CN113295321B - Embedded flow channel type micro-cantilever sensor and detection method - Google Patents
Embedded flow channel type micro-cantilever sensor and detection method Download PDFInfo
- Publication number
- CN113295321B CN113295321B CN202110582375.3A CN202110582375A CN113295321B CN 113295321 B CN113295321 B CN 113295321B CN 202110582375 A CN202110582375 A CN 202110582375A CN 113295321 B CN113295321 B CN 113295321B
- Authority
- CN
- China
- Prior art keywords
- cantilever beam
- pressure
- channel
- flow channel
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
Abstract
The invention provides an embedded flow channel type micro-cantilever sensor and a detection method, and relates to the field of MEMS. The difference is that the embedded slender flow channel is required to be arranged at a position close to the upper surface of the cantilever beam and far away from the neutral plane of the beam, and at the same time spans the most obvious strain area, so that the flow resistance change of the flow channel is obvious when the cantilever beam is deformed. Meanwhile, the fluid with constant volume flow rate in the micro-channel passes through, and when the deformation of the cantilever beam occurs, the pressure difference between the upstream and the downstream of the channel is measured through the pressure sensor, so that the load born by the cantilever beam can be calculated. According to the invention, the deformation of the cantilever beam is firstly converted into the flow resistance deformation quantity through the embedded flow channel, so that a variable pressure difference is formed between the upstream and downstream of the fluid, and finally the pressure sensor is converted into the electric quantity, so that the inherent defect of the traditional cantilever beam detection method when the sensor sensitive structure is arranged on the surface of the cantilever beam is avoided, and the stability and the reliability of the micro-cantilever beam sensor are improved.
Description
Technical Field
The invention mainly relates to the field of micro-electromechanical systems, in particular to a cantilever beam sensor embedded with a micro-channel and a detection method.
Background
Microelectromechanical systems are increasingly used in production and life because of their advantages such as miniaturization and integration, and many kinds of microsensors with good performance and high reliability are derived. Cantilever structures, as the simplest microstructures, can detect very small displacements or mass changes, which makes micro-cantilevers a common choice for high-precision and high-sensitivity sensors.
The object to be measured and the micro-cantilever are fixed together in a certain way, so that the micro-cantilever can be bent or resonant frequency is changed, and then the change of the micro-cantilever is read out by an optical or electrical method, and a beam deflection method, a piezoresistance method, a piezoelectric method, a capacitance method and the like are common.
In patent CN109696185a biomimetic micro-cantilever structure is disclosed, on which piezoresistors are arranged and a wheatstone bridge is formed by electrode leads. Based on the special structure stress amplification mechanism of the scorpion tarsal joint, a cantilever beam structure for hypersensitive sensing micro information is designed, but the inherent defects of additional cantilever beam bending and resistance value change caused by current generated in the signal reading process of the piezoresistive method are not compensated, and the piezoresistive method cannot be applied to a liquid environment. A lever type cantilever Liang Liusu detecting device is disclosed in patent CN112326993 a. Based on the traditional electric and mechanical principles, the invention changes the stress distribution in the cantilever beam by driving the lever to rotate through fluid so as to change the resonance frequency of the cantilever beam, and has the characteristic of high flow velocity detection sensitivity. However, the design also has a significant disadvantage that the piezoelectric method cannot be independently used for static detection, vibration needs to be applied to the cantilever beam through a vibration source when static quantities such as mass are detected, and other problems are easily caused by an additional structure. Patent CN110307919a discloses a high-sensitivity wide-range capacitive force sensor and a preparation method thereof, which adopts two different force sensitive quantities and uses the size of a plurality of variable-spacing capacitive reactions, although the measuring range of the sensor is increased, the problem of non-linearity of the capacitive sensor is not solved, and electromagnetic interference shielding of the structure is difficult to implement. In patent CN 108801468A, a micro-cantilever array optical readout imaging system and method are disclosed, and an optical readout lens group is replaced by a small hole array to realize optical readout, so that the system volume is reduced, the cost is reduced, the installation and debugging are simple, but the optical deflection method is greatly affected by the surrounding environment, the noise of a signal processing circuit is one of important factors affecting the measurement accuracy, and the optical equipment is often quite large in volume.
Disclosure of Invention
In order to overcome the defects in the prior art, a novel cantilever beam detection method is provided, and an embedded runner type micro-cantilever beam sensor is invented, which comprises a micro-cantilever beam (110), a fluid inlet (100), a fluid outlet (102) and an embedded slender runner (101); the elongated flow channel has a constant volumetric flow rate and fluid flowing in laminar flow.
Optionally, the embedded elongated runner (101) needs to be close to the upper surface of the cantilever beam and far away from the neutral surface of the cantilever beam; the embedded slender runner (101) also spans the junction of the cantilever beam fixed end and the movable end.
Optionally, the embedded flow channel (101) passes through a section of columnar cavity (131) near the fluid outlet (100) and the fluid outlet (102) respectively.
Optionally, a thin layer (132) above the columnar cavity (131) is used as a pressure sensing film, and pressure sensors (200) are respectively formed and used for detecting the fluid pressure upstream and downstream of the flow channel.
Optionally, the pressure sensor (200) is a capacitive pressure sensor.
The detection technical scheme of the invention is as follows: the variation of the cantilever Liang Fuzai is converted into the variation of the upstream and downstream pressure difference of the flow passage through the flow resistance variation of the embedded slender flow passage (101) caused by the deformation of the cantilever beam (110), and then the pressure difference variation is detected by the pressure sensor (200). Wherein when a concentrated load F is applied to the tail end of the embedded channel type cantilever beam sensor, the pressure difference between the upstream and the downstream of the micro flow channel is that
Wherein Q is v The flow rate is a constant value, C is a friction coefficient, mu is hydrodynamic viscosity, y is the distance between the core of the micro-channel and the neutral plane, L is the length of the cantilever beam, L is the length of the channel, A is the cross-sectional area of the micro-channel, D H The hydraulic diameter of the flow channel is E is the elastic modulus of the cantilever beam, I Z The moment of inertia of the cross section of the cantilever beam relative to the z axis is that N is the number of deformation sections of the micro-channel and is an even number.
Compared with the traditional piezoresistive micro-cantilever beam, the pressure-sensitive resistor has a certain similarity, the piezoresistor originally arranged at the deformation part of the cantilever beam is replaced by the embedded slender flow channel, the current is replaced by the fluid with constant volume flow rate in the flow channel, and the voltage to be detected is changed into the pressure difference between the upstream and the downstream of the micro-flow channel through the pressure sensor. Compared with the traditional electrical detection method, the method avoids adding additional structures on the surface of the cantilever beam, such as doping to obtain resistance or depositing piezoelectric materials; on the contrary, the runner serving as a sensitive structure is arranged inside the cantilever beam, so that the sensor is prevented from falling off easily like a piezoelectric material, the stability and the service life of the sensor are further improved, and the interference of an external environment can be greatly avoided. In addition, the temperature stability of the liquid is higher than that of the semiconductor material, heat is not generated during operation, and even if the pressure sensor part adopts a piezoresistive pressure sensor, extra heat generated during operation can be taken away by the fluid, and the fluid also plays a role in stabilizing the temperature of the sensor.
Therefore, the invention not only has better linearity when the sensor is stressed, but also can increase the sensitivity of the sensor by increasing the length of the flow channel and further increasing the flow resistance, and in addition, the invention also effectively avoids the defect that the piezoresistive method is greatly influenced by temperature and the defect that the piezoresistive method cannot be applied to a liquid environment. Compared with other common detection methods, the stability and the anti-interference capability of the structure are improved.
Drawings
FIG. 1 is a diagram of the structure of the cantilever beam with embedded flow channels, and FIG. 1 (a) is a top view of the structure; FIG. 1 (b) is a cross-sectional view of section A-A;
FIG. 2 is a schematic diagram of the detection principle;
FIG. 3 is a schematic diagram of a variable pole pitch capacitive pressure sensor used in the embodiments;
FIG. 4 is a functional block diagram of an integrated sensor detection system in an embodiment;
FIG. 5 is a general flowchart of the detection system software in an embodiment.
Detailed Description
The working principle and the detection method of the invention are described below by corresponding calculation formulas in combination with the accompanying drawings.
An embedded runner micro-cantilever sensor, as shown in FIG. 1, comprises a micro-cantilever (110), a fluid inlet (100), a fluid outlet (102), and an embedded elongated runner (101); the slender flow channel is internally provided with a fluid with constant volume flow rate and laminar flow movement; the embedded slender runner (101) needs to be close to the upper surface of the cantilever beam and far away from the neutral surface of the cantilever beam, and simultaneously spans the junction of the fixed end and the movable end of the cantilever beam; the micro-channels near the fluid inlet (100) and the fluid outlet (102) at the fixed end of the cantilever beam respectively pass through a section of columnar cavity (131), and a thin layer (132) at the upper side of the cavity is used as a pressure sensing film for manufacturing a pressure sensor so as to respectively detect the hydraulic pressure of fluid flowing out from the upstream and the downstream; the pressure sensor is a pole-pitch-variable capacitive pressure sensor, structurally comprises a sensitive layer which is integrated at a fixed end of a cantilever beam and is used as a movable polar plate, a columnar pressure cavity which is communicated with a flow channel is arranged in the fixed end, a lower electrode (133) which is positioned at a pressure sensing film position on the upper surface of the cantilever beam and is used as a substrate (135) of the fixed polar plate of the capacitive sensor, and an upper electrode (134) which is fixed on the substrate.
The method comprises the following steps:
step 1, converting the variation of the cantilever Liang Fuzai into the variation of the upstream and downstream pressure difference of the flow channel through the flow resistance variation of the slender flow channel (101) caused by the deformation of the cantilever beam (110), and calculating the pressure difference generated by the fluid inlet (100) and the fluid outlet (102) as
Wherein->
Wherein Q is v Is the volumetric flow rate of the fluid, C is the friction coefficient, mu is the hydrodynamic viscosity, L is the length of the flow channel, A is the cross-sectional area of the micro flow channel, D H Is the hydraulic diameter of the runner; the volume flow rate Qv of the elongated flow channel (101) is obtained according to poiseuille law;
step 2, neglecting the change of the cross section area during the bending of the cantilever beam, and obtaining the change quantity of the flow resistance of the slender flow channel (101) during deformation
DeltaL is the channel length variation of the elongated flow channel (101);
step 3, calculating the relation between the channel length variation delta L of the slender runner (101) and the initial length L;
step 4, only analyzing the deformation condition of the cantilever beam when the tail end is only subjected to concentrated load to illustrate the principle, and calculating the bending moment on the beam at the moment to be M=F (l-x); x is the distance from the infinitesimal to the fixed end of the cantilever beam, F is the concentrated load applied to the tail end of the cantilever beam, and l is the length of the cantilever beam;
step 5, obtaining the relation between the channel length variation delta L of the slender runner (101) and the concentrated load value F and the relation between the flow resistance R and the concentrated load value F by the quantities obtained in the step 2-4, considering that the stresses of the beams are not equal everywhere, further obtaining the linear relation between the flow resistance variation delta R and the concentrated load value F, and increasing the flow resistance variation when the channel length L (L < L) is increased, namely increasing the sensitivity of the sensor; as L decreases, the sensitivity factor Δr/R increases;
step 6, detecting the pressure of the fluid by adopting a capacitive pressure sensor, wherein the thin layer (132) of the columnar cavity (131) close to the upper surface side is directly used as a pressure sensing film to serve as a sensitive structure, and an electrode (133) is arranged on the thin layer; the fixed polar plate needs to be additionally provided with a substrate (135) at the fixed end of the cantilever beam, and another electrode (134) is placed on the fixed end; when the pressure exists in the fluid, the hydraulic pressure generated on the lower side of the thin layer (132) can cause the pressure sensing film to generate remarkable deformation, so that the polar distance between the pressure sensing film and the upper electrode (134) is changed, and the change of the capacitance of the miniature capacitive pressure sensor (200) is further changed;
step 7, the calculated pressure P is the resultant force acted on the pressure sensing film by the hydraulic pressure and the pressure of the dielectric layer position on the pressure sensing film, and the pressure difference delta P is equal to the pressure value measured by the pressure sensor only when the pressures of the dielectric layer positions of the two capacitance sensors are equal; the dielectric layer is connected to the outside by providing an air outlet on one side of the substrate (135) so that the pressure of the two capacitive sensors at that location is always equal to the atmospheric pressure, and the stationary plate can also draw the electrodes out here for connecting wires.
The following describes in detail the implementation of the process according to the invention:
the invention uses the embedded channel as a sensitive structure to detect the deformation of the sensor, and the principle is described by combining the slender flow channel shown in figure 2. The flow channel in fig. 2 (a) is fixedly restrained at the left and right sides, and has a section of elongated flow channel in the middle, when a certain flow rate of fluid flows through the long straight channel, a pressure difference is generated between the upstream and downstream of the long straight channel, and the value can be calculated by the following formula:
wherein ΔP is the pressure difference between the upstream pressure P1 and the downstream pressure P2, Q v Is the volumetric flow rate of the fluid, C is the friction coefficient, mu is the hydrodynamic viscosity, L is the length of the flow channel, A is the cross-sectional area of the micro flow channel, D H Is the hydraulic diameter of the flow channel. It is clear from equation (1) that a large pressure differential is created between the upstream and downstream of the elongate flow passage.
If an external force is applied to the position of the elongated flow channel at this time, the flow channel is deformed to a certain extent as shown in fig. 2 (b), and if the volumetric flow rate Qv is maintained at this time, the pressure difference Δp increases because the length L of the intermediate elongated flow channel (101) increases and the cross-sectional area a decreases.
According to poiseuille's law:
Q v ＝ΔP/R (2)
wherein R is flow resistance, and the unit is Pa.s.m -3 It can be seen from the combination of formula (1) that for the elongated flow channel in the figure, the flow resistance is calculated as:
it can be understood that the flow channel deformation results in an increase in flow resistance and thus in an increase in the pressure difference upstream and downstream of the fluid. The invention is applicable to various stress and strain detection as well as piezoresistance method, and because the flow resistance is inversely proportional to the fourth power of the cross section area of the flow passage, the effect of the structure in MEMS is far better than that in macroscopic environment.
In this embodiment, because the neutral plane is not stressed nor deformed when the cantilever beam is deformed, the embedded microfluidic (101) channel needs to be away from the neutral plane, as close to the surface as possible, and should be placed where the deformation is most pronounced.
For a section of the elongated flow channel in fig. 1, ignoring the change in cross-sectional area when the cantilever beam is bent, the amount of change in flow resistance when deformed is:
wherein the channel length variation of the elongated flow channel (101) is related to the initial length as follows:
ΔL＝εL (5)
epsilon is the positive strain of the section beam, the interface of the embedded runner is assumed to be small, the influence of the runner and fluid on the quantitative mechanical parameters is ignored, and the following steps are defined according to the stress:
wherein sigma is the positive strain of the section of beam, y is the distance from the neutral plane of the strain position, M is the bending moment born by the beam, I Z Is the moment of inertia of the beam to the z-axis.
In this embodiment, only the deformation condition of the cantilever beam when the end receives the concentrated load is analyzed to illustrate the principle, and then the bending moment on the beam is:
M＝F(l-x) (7)
x is the distance from the infinitesimal to the fixed end of the cantilever beam, F is the concentrated load applied to the tail end of the cantilever beam, and l is the length of the cantilever beam.
According to equations 4 to 7, considering that the stresses of the beams are not equal everywhere, the relation of the total deformation amount (length variation amount) and the concentrated load value is:
therefore, the relation of the flow resistance and the concentrated load F is:
as can be seen from equation 9, the flow resistance variation is in a linear relationship with the concentrated load value; and as the channel length L (L < L) increases, the amount of flow resistance change increases, i.e., the sensor sensitivity increases; as L decreases, the sensitivity factor Δr/R increases; the same and in line with the usual principles as the piezoresistive sensor. In the formula 9, only the flow resistance variation of a single-section flow channel is calculated, and since the fluid has an inlet and an outlet in practice, at least two sections of micro-channels are needed to form a section of U-shaped micro-channel, and in practice, the flow channel is designed into a serpentine shape to increase the output.
In an embodiment a capacitive pressure sensor as shown in fig. 3 is used to detect the pressure of the fluid. The cylindrical pressure sensing cavity (i.e., cylindrical cavity (131)) of the capacitive pressure sensor may be fabricated with the same process as the elongated flow channel (101). Because the embedded channel is integrally close to the upper surface, a thin layer (132) of the pressure sensing cavity (131) close to the upper surface side can be directly used as a pressure sensing film to serve as a sensitive structure, and an electrode (133) is arranged on the pressure sensing film; the fixed plate requires an additional substrate (135) at the fixed end of the cantilever beam and another electrode (134) at the upper side. When pressure exists in the fluid, the hydraulic pressure generated on the lower side of the pressure sensing film (namely the thin layer (132)) can cause the pressure sensing film to generate remarkable deformation, so that the polar distance between the pressure sensing film and the upper electrode (134) is changed, and the change of the capacitance of the miniature capacitance type pressure sensor (200) is changed.
In this embodiment, a pole pitch-variable capacitive sensor with a circular pole plate is adopted, and the capacitance value is calculated as follows:
epsilon in 0 For vacuum dielectric constant, ε r Dielectric constant, delta, of air relative to vacuum 0 The initial polar distance of the capacitor polar plate is a polar plate radius, D is bending rigidity of the pressure sensing film material, and P is pressure applied on the pressure sensing film.
The pressure P calculated by the formula (10) is a resultant force acting on the pressure sensitive film by the hydraulic pressure and the pressure of the dielectric layer position on the pressure sensitive film, and the difference between the pressure values measured by the pressure sensors is equal to the differential pressure Δp only when the pressures of the two capacitance sensor dielectric layer positions are equal. In this embodiment, the dielectric layer is connected to the outside by providing an air outlet on one side of the substrate (135), so that the pressure of the two capacitive sensors at this position is always equal to the atmospheric pressure, and the fixed electrode plate can also draw out the electrode here to connect the lead.
The capacitance value may be detected by a dedicated weak capacitance signal detection chip such as AD7746 or PCap 01. The capacitance value of the micro-capacitor is approximately tens of pF, and a PCap01 capacitor digital conversion chip is recommended to be selected, wherein the chip can measure 4 capacitors simultaneously in a drifting mode, and when the basic capacitance is 10pF, the measurement speed of 5Hz can be kept to be measured at the resolution of 6aF, so that the design requirement is met. The PCap01 and the MEMS sensor are arranged on the same packaging substrate, and the sensor is connected with a detection circuit through a wire bonding mode.
The PCap01 chip has a 48-bit signal processing unit therein, which gives the obtained measurement data to the chip output port, and outputs the data through Serial Peripheral Interface (SPI) serial communication. The PCap01 is to record the charge and discharge time of the capacitor to be measured and the time required by the reference capacitor to pass through the charge and discharge of the same resistor to calculate the capacitance value, and the output is an unsigned fixed point number with 3-bit integer 21-bit decimal, and the capacitance value to be measured can be calculated through the following formula:
c in the formula MEMS Is the capacitance to be measured, C DRO Is the ratio of the numbers read, C REF Is the value of the reference capacitance.
The PCap01 output needs to be read through a singlechip and is subjected to preliminary processing to be sent to an upper computer for further processing, recording and displaying, and an STM32 singlechip can be selected as a main control chip to control the PCap01, so that the whole circuit is built and is simple, and the whole block diagram of the measurement and control circuit system is shown in figure 4.
STM32 sends the data to the upper computer LabVIEW for processing, and the singlechip is connected with the upper computer through a serial port and adopts a Universal Asynchronous Receiver Transmitter (UART). LabVIEW realizes serial port function mainly through VISA, the program flow chart is shown in FIG. 5, the serial port is initialized according to parameters in the program of the singlechip, and the character string read into the buffer area is converted into byte arrayThe frame head can be searched by searching one-dimensional array, the data of each channel in the shift array are sequentially recombined according to the found index and are combined into a character string, the capacitance ratio is extracted by utilizing the text attribute node of the character string, and the capacitance value C is calculated according to a formula (11) m . The hydraulic pressure P at the position corresponding to the capacitance can be calculated according to the formula (10), the flow resistance R of the embedded flow channel and the variation DeltaR of the flow resistance relative to the initial value can be calculated according to the formula (2), and finally the load F applied to the tail end of the cantilever beam can be calculated according to the formula (9).
In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
Claims (3)
1. The method for detecting deformation of the embedded runner type micro-cantilever sensor is characterized in that the sensor comprises a cantilever (110), a fluid inlet (100), a fluid outlet (102) and an embedded slender runner (101); the embedded slender flow channel is internally provided with a fluid flow with constant volume flow rate and laminar flow movement; the embedded slender runner (101) passes through a section of columnar cavity (131) near the fluid inlet (100) and the fluid outlet (102) respectively;
the embedded slender runner (101) needs to be close to the upper surface of the cantilever beam and far away from the neutral surface of the cantilever beam; the embedded slender runner (101) also spans the junction of the cantilever beam fixed end and the movable end;
the detection method specifically comprises the following steps:
the change of the cantilever Liang Fuzai is converted into the change of the upstream pressure difference and the downstream pressure difference of the flow channel through the flow resistance change of the embedded slender flow channel (101) caused by the deformation of the cantilever beam (110), and then the pressure sensor (200) detects the pressure difference change; wherein when a concentrated load F is applied to the tail end of the embedded channel type cantilever beam sensor, the pressure difference between the upstream and the downstream of the micro flow channel is that
Wherein Q is v The flow rate is a constant value, C is a friction coefficient, mu is hydrodynamic viscosity, y is the distance between the core of the micro-channel and the neutral plane, L is the length of the cantilever beam, L is the length of the channel, A is the cross-sectional area of the micro-channel, D H The hydraulic diameter of the flow channel is E is the elastic modulus of the cantilever beam, I Z The moment of inertia of the cross section of the cantilever beam to the z axis is that N is the number of deformation sections of the micro-channel and is an even number;
the detection method comprises the following steps:
step 1, converting the variation of the cantilever Liang Fuzai into the variation of the upstream and downstream pressure difference of the flow channel through the flow resistance variation of the slender flow channel (101) caused by the deformation of the cantilever beam (110), and calculating the pressure difference generated by the fluid inlet (100) and the fluid outlet (102) as
Wherein->
Wherein Q is v Is the volumetric flow rate of the fluid, C is the friction coefficient, mu is the hydrodynamic viscosity, L is the length of the flow channel, A is the cross-sectional area of the micro flow channel, D H Is the hydraulic diameter of the runner; the volume flow rate Qv of the elongated flow channel (101) is obtained according to poiseuille law;
step 2, neglecting the change of the cross section area during bending of the cantilever beam, and solving the slender shape during deformationVariation of flow resistance of the flow channel (101)
DeltaL is the channel length variation of the elongated flow channel (101);
step 3, calculating the relation between the channel length variation delta L of the slender runner (101) and the initial length L;
step 4, only analyzing the deformation condition of the cantilever beam when the tail end is only subjected to concentrated load to illustrate the principle, and calculating the bending moment on the beam at the moment to be M=F (l-x); x is the distance from the infinitesimal to the fixed end of the cantilever beam, F is the concentrated load applied to the tail end of the cantilever beam, and l is the length of the cantilever beam;
step 5, obtaining the relation between the channel length variation delta L of the slender runner (101) and the concentrated load value F and the relation between the flow resistance R and the concentrated load value F by the quantities obtained in the step 2-4, considering that the stresses of the beams are not equal everywhere, further obtaining the linear relation between the flow resistance variation delta R and the concentrated load value F, and increasing the flow resistance variation when the channel length L (L < L) is increased, namely increasing the sensitivity of the sensor; as L decreases, the sensitivity factor Δr/R increases;
step 6, detecting the pressure of the fluid by adopting a capacitive pressure sensor, wherein the thin layer (132) of the columnar cavity (131) close to the upper surface side is directly used as a pressure sensing film to serve as a sensitive structure, and an electrode (133) is arranged on the thin layer; the fixed polar plate needs to be additionally provided with a substrate (135) at the fixed end of the cantilever beam, and another electrode (134) is placed on the fixed end; when the pressure exists in the fluid, the hydraulic pressure generated on the lower side of the thin layer (132) can cause the pressure sensing film to generate remarkable deformation, so that the polar distance between the pressure sensing film and the upper electrode (134) is changed, and the change of the capacitance of the miniature capacitive pressure sensor (200) is further changed;
step 7, the calculated pressure P is the resultant force acted on the pressure sensing film by the hydraulic pressure and the pressure of the dielectric layer position on the pressure sensing film, and the pressure difference delta P is equal to the pressure value measured by the pressure sensor only when the pressures of the dielectric layer positions of the two capacitance sensors are equal; the dielectric layer is connected to the outside by providing an air vent on one side of the substrate (135) so that the pressure of the two capacitive sensors at that location is always equal to the atmospheric pressure, while the stationary plate also draws the electrodes there to connect the leads.
2. The method according to claim 1, wherein the thin layers (132) above the columnar cavities (131) are used as pressure sensing films, respectively forming pressure sensors (200) for detecting the fluid pressures upstream and downstream of the flow channels.
3. The method according to claim 2, wherein the pressure sensor (200) is a capacitive pressure sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110582375.3A CN113295321B (en) | 2021-05-26 | 2021-05-26 | Embedded flow channel type micro-cantilever sensor and detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110582375.3A CN113295321B (en) | 2021-05-26 | 2021-05-26 | Embedded flow channel type micro-cantilever sensor and detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113295321A CN113295321A (en) | 2021-08-24 |
| CN113295321B true CN113295321B (en) | 2023-05-09 |
Family
ID=77325430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110582375.3A Active CN113295321B (en) | 2021-05-26 | 2021-05-26 | Embedded flow channel type micro-cantilever sensor and detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113295321B (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1323287C (en) * | 2004-11-10 | 2007-06-27 | 中国科学院长春光学精密机械与物理研究所 | Flexible plate wave differential pressure type micro flow transducer and fabricating method thereof |
| JP2009069006A (en) * | 2007-09-13 | 2009-04-02 | Fujifilm Corp | Cantilever sensor, material detecting system using the same, and material testing system |
| CN102564681A (en) * | 2012-02-17 | 2012-07-11 | 浙江大学 | Method for determining flowing state of medium in pipeline for ultrasonic gas meter |
| CN103234961A (en) * | 2013-04-16 | 2013-08-07 | 中国电子科技集团公司第三十八研究所 | Micro-cantilever beam array biochemical sensing apparatus and biochemical detection method thereof |
| CN109879238A (en) * | 2019-01-15 | 2019-06-14 | 江苏大学 | Micro-cantilever device, processing method and a kind of detection method of embedded channel-type |
| CN109896498A (en) * | 2019-01-15 | 2019-06-18 | 江苏大学 | A kind of parallel-connection structure and processing method of embedded channel micro-cantilever |
| CN110132479B (en) * | 2019-05-06 | 2020-10-30 | 中国科学院理化技术研究所 | Microsensor for measuring microfluidic pressure |
| CN111442875B (en) * | 2020-03-13 | 2021-03-19 | 北京航空航天大学 | Underwater differential pressure sensor and preparation method thereof |
-
2021
- 2021-05-26 CN CN202110582375.3A patent/CN113295321B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113295321A (en) | 2021-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7503221B2 (en) | Dual span absolute pressure sense die | |
| Sheplak et al. | MEMS shear stress sensors: promise and progress | |
| CN103941041B (en) | A kind of single mass three-shaft mems accelerometer of three-frame structure | |
| Harada et al. | Various applications of resonant pressure sensor chip based on 3-D micromachining | |
| US10393608B2 (en) | Pressure change measuring apparatus and pressure change measuring method | |
| CN102116692A (en) | Fiber bragg grating pressure sensor and corresponding measuring method thereof | |
| KR20140065363A (en) | A measuring device for measuring a physical quantity | |
| EP3258235A1 (en) | Differential pressure transducer | |
| US20070028683A1 (en) | Apparatus and method for sensing pressure utilizing a deformable cavity | |
| Devi et al. | A squared bossed diaphragm piezoresistive pressure sensor based on CNTs for low pressure range with enhanced sensitivity | |
| CN110220636B (en) | Capillary communicating pipe type differential pressure sensor and measuring method | |
| Pan et al. | Characterization of microfabricated shear stress sensors | |
| CN113295321B (en) | Embedded flow channel type micro-cantilever sensor and detection method | |
| CN101493367A (en) | Miniature dynamical stress sensor based on MEMS technology and method of producing same | |
| CN114216648B (en) | High-frequency-response wide-range MEMS friction resistance sensor | |
| Han et al. | Miniature capacitance diaphragm gauge for absolute vacuum measurement | |
| Nie et al. | A theoretical model and analysis of composite membrane of a piezoresistive pressure sensor | |
| Wang et al. | Silicon monolithic microflow sensors: A review | |
| Paliwal et al. | Design and simulation of digital output MEMS pressure sensor | |
| Beeby et al. | Design and fabrication of a low-cost microengineered silicon pressure sensor with linearised output | |
| Jindal et al. | Novel MEMS piezoresistive sensor with hair-pin structure to enhance tensile and compressive sensitivity and correct non-linearity | |
| Ghanbari et al. | Investigating Static and Dynamic Behavior of the Strain Gauge Type Pressure Sensor in Exposure to Thermal Stresses | |
| CN112285384A (en) | Acceleration sensor based on mechanical metamaterial structure | |
| Ferrari et al. | Printed thick-film capacitive sensors | |
| Han et al. | A high accuracy resonant pressure sensor with lateral driven and piezoresistive detection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |