WO2017200287A1

WO2017200287A1 - Condenser-type membrane sensor measurement device and method, which use mechanical resonance property of membrane

Info

Publication number: WO2017200287A1
Application number: PCT/KR2017/005101
Authority: WO
Inventors: 박주성; 박영주
Original assignee: 박주성
Priority date: 2016-05-17
Filing date: 2017-05-17
Publication date: 2017-11-23
Also published as: KR20170129354A; KR101842350B1

Abstract

The present invention relates to a condenser-type membrane sensor measurement device and method, which use a mechanical resonance property of a membrane and, to a device and a method for applying, to a membrane sensor for sensing a condenser capacity change, an alternating current signal (alternating current voltage or current) and a direct current signal near a mechanical resonance frequency of a sensing electrode so as to maximize displacement of the sensing electrode, thereby increasing the measurement precision of a condenser-type membrane sensor.

Description

Measuring Apparatus and Method for Condenser Membrane Sensor Using Mechanical Resonance Characteristics of Membrane

The present invention relates to a measuring device and method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, the AC signal (AC voltage or current) near the mechanical resonance frequency of the sensing electrode in the membrane sensor for detecting the change in capacitor capacity The present invention relates to a method and apparatus for increasing the detection accuracy of a membrane sensor by maximizing the displacement of the sensing electrode by applying a direct current voltage).

Membrane-based sensors are currently used in many industries.

In particular, attempts have been made to use membrane sensors in pressure sensors for detecting toxic gas leaks and biosensors for diagnosing diseases.

The membrane sensor may measure a minute change in mass of the sensing electrode and a pressure change applied to the sensing electrode, and thus may be used to detect whether a highly explosive gas or an extreme gas leaks.

In the medical community, efforts to label-free disease inspection using active mass change of the sensing electrode of the membrane sensor have been actively conducted to compensate for the disadvantages of the conventional disease inspection method using phosphors.

A disease can be diagnosed by applying an antigen or a substance that reacts to a specific protein on a sensing electrode and reacting a sample taken from humans or animals to observe the mass of the sensing electrode or the pressure change applied to the sensing electrode.

In general, the membrane sensor can be classified into two types using the piezoelectric effect and the change in capacitor capacity.

In the case of using the piezoelectric effect, the piezoelectric effect of changing the resistance according to the pressure applied to the sensing electrode is used. The piezoelectric material is coated on the membrane sensor sensing electrode and the pressure or mass change applied to the sensing electrode is converted into a resistance change.

As a method of measuring the resistance change due to the piezoelectric effect, a membrane sensor sensing electrode is configured by a Wheatstone bridge, and then a resistance change is measured by applying a DC voltage.

Another method is to change the AC voltage frequency applied to the membrane sensor sensing electrode and use the phenomenon that the displacement of the piezoelectric element increases when the AC voltage frequency reaches the mechanical resonance frequency of the sensing electrode. (US2015 / 0143911 A1)

On the other hand, in the condenser type membrane sensor, the first method of measuring the pressure or mass applied to the sensing electrode is to measure the displacement of the sensing electrode using a laser, and the second method is the oscillation according to the displacement of the sensing electrode. There is a way to measure the change in frequency.

In addition, the third method changes the weak AC voltage frequency applied to the condenser-type membrane sensor so that when the AC voltage frequency coincides with the mechanical resonance frequency of the membrane sensor, the voltage applied to the sensing electrode changes by 180 degrees and the voltage drops. There is a method of measuring mass change using voltage bump characteristics (US9,032,797 B2).

On the other hand, the prior art of the present invention has been filed and registered a "micro-mass measuring sensor having a sensing column" of the patent registration number "10-0798361", the fine mass measuring sensor having a sensing column is a predetermined radius (a) and A plate-shaped membrane having a thickness (h), a columnar shape having a predetermined length (H) and extending, one side of which is attached to the central portion of the membrane and the other side of the sensing column to which the measurement material is attached, and the predetermined portion of the membrane Piezoelectric material deposited in position.

In general, a capacitor is made by attaching conductor electrodes to both sides of a dielectric, and the capacity of the capacitor can be summarized by Equation 1, where

Is the dielectric constant of the dielectric, A is the area of the electrode, and d is the spacing between the electrodes.

As shown in FIG. 1, the condenser-type membrane sensor 1 has a structure in which the fixed electrode 3 is fixed to the bottom of the membrane sensor 1 and the sensing electrode 9 attached to the dielectric electrode 7 moves. .

In addition, the condenser type membrane sensor 1 may fix the dielectric electrode 7 and move the sensing electrode 9 as shown in FIG. 2.

In this case, the capacitance between the sensing electrode 9 and the fixed electrode 3 may be summarized by Equation 2 when two capacitors are connected in series.

In Equation 2

Is the capacity of the dielectric,

Is the capacity of air or vacuum

,

Can be cleaned up as

here

Is the thickness of the dielectric film,

Is the dielectric constant of the dielectric,

Is the permittivity of air,

Is the thickness of the air.

In this case, the dielectric constant of the dielectric is much larger than that of air and the thickness of the dielectric is small

The relationship between the sensing electrode 9 and the fixed electrode 3 is determined by the dielectric constant of air.

) And spacing (

Is determined by

In general, the condenser type membrane sensor 1, which measures the mass in micrograms or picograms or the pressure in mbars, detects the movement of the sensing electrode 9. Use air or vacuum to make it easier.

In the condenser type membrane sensor 1, when a material reacting with a specific material is applied to the sensing electrode 9, the specific material reacts with the sensing electrode 9 so that the mass of the sensing electrode 9 is increased or decreased. do.

At this time, when the mass of the sensing electrode 9 is increased, the sensing electrode 9 descends and the gap between the sensing electrode 9 and the fixed electrode 3 decreases, thereby increasing the capacitor capacity of the condenser type membrane sensor 1. .

In contrast, when the mass is reduced, the capacity is reduced.

In this case, by measuring the change in the capacitor capacity of the condenser-type membrane sensor 1, it is possible to measure the change in mass of the sensing electrode (9).

Applying a substance that reacts well with a specific disease sample on the sensing electrode and reacting a specimen of the person with the disease changes the mass of the sensing electrode 9 to determine whether the disease is infected.

When a material that reacts well with a special gas is applied to the sensing electrode 9, the mass of the sensing electrode 9 changes in response to the gas.

Using this concept, the condenser type membrane sensor 1 can diagnose diseases, detect toxic or special gases.

In addition, in the case of the pressure sensor using the condenser type membrane sensor 1, the pressure is measured by using the phenomenon that the capacitor capacity of the condenser type membrane sensor 1 changes as the position of the sensing electrode 9 is changed by the pressure. can do.

In a more quantitative analysis, the mechanical resonance frequency of the condenser membrane sensor 1 can be summarized by Equation 3.

In Equation 3 above '

'Is the coefficient according to the shape of the sensing electrode,' t 'is the thickness of the material attached to the sensing electrode (9),' d 'is the radius when the sensing electrode 9 is spherical and the length of one side when the square And "

'Means density of the material attached to the sensing electrode 9.

Also, '

'Is the Young's modulus of the sensing electrode 9, and' E 'is the Poisson's ratio of the electrode.

The Young's modulus is an elastic modulus representing the relationship between the deformation occurring in the object and the pressure applied to the sensing electrode 9. Therefore, when the mechanical resonance frequency of the sensing electrode 9 mounted on the condenser type membrane sensor is investigated, The pressure applied to the sensing electrode 9 can be measured.

The poisson ratio is a constant determined by the material of the sensing electrode 9.

In Equation 3, the mechanical resonance frequency is the density of the sensing electrode 9 (

It is inversely proportional to).

Since the density of the sensing electrode sensor 9 is proportional to the mass of the sensing electrode 9, the change in mass may be measured by changing the mechanical resonance frequency of the sensing electrode 9.

The quality factor (Q-factor), which is one of the important parameters of the membrane sensor 1, can be expressed as Equation (4).

In Equation 4, f ₀ is the mechanical resonance frequency of the sensing electrode 9 represented by Equation 3, m is the mass of the sensing electrode,

Is the coefficient of damping factor of the sensing electrode 9. In Equation 4, the mass of the sensing electrode 9 can be measured by using a quality factor (Q-factor) of the membrane sensor 9.

However, in general, the capacitor capacitance of the sensing electrode 9 of the membrane sensor 1 is much smaller than the other parasitic capacitances of the membrane sensor 1, so the mechanical resonance frequency and the Q-factor of the sensing electrode 9 The change cannot be easily measured.

Accordingly, the present invention provides a method and apparatus for improving the sensitivity and precision of the condenser type membrane sensor for measuring the mass or pressure by using the mechanical resonance characteristics of the sensing electrode mounted on the membrane sensor to solve the above problems. There is a purpose.

The fundamental principle of the means for achieving the above object is to apply the AC signal having a mechanical resonance frequency to the sensing electrode 9 of the membrane sensor 1 by using the principle that the sensing electrode 9 vibrates greatly, In 1), the frequency of the alternating current signal (AC voltage or current), which is necessary for measuring the change in capacitance of the sensing electrode 9, is set near the mechanical resonance frequency of the sensing electrode 9 to increase the vibration of the sensing electrode 9. will be. As the vibration increases, a change in the distance between the sensing electrode 9 and the fixed electrode 3, that is, the air gap (d2 in FIGS. 1 and 2) becomes large, resulting in a large change in the capacitor capacity of the sensing electrode 9.

When the frequency of the AC signal applied to the sensing electrode 9 is out of the mechanical resonance frequency, the capacitance change of the sensing electrode 9 is not large so that the signal from the membrane sensor 1 becomes small, but the sensing electrode 9 When the frequency of the AC signal applied to the vicinity of the mechanical resonance frequency of the sensing electrode 9, the signal output from the sensor is increased.

The present invention includes a microprocessor and an analog signal generator, while varying the frequency of an AC signal of a predetermined magnitude or more, based on the magnitude of an AC signal output from the sensing electrode 9 by being applied to the membrane sensor 1 or The Q-factor is used to measure the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9.

The measuring device for condenser type membrane sensor using the mechanical resonance characteristic of the membrane according to the present invention inputs an AC signal and a DC signal while varying the frequency and the magnitude of the condenser type membrane sensor 1, respectively. The membrane for measuring the mass change or pressure of the sensing electrode 9 by obtaining the mechanical resonance frequency or the Q-factor of the sensing electrode from the frequency spectrum of the signal output from the sensing electrode 9 corresponding to A measuring device for condenser type membrane sensor using the mechanical resonance characteristic of the sensor, wherein the mechanical resonant frequency of the sensing electrode 9 obtained from the frequency spectrum of the device is the AC signal among a plurality of frequencies resonating the sensing electrode 9. Characterized in that the mechanical resonant frequency common to the size of .

In addition, the magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 as compared with a parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1, and thus the mechanical resonance frequency. When the excitation AC signal is applied to the membrane sensor 1, it is characterized in that the signal of the mechanical resonant frequency is output the largest from the sensing electrode (9).

In addition, the frequency spectrum of the signal coming from the sensing electrode (9) while varying the frequency at a specific magnitude of the signal when the AC signal and the DC voltage, the magnitude and frequency of each of the capacitor type member sensor is input to It is characterized in that it is calculated from the average value of the signal obtained by measuring times.

The apparatus according to the present invention is characterized in that the AC signal and the direct current of different frequency and magnitude are applied to the condenser-type membrane sensor 1 whose capacitor capacity varies depending on the position of the sensing electrode 9 which is moved relative to the stationary fixed electrode 3. A signal supply means 23 for supplying a signal containing a component;

The capacitance of the sensing electrode 9 is changed by a specific material reacting with the sensing material applied to the sensing electrode 9 so that the capacitor capacity is changed, or the capacitor capacity is increased by the pressure applied to the sensing electrode 9. A condenser type membrane sensor 1 to be changed;

A signal measuring unit 25 for converting an analog signal output from the membrane sensor 1 into a digital value and increasing data throughput;

The signal supply means 23 is controlled to adjust the frequency and magnitude of the AC signal output from the signal supply means 23, and when the DC component is included, adjust the voltage level of the DC component to be mixed with the AC signal. Adjust the frequency spectrum using the digital value output from the signal measuring unit 25, and generate a frequency spectrum representing the output intensity for each frequency, and detect the difference from a mechanical resonance frequency or a Q-factor difference obtained from the frequency spectrum. Control and signal processing means 27 for measuring the change in mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the electrode 9 and the specific material.

The signal supply means 23 includes an AC voltage generator 29 (PLL: Phase Locked Loop) for varying and outputting an AC voltage frequency according to the control signal of the control and signal processing means 27,

Regulator (31) for generating a DC voltage,

Mixer unit 33 for mixing the AC voltage of the AC voltage generator 29 and the DC voltage of the regulator 31 to supply to the capacitor membrane sensor (1),

A transconductance amplifier 35 for converting the AC voltage and DC voltage mixed by the mixer 33 into an amplified current,

A voltage current selection switch 37 which selects either the voltage output from the mixer 33 or the current output from the transconductance amplifier 35 and supplies it as an AC signal to the condenser-type membrane sensor 1;

It consists of an amplifier 41 for amplifying the AC voltage output from the AC voltage generator 29 to the mixer 33,

The signal measuring unit 25 is an A / D converter 43 for converting an analog signal output from the condenser membrane sensor 1 into a digital signal and outputting digital data in parallel;

A data manipulator and a buffer 45 for storing and arranging digital values converted by the A / D converter 43 to increase data throughput,

The control and signal processing means 27 controls the signal supply means 23 to adjust the frequency and magnitude of the AC signal output from the signal supply means 23 and to adjust the DC signal level mixed with the AC signal, and the signal Control the measuring unit 25 to control the conversion accuracy and data processing speed when converting an analog signal into a digital signal, the sensing electrode 9 by using the digital data from the signal measuring unit 25 through the communication interface 51 When the sensing material applied to the sensing electrode 9 of the condenser type membrane sensor 1 reacts with a specific material, the resonance frequency or Q-factor of the sensing electrode 9 and the sensing When the sensing material applied to the electrode 9 does not react with a specific material, the mass change or reduction of the sensing electrode 9 is performed by using the resonance frequency or the Q-factor change value of the sensing electrode 9. Processor 47 to calculate the pressure applied to the electrode 9;

A display unit 53 for displaying the calculated mass change or pressure;

And a communication interface 51 for sending data to the display unit 53 or the PC 49.

In addition, a signal including an AC signal and a DC component having a different frequency and magnitude is supplied to the contact node of the parasitic components R _ps and C _ps of the sensing electrode 9 and the sensing electrode 9, and the condenser type membrane sensor The output signal of (1) is output from the contact node of the fixed electrode 3 and the sensing electrode 9, or

It is supplied to the contact node of the fixed electrode 3 and the sensing electrode 9 and the output signal of the condenser type membrane sensor 1 is parasitic components R _ps and C _ps of the sensing electrode 9 and the sensing electrode 9. Is output to the contact node of,

The condenser type membrane sensor 1 attaches the fixed electrode 3 of one of the two condenser type membrane sensors 1 to the sensing electrode 9 of the other membrane sensor 1. The sensing electrode 9 of the one membrane sensor 1 is attached to the fixed electrode 3 of the other membrane sensor 1,

The alternating current signal is inputted to a pair of sensing electrodes 9 and fixed electrodes 3 which are attached to each other, and an output signal is measured from the pair of sensing electrodes 9 and fixed electrodes 3 which are stuck to each other. .

In the measuring method for condenser type membrane sensor using the mechanical resonance characteristic of the membrane according to the present invention, a signal including an AC signal and a DC component having a different frequency and magnitude is input to the condenser type membrane sensor 1, and the AC signal and DC The mechanical resonance frequency or the Q-factor of the sensing electrode is obtained from the frequency spectrum of the signal output from the membrane sensor 1 in response to the signal including the component, and the mass change of the sensing electrode 9 or A method of measuring the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 from the mechanical resonance frequency or the Q-factor difference according to the pressure change applied to the sensing electrode, The mechanical resonance frequency of the sensing electrode 9 obtained is a phase among a plurality of frequencies for resonating the sensing electrode 9. Characterized in that the mechanical resonance frequency common to each of the AC signal size.

The magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 compared to a parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1 and having the mechanical resonance frequency. When the AC signal is applied to the membrane sensor 1, it is assumed that the signal of the mechanical resonance frequency is the largest output from the sensing electrode 9.

The measuring method according to the present invention uses various alternating currents to measure the change in mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. When the AC signal having the mechanical resonance frequency and the mechanical resonance frequency of the sensing electrode 9 which are common in the signal magnitude is applied to the membrane sensor 1, the signal of the mechanical resonance frequency is sensed from the sensing electrode 9. In order to find the magnitude of the AC signal to be large output (S1), and to remove the bubble (bubble) generated in the sensing electrode (9) or the material that interferes with the reaction while the sensing electrode 9 reacts with a specific material Vibrating the sensing electrode by using the mechanical resonance characteristics of the sensing electrode (S2), by adding a direct current signal to the AC signal applied to the membrane sensor (1) and then the AC signal Measuring the signal output from the sensing electrode 9 of the membrane sensor 1 while changing the frequency of (S3), to obtain a frequency spectrum based on the signal output from the membrane sensor 1 to obtain a mechanical resonance frequency or Finding the Q-factor (S4), applying to the sensing electrode 9 in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical properties of the membrane sensor (1) And determining the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensed material and the specific material (S5).

The detection, which is common to various AC signal sizes, to measure the change in mass of the sensing electrode 9 and the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. The magnitude of the AC signal which causes the signal of the mechanical resonance frequency to be output the largest from the sensing electrode 9 when an AC signal having the mechanical resonance frequency of the electrode 9 and the mechanical resonance frequency is applied to the membrane sensor 1. Finding step (S1),

Varying the frequency of the signal supplied to the membrane sensor 1,

Varying the magnitude of the signal at each frequency,

Comparing and storing a signal output from the sensing electrode 9 or the fixed electrode 3 when a signal having a frequency and magnitude simultaneously applied to the membrane sensor 1,

Finding a mechanical resonant frequency of the sensing electrode 9 which is common in the magnitude of the signal simultaneously changing the frequency and magnitude among several frequencies for resonating the sensing electrode 9,

And finding the magnitude of the AC signal having the largest output signal of the membrane sensor 1 in the magnitude of the AC signal having the mechanical resonance frequency of the sensing electrode 9,

In step S3 of measuring the signal output from the sensing electrode 9 of the membrane sensor 1 by applying a DC signal to the membrane sensor 1 and then applying it to the membrane sensor 1 by changing the frequency of the AC signal,

Supplying to the membrane sensor 1 while varying the frequency of the DC signal and the AC signal, and measuring the signal output from the sensing electrode 9 of the membrane sensor 1 several times to obtain an average value,

Comparing the average value to the specified value,

Finding a mechanical resonance starting frequency by a bisection method when the average value is larger than a specified value, i.e., when mechanical resonance is started,

And calculating the average value of the signal output from the sensing electrode 9 of the membrane sensor 1 and comparing it with a specified value while finely changing the frequency supplied to the membrane sensor 1 at the mechanical resonance start point.

The measuring device and method for a condenser type membrane sensor using the mechanical resonance frequency according to the present invention firstly, by applying a sufficiently large AC signal to the sensing electrode (9) having a mechanical resonance frequency of the sensing electrode (9) As the displacement of (9) increases, the capacitance change increases, so that the signal output from the sensing electrode 9 also increases, so that the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 than the static method. Can be measured more precisely.

Second, by applying a sufficiently large alternating current signal to the sensing electrode 9 while having a mechanical resonance frequency of the sensing electrode 9, only the sensing electrode 9 is moved largely without moving the parasitic capacitor of the membrane sensor 1. The parasitic condenser effect of the membrane sensor 1 can be greatly reduced, so that the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 can be measured more precisely.

Third, in one measuring device, the AC signal frequency is inputted to the membrane sensor 1 and the signal intensity output from the sensing electrode 9 can be analyzed at that frequency. The frequency characteristic of the sensing electrode 9 can be analyzed.

Fourth, since the mechanical resonance frequency and the Q-factor of the sensing electrode 9 can be obtained from the frequency spectrum of the sensing electrode 9 of the membrane sensor, it is detected from the mechanical resonance frequency or the Q-factor. The mass change of the electrode and the pressure applied to the sensing electrode can be precisely measured.

Fifth, when an AC signal matching the mechanical resonance frequency of the sensing electrode 9 is applied to the membrane sensor 1, the mechanical vibration of the sensing electrode 9 embedded in the membrane sensor 1 increases. By removing the bubbles generated by the sensing electrode 9 reacting with the specific material and the substances that interfere with the reaction, the sensitivity of the membrane sensor 1 can be increased by activating the reaction between the sensing electrode 9 and the specific material. have.

Sixthly, according to the present invention, after reacting a sample of a patient in a state in which a marker for detecting a specific disease is applied to the sensing electrode 9, the mass change of the sensing electrode 9 is measured to determine whether the disease is infected. Since it can be determined, the scanning step essential for the existing biochip disease diagnosis process can be omitted.

Seventh, when the two membrane sensors 1 are connected to each other in the opposite manner and measured by the above method, the voltage from the sensor increases, so that the mass change at the sensing electrode 9 or the pressure applied to the sensing electrode 9 can be precisely measured. can do.

1 is a cross-sectional view of a membrane sensor in which a sensing electrode in contact with a dielectric is moved;

2 is a cross-sectional view of a membrane sensor in which a sensing electrode composed of only a conductor moves;

3 is a block diagram of the present invention;

4 is an electrical equivalent circuit of a condenser type membrane sensor,

5 is a view showing the mechanical resonance characteristics of the condenser type membrane sensor,

6 is a flowchart illustrating a measurement method of a condenser type membrane sensor according to the present invention;

7 is a diagram illustrating vibration characteristics of a sensing electrode according to the frequency and magnitude of an AC signal input to a condenser type membrane sensor;

8 is a flowchart of a method of finding a mechanical resonance frequency of the sensing electrode and an amplitude of an AC signal to sufficiently vibrate the sensing electrode;

9 is a flowchart of a method of finding a frequency at which a sensing electrode of the membrane sensor starts mechanical resonance and a method of changing an AC signal frequency in order to increase the accuracy of the apparatus;

10 is a vibration characteristic of the sensing electrode when the frequency is changed after applying an AC signal of a predetermined size or more to the condenser type membrane sensor,

11 shows that the AC signal and the DC signal are parasitic components of the sensing electrode 9 and the sensing electrode 9.

And

Measuring method, which is supplied to the contact node of the sensor and outputs an output signal from the contact node of the fixed electrode

12 shows that the AC signal and the DC signal are supplied to the fixed electrode 3 of the condenser type membrane sensor 1 and the contact node of the sensing electrode, and the output signal of the condenser type membrane sensor 1 is the sensing electrode 9. And parasitic components of the sensing electrode 9

And

Measuring method to output to contact node of

Figure 13 connects two membrane sensors, connecting the sensing electrode of one membrane sensor to the fixed electrode of the other membrane sensor and the fixed electrode of one membrane sensor to the sensing electrode of the other membrane sensor. To measure the output signal.

* Description of the sign *

1. Condenser type membrane sensor 3. Fixed electrode

9. Detection electrode 11. Rm

13.Cm 15.Rps

17.Cps 19.Rpf

21.Cpf 23. Signal supply means

25. Signal measuring unit 27. Control and signal processing means

29. AC Signal Generator 31. Regulator

33. Mixer Section 35. Transconductance Amplifier

37. Voltage current selection switch 41. Amplifier

43. A / D Converter

45. Data Manipulators and Buffers 47. Processors

49.PC 51.Communication Interface

53. Display

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

The measuring device for condenser type membrane sensor using the mechanical resonance characteristic of the membrane according to the present invention inputs an AC signal and a DC signal while varying the frequency and the size of the condenser type membrane sensor 1, and inputs the AC signal and the DC signal. Correspondingly, the mechanical resonance frequency of the sensing electrode is obtained from the frequency spectrum of the sensing electrode 9 of the membrane sensor 1, and the mass change of the sensing electrode 9 or the sensing electrode 9 at a predetermined magnitude of the input signal. The change in mass or the pressure of the sensing electrode 9 is measured from the difference in the mechanical resonance frequency of the sensing electrode 9 or the difference in the Q-factor according to the change in pressure.

At this time, the magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 compared to the parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1 from the membrane sensor. It is assumed that the output signal is the largest output.

The frequency spectrum measures the signal from the sensing electrode 9 several times while changing the frequency at a specific magnitude of the signal when the AC signal and the DC voltage of which the magnitude and the frequency are respectively changed are input to the condenser type member sensor. The average value of the obtained signal is calculated.

The mechanical resonance frequency of the sensing electrode 9 selects a frequency that is common in each magnitude of the AC signal among a plurality of frequencies for resonating the sensing electrode 9.

The Q-factor of the sensing electrode 9 is

to be.

Here, f ₀ is the mechanical resonance frequency of the sensing electrode 9, m is the mass of the sensing electrode 9,

Is the coefficient of damping factor of the sensing electrode 9.

In addition, the measuring device for the condenser type membrane sensor using the mechanical resonance characteristics of the membrane has a capacitor capacity according to the position of the sensing electrode (9) moving relative to the stationary fixed electrode (3) as shown in FIG. A signal supply means 23 for supplying a changing capacitor type membrane sensor 1 with a signal including an AC signal and a DC component having a different frequency and size, and a specific material reacting with a sensing material applied to the sensing electrode 9. Capacitive membrane sensor 1 and the membrane sensor 1 in which the capacitance of the sensing electrode 9 is changed by a material and thus the capacitor capacitance is changed, or the capacitor capacitance is changed by the pressure applied to the sensing electrode 9. The signal measuring unit 25 converts the analog signal outputted from the digital signal into a digital value and increases the data throughput, and controls the signal supply means 23 to the signal supply means 23. Adjust the frequency and magnitude of the AC signal output from the, adjust the voltage level of the DC component to be mixed with the AC signal when the DC component is included, and uses the digital value output from the signal measuring unit 25 A frequency spectrum representing an output intensity for each frequency, and a reaction between a specific material and a sensing material applied to the sensing electrode 9 from a resonance frequency difference or a Q-factor difference obtained from the frequency spectrum. Control and signal processing means 27 for measuring the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9.

The signal supply means 23 includes an AC voltage generator 29 (PLL: Phase Locked Loop) for varying and outputting an AC voltage frequency according to the control signal of the control and signal processing means 27, and a regulator for generating a DC voltage. (31) includes a mixer 33 for mixing the AC voltage of the AC voltage generator 29 with the DC voltage of the regulator 31 and supplying the condenser-type membrane sensor 1.

In addition, the signal supply means 23 is a transconductance amplifier 35 for converting the alternating voltage and the direct current voltage mixed by the mixer unit 33 into an amplified current, and the voltage output from the mixer unit 33 It further includes a voltage current selection switch 37 which selects any one of the currents output from the transconductance amplifier 35 and supplies it to the condenser-type membrane sensor 1 as an AC signal.

In addition, the signal supply means 23 further includes an amplifier 41 which amplifies the AC voltage output from the AC voltage generator 29 and transmits the amplified voltage to the mixer 33.

The signal measuring unit 25 is an A / D converter 43 for converting an analog signal output from the condenser membrane sensor 1 into a digital signal and outputting digital data, and by the A / D converter 43. The data manipulator and the buffer 45 may be configured to store and organize the converted digital values to increase data throughput.

The A / D converter 43 uses a parallel A / D converter that outputs output data in parallel to increase the conversion speed.

The control and signal processing means 27 controls the signal supply means 23 to adjust the frequency and magnitude of the AC signal output from the signal supply means 23 and to adjust the DC signal level mixed with the AC signal, and the signal Control the measuring unit 25 to control the conversion accuracy and data processing speed when converting an analog signal into a digital signal, the sensing electrode 9 by using the digital data from the signal measuring unit 25 through the communication interface 51 When the sensing material applied to the sensing electrode 9 of the condenser type membrane sensor 1 reacts with a specific material, the resonance frequency or Q-factor of the sensing electrode 9 and the sensing When the sensing material applied to the electrode 9 does not react with a specific material, the mass change or reduction of the sensing electrode 9 is performed by using the resonance frequency or the Q-factor change value of the sensing electrode 9. A processor 47 for calculating the pressure applied to the electrode 9, a display unit 53 for displaying the calculated mass change or pressure, and a communication interface 51 for sending data to the display unit 53 or the PC 49. ).

On the other hand, the measuring method for the condenser-type membrane sensor using the mechanical resonance characteristics of the membrane according to the present invention is a sensing electrode (9) having an intensity capable of vibrating the sensing electrode (9) in the condenser-type membrane (membrane) sensor (1) The change of mass of the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and the specific material by increasing the mechanical displacement of the sensing electrode 9 by applying an AC signal and a DC signal of a mechanical resonance frequency of The pressure applied to the sensing electrode 9 is precisely measured.

Modeling the condenser-type membrane sensor (circuit) sensor (membrane) as shown in Figure 4 (modeling).

In FIG. 4, Rm 11 is a series resistance of the sensing electrode 9, Cm 13 is a capacitance of the sensing electrode 9, and Rps 15 is a parasitic resistance from the sensing electrode 9 to ground.

In addition, Cps 17 is the parasitic capacitance from the sensing electrode 9 to the ground, Rpf 19 is the parasitic resistance from the fixed electrode 3 to the ground, and Cpf 21 is the ground at the fixed electrode 3. Up to parasitic capacity.

In general, the capacitance change of the sensing electrode 9 (

) Is much smaller than the parasitic capacitances such as Cps (17) and Cpf (21), so it is difficult to measure very small mass or low pressure in a static way when measuring very small mass changes or low pressure.

On the other hand, using a laser vibrometer (Laser Vibrometer) to measure the displacement of the sensing electrode 9 of the capacitor-type membrane sensor (1) according to the frequency as shown in Figure 5. It can be seen from FIG. 5 that the displacement of the sensing electrode 9 increases near the mechanical resonance frequency.

Therefore, if the frequency of the measuring AC signal for measuring the capacitor capacitance of the condenser type membrane sensor 1 matches the mechanical resonance frequency of the sensing electrode 9, the displacement of the sensing electrode 9 becomes large and the sensing electrode 9 is increased. The change in the capacitor capacity (Cm (13)) of the can also be increased to reduce the influence of parasitic capacitance such as Cps (17) and Cpf (21).

On the other hand, the measurement method for the condenser-type membrane sensor using the mechanical resonance characteristics of the membrane according to the present invention using the principle that the displacement of the membrane is large when the AC signal is matched to the mechanical resonance frequency of the membrane and a predetermined size is applied to the membrane. After applying an alternating current signal having a mechanical resonance frequency of sufficient magnitude to vibrate the sensing electrode 9 of the sensor 1 to the membrane sensor 1, the sensing material applied to the sensing electrode 9 is a specific material. The change in the mass of the sensing electrode is measured using a change in the mechanical resonance frequency or the Q-factor of the sensing electrode 9 according to the presence or absence of the reaction, or the pressure applied to the sensing electrode 9 is measured.

On the other hand, the measurement method for the condenser type membrane sensor using the mechanical resonance characteristics of the membrane inputs a signal containing an AC signal and a DC component having a different frequency and magnitude into the capacitor type membrane sensor (1), and the AC signal and the DC component The mechanical resonance frequency of the sensing electrode is obtained from the frequency spectrum of the sensing electrode 9 of the membrane sensor 1 in response to the included signal, and the sensing electrode (at a predetermined magnitude of the signal including the AC signal and the DC component) is measured. The mass change or the pressure of the sensing electrode 9 is measured from the difference in the mechanical resonance frequency or the difference in the Q-factor according to the mass change of 9) or the pressure applied to the sensing electrode 9.

The mechanical resonance frequency of the sensing electrode 9 is assumed to be common in each magnitude of the AC signal among a plurality of frequencies for resonating the sensing electrode 9.

In this case, the predetermined magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 compared to a parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1. The signal output from the largest output.

In addition, the Q-factor of the sensing electrode 9 is

to be.

Here, f ₀ is the mechanical resonance frequency of the sensing electrode, m is the mass of the sensing electrode,

Is the coefficient of damping factor of the sensing electrode 9.

In addition, as shown in FIG. 6, the measurement method may be performed by changing the mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. The mechanical resonance frequency of the sensing electrode 9 and the AC signal having the mechanical resonance frequency, which are common to various AC signal sizes, are measured from the sensing electrode 9 when the AC sensor is applied to the membrane sensor 1 for measurement. In order to find the magnitude of the alternating signal (S1) which causes the signal of the resonant frequency to be output the largest (S1), and to remove the bubble (bubble) or the material that interferes with the reaction when the sensing electrode (9) reacts with a specific material Vibrating the sensing electrode 9 by using the mechanical resonance characteristics of the sensing electrode (9) (S2), a direct current signal is added to the alternating current signal and applied to the membrane sensor (1) and then the alternating current signal Measuring the signal output from the sensing electrode 9 of the membrane sensor 1 while varying the frequency (S3), obtain a frequency spectrum based on the signal output from the membrane sensor 1 to obtain a mechanical resonance frequency or performance Finding the Q factor (S4), the change in the mechanical resonant frequency or performance factor (Q-factor) and the structure and physical properties of the membrane sensor 1 is applied to the sensing electrode 9 in consideration of And determining the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensed material and the specific material (S5).

On the other hand, when an AC signal is applied to the sensing electrode 9 or the fixed electrode 3 of the condenser-type membrane sensor 1, mechanical vibration may occur, but when the magnitude of the AC signal is small, it may not vibrate to a desired level. .

In addition, since the sensing electrode 9 of the condenser-type membrane sensor 1 resonates at various frequencies, when an AC signal having a sufficient magnitude is applied to the sensing electrode 9, as shown in FIG. Will cause mechanical vibrations of different magnitudes.

In order to measure the change in the mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material and the specific material on the sensing electrode 9 by using the resonance frequency of the sensing electrode 9, The reliability of the measurement should be increased by using the common resonance frequency that is common in voltage.

The magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 compared to the parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1 and having the mechanical resonance frequency. When the AC signal is applied to the membrane sensor 1, it is assumed that the signal of the mechanical resonance frequency is the largest output from the sensing electrode 9.

The detection, which is common to various AC signal sizes, to measure the change in mass of the sensing electrode 9 and the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. The magnitude of the AC signal which causes the signal of the mechanical resonance frequency to be output the largest from the sensing electrode 9 when an AC signal having the mechanical resonance frequency of the electrode 9 and the mechanical resonance frequency is applied to the membrane sensor 1. Finding step (S1) is the step of changing the frequency of the signal supplied to the membrane sensor 1, the step of changing the magnitude of the signal at each frequency, the signal simultaneously changing the frequency and magnitude to the membrane sensor (1) Comparing and storing the signal output from the sensing electrode 9 or the fixed electrode 3 when applied, the frequency among the various frequencies that resonate the sensing electrode 9 Finding the mechanical resonance frequency of the sensing electrode 9 which is common in the magnitude of the signal having the same size at the same time, and in the magnitude of the AC signal having the mechanical resonance frequency of the sensing electrode 9, the output signal of the membrane sensor is the largest. Finding the magnitude of the AC signal.

The detection, which is common to various AC signal sizes, to measure the change in mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. The magnitude of the AC signal which causes the signal of the mechanical resonance frequency to be output the largest from the sensing electrode 9 when an AC signal having the mechanical resonance frequency of the electrode 9 and the mechanical resonance frequency is applied to the membrane sensor 1. Finding step (S1) can be described in more detail with reference to FIG.

The DC signal is added to the AC signal and applied to the membrane sensor 1, and then the signal output from the sensing electrode 9 of the membrane sensor 1 is measured while changing the frequency of the AC signal (S3). Supplying to the membrane sensor 1 while varying the frequency of the AC signal and measuring the signal output from the sensing electrode 9 of the membrane sensor 1 several times to obtain an average value, and comparing the average value with a specified value. When the average value is larger than the specified value, that is, when the mechanical resonance is started, finding the mechanical resonance starting frequency by a bisection method, and changing the frequency supplied to the membrane sensor 1 at the mechanical resonance starting point finely. Comprising a step of obtaining the average value of the signal output from the sensing electrode (9) of the sensor 1 and comparing it with the specified value.

Step S3 of measuring the signal output from the sensing electrode 9 of the membrane sensor 1 while applying the DC signal to the membrane sensor 1 by applying the AC signal to the membrane sensor 1 and then changing the frequency of the AC signal is shown in FIG. 9. It may be described in more detail through.

Finding a mechanical resonance frequency and a Q-factor by obtaining a frequency spectrum based on the signal output from the membrane sensor 1 (S4) is a frequency spectrum of the sensing electrode (9) using Equation 5 Configuring, finding a mechanical resonance frequency of the sensing electrode 9 in which the signal of the highest magnitude appears in the frequency spectrum, and calculating a performance coefficient of the sensing electrode 9 using Equation 6 in the frequency spectrum. It is composed.

remind

Is the starting frequency of the frequency spectrum,

Is the end frequency of the frequency spectrum,

Is the width of the frequency change of the AC signal,

Is the peak value of the signal output from the membrane sensor 1.

In equation (5)

The term increases to the mechanical resonance frequency of the sensing electrode 9 when it is assumed that the frequency is increased, but since the vibration of the sensing electrode 9 decreases after the mechanical resonance frequency, the output signal peaks at the mechanical resonance frequency. The spectrum can be obtained.

The Q-factor represented by Equation 6 is defined in the frequency spectrum as follows.

Is the mechanical resonance frequency of the sensing electrode 9

Denotes a frequency band 1/2 of the peak power centered on the mechanical resonance frequency representing the peak power.

A sensing electrode due to a reaction between a sensing material applied to the sensing electrode 9 and a specific material in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical characteristics of the membrane sensor 1) Determining the mass change of the 9 or the pressure applied to the sensing electrode 9 (S5) is a change in the mechanical resonance frequency of the sensing electrode 9 (

) And the formula

Mass change of the sensing electrode 9 due to the reaction between the sensing material and the specific material applied to the sensing electrode 9 using

Measure

In addition, in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical properties of the membrane sensor 1, the detection due to the reaction between the specific material and the sensing material applied to the sensing electrode 9 Determining the change in the mass of the electrode 9 or the pressure applied to the sensing electrode 9 (S5) is a change in the Q-factor of the sensing electrode 9 and a formula.

Mass change of the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material using

Measure

Assuming that the sensing electrode 9 of the membrane sensor 1 is a mass-spring system, the mass change of the sensing electrode 9 (

Variation of Mechanical Resonance Frequency According to

) Can be expressed as shown in Equation-7.

By performing some mathematical manipulation using Equation-7, Equation-8 can be obtained.

In Equation 7

Is the area of the electrode,

Is the mass of the sensing electrode 9,

Is the mechanical resonant frequency of the sensing electrode 9.

Also,

Is the density of the membrane sensor 1,

Is the thickness of the membrane sensor 1.

Equation (8) shows a change in mass of the sensing electrode 9 when the sensing material applied to the sensing electrode 9 reacts with a specific material.

Variation of Mechanical Resonance Frequency According to

Where the mechanical resonant frequency (

) Is known in the above method, so the change in mechanical resonance frequency (

), The mass change of the sensing electrode 9 according to the reaction of the sensing material and the specific material applied to the sensing electrode 9

) Can be obtained.

In Equation 3,

Is the coefficient according to the shape of the sensing electrode,

'Is the thickness of the material attached to the sensing electrode 9,' d 'is the radius when the sensing electrode (9) is spherical, the length of one side when the square,'

'Means density of the material attached to the sensing electrode 9.

Also, the above '

Is the Young's modulus of the sensing electrode 9,

Is the Poisson's ratio of the electrode,

Is the mechanical resonance frequency of the sensing electrode 9.

The Young's modulus is an elastic modulus representing the relationship between the deformation occurring in the object and the pressure applied to the sensing electrode 9, so it is detected by using the mechanical resonance frequency of the sensing electrode 9 mounted on the condenser type membrane sensor. The pressure applied to the electrode 9 can be measured.

The Q-factor of the membrane structure is expressed as in Equation 4. The density of the membrane in (4)

)

It is represented as Where m is the mass of the sensing electrode, t is the thickness of the sensing electrode, and A is the area of the sensing electrode. density(

)

And substituting Equation 3, which represents the mechanical resonance frequency, into Equation 4, differentiate the performance coefficient Q by mass, and then obtain Equation 9.

In Equation 9

Is the change in Q-factor,

Is the change in mass of the sensing electrode,

Is the mass of the sensing electrode.

In Equation 4, f ₀ is a mechanical resonance frequency of the sensing electrode 9 represented by Equation 3, which is represented by Equation 3, where m is the mass of the sensing electrode,

Is the coefficient of damping factor of the sensing electrode 9.

The mechanical resonance frequency of the sensing electrode 9 included in Equation 4, which represents the Q-factor of the membrane electrode, includes Young's modulus. Since it is an elastic modulus representing the relationship between the deformation occurring and the pressure applied to the sensing electrode 9, the Q-factor of the sensing electrode 9 mounted on the condenser-type membrane sensor is applied to the sensing electrode 9. The pressure can be measured.

In Equation 3, 'k _g ' is a coefficient according to the shape of the sensing electrode, 't' is the thickness of the material attached to the sensing electrode 9, 'd' is a case where the sensing electrode 9 is spherical Radius and square, the length of one side,

'Means density of the material attached to the sensing electrode 9.

Also, '

When the AC signal of the magnitude obtained in step S1 is applied to the condenser-type membrane sensor 1 and the voltage of the sensing electrode 9 or the fixed electrode 3 is measured while changing the frequency, the frequency characteristics as shown in FIG. 10 are shown.

As shown in FIG. 10, the signal amplitude does not change in the frequency region where the mechanical resonance of the condenser type membrane sensor 1 does not occur, whereas the sensing electrode 9 does not change in the frequency region where the mechanical resonance of the sensing electrode 9 occurs. The larger the displacement of, the larger the change in the capacitance of the capacitor of the sensing electrode 9 and the greater the variation of the voltage output from the membrane sensor 1.

By using this characteristic, the frequency of the AC signal output from the signal supply means 23 is greatly changed in the frequency region where mechanical resonance does not occur, that is, in the region where the signal variation output from the sensing electrode 9 of the membrane sensor 1 is small. A / D conversion of the signal output from the sensing electrode 9 of the condenser type membrane sensor 1 is performed.

On the other hand, in the frequency region where mechanical resonance occurs, that is, in the region where the signal fluctuation output from the sensing electrode 9 of the membrane sensor 1 is large, the frequency of the AC signal output from the signal supply means 23 is changed finely to condenser type. The signal output from the membrane sensor 1 is A / D converted.

In addition, in the region where the signal output from the sensing electrode 9 of the condenser-type membrane sensor 1 is small, that is, in the frequency region deviating from mechanical resonance, the frequency change of the AC signal output from the signal supply means 23 is increased to increase the A / D. Convert.

As shown in FIG. 11, the AC signal and the DC signal having the mechanical resonance frequency of the sensing electrode 9 are parasitic components of the sensing electrode 9 and the sensing electrode.

And

And the output signal of the condenser type membrane sensor 1 may be output from the fixed node 3 and the contact node of the sensing electrode.

In addition, the input signal of the condenser type membrane sensor 1 is supplied to the contact node of the fixed electrode 3 and the sensing electrode 9 as shown in FIG. 12, and the output signal of the condenser type membrane sensor 1 is provided. Is a parasitic component of the sensing electrode 9 and the sensing electrode 9

And

) Can be output to a contact node.

As shown in FIG. 13, two membrane sensors 1 are attached, and the fixed electrode 3 of one membrane sensor 1 is replaced by the sensing electrode 9 of the other membrane sensor 1. And attach the sensing electrode 9 of one membrane sensor 1 to the fixed electrode 3 of the other membrane sensor 1, and then attach a pair of sensing electrodes 9 and the fixed electrode which are stuck together. An alternating current signal may be input to (3), and the output signal may be measured from another pair of sensing electrodes 9 and fixed electrodes 3.

The measuring apparatus and method for condenser type membrane sensor using the mechanical resonance characteristic of the membrane according to the present invention firstly, by applying a sufficiently large AC signal to the sensing electrode 9 having a mechanical resonance frequency of the sensing electrode 9 As the displacement of the sensing electrode 9 increases, the change in capacitance increases, so that the signal output from the sensing electrode 9 also increases, so that the mass change of the sensing electrode 9 or the sensing electrode 9 does not affect the static method. The pressure applied can be measured more precisely.

Third, the signal intensity output from the sensing electrode 9 of the membrane sensor 1 can be analyzed at the same time as the AC signal frequency is inputted to the membrane sensor 1 in one measuring device. Therefore, the frequency characteristics of the sensing electrode 9 can be analyzed without an expensive spectral device.

Fifth, when an AC signal matching the mechanical resonance frequency of the sensing electrode 9 is applied to the membrane sensor 1, the mechanical vibration of the sensing electrode 9 embedded in the membrane sensor 1 increases. By removing the material that interferes with the bubble or half generated by the sensing electrode 9 reacting with the specific material, the sensitivity of the membrane sensor 1 can be increased by activating the reaction between the sensing electrode 9 and the specific material. have.

Sixthly, according to the present invention, after reacting a sample of a patient in a state in which a marker for detecting a specific disease is applied to the sensing electrode 9, the mass change of the sensing electrode 9 is measured to determine whether the disease is infected. As a result, the scan step necessary for the existing biochip disease diagnosis process can be omitted.

Seventhly, two membrane sensors 1 were connected to each other oppositely. When the measurement is made in the above manner, the voltage from the sensor increases, so that the mass change in the sensing electrode 9 and the pressure applied to the sensing electrode 9 can be accurately measured.

Claims

An AC signal and a DC signal are input to the condenser type membrane sensor 1 while varying the frequency and the magnitude, respectively, and in response to the AC signal and the DC signal, the frequency spectrum of the sensing electrode 9 of the membrane sensor 1 The mechanical resonance frequency of the sensing electrode is obtained, and the difference in the mechanical resonance frequency of the sensing electrode 9 according to the change in the mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 at a predetermined magnitude of the input signal. Alternatively, the mass change or the pressure of the sensing electrode 9 is measured from the difference in the Q-factor,

The magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 as compared with the parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1 and is output from the membrane sensor. To output the largest signal,

The frequency spectrum measures the signal from the sensing electrode 9 several times while changing the frequency at a specific magnitude of the signal when the AC signal and the DC voltage of which the magnitude and the frequency are respectively changed are input to the condenser type member sensor. Measuring device for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that it is calculated from the average value of the signal obtained by.
The method of claim 1,

The mechanical resonance frequency of the sensing electrode 9 selects a frequency that is common to each magnitude of the AC signal among a plurality of frequencies for resonating the sensing electrode 9. Measuring device for type membrane sensor.
The method of claim 1,

The Q-factor of the sensing electrode 9 is
Measuring device for condenser type membrane sensor using the mechanical resonance characteristics of the membrane.

here,

f 0 is the mechanical resonance frequency of the sensing electrode 9,

m is the mass of the sensing electrode 9,

Is the coefficient of damping factor of the sensing electrode 9
Supplying a signal including an AC signal and a DC component having a different frequency and magnitude to the condenser type membrane sensor 1 whose capacitor capacity varies depending on the position of the sensing electrode 9 that moves relative to the stationary fixed electrode 3. A signal supply means 23 for performing;

The capacitance of the sensing electrode 9 is changed by a specific material reacting with the sensing material applied to the sensing electrode 9 so that the capacitor capacity is changed, or the capacitor capacity is increased by the pressure applied to the sensing electrode 9. A condenser type membrane sensor 1 to be changed;

A signal measuring unit 25 for converting an analog signal output from the membrane sensor 1 into a digital value and increasing data throughput;

The signal supply means 23 is controlled to adjust the frequency and magnitude of the AC signal output from the signal supply means 23, and when the DC component is included, adjust the voltage level of the DC component to be mixed with the AC signal. Adjust the frequency spectrum using the digital value output from the signal measuring unit 25, and generate a frequency spectrum representing the output intensity for each frequency, and detect the difference from a resonance frequency difference or a Q-factor difference obtained from the frequency spectrum. Control and signal processing means 27 for measuring the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the electrode 9 and a specific material;

The frequency spectrum measures the signal from the sensing electrode 9 several times while changing the frequency at a specific magnitude of the signal when the AC signal and the DC voltage of which the magnitude and the frequency are respectively changed are input to the condenser type member sensor. Measuring device for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that it is calculated from the average value of the signal obtained by.
The method of claim 4, wherein

The signal supply means 23 includes an AC voltage generator 29 (PLL: Phase Locked Loop) for varying and outputting an AC voltage frequency according to the control signal of the control and signal processing means 27,

Regulator (31) for generating a DC voltage,

Mixer unit 33 for mixing the AC voltage of the AC voltage generator 29 and the DC voltage of the regulator 31 to supply to the capacitor membrane sensor (1),

A transconductance amplifier 35 for converting the AC voltage and DC voltage mixed by the mixer 33 into an amplified current,

A voltage current selection switch 37 which selects either the voltage output from the mixer 33 or the current output from the transconductance amplifier 35 and supplies it as an AC signal to the condenser-type membrane sensor 1;

Measuring device for the condenser-type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that consisting of amplification unit 41 for amplifying the alternating voltage output from the alternating voltage generator 29 to the mixer 33.
The method of claim 4, wherein

The signal measuring unit 25 is an A / D converter 43 for converting an analog signal output from the condenser membrane sensor 1 into a digital signal and outputting digital data in parallel;

Measurement for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that it comprises a data manipulator and a buffer 45 for storing and arranging the digital value converted by the A / D converter 43 to increase the data throughput Device.
The method of claim 4, wherein

The control and signal processing means 27 controls the signal supply means 23 to adjust the frequency and magnitude of the AC signal output from the signal supply means 23 and to adjust the DC signal level mixed with the AC signal, and the signal Control the measuring unit 25 to control the conversion accuracy and data processing speed when converting an analog signal into a digital signal, the sensing electrode 9 by using the digital data from the signal measuring unit 25 through the communication interface 51 When the sensing material applied to the sensing electrode 9 of the condenser type membrane sensor 1 reacts with a specific material, the resonance frequency or Q-factor of the sensing electrode 9 and the sensing When the sensing material applied to the electrode 9 does not react with a specific material, the mass change or reduction of the sensing electrode 9 is performed by using the resonance frequency or the Q-factor change value of the sensing electrode 9. Processor 47 to calculate the pressure applied to the electrode 9;

A display unit 53 for displaying the calculated mass change or pressure;

And a communication interface (51) for sending data to the display unit (53) or the PC (49).
The method of claim 4, wherein

A signal including an AC signal and a DC component having a different frequency and magnitude is supplied to the contact node between the sensing electrode 9 and the parasitic components R ps and C ps of the sensing electrode 9, and the condenser type membrane sensor 1 Output signal is output from the contact node of the fixed electrode (3) and the sensing electrode (9),

It is supplied to the contact node of the fixed electrode 3 and the sensing electrode 9 and the output signal of the condenser type membrane sensor 1 is parasitic components R ps and C ps of the sensing electrode 9 and the sensing electrode 9. Measuring device for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that output to the contact node.
The method of claim 4, wherein

The condenser type membrane sensor 1 attaches the fixed electrode 3 of one of the two condenser type membrane sensors 1 to the sensing electrode 9 of the other membrane sensor 1. The sensing electrode 9 of the one membrane sensor 1 is attached to the fixed electrode 3 of the other membrane sensor 1,

Inputting the alternating current signal to any pair of sensing electrodes 9 and fixed electrodes 3 adjoining each other and measuring the output signal from the other pair of sensing electrodes 9 and fixed electrodes 3 adjoining each other Measuring device for condenser type membrane sensor using the mechanical resonance characteristics of the membrane.
A signal including an AC signal and a DC component having a different frequency and magnitude is input to the capacitor-type membrane sensor 1, and the sensing electrode 9 of the membrane sensor 1 is corresponding to the signal including the AC signal and the DC component. The mechanical resonance frequency of the sensing electrode 9 is obtained from the frequency spectrum of Δ, and the mass change of the sensing electrode 9 or the pressure applied to the sensing electrode 9 at a predetermined magnitude of the signal including the AC signal and the DC component. The mass change or pressure of the sensing electrode 9 is measured from the difference of the mechanical resonance frequency or the difference of the Q-factor according to the change,

The predetermined magnitude of the AC signal is a magnitude capable of detecting a change in capacitance due to vibration of the sensing electrode 9 compared to a parasitic capacitance generated by the structure and physical characteristics of the membrane sensor 1. By outputting the largest output signal,

The frequency spectrum measures the signal from the sensing electrode 9 several times while changing the frequency at a specific magnitude of the signal when the AC signal and the DC voltage of which the magnitude and the frequency are respectively changed are input to the condenser type member sensor. Measuring method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that it is calculated from the average value of the signal obtained by.
The method of claim 10,

The mechanical resonance frequency of the sensing electrode 9 is measured for the condenser-type membrane sensor using the mechanical resonance characteristic of the membrane, which is common to each magnitude of the AC signal among a plurality of frequencies for resonating the sensing electrode 9. Way.
The method of claim 10,

The Q-factor of the sensing electrode 9 is
Measuring method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane.

here,

f 0 is the mechanical resonance frequency of the sensing electrode 9,

m is the mass of the sensing electrode 9,

Is the coefficient of damping factor of the sensing electrode 9
The method according to any one of claims 10 to 12,

The measuring method is common in various AC signal sizes in order to measure the change in mass of the sensing electrode 9 or the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. When the AC signal having the mechanical resonance frequency and the mechanical resonance frequency of the sensing electrode 9 to the membrane sensor 1 is applied to cause the signal of the mechanical resonance frequency to be the largest output from the sensing electrode 9 Finding the magnitude of the AC signal (S1),

In order to remove bubbles generated from the sensing electrode 9 or a material that interferes with the reaction while the sensing electrode 9 reacts with a specific material, the sensing electrode 9 may be formed using a mechanical resonance characteristic of the sensing electrode 9. 9) vibrating (S2),

Measuring the signal output from the sensing electrode 9 of the membrane sensor 1 while applying a DC signal to the AC signal and applying the DC signal to the membrane sensor 1 and then changing the frequency of the AC signal (S3),

Finding a mechanical resonance frequency or a Q-factor by obtaining a frequency spectrum based on the signal output from the membrane sensor 1 (S4),

A sensing electrode due to a reaction between a sensing material applied to the sensing electrode 9 and a specific material in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical characteristics of the membrane sensor 1) A method for measuring condenser type membrane sensors using a mechanical resonance characteristic of the membrane, characterized in that it comprises the step (S5) of determining the change in mass or the pressure applied to the sensing electrode (9).
The method of claim 13,

The detection, which is common to various AC signal sizes, to measure the change in mass of the sensing electrode 9 and the pressure applied to the sensing electrode 9 due to the reaction between the sensing material applied to the sensing electrode 9 and a specific material. The magnitude of the AC signal which causes the signal of the mechanical resonance frequency to be output the largest from the sensing electrode 9 when an AC signal having the mechanical resonance frequency of the electrode 9 and the mechanical resonance frequency is applied to the membrane sensor 1. Finding step (S1),

Varying the frequency of the signal supplied to the membrane sensor 1,

Varying the magnitude of the signal at each frequency,

Comparing and storing a signal output from the sensing electrode 9 or the fixed electrode 3 when a signal having a frequency and magnitude simultaneously applied to the membrane sensor 1,

Finding a mechanical resonant frequency of the sensing electrode 9 which is common in the magnitude of the signal simultaneously changing the frequency and magnitude among several frequencies for resonating the sensing electrode 9,

And finding the magnitude of the AC signal having the largest output signal of the membrane sensor 1 in the magnitude of the AC signal having the mechanical resonant frequency of the sensing electrode 9 using the mechanical resonance characteristic of the membrane. Measurement method for condenser type membrane sensor.
The method of claim 13,

In step S3 of measuring the signal output from the sensing electrode 9 of the membrane sensor 1 by applying a DC signal to the membrane sensor 1 and then applying it to the membrane sensor 1 by changing the frequency of the AC signal,

Supplying to the membrane sensor 1 while varying the frequency of the DC signal and the AC signal, and measuring the signal output from the sensing electrode 9 of the membrane sensor 1 several times to obtain an average value,

Comparing the average value to the specified value,

Finding a mechanical resonance starting frequency by a bisection method when the average value is larger than a specified value, i.e., when mechanical resonance is started,

And obtaining a mean value of the signal output from the sensing electrode 9 of the membrane sensor 1 and comparing the specified value with a minute change in the frequency supplied to the membrane sensor 1 at the mechanical resonance start point. Measuring method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane.
The method of claim 13,

The step (S4) of finding a mechanical resonance frequency or a Q-factor by obtaining a frequency spectrum based on a signal output from the sensing electrode 9 of the membrane sensor 1,

Equation
Configuring the frequency spectrum of the sensing electrode 9 by using;

Finding a mechanical resonance frequency of the sensing electrode 9 in which the signal of the highest magnitude appears in the frequency spectrum, or

Formula in the frequency spectrum
Measuring method for the condenser-type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that it comprises the step of obtaining the performance coefficient of the sensing electrode (9).

here,

Is the starting frequency of the frequency spectrum,

: End frequency of the frequency spectrum,

Is the frequency change of the AC signal,

: Peak value of the signal output from the membrane sensor 1,

: Mechanical resonance frequency of the sensing electrode (9),

: Frequency band that is 1/2 of peak power centered on the mechanical resonance frequency representing peak power

: Coefficient of performance of the sensing electrode 9
The method of claim 13,

A sensing electrode due to a reaction between a sensing material applied to the sensing electrode 9 and a specific material in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical characteristics of the membrane sensor 1) Determining the mass change of the 9) or the pressure applied to the sensing electrode (9) (S5),

Change of Mechanical Resonance Frequency of Sensing Electrode (
) And the formula
Mass change of the sensing electrode due to the reaction between the sensing material and the specific material applied to the sensing electrode 9 using
) Or

Changes and equations of Q-factor of sensing electrode
Mass change of the sensing electrode due to the reaction between the sensing material and the specific material applied to the sensing electrode 9 using
Measurement method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that the measurement.

here,

: Resonant frequency of the sensing electrode 9,

: The mass of the sensing electrode 9,

: Mass of a specific material reacted with a sensing material applied to the sensing electrode 9,

: Change in the mechanical resonance frequency of the sensing electrode 9 when a specific material reacts with the sensing material applied to the sensing electrode 9

: Change in Q-factor of the sensing electrode 9 when a specific material reacts with the sensing material applied to the sensing electrode 9

: Q-factor of the sensing electrode 9
The method of claim 13,

A sensing electrode due to a reaction between a sensing material applied to the sensing electrode 9 and a specific material in consideration of the change in the mechanical resonance frequency or Q-factor and the structure and physical characteristics of the membrane sensor 1) Determining the mass change of the 9) or the pressure applied to the sensing electrode (9) (S5),

Equation
Using to measure the pressure applied to the sensing electrode (9),

Equation
Wow
Measuring method for condenser type membrane sensor using the mechanical resonance characteristics of the membrane, characterized in that for measuring the pressure by using a.

here,

: Coefficient according to shape of sensing electrode,

t is the thickness of the material attached to the sensing electrode 9,

d is the radius when the sensing electrode 9 is spherical and the length of one side when the square is square,

: Density of the material attached to the sensing electrode 9,

: Young's modulus of the sensing electrode 9,

E: Poisson's ratio of the electrode,

f 0: mechanical resonance frequency of the sensing electrode 9,

m is the mass of the sensing electrode,

: Coefficient of damping factor of the sensing electrode 9