CN105277187A - Design method of anti-vibration circuit board used for silicon microgyroscope - Google Patents

Abstract

The invention discloses a design method of an anti-vibration circuit board used for a silicon microgyroscope. A gyroscope chip is mounted on a circuit board to obtain a whole body and then the whole body is fixedly mounted in a gyroscope metal shell; by increasing the thickness of the circuit board and reducing the equivalent distance, relative to the gyroscope chip, of a fixed connection piece between the circuit board and the shell, the inherent frequency of the circuit board is improved, and the low-frequency environment vibration resisting property of the silicon microgyroscope is realized. With the adoption of the method provided by the invention, a completed gyroscope sensitive structure and a detection circuit do not need to be modified, and a product can be obtained by only improving the circuit board of the silicon microgyroscope; the design method has the advantages of low cost and short research period; and meanwhile, the size, weight and cost of the silicon microgyroscope are not remarkably increased when the method is adopted and the method is easy to realize.

Description

A kind of anti-vibration circuit board designing method for silicon micro-gyroscope

Technical field

The present invention relates to electronic applications, be specifically related to a kind of anti-vibration circuit board designing method for silicon micro-gyroscope.

Background technology

Silicon micro-gyroscope has the advantages that volume is little, quality is light, cheap, can be widely used in the numerous areas such as consumer electronics product, industry spot, vehicle detection.

Silicon micro-gyroscope includes movable mass, its by Coriolis effect (Corioliseffect) measure detection axis to angular velocity signal.When detection axis is to when existing input angular velocity signal, movable mass upwards will produce resonance in sensitive axes, change, instead can infer and calculating input angular velocity signal by detecting spacing between movable mass and fixing microstructure.

Usual silicon micro-gyroscope instrument chip is installed on circuit board (PCB), and then integral installation is fixed in gyroscope shell.Circuit board realizes chip and extraneous electrical connection, also plays the effect of fixing GYROCHIP, for it provides reliable mechanical connection simultaneously.

But being fixed on circuit board due to silicon micro-gyroscope instrument chip, circuit board is connected with testee by shell.Mechanical vibration on testee all will be passed on the movable mass of GYROCHIP.Therefore external environment vibration also will cause the movable quality of gyro to be vibrated, and then cause responsive Detection capacitance capacitance in gyroscope to change, and produce error signal.

The random vibration frequency of external environment is generally within the scope of 2kHz, and silicon micro-gyroscope interior circuit board size is about centimetres, and circuit board natural vibration frequency is close or be positioned at environment low frequency random vibration frequency range.Circuit board can amplify external environment vibration, forms resonance.Therefore need the natural vibration frequency improving circuit board, make it the low frequency random vibration frequency range far above 2kHz.

Volume is little, quality is light, cheap be that silicon micro-gyroscope is compared with the gyrostatic advantage of other types.Although employing vibration isolator can reduce even to eliminate the impact of ambient vibration on silicon micro-gyroscope performance, the shortcoming that it exists, and volume is large, quality is heavy, does not meet the requirement of silicon micro-gyroscope application scenario.

Patent of invention " vibration damping and hot shielding system for surface mount vibration sensing device " proposes between circuit board and surface mount device, place the elastomeric material with conductive fiber material.Its elastomeric material proposed allows signal and electric current flow between surface mount device and circuit board and do not use electric wire or the wire of any attachment, and meanwhile elastomeric material reduces the vibration being delivered to paster apparatus.Although the method that this invention proposes achieves the vibration damping of surface mount device and heat insulation, but the inapplicable silicon micro-gyroscope of the method, its reason is according to the method, then elastomeric material can reduce the support stiffness of gyroscope chip, and then the natural resonance frequency of gyroscope and circuit board total system can be reduced further, gyro will be more severe by the impact of low frequency random vibration.

Utility model patent " a kind of controller PCB plate pad vibration-proof structure " proposes a kind of PCB vibration-proof structure, and its Design PCB four angles are all sandwiched between upper and lower casing by upper and lower two-layer pad, and positioned by corresponding screw, bolt carries out fastening.This structure is simple, and be easy to assembling, cost is low, can bear multiaxis loading, absorbs and impacts and dither.But this oscillation damping method reduces the overall natural resonance frequency of circuit board systems, and therefore the method is not suitable for the low frequency vibration damping of silicon micro-gyroscope.

Patent of invention " a kind of vibratory impulse compound sensor improving low frequency characteristic " proposes to be connected with machine high rigidity butt coupling with by the Low rigidity of flexible PCB to sensor internal resonating device and cable by sensor base, and the sensor internal that solves sensor base less than to be connected with machine high rigidity has the frequency response problem caused by higher stiffness due to stube cable.But the method is mainly for track traffic, the required vibration transducer of field of wind power generation fault diagnosis, be not easily applied in the microsensor of volume (being generally tens cubic centimetres or less) and weight (within being generally three hectograms) requirement harshness.And the LF-response that the method realizes only reaches hundreds of hertz, the requirement of random vibration within the anti-2kHz of silicon micro-gyroscope can not be met.

Summary of the invention

In order to solve the technical matters existed in prior art, this patent provides a kind of anti-vibration circuit board designing method for silicon micro-gyroscope.

Due in reality use, there is inevitable random vibration in external environment, random vibration frequency is generally within the scope of 2kHz, and the circuit board size for installing silicon micro-gyroscope instrument chip is about centimetres, circuit board natural vibration frequency is close or be positioned at low frequency environments random vibration frequency range, circuit board can amplify external environment vibration, forms resonance.Therefore need to take appropriate measures, reduce or eliminate ambient vibration to the impact of silicon micro-gyroscope.

The advantage of silicon micro-gyroscope compared with other types gyroscope be that volume is little, quality is light, cheap, can be mass-produced, therefore the vibration reducing measure of silicon micro-gyroscope needs to possess the volume, weight, the cost that significantly do not increase silicon micro-gyroscope, and is easy to the feature of realization.

All silicon micro-gyroscope vibration damping can be realized by different technologies approach.Improve the design of silicon micro-gyroscope sensitive structure, as improved sensitive structure natural frequency, sensitive structure differential mode exports; Optimize silicon micro-gyroscope circuit design, as increased wave filter; Improve silicon micro-gyroscope encapsulation and assembling mode, as adopted vibration damping assembly structure.These methods all can reduction Environmental Random Vibration in various degree on gyrostatic impact.

Improve gyroscope sensitive structure and testing circuit increase filter design, all need to re-start gyroscope sensitive structure and measurement circuit design, simulation calculation, and again process, cause design cycle and R&D costs significantly to improve.And improve silicon micro-gyroscope assembling mode, not needing to revise completed gyroscope sensitive structure and testing circuit, can realize silicon micro-gyroscope vibration damping by means of only improvement silicon micro-gyroscope circuit board, is a kind of simple, effective method.

The technical solution used in the present invention is:

A kind of anti-vibration circuit board designing method for silicon micro-gyroscope, GYROCHIP is installed on circuit board, and then entirety is fixedly installed in gyroscope metal shell, it is characterized in that, by increasing the thickness of circuit board and reducing fixed connecting piece between circuit board and shell and, relative to the equivalent distances of GYROCHIP, improve circuit board natural frequency.

Adopt mass-spring-damper lumped parameter model to come to be connected and fixed mode in approximate silicon micro-gyroscope between GYROCHIP, circuit board, shell, circuit board is equivalent to three parts, m _pcb1and m _pcb3for circuit board anchors to the equivalent mass of gyroscope shell, m _pcb2for connecting the equivalent electrical circuit plate quality of GYROCHIP;

Due to board quality m _pcbbe proportional to circuit board thickness h, namely

m _pcb∝h

If circuit board is equivalent to the thin-slab construction that surrounding is fixing, its rigidity k _pcbbe proportional to the cube of circuit board thickness h, namely

k _pcb∝h ³

Therefore circuit board natural frequency f _pcbbe similar to and be proportional to circuit board thickness,

$f_{pcb}=\frac{1}{2\mathrm{\π}}\sqrt{\frac{k_{pcb}}{m_{pcb}}}\∝\sqrt{\frac{h^3}{h}}=h$

So improve circuit board natural frequency f by increasing circuit board thickness h _pcb.

Through the connecting hole on circuit board, circuit board is fixed in gyroscope metal shell by web member; Circuit board is equivalent in the fixing thin-slab construction model of surrounding, circuit board rigidity k _pcbreduce with thin plate radius r and increase, therefore circuit board natural frequency f _pcbreduce with thin plate radius r and increase.

So relative to the equivalent distances r of GYROCHIP, circuit board natural frequency f can be improved by reducing fixed connecting piece between circuit board and shell _pcb.

The beneficial effect that the present invention reaches:

The method adopting this patent to propose, does not need to revise completed gyroscope sensitive structure and testing circuit, can realize, have the advantage that cost is low, the lead time is short by means of only improvement silicon micro-gyroscope circuit board.The method does not significantly increase volume, weight, the cost of silicon micro-gyroscope simultaneously, and is easy to realize.

Accompanying drawing explanation

Fig. 1 is silicon micro-gyroscope assembly structure schematic top plan view.

Fig. 2 is silicon micro-gyroscope assembly structure cut-open view schematic diagram.

Fig. 3 is silicon micro-gyroscope assembly structure spring-damper-mass lumped parameter equivalent model.

Fig. 4 is the gyroscope assembly structure cut-open view schematic diagram increasing circuit board thickness.

Fig. 5 is the gyroscope assembly structure schematic top plan view of Circuit tuning plate fixed position.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.

The assembling of usual silicon micro-gyroscope is installed on circuit board 2 by GYROCHIP 1, and then entirety is fixedly installed in gyroscope metal shell 3, fixed, as shown in Figure 1 and Figure 2 by gib screw 4.

Circuit board 2 size of installing silicon micro-gyroscope instrument chip 1 and chip periphery capacitance-resistance chip 5 is about centimetres, and circuit board 2 natural vibration frequency is close or be positioned at low frequency environments random vibration frequency range, and circuit board can amplify external environment vibration.Therefore the natural frequency improving circuit board is needed.

Mass-spring-damper lumped parameter model can be adopted to be connected and fixed mode in approximate silicon micro-gyroscope between GYROCHIP, circuit board, shell, as shown in Figure 3.Because the Young modulus of circuit board is less, comparatively other parts are easy to deformation occurs, and therefore circuit board are equivalent to three parts, m _pcb1and m _pcb3for circuit board anchors to the equivalent mass of gyroscope shell, m _pcb2for connecting the equivalent electrical circuit plate quality of GYROCHIP.K _pcb2for circuit board is connected to the equivalent stiffness of GYROCHIP, it is less than the equivalent stiffness k that circuit board anchors to gyroscope shell _pcb1and k _pcb3.

This patent proposes a kind of simple, effective method suppressing extraneous environmental noise by improving circuit board natural frequency.By increasing circuit board 2 thickness, the position of the screw 41 of the gib screw 4 simultaneously Circuit tuning plate 2 installed, can realize improving circuit board natural frequency, make system frequency that GYROCHIP 1, circuit board 2, shell 3 form far above 2kHz, and then reach the object reducing external environment random vibration and gyro output signals is disturbed, as shown in Figure 4.Due to board quality m _pcbbe proportional to circuit board thickness h, namely

m _pcb∝h

If circuit board is equivalent to the thin-slab construction that surrounding is fixing, its rigidity k _pcbbe proportional to the cube of circuit board thickness h, namely

k _pcb∝h ³

Therefore circuit board natural frequency f _pcbcan be similar to and be proportional to circuit board thickness,

$f_{pcb}=\frac{1}{2\mathrm{\π}}\sqrt{\frac{k_{pcb}}{m_{pcb}}}\∝\sqrt{\frac{h^3}{h}}=h$

Therefore increase circuit board thickness h can improve circuit board natural frequency f _pcb.

By and reduce fixed connecting piece between circuit board and shell and, relative to the equivalent distances of GYROCHIP, further can improve the natural frequency of circuit board.

Fig. 5 is a kind of schematic diagram of Circuit tuning plate fixed position, screw 41 position circuit board 2 being fixed to shell 3 is by after near the mid point adjusting to each limit of circuit board near four drift angles of circuit board, from the angle of GYROCHIP, the thin plate radius of circuit board equivalence reduces, therefore the resonance frequency of circuit board can be further improved, and then more higher than the low frequency random vibration frequency of 2kHz.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.

Claims (4)

1. the anti-vibration circuit board designing method for silicon micro-gyroscope, GYROCHIP is installed on circuit board, and then entirety is fixedly installed in gyroscope metal shell, it is characterized in that, by increasing the thickness of circuit board and reducing fixed connecting piece between circuit board and shell and, relative to the equivalent distances of GYROCHIP, improve circuit board natural frequency.

2. a kind of anti-vibration circuit board designing method for silicon micro-gyroscope according to claim 1, is characterized in that,

Adopt mass-spring-damper lumped parameter model to come to be connected and fixed mode in approximate silicon micro-gyroscope between GYROCHIP, circuit board, shell, circuit board is equivalent to three parts, m _pcb1and m _pcb3for circuit board anchors to the equivalent mass of gyroscope shell, m _pcb2for connecting the equivalent electrical circuit plate quality of GYROCHIP;

Due to board quality m _pcbbe proportional to circuit board thickness h, namely

m _pcb∝h

If circuit board is equivalent to the thin-slab construction that surrounding is fixing, its rigidity k _pcbbe proportional to the cube of circuit board thickness h, namely

k _pcb∝h ³

Therefore circuit board natural frequency f _pcbbe similar to and be proportional to circuit board thickness,

$f_{pcb}=\frac{1}{2\mathrm{\π}}\sqrt{\frac{k_{pcb}}{m_{pcb}}}\∝\sqrt{\frac{h^3}{h}}=h$

So circuit board natural frequency f can be improved by increasing circuit board thickness h _pcb.

3. a kind of anti-vibration circuit board designing method for silicon micro-gyroscope according to claim 1 and 2, is characterized in that, relative to the equivalent distances r of GYROCHIP, improves circuit board natural frequency f by reducing fixed connecting piece between circuit board and shell _pcb.

4. a kind of anti-vibration circuit board designing method for silicon micro-gyroscope according to claim 3, is characterized in that,

Through the connecting hole on circuit board, circuit board is fixed in gyroscope metal shell by web member;

Described connecting hole is arranged on the midpoint on each limit of circuit board.