CN1693901A - High value speedometer - Google Patents

Abstract

The invention discloses a high g acceleration value indicator. The indicator has a beam which is sensitive with acceleration, two circuit boards and a SOI silicon tiny solid pressed chip. On the beam, there is a symmetrical step with these two circuit boards. They are stick symmetrically on the step. The chip in the middle of the beam and it is linked with two boards by leads. The invention adopts the above-mentioned beam whose two ends are fixed steadily and the SOI silicon tiny solid pressed chip to compose a high g acceleration value sensor. It resolves problems about the high g acceleration value measurement in relation to the armour-piercing situation, the bunker invading, the drilling weapon and the aviation bomb directing system, etc. The invention owns characteristics such as high-distance measurement, dynamic research, strong endurance, high accuracy and heavy over loading.

Description

Accelerometer with high g values

Technical field

The invention belongs to the production and the application of acceleration transducer, relate to a kind of accelerometer with high g values based on the SOI technology.

Background technology

When armour-piercing, blindage penetration, brill ground weapon attacking target and bomb were launched, the acceleration information that is produced was to trigger its fuze system arming and ignite one of main reference foundation of initiation system.The development and the weapon continuous advancement in technology of new military thinking, more and more higher to the test request of armament systems acceleration, existing acceleration sensor device can not satisfy the needs of modern war well.For example, in newer versions of these missiles, the rocket attack object procedure, can produce g * 10 ⁵Above acceleration requires the acceleration analysis device can accurately measure this accekeration, and measuring-signal is offered fuze control system; And reach g * 10 at accekeration ⁵During value, accelerometer should have overload protective device, avoids high acceleration shock to cause accelerometer to damage.Existing accelerometer only can bear the following acceleration of 50000g mostly, can not meet the demands.According to the data-searching that the applicant carried out, also there be not the product and the relevant report of accelerometer with high g values at present.

Summary of the invention

The objective of the invention is to, a kind of a kind of accelerometer with high g values based on the SOI technology is provided, this accelerometer integrates stress sensitive and power electricity transition detection, is applicable to the high g value acceleration analysis of fuze systems such as armour-piercing, blindage penetration, brill ground weapon and bomb.

The technical solution that realizes above-mentioned purpose is, a kind of accelerometer with high g values is characterized in that, this accelerometer is made of acceleration sensitive beam, two circuit boards and the little solid-state pressure drag chip of SOI silicon; The step of symmetry is arranged on this acceleration sensitive beam, and there is locating slot at its two ends, and two circuit board symmetries are bonded on the step, and the little solid-state pressure drag chip of SOI silicon is arranged on the centre of acceleration sensitive beam, and the little solid-state pressure drag chip of silicon is connected by lead-in wire with two circuit boards.

The present invention adopts fixing acceleration sensitive beam of both-end and silicon to isolate the high g value of the little solid-state pressure drag chip formation solid-state pressure drag of silicon microstrain of SOI silicon sensor, has solved the high g value acceleration analysis problem of fuze systems such as armour-piercing, blindage penetration, brill ground weapon and bomb.Adopt the eutectic solder technology simultaneously, solved the sluggish problem of sensor.Characteristics such as this acceierometer sensor has the range height, dynamic perfromance is good, weather resisteant is strong and measuring accuracy is high, high overload can satisfy armour-piercing, blindage penetration, bore the measurement needs of the high g value of fuze system acceleration such as ground weapon and bomb.

Description of drawings

Fig. 1 is an accelerometer with high g values scheme of installation of the present invention.

Fig. 2 is an accelerometer with high g values structure composition diagram of the present invention.

Fig. 3 is a flexible member fundamental diagram of the present invention.

Fig. 4 acceleration sensitive girder construction figure.

Fig. 5 is the structural drawing and the micro-photograph of the little solid-state pressure drag chip of SOI silicon.

Fig. 6 is the photo in kind of high g accelerometer.

Be used for armour-piercing, blindage penetration, bore fuze systems such as ground weapon and bomb and be described in further detail below in conjunction with accompanying drawing with below in conjunction with embodiment and the present invention that accompanying drawing and inventor realize with the accelerometer with high g values principle of work.

Embodiment

With reference to Fig. 1, Fig. 2, a kind of accelerometer with high g values is made of acceleration sensitive beam 1, two circuit boards 2,3 and the little solid-state pressure drag chip 4 of SOI silicon; The step that symmetry is arranged on this acceleration sensitive beam 1, there is locating slot at its two ends, two circuit board 2,3 symmetries are bonded on the step, and the little solid-state pressure drag chip 4 of SOI silicon is arranged on the centre of acceleration sensitive beam 1, and the little solid-state pressure drag chip 4 of SOI silicon is connected by lead-in wire 5 with two circuit boards 2,3.

Accelerometer with high g values is connected and fixed by two locating slots and the carrier (fuse assembly) that is on the plane with two gib screws 6, realizes the location of accelerometer.During installation, make the length direction of acceleration direction perpendicular to acceleration sensitive beam 1.

With reference to Fig. 3, when producing diagram perpendicular to the acceleration a of acceleration sensitive beam 1 length direction, the effect that is equivalent on the acceleration sensitive beam, produce distributed force p, according to Newton's law:

p＝ρhwa (1)

In the formula: a is by measuring acceleration, the m/s of unit ²H, w are depth of beam and width, the m of unit; ρ is the density of beam material, unit K g/m ³

Deflection deformation takes place in acceleration sensitive beam 1 under the acceleration effect.Be encapsulated in the variation that the little solid-state pressure drag chip 4 of SOI silicon of acceleration sensitive beam 1 midpoint can sense accelerations sensitive beam 1 stress by eutectic welding, the arm resistance resistance of the Wheatstone bridge in the little solid-state pressure drag chip 4 of SOI silicon is changed pro rata, because:

$\frac{\mathrm{\ΔR}}{R_0}=\frac{\mathrm{\Δ\ρ}}{{\mathrm{\ρ}}_0}=\mathrm{\π\σ}---\left(2\right)$

Electric bridge is exported electric signal under the excitation of fixed power source.The size of the variation of stress and distributed force p is directly proportional, thereby just can predict the size of p by the size of output signal, and through type (1) can calculate by measuring acceleration a.By changing the structural parameters (width, length and thickness) of acceleration sensitive beam 1, can design the accelerometer of different range abilities.

For acceleration transducer, consider the requirement of sensor accuracy index, during design acceleration metering journey, detected strain≤500 μ ε are basis with acceleration sensitive beam 1 SOI of check point place sensitive element, the width of beam is determined by the requirement of pasting silicon pressure drag chip, is calculated the length and the thickness parameter of acceleration sensitive beam according to strain allowable.Volume restrictions when considering encapsulation factor and installation, the structure of the acceleration sensitive beam of design as shown in Figure 4.Under distributed force p effect, the strain maximum that accelerometer elastic beam 1 middle part produces is stress concentration point, and the little solid-state pressure drag chip 4 of SOI silicon is installed in this position, can improve the sensitivity of sensor to greatest extent.

Adopt SOI technology and various silicon micromachining technique on (100) silicon wafer face, to produce the little solid-state pressure drag chip 4 of required SOI silicon.The structure of the little solid-state pressure drag chip 4 of SOI silicon comprises the SiO of 4000 shown in Fig. 5 (a) ₂Be used for isolated measurement circuit layer and silicon base; with LPCVD method extension and be met the monocrystalline silicon layer thickness of piezoresistive effect (about 1.5～2u) and silicon nitride stress matching layer and the protective seam of upper strata 0.1～0.3u, silicon nitride layer wherein is used to eliminate silicon and SiO ₂Influence because of the different thermal stress that cause of thermal expansivity.Resistor stripe adopts four folded structures, relief shape, has the high advantage of detection sensitivity.In order to realize the bonding operation better, the back side of the little solid-state pressure drag chip 4 of SOI silicon has been carried out gold-plated.

Owing to adopted SOI technology and titanium-platinum-golden beam leaded structure, this chip can work under 200 ℃～400 ℃ conditions, has solved the influence that has leakage current under the high temperature, satisfies rugged surroundings downforce Testing requirement such as high temperature.

Adopt the eutectic solder technology the little solid-state pressure drag chip 4 of SOI silicon to be encapsulated in the clamped beam middle part of acceleration flexible member 1.Wherein acceleration flexible member 1 upper surface adopts gold-plated processing, and the solder component of eutectic weldering is 98Au/2Si, under 380 ℃～430 ℃ environmental baseline the little solid-state pressure drag chip 4 of SOI silicon is welded on acceleration flexible member 1 middle part.Eutectic welding has the weld strength height, welds smoothly, and the thermal resistance between little solid-state pressure drag chip 4 of SOI silicon and the acceleration flexible member 1 is little, and has resistance to elevated temperatures.

The microphoto of the little solid-state pressure drag chip 4 of SOI silicon that the inventor finishes by technique scheme as shown in Figure 6.Its overall dimensions: 11mm (L) * 7mm (W) * 1.5mm (H), range: g * 10 ⁵～g * 20 ⁵Sensitivity: 0.5 μ V/g, weight: 0.7 gram.Reached purpose of design through experiment showed.

Claims (3)

1. an accelerometer with high g values is characterized in that, this accelerometer is made of acceleration sensitive beam (1), two circuit boards (2,3) and the little solid-state pressure drag chip of SOI silicon (4); The step that symmetry is arranged on this acceleration sensitive beam (1), there is locating slot at its two ends, two circuit boards (2,3) symmetry is bonded on the step, the little solid-state pressure drag chip of SOI silicon (4) is arranged on the centre of acceleration sensitive beam (1), and the little solid-state pressure drag chip of SOI silicon (4) is connected by lead-in wire (5) with two circuit boards (2,3).

2. accelerometer with high g values as claimed in claim 1 is characterized in that, the little solid-state pressure drag chip of described SOI silicon (4) is bonded together by eutectic welding or other packaging technologies with acceleration sensitive beam (1).

3. accelerometer with high g values as claimed in claim 1 is characterized in that, the back side of the little solid-state pressure drag chip 4 of described described SOI silicon is gold-plated.

Images