A love wave icing sensor with self-icing function and a preparation method thereof

Abstract

The application relates to the field of icing and deicing monitoring, in particular to a Love wave icing sensor with a self-deicing function and a preparation method; the sensor provided by the application is provided with, in sequence from top to bottom of a piezoelectric substrate (1), a first micro-heater (501), an input transducer (3), a PDMS (polydimethylsiloxane) micro-fluidic chip, an output transducer (4) and a second micro-heater (502); the PDMS micro-fluidic chip and a chip packaging fence jointly form a PDMS water storage cavity (6). The application realizes the integration of the micro-heater and the Love wave sensor device by using the MEMS process, controls through a temperature acquisition circuit and a heating control circuit, opens the deicing function at the same time when the ice appears, has good real-time performance and operability, realizes the integration of the icing monitoring and the deicing, and encapsulates the device surface by using the water storage cavity (6), so that the electrode short circuit caused by water leakage is prevented.

Description

TECHNICAL FIELD

[0001] The application relates to the field of icing and deicing monitoring, and particularly relates to a Love wave icing sensor with a self-deicing function and a preparation method. BACKGROUND

[0002] When an airplane flies in a cloud layer containing supercooled water droplets, supercooled water will freeze and cause icing on many key components of the airplane body, such as the wing, tail, propeller, engine inlet and windshield. Light icing of the airplane will reduce the flight performance of the airplane, mainly manifested as a decrease in lift, an increase in resistance, a significant decrease in lift-drag ratio, and the like, thereby causing the airplane to stall at a small angle of attack or causing the control surfaces to fail, and the like, and thus causing the airplane to be destroyed and people to be killed. Therefore, accurate monitoring and early warning of the icing state of the key parts of the airplane, and real-time starting of the airplane deicing system, are the basic premise and key link of the icing protection of the airplane. Foreign research on icing detection technology began in the 1950s, and by the mid-1980s, the icing sensor had become a standard device for many military and civilian airplanes in the United States. The principles of the typical icing monitoring technologies mainly include optical fiber, magnetostrictive and piezoelectric flat film technologies. The above icing sensing technologies can all give an icing signal of the airplane and start the deicing system of the airplane. However, there is little consideration for the deicing of the icing sensor itself at present.

[0003] The surface acoustic wave sensor meets the development trend of icing monitoring in the fields of aviation and rail transportation due to its small size and wireless and passive measurement characteristics. Love wave is a shear polarized surface wave propagating in a layered structure, that is, a waveguide thin layer is covered on the surface of a piezoelectric substrate supporting the propagation of a horizontal shear type surface acoustic wave (SH-SAW), and the elastic wave excited in the substrate is coupled into the surface waveguide thin layer, thereby effectively reducing the attenuation of the acoustic wave. The basic principle of the Love wave icing sensing is that the corresponding changes in the propagation speed and acoustic attenuation of the surface acoustic wave caused by the physical effects such as mass load of the icing process are used to realize real-time monitoring of the icing state and thickness. Compared with the icing monitoring technologies such as optical fiber, magnetostrictive and piezoelectric flat film, the surface acoustic wave technology has the characteristics of miniaturization, low power consumption, fast response, high sensitivity and strong anti-interference, and in particular, the electromagnetic wave excitation principle can realize the "passive" sensing of the sensor and the "wireless" transmission of the sensing signal, thereby meeting the development trend of icing monitoring in the fields of aviation and rail transportation.

[0004] Patent 201811603907.1 discloses an icing sensor based on a surface acoustic wave oscillator, comprising a surface acoustic wave device and an oscillation circuit, a packaging tube, and a water-permeable membrane; the surface acoustic wave device is packaged with a packaging tube; the water-permeable membrane is arranged at an opening of the packaging tube; the surface of the surface acoustic wave oscillator is covered with a SiO2 protective thin layer; the surface acoustic wave device outputs an electrical signal with a change in oscillation frequency to the oscillation circuit, and the oscillation circuit detects the mutation of the oscillation frequency of the electrical signal and outputs the oscillation frequency to realize icing early warning and monitoring. The icing sensor has high detection sensitivity, good temperature stability, can timely warn icing, and makes the surface acoustic wave technology easier to implement. Water vapor passes through the water-permeable membrane and freezes on the surface of the SiO2 protective thin layer, so that the surface acoustic wave device outputs an electrical signal with a change in oscillation frequency to the oscillation circuit, thereby performing icing monitoring.

[0005] The icing sensor based on a surface acoustic wave oscillator disclosed in patent 201811603907.1 is not packaged, and has poor airtightness; the technical solution disclosed is that water vapor passing through the water-permeable membrane directly freezes on the protective thin layer; once the protective thin layer is broken, water vapor, ice layer or melted water will directly contact the surface acoustic wave oscillator; water leakage will cause inaccurate icing monitoring, electrode short circuit or damage of the icing sensor. The icing sensor based on a surface acoustic wave oscillator disclosed in patent 201811603907.1 also does not have a self-icing function; since the air-permeable membrane blocks water vapor, water vapor will directly freeze on the water-permeable membrane when the air temperature is low, so that water vapor may not penetrate the surface of the sensor; in the actual application process, residual liquid will also be retained on the surface of the sensor chip, which cannot be recovered in time, thereby affecting the accuracy of the sensor.

[0006] The present application provides a Love wave icing sensor with a self-icing function and a preparation method thereof, which has the characteristics of small volume, high sensitivity, good temperature stability, simple process, etc. The micro-heater and Love wave sensor device are integrated through the MEMS process, effectively solving the problems of real-time icing monitoring and sensor deicing. SUMMARY

[0007] The purpose of this invention is to address the problems of poor real-time performance, difficulty in implementation, and lack of de-icing capability in existing icing sensors. It proposes a Leff wave icing sensor with self-de-icing function and its fabrication method. This results in a sensor with advantages such as miniaturization, high sensitivity, fast response, low power consumption, and low cost, improving the sensitivity, stability, and real-time performance of icing detection and de-icing, and making surface acoustic wave technology easier to implement. The Leff wave icing sensor with self-de-icing function proposed in this invention includes: a piezoelectric substrate 1, a waveguide layer 2, an input transducer 3, an output transducer 4, a water-permeable membrane 7, and a metal encapsulation shell 8. A first microheater 501, an input transducer 3, a PDMS microfluidic chip, an output transducer 4, and a second microheater 502 are sequentially arranged on the piezoelectric substrate 1.

[0008] The PDMS microfluidic chip is bonded to the waveguide layer 2 and encapsulated using a chip packaging enclosure; the PDMS microfluidic chip and the PDMS microfluidic chip packaging enclosure together form the PDMS water storage cavity 6; wherein,

[0009] The PDMS microfluidic chip packaging enclosure is a rectangular frame composed of vertical partitions. The lower edge of the PDMS microfluidic chip packaging enclosure is bonded to the waveguide layer 2, and the upper edge of the PDMS microfluidic chip packaging enclosure is connected to the packaging cap of the metal packaging shell 8.

[0010] The metal encapsulation tube 8 has an opening at the corresponding position of the PDMS water storage cavity 6; the water-permeable membrane 7 is disposed at the opening of the metal encapsulation tube 8.

[0011] The first micro heater 501 and the second micro heater 502 include: a base layer 51, a lower insulating layer 522, a conductive layer 53 and an upper insulating layer 521 arranged from bottom to top;

[0012] The first micro heater 501 and the second micro heater 502 are bonded to the piezoelectric substrate 1 through the substrate layer 51 and connected to an external control circuit through the conductive layer 53.

[0013] The base layer should be made of a material with low thermal conductivity in order to reduce heat transfer loss and increase heating power.

[0014] As an improvement to the above-mentioned device, the input transducer 3 and the output transducer 4 are deposited on the piezoelectric substrate 1;

[0015] The waveguide layer 2 is deposited on the piezoelectric substrate 1, the input transducer 3, the output transducer 4, the first microheater 501, and the second microheater 502.

[0016] Metal encapsulation housing 8 is used to encapsulate surface acoustic wave devices;

[0017] The surface acoustic wave device comprises a piezoelectric substrate 1, a waveguide layer 2, an input transducer 3, an output transducer 4, a first micro-heater 501, a second micro-heater 502, and a PDMS water storage cavity 6.

[0018] The metal packaging tube 8 has a packaging cap at the top, and an opening is formed at the top of the packaging cap; the water-permeable membrane 7 is arranged at the opening of the metal packaging tube 8.

[0019] As an improvement of the above device, the conductive layer 53 is designed as a curved and serpentine structure, comprising a heating thin-film resistor 531, a temperature measuring thin-film resistor 532, and a contact electrode 533; wherein,

[0020] The heating thin-film resistor 531 is connected with the contact electrode 533, for converting electric energy into heat;

[0021] The temperature measuring thin-film resistor 532 is connected with another group of contact electrodes 533, for measuring the temperature of the heat generated by the heating thin-film resistor 531;

[0022] The contact electrode 533 is also connected with an external control circuit, for providing input current for the heating thin-film resistor 531 and the temperature measuring thin-film resistor 532; and for measuring the resistance value of the temperature measuring thin-film resistor 532 during the heating process of the heating thin-film resistor 531, and obtaining the temperature of the micro-heater based on the resistance-temperature characteristic of the temperature measuring thin-film resistor 532.

[0023] As an improvement of the above device, the external control circuit comprises a temperature acquisition circuit and a heating control circuit; wherein the temperature acquisition circuit comprises a semiconductor intelligent temperature sensor; the temperature acquisition circuit is used for acquiring the heat temperature measured by the temperature measuring thin-film resistor 532; and for converting the acquired heat temperature into a voltage signal and sending it to the heating control circuit.

[0024] The heating control circuit comprises a heating part and a control part; and is used for controlling the start of the heating thin-film resistor 531; wherein,

[0025] The heating part comprises a triode and a relay; and the control part comprises a single-chip microcomputer.

[0026] As an improvement of the above device, the material of the piezoelectric substrate 1 comprises 36°YX LiTaO3, 41°YX LiTaO3, 64°YX LiTaO3, or ST-90°X quartz crystal;

[0027] The material of the waveguide layer 2 comprises SU-8, PMMA, and SiO2; the thickness of the waveguide layer 2 is 1-3%λ; wherein λ is the acoustic wave wavelength along the acoustic wave propagation direction

[0028] The electrode thickness of the input transducer 3 and the output transducer 4 is 1% lambda to 1.5% lambda; the electrode is a gold electrode, an aluminum electrode or a gold-aluminum alloy electrode; wherein lambda is the wavelength of the sound wave along the sound wave propagation direction;

[0029] The water-permeable membrane 7 is a graphene oxide gas barrier water-permeable membrane or a polyvinyl alcohol-chitosan blended composite water-permeable membrane. The water-permeable membrane 7 is a water-permeable membrane with a pore size capable of permeating small water molecules, and has a permeation evaporation separation performance, so that water enters the surface of the sensor device, and water vapor passes through the water-permeable membrane. Under certain temperature and humidity conditions, ice formation can be realized in the PDMS water storage cavity.

[0030] To achieve another purpose of the present application, the present application provides a preparation method of a Love wave ice sensor with self-icing function, comprising the following steps:

[0031] The piezoelectric substrate 1 is sequentially provided with a first micro-heater 501, an input transducer 3, a PDMS micro-fluidic chip, an output transducer 4 and a second micro-heater 502; wherein,

[0032] The PDMS micro-fluidic chip is bonded with the waveguide layer 2, and is packaged by using a chip packaging enclosure; the PDMS micro-fluidic chip and the PDMS micro-fluidic chip packaging enclosure jointly form a PDMS water storage cavity 6; wherein,

[0033] The PDMS micro-fluidic chip packaging enclosure is a rectangular frame composed of vertical partitions, the lower edge of the PDMS micro-fluidic chip packaging enclosure is bonded with the waveguide layer 2, and the upper edge of the PDMS micro-fluidic chip packaging enclosure is connected with the packaging tube cap of the metal packaging tube shell 8;

[0034] The metal packaging tube shell 8 is provided with an opening at the position corresponding to the PDMS water storage cavity 6; the water-permeable membrane 7 is arranged at the opening of the metal packaging tube shell 8;

[0035] The first micro-heater 501 and the second micro-heater 502 comprise: a substrate layer 51, a lower insulating layer 522, a conductive layer 53 and an upper insulating layer 521 arranged in sequence from bottom to top;

[0036] The first micro-heater 501 and the second micro-heater 502 are bonded with the piezoelectric substrate 1 through the substrate layer 51, and are connected with an external control circuit through the conductive layer 53.

[0037] As an improvement of the above method, the manufacturing method of the PDMS micro-fluidic chip packaging enclosure comprises: a molding method.

[0038] As an improvement of the above method, the lower insulating layer 522, the conductive layer 53 and the upper insulating layer 521 of the first micro-heater 501 and the second micro-heater 502 are made by MEMS process.

[0039] As an improvement of the above method, the specific manufacturing process of the first micro-heater 501 and the second micro-heater 502 includes:

[0040] The substrate layer 51 is pretreated, and the pretreatment includes radio frequency plasma treatment, pre-bonding treatment and heat treatment; and the substrate layer 51 is bonded to the piezoelectric substrate 1 by chemical bond;

[0041] The lower insulating layer 522 is plated on the substrate layer 51;

[0042] The conductive layer 53 is made above the lower insulating layer 522 by sputtering process, and the conductive layer 53 is etched to obtain the required shape;

[0043] The upper insulating layer 521 is plated above the conductive layer 53.

[0044] As an improvement of the above method, the material of the conductive layer 53 includes aluminum, silver, copper, platinum, nickel, cadmium, aluminum-based composite material, silver-based composite material, copper-based composite material, platinum-based composite material, nickel-based composite material, cadmium-based composite material, positive temperature coefficient ceramic PTC ceramic or ferroelectric semiconductor ceramic; the thickness of the conductive layer 53 is 0.5% lambda to 20% lambda; the material of the upper insulating layer 521 and the lower insulating layer 522 includes silicon or silicon-based composite material; the thickness of the upper insulating layer 521 and the lower insulating layer 522 is 0.5% lambda to 5% lambda;

[0045] As an improvement of the above method, the materials of the substrate layer 51, the insulating layer 52 and the conductive layer 53 are combined with materials having strong adhesion to adjacent layers to enhance the performance and service life of the micro-heater as a whole.

[0046] The advantages of the present application are:

[0047] 1. The Love wave icing sensor with self-icing function and the preparation method thereof realize the integration of the micro-heater and the Love wave sensor device by MEMS process, control through the temperature acquisition circuit and the heating control circuit, open the icing function at the same time when there is ice, have good real-time and operability, and realize the integration of icing monitoring and icing.

[0048] 2、The micro-heater for deicing function of the present application adopts the multi-layer film process, combines with the stress elimination method and the reasonable collocation of each layer material, can overcome the defects of fragile structure, easy to break when rapidly heating and low wear resistance of ordinary micro-heaters, has the characteristics of high heating efficiency, high power resistance, stable work and long service life;

[0049] 3、The Love wave icing sensing device of the present application adopts the PDMS material to design the micro-fluidic chip and the chip packaging enclosure to jointly form the PDMS water storage cavity 6, bonds the micro-fluidic chip on the sensor, and uses the water storage cavity 6 to package the device surface, which can prevent water leakage from causing electrode short circuit. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a Love wave icing sensor principle structure schematic diagram provided by the embodiment 1 of the present application;

[0051] Figure 2 It is a micro-heater structure schematic diagram provided by the embodiment 1 of the present application;

[0052] Figure 3 It is a micro-heater multi-layer film stack schematic diagram provided by the embodiment 1 of the present application;

[0053] Figure 4 It is a Love wave overall device top view provided by the embodiment 1 of the present application;

[0054] Figure 5 It is a PDMS micro-fluidic chip position schematic diagram provided by the embodiment 1 of the present application;

[0055] Figure 6 It is a PDMS water storage cavity schematic diagram provided by the embodiment 1 of the present application.

[0056] BRIEF DESCRIPTION OF DRAWINGS

[0057] 1, piezoelectric substrate 2, waveguide layer 3, input transducer

[0058] 4, output transducer 501, first micro-heater 502, second micro-heater

[0059] 6, PDMS water storage cavity 7, water permeable membrane 8, metal packaging tube shell

[0060] 32, interdigital electrode 51, substrate layer 521, upper insulating layer

[0061] 53, conductive layer 522, lower insulating layer 531, heating thin film resistance

[0062] 532, temperature measuring thin film resistance 533, contact electrode DETAILED DESCRIPTION

[0063] The technical solutions provided by the present invention will be further illustrated below with reference to the embodiments.

[0064] like Figure 1 As shown, a Lefu wave icing sensor with self-de-icing function includes: a piezoelectric substrate 1, a waveguide layer 2, an input transducer 3, an output transducer 4, a water-permeable membrane 7, and a metal encapsulation shell 8. A first microheater 501, an input transducer 3, a PDMS microfluidic chip, an output transducer 4, and a second microheater 502 are sequentially disposed above the piezoelectric substrate 1.

[0065] The PDMS microfluidic chip is bonded to the waveguide layer 2 and encapsulated using a chip packaging enclosure; the PDMS microfluidic chip and the PDMS microfluidic chip packaging enclosure together form the PDMS water storage cavity 6; wherein,

[0066] The PDMS microfluidic chip packaging enclosure is a rectangular frame composed of vertical partitions. The lower edge of the PDMS microfluidic chip packaging enclosure is bonded to the waveguide layer 2, and the upper edge of the PDMS microfluidic chip packaging enclosure is connected to the packaging cap of the metal packaging shell 8.

[0067] The metal encapsulation tube 8 has an opening at the corresponding position of the PDMS water storage cavity 6; the water-permeable membrane 7 is disposed at the opening of the metal encapsulation tube 8.

[0068] The first micro heater 501 and the second micro heater 502 include: a base layer 51, a lower insulating layer 522, a conductive layer 53 and an upper insulating layer 521 arranged from bottom to top;

[0069] The first micro heater 501 and the second micro heater 502 are bonded to the piezoelectric substrate 1 through the substrate layer 51 and connected to an external control circuit through the conductive layer 53.

[0070] like Figure 3 As shown, the conductive layer 53 is designed as a curved serpentine structure, including: a heating thin-film resistor 531, a temperature-sensing thin-film resistor 532, and a contact electrode 533; wherein,

[0071] The heating thin-film resistor 531 is connected to the contact electrode 533; the temperature-sensing thin-film resistor 532 is connected to another set of contact electrodes 533; the contact electrode 533 is also connected to an external control circuit.

[0072] The external control circuit includes: a temperature acquisition circuit and a heating control circuit; wherein...

[0073] The temperature acquisition circuit includes: a semiconductor intelligent temperature sensor;

[0074] The heating control circuit comprises a heating part and a control part, wherein

[0075] The heating part comprises a triode and a relay, and the control part comprises a single-chip microcomputer.

[0076] The piezoelectric substrate 1 material comprises 36°YX LiTaO3, 41°YX LiTaO3, 64°YX LiTaO3 or ST-90°X quartz crystal;

[0077] The waveguide layer 2 material comprises epoxy resin (SU-8), polymethyl methacrylate (PMMA) and silicon dioxide (SiO2), and the waveguide layer 2 thickness is 1-3%λ, wherein λ is the acoustic wave wavelength along the acoustic wave propagation direction.

[0078] The electrode thickness of the input transducer 3 and the output transducer 4 is 1%λ-1.5%λ, and the electrode is a gold electrode, an aluminum electrode or a gold-aluminum alloy electrode, wherein λ is the acoustic wave wavelength along the acoustic wave propagation direction.

[0079] The water-permeable membrane 7 is a graphene oxide gas-proof water-permeable membrane or a polyvinyl alcohol-chitosan blended composite water-permeable membrane.

[0080] A preparation method of a Love wave icing sensor with a self-icing function, comprising the following steps:

[0081] The piezoelectric substrate 1 is sequentially provided with a first micro-heater 501, an input transducer 3, a PDMS micro-fluidic chip, an output transducer 4 and a second micro-heater 502, wherein

[0082] The PDMS micro-fluidic chip is bonded to the waveguide layer 2 and encapsulated by a chip encapsulation enclosure, and the PDMS micro-fluidic chip and the PDMS micro-fluidic chip encapsulation enclosure jointly form a PDMS water storage cavity 6, wherein

[0083] The PDMS micro-fluidic chip encapsulation enclosure is a rectangular frame composed of vertical partitions, the lower edge of the PDMS micro-fluidic chip encapsulation enclosure is bonded to the waveguide layer 2, and the upper edge of the PDMS micro-fluidic chip encapsulation enclosure is connected to the encapsulation tube cap of the metal encapsulation tube shell 8.

[0084] The metal encapsulation tube shell 8 encapsulation tube cap is provided with an opening at the corresponding position of the PDMS water storage cavity 6, and the water-permeable membrane 7 is arranged at the opening of the metal encapsulation tube shell 8.

[0085] The first micro-heater 501 and the second micro-heater 502 comprise a substrate layer 51, a lower insulating layer 522, a conductive layer 53 and an upper insulating layer 521 arranged in order from bottom to top.

[0086] The first micro-heater 501 and the second micro-heater 502 are bonded with the piezoelectric substrate 1 through the substrate layer 51 and connected with external control circuit through the conductive layer 53.

[0087] The method for manufacturing the PDMS micro-fluidic chip package enclosure comprises a molding method.

[0088] The lower insulating layer 522, the conductive layer 53 and the upper insulating layer 521 of the first micro-heater 501 and the second micro-heater 502 are manufactured by MEMS process.

[0089] The specific manufacturing process of the first micro-heater 501 and the second micro-heater 502 comprises:

[0090] The substrate layer 51 is pretreated, the pretreatment comprises radio frequency plasma treatment, pre-bonding treatment and heat treatment, and the substrate layer 51 is bonded with the piezoelectric substrate 1 through chemical bond bonding;

[0091] The lower insulating layer 522 is plated on the substrate layer 51.

[0092] The conductive layer 53 is manufactured above the lower insulating layer 522 by sputtering process, and the conductive layer 53 is etched to obtain the required shape.

[0093] The upper insulating layer 521 is plated above the conductive layer 53.

[0094] The material of the conductive layer 53 comprises aluminum, silver, copper, platinum, nickel, cadmium, aluminum-based composite material, silver-based composite material, copper-based composite material, platinum-based composite material, nickel-based composite material, cadmium-based composite material, positive temperature coefficient ceramic PTC ceramic or ferroelectric semiconductor ceramic, the thickness of the conductive layer 53 is 0.5% lambda to 20% lambda, the material of the upper insulating layer 521 and the lower insulating layer 522 comprises silicon or silicon-based composite material, and the thickness of the upper insulating layer 521 and the lower insulating layer 522 is 0.5% lambda to 5% lambda.

[0095] The materials of the substrate layer 51, the insulating layer 52 and the conductive layer 53 are combined by using materials with strong adhesion to adjacent layer materials.

[0096] Embodiment 1

[0097] The following takes Figure 1 as an example to illustrate the Love wave sensor device design and preparation method for the icing monitoring and deicing system provided in Embodiment 1 of the present application.

[0098] As Figure 1As shown, the Love wave-based icing sensor provided by the embodiment 1 of the present application comprises: a piezoelectric substrate 1, a waveguide layer 2, an input transducer 3, an output transducer 4, a water-permeable membrane 7 and a metal packaging tube 8, wherein the piezoelectric substrate 1 is sequentially provided with a first micro-heater 501, the input transducer 3, a PDMS micro-fluidic chip, the output transducer 4 and a second micro-heater 502 from top to bottom; wherein,

[0099] The PDMS micro-fluidic chip is bonded with the waveguide layer 2 and is packaged by a chip packaging enclosure; the PDMS micro-fluidic chip and the PDMS micro-fluidic chip packaging enclosure jointly form a PDMS water storage cavity 6; wherein,

[0100] The PDMS micro-fluidic chip packaging enclosure is a rectangular frame composed of vertical partitions, the lower edge of the PDMS micro-fluidic chip packaging enclosure is bonded with the waveguide layer 2, and the upper edge of the PDMS micro-fluidic chip packaging enclosure is connected with the packaging tube cap of the metal packaging tube 8;

[0101] The packaging tube cap of the metal packaging tube 8 is provided with an opening at the corresponding position of the PDMS water storage cavity 6; the water-permeable membrane 7 is arranged at the opening of the metal packaging tube 8;

[0102] The first micro-heater 501 and the second micro-heater 502 comprise: a substrate layer 51, a lower insulating layer 522, a conductive layer 53 and an upper insulating layer 521 arranged from bottom to top.

[0103] The first micro-heater 501 and the second micro-heater 502 are bonded with the piezoelectric substrate 1 through the substrate layer 51 and are connected with an external control circuit through the conductive layer 53.

[0104] The piezoelectric substrate 1 is a quartz piezoelectric substrate cut at 42.75° around Y and along 90° X. The input transducer 3 and the output transducer 4 adopt a one-way single-phase EWC / SPUDT structure, adopt aluminum electrodes and the electrode film thickness is 1%-1.5%λ.

[0105] The SU-8 film is used as the waveguide layer 2 and is used to protect the input transducer 3 and the output transducer 4. The waveguide layer can couple the elastic wave excited in the substrate into the surface wave waveguide layer 2, can reduce the attenuation of the acoustic wave and is extremely sensitive to the surface load, thereby effectively improving the detection sensitivity of the sensor.

[0106] The water storage device 6 is designed by using polydimethylsiloxane (PDMS) material, the PDMS microfluidic chip is bonded on the sensor through plasma treatment, and the PDMS microfluidic chip is packaged by using the packaging surrounding.

[0107] The water permeable membrane 7 is in communication with the outside, so that water molecules can pass through, and under certain temperature, humidity and wind speed conditions, ice can be formed in the PDMS water storage cavity, so that the acoustic mode can be changed through the waveguide effect, and the response phase and amplitude generated can realize ice warning; in addition, the increase of the ice layer thickness will increase the mass loading effect on the SAW, so as to cause the corresponding change of the phase and response amplitude, so as to realize the monitoring of the ice.

[0108] The first micro-heater 501 and the second micro-heater 502 are integrated with the Love wave device. A micro-heater is made on a substrate material by using MEMS process technology, and the shape is designed as a curved and serpentine structure. The heating thin film resistor 531 is used for heating, and the temperature measuring thin film resistor 532 is used for measuring the heating temperature. The contact electrode 533 is connected with the heating thin film resistor 531 and the temperature measuring thin film resistor 532, and is also connected with the external control circuit to provide input current and measure the resistance value of the temperature measuring thin film resistor.

[0109] The specific working process of the ice sensor device is as follows:

[0110] The input transducer 3 converts the input electrical signal into a surface acoustic wave signal propagating on the surface of the piezoelectric substrate 1, and the elastic wave excited in the substrate is coupled into the surface waveguide layer 2 to propagate through the waveguide effect. The output transducer 4 receives the converted Love wave signal and converts the Love wave signal into an electrical signal. After a certain time delay, the electrical signal output by the Love wave sensor can obtain the detected ice signal and ice thickness. When the ice signal is received, the first micro-heater 501 and the second micro-heater 502 are controlled by the external control circuit, and the voltage signal is applied to the first micro-heater 501 and the second micro-heater 502 by the external control circuit to realize heating. When the micro-heater reaches the specified temperature in the heating process and forms a stable temperature field on the surface of the substrate, the deicing operation is realized.

[0111] As Figure 1The shown Love wave ice sensor has a working frequency of 200 MHz. The input transducer 3 has a length of 201 λ and is divided into 4 groups, each group containing a comb tooth and a ground false finger electrode distributed between the comb teeth, the length of the comb tooth being 18 λ and the length of the ground false finger being 43 λ. The output transducer 4 has a length of 60 λ. The center distance between the input transducer 3 and the output transducer 4 is 200 λ. The piezoelectric substrate 1 and the surface of the output transducer 4 and the input transducer 3 are covered with a SU-8 waveguide layer 2, the film thickness being 1-3% λ. The length, width and height of the PDMS water storage cavity are 3.5 mm, 4 mm and 5 mm respectively.

[0112] As shown in Figure 2 , in order to facilitate the bonding of the quartz piezoelectric substrate, the micro-heater substrate layer 1 adopts quartz glass material, the thickness is 0.3 mm, the thermal expansion coefficient is 5.5x10 -7 / ℃; the silicon dioxide (SiO2) is selected as the material of the upper insulating layer 521 and the lower insulating layer 522, the thickness is 300 nm, the thermal expansion coefficient is 0.5x10 -6 / ℃; the metal platinum is selected as the material of the heating thin film resistor 531 and the temperature measuring thin film resistor 532 in the conductive layer, the thermal expansion coefficient is 9x10 -6 / ℃. The metal aluminum is used as the contact electrode 533, the thickness is 2000 nm, the thermal expansion coefficient is 23.2x10 -6 / ℃. The specific manufacturing process is: the lower insulating layer SiO2 522 is plated on the prepared quartz glass substrate layer 51, then the platinum conductive layer 53 is made on the lower insulating layer SiO2 522 by sputtering, the platinum conductive layer is etched to obtain the required shape, and then the SiO2 upper insulating layer 521 is plated on the platinum conductive layer 53. And in order to increase the success of plating before plating, the quartz glass substrate layer 51 is treated by radio frequency plasma. The prepared micro-heater is treated by surface treatment, pre-bonding and heat treatment, and the bonding is directly realized by using the Si-Si bond between the quartz piezoelectric substrate and the quartz glass.

[0113] As shown in Figure 3 , a micro-heater is made on the surface of the device by using MEMS process technology, the width of the part connected to the temperature measuring thin film resistor 532 in the conductive layer 53 is designed to be greater than the width of the temperature measuring thin film resistor 532, so as to be in full contact with the temperature measuring thin film resistor 532. Among them, the heating thin film resistor 531 is used for heating, and the temperature measuring thin film resistor 532 is used for measuring the heating temperature. The contact electrode 533 is connected with the heating thin film resistor 531 and the temperature measuring thin film resistor 532, and is also connected with the external control circuit, which provides input current and measures the resistance value of the temperature measuring thin film resistor.

[0114] From Figure 4It can be seen that the top view of the ice freezing and removing sensor device involved in the embodiment of the application is packaged by the PDMS water storage cavity 6 to avoid external environmental interference and ensure that no leakage occurs after water is loaded, the overall device is packaged by the metal packaging tube shell 8, and the ice freezing environment is provided by combining with the water permeable membrane 7.

[0115] The application has the characteristics of high heating efficiency, stable work and long service life by designing the key sensor device in the ice freezing and removing system and by integrating with the micro-heater to perform the ice removing treatment. The overall sensor device has the advantages of miniaturization, high sensitivity, fast response, low power consumption and low cost, effectively solves the problems of large size and unable to consider ice removing of the current ice freezing sensor. The Love wave ice freezing sensor device of the application uses the polydimethylsiloxane (PDMS) material to design the microfluidic chip and the chip packaging enclosure to jointly form the PDMS water storage cavity 6, bonds the microfluidic chip on the sensor, and uses the water storage cavity 6 to package the device surface, which can prevent water leakage from causing electrode short circuit.

[0116] Finally, it should be explained that the above embodiments are only used to illustrate the technical solutions of the application but not limit the application. Although the application is described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by the equivalent without departing from the spirit and scope of the application, which should be covered in the claim range of the application.

Claims

1. A Lefu wave icing sensor with self-de-icing function, comprising: The piezoelectric substrate (1), the waveguide layer (2), the input transducer (3), the output transducer (4), the water-permeable membrane (7) and the metal packaging tube shell (8) are characterized in that the first micro-heater (501), the input transducer (3), the PDMS micro-fluidic chip, the output transducer (4) and the second micro-heater (502) are sequentially arranged above the piezoelectric substrate (1); wherein, The PDMS micro-fluidic chip is bonded with the waveguide layer (2) and is packaged by using a chip packaging enclosure; the PDMS micro-fluidic chip and the PDMS micro-fluidic chip packaging enclosure jointly form a PDMS water storage cavity (6); wherein, The PDMS micro-fluidic chip packaging enclosure is a rectangular frame composed of vertical partitions, the lower edge of the PDMS micro-fluidic chip packaging enclosure is bonded with the waveguide layer (2), and the upper edge of the PDMS micro-fluidic chip packaging enclosure is connected with the packaging tube cap of the metal packaging tube shell (8); The metal packaging tube shell (8) is provided with an opening at the corresponding position of the PDMS water storage cavity (6); and the water-permeable membrane (7) is arranged at the opening of the metal packaging tube shell (8); The first micro-heater (501) and the second micro-heater (502) comprise a substrate layer (51), a lower insulating layer (522), a conductive layer (53) and an upper insulating layer (521) arranged in sequence from bottom to top; The first micro-heater (501) and the second micro-heater (502) are bonded with the piezoelectric substrate (1) through the substrate layer (51) and are connected with an external control circuit through the conductive layer (53).

2. The Lefu wave icing sensor with self-de-icing function according to claim 1, characterized in that, Comprise: The input transducer (3) and the output transducer (4) are deposited on the piezoelectric substrate (1); The waveguide layer (2) is deposited on the piezoelectric substrate (1), the input transducer (3), the output transducer (4), the first micro-heater (501) and the second micro-heater (502); The metal packaging tube shell (8) is used for packaging the surface acoustic wave device; The surface acoustic wave device comprises a piezoelectric substrate (1), a waveguide layer (2), an input transducer (3), an output transducer (4), a first micro-heater (501), a second micro-heater (502) and a PDMS water storage cavity (6); The metal packaging tube shell (8) has a packaging tube cap on the top and an opening on the top of the packaging tube cap; and the water-permeable membrane (7) is arranged at the opening of the metal packaging tube shell (8).

3. The Lefu wave icing sensor with self-de-icing function according to claim 1, characterized in that, The conductive layer (53) is designed as a curved and serpentine structure, comprising a heating thin-film resistor (531), a temperature measuring thin-film resistor (532) and a contact electrode (533); wherein, The heating thin-film resistor (531) is connected with the contact electrode (533); the temperature measuring thin-film resistor (532) is connected with another group of contact electrodes (533); and the contact electrode (533) is further connected with an external control circuit.

4. The Lep-wave icing sensor with self-de-icing function according to claim 1, characterized in that... The external control circuit comprises a temperature acquisition circuit and a heating control circuit; wherein, The temperature acquisition circuit comprises a semiconductor intelligent temperature sensor; The heating control circuit comprises a heating part and a control part; wherein, The heating part comprises a triode and a relay; the control part comprises a single-chip microcomputer.

5. The Lefu wave icing sensor with self-de-icing function according to claim 1, characterized in that, It comprises: The piezoelectric substrate (1) material comprises 36°YX LiTaO3, 41°YX LiTaO3, 64°YX LiTaO3 or ST-90°X quartz crystal; The waveguide layer (2) material comprises epoxy resin, polymethyl methacrylate and silicon dioxide; the waveguide layer (2) thickness is 1-3%λ; wherein λ is the acoustic wave wavelength along the acoustic wave propagation direction The electrode thickness of the input transducer (3) and the output transducer (4) is 1%λ-1.5%λ; the electrode is a gold electrode, an aluminum electrode or a gold-aluminum alloy electrode; wherein λ is the acoustic wave wavelength along the acoustic wave propagation direction; The water-permeable membrane (7) is a graphene oxide gas-proof water-permeable membrane or a polyvinyl alcohol-chitosan blended composite water-permeable membrane.

6. A preparation method of a Love wave icing sensor with self-icing function according to any one of claims 1-5, comprising the following steps: The piezoelectric substrate (1) is sequentially provided with a first micro-heater (501), an input transducer (3), a PDMS micro-fluidic chip, an output transducer (4) and a second micro-heater (502); wherein The PDMS micro-fluidic chip is bonded with the waveguide layer (2), and is packaged by using a chip packaging enclosure; the PDMS micro-fluidic chip and the PDMS micro-fluidic chip packaging enclosure jointly form a PDMS water storage cavity (6); wherein The PDMS micro-fluidic chip packaging enclosure is a rectangular frame composed of vertical partitions, the lower edge of the PDMS micro-fluidic chip packaging enclosure is bonded with the waveguide layer (2), and the upper edge of the PDMS micro-fluidic chip packaging enclosure is connected with the packaging tube cap of the metal packaging tube shell (8); The metal packaging tube shell (8) packaging tube cap is provided with an opening at the corresponding position of the PDMS water storage cavity (6); the water-permeable membrane (7) is arranged at the opening of the metal packaging tube shell (8); The first micro-heater (501) and the second micro-heater (502) comprise a substrate layer (51), a lower insulating layer (522), a conductive layer (53) and an upper insulating layer (521) arranged in order from bottom to top; The first micro-heater (501) and the second micro-heater (502) are bonded with the piezoelectric substrate (1) through the substrate layer (51), and are connected with an external control circuit through the conductive layer (53).

7. The method of claim 6, wherein the method further comprises the step of: The lower insulating layer (522), the conductive layer (53) and the upper insulating layer (521) of the first micro-heater (501) and the second micro-heater (502) are made by using a MEMS process; The manufacturing method of the PDMS micro-fluidic chip packaging enclosure comprises a molding method. ​ 8. The method of claim 6, wherein the method further comprises the step of: The specific manufacturing process of the first micro-heater (501) and the second micro-heater (502) comprises: ​ The substrate layer (51) is pretreated, the pretreatment comprises radio frequency plasma treatment, pre-bonding treatment and heat treatment; and the substrate layer (51) is bonded with the piezoelectric substrate (1) by chemical bond bonding; The lower insulating layer (522) is plated onto the base layer (51); A conductive layer (53) is fabricated above the lower insulating layer (522) by sputtering, and the conductive layer (53) is etched to obtain the desired shape; The upper insulating layer (521) is plated on top of the conductive layer (53).

9. The method of claim 6, wherein the method further comprises the step of: 9-1) forming a plurality of the Leontiev ice sensor on the substrate. The conductive layer (53) is made of materials including: aluminum, silver, copper, platinum, nickel, cadmium, aluminum-based composite material, silver-based composite material, copper-based composite material, platinum-based composite material, nickel-based composite material, cadmium-based composite material, positive temperature coefficient ceramic or ferroelectric semiconductor ceramic; the thickness of the conductive layer (53) is 0.5%λ to 20%λ; the upper insulating layer (521) and the lower insulating layer (522) are made of materials including: silicon or silicon-based composite material; the thickness of the upper insulating layer (521) and the lower insulating layer (522) is 0.5%λ to 5%λ, where λ is the wavelength of the sound wave along the direction of sound wave propagation.

10. The method for preparing the Lep-wave icing sensor with self-de-icing function according to claim 6, characterized in that, The materials of the base layer (51), insulating layer (52) and conductive layer (53) are combined with materials that have strong adhesion to the materials of adjacent layers.

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