CN100498343C - Electric tuning resonance differential frequency accelerator - Google Patents

Abstract

A difference frequency accelerometer of electric tuning resonant type is prepared as forming three-stage independent self-oscillation device by semiconductor substrate, external flexible rod, external frame, two-stage flexible rod and two-stage internal frame; causing electric tuning coefficient to be increased to make output frequency of first stage internal frame be decreased and output frequency of second internal frame be increased when upwards acceleration is exerted on external frame; setting FM signal to be related only to frequency without any relation to signal amplitude when downwards acceleration is exerted on external frame.

Description

Electric tuning resonance differential frequency accelerator

Technical field

The invention belongs to microelectronics technology, particularly silicon micro mechanical comb-tooth-type electric tuning resonance differential frequency accelerator.

Background technology

Accelerometer is a kind of sensor commonly used in the detection of machinery, physics and instrument and robotization control.Current, along with the fast development of microelectric technique and micromachining technology, micro-mechanical accelerometer formed product and application in 1993.Initial accelerometer is a force balance type.Employing is made in silicon chip surface micromachined technology, sensitive axes and substrate parallel, and detecting mass is " H " shape.Detecting quality can be freely along moving perpendicular to the direction of beam.Adopting comb structure, each broach is the float electrode or the fixed electorde of variable capacitance, and fixed electorde and float electrode are interconnected.Testing circuit is a bridge solution, applies the carrier signal that frequency is 1HZ on the fixed electorde that detects electric capacity, and the output voltage of accelerometer is directly proportional with the value that detects electric capacity.This output signal is amplified through buffering, and synchronous demodulation feeds back to the capacitor plate of torquer, produces electrostatic force, makes that detecting quality gets back to zero-bit.The entire circuit of accelerometer and microstructure are integrated on a slice silicon chip, with a 5V power supply power supply, sensor output voltage analog quantity.

U.S. AD company had released the twin-axis accelerometer product line in 1998, range from scholar 2g to scholar 100g.As ADxL202 type accelerometer, bandwidth can be by outer electric capacity adjustment.Adopt pulsed modulation to account for and hold specific output, digital output signal directly can enter Computer Processing, or can the converting analogue amount by filtering.

The broach micro mechanical structure is a kind of typical structure of accelerometer now, discloses a kind of resonant acceleration meter with rods (spring) system as U.S. Pat OO5969249A.It is a kind of point of fixity by a mass, the rods system (spring) that connect to support mass, two rods, and the accelerometer formed such as the resonance device of two comb structures.Top (the 1st) resonance device self-oscillation, the increase of rods system affacts the pulling force that makes progress that causes on the mass in acceleration force, bottom (the 2nd) resonance device self-oscillation, the increase of rods system affacts the downward pressure that causes on the mass in acceleration force.This accelerometer is made by micromachined with silicon chip.Resonance device in the accelerometer adopts comb structure, and each broach is the float electrode or the fixed electorde of variable capacitance, and fixed electorde and float electrode are interconnected and form a pair of drive electrode.

Summary of the invention

The present invention's process is to electric tuning principle, comb structure, rods and framework and interconnect isostructural research, a kind of compact conformation is proposed, detection sensitivity and precision are higher, the electric tuning resonance differential frequency accelerator that the output digital signal can directly be connected with digital processing unit.

The present invention just realizes the technical scheme that above-mentioned purpose is taked:

Electric tuning resonance differential frequency accelerator, the external frame that comprises Semiconductor substrate, outside rods, band comb structure, it is characterized in that: the inner frame of two-stage rods, two-stage rods support two-stage band comb structure is externally arranged in the framework, and constitute three grades of independently self-oscillating arrangements by outside rods, external frame structure, two-stage rods and two-stage inner frame; The oscillation frequency difference of two-stage inner frame, be respectively f1 and f2, be subjected to one up or down in the external frame that has electric tuning voltage Vt, promptly do the time spent along the acceleration of coordinate Y direction, area and spacing change between the electric tuning broach, make the electric tuning coefficient change, thereby make one-level inner frame vibration frequency f1 reduce or increase; In like manner, secondary inner frame vibration frequency f2 increases or reduces, and output frequency △ f=f1-f2 changes, and makes the variation of acceleration correspond to the variation of output frequency, detects acceleration magnitude and direction that output frequency has just detected external action like this.

The concrete structure of above-described outside rods, external frame structure, two-stage rods and two-stage inner frame is:

A. four one one-level rods, four secondary rods that an end is connected with the Semiconductor substrate point of fixity that end is connected with the Semiconductor substrate point of fixity, the outside rods that other has four one ends to be connected with the Semiconductor substrate point of fixity;

B. the one-level inner frame that connects of the one-level rods other end, the secondary inner frame that the secondary rods other end connects, and the external frame that is connected with the outside rods other end;

C. support the one-level inner frame by the one-level rods, the secondary rods supports the secondary inner frame, and the two-stage inner frame is parallel to be suspended on the Semiconductor substrate; Outside rods supports outer framework also is suspended on the Semiconductor substrate;

D. the external frame vertical comb teeth that externally has been arranged above and below in the framework, at the two-stage inner frame inner frame vertical comb teeth that has been arranged above and below, it is right that external frame vertical comb teeth and two-stage inner frame vertical comb teeth constitute the electric tuning broach;

E. be arranged with along the horizontal broach of the driving of coordinate X-direction in two-stage inner frame symmetria bilateralis, the horizontal broach of two-stage drive is used for driving the two-stage inner frame respectively; Along the detection level broach of coordinate X-direction, two-stage detection level broach is used for detecting output signal in the two-stage inner frame.

When promptly externally framework is not subjected to vertical direction (along the coordinate Y direction) acceleration, one-level, secondary inner frame can with different frequencies in the horizontal direction (along the coordinate X-direction) do simple harmonic motion, system will export a difference on the frequency of fixing this moment; After external frame is subjected to the downward acceleration of vertical direction (along the coordinate Y-axis in the other direction), staggered area between the vertical comb teeth that structure is arranged above and below changes, spacing between broach also changes, produce the electric tuning effect, thereby make the vibration frequency of one-level inner frame reduce, the vibration frequency of secondary inner frame increases, and the vibration frequency of two-stage inner frame changes makes the difference on the frequency of total output change; Otherwise when being subjected to the acceleration that vertical direction (along the coordinate Y direction) makes progress, situation is opposite.

Electric tuning resonance differential frequency accelerator of the present invention is compared with background technology, though also be that its vibration frequency changed after utilization was subjected to different acceleration,, basic functional principle is different fully.Difference frequency electric tuning resonance accelerometer after the external frame that has electric tuning voltage is subjected to downward acceleration, causes the increase of electric tuning coefficient, causes the output frequency of one-level inner frame to reduce, and the output frequency of secondary inner frame increases; Otherwise, after external frame is subjected to acceleration upwards, the output frequency of one-level inner frame increases, the output frequency of secondary inner frame reduces, FM signal is only relevant with frequency, and is irrelevant with the amplitude of signal, therefore, have stronger antijamming capability, this has great importance for the precision that improves accelerometer.

Electric tuning resonance differential frequency accelerator of the present invention has outstanding advantage and marked improvement:

Has unique electric tuning resonance design, the structural design of high precision resonance type accelerometer;

Has stronger antijamming capability, the high and precision height of detection sensitivity;

The output digital signal can directly be connected with digital processing unit, as computing machine etc.

Framework, rods and detection mass reach compact conformations such as interconnected relationship, and intensity is good, and serviceable life is longer.

Along with the continuous maturation and the development of MEMS micromachined technology in recent years, there has been the resonant mode acceleration transducer that more and more utilizes body silicon process technology and surface treatment to emerge.Believe that in the near future this high performance sensor component can be widely used in many fields such as seismic monitoring, Medical Instruments, Aero-Space, weaponry, has broad application prospects.

Description of drawings

Fig. 1 is the structural representation of electric tuning resonance differential frequency accelerator;

Fig. 2 is the tuning schematic diagram of static;

Fig. 3 is an electric tuning resonance accelerometer mechanical model;

Fig. 4 is the work synoptic diagram of electric tuning resonance differential frequency accelerator;

Fig. 5 is the ANSYS structural drawing of electric tuning resonance accelerometer;

Fig. 6 is the ANSYS static analogous diagram of electric tuning resonance differential frequency accelerator;

Fig. 7 is that the external frame of electric tuning resonance differential frequency accelerator is subjected to the ANSYS analogous diagram that downward acceleration is done the time spent;

Fig. 8 is the inner frame ANSYS structure simulation figure of electric tuning resonance differential frequency accelerator;

When Fig. 9 is the external frame operate as normal (acceleration is zero), the frequency output waveform figure of one-level inner frame;

Figure 10 is an external frame when being subjected to downward acceleration, the frequency output waveform figure of one-level inner frame;

Embodiment

Describe the specific embodiment of the present invention in detail below in conjunction with accompanying drawing.

Shown in Figure 1, electric tuning resonance differential frequency accelerator of the present invention comprises:

A Semiconductor substrate;

Four the one outside rods 8 that end is connected with Semiconductor substrate point of fixity 9 of symmetry are suspended in the supports outer framework on the Semiconductor substrate;

The one-level rods 6 that is connected with Semiconductor substrate point of fixity 1 and the secondary rods 11 of four symmetries, this two-stage rods will support one-level inner frame 5, secondary inner frame 14 is suspended on the Semiconductor substrate;

With the external frame 2 that outside rods 8 other ends are connected, externally be arranged with the broach 15 of vertical direction (along the coordinate Y direction) up and down in the framework;

The two-stage inner frame that is connected with the two-stage rods other end is at the be arranged above and below broach 7 of vertical direction (along the coordinate Y direction) of two-stage inner frame;

The Cui Zhi broach that the internal vertical broach of external frame and two-stage inner frame are arranged above and below constitutes the electric tuning broach to 10;

One-level inner frame and the secondary inner frame that is connected with the two-stage rods other end is arranged with (along the coordinate X-direction) in two-stage inner frame symmetria bilateralis and drives horizontal broach 13 (drive signal loading end 4) respectively, is used for driving the two-stage inner frame respectively; In the two-stage inner frame, be arranged with (along the coordinate X-direction) detection level broach 12 (detection signal exit 3), be used for detecting the frequency signal of two-stage inner frame respectively;

When external frame is not subjected to the vertical direction acceleration, one-level, secondary framework can with different frequencies in the horizontal direction (along the coordinate X-direction) do simple harmonic motion, system will export their difference on the frequency (being a fixed value) this moment.After external frame is subjected to acceleration that vertical direction (along coordinate Y-axis positive dirction) makes progress, external frame is vibration upwards, corresponding area changes between electric tuning this moment broach, make the vibration frequency of one-level inner frame increase, the vibration frequency of secondary inner frame reduces, thereby the output frequency difference of two-stage inner frame increases; Otherwise after being subjected to the downward acceleration of vertical direction (along the coordinate Y-axis in the other direction), situation is opposite.

Arranged an external frame and two inner frames on Semiconductor substrate, three frameworks are self-oscillating arrangement.Symmetric offset spread four outside rods on the external frame, and symmetric offset spread has four rods and is parallel to each other on the one-level inner frame, and symmetric offset spread has four rods also to be parallel to each other on the secondary inner frame.

The above is exactly be made of Semiconductor substrate, outside rods, external frame, two-stage inner flexible bar, two-stage inner frame etc. three grades independently self-oscillating arrangements.Driving comb and detection comb, every pair of broach is that fixed fingers and movable broach are interconnected; The electric tuning broach is made up of the movable broach of two parts, wherein the broach on the external frame only about (along coordinate Y-axis positive dirction) vibration, the broach on the two-stage inner frame only about (along the coordinate X-direction) vibrate.Electric tuning resonance differential frequency accelerator shown in Figure 1, one-level and secondary inner frame are the 180 ° of inverted configuration that turn around, also can be in full accord identical.

The ultimate principle of electric tuning resonance differential frequency accelerator of the present invention:

The principle of work of most of resonance type accelerometers is that after accelerometer was subjected to acceleration upwards, the barycenter of total produced downward displacement, caused the output frequency of accelerometer to increase; Otherwise, after accelerometer is subjected to downward acceleration, to move on the barycenter of structure, this moment, the output frequency of accelerometer reduced.And electric tuning resonance differential frequency accelerator of the present invention adopts the tuning principle of static, different fully with above domestic and international structure working principle, proposed a kind of high-precision static tuned resonance formula accelerometer, FM signal is only relevant with frequency, and is irrelevant with the amplitude of signal.

(1) the tuning principle of static

Fig. 2 is the tuning schematic diagram of static, and upside mass Mass (being external frame) adds certain electric tuning voltage Vt, a plurality of broach is arranged in the above, as shown in the figure.Downside mass (being the two-stage inner frame) with certain frequency side-to-side movement, drives its also side-to-side movement of top broach at the effect lower edge of static driven circuit x direction of principal axis simultaneously, makes that the spacing between the electric tuning broach changes.As can be seen from the figure the initial spacing between broach equates to be x, and charged tuning voltage is a constant on the upside mass, and its size is very big to the influence of the electric tuning coefficient between broach.Under the effect of acceleration g, displacement △ y produces if upside mass (Vt of being with voltage of institute) has up or down at the y direction of principal axis, the axial electrostatic force of x between broach will reduce (or increase), be equivalent to change on the downside mass with the vibration frequency of broach, corresponding to the acceleration of input.

Following according to electric tuning resonance accelerometer mechanical model shown in Figure 3, be analyzed as follows:

For this resonant acceleration meter, when the accekeration that is subjected to when the upside mass was 0, then pairing area A was constant between broach, the side-to-side movement under the effect of static driven power of downside mass, make that the spacing between broach is x, suppose that the spacing between broach is changed to △ x.At this moment, capacitance size is between broach: $c=\mathrm{\&epsiv;}\&CenterDot;\frac{l\&CenterDot;\mathrm{\&omega;}}{x},$ Electrostatic force size then $F_e=\frac{1}{2}\&CenterDot;\frac{\&PartialD;C}{\&PartialD;x}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}^2=-\frac{1}{2}\&CenterDot;\frac{\mathrm{\&epsiv;}\&CenterDot;\mathrm{\&omega;}\&CenterDot;l}{x^2}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}^2=-\frac{1}{2}\&CenterDot;\frac{\mathrm{\&epsiv;}\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="A\; x"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">A</figure-callout>}}{x^{}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}^2.$ Therefore, can obtain by the tuning coefficient of static that this electrostatic force produces according to Hooke's law be: $k=\frac{F_e}{\mathrm{\&Delta;x}}=-\frac{1}{2}\&CenterDot;\frac{\mathrm{\&epsiv;}\&CenterDot;A}{x^3}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}^2,$ Be negative elasticity coefficient.

The size of the tuning coefficient of static is relevant with corresponding area and spacing between broach as can be known by following formula.Therefore, the area or the spacing that change between broach will make the tuning coefficient of static of structure change, thereby make the resonance frequency of downside mass change, and measure the acceleration of input.Above-mentioned formula has illustrated the feasibility of this design philosophy.

(2) principle of work of static tuned resonance formula accelerometer

The resonance differential frequency accelerator is different from the differential capacitive sensor that common sensitization capacitance polar plate spacing changes, and it is to utilize difference between the entire device change frequency to calculate the size of acceleration.This principle of sensing element can utilize the electric tuning principle of broach to analyze.Figure 3 shows that electric tuning resonance accelerometer mechanical model.The downside mass is fixed by left and right sides driving spring, constitutes the self-oscillation structure.

When the upside mass that has constant voltage was subjected to an acceleration that makes progress, the upside mass moved downward.According to the tuning principle of static, area between the electric tuning broach increases, electric tuning elasticity coefficient between broach increases, because the electric tuning coefficient is a negative elasticity coefficient, the driving spring length that is equivalent to the downside mass becomes big, the elasticity coefficient k that can get driving spring reduces, so cause the vibration frequency of downside mass to reduce; Otherwise the vibration frequency of downside mass increases.So, just can judge by the size of measuring acceleration by the frequency change of detection system.Wherein external frame the size of charged tuning voltage Vt the susceptibility of accelerometer g value is had a significant impact.

The electric tuning accelerometer is a kind of to change a kind of acceleration transducer of the electric tuning coefficient between broach.Shown in its structural representation Fig. 3.At first, on the upside mass, apply constant electric tuning voltage+V ₁, the side-to-side vibrations under the effect of static driven power of downside mass.Simultaneously, suppose that downside mass Natural Frequency of Vibration is f ₀When the top mass is subjected to the acceleration of a y axle positive dirction, will vibrate downwards, area corresponding between the electric tuning broach increases, and the tuning coefficient minus of static makes the vibration frequency of downside mass be changed to f to increase ₁Otherwise the vibration frequency of downside mass is changed to f ₂, f then ₁=f ₀+ Δ f, f ₂=f ₀-Δ f

The output frequency of electric tuning formula accelerometer also is the nonlinear function of input acceleration a, general available series expression:

f ₁＝K ₀₁+K ₁₁a+K ₂₁a ²+K ₃₁a ³

f ₂＝K ₀₂-K ₁₂a+K ₂₂a ²-K ₃₂a ³

The difference frequency output of accelerometer:

2 Δ f=f ₁-f ₂=(K ₀₁-K ₀₂)+(K ₁₁+ K ₁₂) a+ (K ₂₁-K ₂₂) a ²+ (K ₃₁+ K ₃₂) a ³Thereby calculate the size of input acceleration.

The course of work of electric tuning resonance differential frequency accelerator of the present invention:

Figure 4 shows that the shop drawing of electric tuning resonance differential frequency accelerator, add ± V at first for the driving comb on the left and right both sides of two-stage inner frame _dBias voltage, to produce electrostatic force this moment between the differential capacitor of microstructure, the driving comb starting of oscillation produces micro displacement, and the broach of the vertical direction up and down of two-stage inner frame (along the coordinate Y direction) also begins vibration, and inner (along the coordinate X-direction) horizontal broach also begins vibration and got up.The tiny signal that produces during the vibration of inner horizontal broach amplifies output by charge amplifier, and the amplifying signal part of output is added on the driving comb on the right, and another part then is added on the driving comb in left side by phase inverter PHD.Like this, the voltage that adds on the driving comb of left and right two ends increases, the amplitude of total system also increases thereupon, and output signal is grow also, and by that analogy, system's amplitude will more and more come greatly, and output signal is also more and more stronger; But because the damping action of external environment, the amplitude of system can undyingly not increase, and will tend towards stability to its vibration afterwards to a certain degree.

Secondly externally apply on the framework+V ₁Constant voltage, make external frame and on the broach of being with have constant voltage.Simultaneously, externally apply certain acceleration on the framework, make external frame vibrate up or down, this result of oscillation makes electric tuning broach spacing area change, because the vibration of inner two-stage framework makes the spacing between the electric tuning broach change, the variation of area and spacing makes the electric tuning coefficient increase or reduces, it is elongated or shorten to be equivalent to the driving spring length of two-stage inner frame, because the electric tuning coefficient is a negative coefficient, the elasticity coefficient k that can get driving spring reduces or increases, and the vibration frequency that causes driving framework changes; Therefore, total system has just produced the difference of frequency.Show that thus the frequency variation of system is relevant with the size of acceleration, the directional correlation of the positive and negative and acceleration of frequency change.So, just can judge by the size and Orientation of measuring acceleration by the frequency change of detection system.

If the voltage on the driving comb of the left and right two ends of two-stage inner frame is respectively+V _d,-V _d, the constant voltage on the external frame is+V ₁, the output signal of left and right two ends charge amplifier is respectively A ₁Sin ω _N1T and A ₂Sin ω _N2T is so added voltage is+V on the broach of the left and right two ends of one-level inner frame _d+ A ₁Sin (ω _N1T+180 ° ,-V _d+ A ₁Sin ω _N1T; Added voltage is+V on the broach of the left and right two ends of secondary inner frame _d+ A ₂Sin (ω _N2T+180 °) ,-V _d+ A ₂Sin ω _N2T; At output terminal the output signal of left and right two parts charge amplifier is multiplied each other:

$(-V_d+A_1\sin {\mathrm{\&omega;}}_{n1}t)*(-V_d+A_2\sin {\mathrm{\&omega;}}_{n2}t)$

$={{\mathrm{<figure-callout\; id="2"\; label="V\; d"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}_d}^2+A_1\sin {\mathrm{\&omega;}}_{n1}\mathrm{<figure-callout\; id="2"\; label="t\; A"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">t</figure-callout>}{A}_{}{}_2\sin {\mathrm{\&omega;}}_{n2}t-{\mathrm{<figure-callout\; id="2"\; label="V\; d\; A"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}_d{A}_{}{}_2\sin {\mathrm{\&omega;}}_{n2}t-{\mathrm{<figure-callout\; id="1"\; label="V\; d\; A"\; filenames="C200710062298E00171.png,C200710062298E00181.png"\; state="\{\{state\}\}">V</figure-callout>}}_d{A}_{}{}_1\sin {\mathrm{\&omega;}}_{n1}t$

$={{\mathrm{<figure-callout\; id="2"\; label="V\; d"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}_d}^2+\frac{1}{2}{A}_1{A}_2[\cos ({\mathrm{\&omega;}}_{n1}-{\mathrm{\&omega;}}_{n2})t-\cos ({\mathrm{\&omega;}}_{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="C200710062298E00171.png,C200710062298E00181.png"\; state="\{\{state\}\}">n</figure-callout>}1}+{\mathrm{\&omega;}}_{n2})t]-{\mathrm{<figure-callout\; id="2"\; label="V\; d\; A"\; filenames="C200710062298E00181.png,C200710062298E00182.png"\; state="\{\{state\}\}">V</figure-callout>}}_d{A}_{}{}_2\sin {\mathrm{\&omega;}}_{n2}t-{\mathrm{<figure-callout\; id="1"\; label="V\; d\; A"\; filenames="C200710062298E00171.png,C200710062298E00181.png"\; state="\{\{state\}\}">V</figure-callout>}}_d{A}_{}{}_1\sin {\mathrm{\&omega;}}_{n1}t$

After bandpass filter, the high and low frequency signal is filtered out, and output signal is just only remaining:

So it is poor that its output signal frequency is exactly two-stage inner frame detection comb output signal frequency.Therefore, just can obtain the size of difference frequency by the wave form varies of output signal.

Electric tuning resonance differential frequency accelerator of the present invention is the tuning accelerometer of a kind of static, utilize the tuning principle of static, adopt the difference frequency structural design, can not only measure the size of input acceleration, and can measure the direction of input acceleration, have very high sensitivity and precision.Fig. 5 has provided the harmonious response analysis of ANSYS static state, mode of electric tuning resonance differential frequency accelerator structure to shown in Figure 10.Simultaneously, utilize the interpretation of result of electrostatic structure coupling Simulation to realize reasonable structural design, realize the linearity test of the accelerometer resonance frequency that the inertia parameter causes.

Claims (4)

1, electric tuning resonance differential frequency accelerator, the external frame that comprises Semiconductor substrate, outside rods, band comb structure, it is characterized in that: the inner frame of two-stage rods, two-stage rods support two-stage band comb structure is externally arranged in the framework, and constitute three grades of independently self-oscillating arrangements by outside rods, external frame structure, two-stage rods and two-stage inner frame; The oscillation frequency difference of two-stage inner frame, be respectively f1 and f2, be subjected to one up or down in the external frame that has electric tuning voltage Vt, promptly do the time spent along the acceleration of coordinate Y direction, area and spacing change between the electric tuning broach, make the electric tuning coefficient change, thereby make one-level inner frame vibration frequency f1 reduce or increase; In like manner, secondary inner frame vibration frequency f2 increases or reduces, and output frequency Δ f=f1-f2 changes, and makes the variation of acceleration correspond to the variation of output frequency, detects acceleration magnitude and direction that output frequency has just detected external action like this.

2, according to the described electric tuning resonance differential frequency accelerator of claim 1, it is characterized in that: described outside rods, external frame structure, two-stage rods and two-stage inner frame are:

A. four one one-level rods (6), four secondary rods (11) that an end is connected with Semiconductor substrate point of fixity (1) that end is connected with Semiconductor substrate point of fixity (1), the outside rods (8) that other has four one ends to be connected with Semiconductor substrate point of fixity (9);

B. the one-level inner frame (5) that connects of one-level rods (6) other end, the secondary inner frame (14) that secondary rods (11) other end connects, and the external frame (2) that is connected with outside rods (8) other end;

C. support one-level inner frame (5) by one-level rods (6), secondary rods (11) supports secondary inner frame (14), and the two-stage inner frame is suspended on the Semiconductor substrate; Outside rods supports outer framework (2) also is suspended on the Semiconductor substrate;

D. externally be arranged with external frame vertical comb teeth (15) in the framework, at the two-stage inner frame inner frame vertical comb teeth (7) that has been arranged above and below, external frame vertical comb teeth and two-stage inner frame vertical comb teeth constitute the electric tuning broach to (10);

E. be arranged with along the horizontal broach of the driving of coordinate X-direction (13) in two-stage inner frame symmetria bilateralis, the horizontal broach of two-stage drive is used for driving the two-stage inner frame respectively; Be arranged with the detection level broach (12) along the coordinate X-direction in the two-stage inner frame, two-stage detection level broach is used for detecting output signal.

3, according to the described electric tuning resonance differential frequency accelerator of claim 1, it is characterized in that: four rods of described connection outside framework are symmetrically distributed, one-level inner frame symmetric offset spread four rods, and the same symmetric offset spread of secondary inner frame four rods.

4, according to the described electric tuning resonance differential frequency accelerator of claim 1, it is characterized in that: described one-level is identical with the structure of secondary inner frame.

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