CN102928793B - Micromechanical magnetic field sensor and application thereof - Google Patents

Micromechanical magnetic field sensor and application thereof Download PDF

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Publication number
CN102928793B
CN102928793B CN201210470215.0A CN201210470215A CN102928793B CN 102928793 B CN102928793 B CN 102928793B CN 201210470215 A CN201210470215 A CN 201210470215A CN 102928793 B CN102928793 B CN 102928793B
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magnetic field
field sensor
wire coil
micro
resonance oscillator
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CN102928793A (en
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熊斌
吴国强
徐德辉
王跃林
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Shanghai Institute of Microsystem and Information Technology of CAS
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Shanghai Institute of Microsystem and Information Technology of CAS
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Priority to PCT/CN2013/071256 priority patent/WO2014075402A1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/028—Electrodynamic magnetometers
    • G01R33/0286—Electrodynamic magnetometers comprising microelectromechanical systems [MEMS]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/028—Electrodynamic magnetometers

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

The invention provides a micromechanical magnetic field sensor and application thereof. The micromechanical magnetic field sensor at least comprises a resonant oscillator pair, as well as insulating layers and metal wire coils, which are sequentially formed on the surfaces of the resonant oscillator pair. The micromechanical magnetic field sensor utilizes the differential capacitor excitation and electromagnetic induction to measure the size of a magnetic field, two resonant oscillator structures forming the resonant oscillator pair work in anti-phase modes, the metal induction coils on the resonant oscillator structures are wound in the same direction, and induced electromotive forces generated by the metal induction coils on the two resonant oscillator structures are connected in series. As a drive signal is a differential signal, a capacitive coupling signal in an output signal is eliminated to acquire a simplex magnetic field output signal. Meanwhile, the two resonant oscillator structures are coupled through a coupling structure, so that the two resonant oscillator structures act in an integrally connected manner. Further, the micromechanical magnetic field sensor has the advantages of simple structure, less temperature influence, large output signal, high sensitivity, high detection accuracy and suitability for high working frequency.

Description

Micro-mechanical magnetic field sensor and application thereof
Technical field
The invention belongs to micro-mechanical magnetic field sensor design and test technical field, relate to a kind of magnetic field sensor, particularly relate to one be operated in expansion mode under micro-mechanical magnetic field sensor and circuit structure thereof.
Background technology
By inductively signal magnetic field identification direction or be ship navigation, particularly in navigation, space flight, Automated condtrol, military affairs and consumer electronics field, the application of magnetic field sensor is more and more extensive.Magnetic field sensing technology is towards miniaturization, low-power consumption, high sensitivity, high-resolution and and the future development of electronic equipment compatibility.Can be divided into according to operation principle magnetic field sensor: superconductive quantum interference magnetic field sensor, Hall magnetic field sensor, fluxgate magnetometer, giant magnetoresistance magnetic field sensor and induction coil magnetic field sensor.
Superconductive quantum interference magnetic field sensor is the highest in all magnetic field sensor medium sensitivity, but its complex structure, bulky, expensive and need work at low ambient temperatures; Hall magnetic field biosensor power consumption is low, size is little, can measure static state or dynamic magnetic field, but its sensitivity is low, noise level and static shift larger; Fluxgate magnetometer is used for measuring magnetic field that is static or slowly change, and resolution ratio is high, power consumption is little, but volume is comparatively large, frequency response is lower; Giant magnetoresistance magnetic field sensor sensitivity is high, but can not measure large magnetic field; Induction coil magnetic field sensor is the magnetic field carrying out Detect change based on Faraday's electromagnetic induction law, it low in energy consumption, simple (A. L. Herrera-May, L. A. Aguilera-Corts, the P. J. Garca-Ramrez and E. Manjarrez of structure, " Resonant magnetic field sensors based on MEMS technology ", Sensors, vol. 9, no. 10, pp.7785-7813,2009.).
Utilize MEMS(Micro Electro Mechanical system, microelectromechanical systems) the induction coil magnetic field sensor structure of fabrication techniques is simple, be easy to processing, with CMOS IC(Complementary Metal Oxide Semiconductor Integrated Circuit, complementary mos integrated circuit) technique is mutually compatible.MEMS magnetic field sensor has that volume is little, lightweight, low in energy consumption, cost is low, reliability is high, excellent performance and the incomparable advantage of the traditional sensors such as powerful.The development of MEMS technology, makes the micro-structural on chip be processed into possibility, reduces the cost of MEMS simultaneously, but also can complete the task that many large scale Mechatronic Systems can not complete, and this promotes the development of magnetic field sensor.
At present, the magnetic field sensor main operational principle of MEMS structure is: after alive induction coil is subject to the Lorentz force of magnetic fields, the structure of support coils is caused to bend or reverse, measured torsional deflection amount or the bending deformation quantity of support coils structure by capacitance detecting or the method such as piezoresistive detection, optical detection, just can detect the size of field signal.These devices are generally be produced on by induction coil on cantilever beam, U-shaped beam or the flat board that can bend or reverse.During devices function, device is placed in magnetic field, and passes into electric current on induction coil.Induction coil will be subject to Lorentz force, and Lorentz force can cause the bending of cantilever beam, U-shaped beam or flat board or reverse.By measuring the size of cantilever beam, U-shaped beam or plate bending amount or torsional capacity, the size in magnetic field just can be detected.But because these devices function all need to pass into electric current to induction coil, thus their power dissipation ratio is larger; These devices are generally operational in mode of flexural vibration or torsion mode in addition, and thus the resonant frequency of their work is lower.
Further, in order to reduce power consumption and structure complexity, the magnetic field sensor of MEMS structure, can also adopt metal-loaded coil in the resonance oscillator structure that is operated under expansion mode (a kind of situation for body mode) to realize.Described resonance oscillator can be square plate, Circular Plate or circular plate structure.Fig. 1 a to Fig. 1 c is the mode schematic diagram of several resonance oscillator structures being operated in body mode, wherein, dotted line represents the deformation tendency of resonance oscillator structure exterior contour when working (resonant condition), Fig. 1 a is for being operated in the square plate resonance oscillator structure of Square Extensional (SE) mode, Fig. 1 b is for being operated in the circular slab resonance oscillator structure of Radial Extensional (RE) mode, and Fig. 1 c is for being operated in the Circular Plate resonance oscillator structure of Radial Extensional (RE) mode.But the micro-mechanical magnetic field sensor in this magnetic field sensor is quiet electrically driven (operated) device, owing to there is parasitic capacitance between input signal and output port, in the output signal therefore measured, include the capacitive coupling signal caused by capacitive coupling.In prior art, general by reducing parasitic capacitance between input signal and output port, thus reduce capacitively coupled impact.But this method can only reduce capacitive coupling signal, can not be eliminated it completely, in other words, still there is capacitive coupling signal in the output signal, simple magnetic field output signal cannot be obtained.
Summary of the invention
The shortcoming of prior art in view of the above, the object of the present invention is to provide a kind of micro-mechanical magnetic field sensor, and the output signal for solving micro-mechanical magnetic field sensor in prior art cannot eliminate the problem of capacitive coupling effect of signals.
For achieving the above object and other relevant objects, the invention provides a kind of micro-mechanical magnetic field sensor, described micro-mechanical magnetic field sensor at least comprises: resonance oscillator to the insulating barrier be formed at successively on its surface and wire coil; Wherein,
Described resonance oscillator is to comprising:
Two resonance oscillator structures with axially symmetric structure, respectively the symmetry axis of this resonance oscillator structure at least comprises the first symmetry axis and the second symmetry axis, and the first described symmetry axis is perpendicular to the second symmetry axis;
Main brace summer, is positioned on described first symmetry axis, and two resonance oscillator structures to be intercoupled connection by respective main brace summer;
First anchor point, is connected with the free end of described main brace summer, and wherein, the first anchor point of two resonance oscillator structures connects output respectively by the pad be formed thereon or first anchor point connects output and another the first anchor point ground connection;
Drive electrode, be distributed in the opposite side of respectively this resonance oscillator structure respectively, and and be respectively formed between this resonance oscillator structure and drive gap, described drive electrode is connected to dc source by resistance, and described drive electrode is connected to AC power by electric capacity, wherein, respectively the drive electrode of this resonance oscillator structure is connected to the equal AC power of phase place opposite magnitude respectively;
Described insulating barrier is formed at the upper surface of the right resonance oscillator structure of described resonance oscillator and main brace summer, meanwhile, is formed with insulating barrier between described first anchor point and pad formed thereon;
Described wire coil is formed at respectively on the structural insulating barrier of this resonance oscillator respectively, described wire coil be by the described insulating barrier center of its correspondence be top from inside to outside around wire coil, wherein, the structural wire coil of two resonance oscillator be in the same way around; Respectively the top of this wire coil is connected to pad on the first anchor point of its correspondence by the first connecting bridge and respectively the end of this wire coil is interconnected in by the second connecting bridge on the first insulating barrier on the main brace summer that is of coupled connections, or the end of each this wire coil is connected to pad on the first anchor point of its correspondence by the second connecting bridge and respectively the top of this wire coil is interconnected on the first insulating barrier on the main brace summer that is of coupled connections by the first connecting bridge; Respectively this first connecting bridge and be respectively formed with insulating barrier between this wire coil under it.
Optionally, described resonance oscillator is connected to the first coupled beams intercoupled on the described main brace summer of connection and the second anchor point being connected to the described first coupled beams other end to also comprising one end, wherein, the pad ground connection of described second anchor point by being formed thereon, described first coupled beams upper surface and be formed with insulating barrier between described second anchor point and pad formed thereon.
Optionally, the first insulating barrier respectively on the main brace summer and the first coupled beams that are connected through intercoupling by the second connecting bridge of the end of this wire coil is connected to pad on described second anchor point; Or the first insulating barrier respectively on the main brace summer and the first coupled beams that are connected through intercoupling by the first connecting bridge of the top of this wire coil is connected to pad on described second anchor point.
Optionally, described resonance oscillator structure is rectangular slab, circular slab or annular plate.
Optionally, described first coupled beams is vertical pulling beam or bending fold beam.
Optionally, described resonance oscillator, to also comprising the second coupled beams, to be positioned at described in described second coupled beams is also connected on the first symmetry axis and on interconnective main brace summer, and described second coupled beams is connected with the 3rd anchor point; Wherein, described second coupled beams and described first coupled beams are distributed in described first symmetry axis both sides respectively.
Optionally, described second coupled beams is vertical pulling beam or bending fold beam.
Optionally, when described resonance oscillator structure is rectangular slab, described first symmetry axis is parallel to long limit or the broadside of rectangular slab.
Optionally, when described resonance oscillator structure is square plate, described first symmetry axis and the second symmetry axis are respectively the cornerwise extended line of square plate two.
Optionally, described resonance oscillator to be positioned on described second symmetry axis and one end is connected to the other brace summer of described resonance oscillator structure and is connected to the 4th anchor point of the described other brace summer other end also comprising.
Optionally, described wire coil is multilayer, and the described wire coil of each layer is connected mutually, and the described wire coil of each layer have identical around to, be formed with insulating barrier between each layer wire coil.
Optionally, the mode of described wire coil series connection to be connected with the end of wire coil described in odd-level for continuous print even level and continuous print odd-level is connected with the top of wire coil described in even level, and respectively except connecting place, has insulating barrier between this wire coil of mutually connecting.
Optionally, be formed between described wire coil and the insulating barrier under it and support described wire coil and be suspended on metallic support post on described insulating barrier.
Optionally, described wire coil is a circle, and described wire coil is circular or rectangle.
Optionally, described wire coil is multi-turn, and described wire coil is round spiral or rectangular coil shape.
The present invention also provides a kind of circuit structure of micro-mechanical magnetic field sensor, described circuit structure at least comprises: phase-locked loop circuit, differential operational amplifier, described micro-mechanical magnetic field sensor, voltage amplifier and voltage follower, wherein, described phase-locked loop circuit comprises voltage controlled oscillator, phase discriminator and low pass filter;
For generation of the output of the described voltage controlled oscillator of the AC signal identical with described micro-mechanical magnetic field sensor resonant frequency, connect the input of described differential operational amplifier and an input of described phase discriminator respectively, wherein, the AC signal that exports of described voltage controlled oscillator is as the reference signal of described phase discriminator;
AC signal for being exported by described voltage controlled oscillator is converted into the output of the described differential operational amplifier of differential voltage signal, connect the ac power input end of described micro-mechanical magnetic field sensor, the DC supply input of described micro-mechanical magnetic field sensor is also connected with a DC voltage;
Output for generation of the described micro-mechanical magnetic field sensor of induced potential connects the input of described voltage amplifier;
Output for the described voltage amplifier amplified by described induced potential connects another input of described phase discriminator, and wherein, the induced potential signal through amplifying that described voltage amplifier exports is as measuring-signal;
For differentiating that described measuring-signal is connected the input of described low pass filter with the output of the described phase discriminator of phase difference between reference signal;
Output for the described low pass filter of AC portion in phase detector output signal described in filtering connects the control end of described voltage controlled oscillator and the input of described voltage follower, wherein, the direct current signal that described low pass filter exports as the control voltage signal of described voltage controlled oscillator, for ensureing that whole phase-locked loop circuit is in steady-working state;
The output of described voltage follower connects external measurement devices, and wherein, the size of the d. c. voltage signal that described voltage follower exports characterizes the size in described micro-mechanical magnetic field sensor magnetic field to be measured.
Optionally, when the first anchor point of two resonance oscillator structures connects output respectively by the pad be formed thereon, described voltage amplifier is the differential voltage amplifier with two inputs; When first anchor point of two resonance oscillator structures connect output and another the first anchor point ground connection time, described voltage amplifier is the conventional voltage amplifier with an input.
As mentioned above, micro-mechanical magnetic field sensor of the present invention, has following beneficial effect:
1) the present invention adopts coupled beams to get up to form resonance oscillator pair by two resonance oscillator structure Couplings, utilize differential capacitance excitation and electromagnetic induction to measure magnetic field size, wherein, two resonance oscillator arrangement works are in antiphase pattern, respectively the structural wire coil of this resonance oscillator is identical around direction, and the induced electromotive force of two structural wire coil generations of resonance oscillator is connected mutually; Because drive singal is differential signal, then two differential driving signals respectively and form the capacitive coupling signal of two antiphases between output signal, again because these two capacitive coupling signal magnitude are equal, symbol is contrary, therefore the voltage output end that they are recording induced electromotive force can be cancelled out each other, thus the capacitive coupling signal eliminated in output signal, to obtain simple magnetic field output signal, the simple magnetic field output signal achieving micro-mechanical magnetic field sensor detects;
2) the present invention utilizes coupled structure by two resonance oscillator structure Couplings, because coupled structure makes two resonance oscillator anatomical connectivity be integrated motion, thus ensure that whole micro-mechanical magnetic field sensor has single resonant frequency;
3) resonance oscillator of micro-mechanical magnetic field sensor that the present invention proposes is operated in expansion mode, and thus on wire coil, every segment Metal Cutting magnetic induction line generation induced electromotive force can mutual overlapped in series, enhances the intensity of output signal; Wire coil of the present invention can be one or more layers spiral coil, is conducive to the intensity increasing output signal further, improves the sensitivity detected;
4) the present invention can also make wire coil be suspended from described resonance oscillator by metallic support post, thus reduces the problem of the mutual crosstalk of signal between resonance oscillator structure and wire coil at high frequencies;
5) structure of the present invention is simple, does not need to pass into electric current on wire coil, reduces the power consumption of device; Induced electromotive force simultaneously by measuring wire coil two ends measures magnetic field size, and therefore temperature influence is little; And owing to present invention employs two resonance oscillator structures, further enhancing the intensity of output signal, also improve the sensitivity of output signal.
Accompanying drawing explanation
Fig. 1 a to Fig. 1 c is shown as the mode schematic diagram being operated in several resonance oscillator structures of body mode of the prior art, wherein, Fig. 1 a is for being operated in the square plate resonance oscillator structure of Square Extensional (SE) mode, Fig. 1 b is for being operated in the circular slab resonance oscillator structure of Radial Extensional (RE) mode, and Fig. 1 c is for being operated in the Circular Plate resonance oscillator structure of Radial Extensional (RE) mode.
Fig. 2 a is shown as the test circuit schematic diagram of micro-mechanical magnetic field sensor of the present invention in embodiment one, and wherein, described resonance oscillator structure is SE mode square plate.
Fig. 2 b is shown as a kind of test circuit schematic diagram of micro-mechanical magnetic field sensor of the present invention, and wherein, described resonance oscillator structure is SE mode square plate.
Fig. 2 c is shown as the right a kind of dependency structure schematic diagram of micro-mechanical magnetic field sensor resonance oscillator of the present invention.
Fig. 2 d is shown as the right dependency structure schematic diagram of micro-mechanical magnetic field sensor of the present invention its resonance oscillator in embodiment one.
Fig. 2 e is shown as circuit structure schematic diagram in embodiment one of micro-mechanical magnetic field sensor of the present invention.
Fig. 3 a is shown as the test circuit schematic diagram of micro-mechanical magnetic field sensor of the present invention in embodiment two, and wherein, described resonance oscillator structure is Width Extensional (WE) mode rectangular slab.
Fig. 3 b is shown as a kind of test circuit schematic diagram of micro-mechanical magnetic field sensor of the present invention, and wherein, described resonance oscillator structure is WE mode rectangular slab.
Fig. 3 c is shown as the right dependency structure schematic diagram of micro-mechanical magnetic field sensor of the present invention its resonance oscillator in embodiment two.
Fig. 3 d is shown as circuit structure schematic diagram in embodiment two of micro-mechanical magnetic field sensor of the present invention.
Fig. 4 a is shown as the test circuit schematic diagram of micro-mechanical magnetic field sensor of the present invention in embodiment three wherein, and described resonance oscillator structure is RE mode circular slab.
Fig. 4 b is shown as the right dependency structure schematic diagram of micro-mechanical magnetic field sensor of the present invention its resonance oscillator in embodiment three.
Element numbers explanation
1 resonance oscillator structure
21 main brace summers
22 other brace summers
31 first coupled beams
32 second coupled beams
41 first anchor points
42 second anchor points
43 the 3rd anchor points
44 the 4th anchor points
5 drive electrodes
6 insulating barriers
7 wire coils
81 first connecting bridges
82 second connecting bridges
V pdc source
V inaC power
V outvoltage output end
R resistance
C electric capacity
91 voltage controlled oscillators
92 differential operational amplifiers
93 micro-mechanical magnetic field sensor
94 voltage amplifiers
95 phase discriminators
96 low pass filters
97 voltage followers
Detailed description of the invention
By particular specific embodiment, embodiments of the present invention are described below, person skilled in the art scholar the content disclosed by this description can understand other advantages of the present invention and effect easily.
Refer to Fig. 2 a to Fig. 4 b.Notice, structure, ratio, size etc. that this description institute accompanying drawings illustrates, content all only in order to coordinate description to disclose, understand for person skilled in the art scholar and read, and be not used to limit the enforceable qualifications of the present invention, therefore the not technical essential meaning of tool, the adjustment of the modification of any structure, the change of proportionate relationship or size, do not affecting under effect that the present invention can produce and the object that can reach, still all should drop on disclosed technology contents and obtain in the scope that can contain.Simultaneously, quote in this description as " on ", D score, "left", "right", " centre " and " one " etc. term, also only for ease of understanding of describing, and be not used to limit the enforceable scope of the present invention, the change of its relativeness or adjustment, under changing technology contents without essence, when being also considered as the enforceable category of the present invention.
Embodiment one
As shown in Fig. 2 a to 2d, the invention provides a kind of micro-mechanical magnetic field sensor, described micro-mechanical magnetic field sensor at least comprises: resonance oscillator to the insulating barrier 6 be formed at successively on its surface and wire coil 7, wherein, described resonance oscillator is to comprising: resonance oscillator structure 1, main brace summer 21, first anchor point 41 and drive electrode 5.In the present embodiment one, described resonance oscillator is to also comprising the first coupled beams 31 and the second anchor point 42.
Described resonance oscillator structure 1 is two and is axially symmetric structure, and respectively the symmetry axis of this resonance oscillator structure 1 at least comprises the first symmetry axis and the second symmetry axis, and the first described symmetry axis is perpendicular to the second symmetry axis.The material of described resonance oscillator structure 1 is monocrystalline silicon, polysilicon, non-crystalline silicon or carborundum.
It should be noted that, described resonance oscillator structure 1 is rectangular slab, circular slab or annular plate.When described resonance oscillator structure 1 is rectangular slab, described first symmetry axis is parallel to long limit or the broadside of rectangular slab, and preferably, described resonance oscillator structure 1 is square plate; Further, when described resonance oscillator structure 1 is square plate, described first symmetry axis and the second symmetry axis can also be respectively described square plate two cornerwise extended lines
Particularly, in the present embodiment one, as shown in Figure 2 d, two described resonance oscillator structures 1 are monocrystalline silicon square plate, first symmetry axis of square plate resonance oscillator structure 1 and the second symmetry axis are respectively the cornerwise extended line of square plate two, namely main brace summer 21 is connected to the bight of square plate resonance oscillator structure 1, and in Fig. 2 d, respectively the dotted line of this resonance oscillator structure 1 represents the deformation tendency of respectively this resonance oscillator structure 1 exterior contour when working (resonant condition).
Described main brace summer 21 is positioned on described first symmetry axis, and two described resonance oscillator structures 1 to be intercoupled connection by respective main brace summer 21.Particularly, in the present embodiment one, described main brace summer 21 is two, and respectively this monocrystalline silicon square plate resonance oscillator structure 1 to be intercoupled connection by respective main brace summer 21.
It should be noted that, in the present embodiment one, described resonance oscillator to also comprising the first coupled beams 31 and the second anchor point 42, but is not limited to therewith, in another embodiment, described resonance oscillator is to not comprising described first coupled beams 31 and the second anchor point 42(refers to Fig. 2 c).Wherein, one end of described first coupled beams 31 is connected on interconnective described main brace summer 21, and wherein, described first coupled beams 31 is vertical pulling beam or bending fold beam.Particularly, in the present embodiment one, as shown in Figure 2 d, described first coupled beams 31 is bending fold beam.
Described second anchor point 42 is connected to the other end of described first coupled beams 31, and wherein, described second anchor point 42 is formed with pad (intersecting shown in grid as the first anchor point in Fig. 2 a is filled with), and described second anchor point 42 is by described pad ground connection.
Described first anchor point 41 is connected with the free end of described main brace summer 21, wherein, described first anchor point 41 is formed with pad (intersecting shown in grid as the second anchor point in Fig. 2 a is filled with), and the first anchor point 41 of two resonance oscillator structures 1 connects voltage output end V respectively by the pad be formed thereon outor first anchor point meets voltage output end V outand another the first anchor point ground connection, thus by recording this induced electromotive force V outmeasure magnetic field to be measured size.Particularly, in the present embodiment one, as shown in Figure 2 a, the first anchor point 41 of described two resonance oscillator structures 1 connects voltage output end V respectively by the pad be formed thereon out, but be not limited thereto, in another embodiment, the first anchor point 41 of a described resonance oscillator structure 1 meets voltage output end V outand the first anchor point 41 ground connection of another resonance oscillator structure 1, as shown in Figure 2 b.
Described drive electrode 5 is distributed in the opposite side of respectively this resonance oscillator structure 1 respectively, and and respectively this resonance oscillator be formed between tying 1 and drive gap, described drive electrode 5 is connected to dc source V by resistance R p, and described drive electrode 5 is connected to AC power V by electric capacity C in, wherein, the AC power be connected with a resonance oscillator structure 1 is+V in, the AC power be connected with another resonance oscillator structure is-V in, wherein ,+V inwith-V inphase place opposite magnitude is equal, namely respectively the drive electrode 5 of this resonance oscillator structure 1 is connected to the equal AC power of phase place opposite magnitude respectively, to make two resonance oscillator structures, for differential driving mode, (refer to Fig. 2 a), then two resonance oscillator structures 1 are operated in antiphase pattern.Simultaneously, because drive singal is differential signal, then two differential driving signals respectively and form the capacitive coupling signal of two antiphases between output signal, again because these two capacitive coupling signal magnitude are equal, symbol is contrary, and the voltage output end that therefore they are recording induced electromotive force can be cancelled out each other, thus eliminates the capacitive coupling signal in output signal, to obtain simple magnetic field output signal, the simple magnetic field output signal achieving micro-mechanical magnetic field sensor detects.
Preferably, in the present embodiment one, as shown in Figure 2 a, described drive electrode 5 is two opposite sides being positioned at respectively this square plate resonance oscillator structure 1, and be formed between described drive electrode 5 and resonance oscillator structure 1 and drive gap, as shown in Figure 2 d, described drive electrode 5 is two right, and often pair of opposite side being symmetrically distributed in respectively this square plate resonance oscillator structure 1 respectively, namely the often pair of described drive electrode 5 is symmetrically distributed in the limit opposite side of respectively this square plate resonance oscillator structure 1 respectively, but be not limited thereto, described drive electrode can be only a pair in another embodiment, and be distributed in the opposite side of respectively this square plate resonance oscillator structure 1.
It should be noted that, as shown in Figure 2 d, in the present embodiment one, described resonance oscillator is to also comprising the second coupled beams 32, to be positioned at described in described second coupled beams 32 is also connected on the first symmetry axis and on interconnective main brace summer 21, and described second coupled beams 32 is connected with the 3rd anchor point 43, preferably, as shown in Figure 2 d, described second coupled beams 32 is symmetrically distributed in described first symmetry axis both sides with described first coupled beams 31.
What needs further illustrated is, in the present embodiment one, as shown in Fig. 2 a and 2d, described resonance oscillator is to also comprising other brace summer 22 and the 4th anchor point 44, wherein, described other brace summer 22 is positioned on described second symmetry axis, and its one end is connected to resonance oscillator structure 1, its other end is connected to the 4th anchor point 44 ground connection in the 4th anchor point 44(Fig. 2 a, but do not limit to therewith, described ground four anchor points also can be earth-free), namely described other brace summer 22 is connected to the bight of square plate resonance oscillator structure 1, but be not limited to this, in another embodiment, described resonance oscillator is to also not containing described other brace summer and the 4th anchor point.Further, as shown in Figure 2 d, in the present embodiment one, the pad ground connection of shown four anchor points 44 by being located thereon, but be not limited thereto, the pad on shown 4th anchor point also can be earth-free.
Described insulating barrier 6 is formed at the upper surface of the right resonance oscillator structure 1 of described resonance oscillator and main brace summer 21, simultaneously, insulating barrier 6 is formed between described first anchor point 41 and pad formed thereon, particularly, in the present embodiment one, described first coupled beams 31 upper surface is also formed with insulating barrier 6, is formed with insulating barrier 6 between described second anchor point 42 and pad formed thereon.Preferably, described resonance oscillator structure 1, main brace summer 21, first coupled beams 31, first anchor point 41 and the second anchor point 42 are formed in same plane, then described insulating barrier is formed on the upper surface of this plane.Further, in the present embodiment one, described resonance oscillator is to also comprising the second coupled beams 32, 3rd anchor point 43, other brace summer 22 and the 4th anchor point 44, as shown in Figure 2 a, described second coupled beams 32, 3rd anchor point 43 and other brace summer 22 all do not have insulating barrier 6, insulating barrier 6 is formed between described 4th anchor point 44 and the pad be formed thereon, but do not limit to therewith, in another embodiment, described second coupled beams 32, 3rd anchor point 43, other brace summer 22 also can there is insulating barrier 6, on described 4th anchor point 44 during landless, insulating barrier 6 can be there is no yet.
Described wire coil 7 is formed on the insulating barrier 6 in each this resonance oscillator structure 1 respectively, described wire coil 7 be by described insulating barrier 6 center of its correspondence be top from inside to outside around wire coil, wherein, the wire coil 7 in two resonance oscillator structures 1 be in the same way around.Because the wire coil in each this resonance oscillator structure 1 is identical around direction; Again because two resonance oscillator structures 1 are encouraged by differential capacitance, be operated in antiphase pattern, then the induced electromotive force that the wire coil 7 in two resonance oscillator structures 1 produces is connected mutually.
In the present embodiment one, as shown in Figure 2 a, respectively this wire coil 7 be clockwise around, respectively the end of this wire coil 7 is connected to pad on the first anchor point 41 of its correspondence by the second connecting bridge 82 and insulating barrier 6 respectively on the main brace summer 21 and the first coupled beams 31 that are connected through intercoupling by the first connecting bridge 81 of the top of this wire coil 7 is connected to the pad on described second anchor point 42, now, described second connecting bridge 82 is positioned on the insulating barrier 6 on the main brace summer 21 that is connected with the first anchor point 41; Simultaneously, respectively this first connecting bridge 81 and be respectively formed with insulating barrier 6 between this wire coil 7 under it, wherein, described first connecting bridge 81 one end is connected to the top of described wire coil 7 through the insulating barrier 6 be positioned under it, the other end of described first connecting bridge 81 is connected to the pad on the second anchor point 42, now, described first connecting bridge 81 be positioned at wire coil 7, intercouple connect main brace summer 21 and the first coupled beams 31 on insulating barrier 6 on; The material of described wire coil 7, first connecting bridge 81 and the second connecting bridge 82 is gold, but does not limit to therewith, the material of three can identical also can be different, but three be the good electricity of guarantee connects, and the material of three is selected from gold, copper or aluminium.
It should be noted that, the mode of the pad that described wire coil is connected on the first anchor point and the second anchor point is not limited thereto.In another embodiment (not shown), respectively the top of this wire coil is connected to pad on the first anchor point of its correspondence by the first connecting bridge and insulating barrier respectively on the main brace summer and the first coupled beams that are connected through intercoupling by the second connecting bridge of the end of this wire coil is connected to the pad on described second anchor point; Simultaneously, respectively this first connecting bridge and be respectively formed with insulating barrier between this wire coil under it, wherein, described first connecting bridge one end is connected to the top of described wire coil through the insulating barrier be positioned under it, and the other end of described first connecting bridge is connected to the pad on the first anchor point.
It is pointed out that described wire coil also can be able to be multilayer for one deck; When described wire coil is multilayer, the described wire coil of each layer is connected mutually, and the described wire coil of each layer have identical around to, also insulating barrier is formed with between each layer wire coil, wherein, the mode of described wire coil series connection to be connected with the end of wire coil described in odd-level for continuous print even level and continuous print odd-level is connected with the top of wire coil described in even level, with ensure each layer be identical around to, and respectively except connecting place, there is insulating barrier between this wire coil of mutually connecting.Be clockwise around being described for three-layer metal coil: first layer metal coil with center be top from inside to outside clockwise around, second layer metal coil is connected with the end of first layer metal coil, and described second layer metal coil with end ecto-entad clockwise around, now, first layer metal coil and second layer metal coil around to identical, then, third layer wire coil is connected with the top, center of second layer metal coil, and third layer wire coil with center be top from inside to outside clockwise around, now, ground floor, the wire coil of the second layer and third layer around to all identical.
It is further noted that, described wire coil can directly be formed on described insulating barrier, still can be formed between described wire coil and the insulating barrier under it and support described wire coil and be suspended on metallic support post on described insulating barrier, wherein, described support column and coil are same material, are all selected from gold, copper or aluminium.When making wire coil be suspended from described resonance oscillator by metallic support post, the problem of the mutual crosstalk of signal between described resonance oscillator structure and wire coil at high frequencies can be reduced.
It should be noted that, the number of turns of described wire coil is a circle (not closing), and described wire coil is circular or rectangle; Described wire coil also can be multi-turn, and described wire coil is round spiral or rectangular coil shape, but needs to ensure that the shape being positioned at respectively this resonance oscillator structure 1 is consistent with the form trait of the wire coil be located thereon.
Particularly, as shown in Figure 2 a, in the present embodiment one, described wire coil is one deck, is directly formed at square spiral shape wire coil 7 on described insulating barrier 6.
For the embodiment making those skilled in the art understand micro-mechanical magnetic field sensor of the present invention further, specific works step and the operation principle of micro-mechanical magnetic field sensor of the present invention will be described in detail below.Operation principle of the present invention is as follows:
The micro-mechanical magnetic field sensor that the present invention proposes metal-loaded coil in two resonance oscillator structures that formation resonance oscillator is right realizes.The present invention utilizes differential capacitance to encourage driving two resonance oscillator structures to enter resonant condition, when sensor is arranged in tested magnetic field, resonance oscillator vibration can drive wire coil to move, wire coil cutting magnetic induction line, produce induced electromotive force at wire coil two ends, measured the size in tested magnetic field by the induced electromotive force measuring wire coil two ends.
Job step of the present invention is:
A) described micro-mechanical magnetic field sensor is placed in tested magnetic field;
B) apply by dc source V on the drive electrode 5 of micro-mechanical magnetic field sensor simultaneously pwith AC power V inthe superimposed drive singal provided, wherein, the AC power be connected with a resonance oscillator structure 1 is+V in, the AC power be connected with another resonance oscillator structure 1 is-V in, wherein ,+V inwith-V inphase place opposite magnitude is equal, to make two resonance oscillator structures for differential driving mode;
C) when the frequency of the AC signal applied equals the resonant frequency of micro-mechanical magnetic field sensor self, micro-mechanical magnetic field sensor is just in resonant operational state, resonance oscillator vibration drives the wire coil motion be located thereon, wire coil cutting magnetic induction line, now, measure induced electromotive force that wire coil two ends produce thus draw the size in tested magnetic field.
The bright circuit structure that a kind of micro-mechanical magnetic field sensor is also provided of this law, in the present embodiment one, as shown in Figure 2 e, described circuit structure at least comprises: phase-locked loop circuit, differential operational amplifier 92, micro-mechanical magnetic field sensor 93, voltage amplifier 94 and voltage follower 97, wherein, described phase-locked loop circuit comprises voltage controlled oscillator 91, phase discriminator 95 and low pass filter 96.
For generation of the output of the described voltage controlled oscillator 91 of the AC signal identical with described micro-mechanical magnetic field sensor 93 resonant frequency, connect the input of described differential operational amplifier 92 and an input of described phase discriminator 95 respectively, wherein, the AC signal that exports of described voltage controlled oscillator 91 is as the reference signal of described phase discriminator 95.
AC signal for being exported by described voltage controlled oscillator 91 is converted into the output of the described differential operational amplifier 92 of differential voltage signal, connects the ac power input end (+V of described micro-mechanical magnetic field sensor 93 inwith-V in), the DC supply input of described micro-mechanical magnetic field sensor 93 is also connected with a DC voltage V p.
Output for generation of the described micro-mechanical magnetic field sensor 93 of induced potential connects the input of described voltage amplifier 94.
Output for the described voltage amplifier 94 amplified by described induced potential connects another input of described phase discriminator 95, and wherein, the induced potential signal through amplifying that described voltage amplifier 94 exports is as measuring-signal.
For differentiating that described measuring-signal is connected the input of described low pass filter 96 with the output of the described phase discriminator 95 of phase difference between reference signal.
In outputing signal for phase discriminator described in filtering 95, the output of the described low pass filter 96 of AC portion connects the control end of described voltage controlled oscillator 91 and the input of described voltage follower 97, wherein, the direct current signal that described low pass filter 96 exports as the control voltage signal of described voltage controlled oscillator 91, for ensureing that whole phase-locked loop circuit is in steady-working state.
The output of described voltage follower 97 connects external measurement devices (not shown), and wherein, the size of the d. c. voltage signal that described voltage follower 97 exports characterizes the size in described micro-mechanical magnetic field sensor 93 magnetic field to be measured.
The specific works principle of the circuit structure of described micro-mechanical magnetic field sensor is as follows: by the AC signal that voltage controlled oscillator (VCO) 91 generation one in phase-locked loop circuit is identical with micro-mechanical magnetic field sensor 93 resonant frequency; Utilize differential operational amplifier (Single to Differential) 92 that the AC signal that voltage controlled oscillator 91 exports is converted into differential voltage signal, and with DC voltage V pafter superposition, excitation micro-mechanical magnetic field sensor 93 works; The induced potential of micro-mechanical magnetic field sensor 93 is amplified by voltage amplifier (Amplifier) 94; The frequency signal exported by voltage controlled oscillator 91 is as reference frequency, and the output of voltage amplifier 94, as measuring-signal, utilizes the phase difference that phase discriminator 95 is differentiated between measuring-signal and reference signal; By the output signal of phase discriminator 95 access low pass filter (Low-pass Filter) 96, the AC portion in this signal of filtering, obtains the direct current signal relevant to field signal amplitude to be measured; The direct current signal exported by low pass filter 96 as the control voltage signal of voltage controlled oscillator 91, thus ensures that whole phase-locked loop circuit is in steady-working state; The direct current signal of the reflection field signal amplitude to be measured size that low pass filter 96 exports is connected with external measurement devices by voltage follower (Buffer Amplifier) 97, this d. c. voltage signal V finally exported outsize namely characterize the size in described micro-mechanical magnetic field sensor 93 magnetic field to be measured.
Compared with traditional micro-mechanical magnetic field sensor, micro-mechanical magnetic field sensor of the present invention has following beneficial effect:
1) the present invention adopts coupled beams to get up to form resonance oscillator pair by two resonance oscillator structure Couplings, utilize differential capacitance excitation and electromagnetic induction to measure magnetic field size, wherein, two resonance oscillator arrangement works are in antiphase pattern, respectively the structural wire coil of this resonance oscillator is identical around direction, and the induced electromotive force of two structural wire coil generations of resonance oscillator is connected mutually; Because drive singal is differential signal, then two differential driving signals respectively and form the capacitive coupling signal of two antiphases between output signal, again because these two capacitive coupling signal magnitude are equal, symbol is contrary, therefore the voltage output end that they are recording induced electromotive force can be cancelled out each other, thus the capacitive coupling signal eliminated in output signal, to obtain simple magnetic field output signal, the simple magnetic field output signal achieving micro-mechanical magnetic field sensor detects;
2) the present invention utilizes coupled structure by two resonance oscillator structure Couplings, because coupled structure makes two resonance oscillator anatomical connectivity be integrated motion, thus ensure that whole micro-mechanical magnetic field sensor has single resonant frequency;
3) resonance oscillator of micro-mechanical magnetic field sensor that the present invention proposes is operated in expansion mode, and thus on wire coil, every segment Metal Cutting magnetic induction line generation induced electromotive force can mutual overlapped in series, enhances the intensity of output signal; Wire coil of the present invention can be one or more layers spiral coil, is conducive to the intensity increasing output signal further, improves the sensitivity detected;
4) the present invention can also make wire coil be suspended from described resonance oscillator by metallic support post, thus reduces the problem of the mutual crosstalk of signal between resonance oscillator structure and wire coil at high frequencies;
5) structure of the present invention is simple, does not need to pass into electric current on wire coil, reduces the power consumption of device; Induced electromotive force simultaneously by measuring wire coil two ends measures magnetic field size, and therefore temperature influence is little; And owing to present invention employs two resonance oscillator structures, further enhancing the intensity of output signal, also improve the sensitivity of output signal.
Embodiment two
Embodiment two is substantially identical with the technical scheme of embodiment one, and difference is mainly: resonance oscillator structure described in embodiment one is square plate, and described resonance oscillator is to comprising the first coupled beams, the second anchor point, the second coupled beams and the 3rd anchor point; In the present embodiment two, described resonance oscillator structure is rectangular slab, and described resonance oscillator is to not comprising the first coupled beams, the second anchor point, the second coupled beams and the 3rd anchor point, all the other something in common of described resonance oscillator centering (structure, preparation method and operation principle) refer to the associated description of embodiment one, and this is no longer going to repeat them.
As shown in Fig. 3 a and 3c, the present embodiment two provides a kind of micro-mechanical magnetic field sensor, described micro-mechanical magnetic field sensor at least comprises: resonance oscillator to the insulating barrier 6 be formed at successively on its surface and wire coil 7, wherein, described resonance oscillator is to comprising: rectangular slab resonance oscillator structure 1, main brace summer 21, first anchor point 41 and drive electrode 5, but be not limited thereto, in another embodiment, respectively this resonance oscillator centering also can comprise one end and is connected to the first coupled beams on interconnective described main brace summer, be connected to the second anchor point of the other end of described first coupled beams, further, respectively this resonance oscillator centering can also comprise be connected to described in be positioned on the first symmetry axis and the second coupled beams and connect the 3rd anchor point of described second coupled beams on interconnective main brace summer.
Described rectangular slab resonance oscillator structure 1 is carborundum, and its first symmetry axis is parallel to long limit or the broadside of rectangular slab.In the present embodiment two, as shown in Figure 3 c, described first symmetry axis is parallel to the long limit of rectangular slab, and namely main brace summer 21 is connected to the broadside of rectangular slab resonance oscillator structure 1.
Described first anchor point 41 is connected with the free end of described main brace summer 21, wherein, described first anchor point 41 is formed with pad (intersecting shown in grid as the second anchor point in Fig. 3 a and 3b is filled with), and the first anchor point 41 of two resonance oscillator structures 1 connects voltage output end V respectively by the pad be formed thereon out(as shown in Figure 3 a) or one the first anchor point meets voltage output end V outand another the first anchor point ground connection (as shown in Figure 3 b) thus by recording this induced electromotive force V outmeasure magnetic field to be measured size.Particularly, in the present embodiment two, as shown in Figure 3 b, first anchor point 41 of described two resonance oscillator structures 1 meets voltage output end V outand another the first anchor point 41 ground connection.
Described drive electrode 5 is distributed in the opposite side of respectively this rectangular slab resonance oscillator structure 1 respectively, and described drive motors 5 is formed with resonance oscillator structure 1 and drives gap, in the present embodiment two, as shown in Figure 3 b, described drive electrode 5 is two, and be symmetrically distributed in the both sides of the first symmetry axis of respectively this rectangular slab resonance oscillator structure 1, namely described drive electrode 5 is symmetrically distributed in the long limit opposite side of respectively this rectangular slab resonance oscillator structure 1.It should be noted that, in another embodiment, described rectangular slab resonance oscillator structure also can be preferably square plate.
Described insulating barrier 6 is formed at the upper surface of the right resonance oscillator structure 1 of described resonance oscillator and main brace summer 21, meanwhile, is formed with insulating barrier 6 between described first anchor point 41 and pad formed thereon.Preferably, described resonance oscillator structure 1, main brace summer 21 and the first anchor point 41 are formed in same plane, then described insulating barrier is formed on the upper surface of this plane.Further, in another embodiment, when respectively this resonance oscillator centering comprises described second coupled beams 32 and the 3rd anchor point 43, then described second coupled beams 32 and the 3rd anchor point 43 can be formed with insulating barrier 6, also can there is no insulating barrier 6.
The associated description of described wire coil 7 refers to embodiment one, and difference is, the shape of described wire coil 7 is rectangular coil shape, respectively this wire coil 7 be counterclockwise around, as shown in Figure 3 a.
The circuit structure of the micro-mechanical magnetic field sensor of the present embodiment two is substantially identical with embodiment one, and difference is only: the voltage amplifier 94 in embodiment one is for having the differential voltage amplifier of two inputs; And the voltage amplifier 94 of the present embodiment two has the conventional voltage amplifier (referring to Fig. 3 d) of an input; In addition, the present embodiment two is not identical with the structure of the micro-mechanical magnetic field sensor of embodiment one, and all the other something in common refer to the associated description in embodiment one.
Compared with traditional micro-mechanical magnetic field sensor, micro-mechanical magnetic field sensor of the present invention has following beneficial effect:
1) the present invention adopts coupled beams to get up to form resonance oscillator pair by two resonance oscillator structure Couplings, utilize differential capacitance excitation and electromagnetic induction to measure magnetic field size, wherein, two resonance oscillator arrangement works are in antiphase pattern, respectively the structural wire coil of this resonance oscillator is identical around direction, and the induced electromotive force of two structural wire coil generations of resonance oscillator is connected mutually; Because drive singal is differential signal, then two differential driving signals respectively and form the capacitive coupling signal of two antiphases between output signal, again because these two capacitive coupling signal magnitude are equal, symbol is contrary, therefore the voltage output end that they are recording induced electromotive force can be cancelled out each other, thus the capacitive coupling signal eliminated in output signal, to obtain simple magnetic field output signal, the simple magnetic field output signal achieving micro-mechanical magnetic field sensor detects;
2) the present invention utilizes coupled structure by two resonance oscillator structure Couplings, because coupled structure makes two resonance oscillator anatomical connectivity be integrated motion, thus ensure that whole micro-mechanical magnetic field sensor has single resonant frequency;
3) resonance oscillator of micro-mechanical magnetic field sensor that the present invention proposes is operated in expansion mode, and thus on wire coil, every segment Metal Cutting magnetic induction line generation induced electromotive force can mutual overlapped in series, enhances the intensity of output signal; Wire coil of the present invention can be one or more layers spiral coil, is conducive to the intensity increasing output signal further, improves the sensitivity detected;
4) the present invention can also make wire coil be suspended from described resonance oscillator by metallic support post, thus reduces the problem of the mutual crosstalk of signal between resonance oscillator structure and wire coil at high frequencies;
5) structure of the present invention is simple, does not need to pass into electric current on wire coil, reduces the power consumption of device; Induced electromotive force simultaneously by measuring wire coil two ends measures magnetic field size, and therefore temperature influence is little; And owing to present invention employs two resonance oscillator structures, further enhancing the intensity of output signal, also improve the sensitivity of output signal.
Embodiment three
Embodiment three is substantially identical with the technical scheme of embodiment one, and difference is mainly: resonance oscillator structure described in embodiment one is square plate; In the present embodiment three, described resonance oscillator structure is circular slab, and resonance oscillator centering (structure, preparation method and operation principle) remaining something in common refers to the associated description of embodiment one, and this is no longer going to repeat them.
As shown in Figs. 4a and 4b, the present embodiment three provides a kind of micro-mechanical magnetic field sensor, described micro-mechanical magnetic field sensor at least comprises: resonance oscillator to the insulating barrier 6 be formed at successively on its surface and wire coil 7, wherein, described resonance oscillator is to comprising: circular slab resonance oscillator structure 1, main brace summer 21, first coupled beams 31, first anchor point 41, second anchor point 42 and drive electrode 5, wherein, described first symmetry axis is the diameter extended line of circular slab.
It should be noted that, described resonance oscillator structure 1 is not limited to circular slab, described resonance oscillator structure 1 also can be circular slab or Circular Plate, wherein, described first symmetry axis is the major axis of circle or the extended line of minor axis in circular slab or Circular Plate, further, Circular Plate is the preferable case of Circular Plate, and described first symmetry axis is the diameter extended line of Circular Plate.
What needs further illustrated is, as shown in Figure 4 b, described resonance oscillator is to also comprising the second coupled beams 32 be connected on main brace summer 21 and the 3rd anchor point 43 being connected to described second coupled beams 32, wherein, described main brace summer 21 is for being positioned on the first symmetry axis and interconnective main brace summer, but be not limited thereto, in another embodiment, respectively this resonance oscillator centering can not have the second coupled beams yet and is connected to the 3rd anchor point of the second coupled beams.
Described drive electrode 5 is distributed in the opposite side of respectively this square plate resonance oscillator structure 1 respectively, and described drive motors 5 is formed with resonance oscillator structure 1 and drives gap, in the present embodiment three, as shown in Figure 4 b, described drive electrode is two circular arc drive electrodes mated with described circular slab, is symmetrically distributed in the opposite side of respectively this circular slab resonance oscillator structure 1.
Described insulating barrier 6 is formed at the right resonance oscillator structure 1 of described resonance oscillator, main brace summer 21 and the first coupled beams 31 upper surface, simultaneously, be formed with insulating barrier 6 between described first anchor point 41 and pad formed thereon, between described second anchor point 42 and pad formed thereon, be formed with insulating barrier 6.Preferably, described resonance oscillator structure 1, main brace summer 21, first coupled beams 31, first anchor point 41 and the second anchor point 42 are formed in same plane, then described insulating barrier is formed on the upper surface of this plane.Further, in the present embodiment two, described resonance oscillator is to also comprising the second coupled beams 32 be connected on main brace summer 21 and the 3rd anchor point 43 being connected to described second coupled beams 32, as shown in fig. 4 a, described second coupled beams 32 and the 3rd anchor point 43 do not have insulating barrier 6, but do not limit to therewith, in another embodiment, described second coupled beams 32 and the 3rd anchor point 43 also can have insulating barrier 6.
The associated description of described wire coil 7 refers to embodiment one, and difference is, the shape of described wire coil 7 is round spiral, respectively this wire coil 7 be counterclockwise around, as shown in fig. 4 a.
The circuit structure (not shown) of the micro-mechanical magnetic field sensor of the present embodiment three refers to the associated description in embodiment one, and difference is only, the present embodiment three is not identical with the structure of the micro-mechanical magnetic field sensor of embodiment one.
In sum, compared with traditional micro-mechanical magnetic field sensor, micro-mechanical magnetic field sensor of the present invention has following beneficial effect:
1) the present invention adopts coupled beams to get up to form resonance oscillator pair by two resonance oscillator structure Couplings, utilize differential capacitance excitation and electromagnetic induction to measure magnetic field size, wherein, two resonance oscillator arrangement works are in antiphase pattern, respectively the structural wire coil of this resonance oscillator is identical around direction, and the induced electromotive force of two structural wire coil generations of resonance oscillator is connected mutually; Because drive singal is differential signal, then two differential driving signals respectively and form the capacitive coupling signal of two antiphases between output signal, again because these two capacitive coupling signal magnitude are equal, symbol is contrary, therefore the voltage output end that they are recording induced electromotive force can be cancelled out each other, thus the capacitive coupling signal eliminated in output signal, to obtain simple magnetic field output signal, the simple magnetic field output signal achieving micro-mechanical magnetic field sensor detects;
2) the present invention utilizes coupled structure by two resonance oscillator structure Couplings, because coupled structure makes two resonance oscillator anatomical connectivity be integrated motion, thus ensure that whole micro-mechanical magnetic field sensor has single resonant frequency;
3) resonance oscillator of micro-mechanical magnetic field sensor that the present invention proposes is operated in expansion mode, and thus on wire coil, every segment Metal Cutting magnetic induction line generation induced electromotive force can mutual overlapped in series, enhances the intensity of output signal; Wire coil of the present invention can be one or more layers spiral coil, is conducive to the intensity increasing output signal further, improves the sensitivity detected;
4) the present invention can also make wire coil be suspended from described resonance oscillator by metallic support post, thus reduces the problem of the mutual crosstalk of signal between resonance oscillator structure and wire coil at high frequencies;
5) structure of the present invention is simple, does not need to pass into electric current on wire coil, reduces the power consumption of device; Induced electromotive force simultaneously by measuring wire coil two ends measures magnetic field size, and therefore temperature influence is little; And owing to present invention employs two resonance oscillator structures, further enhancing the intensity of output signal, also improve the sensitivity of output signal.
So the present invention effectively overcomes various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.

Claims (17)

1. a micro-mechanical magnetic field sensor, is characterized in that, described micro-mechanical magnetic field sensor at least comprises: resonance oscillator to the insulating barrier be formed at successively on its surface and wire coil; Wherein,
Described resonance oscillator is to comprising:
Two resonance oscillator structures with axially symmetric structure, respectively the symmetry axis of this resonance oscillator structure at least comprises the first symmetry axis and the second symmetry axis, and the first described symmetry axis is perpendicular to the second symmetry axis;
Main brace summer, is positioned on described first symmetry axis, and two resonance oscillator structures to be intercoupled connection by respective main brace summer;
First anchor point, is connected with the free end of described main brace summer, and wherein, the first anchor point of two resonance oscillator structures connects output respectively by the pad be formed thereon or first anchor point connects output and another the first anchor point ground connection;
Drive electrode, be distributed in the opposite side of respectively this resonance oscillator structure respectively, and and be respectively formed between this resonance oscillator structure and drive gap, described drive electrode is connected to dc source by resistance, and described drive electrode is connected to AC power by electric capacity, wherein, respectively the drive electrode of this resonance oscillator structure is connected to the equal AC power of phase place opposite magnitude respectively;
Described insulating barrier is formed at the upper surface of the right resonance oscillator structure of described resonance oscillator and main brace summer, meanwhile, is formed with insulating barrier between described first anchor point and pad formed thereon;
Described wire coil is formed at respectively on the structural insulating barrier of this resonance oscillator respectively, described wire coil be by the described insulating barrier center of its correspondence be top from inside to outside around wire coil, wherein, the structural wire coil of two resonance oscillator be in the same way around; Respectively the top of this wire coil is connected to pad on the first anchor point of its correspondence by the first connecting bridge and respectively the end of this wire coil is interconnected in by the second connecting bridge on the first insulating barrier on the main brace summer that is of coupled connections, or the end of each this wire coil is connected to pad on the first anchor point of its correspondence by the second connecting bridge and respectively the top of this wire coil is interconnected on the first insulating barrier on the main brace summer that is of coupled connections by the first connecting bridge; Respectively this first connecting bridge and be respectively formed with insulating barrier between this wire coil under it.
2. micro-mechanical magnetic field sensor according to claim 1, it is characterized in that: described resonance oscillator is connected to the first coupled beams intercoupled on the described main brace summer of connection and the second anchor point being connected to the described first coupled beams other end to also comprising one end, wherein, the pad ground connection of described second anchor point by being formed thereon, described first coupled beams upper surface and be formed with insulating barrier between described second anchor point and pad formed thereon.
3. micro-mechanical magnetic field sensor according to claim 2, is characterized in that: the first insulating barrier respectively on the main brace summer and the first coupled beams that are connected through intercoupling by the second connecting bridge of the end of this wire coil is connected to pad on described second anchor point; Or the first insulating barrier respectively on the main brace summer and the first coupled beams that are connected through intercoupling by the first connecting bridge of the top of this wire coil is connected to pad on described second anchor point.
4. micro-mechanical magnetic field sensor according to claim 1, is characterized in that: described resonance oscillator structure is rectangular slab, circular slab or annular plate.
5. micro-mechanical magnetic field sensor according to claim 2, is characterized in that: described first coupled beams is vertical pulling beam or bending fold beam.
6. micro-mechanical magnetic field sensor according to claim 2, it is characterized in that: described resonance oscillator is to also comprising the second coupled beams, to be positioned at described in described second coupled beams is also connected on the first symmetry axis and on interconnective main brace summer, and described second coupled beams is connected with the 3rd anchor point; Wherein, described second coupled beams and described first coupled beams are distributed in described first symmetry axis both sides respectively.
7. micro-mechanical magnetic field sensor according to claim 6, is characterized in that: described second coupled beams is vertical pulling beam or bending fold beam.
8. micro-mechanical magnetic field sensor according to claim 4, is characterized in that: when described resonance oscillator structure is rectangular slab, and described first symmetry axis is parallel to long limit or the broadside of rectangular slab.
9. micro-mechanical magnetic field sensor according to claim 4, is characterized in that: when described resonance oscillator structure is square plate, and described first symmetry axis and the second symmetry axis are respectively the cornerwise extended line of square plate two.
10. micro-mechanical magnetic field sensor according to claim 9, is characterized in that: described resonance oscillator to be positioned on described second symmetry axis and one end is connected to the other brace summer of described resonance oscillator structure and is connected to the 4th anchor point of the described other brace summer other end also comprising.
11. micro-mechanical magnetic field sensor according to claim 1, is characterized in that: described wire coil is multilayer, and the described wire coil of each layer is connected mutually, and the described wire coil of each layer have identical around to, be formed with insulating barrier between each layer wire coil.
12. micro-mechanical magnetic field sensor according to claim 11, it is characterized in that: the mode of described wire coil series connection to be connected with the end of wire coil described in odd-level for continuous print even level and continuous print odd-level is connected with the top of wire coil described in even level, and respectively except connecting place, has insulating barrier between this wire coil of mutually connecting.
13. micro-mechanical magnetic field sensor according to claim 1, is characterized in that: be formed between described wire coil and the insulating barrier under it and support described wire coil and be suspended on metallic support post on described insulating barrier.
14. micro-mechanical magnetic field sensor according to claim 1, is characterized in that: described wire coil is a circle, and described wire coil is circular or rectangle.
15. micro-mechanical magnetic field sensor according to claim 1, is characterized in that: described wire coil is multi-turn, and described wire coil is round spiral or rectangular coil shape.
The circuit structure of 16. 1 kinds of micro-mechanical magnetic field sensor, it is characterized in that, described circuit structure at least comprises: phase-locked loop circuit, differential operational amplifier, micro-mechanical magnetic field sensor, voltage amplifier and voltage follower as described in claim 1 to 15 any one, wherein, described phase-locked loop circuit comprises voltage controlled oscillator, phase discriminator and low pass filter;
For generation of the output of the described voltage controlled oscillator of the AC signal identical with described micro-mechanical magnetic field sensor resonant frequency, connect the input of described differential operational amplifier and an input of described phase discriminator respectively, wherein, the AC signal that exports of described voltage controlled oscillator is as the reference signal of described phase discriminator;
AC signal for being exported by described voltage controlled oscillator is converted into the output of the described differential operational amplifier of differential voltage signal, connect the ac power input end of described micro-mechanical magnetic field sensor, the DC supply input of described micro-mechanical magnetic field sensor is also connected with a DC voltage;
Output for generation of the described micro-mechanical magnetic field sensor of induced potential connects the input of described voltage amplifier;
Output for the described voltage amplifier amplified by described induced potential connects another input of described phase discriminator, and wherein, the induced potential signal through amplifying that described voltage amplifier exports is as measuring-signal;
For differentiating that described measuring-signal is connected the input of described low pass filter with the output of the described phase discriminator of phase difference between reference signal;
Output for the described low pass filter of AC portion in phase detector output signal described in filtering connects the control end of described voltage controlled oscillator and the input of described voltage follower, wherein, the direct current signal that described low pass filter exports as the control voltage signal of described voltage controlled oscillator, for ensureing that whole phase-locked loop circuit is in steady-working state;
The output of described voltage follower connects external measurement devices, and wherein, the size of the d. c. voltage signal that described voltage follower exports characterizes the size in described micro-mechanical magnetic field sensor magnetic field to be measured.
The circuit structure of 17. micro-mechanical magnetic field sensor according to claim 16, it is characterized in that: when the first anchor point of two resonance oscillator structures connects output respectively by the pad be formed thereon, described voltage amplifier is the differential voltage amplifier with two inputs; When first anchor point of two resonance oscillator structures connect output and another the first anchor point ground connection time, described voltage amplifier is the conventional voltage amplifier with an input.
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