass 13 is located in the measuring cavity 23 .

[0032] Preferably, see Figure 3 A ceramic insulating pad 18 is provided in the measuring cavity 23 . The ceramic insulating pad 18 is located between the ceramic insulating cover 19 and the wafer bonding stage 10 . The temperature measuring element 17 is fixedly disposed on the ceramic insulating pad 18 .

[0033] Preferably, there are a plurality of Kovar glass beads 13 , and the plurality of Kovar glass beads 13 are arranged in a circumferential direction of the wafer bonding platform 10 .

[0034] Preferably, see Figure 1 The base 9 is connected to the fully symmetrical overpressure protection diaphragm box 1 through the connecting sleeve 3. The fully symmetrical overpressure protection diaphragm box 1 is provided with two pressure-inducing holes 24, and the two pressure-inducing holes 24 are connected to the two pressure-inducing channels 22 respectively.

[0035] Preferably, see Figure 2 The fully symmetrical overpressure protection diaphragm box 1 includes a central protection diaphragm 4, a diaphragm box base 5 is provided on both sides of the central protection diaphragm 4, a medium isolation diaphragm 6 is provided on the diaphragm box base 5, a sealing ring 7 is sleeved on the diaphragm box base 5, and a pressure-inducing hole 24 is opened on the diaphragm box base 5, and one end of the pressure-inducing hole 24 is in contact with the central protection diaphragm 4.

[0036] Embodiment 2: See also Figure 6 This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement. Two axially symmetrical silicon piezoresistive chips 16 are packaged on both sides of a base 9, and the Kovar pins 12 are led outward at both ends, which is referred to as chip coaxial external pin symmetrical packaging; The base 9 includes two measuring cavities 23, and the two measuring cavities 23 are both provided with silicon piezoresistive chips 16; Two oil guide channels 14 are provided on the base 9, one end of the oil guide channel 14 is connected to one of the measuring cavities 23, and the other end of the oil guide channel 14 is in contact with the negative pressure side of the silicon piezoresistive chip 16 in the other measuring cavity 23; Two oil filling channels 15 and two pressure inducing channels 22 are provided on the base 9 , and each measuring cavity 23 is communicated with one oil filling channel 15 and one pressure inducing channel 22 .

[0037] Preferably, a wafer bonding stage 10, a temperature measuring element 17 and a ceramic insulating cover 19 are provided in the measuring cavity 23, a wafer bonding stage sintered glass 11 is provided between the wafer bonding stage 10 and the base 9, a silicon piezoresistive chip 16 is provided on the wafer bonding stage 10, and the silicon piezoresistive chip 16 is located between the wafer bonding stage 10 and the ceramic insulating cover 19, a first through hole is opened on the wafer bonding stage 10, and an oil guide channel 14 is connected to the negative pressure side of the silicon piezoresistive chip 16 through the first through hole, a plurality of Kovar pins 12 are pierced on the base 9, and the silicon piezoresistive chip 16 is connected to the Kovar pins 12.

[0038] Preferably, a flexible circuit board 25 and a ceramic circuit board 26 are provided in the measuring cavity 23, the flexible circuit board 25 is attached to the ceramic insulating cover 19, and the Kovar pin 12 is connected to the silicon piezoresistive chip 16 and the temperature measuring element 17 through the flexible circuit board 25 and the ceramic circuit board 26 in turn.

[0039] Preferably, see Figure 1 The base 9 is connected to the fully symmetrical overpressure protection diaphragm box 1 through the connecting sleeve 3. The fully symmetrical overpressure protection diaphragm box 1 is provided with two pressure-inducing holes 24, and the two pressure-inducing holes 24 are connected to the two pressure-inducing channels 22 respectively.

[0040] Preferably, see Figure 2 The fully symmetrical overpressure protection diaphragm box 1 includes a central protection diaphragm 4, a diaphragm box base 5 is provided on both sides of the central protection diaphragm 4, a medium isolation diaphragm 6 is provided on the diaphragm box base 5, a sealing ring 7 is sleeved on the diaphragm box base 5, and a pressure-inducing hole 24 is opened on the diaphragm box base 5, and one end of the pressure-inducing hole 24 is in contact with the central protection diaphragm 4.

[0041] Embodiment three: See also Figure 7 This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement. Two axially symmetrical silicon piezoresistive chips 16 are packaged on both sides of a base 9, and the Kovar pins are led out to the middle interior, which is referred to as chip coaxial inner pin symmetrical packaging; The base 9 includes two measuring cavities 23, and the two measuring cavities 23 are both provided with silicon piezoresistive chips 16; Two oil guide channels 14 are provided on the base 9, one end of the oil guide channel 14 is connected to one of the measuring cavities 23, and the other end of the oil guide channel 14 is in contact with the negative pressure side of the silicon piezoresistive chip 16 in the other measuring cavity 23; Two oil filling channels 15 and two pressure inducing channels 22 are provided on the base 9 , and each measuring cavity 23 is communicated with one oil filling channel 15 and one pressure inducing channel 22 .

[0042] Preferably, a wafer bonding stage 10, a temperature measuring element 17 and a ceramic insulating cover 19 are provided in the measuring cavity 23, a wafer bonding stage sintered glass 11 is provided between the wafer bonding stage 10 and the base 9, a silicon piezoresistive chip 16 is provided on the wafer bonding stage 10, and the silicon piezoresistive chip 16 is located between the wafer bonding stage 10 and the ceramic insulating cover 19, a first through hole is opened on the wafer bonding stage 10, and an oil guide channel 14 is connected to the negative pressure side of the silicon piezoresistive chip 16 through the first through hole, a plurality of Kovar pins 12 are pierced on the base 9, and the silicon piezoresistive chip 16 is connected to the Kovar pins 12.

[0043] Preferably, a pressure-inducing end cover 21 is provided on the base 9 , and an oil-filling channel 15 and a pressure-inducing channel 22 are provided on the pressure-inducing end cover 21 .

[0044] Preferably, see Figure 1 The base 9 is connected to the fully symmetrical overpressure protection diaphragm box 1 through the connecting sleeve 3. The fully symmetrical overpressure protection diaphragm box 1 is provided with two pressure-inducing holes 24, and the two pressure-inducing holes 24 are connected to the two pressure-inducing channels 22 respectively.

[0045] Preferably, see Figure 2 The fully symmetrical overpressure protection diaphragm box 1 includes a central protection diaphragm 4, a diaphragm box base 5 is provided on both sides of the central protection diaphragm 4, a medium isolation diaphragm 6 is provided on the diaphragm box base 5, a sealing ring 7 is sleeved on the diaphragm box base 5, and a pressure-inducing hole 24 is opened on the diaphragm box base 5, and one end of the pressure-inducing hole 24 is in contact with the central protection diaphragm 4.

[0046] The present invention arranges a silicon piezoresistive chip 16 on both the high-pressure side and the low-pressure side to achieve completely symmetrical differential pressure measurement, offsetting the static pressure effect and asymmetric time drift caused by the asymmetry on both sides; Through circuit conditioning and software settings, the output signals of the two silicon piezoresistive chips 16 are read simultaneously. When the signal output on the high-pressure side is greater than the signal output on the low-pressure side, it is determined to be positive pressure, and only the output signal of the pressure sensor on the high-pressure side is taken. When the signal output of the sensor on the high-pressure side is less than the signal output on the low-pressure side, it is determined to be negative pressure, and only the output signal of the pressure sensor on the low-pressure side is taken. In this way, only the output signal of the positive pressure force sensor is taken, avoiding the problem of poor linearity of negative pressure on the silicon chip, and achieving symmetrical measurement output on the physical signal; In addition, if other range sensors are placed on the low-pressure side, multi-parameter measurement and compensation can also be achieved.

[0047] In summary, compared with the prior art, the present invention has the following technical effects: A. Completely symmetrical structure, offsetting the asymmetric effects at both ends; B. Dual margin measurement can be achieved on both high and low voltage sides; C. Symmetrical measurement can be achieved on both sides of high / low pressure; D. On both sides of high / low pressure, differential pressure, gauge pressure, static pressure, temperature and full parameter measurement can be achieved; E. On both the high / low voltage sides, modular flexible production and fast delivery can be achieved.

[0048] F. It realizes taking only the positive force output signal of the sensor, avoiding the problem of poor linearity of negative pressure on silicon wafers, and realizing symmetrical output measurement on physical signals.

[0049] Embodiment 4: This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, specifically a chip coplanar symmetrical packaging structure.

[0050] See also Figure 1 , is a schematic diagram of the overall structure of the present embodiment, including a fully symmetrical overpressure protection membrane box 1, a sensitive component 2, and a connecting sleeve 3.

[0051] See also Figure 2 , is a schematic structural diagram of the fully symmetrical overpressure protection diaphragm box 1 of this embodiment, comprising: a central protection diaphragm 4, a diaphragm box base 5, a medium isolation diaphragm 6 and a sealing ring 7.

[0052] See also Figure 3 , is a schematic diagram of the structure of the chip coplanar symmetrical package sensitive component 2 of this embodiment, including: a base component 8, a base 9, a bonding platform 10, a bonding platform sintered glass 11, a Kovar pin 12, a Kovar glass 13, an oil guide channel 14, an oil filling channel 15, a silicon piezoresistive chip 16, a temperature measuring element 17, a ceramic insulating pad 18, a ceramic insulating cover 19, a pressure-leading component 20, a pressure-leading end cover 21 and a pressure-leading channel 22.

[0053] like Figure 1 As shown, the two pressure-inducing channels of the sensitive component 2 are inserted into the pressure-inducing holes 24 of the fully symmetrical overpressure protection membrane box 1 and brazed. Further, the connecting sleeve 3 is welded with the fully symmetrical overpressure protection membrane box 1 and the sensitive component 2 to form an embodiment of the present invention.

[0054] like Figure 2 As shown, the fully symmetrical overpressure protection diaphragm box 1 is composed of a central protection diaphragm 4, two diaphragm box bases 5, and two medium isolation diaphragms 6, which are symmetrically welded together, and then two sealing rings 7 are installed.

[0055] like Figure 3 As shown, the sensitive component 2 is composed of a base component 8, two silicon piezoresistive chips 16, two temperature measuring elements 17, two ceramic insulating pads 18, two ceramic insulating covers 19, and two pressure-inducing components 20. The base component 8 is composed of a base 9, two wafer bonding platforms 10, two wafer bonding platform sintered glasses 11, twelve Kovar pins 12, twelve Kovar glass pieces 13, two oil guide channels 14, and two oil filling channels 15. Among them, two oil guide tubes and two oil filling tubes are brazed together with the base 9, the oil guide tubes are connected to the oil guide channels 14, and the oil filling tubes are connected to the oil filling channels 15, and then the two wafer bonding platforms 10, the twelve Kovar pins 12 are sintered together with the base 9 using two wafer bonding platform sintered glasses 11 and twelve Kovar glass pieces 13. Two ceramic insulating pads 18 are respectively pasted on the bottom surface of the measuring cavity on both sides of the base component 8, and then the two temperature measuring elements 17 are respectively connected to the corresponding four Kovar pins 12 by soldering, and then the two silicon piezoresistive chips 16 are respectively bonded to the two bonding pads 10 and wire-bonded to the corresponding eight Kovar pins 12, and then the ceramic insulating cover 19 is pasted for insulation and filling. The pressure-inducing component 20 is brazed together by the pressure-inducing end cover 21 and the pressure-inducing tube. The pressure-inducing end cover 21 is provided with a pressure-inducing channel 22, and the pressure-inducing tube is connected to the measuring cavity 23 through the pressure-inducing channel 22, and then it is welded together with the aforementioned assembled base component 8, so as to form the sensitive component 2.

[0056] like Figure 4 and Figure 5 As shown, the structure and oil circuit of the base 9 are completely symmetrically designed, with two symmetrical measuring cavities 23, in which two silicon piezoresistive chips 16 are respectively installed. The positive pressure side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the measuring cavity 23, and the negative pressure side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the other measuring cavity 23. One measuring cavity 23 is connected to the negative pressure side of the silicon piezoresistive chip 16 in another measuring cavity 23 through the oil guide channel 14. The positive pressure side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the measuring cavity 23, and the negative pressure side senses the silicone oil pressure in the other measuring cavity 23. The measuring cavity 23 is connected to the left and right pressure sensing chambers of the fully symmetrical overpressure protection membrane box 1 through the pressure inlet channel 22. The entire sensor fills the two measuring cavities 23 with silicone oil through the oil filling channel 15, and the upper end of the oil filling channel is blocked with welding after filling.

[0057] In detail, as an implementation example but not limited to this: 1. If the silicon piezoresistive chips 16 are all designed as differential pressure measurement chips with the same range, symmetrical measurement and compensation of positive and negative pressure differences can be achieved; 2. If one of the silicon piezoresistive chips 16 is a differential pressure chip and the other silicon piezoresistive chip 16 is a gauge pressure chip, the oil guide channel 14 between the measuring cavity 23 where the differential pressure chip is located and the negative pressure side of the gauge pressure chip is blocked, and the differential pressure and gauge pressure measurements can be achieved; 3. If one of the silicon piezoresistive chips 16 is a differential pressure chip and the other silicon piezoresistive chip 16 is an absolute pressure chip, the oil guide channel 14 between the measuring cavity 23 where the differential pressure chip is located and the negative pressure side of the absolute pressure chip is blocked, and the differential pressure and absolute pressure measurements can be achieved; 4. If the silicon piezoresistive chip 16 is designed as a differential pressure measurement chip with different ranges, multi-range measurements can be performed to achieve a larger range scaling ratio.

[0058] Embodiment five: This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, specifically a chip coaxial external pin symmetrical packaging structure; See also Figure 6 a and Figure 6 b, is a sensitive component of the chip coaxial external pin symmetrical package of this embodiment, which is composed of a base 9, a ceramic circuit board 26, a silicon piezoresistive chip 16, a temperature measuring element 17, an FPC flexible circuit board 25, a ceramic insulating cover 19, a pressure-leading end cover 21 and a Kovar pin 12. The base 9 is provided with a chip bonding platform 10, a chip bonding platform sintered glass 11, and a sealing welded steel ball 27. The pressure-leading end cover 21 is provided with an oil filling channel 15, an oil guide channel 14 and a Kovar pin 12. Two sealing welded steel balls 27 are firstly sealed and welded together with the corresponding process holes of the base 9, and then the two chip bonding platforms 10 are sintered together with the base 9 using two chip bonding platform sintered glasses 11. Two ceramic circuit boards 26 are bonded to the bottom surfaces of the two measuring cavities of the base 9, and then two FPC flexible circuit boards 25 are soldered to the two ceramic circuit boards 26 respectively, and then two temperature measuring elements 17 are soldered to the corresponding pads of the ceramic circuit board 26, and then two silicon piezoresistive chips 16 are bonded to the two chip bonding platforms 10 respectively and wire-bonded to the corresponding pads on the ceramic circuit board 26. The pressure-introducing end cover 21 is provided with an oil filling pipe and an oil guide pipe, the oil filling pipe is connected to the oil filling channel 15, and the oil guide pipe is connected to the oil guide channel 14, and then the Kovar pin 12 is sintered with the pressure-introducing end cover 21 using Kovar sintered glass. The Kovar pin 12 is soldered with the FPC flexible circuit board 25, and then the ceramic insulation cover 19 is pasted on the pressure-introducing end cover 21, and then welded with the aforementioned assembled base 9 to form a sensitive component of the chip coaxial external pin symmetrical package of this embodiment.

[0059] like Figure 6As shown in FIG. 2 , the structure and oil circuit of the base 9 are completely symmetrically designed, with two symmetrical measuring cavities 23, each of which is equipped with a silicon piezoresistive chip 16. The positive pressure side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the measuring cavity 23, and the negative pressure side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the other measuring cavity 23. The measuring cavity 23 is connected to the negative pressure side of the silicon piezoresistive chip 16 in the other measuring cavity 23 through the oil guide channel 14, so that double-sided measurement can be achieved.

[0060] Silicone oil is respectively filled into the two measuring chambers 23 through the oil filling passage 15, and after filling, the two oil filling passages 15 are sealed and welded. The oil guide passage 14 is used for connecting the pressure to be measured.

[0061] Embodiment six: This embodiment discloses a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, specifically a chip coaxial inner pin symmetrical packaging structure.

[0062] See also Figure 7 a and Figure 7 b, is a sensitive component 2 with coaxial external pins symmetrically packaged on the chip, which is composed of a base 9, a silicon piezoresistive chip 16, a temperature measuring element 17, a ceramic insulating pad 18 and a ceramic insulating cover 19, a pressure-leading end cover 21 and other components. The base 9 is provided with a Kovar pin 12, a Kovar glass 13, a chip bonding platform 10, a chip bonding platform sintered glass 11, and a sealing welded steel ball 27. The pressure-leading end cover 21 is provided with an oil filling channel 15 and an oil guide channel 14. Two sealing welded steel balls 27 are first sealed and welded with the corresponding process holes of the base 9, and then the twelve Kovar pins 12, two chip bonding platforms 10 are sintered with the base 9 using twelve Kovar glass 13, two chip bonding platform sintered glass 11. Two ceramic insulating pads 18 are bonded to the bottom surfaces of the two measuring cavities 23 of the base 9, and then the two temperature measuring elements 17 are respectively connected to the corresponding four Kovar pins 12 by soldering, and then the two silicon piezoresistive chips 16 are respectively bonded to the two chip bonding platforms 10 and wire-bonded to the corresponding eight Kovar pins 12. The pressure lead end cover 21 is provided with an oil filling channel 15 and an oil guide channel 14. The ceramic insulating cover 19 is bonded to the pressure lead end cover 21, and then the pressure lead end cover 21 and the previously assembled base 9 are welded together to form a sensitive component of the chip coaxial external pin symmetrical package of this embodiment.

[0063] like Figure 7 As shown in FIG. 2 , after the sensor assembly is packaged, two measuring cavities 23 are formed, and silicone oil is filled in the oil filling channel 15, and then the oil filling channel 15 is sealed and welded. The front side of the silicon piezoresistive chip 16 senses the silicone oil pressure in the measuring cavity 23, and the back side of the silicon piezoresistive chip 16 senses the silicone oil pressure of the silicon piezoresistive chip 16 in another measuring cavity 23 through the oil guide channel 14. In this way, double-sided measurement can be achieved.

[0064] Based on this, the sensor of the present invention arranges a differential pressure chip with the same range on both sides of the high and low pressure, respectively, to achieve differential pressure measurement with symmetrical output of two-way signals. Moreover, this symmetry realizes redundant measurement, which can offset the asymmetric effect of the two ends, or selectively ignore it, and selectively output from the two-way signal through software settings.

[0065] Preferably, sensitive elements with different ranges are designed on both sides, so that multi-range measurement applications can be realized on one product. As an example, if the high-pressure side range is 20kPa and the low-pressure side range is 3kPa, accurate measurement of two ranges can be achieved, which is particularly advantageous in application conditions that require high reading accuracy over a wide range. You can also select the main measurement end in the software to determine which range to use based on different measurement ranges.

[0066] If different types of sensitive components are packaged on both sides, multi-parameter measurement and application can be achieved, including temperature, differential pressure, gauge pressure and absolute pressure. For example, if a differential pressure silicon chip is packaged on the high-pressure side and a static pressure silicon chip and a temperature component are packaged on the low-pressure side, a multi-parameter method can be achieved.

[0067] It should be noted that the core of the present invention is the symmetrical measurement of two-way sensitive elements in the high-pressure and low-pressure directions, and is not limited to the above specific embodiments. All equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0068] Based on the above structure, the present invention also discloses a method for using a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, see Fig. 9 , including the following steps: S1, fill the two measuring chambers 23 in the base 9 with silicone oil through the two oil filling channels 15, and seal the two oil filling channels 15. Silicone oil, as a medium for transmitting pressure, has good fluidity and stability, and can ensure that the pressure signal is accurately transmitted between the two measuring chambers; S2, connected to the pressure sources on the high-pressure side and the low-pressure side of the outside world through two pressure-inducing channels 22; S3, two pressure signals of the high-pressure side and the low-pressure side are obtained through two silicon piezoresistive chips 16. Both silicon piezoresistive chips 16 can realize high and low pressure measurement of two measuring cavities 23, which is used to offset the asymmetric effect at both ends of the silicon piezoresistive chip 16.

[0069] S4, when the pressure signal output on the high-pressure side is greater than the pressure signal output on the low-pressure side, it is determined to be positive pressure, and the pressure signal output on the high-pressure side is taken. When the pressure signal output on the high-pressure side is less than the pressure signal output on the low-pressure side, it is determined to be negative pressure, and the pressure signal on the low-pressure side is taken. By comparing the output sizes of the two pressure signals, the direction and size of the pressure can be accurately determined.

[0070] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement, characterized in that: It comprises a base (9), two measuring cavities (23) are provided on the base (9), and silicon piezoresistive chips (16) are provided in the two measuring cavities (23); Two oil guide channels (14) are provided on the base (9), one end of the oil guide channel (14) is in communication with one of the measuring cavities (23), and the other end of the oil guide channel (14) is in contact with the negative pressure side of a silicon piezoresistive chip (16) in the other measuring cavity (23); Two oil-filling channels (15) and two pressure-inducing channels (22) are provided on the base (9), and each measuring cavity (23) is in communication with one oil-filling channel (15) and one pressure-inducing channel (22).

2. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 1 is characterized in that: The measuring cavity (23) is provided with a wafer bonding platform (10), a temperature measuring element (17) and a ceramic insulating cover (19); a wafer bonding platform sintered glass (11) is provided between the wafer bonding platform (10) and the base (9); a silicon piezoresistive chip (16) is provided on the wafer bonding platform (10); the silicon piezoresistive chip (16) is located between the wafer bonding platform (10) and the ceramic insulating cover (19); a first through hole is provided on the wafer bonding platform (10); an oil guide channel (14) is connected to the negative pressure side of the silicon piezoresistive chip (16) through the first through hole; a plurality of Kovar pins (12) and Kovar glass pieces (13) are provided on the base (9); and the silicon piezoresistive chip (16) is connected to the Kovar pins (12).

3. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 2 is characterized in that: The Kovar pin (12) is connected to the silicon piezoresistive chip (16) and the temperature measuring element (17) by wire bonding.

4. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 3 is characterized in that: A ceramic insulating pad (18) is provided in the measuring cavity (23), the ceramic insulating pad (18) is located between the ceramic insulating cover (19) and the wafer bonding platform (10), and the temperature measuring element (17) is fixedly arranged on the ceramic insulating pad (18).

5. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 4 is characterized in that: There are a plurality of Kovar glass beads (13), and the plurality of Kovar glass beads (13) are arranged in a ring in the circumferential direction of the film bonding platform (10).

6. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 2 is characterized in that: A flexible circuit board (25) and a ceramic circuit board (26) are provided in the measuring cavity (23); the flexible circuit board (25) is attached to the ceramic insulating cover (19); and the Kovar pin (12) is connected to the silicon piezoresistive chip (16) and the temperature measuring element (17) in sequence through the flexible circuit board (25) and the ceramic circuit board (26).

7. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 2 is characterized in that: The base (9) is provided with a pressure-inducing end cover (21), and the pressure-inducing end cover (21) is provided with an oil-filling channel (15) and a pressure-inducing channel (22).

8. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 1 is characterized in that: The base (9) is connected to the fully symmetrical overpressure protection diaphragm box (1) via a connecting sleeve (3); the fully symmetrical overpressure protection diaphragm box (1) is provided with two pressure-inducing holes (24), and the two pressure-inducing holes (24) are respectively connected to the two pressure-inducing channels (22).

9. The multi-parameter differential pressure sensor with fully symmetrical structure and double-sided measurement according to claim 8 is characterized in that: The fully symmetrical overpressure protection diaphragm box (1) comprises a central protection diaphragm (4), a diaphragm box base (5) is provided on both sides of the central protection diaphragm (4), a medium isolation diaphragm (6) is provided on the diaphragm box base (5), a sealing ring (7) is sleeved on the diaphragm box base (5), and a pressure-inducing hole (24) is opened on the diaphragm box base (5), and one end of the pressure-inducing hole (24) is in contact with the central protection diaphragm (4).

10. A method for using a multi-parameter differential pressure sensor with a fully symmetrical structure and double-sided measurement, characterized in that: The following steps are involved: Filling silicone oil into two measuring chambers (23) in the base (9) through two oil filling channels (15), and sealing the two oil filling channels (15); The two pressure-inducing passages (22) are respectively connected to the pressure sources on the high-pressure side and the low-pressure side of the outside world; Obtaining two-way high-pressure side and low-pressure side pressure signals through two silicon piezoresistive chips (16); When the pressure signal output on the high-pressure side is greater than the pressure signal output on the low-pressure side, it is judged as positive pressure and the pressure signal output on the high-pressure side is taken; when the pressure signal output on the high-pressure side is less than the pressure signal output on the low-pressure side, it is judged as negative pressure and the pressure signal on the low-pressure side is taken.

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