CN116499633A - High-precision ultralow-pressure sensor - Google Patents
High-precision ultralow-pressure sensor Download PDFInfo
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- CN116499633A CN116499633A CN202310350168.4A CN202310350168A CN116499633A CN 116499633 A CN116499633 A CN 116499633A CN 202310350168 A CN202310350168 A CN 202310350168A CN 116499633 A CN116499633 A CN 116499633A
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- 239000012530 fluid Substances 0.000 claims abstract description 15
- 238000007789 sealing Methods 0.000 claims abstract description 14
- 238000004806 packaging method and process Methods 0.000 claims abstract description 10
- 239000004973 liquid crystal related substance Substances 0.000 claims description 12
- 238000013461 design Methods 0.000 claims description 8
- 239000003292 glue Substances 0.000 claims description 2
- 238000005476 soldering Methods 0.000 claims 1
- 230000010354 integration Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000012827 research and development Methods 0.000 description 2
- 230000029058 respiratory gaseous exchange Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000012536 packaging technology Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/14—Housings
- G01L19/141—Monolithic housings, e.g. molded or one-piece housings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/14—Housings
- G01L19/148—Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention provides a high-precision ultra-low pressure sensor, which comprises a pressure sensor core chip, an application specific integrated circuit, a circuit board and a packaging structure. The pressure sensor core chip and the special integrated circuit are integrated on the same circuit board; the packaging structure comprises a shell, a baffle and a sealing ring. The upper end of the shell is provided with two air nozzles. The circuit board, the baffle and the shell form a cavity A and a cavity B, the two air nozzles are respectively communicated with the two cavities, the pressure sensor core chip is arranged in the cavity A, and the special integrated circuit is arranged in the cavity B. The sealing ring ensures the tightness of the cavity; the pressure guide holes are distributed on the baffle plate, and the two sealing cavities are communicated, so that the flow speed of fluid is not affected, and meanwhile, pressure difference can be generated, a pressure sensitive signal is provided for the pressure sensor, and the resolution of the sensor is improved; the circuit board is internally provided with a long through hole, so that the stable operation of the fluid flow is ensured. Compared with the existing ultra-low pressure sensor, the ultra-low pressure sensor has the advantages of low power consumption, low cost, high precision and easy integration.
Description
Technical Field
The invention belongs to the technical field of microelectronic sensors, and relates to a high-precision ultralow-pressure sensor.
Background
The pressure sensor is a device capable of sensing a pressure signal and converting the pressure signal into an electrical signal, and is generally composed of a pressure sensitive element and a signal processing unit. The pressure sensor is one of products with the largest share ratio in the sensor market, is widely applied in the industrial field, and relates to various industries such as electric power, medical treatment, electronics, household appliances, automobiles, railways, ships, mechanical equipment, oil gas, chemical industry, pipelines, aerospace, military industry and the like. The pressure sensors can be classified into low pressure, medium pressure and high pressure sensors according to the measuring range. MEMS pressure sensors are low pressure sensors, and the main detection principles are silicon capacitive and silicon piezoresistive, where the lowest full scale of 0.07psi (500 Pa) is listed as the ultra-low pressure measurement range.
With the continuous appearance of novel semiconductor materials, the processing technology of MEMS, the structural design of the sensor and the integrated design of the sensitive element are also continuously broken through, and the characteristics of low cost, high accuracy, mass production, small volume and the like lead the application range of the MEMS pressure sensor to be wider and wider. Many applications now require a wide variety of designs that can provide extremely high accuracy ultra-low pressure sensors, including medical ventilators and Variable Air Volume (VAV) control systems for building energy conservation. The existing ultra-low pressure sensor is mainly based on two working principles, one is based on a thermal type principle, and differential pressure is measured through a thermal type sensor element based on a flow-through principle; another is the MEMS piezoresistive principle, where the sensor is fully calibrated and temperature compensated by an Application Specific Integrated Circuit (ASIC), ensuring the sensor's test accuracy. However, the ultra-low pressure sensor technologies of the two different working principles are fully mature abroad and are widely applied to the field of respirators, the ultra-low pressure sensor products are mainly concentrated in the range of 500 Pa-1 MPa, and the ultra-low pressure sensor with the pressure lower than 500Pa cannot meet the requirements of users due to the reasons of preparation or packaging technology and the like, so that the ultra-low pressure sensor has few reports on the sensors in the range.
In summary, with the development of the internet of things, the intelligent product gradually approaches to the miniaturization direction, so that the requirements on the accuracy of measurement of medium and low pressure are improved, and meanwhile, the market has higher requirements on the convenience, cost performance and application range of the product. The ultra-low pressure sensor is focused more and more because of the advantages of small range, high precision and the like, the ultra-low pressure sensor mounted in the breathing machine on the market at present is completely dependent on foreign import, is limited by core technology, and has no autonomous research and development technology for preparing the ultra-low pressure sensor in China. The huge population base in China objectively determines that the breathing machine has huge market development space, so that the autonomous research and development of the ultra-low pressure sensor can further make up the application requirements of equipment required in the related domestic fields.
Disclosure of Invention
The invention aims to provide a high-precision ultralow pressure sensor, which adopts an MEMS pressure sensor to sense the pressure in a front flow channel and a rear flow channel to realize the accurate measurement of a small-range pressure difference and has the characteristics of small pressure loss, low cost and high precision.
The technical solution of the invention is as follows: a high-precision ultra-low pressure sensor comprises a pressure sensor core chip, an Application Specific Integrated Circuit (ASIC), a circuit board and a packaging structure. The pressure sensor core chip and an Application Specific Integrated Circuit (ASIC) are integrated on the same circuit board; the packaging structure consists of a shell, a baffle and a sealing ring. The shell upper end is provided with two air nozzles for connecting outside pipeline, baffle and shell structure as an organic whole. The circuit board and the baffle are assembled with the shell to form two cavities (cavity A and cavity B), the two air nozzles are respectively communicated with the two cavities, the pressure sensor core chip is arranged in the cavity A, and the Application Specific Integrated Circuit (ASIC) is arranged in the cavity B. The sealing ring ensures the tightness of the cavity; the pressure guide holes are distributed on the baffle plate, and the two sealing cavities are communicated, so that the flow speed of fluid is not affected, and meanwhile, the pressure difference can be generated, and a pressure sensitive signal is provided for the pressure sensor; a long through hole is formed in the circuit board, one side of the long through hole is communicated with the cavity B, the other side of the long through hole is communicated with the bottom of the pressure sensor core chip sensitive film, and the pressure sensor core chip sensitive film senses pressure difference changes in the cavity A and the cavity B. Four paths of contact pins are welded on the circuit board and used for transmitting sensor signals.
According to the circuit board, the long through hole of the circuit board is designed, the pressure sensor is integrated on the circuit board, the pressure difference between the front end and the rear end is sensed through the sensitive film, one side of the sensitive film is communicated with the cavity A, the other side of the sensitive film is communicated with the cavity B, and the circuit board is arranged on one side of the sensitive film, so that the pressure sensor is communicated to the cavity B in a mode of arranging the long through hole on the circuit board. The design of the size of the long through hole is to comprehensively consider three factors of the thickness of the circuit board, the length of the circuit board and the diameter of the sensitive film. The shell is provided with the grooves around the inner cavity, and the sealing rings and the grooves are in seamless connection to ensure the tightness of the cavity. The sealing ring is tightly connected with the circuit board through glue.
The pressure sensor core chip and an Application Specific Integrated Circuit (ASIC) are connected with the circuit board in a welding mode. According to the pressure guide hole, the structural design is combined with the fluid flow velocity according to the requirement of the ultra-low pressure measurement range, and the structural parameters of the pressure guide hole are calculated through a formula (1).
（1）
（2）
Wherein, the liquid crystal display device comprises a liquid crystal display device,for the fluid flow rate,in order for the coefficient of flow to be out,in order to be a coefficient of expansion,in order to form the aperture of the pressure guide hole,is the diameter of the cavity body, and the diameter of the cavity body is equal to the diameter of the cavity body,is the equivalent diameter ratio of the two-dimensional spherical lens,in the event of a pressure differential across the substrate,in order to achieve a fluid density,the number of the pressure guide holes is the number.
The cavity diameter described in formula (2) is to the condition that the cavity is the pipe, for the invention patent of this application, the pressure guiding hole distributes on the baffle, and the baffle is square structure, in order to satisfy the applicable condition, utilizes the area to occupy the ratio, converts the diameter proportional relation into area proportional relation, namely formula (2) converts formula (3).
（3）
Wherein, the liquid crystal display device comprises a liquid crystal display device,is the baffle area. The pressure guide holes are distributed on the baffle plate, and the specific layout and the structure size can be adjusted according to specific application requirements.
Compared with the prior art, the invention has the advantages that: according to the high-precision ultralow pressure sensor, the pressure difference is generated in the mode that the baffle and the pressure guide hole are additionally arranged in the sensor packaging shell, so that the sensor can be used for identifying the tiny pressure difference, the resolution of the sensor is improved, and meanwhile, the long through hole is designed in the circuit board, so that the stable operation of the fluid flow is ensured. Compared with the existing ultra-low pressure sensor, the ultra-low pressure sensor has the advantages of low power consumption, low cost, high precision and easiness in integration.
Drawings
Fig. 1 (a) is a front view of a structure of a high-precision ultra-low pressure sensor according to the present invention.
Fig. 1 (b) is a top view of a high-precision ultra-low pressure sensor structure according to the present invention.
FIG. 2 is a schematic diagram of a high-precision ultra-low pressure sensor baffle and pressure guiding hole structure according to the present invention.
Fig. 3 is a schematic diagram of a long through hole structure of a circuit board of a high-precision ultra-low voltage sensor according to the present invention.
In the figure:
the pressure sensor comprises a 1-pressure sensor core chip, a 2-Application Specific Integrated Circuit (ASIC), a 3-circuit board, a 4-packaging structure, a 5-shell, a 6-baffle, a 7-air tap, an 8-cavity A, a 9-cavity B, a 10-pressure guide hole, a 11-long through hole, a 12-sealing ring and a 13-signal interface.
Detailed Description
Fig. 1 is a schematic diagram of a high-precision ultra-low pressure sensor. Comprises four parts of a pressure sensor core chip 1, an Application Specific Integrated Circuit (ASIC) 2, a circuit board 3 and a packaging structure 4. The pressure sensor core chip 1 and an Application Specific Integrated Circuit (ASIC) 2 are integrated on the same circuit board 3; the packaging structure 4 is composed of a shell 5, a baffle 6 and a sealing ring 12. The upper end of the shell 5 is provided with two air nozzles 7 for connecting an external pipeline, the baffle 6 and the shell 5 are of an integrated structure, two cavities (a cavity A-8 and a cavity B-9) are formed after the circuit board 3, the baffle 6 and the shell 5 are assembled, the two air nozzles 7 are respectively communicated with the cavity A-8 and the cavity B-9, the pressure sensor core chip 1 is arranged in the cavity A-8, and the Application Specific Integrated Circuit (ASIC) 2 is arranged in the cavity B-9. The sealing ring 12 ensures the tightness of the cavity; the pressure guide holes 10 are distributed on the baffle 6, and are used for communicating the two sealing cavities, so that the flow speed of fluid is not affected, and meanwhile, the pressure difference can be generated, and a pressure sensitive signal is provided for the ultra-low pressure sensor; the circuit board 3 is internally provided with a long through hole 11, one side of the long through hole 11 is communicated with the cavity B-9, the other side of the long through hole is communicated with the bottom of the sensitive film of the pressure sensor core chip 1, and the sensitive film of the pressure sensor core chip 1 simultaneously senses the pressure difference change between the cavity A-8 and the cavity B-9. The circuit board 3 is soldered with four pins as a signal interface 13.
Fig. 2 is a schematic diagram of a structure of a high-precision ultra-low pressure sensor baffle and a pressure guiding hole. The pressure guide holes 10 are distributed on the baffle 6, and the air communicated with the cavity A-8 and the cavity B-9 circulates, so that the influence of the baffle on the fluid flow rate is reduced. The structural dimension design of the pressure guiding hole 10 comprises the following specific steps:
(1) Setting a pressure measuring range of a high-precision ultra-low pressure sensor;
(2) Combining the fluid flow velocity, obtaining the equivalent diameter ratio according to the formula (1)；
（1）
Wherein, the liquid crystal display device comprises a liquid crystal display device,for the fluid flow rate,in order for the coefficient of flow to be out,in order to be a coefficient of expansion,is the equivalent diameter ratio of the two-dimensional spherical lens,in the event of a pressure differential across the substrate,is the fluid density.
(3) Equivalent diameter ratioThe functional relation between the pressure guide hole structure and the pressure guide hole structure is shown in a formula (2);
（2）
wherein, the liquid crystal display device comprises a liquid crystal display device,in order to form the aperture of the pressure guide hole,is the diameter of the cavity body, and the diameter of the cavity body is equal to the diameter of the cavity body,the number of the pressure guide holes is the number. Equivalent diameter ratioIs in proportional relation with the number of the pressure guide holes, the aperture of the pressure guide holes and the diameter of the pipeline. The cavity of the invention patent is square, the calculation cannot be directly performed by adopting the formula (2), the diameter ratio is converted into the area ratio in order to meet the applicable condition, namely, the ratio of the total area of the pressure guide hole to the area of the baffle plate is replaced by adopting the ratio of the total area of the pressure guide hole to the area of the baffle plate, and the formula (2) is converted into the formula (3).
（3）
Wherein, the liquid crystal display device comprises a liquid crystal display device,is the baffle area. And (3) obtaining the optimal solution of the aperture of the pressure guide holes and the number of the pressure guide holes according to the formula (3). The specific layout and the structural size of the pressure guide holes can be adjusted according to practical application requirements.
Fig. 3 is a schematic diagram of a long through hole structure of a circuit board of a high-precision ultra-low voltage sensor. The long through hole 11 is designed so that the pressure sensor core chip 1 senses the pressure difference of the cavity a-8 and the cavity B-9 at the same time. The center of the aperture on one side of the long through hole 11 is aligned with the sensitive film of the pressure sensor core chip 1, and the other side of the long through hole is directly communicated with the cavity B-9, so that the pressure sensor core chip 1 can sense micro pressure change in real time, and the design of the aperture of the long through hole 11 needs to simultaneously consider the sensitive film structure and the circuit board thickness structure size.
Claims (6)
1. The high-precision ultra-low pressure sensor is characterized by comprising a pressure sensor core chip, an Application Specific Integrated Circuit (ASIC), a circuit board and a packaging structure; the pressure sensor core chip and an Application Specific Integrated Circuit (ASIC) are integrated on the same circuit board; the packaging structure consists of a shell, a baffle and a sealing ring; the upper end of the shell is provided with two air nozzles which are connected with an external pipeline; the circuit board, the baffle and the shell form two cavities (cavity A and cavity B) after being assembled, and the two air nozzles are respectively communicated with the two cavities; the baffle is provided with pressure guide holes which are communicated with the cavity A and the cavity B; a long through hole is formed in the circuit board; and the long through hole is communicated with the cavity B and the bottom of the pressure sensor core chip.
2. The high-precision ultra-low pressure sensor of claim 1, wherein said pressure sensor core chip is disposed within cavity a and said Application Specific Integrated Circuit (ASIC) is disposed within cavity B; the baffle and the shell are of an integrated structure.
3. The high-precision ultra-low pressure sensor according to claim 1, wherein the long through hole is communicated with the bottom of the sensitive film of the pressure sensor core chip, and the pressure in the cavity B is transmitted to the sensitive film of the pressure sensor core chip, so that the pressure sensor core chip can simultaneously sense the pressure change in the cavities A and B.
4. The high-precision ultra-low pressure sensor of claim 1, wherein four-way pins are soldered on the circuit board for transmitting sensor signals.
5. The high-precision ultra-low pressure sensor according to claim 1, wherein the pressure sensor core chip and the Application Specific Integrated Circuit (ASIC) are connected to a circuit board by soldering; the sealing ring is connected with the circuit board through glue.
6. The high-precision ultra-low pressure sensor according to claim 1, wherein the pressure guide holes are distributed on the baffle plate, and gas communicating with the cavity A and the cavity B circulates. The structural dimension design of the pressure guide hole comprises the following specific steps:
(1) Setting a pressure measuring range of a high-precision ultra-low pressure sensor;
(2) Combining the fluid flow velocity, obtaining the equivalent diameter ratio according to the formula (1)；
（1）
(3) Equivalent diameter ratioThe functional relation between the pressure guide hole structure and the pressure guide hole structure is shown in a formula (2);
（2）
(4) Converting the diameter ratio into the area ratio, namely replacing the diameter ratio of the total area of the pressure guide hole and the area of the baffle by adopting the proportional relation of the total area of the pressure guide hole and the area of the baffle, and converting the formula (2) into the formula (3);
（3）
(5) Obtaining the aperture of the pressure guide hole according to the formula (3)And the number of pressure guiding holes->The specific layout, the structural size and the number of the pressure guide holes can be adjusted according to the actual application requirements,
wherein, the liquid crystal display device comprises a liquid crystal display device,for fluid flow rate->For outflow coefficient->Is of a coefficient of expansion>Is equivalent diameter ratio>For pressure difference>For fluid density->Is the aperture of the pressure guiding hole->Is the diameter of the cavity>For the number of pressure guiding holes, the number is->Is the baffle area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310350168.4A CN116499633A (en) | 2023-04-04 | 2023-04-04 | High-precision ultralow-pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310350168.4A CN116499633A (en) | 2023-04-04 | 2023-04-04 | High-precision ultralow-pressure sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116499633A true CN116499633A (en) | 2023-07-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310350168.4A Pending CN116499633A (en) | 2023-04-04 | 2023-04-04 | High-precision ultralow-pressure sensor |
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| Country | Link |
|---|---|
| CN (1) | CN116499633A (en) |
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2023
- 2023-04-04 CN CN202310350168.4A patent/CN116499633A/en active Pending
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