Coupled array sensor and method for simultaneous identification and detection of multiple trace substances

Abstract

This invention belongs to the field of mass sensing technology, and particularly relates to a coupled array sensor and method for simultaneous identification and detection of multiple trace substances. A micro-actuator is fixed to the bottom of a base, and multiple low-frequency resonant units are located on the top of the base. A high-frequency resonant unit is located on the base to the right of each low-frequency resonant unit. Specific adsorption films are deposited on the right end of each low-frequency resonant unit and at both ends of the high-frequency resonant unit. A micro-transducer is fixed to the high-frequency resonant unit. Part of the coupling unit is fixed to the low-frequency resonant unit, and the other part is fixed to the high-frequency resonant unit. By utilizing the resonance between the coupled resonant arrays composed of multiple resonant units, the mass information of multiple analytes is converged onto the amplitude-frequency characteristic curve of a single high-frequency resonant unit, achieving single-input single-output, synchronous, and high-precision identification and detection of multiple substances. This greatly simplifies the output circuit and amplifies the sensitivity, achieving low-power, low-cost, and high-precision simultaneous identification and detection of multiple substances.

Description

Technical Field

[0001] This invention belongs to the field of mass sensing technology, and in particular relates to a coupled array sensor and method for simultaneous identification and detection of multiple trace substances. Background Technology

[0002] With the development of science and technology, people's living standards are constantly improving. However, in recent years, many problems such as environmental pollution, disease prevention, and public safety have emerged. To solve these problems, it is crucial to detect and issue early warnings for trace pollutants, explosives, and small biological molecules. Sensors that can be used for the detection of minute masses can be mainly classified into several categories, including electrical, electrochemical, optical, and resonant beam sensors. Among them, resonant beam sensors have been widely used in fields such as mass (gas, virus, cell, biomolecule, etc.) sensing, force sensing, and electromagnetic field sensing due to their high stability, simple structure, ease of integration, small size, and low cost. However, the sensing performance of resonant sensors is limited by various factors such as resonant frequency, quality factor, vibration intensity, and noise. To address this, researchers from various countries have done a lot of work from both engineering and theoretical perspectives. In engineering, ultra-low temperature sensing, vacuum packaging, and feedback excitation are mainly used to improve sensing performance. In principle, the sensing resolution is mainly improved by applying residual stress, mechanical sideband excitation, parameter amplification, and phase synchronization, and sensitivity amplification is achieved by utilizing nonlinear vibration principles such as Davin bifurcation, parametric resonance, synchronous resonance, and internal resonance in single or coupled micro / nanomechanical systems. Although the above work has made breakthroughs in the detection of single trace substances from an engineering or physical perspective, the simultaneous identification and detection of multiple trace substances still presents significant challenges. Summary of the Invention

[0003] To overcome the above problems, this invention provides a coupled array sensor and method for simultaneous identification and detection of multiple trace substances. The aim is to utilize the internal resonance between multiple resonant units in the coupled resonant array to converge the mass information of multiple substances to be measured onto the amplitude-frequency characteristic curve of a single high-frequency resonant unit 202, thereby achieving single-input single-output, synchronous, and high-precision identification and detection of multiple substances. By employing a simple frequency sweep excitation circuit to achieve multi-body resonance in the coupled array structure, the resonant frequency shifts of multiple resonant units caused by multiple substances are cleverly amplified and converged onto the amplitude-frequency characteristic curve of a single high-frequency resonant unit, greatly simplifying the output circuit and amplifying the sensitivity, thus achieving low-power, low-cost, and high-precision simultaneous identification and detection of multiple substances.

[0004] A coupled array sensor for simultaneous identification and detection of multiple trace substances includes a micro-actuator 1, a coupled resonant array 2, a specific adsorption film 3, a micro-transducer 4, and a base 5. The coupled resonant array 2 includes a high-frequency resonant unit 202, a low-frequency resonant unit 201, and a coupling unit 203. The micro-actuator 1 is fixed to the bottom of the base 5. Multiple low-frequency resonant units 201 are provided on the top of the base 5. A high-frequency resonant unit 202 is provided on the base 5 at the right end of the low-frequency resonant unit 201. A specific adsorption film 3 is deposited on the right end of each low-frequency resonant unit 201 and at both ends of the high-frequency resonant unit 202. The micro-transducer 4 is fixed to the front end surface of the high-frequency resonant unit 202. A part of the coupling unit 203 is fixed to the upper surface of the right end of the low-frequency resonant unit 201, and another part is fixed to the upper surface of the right side of the high-frequency resonant unit 202.

[0005] The high-frequency resonant unit 202 includes a transverse cantilever and a longitudinal cantilever, wherein the two transverse cantilever are arranged in parallel, and the right ends of the two transverse cantilever are respectively fixed to the front and rear ends below the longitudinal cantilever.

[0006] The low-frequency resonant unit 201 is a rectangular cantilever beam.

[0007] The coupling unit 203 is a magnetic coupling unit composed of cubic NdFeB magnets 20301 and cuboid NdFeB magnets 20302 with the same polarity facing each other. The cubic NdFeB magnets 20301 and cuboid NdFeB magnets 20302 are respectively fixed on the upper surface of the right end of the low-frequency resonant unit 201 and the upper surface of the longitudinal cantilever of the high-frequency resonant unit 202.

[0008] The micro actuator 1 is a piezoelectric actuator, electrostatic actuator, electromagnetic actuator, thermal actuator, optical actuator, shape memory alloy actuator, or magnetostrictive actuator.

[0009] In the coupled resonant array 2, the natural frequency ω of the low-frequency resonant unit 201 i (i=1, 2, 3…,n-1) are similar and increase approximately arithmetically, i.e., ω i - ω i-1 ≈ δ (i=1, 2, 3…,n-1), where n-1 is the number of low-frequency resonant units 201, n is the number of substances to be tested, which is also the sum of the number of n-1 low-frequency resonant units 201 and one high-frequency resonant unit 202; δ is the natural frequency difference between adjacent low-frequency resonant units 201; the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201 are approximately in an integer ratio, i.e., ω n ≈ αω1≈ αω2≈ … ≈ αω n-1 Where α is an integer, is the ratio of the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201, and ω nThe natural frequencies of the high-frequency resonant unit 202 are ω1, ω2…ω n-1 These are the natural frequencies of the n-1 low-frequency resonant units 201, respectively.

[0010] The number of low-frequency resonant units 201 in the coupled resonant array 2 is one less than the number of substances to be tested.

[0011] The coupling unit 203 is an electrostatic coupling unit, consisting of a main electrode plate and a secondary electrode plate. The main electrode plate 20301 and the secondary electrode plate 20302 are respectively fixed on the left end surface of the low-frequency resonant unit 201 and the right end surface of the high-frequency resonant unit 202, forming a parallel capacitor structure.

[0012] The specific adsorption film 3 is adsorbed onto the low-frequency resonant unit 201 and the high-frequency resonant unit 202 according to the properties of the analyte using the principles of bioadsorption, chemical adsorption or physical adsorption.

[0013] The micro-transducer 4 is a piezoelectric micro-transducer, including an upper electrode 401, a piezoelectric layer 402 and a lower electrode 403, wherein the lower electrode 403 is fixed on the transverse cantilever of the high-frequency resonant unit 202, the piezoelectric layer 402 is fixed on the lower electrode 403, and the upper electrode 401 is fixed on the piezoelectric layer 402.

[0014] A method for using a coupled array sensor for simultaneous identification and detection of multiple trace substances, as described above, includes the following steps:

[0015] Step 1: Calibrate the initial resonant frequency of each resonant unit:

[0016] At the natural frequency ω of the low-frequency resonant unit 201 i In the vicinity of (i=1, 2, 3…, n-1), a micro-actuator 1 is used with an amplitude of a. d The sensor is driven by an acceleration upsampling scan with an angular frequency of Ω. The low-frequency resonant unit 201 resonates under the upsampling scan drive of the micro-actuator 1. Due to the influence of its own cubic stiffness, the resonance peak of the low-frequency resonant unit 201 deviates from its natural frequency ω. i It deflects to the right and at the new frequency point ω i,1 Amplitude jump occurs:

[0017]

[0018] in , , m i k i c i k non,iThese are the effective mass, linear stiffness, linear damping, and cubic stiffness of the low-frequency resonant unit 201, respectively, and λ. i It is a nonlinear coupling force F c,i The linear term coefficients; in the nonlinear coupling force F c,i Under the influence of the micro-actuator 1, the high-frequency resonant unit 202 and the low-frequency resonant unit 201 resonate internally. Some of the vibration energy of the low-frequency resonant unit 201 is transferred to the high-frequency resonant unit 202, causing the high-frequency resonant unit 202 to resonate with its harmonic frequencies. When the driving frequency of the micro-actuator 1 is scanned to the natural frequency ω of the high-frequency resonant unit 202... n At 1 / α, that is At that time, the high-frequency resonant unit 202 exhibits a resonance peak, where m n k n These are the effective mass and linear stiffness of the high-frequency resonant unit 202, respectively; α is the approximate ratio of the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201; as the scanning drive frequency of the micro-actuator 1 continues to increase, the vibration amplitude of the low-frequency resonant unit 201 successively reaches its own jump frequency point ω. i,1 The downward jump causes the vibration energy transferred to the high-frequency resonant unit 202 to decrease in a stepwise manner, and therefore the vibration amplitude of the high-frequency resonant unit 202 also jumps downward in a stepwise manner.

[0019] The continuous voltage signal of the output micro-transducer 4 is obtained by Fourier transforming it to realize the natural frequency ω of the high-frequency resonant unit 202 at the resonance peak. n and the initial frequency ω at (n-1) amplitude jump points i,2 The calibration of (i=1, 2, 3…, n);

[0020] Step two: Install the sensor in the environment where the substance to be tested is located;

[0021] Step 3, with an amplitude of a d An acceleration with an angular frequency of Ω at 0.9ω 1,1 up to 1.5ω 1,1 The frequency range is cyclically increased to scan the micro-driver 1 and output the output voltage of the micro-transducer 4. During the frequency increase process, the frequency ω at the resonance peak of the high-frequency resonant unit 202 is obtained by Fourier transform at intervals of 0.0001ω1. n ´ and amplitude jump point frequency ω i,2 If the frequency ω at the resonance peak n The continuous change indicates that the specific adsorption film 3 on the high-frequency resonant unit 202 is continuously adsorbing the analyte. If the frequency ω at a certain amplitude jump point... i,2 The continuous change indicates that the specific adsorption film 3 on a certain low-frequency resonant unit 201 is continuously adsorbing the substance to be tested, until the frequency ω at the resonance peak of the high-frequency resonant unit 202 is reached. n´ and frequency ω at the amplitude jump point i,2 When the voltage remains stable, it indicates that adsorption equilibrium has been reached. At this point, the resonance peak frequency ω of the high-frequency resonant unit 202 after reaching adsorption equilibrium can be calculated based on the output voltage of the micro-transducer 4. n ´ and frequency ω at the amplitude jump point i,2 ´, and determine their relative initial values ​​ω respectively. n and ω i,2 Has an offset occurred?

[0022] Step 4, if the frequency ω at the resonance peak of the high-frequency resonant unit 202... n ´ relative to its initial value ω n The shift indicates that the specific adsorption film 3 on the high-frequency resonant unit 202 has adsorbed a substance to be tested; if the frequency ω at the i-th amplitude jump point of the high-frequency resonant unit 202... i,2 ´ relative to its initial value ω i,2 The shift indicates that the specific adsorption film 3 on the i-th low-frequency resonant unit 201 has adsorbed a substance. By statistically analyzing the frequency shift of the resonance peak and each amplitude jump point, the synchronous qualitative identification of n substances can be achieved.

[0023] Step 5: Based on the resonance peak and amplitude jump frequency ω measured before and after gas adsorption. n ´、ω n ω i,2 ´ and ω i,2 The actual adsorption amount of each substance is calculated according to the following formula, enabling the quantitative detection of multiple substances:

[0024]

[0025]

[0026] in: (i=1, 2, 3…, n) represents the mass of the adsorbed substance on the specific adsorption film 3 on the i-th low-frequency resonant unit 201. The mass of the adsorbed substance on the specific adsorption film 3 on the high-frequency resonant unit 202.

[0027] The beneficial effects of this invention are:

[0028] 1. By utilizing the frequency doubling effect of internal resonance, the sensitivity is amplified many times over.

[0029] 2. It utilizes amplitude jump points for sensing, resulting in ultra-high frequency resolution.

[0030] 3. It enables the simultaneous identification and detection of multiple trace substances.

[0031] 4. It achieves single-input single-output detection, simplifies the input and output circuits, reduces sensor power consumption, and reduces the amount of output data.

[0032] 5. It has the advantages of being tagless, high-precision, portable, low-cost, low-power, and fast-sensing. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the coupled array sensor structure of Embodiment 1 of the present invention;

[0034] Figure 2 This is a top view of the coupled array sensor of Embodiment 1 of the present invention;

[0035] Figure 3 This is a cross-sectional view of the coupled array sensor of Embodiment 1 of the present invention;

[0036] Figure 4 This is a schematic diagram of the microtransducer structure according to Embodiment 1 of the present invention;

[0037] Figure 5 This is a schematic diagram of the magnetic force and spatial relationship between the low-frequency resonant unit and the high-frequency resonant unit in Embodiment 1 of the present invention;

[0038] Figure 6 This is a magnetic field distribution diagram of Embodiment 1 of the present invention;

[0039] Figure 7 The diagram shows the first-order bending modes and modal frequencies of the low-frequency resonant unit and the high-frequency resonant unit in Embodiment 1 of the present invention.

[0040] Figure 8 The graph shows the dimensionless amplitude-frequency characteristic curves of the low-frequency resonant unit and the high-frequency resonant unit in Embodiment 1 of the present invention.

[0041] Figure 9 This is a schematic diagram of the coupled array sensor structure of Embodiment 2 of the present invention.

[0042] The components include: 1. Micro-actuator; 2. Coupled resonant array; 201. Low-frequency resonant unit; 202. High-frequency resonant unit; 203. Coupler unit; 203. 01. Cubic NdFeB magnet; 203. 02. Cuboid NdFeB magnet; 3. Specific adsorption film; 4. Micro-transducer; 401. Upper electrode; 402. Piezoelectric layer; 403. Lower electrode; 5. Base. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings; it should be understood that the preferred embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1As shown, a coupled array sensor for simultaneous identification and detection of multiple trace substances includes a micro-actuator 1, a coupled resonant array 2, a specific adsorption film 3, a micro-transducer 4, and a base 5. The coupled resonant array 2 further includes a high-frequency resonant unit 202, multiple low-frequency resonant units 201, and a coupling unit 203. The coupling unit 203 connects the low-frequency resonant units 201 and the high-frequency resonant units 202 to form a coupled array, constituting a multi-body resonance system. The micro-actuator 1 is fixed below the bottom of the base 5 and drives the entire sensor by frequency sweeping; the fixed end of the coupled resonant array 2 is connected to the top of the base 5; different specific adsorption films 3 are deposited on the free ends of each low-frequency resonant unit 201 and high-frequency resonant unit 202 of the coupled resonant array 2. The micro-transducer 4 is a piezoelectric transducer, fixed to the upper surface of the high-frequency resonant unit 202, used to convert vibration signals into voltage signals for output.

[0046] The coupled resonant array 2 includes a high-frequency resonant unit 202, multiple low-frequency resonant units 201, and a coupling unit 203. The coupling unit 203 connects the low-frequency resonant units 201 and the high-frequency resonant units 202 to form a coupled array, constituting a multi-body resonance system. The micro-actuator 1 is fixed to the bottom of the base 5. Multiple low-frequency resonant units 201 are provided on the top of the base 5. A high-frequency resonant unit 202 is provided on the top of the base 5 at the right end of the low-frequency resonant unit 201. Different specific adsorption films 3 are deposited on the right end of each low-frequency resonant unit 201 and at both ends of the high-frequency resonant unit 202. The micro-transducer 4 is fixed to the front end surface of the high-frequency resonant unit 202 and located at the front end of the low-frequency resonant unit 201. A part of the coupling unit 203 is fixed to the upper surface of the right end of the low-frequency resonant unit 201, close to the specific adsorption film 3 provided on the low-frequency resonant unit 201. The other part is fixed to the upper surface of the right side of the high-frequency resonant unit 202.

[0047] The specific adsorption films 3 deposited on the low-frequency resonant unit 201 and the high-frequency resonant unit 202 are films that specifically adsorb different gases. Their types are not limited. They can be films based on chemical reactions or films based on physical adsorption. The specific type should be selected according to the characteristics of the gas to be measured.

[0048] like Figure 2 The coupled resonant array 2 shown is a magnetically coupled cantilever beam array. The low-frequency resonant unit 201 is a rectangular cantilever beam, which is arranged at equal intervals to form a rectangular cantilever beam array; the high-frequency resonant unit 202 is a Π-shaped cantilever beam, which includes a transverse cantilever and a longitudinal cantilever. The two transverse cantilevers are arranged in parallel, and the right ends of the two transverse cantilevers are fixed to the front and rear ends below the longitudinal cantilever, respectively, and are located outside the rectangular cantilever beam array.

[0049] The micro actuator 1 is a piezoelectric actuator, electrostatic actuator, electromagnetic actuator, thermal actuator, optical actuator, shape memory alloy (SMA) actuator, or magnetostrictive actuator.

[0050] The coupling unit 203 is a magnetic coupling unit composed of cubic NdFeB magnets 20301 and cuboid NdFeB magnets 20302 with the same polarity facing each other. The cubic NdFeB magnets 20301 and cuboid NdFeB magnets 20302 are respectively fixed to the upper surface of the right end of the low-frequency resonant unit 201 and the upper surface of the longitudinal cantilever of the high-frequency resonant unit 202. This allows the low-frequency resonant unit 201 and the high-frequency resonant unit 202 to achieve vibration coupling through the repulsive force between the magnets.

[0051] The lengths of the low-frequency resonant units 201 are similar and increase approximately at equal arithmetic progressions, ensuring that the first-order bending mode frequencies of the low-frequency resonant units 201 also increase approximately at equal arithmetic progressions. The natural frequency ω of the low-frequency resonant units 201... i (i=1, 2, 3…, n-1) are similar and increase approximately arithmetically, i.e., ω i - ω i-1 ≈ δ (i=1, 2, 3…, n-1), where n-1 is the number of low-frequency resonant units 201, n is the number of substances to be tested, which is also the sum of the number of n-1 low-frequency resonant units 201 and one high-frequency resonant unit 202; δ is the natural frequency difference between adjacent low-frequency resonant units 201; the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201 are approximately in an integer ratio, i.e., ω n ≈ αω1≈ αω2≈ … ≈ αω n-1 Where α is an integer, representing the ratio of the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201, and ω... n The natural frequencies of the high-frequency resonant unit 202 are ω1, ω2…ω n-1 These are the natural frequencies of the n-1 low-frequency resonant units 201. The natural frequency ratio α is determined by the power of the inherent nonlinearity of the low-frequency resonant unit 201, the high-frequency resonant unit 202, and the coupling unit 203. The ratio of the first-order bending mode frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201 is 3, ω n ≈ 3ω1≈ 3ω2≈ … ≈ 3ω n-1 .

[0052] The number of low-frequency resonant units 201 in the coupled resonant array 2 is one less than the number of substances to be tested.

[0053] That is, the number of low-frequency resonant units 201 in the coupled resonant array 2 is determined by the amount of the substance to be tested. (n-1) low-frequency resonant units 201 and one high-frequency resonant unit 202 can realize the synchronous identification and detection of n substances.

[0054] The low-frequency resonant unit 201 and the high-frequency resonant unit 202 are collectively referred to as resonant units, and can adopt various micro-resonant structures such as resonant beams, resonant disks, resonant cavities, and resonant thin films.

[0055] like Figure 3 As shown, the low-frequency resonant unit 201, the high-frequency resonant unit 202, and the base 5 are fabricated from the same single-crystal silicon substrate using micro-nano fabrication technology. The base 5 has a centrally recessed opening structure.

[0056] The specific adsorption film 3 adsorbs the analyte onto the low-frequency resonant unit 201 and the high-frequency resonant unit 202 according to the specific adsorption principle of bioadsorption, chemical adsorption or physical adsorption based on the properties of the analyte.

[0057] like Figure 4 As shown, the micro-transducer 4 is a piezoelectric micro-transducer, including an upper electrode 401, a piezoelectric layer 402, and a lower electrode 403. The lower electrode 403 is fixed to the lateral cantilevered fixed end of the high-frequency resonant unit 202, the piezoelectric layer 402 is fixed to the lower electrode 403, and the upper electrode 401 is fixed to the piezoelectric layer 402. The upper electrode 401 and the lower electrode 403 are generally gold or platinum electrodes; the piezoelectric layer 402 can be made of PVDF piezoelectric thin film material or PZT ceramic material, etc.

[0058] The micro-transducer 4 can be based on other principles such as piezoresistive, capacitive, photoelectric, tunnel magnetoresistive, etc., to convert the vibration signal of the high-frequency resonant unit 202 into a voltage signal.

[0059] The micro-actuator 1 is a piezoelectric actuator, but other driving methods such as electrostatic driving, electromagnetic driving, thermal driving, optical driving, shape memory alloy (SMA) driving, and magnetostrictive driving can also be used.

[0060] The number of low-frequency resonant units 201 in the coupled resonant array 2 is determined by the amount of the substance to be tested. (n-1) low-frequency resonant units 201 and one high-frequency resonant unit 202 can realize the synchronous identification and detection of n substances.

[0061] The low-frequency resonant unit 201 and the high-frequency resonant unit 202 can also adopt various micro-resonant structures such as resonant disks, resonant cavities, and resonant thin films.

[0062] The coupling unit 203 can also adopt various coupling forms such as mechanical coupling, electrostatic coupling, optical coupling, and circuit coupling.

[0063] The low-frequency resonant unit 201, the high-frequency resonant unit 202, and the base 5 are an integrated structure, which are fabricated from the same single-crystal silicon substrate using micro-nano manufacturing technology.

[0064] A method for using the aforementioned coupled array sensor for simultaneous identification and detection of multiple trace substances includes the following steps:

[0065] Step 1: Calibrate the initial resonant frequency of each resonant unit of this sensor:

[0066] At the natural frequency ω of the low-frequency resonant unit 201 i In the vicinity of (i=1, 2, 3…, n-1), micro-driver 1 is used with the expression a d The acceleration of cos(Ωt) drives the entire sensor through frequency upsampling, and the motion equation of the coupled resonant array 2 can be expressed as:

[0067]

[0068]

[0069] Where, m i k i c i k non,i F c,i (i=1, 2, 3…, n-1) represent the effective mass, linear stiffness, linear damping, and cubic stiffness of the low-frequency resonant unit 201, respectively, and the nonlinear coupling force between the low-frequency resonant unit 201 and the high-frequency resonant unit 202; m n k n c n k nonn These are the effective mass, linear stiffness, linear damping, and cubic stiffness of the high-frequency resonant unit 202, respectively; x i (i=1, 2, 3…, n-1) represents the displacement of the i-th low-frequency resonant unit 201, x n t represents the displacement of the high-frequency resonant unit 202; t represents time.

[0070] n represents the quantity of the substance to be measured, which is also the sum of the number of n-1 low-frequency resonant units 201 and one high-frequency resonant unit 202; the nonlinear coupling force F c,i The power of F is approximately equal to the ratio α of the natural frequencies of the high-frequency resonant unit 202 and the low-frequency resonant unit 201, and is expressed as F. c,i = λ i (x i -x n )+χ i (x i -x n ) α , where λ i and χ i These are the nonlinear coupling forces F c,i The coefficients of the linear term and the coefficients of the nonlinear term;

[0071] Nonlinear coupling force F c,i F cc,i These are the repulsive force vectors between magnets, F. mag The vertical and horizontal components, vector F mag The expression is:

[0072]

[0073] Where µ0 is the space permeability, M i M n r is the magnetic moment; i It is the spatial vector between magnets. and r i These are their unit vector and scalar forms, respectively. The spatial relationships and magnetic effects of the coupled resonant array 2 are as follows: Figure 5 , 6 As shown, simplifying the above equation and discarding nonlinear terms of degree three or higher, we can obtain the expression for the nonlinear coupling force as follows:

[0074]

[0075] in,

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] Among them, L i V i These are the length of the i-th rectangular cantilever beam, i.e., the low-frequency resonant unit 201, and the volume of the cube neodymium iron boron magnet 20301 placed at its free end, respectively; L n V n These are the length of the Π-shaped cantilever beam, i.e., the high-frequency resonant unit 202, and the volume of the cuboid neodymium iron boron magnet 20302 placed at its free end; d i It is the initial center distance between the cubic NdFeB magnet 20301 and the cuboid NdFeB magnet 20302.

[0083] The low-frequency resonant unit 201 resonates under the up-frequency scanning drive of the micro-actuator 1. The first-order bending modes and mode frequencies of the low-frequency resonant unit 201 and the high-frequency resonant unit 202 are as follows: Figure 7 As shown. Due to the influence of its own cubic stiffness, the resonance peak of the low-frequency resonant unit 201 deviates from its natural frequency ω. i It deflects to the right and at the new frequency point ω i,1 An amplitude jump occurs, such as Figure 8 As shown:

[0084]

[0085] in , , The magnetic field distribution of the sensor is as follows: Figure 6 As shown, under the nonlinear coupling force F c,i Under the influence of the low-frequency resonant unit 201, during vibration, the cuboid NdFeB magnet 20301 at its free end generates a circulating magnetic field, which acts on the high-frequency resonant unit 202 through the cuboid NdFeB magnet 20302, causing internal resonance between the high-frequency resonant unit 202 and the low-frequency resonant unit 201. Part of the vibrational energy of the low-frequency resonant unit 201 is thus transferred to the high-frequency resonant unit 202, causing harmonic resonance in the high-frequency resonant unit 202. Since the vibration of the high-frequency resonant unit 202 is relatively small, the effect of cubic stiffness on the resonance peak can be ignored. Therefore, when the micro-actuator 1 drives the frequency to the natural frequency ω of the high-frequency resonant unit 202... n 1 / 3 of the way ( When a=3, the high-frequency resonant unit 202 exhibits a resonance peak, the frequency of which is the initial frequency ω at which the high-frequency resonant unit 202 exhibits a resonance peak. n As the scanning drive frequency of micro-actuator 1 continues to increase, the vibration amplitude of low-frequency resonant unit 201 successively reaches its own jump frequency point ω. i,1 The downward jump causes the vibrational energy transferred to the high-frequency resonant unit 202 to decrease in a stepwise manner, thus the vibrational amplitude of the high-frequency resonant unit 202 also jumps downward in a stepwise manner. Therefore, a resonance peak and (n-1) amplitude jump points ω can be observed on the amplitude-frequency curve of the high-frequency resonant unit 202. i,2 Among them, the i-th amplitude jump point ω of the high-frequency resonant unit 202 i,2 The amplitude jump point ω corresponding to the i-th low-frequency resonant unit 201 i,1 And the vibration frequency α is amplified by 3 times, that is:

[0086]

[0087] The continuous voltage signal of the output micro-transducer 4 is obtained by fast Fourier transform and frequency information is obtained to realize the initial frequency, i.e., the natural frequency ω, of the high-frequency resonant unit 202 at the resonance peak. n and (n-1) initial frequencies ω at amplitude jump points i,2 The calibration.

[0088] Step two: Install the sensor in the environment where the substance to be tested is located;

[0089] Step 3, with an amplitude of a d An acceleration with an angular frequency of Ω at 0.9ω 1,1 up to 1.5ω 1,1 The frequency range is cyclically increased to scan the micro-driver 1 and output the output voltage of the micro-transducer 4. During the frequency increase process, the frequency ω at the resonance peak of the high-frequency resonant unit 202 is obtained by Fourier transform at intervals of 0.0001ω1. n ´ and amplitude jump point frequency ω i,2 If the frequency ω at the resonance peak n The continuous change indicates that the specific adsorption film 3 on the high-frequency resonant unit 202 is continuously adsorbing the analyte. If the frequency ω at a certain amplitude jump point... i,2 The continuous change indicates that the specific adsorption film 3 on a certain low-frequency resonant unit 201 is continuously adsorbing the substance to be tested, until the frequency ω at the resonance peak of the high-frequency resonant unit 202 is reached. n ´ and frequency ω at the amplitude jump point i,2 When the voltage remains stable, it indicates that adsorption equilibrium has been reached. At this point, the resonance peak frequency ω of the high-frequency resonant unit 202 after reaching adsorption equilibrium can be calculated based on the output voltage of the micro-transducer 4. n ´ and frequency ω at the amplitude jump point i,2 ´, and determine their relative initial values ​​ω respectively. n and ω i,2 Whether a shift has occurred; the amplitude is largest at the resonance peak, and the position of the resonance peak of the high-frequency resonant unit 202 is determined by detecting the maximum amplitude during the frequency sweep process;

[0090] Step 4, if the frequency ω at the resonance peak of the high-frequency resonant unit 202... n ´ relative to its initial value ω n The shift indicates that the specific adsorption film 3 on the high-frequency resonant unit 202 has adsorbed a substance to be tested; if the frequency ω at the i-th amplitude jump point of the high-frequency resonant unit 202... i,2 ´ relative to its initial value ω i,2 The shift indicates that the specific adsorption film 3 on the i-th low-frequency resonant unit 201 has adsorbed a substance. By statistically analyzing the frequency shift of the resonance peak and each amplitude jump point, the synchronous qualitative identification of n substances can be achieved.

[0091] Step 5: Based on the resonance peak and amplitude jump frequency ω measured before and after gas adsorption. n ´、ω n ω i,2 ´ and ω i,2The actual adsorption amount of each substance is calculated according to the following formula, enabling the quantitative detection of multiple substances:

[0092]

[0093]

[0094] in: (i=1, 2, 3…, n) represents the mass of the adsorbed substance on the specific adsorption film 3 on the i-th low-frequency resonant unit 201. The mass of the adsorbed substance on the specific adsorption film 3 on the high-frequency resonant unit 202.

[0095] Example 2

[0096] like Figure 9 As shown, it is the same as in Embodiment 1, except that the relative positions of the fixed ends of the high-frequency resonant unit 202 and the low-frequency resonant unit 201 have changed; the high-frequency resonant unit 202 and the low-frequency resonant unit 201 have changed from being fixed on the same side to being fixed on opposite sides, and are fixed on the upper surface of the opposite side wall of the base.

[0097] Example 2

[0098] Similar to Embodiment 1, the difference is that the coupling unit 203 is a mechanical coupling unit, which is integrally processed with the low-frequency resonant unit 201 and the high-frequency resonant unit 202 and fixed to the top of the base 5. Coupling units 203 are provided between adjacent low-frequency resonant units 201, and coupling units 203 are provided between the foremost low-frequency resonant unit 201 and the high-frequency resonant unit 202, as well as between the rearmost low-frequency resonant unit 201 and the high-frequency resonant unit 202.

[0099] Example 3

[0100] Similar to Embodiment 1, the difference is that the coupling unit 203 is an electrostatic coupling unit, which consists of a main electrode plate and a secondary electrode plate. The main electrode plate 20301 and the secondary electrode plate 20302 are respectively fixed on the left end surface of the low-frequency resonant unit 201 and the right end surface of the high-frequency resonant unit 202, forming a parallel capacitor structure.

[0101] The microtransducer 4 is a piezoresistive microtransducer, which consists of a constant voltage source, a metal piezoresistive strain gauge, a positive electrode, and a negative electrode. The metal piezoresistive strain gauge is attached to the lateral cantilever surface of the high-frequency resonant unit, and its two ends are respectively provided with a positive electrode and a negative electrode. The positive electrode and the negative electrode are connected to the constant voltage source to form a circuit loop, which can detect the end voltage of the metal piezoresistive strain gauge.

[0102] Example 4

[0103] Similar to Embodiment 1, the difference is that the micro-transducer 4 is a capacitive micro-transducer, which is a circuit loop composed of an oscillation circuit, a sensing capacitor, a fixed capacitor, and a detection circuit; wherein, the sensing capacitor is a displacement-type parallel capacitor transducer structure composed of a movable electrode plate fixed on the longitudinal cantilever surface of the high-frequency resonant unit and a fixed electrode plate fixed on the base surface; the detection circuit can be a bridge circuit or an operational amplifier circuit.

[0104] Example 5

[0105] Similar to Embodiment 1, the difference is that the micro-transducer 4 is a photoelectric micro-transducer, which consists of a transmitter, a receiver and a detection circuit, wherein the transmitter is aligned with the longitudinal cantilever geometric center of the high-frequency resonant unit.

Claims

1. A coupled array sensor for simultaneous identification and detection of multiple trace substances, characterized in that... The device includes a micro-actuator (1), a coupled resonant array (2), a specific adsorption film (3), a micro-transducer (4), and a base (5). The coupled resonant array (2) includes a high-frequency resonant unit (202), a low-frequency resonant unit (201), and a coupling unit (203). The micro-actuator (1) is fixed at the bottom of the base (5). Multiple low-frequency resonant units (201) are provided on the top of the base (5). A high-frequency resonant unit (202) is provided on the base (5) at the right end of the low-frequency resonant unit (201). A specific adsorption film (3) is deposited on the right end of each low-frequency resonant unit (201) and at both ends of the high-frequency resonant unit (202). The micro-transducer (4) is fixed on the front end surface of the high-frequency resonant unit (202). A part of the coupling unit (203) is fixed on the upper surface of the right end of the low-frequency resonant unit (201), and another part is fixed on the upper surface of the right side of the high-frequency resonant unit (202). The low-frequency resonant unit (201) is a rectangular cantilever beam; The high-frequency resonant unit (202) includes a transverse cantilever and a longitudinal cantilever, wherein the two transverse cantilever are arranged in parallel, and the right ends of the two transverse cantilever are respectively fixed to the front and rear ends below the longitudinal cantilever. In the coupled resonant array (2), the natural frequency ω of the low-frequency resonant unit (201) i The numbers increase in an approximately arithmetic progression, i.e., ω i - ω i-1 ≈ δ, i=1, 2, 3…, n-1, where n-1 is the number of low-frequency resonant units (201), n ​​is the number of substances to be tested, which is also the sum of the number of n-1 low-frequency resonant units (201) and one high-frequency resonant unit (202); δ is the natural frequency difference between adjacent low-frequency resonant units (201); the natural frequencies of the high-frequency resonant unit (202) and the low-frequency resonant unit (201) are approximately in an integer ratio, i.e., ω n ≈ αω1≈ αω2≈ … ≈ αω n-1 Where α is an integer, is the ratio of the natural frequencies of the high-frequency resonant unit (202) and the low-frequency resonant unit (201), and ω n Let ω1, ω2…ω be the natural frequencies of the high-frequency resonant unit (202). n-1 These are the natural frequencies of the n-1 low-frequency resonant units (201).

2. The coupled array sensor for simultaneous identification and detection of multiple trace substances according to claim 1, characterized in that... The coupling unit (203) is a magnetic coupling unit composed of cubic neodymium iron boron magnets (20301) and cuboid neodymium iron boron magnets (20302) with the same polarity facing each other. The cubic neodymium iron boron magnets (20301) and cuboid neodymium iron boron magnets (20302) are respectively fixed on the upper surface of the right end of the low-frequency resonant unit (201) and the upper surface of the longitudinal cantilever of the high-frequency resonant unit (202).

3. The coupled array sensor for simultaneous identification and detection of multiple trace substances according to claim 1, characterized in that... The micro actuator (1) is a piezoelectric actuator, electrostatic actuator, electromagnetic actuator, thermal actuator, optical actuator, shape memory alloy actuator or magnetostrictive actuator.

4. A coupled array sensor for simultaneous identification and detection of multiple trace substances according to claim 1, characterized in that... The number of low-frequency resonant units (201) in the coupled resonant array (2) is one less than the number of substances to be tested.

5. A coupled array sensor for simultaneous identification and detection of multiple trace substances according to claim 1, characterized in that... The specific adsorption film (3) is adsorbed onto the low-frequency resonant unit (201) and the high-frequency resonant unit (202) according to the properties of the substance to be tested using the principles of bioadsorption, chemical adsorption or physical adsorption.

6. A coupled array sensor for simultaneous identification and detection of multiple trace substances according to claim 1, characterized in that... The micro-transducer (4) is a piezoelectric micro-transducer, including an upper electrode (401), a piezoelectric layer (402) and a lower electrode (403), wherein the lower electrode (403) is fixed on the transverse cantilever of the high-frequency resonant unit (202), the piezoelectric layer (402) is fixed on the lower electrode (403), and the upper electrode (401) is fixed on the piezoelectric layer (402).

7. A method for using a coupled array sensor for simultaneous identification and detection of multiple trace substances as described in claim 1, comprising the following steps: Step 1: Calibrate the initial resonant frequency of each resonant element: At the natural frequency ω of the low-frequency resonant unit (201) i For i=1, 2, 3…, n-1, use a micro-actuator (1) with an amplitude of a d The sensor is driven by an acceleration upsampling scan with an angular frequency of Ω. The low-frequency resonant unit (201) resonates under the upsampling scan drive of the micro-actuator (1). Due to the influence of its own cubic stiffness, the resonance peak of the low-frequency resonant unit (201) deviates from its own natural frequency ω. i It deflects to the right and at the new frequency point ω i,1 Amplitude jump occurs: i=1, 2, 3…,n-1 in , , m i k i c i k non,i These are the effective mass, linear stiffness, linear damping, and cubic stiffness of the low-frequency resonant unit (201), respectively, and λ. i It is a nonlinear coupling force F c,i The linear term coefficients; in the nonlinear coupling force F c,i Under the influence of the micro-actuator (1), the high-frequency resonant unit (202) and the low-frequency resonant unit (201) resonate internally. Some of the vibration energy of the low-frequency resonant unit (201) is transferred to the high-frequency resonant unit (202), causing the high-frequency resonant unit (202) to resonate at its harmonic frequency. When the driving frequency of the micro-actuator (1) is scanned to the natural frequency ω of the high-frequency resonant unit (202), n At 1 / α, that is At that time, the high-frequency resonant unit (202) exhibits a resonance peak, where m n k n These are the effective mass and linear stiffness of the high-frequency resonant unit (202), respectively. α is the approximate ratio of the natural frequencies of the high-frequency resonant unit (202) and the low-frequency resonant unit (201). As the scanning drive frequency of the micro-actuator (1) continues to increase, the vibration amplitude of the low-frequency resonant unit (201) successively reaches its own jump frequency point ω. i,1 The downward jump causes the vibration energy transferred to the high-frequency resonant unit (202) to decrease in a stepwise manner, and therefore the vibration amplitude of the high-frequency resonant unit (202) also jumps downward in a stepwise manner. The continuous voltage signal of the output micro-transducer (4) is obtained by Fourier transform and the frequency information is obtained to realize the natural frequency ω of the high-frequency resonant unit (202) at the resonance peak. n and the initial frequency ω at n-1 amplitude jump points i,2 The calibration of i = 1, 2, 3, ..., n; Step two: Install the sensor in the environment where the substance to be tested is located; Step 3, with an amplitude of a d An acceleration with an angular frequency of Ω at 0.9ω 1,1 up to 1.5ω 1,1 The micro-driver (1) is cyclically up-scanned within the frequency range and the output voltage of the micro-transducer (4) is output. During the up-scanning process, the frequency ω at the resonance peak of the high-frequency resonant unit (202) is continuously obtained by Fourier transform at intervals of 0.0001ω1. n ´ and amplitude jump point frequency ω i,2 ´; If the frequency ω at the resonance peak n The continuous change indicates that the specific adsorption film (3) on the high-frequency resonant unit (202) is continuously adsorbing the substance to be tested. If the frequency ω of a certain amplitude jump point is... i,2 The continuous change indicates that the specific adsorption film (3) on a certain low-frequency resonant unit (201) is continuously adsorbing the substance to be tested, until the frequency ω at the resonance peak of the high-frequency resonant unit (202) is reached. n ´ and frequency ω at the amplitude jump point i,2 When the voltage remains stable, it indicates that adsorption equilibrium has been reached. At this point, the resonance peak frequency ω of the high-frequency resonant unit (202) after reaching adsorption equilibrium can be calculated based on the output voltage of the micro-transducer (4). n ´ and frequency ω at the amplitude jump point i,2 ´, and determine their relative initial values ​​ω respectively. n and ω i,2 Has an offset occurred? Step 4, if the frequency ω at the resonance peak of the high-frequency resonant unit (202) n ´ relative to its initial value ω n The shift indicates that the specific adsorption film (3) on the high-frequency resonant unit (202) has adsorbed a substance to be tested; if the frequency ω at the i-th amplitude jump point of the high-frequency resonant unit (202) is... i,2 ´ relative to its initial value ω i,2 The shift indicates that the specific adsorption film (3) on the i-th low-frequency resonant unit (201) has adsorbed a substance. The frequency shift of the resonance peak and each amplitude jump point is statistically analyzed to achieve synchronous qualitative identification of n substances. Step 5: Based on the resonance peak and amplitude jump frequency ω measured before and after gas adsorption. n ´、ω n ω i,2 ´ and ω i,2 The actual adsorption amount of each substance is calculated according to the following formula, enabling the quantitative detection of multiple substances: ； ； in: , i=1, 2, 3…, n is the mass of the adsorbed substance on the specific adsorption film (3) on the i-th low-frequency resonant unit (201), The mass of the adsorbed substance on the specific adsorption film (3) on the high-frequency resonant unit (202).

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