CN114778958A - Piezoelectric drive-based field-grinding type MEMS electric field sensor - Google Patents
Piezoelectric drive-based field-grinding type MEMS electric field sensor Download PDFInfo
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- CN114778958A CN114778958A CN202210252347.XA CN202210252347A CN114778958A CN 114778958 A CN114778958 A CN 114778958A CN 202210252347 A CN202210252347 A CN 202210252347A CN 114778958 A CN114778958 A CN 114778958A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
- H10N30/304—Beam type
- H10N30/306—Cantilevers
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Abstract
The invention discloses a piezoelectric drive-based field-milling MEMS electric field sensor, which comprises an SOI substrate, wherein an L-shaped elastic beam, a shielding electrode and a piezoelectric drive structure are arranged on the SOI substrate, the shielding electrode is connected with the piezoelectric drive structure through the L-shaped elastic beam, and the vertical displacement of the piezoelectric drive structure is converted into the twisting or vertical displacement of the shielding electrode; the piezoelectric driving structure controls the modulation mode of the electric sensor: when the applied voltage phase difference of the two side piezoelectric driving structures is 180 degrees, the electric field is in a torsional vibration modulation mode, and when the applied voltage phase difference of the two side piezoelectric driving structures is equal, the electric field is in a piston vibration modulation mode. The invention has two working modes of a torsion modulation mode and a piston modulation mode, and the microstructure has high resonance frequency and can realize electric field high-frequency modulation. The sensor adopts an advanced piezoelectric driving mode and structure, and has the advantages of low power consumption, high sensitivity and controllable vibration mode.
Description
Technical Field
The invention relates to the field of miniature electric field sensors, in particular to a piezoelectric drive-based field-milling MEMS electric field sensor.
Background
The electric field is not only an important monitoring object on the equipment, but also an important state quantity on the network node and the line. Electric field measurement electric power grid has important application in a plurality of scenes, such as transmission line corridor electromagnetic environment monitoring and line non-contact voltage measurement. The traditional electric field sensor has the defects of high power consumption, large volume, low measurement precision and the like, and is difficult to produce in batches. The MEMS electric field sensor has the advantages of small volume, low power consumption, high precision, batch production and the like, and is suitable for large-scale deployment of a power grid and comprehensive information perception requirements.
At present, a field-grinding type MEMS electric field sensor mostly adopts an electrostatic driving mode and a thermal driving mode, and has the defects of large distortion influence on an electric field to be detected, large driving voltage, low precision and sensitivity and the like. Although the piezoelectric driving mode theoretically has the advantages of small driving voltage, small interference and the like, the piezoelectric driving mode is not mature and needs to be researched for a novel adaptive piezoelectric driving structure and an MEMS sensitive structure.
Disclosure of Invention
One of the keys of the traditional field grinding type electric field sensor is how to modulate, and the invention provides a novel field grinding type MEMS electric field sensor structure based on piezoelectric drive by combining a piezoelectric type MEMS micro-mirror vibration structure and a principle.
First, a driving voltage signal is applied to the piezoelectric driving structure, and the piezoelectric driving structure vibrates in a bending mode due to the inverse piezoelectric effect. The L-shaped elastic beam is connected with the piezoelectric driving structure and the shielding electrode, and converts the vertical displacement of the piezoelectric driving structure into the torsion or vertical displacement of the shielding electrode. Under the control of the piezoelectric driving structure, the comb tooth structure at the tail end of the grounding shielding electrode periodically vibrates in a direction parallel to the direction of an electric field near the comb tooth of the fixed sensing electrode. According to the electric field edge effect, the electric field intensity on the induction electrode changes periodically along with the relative position change of the shielding electrode and the induction electrode. According to the charge induction principle, the surface of the induction electrode can generate periodically changed charges, and the measurement of the electric field to be measured can be realized by detecting the current signal.
The invention aims to provide a piezoelectric drive-based field-mill MEMS electric field sensor, which solves the problems of low precision and low sensitivity of the existing field-mill MEMS electric field sensor.
In order to realize the purpose, the invention provides the following technical scheme: a piezoelectric drive-based field-milling MEMS electric field sensor comprises an SOI substrate, wherein an L-shaped elastic beam, a shielding electrode and a piezoelectric drive structure are arranged on the SOI substrate, the shielding electrode is connected with the piezoelectric drive structure through the L-shaped elastic beam, and the vertical displacement of the piezoelectric drive structure is converted into the torsion or vertical displacement of the shielding electrode; the piezoelectric driving structure controls the modulation mode of the electric sensor: when the applied voltage phase difference of the two side piezoelectric driving structures is 180 degrees, the electric field is in a torsional vibration modulation mode, and when the applied voltage phase difference of the two side piezoelectric driving structures is equal, the electric field is in a piston vibration modulation mode.
The device processing is based on an SOI substrate, the thickness of a top silicon layer of the SOI substrate is the thickness of a silicon substrate of a piezoelectric driving structure designed in advance, the thickness of a buried oxide layer is 100nm-500nm, and the thickness of a silicon layer of the SOI substrate is 400-500 mu m.
The induction electrode is in a one-pair or multi-pair comb tooth shape, the shielding electrode is in a plate-shaped structure, the part of the shielding electrode is in a comb tooth shape, and comb teeth of the induction electrode and the comb tooth electrode are mutually coupled and distributed and are positioned on the same plane. The middle portion of the shielding electrode may be modified to a porous or grid structure to reduce vibration damping.
The piezoelectric driving structure is of a sandwich structure and comprises a top electrode, a piezoelectric material and a bottom electrode layer, and driving voltage is applied to electrode welding spots to control the piezoelectric driving structure. The shape of the piezoelectric driving structure is not limited to the piezoelectric cantilever beam, and comprises a folding beam, an S-shaped beam and a double S-shaped beam.
The L-shaped elastic beam is connected with the piezoelectric driving structure and the shielding electrode, and converts the vertical displacement of the piezoelectric driving structure into the multi-form vibration displacement of the shielding electrode. In order to prevent mechanical damage of the joint during torsional vibration, the joint of the L-shaped elastic beam adopts a rounding structure to enhance the connection stability.
The piezoelectric material used in the middle of the piezoelectric driving structure comprises one or a combination of the following materials: lead zirconate titanate, doped modified lead zirconate titanate, lead magnesium niobate, aluminum nitride and zinc oxide. The piezoelectric material layer can be prepared by a sol-gel method or a magnetron sputtering method.
The metal conductive material selected for the induction electrode and the shielding electrode comprises one or a combination of the following materials: aluminum, platinum, titanium, gold, silver.
Has the beneficial effects that:
(1) the invention skillfully combines the field-grinding type MEMS electric field sensor and the piezoelectric MEMS micro-mirror, effectively improves the resonance frequency of the sensitive structure, enables the field-grinding type MEMS electric field sensor to be capable of modulating at higher frequency, and effectively improves the precision of the sensor.
(2) The MEMS electric field sensor structure has a plurality of modal modulation modes: when the sensor is in a torsional vibration mode, the sensor has high measurement sensitivity; when the sensor is in piston vibration mode, the sensor resonant frequency is high.
(3) Compared with the existing electrostatic-driven torsional MEMS electric field sensor, the sensor driving structure and the sensitive structure are in the same plane, so that only one SOI is needed to be processed during processing, and the MEMS processing difficulty is effectively reduced. The sensor of the invention has simple preparation process and low cost, and is beneficial to batch production.
(4) The sensor has wide application range and can be used in the fields of power grid alternating current and direct current electric field measurement, non-contact voltage measurement, atmospheric electric field detection and the like.
Drawings
FIG. 1 is a schematic structural diagram of a field-milling MEMS electric field sensor based on piezoelectric actuation according to the present invention;
FIG. 2 is a schematic diagram of a piezoelectric drive based field-milled MEMS electric field sensor in a torsional vibration modulation mode according to the present invention;
fig. 3 is a schematic diagram of a piezoelectric drive-based field-milling MEMS electric field sensor in a piston vibration modulation mode.
In the figure, 1-SOI substrate bottom silicon layer, 2-SOI substrate buried oxide layer, 3-SOI substrate top silicon layer, 4-damping balance beam, 5-L-shaped elastic beam, 6-induction electrode, 7-induction electrode welding point, 8-bottom electrode welding point, 9-top electrode welding point, 10-shielding electrode and 11-piezoelectric driving structure.
Detailed Description
The invention will be further described with reference to specific embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functionality throughout.
Example 1
Referring to fig. 1, the invention discloses a piezoelectric drive-based field-milling MEMS electric field sensor, which comprises an SOI substrate and a surface MEMS microstructure required by a flow sheet processing MEMS sensor. The processing substrate selects a customized SOI substrate, which consists of an SOI substrate silicon layer 1, an SOI substrate oxygen-buried layer 2 and an SOI substrate top silicon layer 3, wherein the thickness of the SOI substrate top silicon layer is determined according to the thickness of a silicon layer in a required MEMS microstructure so as to facilitate the processing of suspended and cantilever beam structures. The MEMS microstructure is composed of a piezoelectric driving structure 11, a shielding electrode 10 and an induction electrode 6. The piezoelectric driving structure adopts a piezoelectric cantilever beam structure and can be a single cantilever beam, a folding beam or other deformation structures. The piezoelectric cantilever beam adopts a three-layer sandwich structure, the upper electrode and the lower electrode clamp the piezoelectric material layer, and the upper electrode and the lower electrode apply voltage to form an electric field on the piezoelectric film so as to control the vibration of the piezoelectric driving structure. The middle of the shielding electrode adopts a rectangular plate-shaped structure, the edge part adopts a comb tooth structure, and the middle plate-shaped structure can be changed into a porous or grid structure in order to reduce vibration damping. The induction electrode adopts at least two pairs of comb tooth structures and is fixed on the SOI substrate through a thin beam. The comb teeth part of the sensing electrode and the shielding electrode are coupled and located in the same plane, and the number of the comb teeth of the sensing electrode and the number of the comb teeth of the shielding electrode should be matched. In order to ensure that the electrodes are symmetrically and uniformly distributed, the number of the comb teeth of each induction electrode is larger than or smaller than that of the comb teeth on the single side of the shielding electrode. The shielding electrode is connected with the piezoelectric driving structure through the L-shaped elastic beam 5, and the vertical displacement of the piezoelectric driving structure is converted into the vibration of the shielding electrode. And a silicon microstructure (namely a damping balance beam 4) is utilized at the torsion shaft of the shielding electrode, so that the vibration damping effect of the plate-shaped shielding electrode is adjusted, and the resonance frequency and the quality factor of the MEMS microstructure are improved.
The field mill type MEMS electric field sensor based on piezoelectric drive is based on a charge induction principle, and the principle is similar to that of a traditional field mill, and an alternating current field and a direct current field are measured through modulation. By applying direct current bias and alternating current sine driving voltage signals on the welding spots of the upper and lower driving electrodes reserved outside, the piezoelectric driving structure can be controlled to drive the grounding shielding electrode to vibrate periodically. In order to reduce the loss and increase the output signal of the sensor during operation, the sensor should be operated in a resonant state as much as possible. Therefore, a driving voltage with a corresponding frequency is applied according to the characteristic frequencies of the various vibration modes calculated in advance. When the driving voltages applied to the piezoelectric driving structures on the two sides have the same magnitude and have the phase difference of 180 degrees, the electric field sensor adopts a torsion modulation mode as shown in fig. 2; when the magnitude and phase of the driving voltage signals applied to the piezoelectric driving structures on the two sides are the same, the electric field sensor adopts a piston modulation mode as shown in fig. 3.
When the sensor works, the grounding shielding electrode periodically vibrates, and according to the edge effect of an electric field, the electric field intensity on the sensing electrode is strong when the shielding electrode is near the sensing electrode, and the electric field intensity on the sensing electrode is weak when the shielding electrode is far away from the sensing electrode. According to the Gaussian theorem, a current signal which is in direct proportion to the external electric field intensity can be generated along with the periodic change of the electric field intensity on the induction electrode, and the external electric field can be analyzed and calculated by detecting the reserved current signal on the welding spot 7 of the induction electrode.
Q＝εEA (1)
Wherein Q is the induced charge generated, ε is the dielectric constant, and E is the electric field strength on the induction electrode.
Under vibration modulation, the external electric field is converted into an induced current signal carrying information of the external electric field. If the external electric field signal is a direct current signal, the modulated signal VEDC is an alternating current sinusoidal signal with amplitude proportional to the external electric field, and the frequency is the same as the alternating current part of the driving voltage.
Wherein kq is the charge variation on the induction electrode in unit amplitude of the unit electric field; xr is the amplitude of the shield electrode; e0 is the amplitude of the external electric field to be measured; ω s is the AC drive voltage frequency; phi is the alternating current driving voltage phase; rf is the resistance of the I/V conversion circuit.
If the external electric field signal is an alternating current signal, the modulated signal VEAC is an alternating current mixed signal:
where ω e is the frequency of the external electric field to be measured.
Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present invention, which is defined by the claims appended hereto.
Claims (10)
1. The utility model provides a field mill formula MEMS electric field sensor based on piezoelectricity drive, includes the SOI substrate, be equipped with L type elastic beam (5), shielding electrode (10) and piezoelectricity drive structure (11) on the SOI substrate, its characterized in that: the shielding electrode is connected with the piezoelectric driving structure through the L-shaped elastic beam, and the vertical displacement of the piezoelectric driving structure is converted into the torsion or vertical displacement of the shielding electrode; the piezoelectric driving structure controls the modulation mode of the electric sensor: when the applied voltage phase of the two side piezoelectric driving structures is different by 180 degrees, the electric field is in a torsional vibration modulation mode, and when the applied voltage phase of the two side piezoelectric driving structures is equal, the electric field is in a piston vibration modulation mode.
2. A piezoelectric actuation based field-milled MEMS electric field sensor according to claim 1, wherein: the shielding electrode in the torsional vibration modulation mode takes the central line as an axis to perform back torsional vibration outside the plane; and the whole shielding electrode moves up and down in a mode of modulating the vibration of the piston and is vertical to the plane.
3. A piezoelectric drive based field-milling MEMS electric field sensor as claimed in claim 2, wherein: the piezoelectric driving structure, the induction electrode (6) and the shielding electrode are all positioned on the same plane.
4. A piezoelectric actuation based field-milled MEMS electric field sensor according to claim 3, wherein: the induction electrode is of a comb structure and is fixed on the SOI substrate; the two sides of the shielding electrode are comb structures and are in staggered coupling distribution with the induction electrode on the same plane when the shielding electrode is static.
5. A piezoelectric actuation based field mill type MEMS electric field sensor according to claim 4, characterized in that: the middle of the shielding electrode can be modified into a porous or strip-shaped grid structure for reducing damping.
6. A piezoelectric actuation based field mill type MEMS electric field sensor according to claim 5, characterized in that: the piezoelectric driving structure adopts a piezoelectric cantilever beam structure, and the piezoelectric cantilever beam structure is composed of a single cantilever beam, a folding beam or other deformation structures.
7. A piezoelectric drive based field-milling MEMS electric field sensor as recited in claim 6, wherein: the piezoelectric cantilever beam adopts a three-layer sandwich structure, and the upper electrode and the lower electrode clamp the piezoelectric material layer.
8. A piezoelectric actuation based field mill type MEMS electric field sensor according to claim 7, characterized in that: the material of the piezoelectric material layer comprises one or the combination of the following materials: lead zirconate titanate, doped modified lead zirconate titanate, lead magnesium niobate or aluminum nitride.
9. A piezoelectric actuation based field mill type MEMS electric field sensor according to claim 8, wherein: the metal conducting materials selected for the induction electrode and the shielding electrode comprise one or the combination of the following materials: aluminum, platinum, titanium, gold, or silver.
10. A piezoelectric actuation based field-milling MEMS electric field sensor as claimed in claim 9, wherein: the L-shaped elastic beam joint adopts a rounding structure.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210252347.XA CN114778958A (en) | 2022-03-15 | 2022-03-15 | Piezoelectric drive-based field-grinding type MEMS electric field sensor |
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| CN202210252347.XA CN114778958A (en) | 2022-03-15 | 2022-03-15 | Piezoelectric drive-based field-grinding type MEMS electric field sensor |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115308497A (en) * | 2022-10-12 | 2022-11-08 | 中国矿业大学 | All-solid-state MEMS electric field sensor, preparation method and working method |
| CN115524544A (en) * | 2022-11-24 | 2022-12-27 | 西安交通大学 | Piezoelectric-driven horizontal resonant micro electric field sensor and working method thereof |
| CN115586380A (en) * | 2022-11-03 | 2023-01-10 | 南方电网数字电网研究院有限公司 | Miniature electric field sensor |
| CN115598429A (en) * | 2022-11-23 | 2023-01-13 | 西安交通大学（Cn） | Piezoelectric-driven rotary type miniature electric field sensor and working method thereof |
| CN115980467A (en) * | 2023-03-20 | 2023-04-18 | 西安交通大学 | Piezoelectric driven MEMS type electric field sensor |
| CN116106636A (en) * | 2022-11-17 | 2023-05-12 | 南方电网数字电网研究院有限公司 | Rotary resonance type miniature electric field sensor and electric field measuring device |
| CN116654862A (en) * | 2023-05-18 | 2023-08-29 | 北京科技大学 | Single-chip MEMS three-dimensional electric field sensor with double vibration modes |
-
2022
- 2022-03-15 CN CN202210252347.XA patent/CN114778958A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115308497A (en) * | 2022-10-12 | 2022-11-08 | 中国矿业大学 | All-solid-state MEMS electric field sensor, preparation method and working method |
| CN115308497B (en) * | 2022-10-12 | 2023-01-31 | 中国矿业大学 | All-solid-state MEMS electric field sensor, preparation method and working method |
| CN115586380A (en) * | 2022-11-03 | 2023-01-10 | 南方电网数字电网研究院有限公司 | Miniature electric field sensor |
| CN115586380B (en) * | 2022-11-03 | 2024-01-23 | 南方电网数字电网研究院有限公司 | Miniature electric field sensor |
| CN116106636A (en) * | 2022-11-17 | 2023-05-12 | 南方电网数字电网研究院有限公司 | Rotary resonance type miniature electric field sensor and electric field measuring device |
| CN115598429A (en) * | 2022-11-23 | 2023-01-13 | 西安交通大学（Cn） | Piezoelectric-driven rotary type miniature electric field sensor and working method thereof |
| CN115598429B (en) * | 2022-11-23 | 2023-03-07 | 西安交通大学 | Piezoelectric-driven rotary type miniature electric field sensor and working method thereof |
| CN115524544A (en) * | 2022-11-24 | 2022-12-27 | 西安交通大学 | Piezoelectric-driven horizontal resonant micro electric field sensor and working method thereof |
| CN115980467A (en) * | 2023-03-20 | 2023-04-18 | 西安交通大学 | Piezoelectric driven MEMS type electric field sensor |
| CN116654862A (en) * | 2023-05-18 | 2023-08-29 | 北京科技大学 | Single-chip MEMS three-dimensional electric field sensor with double vibration modes |
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