A delay line type surface acoustic wave voltage sensor and voltage detection method

Abstract

The present application provides a delay line type surface acoustic wave voltage sensor and a voltage detection method. The voltage sensor includes: a piezoelectric crystal; a first interdigital electrode; a second interdigital electrode; a sensitive film; and a coil. The delay line type surface acoustic wave voltage sensor designed in the present application uses a coil to apply the magnetic field generated by the voltage signal to the sensitive film, inducing the sensitive film to produce a magnetoresistance or magnetostriction effect, and acting on the surface acoustic wave, thereby utilizing the conversion mechanism between electro-magnetic-acoustic to decouple the voltage information from the frequency / phase / amplitude and other information of the surface acoustic wave. The delay line type surface acoustic wave voltage sensor designed in the present application has the characteristics of miniature, fast response and high sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage sensors, and in particular to a delay line type surface acoustic wave voltage sensor and a voltage detection method. Background Art

[0002] Voltage sensors are widely used in automatic detection, renewable energy systems, transportation and other fields. At present, common voltage sensor detection principles include D-dot principle, electroluminescence effect, leakage current measurement principle, space electric field effect voltage division principle, stray capacitance voltage division principle and common voltage transformer voltage measurement principle. The commonly used capacitor-resistor voltage division and resistor-capacitor voltage division methods have poor accuracy and transient properties due to the influence of stray capacitance and temperature on the voltage division. The space electric field voltage division principle and the stray capacitance voltage division principle have the problem of poor accuracy. The method of measuring voltage based on leakage current has high requirements on the accuracy of the current sensor due to its small leakage current. At the same time, it is easily affected by the noise of the signal processing circuit, and it is difficult to ensure accuracy. The voltage sensor based on the D-dot principle has a small volume and will not have the problem of magnetic saturation, but the electric field distribution generated by its wire is easily affected by environmental factors, and the long-term stability cannot be guaranteed. The voltage sensor based on the electroluminescence principle has the advantages of small size, light weight and simple structure, but its measurement error, sensitivity, measurement range and high requirements on the physical and chemical properties of electroluminescent materials make it difficult to be practical.

[0003] In 1983, Joshi proposed the surface acoustic wave voltage sensor, the basic principle of which is to apply a bias electric field on the sound propagation path, thereby affecting the propagation characteristics of the surface acoustic wave and decoupling the voltage signal from the frequency change. However, this method has low sensitivity, with a frequency-voltage coefficient of about 1.22ppm / V.

[0004] Currently, voltage sensors have the problems of large size, slow response speed and low sensitivity. Summary of the invention

[0005] The purpose of this application is to solve the defects in the prior art.

[0006] The present application provides a delay line type surface acoustic wave voltage sensor and a voltage detection method which are miniature, highly sensitive and fast responding.

[0007] In the first aspect, the present application provides a delay line type surface acoustic wave voltage sensor, comprising: a piezoelectric crystal; a first interdigitated electrode, deposited on the surface of the piezoelectric crystal, for exciting surface acoustic waves; a second interdigitated electrode, deposited on the surface of the piezoelectric crystal, for receiving surface acoustic waves propagating through the piezoelectric crystal; a sensitive film, deposited on the surface of the piezoelectric crystal and located between the first interdigitated electrode and the second interdigitated electrode; a coil, for receiving a voltage signal to be measured and exciting a magnetic field corresponding to the voltage signal to be measured; wherein, under the action of the magnetic field corresponding to the voltage signal to be measured, the sensitive film produces a magnetoresistance change or a magnetostriction change, thereby affecting the surface acoustic wave propagating through the piezoelectric crystal; based on the surface acoustic wave propagated through the piezoelectric crystal received by the second interdigitated electrode, the voltage information of the voltage signal to be measured is obtained.

[0008] In a feasible embodiment, the voltage sensor also includes: a detection voltage positive terminal, used to input the voltage signal to be measured, located at one end of the coil and deposited on the surface of the piezoelectric crystal; a detection voltage negative terminal, used to output the voltage signal to be measured, located at the other end of the coil and deposited on the surface of the piezoelectric crystal.

[0009] In a feasible embodiment, the voltage sensor further includes: the first interdigitated electrode and the second interdigitated electrode are respectively located on opposite sides symmetrically distributed with respect to the sensitive film; and / or the coil is located on the inner side and / or the outer side of the first interdigitated electrode and the second interdigitated electrode, and is deposited on the surface of the piezoelectric crystal.

[0010] In a feasible embodiment, the sensitive film includes: classified by performance, the sensitive film can be one or more of a sensitive film with a magnetoresistance effect or a sensitive film with a magnetostrictive effect; or classified by material, the sensitive film can be one or more of a metal nickel film, a nickel-containing alloy film, a terbium-dysprosium-iron alloy film, an iron-gallium alloy film, and an iron-cobalt alloy film; or classified by graphic design, the sensitive film can be one or more of a circular sensitive film, a square sensitive film, a point-shaped sensitive film, a block-shaped sensitive film, and a grating-shaped sensitive film.

[0011] In a feasible embodiment, the coil includes: a coil with a number of turns between 1 and 1000, a width between 1nm and 1cm, and a thickness between 1nm and 1cm; or a coil made of one or more metal materials such as metal aluminum, platinum, gold, copper, palladium, or one or more alloy materials such as iron-aluminum, iron-platinum, palladium-copper, iron-nickel, aluminum-copper, or one or more semiconductor materials such as silicon, germanium, gallium arsenide, etc.; or a coil with a multi-layer alloy film structure, such as a chromium / aluminum double-layer film structure; or in order to increase the adhesion between the coil and the piezoelectric crystal, a metal such as chromium, tantalum, etc. is added between the piezoelectric crystal and the coil to form a multi-layer composite film coil; or a coil deposited on the surface of the piezoelectric crystal with a sensitive film as the center, and surrounding the first interdigital transducer, the second interdigital transducer, and the periphery of the area where the sensitive film is located based on a semiconductor planar process.

[0012] In a feasible embodiment, the piezoelectric crystal includes: the piezoelectric crystal may be one or more of lithium niobate, lithium tantalate, quartz, and lanthanum gallium silicate.

[0013] In a feasible embodiment, the first interdigitated electrode and the second interdigitated electrode include: the first interdigitated electrode can be one or more of a uniform finger structure or a SPUDTs structure, and the second interdigitated electrode can be one or more of a uniform finger structure or a SPUDTs structure; or the material of the first interdigitated electrode can be one or more of metal aluminum, platinum, and copper, and the material of the second interdigitated electrode can be one or more of metal aluminum, platinum, and copper.

[0014] In a feasible embodiment, the voltage sensor further includes: the working frequency of the working device of the voltage sensor is 80MHz to 2.4GHz, and the working device includes the first interdigital electrode, the piezoelectric crystal, the coil, the sensitive film, and the second interdigital electrode.

[0015] In the second aspect, the present application provides a voltage detection method based on the voltage sensor, including: a coil receives a voltage signal to be measured and excites a magnetic field corresponding to the voltage signal to be measured; under the action of the magnetic field corresponding to the voltage signal to be measured, the sensitive film produces a magnetoresistance change or a magnetostriction change; the first interdigitated electrode excites a surface acoustic wave, which is transmitted through the piezoelectric crystal and the sensitive film that produces a magnetoresistance change or a magnetostriction change, and is received by the second interdigitated electrode; the surface acoustic wave received by the second interdigitated electrode is analyzed to obtain voltage information of the voltage signal to be measured.

[0016] In a feasible embodiment, the surface acoustic wave received by the second interdigitated electrode is analyzed to obtain the voltage information of the voltage signal to be measured, including: analyzing one or more of the frequency change, phase change, and amplitude change of the surface acoustic wave received by the second interdigitated electrode, and decoupling to obtain the voltage information of the voltage signal to be measured.

[0017] The present application provides a delay line type surface acoustic wave voltage sensor and a voltage detection method. The voltage sensor includes: a piezoelectric crystal; a first interdigitated electrode; a second interdigitated electrode; a sensitive film; and a coil. The voltage detection method includes: the coil receives a voltage signal to be measured and excites a corresponding magnetic field; under the action of the magnetic field, the sensitive film produces a magnetoresistance change or a magnetostriction change; the first interdigitated electrode excites a surface acoustic wave, which is transmitted through the piezoelectric crystal and the sensitive film and is received by the second interdigitated electrode; the surface acoustic wave received by the second interdigitated electrode is analyzed to obtain voltage information of the voltage signal to be measured.

[0018] The delay line type surface acoustic wave voltage sensor designed in the present application uses a coil to apply the magnetic field generated by the voltage signal to be measured to a sensitive film, inducing the sensitive film to produce a magnetoresistance or magnetostriction effect, and acting on the surface acoustic wave, thereby utilizing the conversion mechanism between electricity, magnetism and sound to decouple voltage information from the frequency / phase / amplitude and other information of the surface acoustic wave. The delay line type surface acoustic wave voltage sensor designed in the present application has the characteristics of miniature, fast response and high sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A structural schematic diagram of a delay line type surface acoustic wave voltage sensor according to an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a flow chart of a voltage detection method according to an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the response results of a delay line surface acoustic wave voltage sensor according to an embodiment of the present invention;

[0022] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0023] Detection voltage positive terminal-1, detection voltage negative terminal-2, sensitive film-3, first interdigital electrode-4, second interdigital electrode-5, coil-6, piezoelectric crystal-7. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by technicians in the technical field without making creative work are within the scope of protection of the present invention.

[0025] In order to make the public have a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention. For those skilled in the art, the present invention can be fully understood without the description of these details.

[0026] The embodiment of the present invention proposes a new type of surface acoustic wave voltage sensor that is different from previous studies, a delayed line surface acoustic wave voltage sensor, which deposits a sensitive film with magnetoresistance or magnetostriction effect on the sound propagation path between the input and output interdigital electrodes, deposits a coil on the surface of the piezoelectric crystal, passes the detection voltage into the coil, excites the magnetic field, and then affects the characteristics of the sensitive film, and uses the conversion mechanism of the multi-physical field between electricity, magnetism and sound to decouple the voltage information from the frequency / phase change of the surface acoustic wave. The voltage sensor of the embodiment of the present invention has the characteristics of miniature, fast response and high sensitivity.

[0027] Figure 1 FIG. 1 is a schematic diagram of the structure of a delay line type surface acoustic wave voltage sensor according to an embodiment of the present invention. Figure 1 As shown, the embodiment of the present invention discloses a delay line type surface acoustic wave voltage sensor, which includes a piezoelectric crystal 7, a first interdigital electrode 4, a second interdigital electrode 5, a sensitive film 3, a coil 6, a detection voltage positive terminal 1, and a detection voltage negative terminal 2. The sensitive film 3 is deposited on the surface of the piezoelectric crystal 7, and the deposition coil 6 surrounds the periphery of the first interdigital electrode 4, the second interdigital electrode 5, and the sensitive film 3. The deposition coil 6 can also surround the area where the first interdigital electrode 4, the second interdigital electrode 5, and the outside of the sensitive film 3 are located, or the deposition coil 6 surrounds the area where the first interdigital electrode 4, the second interdigital electrode 5, and the outside of the sensitive film 3 are located.

[0028] Preferably, a detection voltage positive terminal and a detection voltage negative terminal are deposited at both ends of the coil respectively.

[0029] Preferably, the sensitive film is a magnetosensitive film, including a film having magnetostrictive effect and magnetoresistance effect. Preferably, the sensitive film is metal nickel, iron gallium film, iron cobalt film, terbium dysprosium iron film or nickel-containing alloy film.

[0030] Preferably, the magnetic sensitive film can be designed in a graphical manner, including one or a combination of square, dot, circle, block, and grid shapes.

[0031] Preferably, the coil is deposited on the surface of the piezoelectric crystal with the sensitive film as the center and around the input IDT, the output IDT and the periphery of the area where the sensitive film is located based on a semiconductor planar process.

[0032] Preferably, the number of turns of the coil is between 1 and 1000, the width is between 1 nm and 1 cm, and the thickness is between 1 nm and 1 cm. Preferably, the number of turns of the coil is 10, the width is 100 nm, and the thickness is 120 nm.

[0033] Preferably, the coil material can be selected from metal materials such as aluminum, platinum, gold, copper, palladium, etc.; it can also be alloy materials such as palladium copper, iron nickel, aluminum copper, etc.; it can also be semiconductor materials such as silicon, germanium, gallium arsenide, etc.

[0034] Preferably, in order to increase the adhesion between the coil and the piezoelectric crystal, metal, such as chromium, tantalum, etc., is added between the piezoelectric crystal and the coil to form a multi-layer composite thin film coil.

[0035] Preferably, the piezoelectric crystal may be selected from lithium niobate, lithium tantalate, quartz, lanthanum gallium silicate, and the like.

[0036] Preferably, the operating frequency of the surface acoustic wave voltage sensor is between 80 MHz and 2.4 GHz.

[0037] Preferably, the input interdigital electrodes and the output interdigital electrodes are deposited inside the coil on adjacent sides of the sensitive film, or are symmetrically distributed.

[0038] Preferably, the input interdigital electrodes and the output interdigital electrodes may be of uniform finger or SPUDT structures.

[0039] Preferably, the first interdigital electrodes are used as input interdigital electrodes and the second interdigital electrodes are used as output interdigital electrodes, the number of finger pairs is 100 pairs respectively, the spacing between the input interdigital electrodes and the output interdigital electrodes is 100λ, the aperture is 100λ, and λ is the wavelength of the surface acoustic wave.

[0040] Preferably, the input interdigital electrodes and the output interdigital electrodes are deposited on the surface of the piezoelectric crystal based on a semiconductor planar process, and the materials may be selected from metals such as aluminum, copper, platinum, gold, or multilayer metal film materials such as aluminum / copper.

[0041] Figure 2 FIG. 1 is a flow chart of a voltage detection method according to an embodiment of the present invention. Figure 2 The embodiment of the present application provides a voltage detection method based on the voltage sensor, comprising:

[0042] Step S110, the coil receives the voltage signal to be measured, and excites the magnetic field corresponding to the voltage signal to be measured;

[0043] Step S120, under the action of the magnetic field corresponding to the voltage signal to be measured, the sensitive film produces a magnetoresistance change or a magnetostriction change;

[0044] Step S130, the first interdigital electrode excites a surface acoustic wave, which is transmitted through the piezoelectric crystal and the sensitive film that produces a magnetoresistance change or a magnetostriction change, and is received by the second interdigital electrode;

[0045] Step S140: analyzing the surface acoustic wave received by the second interdigital electrode to obtain voltage information of the voltage signal to be measured.

[0046] In step S140, the surface acoustic wave received by the second interdigitated electrode is analyzed to obtain voltage information of the voltage signal to be measured, including: analyzing one or more of the frequency change, phase change, and amplitude change of the surface acoustic wave received by the second interdigitated electrode, and decoupling to obtain the voltage information of the voltage signal to be measured.

[0047] A voltage detection method of a delay line type surface acoustic wave voltage sensor of an embodiment of the present invention is to deposit a sensitive film with magnetoresistance or magnetostriction effect on the sound propagation path between the input and output interdigital electrodes, deposit a coil on the surface of the piezoelectric crystal, pass the detection voltage into the coil, excite the magnetic field, and then affect the characteristics of the sensitive film, and use the conversion mechanism of the multi-physical field between electricity, magnetism and sound to decouple the voltage information from the frequency / phase change of the surface acoustic wave. The voltage sensor of the present invention has the characteristics of miniature, fast response and high sensitivity.

[0048] Example 1

[0049] like Figure 1 As shown, an embodiment of the present invention discloses a delay line type surface acoustic wave voltage sensor, which includes a piezoelectric crystal, an input interdigital electrode, an output interdigital electrode, a sensitive film, a coil, a detection voltage positive terminal, and a detection voltage negative terminal.

[0050] A rectangular iron-nickel alloy film with a length, width and height of 120λ×100λ×0.01λ is deposited on the surface of a Y-cut piezoelectric quartz crystal by magnetron sputtering, where λ=15.8um is the wavelength of the surface acoustic wave. 80 pairs of metal aluminum input interdigital electrodes and 80 pairs of metal aluminum output interdigital electrodes are deposited at a distance of 1λ on both sides of the length direction of the iron-nickel film. The input interdigital electrodes and the output interdigital electrodes both adopt a uniform finger structure, the aperture size of the input and output interdigital electrodes is 120λ, and the electrode film thickness is The coil starts with the positive terminal of the detection voltage and takes the center of the iron-nickel alloy film as the center of the circle. Ten turns of the metal aluminum coil are deposited around the area surrounded by the input and output interdigital electrodes and the iron-nickel alloy film. The negative terminal of the detection voltage is deposited at the other end of the coil. The coil width is 100nm and the film thickness is The positive terminal of the detection voltage and the negative terminal of the detection voltage are made of metal aluminum, with a length and width of 10λ×10λ respectively and a thickness of

[0051] like Figure 3 The figure shows the response result of the invented surface acoustic wave voltage sensor. It can be seen from the figure that within the voltage range of 0 to 40V, the surface acoustic wave voltage sensor has the characteristics of fast response (~1s) and high sensitivity (~1.2° / V).

[0052] Any contents not described in detail in the present invention can be based on the conventional technical knowledge in the art.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A delay line type surface acoustic wave voltage sensor, characterized in that: include: Piezoelectric crystals; A first interdigital electrode, deposited on the surface of the piezoelectric crystal, for exciting surface acoustic waves; A second interdigital electrode, deposited on the surface of the piezoelectric crystal, for receiving the surface acoustic wave propagating through the piezoelectric crystal; A sensitive film is deposited on the surface of the piezoelectric crystal and is located between the first interdigital electrode and the second interdigital electrode; the first interdigital electrode and the second interdigital electrode are respectively located on opposite sides symmetrically distributed with respect to the sensitive film; A coil, used for receiving a voltage signal to be measured and exciting a magnetic field corresponding to the voltage signal to be measured; the coil is located on the inner side and / or outer side of the first interdigital electrode and the second interdigital electrode, and is deposited on the surface of the piezoelectric crystal; the coil is deposited on the surface of the piezoelectric crystal, with the sensitive film as the center, around the first interdigital transducer, the second interdigital transducer and the periphery of the area where the sensitive film is located based on a semiconductor planar process; A detection voltage positive terminal, used for inputting the voltage signal to be measured, located at one end of the coil and deposited on the surface of the piezoelectric crystal; A detection voltage negative terminal, used for outputting the voltage signal to be measured, located at the other end of the coil and deposited on the surface of the piezoelectric crystal; Among them, under the action of the magnetic field corresponding to the voltage signal to be measured, the sensitive film produces a magnetoresistance change or a magnetostriction change, thereby affecting the surface acoustic wave propagating through the piezoelectric crystal; based on the surface acoustic wave propagated through the piezoelectric crystal received by the second interdigitated electrode, the voltage information of the voltage signal to be measured is obtained.

2. The voltage sensor according to claim 1, characterized in that: The sensitive film comprises: According to the performance classification, the sensitive film is a sensitive film with magnetoresistance effect or a sensitive film with magnetostrictive effect; Or classified by material, the sensitive film is one or more of a metal nickel film, a nickel-containing alloy film, a terbium-dysprosium-iron alloy film, an iron-gallium alloy film, and an iron-cobalt alloy film; Alternatively, according to the graphic design classification, the sensitive film is one or more of a circular sensitive film, a square sensitive film, a point-shaped sensitive film, a block-shaped sensitive film, and a grating-shaped sensitive film.

3. The voltage sensor according to claim 1, characterized in that: The coil comprises: Coils with a number of turns between 1 and 1000, a width between 1nm and 1cm, and a thickness between 1nm and 1cm; The coil is made of one or more metal materials including aluminum, platinum, gold, copper, and palladium, or one or more alloy materials including iron-aluminum, iron-platinum, palladium-copper, iron-nickel, and aluminum-copper, or one or more semiconductor materials including silicon, germanium, and gallium arsenide; Or the material of the coil is a multi-layer alloy film structure, wherein the multi-layer alloy film structure includes a chromium / aluminum double-layer film structure; Alternatively, in order to increase the adhesion between the coil and the piezoelectric crystal, metal is added between the piezoelectric crystal and the coil, and the metal includes chromium and tantalum to form a multi-layer composite thin film coil.

4. The voltage sensor according to claim 1, characterized in that: The piezoelectric crystal comprises: The piezoelectric crystal is one or more of lithium niobate, lithium tantalate, quartz, and lanthanum gallium silicate.

5. The voltage sensor according to claim 1, characterized in that: The first interdigital electrode and the second interdigital electrode include: The first interdigitated electrode is one or more of a uniform finger structure or a SPUDTs structure, and the second interdigitated electrode is one or more of a uniform finger structure or a SPUDTs structure; Alternatively, the material of the first interdigital electrode is one or more of metal aluminum, platinum, and copper, and the material of the second interdigital electrode is one or more of metal aluminum, platinum, and copper.

6. The voltage sensor according to claim 1, characterized in that: Also includes: The working frequency of the working device of the voltage sensor is 80 MHz to 2.4 GHz, and the working device includes the first interdigital electrodes, the piezoelectric crystal, the coil, the sensitive film, and the second interdigital electrodes.

7. A voltage detection method based on the voltage sensor according to claim 1, characterized in that: include: The coil receives the voltage signal to be measured and excites the magnetic field corresponding to the voltage signal to be measured; Under the action of the magnetic field corresponding to the voltage signal to be measured, the sensitive film produces a magnetoresistance change or a magnetostriction change; The first interdigital electrode excites a surface acoustic wave, which is transmitted through the piezoelectric crystal and the sensitive film that produces a magnetoresistance change or a magnetostriction change, and is received by the second interdigital electrode; The surface acoustic wave received by the second interdigital electrode is analyzed to obtain voltage information of the voltage signal to be measured.

8. The voltage detection method according to claim 7, characterized in that: The step of analyzing the surface acoustic wave received by the second interdigitated electrode to obtain voltage information of the voltage signal to be measured includes: One or more signals of the frequency change, phase change, and amplitude change of the surface acoustic wave received by the second interdigital electrode are analyzed, and voltage information of the voltage signal to be measured is obtained by decoupling.

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