Hot wire type MEMS sensor testing device based on microscopic thermal imaging technology and measuring method thereof

Abstract

The invention relates to the technical field of sensor measurement and evaluation, in particular to a hot-wire type MEMS sensor testing device based on a microscopic thermal imaging technology and a measuring method thereof, and the device comprises an acoustic emission unit, an acoustic receiving unit and an MTIT thermal field monitoring unit which work in cooperation with one another. The acoustic emission unit is composed of a horizontal and vertical high-precision positioning support, an acoustic emitter, a power amplifier, an acoustic spectrometer and a full anechoic chamber, and is used for generating uniform sound fields with different frequencies. The sound receiving unit consists of a slidable clamp, a horizontal high-precision positioning long supporting rod, a standard vector microphone and a signal acquisition analyzer, and is used for receiving sound field information at a certain position in the full anechoic room; the MTIT thermal field monitoring part is composed of a slidable clamp, a horizontal high-precision positioning short supporting rod, a refrigeration focal plane detector and an infrared microscope objective, and is used for monitoring the real-time change of a thermal field of a thermal sensing module of the hot-wire type MEMS sensor, and the thermal field monitoring device can comprehensively evaluate the performance of the hot-wire type MEMS sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor measurement and evaluation, and specifically relates to a hot-wire MEMS sensor testing device based on microscopic thermal imaging technology and a measurement method thereof. Background Art

[0002] Vector sensors can simultaneously grasp the scalar and vector information of the sound field. They have unique advantages in capturing target direction and trajectory information, and are particularly suitable for working in low ocean background noise environments. They are of great significance for detecting low-observable targets such as submarines and unmanned platforms. The performance of hot-wire vector sensors based on microelectromechanical systems (MEMS) is better than other types of vector sensors in low-frequency detection, and the lowest test frequency of 5Hz can be achieved. However, there is still a significant gap between the actual engineering application and theoretical research of MEMS hot-wire sensors in China, especially in the research of underwater acoustic sensing detection in extremely low frequency and high water pressure environments. To fill this gap and improve performance, the key lies in the precise control of each link of the sensor and a comprehensive understanding of its thermodynamics, fluid mechanics and acoustic characteristics. At present, the test method is mainly based on the acoustic standing wave tube to evaluate the overall acoustic characteristics of the hot-wire vector sensor. It can only analyze the data processed by the electronic warehouse, but cannot quantitatively measure the key part of the sensor, the acoustic thermal convection, and evaluate its accuracy and stability. Therefore, a new device or technical method is developed to accurately measure and evaluate the distribution of thermal and flow fields in MEMS hot wire vector sensors, which can provide guidance for developing technologies for fine testing of local components of new MEMS hot wire vector sensors and help discover and solve key problems in the research and development stage. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a hot-wire MEMS sensor testing device and a measuring method based on microscopic thermal imaging technology, which are used to measure the temperature perception sensitivity of the hot-wire MEMS vector sensor, reflect the strength of the temperature change in the sensor within the measurement range, and analyze the thermal field output by the hot-wire MEMS sensor and the real thermal field output by MTIT, the flow field in the hot-wire MEMS sensor calculated based on the MEMS three-suspended hot wire model and the real flow field, and the flow field calculated by MTIT based on the MEMS three-suspended hot wire model and the real flow field, so as to provide refined data guidance for the development of hot-wire MEMS vector sensors.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a hot-wire MEMS sensor testing device based on microscopic thermal imaging technology, comprising an acoustic emission unit, an acoustic receiving unit and a MTIT thermal field monitoring unit working in cooperation with each other, wherein the acoustic emission unit is composed of a horizontal and vertical high-precision positioning bracket, an acoustic emitter, a power amplifier, a spectrometer and a full anechoic chamber, and is used to generate a uniform sound field of different frequencies; the acoustic receiving unit is composed of a slidable fixture, a horizontal high-precision positioning long support rod, a standard vector microphone and a signal acquisition analyzer, and is used to receive the sound field information at a certain position in the full anechoic chamber; the MTIT thermal field monitoring unit is composed of a slidable fixture, a horizontal high-precision positioning short support rod, a refrigerated focal plane detector and an infrared microscope objective lens, and is used to monitor the real-time changes of the thermal field of the thermal sensing module of the hot-wire MEMS sensor, and the acoustic emission unit, the acoustic receiving unit and the MTIT thermal field monitoring unit work in cooperation through a computer and peripherals.

[0005] To achieve the above object, the present invention also provides the following technical solution: a measurement method of a hot-wire MEMS sensor test device based on microscopic thermal imaging technology, according to the hot-wire MEMS sensor test device, the steps are:

[0006] Step 1: Determine the relevant physical information of the hot wire MEMS sensor, including the spacing between the hot wires, the type of liquid filled inside, and the thermal conductivity, specific heat capacity and density of the liquid;

[0007] Step 2: Build a horizontal and vertical high-precision positionable bracket, move the slidable fixture to the specified position, install the infrared microscope objective on the horizontal high-precision positioning short support rod, install the MEMS sensor to be tested and the standard vector microphone at the same height on the horizontal high-precision positioning long support rod, arrange the sound transmitter under the MEMS sensor to be tested and the standard vector microphone, and connect instruments including power amplifier, spectrometer, signal acquisition analyzer, refrigerated focal plane detector, computer and peripherals;

[0008] Step 3: Start the sound transmitter to form a stable sound field in the test area. The sound field shows horizontal uniformity, that is, the sound pressure at each point at the same height should be equal, and record the ambient temperature value;

[0009] Step 4: Use a standard vector microphone to obtain the sound field information in the test area and ensure that the sound field is in a stable state. At the same time, start the hot wire MEMS sensor, confirm the initial power value of the hot wire excitation, and record the real-time resistance temperature change value of the hot wire and the generated sound field information. In addition, start the infrared microscope objective lens to collect the internal temperature field distribution information of the hot wire MEMS sensor;

[0010] Step 5: Import the data into the post-processing program. The post-processing program module calculates the temperature field perception sensitivity through the formula, and analyzes the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, the flow field calculated based on the MEMS three-suspended hot wire model in the hot-wire MEMS sensor and the real flow field, and the flow field calculated based on the MEMS three-suspended hot wire model by the MTIT and the real flow field.

[0011] In some embodiments, the calculation formula in step 5 is:

[0012] M T-MTIT =T MTIT-center / p

[0013] T MTIT-matched-degree =T / T MTIT-center

[0014]

[0015] Where M T-MTIT is the temperature field perception sensitivity, T MTIT-center is the temperature at the central hot line position of the hot wire MEMS sensor thermal sensing module obtained by microthermal imaging technology, p is the sound pressure value collected by the standard vector microphone, T MTIT-matched-degree is the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, T is the temperature value of the central hot wire, c f is the specific heat capacity of the liquid filled in the hot-wire MEMS sensor, ρ f is the density of the liquid filled in the hot wire MEMS sensor, u sim-centre is the theoretical flow velocity near the central hot wire of the hot wire MEMS sensor thermal sensing module, Δh is the distance between two adjacent hot wires, Q is the heat source power of the hot wire MEMS sensor, k is the thermal conductivity of the liquid filled in the hot wire MEMS sensor, T 1 ,T 2 ,T 3 are the temperatures of the upper, middle and lower hot wires, u sim-MTIT-centre The flow rate is calculated by using the temperature value of the hot wire of the thermal sensing module of the hot wire MEMS sensor obtained by microthermal imaging technology, T 1-MTIT ,T 2-MTIT ,T 3-MTIT are the temperatures of the upper, middle and lower hot wires obtained using microthermal imaging technology, u MTIT-matched-degree The matching degree between the flow field estimated by MTIT based on the MEMS three-suspended hot wire model and the real flow field, u sim-matched-degree The matching degree between the flow field estimated based on the MEMS three suspended hot wire model and the real flow field in the hot wire MEMS sensor, u real The particle velocity is acquired by a standard vector microphone.

[0016] In some of the embodiments, in step 2, the measuring device should be arranged in a full anechoic chamber environment to reduce the impact of environmental noise on the test.

[0017] In some of the embodiments, in step 4, the hot-wire MEMS sensor, the standard vector microphone and the infrared microscope objective lens realize synchronous real-time acquisition.

[0018] In some of the embodiments, in step 5, based on a MEMS three-suspended hot wire model of steady-state heat transfer, a finite difference method is used to obtain flow field data near the central hot wire.

[0019] Compared with the prior art, the beneficial effect of the present invention is that the present invention is used to evaluate the effectiveness of sensor data measurement. The device includes an acoustic emission unit, an acoustic receiving unit and an MTIT thermal field monitoring unit that work together. Based on the finite difference method, the temperature field perception sensitivity is obtained through the relationship between temperature and sound pressure, and the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT are analyzed, and the flow field in the hot-wire MEMS sensor is calculated based on the MEMS three-suspended hot wire model and the real flow field, and the flow field calculated by the MTIT based on the MEMS three-suspended hot wire model and the real flow field match degree is analyzed to accurately measure and evaluate the distribution of thermal fields and flow fields in MEMS hot-wire vector sensors, which can provide guidance for the development of fine testing technology for local components of new MEMS hot-wire vector sensors, and help discover and solve key problems in the research and development stage.

[0020] The test device and measurement method provided by the present invention innovatively integrate acoustic and thermodynamic technologies, and can provide a method for comprehensively evaluating the performance of hot-wire MEMS sensors. The highlights of the device and method are stable acoustic and thermal field information collection, temperature field perception sensitivity calculation, and real-time monitoring and post-processing, which provides a new method with good effect for hot-wire MEMS sensor performance evaluation and is expected to promote research and development in this field.

[0021] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand. The present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the testing device of the present invention;

[0023] Figure 2 It is a flow chart of the measuring method of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1 The present invention provides a technical solution: a hot-wire MEMS sensor testing device based on microscopic thermal imaging technology, comprising an acoustic emission unit, an acoustic receiving unit and a MTIT thermal field monitoring unit that work in coordination with each other, wherein the acoustic emission unit is composed of a horizontal and vertical high-precision positioning bracket 1, an acoustic emitter 2, a power amplifier, a spectrometer and a full anechoic chamber, and is used to generate a uniform sound field of different frequencies; the acoustic receiving unit is composed of a slidable fixture, a horizontal high-precision positioning long support rod 7, a standard vector microphone 3 and a signal acquisition analyzer, and is used to receive the sound field information at a certain position in the full anechoic chamber; the MTIT thermal field monitoring unit is composed of a slidable fixture 8, a horizontal high-precision positioning short support rod 6, a refrigerated focal plane detector and an infrared microscope objective lens 5, and is used to monitor the real-time changes in the thermal field of a thermal sensing module of a hot-wire MEMS sensor 4, and the acoustic emission unit, the acoustic receiving unit and the MTIT thermal field monitoring unit work in coordination through a computer and peripherals.

[0026] See also Figure 1 The hot-wire MEMS sensor 4 to be tested should be left in the anechoic chamber for 1 hour to allow the internal temperature to be balanced with the ambient temperature. The hot-wire MEMS sensor 4 to be tested is installed in the anechoic chamber environment by means of a horizontal high-precision positioning long support rod 7, wherein the horizontal high-precision positioning long support rod 7 is made of a hollow thin carbon fiber rod with a diameter of 1 cm to reduce the influence of the support rod on the sound field, and a slidable clamp 8 is arranged at the front section of the rod.

[0027] The standard vector microphone 3 is installed at the same height as the hot-wire MEMS sensor 4 to be tested, and this height should be at least 2 to 3 times greater than the maximum dimension of the hot-wire MEMS sensor 4 to ensure the stability of the sound field. The standard vector microphone is used to measure the real particle velocity at the sensor installation height.

[0028] An infrared microscope objective lens 5 is installed on the left side of the hot-wire MEMS sensor 4 to be tested by using a horizontal high-precision positioning short support rod 6. The infrared microscope objective lens 5 is connected to a refrigerated focal plane detector and connected to a computer and peripherals through an IEEE488 bus to achieve synchronous temperature field data acquisition.

[0029] An acoustic transmitter 2 is arranged on the upper part of the horizontal and vertical high-precision positionable bracket 1, and the acoustic transmitter 2 is connected to a power amplifier and a spectrometer to generate sound waves of different frequencies.

[0030] The acquisition analyzer, the cooling focal plane detector, and the spectrometer are connected to the computer and peripherals via IEEE 488 connection lines to ensure that the standard vector microphone 3, the hot-wire MEMS sensor 4 to be tested, and the infrared microscope objective lens 5 realize synchronous data acquisition.

[0031] The measuring method of the hot-wire MEMS sensor testing device based on microscopic thermal imaging technology, according to the hot-wire MEMS sensor testing device, comprises the following steps:

[0032] Step 1: Determine the relevant physical information of the hot wire MEMS sensor 4, including the distance Δh between the hot wires, the type of the internal filling liquid, and the thermal conductivity k and specific heat capacity c of the liquid. f , density ρ f ;

[0033] Step 2: Build a horizontal and vertical high-precision positionable bracket 1, and move the slidable fixture 8 to the specified position, install the infrared microscope objective lens 5 on the horizontal high-precision positioning short support rod 6, and install the infrared microscope objective lens 5 on the horizontal high-precision positioning long support rod at the same height d 0 A MEMS sensor 4 to be tested and a standard vector microphone 3 are installed at the position, an acoustic transmitter 2 is arranged below the MEMS sensor 4 to be tested and the standard vector microphone 3, and instruments including a power amplifier, a sound spectrometer, a signal acquisition analyzer, a refrigerated focal plane detector, a computer and peripherals are connected;

[0034] Step 3: Start the sound transmitter 2 to form a stable sound field in the test area. The sound field shows horizontal uniformity, that is, the sound pressure at each point at the same height should be equal, and record the ambient temperature value;

[0035] Step 4: Use the standard vector microphone 3 to obtain the sound field information in the test area, and ensure that the sound field in the area of ​​action of the sound emitter 2 is in a stable state. At the same time, start the hot wire MEMS sensor 4, confirm the initial power value Q of the hot wire excitation, and record the real-time resistance (temperature) change value T of the hot wire. 1 , T 2 , T 3 In addition, the infrared microscope objective lens 5 is started to collect the real-time distribution information of the temperature field inside the hot wire MEMS sensor, and after determining that the temperature field distribution is stable, the hot wire temperature value T is extracted. 1-MTIT , T 2-MTIT , T 3-MTIT ;

[0036] Step 5: Import the data into the post-processing program. The post-processing program module calculates the temperature field perception sensitivity through the following formula, and analyzes the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, the flow field in the hot-wire MEMS sensor based on the MEMS three-suspended hot-wire model and the real flow field, and the flow field in the MTIT based on the MEMS three-suspended hot-wire model and the real flow field:

[0037] M T-MTIT =T MTIT-center / p

[0038] T MTIT-matched-degree =T / T MTIT-center

[0039]

[0040] Where M T-MTIT is the temperature field perception sensitivity, T MTIT-center is the temperature at the central hot line position of the hot wire MEMS sensor thermal sensing module obtained by microthermal imaging technology, p is the sound pressure value collected by the standard vector microphone, T MTIT-matched-degree is the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, T is the temperature value of the central hot wire, c f is the specific heat capacity of the liquid filled in the hot-wire MEMS sensor, ρ f is the density of the liquid filled in the hot wire MEMS sensor, u sim-centre is the theoretical flow velocity near the central hot wire of the hot wire MEMS sensor thermal sensing module, Δh is the distance between two adjacent hot wires, Q is the heat source power of the hot wire MEMS sensor, k is the thermal conductivity of the liquid filled in the hot wire MEMS sensor, T 1 ,T 2 ,T 3 are the temperatures of the upper, middle and lower hot wires, u sim-MTIT-centre The flow rate is calculated by using the temperature value of the hot wire of the thermal sensing module of the hot wire MEMS sensor obtained by microthermal imaging technology, T 1-MTIT ,T 2-MTIT ,T 3-MTIT are the temperatures of the upper, middle and lower hot wires obtained using microthermal imaging technology, u MTIT-matched-degree The matching degree between the flow field estimated by MTIT based on the MEMS three-suspended hot wire model and the real flow field, u sim-matched-degree The matching degree between the flow field estimated based on the MEMS three suspended hot wire model and the real flow field in the hot wire MEMS sensor, u real The particle velocity is acquired by a standard vector microphone.

[0041] In step 2, the measurement device should be placed in a fully anechoic chamber environment to reduce the impact of environmental noise on the test.

[0042] In step 4, the hot-wire MEMS sensor, standard vector microphone and infrared microscope objective lens realize synchronous real-time acquisition.

[0043] In step five, based on the MEMS three-suspended hot wire model of steady-state heat transfer, the finite difference method is used to obtain the flow field data near the central hot wire.

[0044] This technical solution can provide accurate data for the development of hot-wire MEMS sensors and evaluate their performance, especially for the fields of ultra-low ocean noise environment research, high-stealth submarines and unmanned platform positioning. The invention fills the technical gap in this field and provides important tools and data support for scientific research and engineering applications.

[0045] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hot-wire MEMS sensor testing device based on micro-thermal imaging technology, Features: It includes an acoustic emission unit, an acoustic receiving unit and an MTIT thermal field monitoring unit that work in coordination with each other. The acoustic emission unit is composed of a horizontal and vertical high-precision positioning bracket, an acoustic transmitter, a power amplifier, a spectrometer and a full anechoic chamber to generate a uniform sound field of different frequencies; the acoustic receiving unit is composed of a slidable fixture, a horizontal high-precision positioning long support rod, a standard vector microphone and a signal acquisition analyzer to receive the sound field information at a certain position in the full anechoic chamber; The MTIT thermal field monitoring unit consists of a slidable fixture, a horizontal high-precision positioning short support rod, a refrigerated focal plane detector and an infrared microscope objective lens, which is used to monitor the real-time changes in the thermal field of the hot-wire MEMS sensor thermal sensing module. The acoustic emission unit, the acoustic receiving unit and the MTIT thermal field monitoring unit work together through a computer and peripherals.

2. The measurement method of the hot-wire MEMS sensor test device based on micro-thermal imaging technology, Features: The hot-wire MEMS sensor testing device according to claim 1, wherein the steps are as follows: Step 1: Determine the relevant physical information of the hot wire MEMS sensor, including the spacing between the hot wires, the type of liquid filled inside, and the thermal conductivity, specific heat capacity and density of the liquid; Step 2: Build a horizontal and vertical high-precision positionable bracket, move the slidable fixture to the specified position, install the infrared microscope objective on the horizontal high-precision positioning short support rod, install the MEMS sensor to be tested and the standard vector microphone at the same height on the horizontal high-precision positioning long support rod, arrange the sound transmitter under the MEMS sensor to be tested and the standard vector microphone, and connect instruments including power amplifier, spectrometer, signal acquisition analyzer, refrigerated focal plane detector, computer and peripherals; Step 3: Start the sound transmitter to form a stable sound field in the test area. The sound field shows horizontal uniformity, that is, the sound pressure at each point at the same height should be equal, and record the ambient temperature value; Step 4: Use a standard vector microphone to obtain the sound field information in the test area and ensure that the sound field is in a stable state. At the same time, start the hot wire MEMS sensor, confirm the initial power value of the hot wire excitation, and record the real-time resistance temperature change value of the hot wire and the generated sound field information. In addition, start the infrared microscope objective lens to collect the internal temperature field distribution information of the hot wire MEMS sensor; Step 5: Import the data into the post-processing program. The post-processing program module calculates the temperature field perception sensitivity through the formula, and analyzes the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, the flow field calculated based on the MEMS three-suspended hot wire model in the hot-wire MEMS sensor and the real flow field, and the flow field calculated based on the MEMS three-suspended hot wire model by the MTIT and the real flow field.

3. The measuring method of the hot-wire MEMS sensor testing device based on microthermal imaging technology according to claim 2, Features: The calculation formula in step 5 is: M T-MTIT =T MTIT-center / p T MTIT-matched-degree =T / T MTIT-center Where M T-MTIT is the temperature field perception sensitivity, T MTIT-center is the temperature at the central hot line position of the hot wire MEMS sensor thermal sensing module obtained by microthermal imaging technology, p is the sound pressure value collected by the standard vector microphone, T MTIT-matched-degree is the matching degree between the thermal field output by the hot-wire MEMS sensor and the real thermal field output by the MTIT, T is the temperature value of the central hot wire, c f is the specific heat capacity of the liquid filled in the hot-wire MEMS sensor, ρ f is the density of the liquid filled in the hot wire MEMS sensor, u sim-centre is the theoretical flow velocity near the central hot wire of the hot wire MEMS sensor thermal sensing module, Δh is the distance between two adjacent hot wires, Q is the heat source power of the hot wire MEMS sensor, k is the thermal conductivity of the liquid filled in the hot wire MEMS sensor, T 1 ,T 2 ,T 3 are the temperatures of the upper, middle and lower hot wires, u sim-MTIT-centre The flow rate is calculated by using the temperature value of the hot wire of the thermal sensing module of the hot wire MEMS sensor obtained by microthermal imaging technology, T 1-MTIT ,T 2-MTIT ,T 3-MTIT are the temperatures of the upper, middle and lower hot wires obtained using microthermal imaging technology, u MTIT-matched-degree The matching degree between the flow field estimated by MTIT based on the MEMS three-suspended hot wire model and the real flow field, u sim-matched-degree The matching degree between the flow field estimated based on the MEMS three suspended hot wire model and the real flow field in the hot wire MEMS sensor, u real The particle velocity is acquired by a standard vector microphone.

4. The measuring method of the hot-wire MEMS sensor testing device based on microthermal imaging technology according to claim 2, Features: In step 2, the measurement device should be placed in a fully anechoic chamber environment to reduce the impact of environmental noise on the test.

5. The measuring method of the hot-wire MEMS sensor testing device based on microthermal imaging technology according to claim 2, Features: In step 4, the hot-wire MEMS sensor, standard vector microphone and infrared microscope objective lens realize synchronous real-time acquisition.

6. The measuring method of the hot-wire MEMS sensor testing device based on microthermal imaging technology according to claim 3, Features: In step five, based on the MEMS three-suspended hot wire model of steady-state heat transfer, the finite difference method is used to obtain the flow field data near the central hot wire.

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