CN100470214C - Capacitive coseismic vector hydrophone and its process - Google Patents

Abstract

The hydrophone is composed of disk shaped external case with wire guide, silicon micro acceleration sensor inside case, and suspension gear. Using mould, the technique prepares the disk shaped case from admixture of epoxy resin in low density and micro glass bead. Comparing with vectorial hydrophone in other structure, the disclosed hydrophone possesses advantages of small size, lightweight, good directivity, sensitivity of channels and phase characteristics so as to solve issue of designing sonar array. The invention can widely applicable to each area of hydroacoustics such as sonobuoy, navigation for torpedo, submarine communication system to execute low-frequency measurement task.

Description

Capacitive coseismic vector hydrophone and technology thereof

Technical field

The present invention relates to a kind of capacitive coseismic vector hydrophone and technology thereof that adopts silicon micro-acceleration sensor as sensitive element.

Background technology

Generally, the inner vibration transducer that adopts of synchronous vibration type vector hydrophone is as sensitive element, the higher vibration transducer of frequency of utilization mostly is the piezoelectric type principle of work in the Underwater Acoustics Engineering both at home and abroad, and the vector hydrophone diameter of working band below 1kHz of making on this basis is 220mm, weight is 7kg, this vector hydrophone has much advantage when list is only used, and uses the vector hydrophone of this large volume inconvenient in present towing line array sonar, topside battle array sonar, torpedo detection sonar.Along with the development of MEMS technology, succeed in developing at present based on low noise, high sensitivity, the wide band miniature acceleration sensor of MEMS technology, and the beginning commercialization, so MEMS silicon microtechnology has been come into the underwater acoustic transducer field.In such cases, with abundant research vector hydrophone basic theories is prerequisite, adopt silicon micro-acceleration sensor to arise at the historic moment, thereby make development become possibility based on the miniaturization synchronous vibration type vector hydrophone of condenser type principle of work as the synchronous vibration type vector hydrophone of sensitive element.

Still there is not the data of publishing at present both at home and abroad in this regard.

Summary of the invention

The sensor pick up vibration velocity is installed in cylinder can be constituted vector hydrophone water particle vibration velocity sensitivity, therefore play a part extremely crucial in order to indexs such as the sensitivity of the sensor that picks up vibration velocity, volume, weight, working bands to the design of vector hydrophone, in fact, the water particle plane vibration speed measurement can also use acceleration transducer, because have linear relationship between them in the simple harmonic quantity wave field.Utilize modern MEMS technology and ANSYS Software tool, the internal core oscillator (vibration transducer) that influences the vector hydrophone performance index is studied, can obtain having in little, in light weight, the highly sensitive and frequency band below 1kHz of volume the silicon micro-acceleration sensor of flat response, thereby do not reducing under the indicators of overall performance prerequisite of vector hydrophone, its volume, weight are reduced, make vector hydrophone adapt to of the requirement of each field of current Underwater Acoustics Engineering its miniaturization.The invention provides a kind of capacitive coseismic vector hydrophone that adopts silicon micro-acceleration sensor as sensitive element, its volume is little, in light weight, highly sensitive, directive property is good.

The formation of capacitive coseismic vector hydrophone of the present invention is, by placing the inner silicon micro-acceleration sensor [1] of disc shell body [3] that has wire guide [2] to form with four hanging rings [4] that are used for pendulum spring that link to each other with disc shell body [3].This vector hydrophone adopts silicon micro-acceleration sensor [1] to obtain the sound field Vector Message.Because silicon micro-acceleration sensor [1] itself has the characteristic that volume is little, in light weight, cross sensitivity is low, main shaft is highly sensitive, so adopt this technology can guarantee that this invention has good cosine directivity and very high sound pressure sensitivity.

Manufacture craft of the present invention is, the cable [6] and the hanging ring [4] of silicon micro-acceleration sensor [1] and connection thereof are placed the mould [5] that designs in advance, the low-density composite that adopts epoxy resin and glass microballoon to form then carries out embedding and forms disc shell body [3], is moulding after the process oven dry and the demoulding.Silicon micro-acceleration sensor [1] adopts the condenser type principle of work, but its movable plate electrode is for adopting the silicon cantilever of micromachined, this sensor construction is simple, has bigger initial capacitance value, sensor than other type structure has the working band of broad and lower noise, and has overcome other shortcoming that ACTE drift is big, volume is big, mass weight is big.Because gas flow has certain glutinousness in the inner narrow and small cavity of silicon micro-acceleration sensor [1], can regulate the frequency characteristic of the movable system of sensor, reach the purpose that the movable system architecture of expansion Hz-KHz and sensor is optimized.

The disc shell body [3] of this nautical receiving set is that the low-density composite that adopts epoxy resin and glass microballoon to form is made, and the average density of this low-density composite is about 0.65～0.75g/cm ³(epoxy resin of different model is slightly different with the glass microballoon mixture density).Glass microballoon is a kind of material of absolute rigidity, have chemical inertness, proportion is less, and can bear very big pressure after epoxy resin mixes, this potpourri has very high hardness, high mechanical properties, extremely low hydroscopicity and good dielectric property, and can anti-objectionable impurities corrosion.

The theoretical foundation of this nautical receiving set design is: if the physical dimension of the firm cylinder of acoustics is far smaller than wavelength (is kL＜＜1, k is a wave number, L is the maximum linear yardstick of firm cylinder), when then it does free movement under the underwater acoustic wave effect, the vibration velocity amplitude V of cylinder geometric center place water particle in the vibration velocity amplitude V of firm cylinder and the sound field _oBetween have a following relation:

$V=\frac{2{\mathrm{\ρ}}_0}{\stackrel{\‾}{\mathrm{\ρ}}+{\mathrm{\ρ}}_0}{V}_0$

Wherein: ρ ₀---aqueous medium density, the average density of ρ---firm cylinder.

By formula as can be known, equal the aqueous medium density p as the average density ρ of firm cylinder ₀The time, the vibration velocity amplitude V of cylinder geometric center place water particle in its vibration velocity amplitude V and the sound field _oIdentical, like this as long as firm column body has the senser element that can pick up this vibration velocity can obtain the vibration velocity of cylinder geometric center place water particle in the sound field, so require the ensemble average density of this nautical receiving set should be near aqueous medium density, and because its inner vibration-measuring sensor [1] is a metal device, the density of its shell body [3] should be less than aqueous medium density for this reason.

When capacitive coseismic vector hydrophone places under water sound field, under acoustic wave action, this vector hydrophone can be located water particle together with identical amplitude and phase oscillation with its acoustic centre of source, its inner silicon micro-acceleration sensor will produce electric signal output under this vibration signal effect like this, thereby realize the acoustic-electric conversion.

So advantage of the present invention is: nautical receiving set ensemble average density is low (to be about 1.0g/cm ³About), physical dimension little (minimum diameter can reach about 20mm) has cosine directivity preferably.Therefore, not only volume is little, in light weight for this vector hydrophone, directive property is good, and the channel sensitivity height, utilizes the above-mentioned advantage of this nautical receiving set can solve the sonar transducer array design problem.The present invention can be widely used in each field of the underwater sound, as sonar buoy system, low-noise measurement system, bistatic sonar system, torpedo navigational system, underwater communication system, transponder etc., finishes low frequent measuring task.

Description of drawings

Fig. 1 is the capacitive coseismic vector hydrophone cut-open view

Fig. 2 is that capacitive coseismic vector hydrophone is potted in the schematic cross section in the mould

Embodiment

At first, silicon micro-acceleration sensor [1] and four hanging rings [4] are placed the mould [5] of the disc shell body [3] that has wire guide [2], adopt the low-density composite of forming by epoxy resin and glass microballoon to carry out embedding then and form disc shell body [3], at last through oven dry, can form whole nautical receiving set after sloughing mould, the wire guide of its cable output end [2] places on the side end face of shell body [3], also symmetrical respectively [4] 4 of the hanging rings of reserving in the side end face of nautical receiving set shell body [3].Wherein silicon micro-acceleration sensor [1] is selected the CA-DR model for use.This nautical receiving set monolithic case diameter is less than 45mm, and weight is about 100g, and working band is 20Hz～900Hz, and free field voltage sensitivity is-220dB (0dB re 1V/ μ Pa, test frequency 800Hz).

The present invention can be widely used in each field of the underwater sound, as sonar buoy system, low-noise measurement system, bistatic sonar system, torpedo navigational system, underwater communication system, transponder etc., finishes the low frequency measurement task.

Claims (3)

1, a kind of capacitive coseismic vector hydrophone is characterized in that the structure of this nautical receiving set comprises disc shell body [3], silicon micro-acceleration sensor of laying in this disc shell body [3] inside [1] and four hanging rings [4] that are used for pendulum spring that link to each other with disc shell body [3] that have wire guide [2].

2, the manufacture craft of capacitive coseismic vector hydrophone as claimed in claim 1, it is characterized in that placing filling that the disc mould [5] of low-density composite is arranged cable [6] and four hanging rings [4] of silicon micro-acceleration sensor [1] and connection thereof, through after the baking and curing, slough mould [5], obtain to have the nautical receiving set of disc shell [3].

3, the manufacture craft of capacitive coseismic vector hydrophone as claimed in claim 2, the disc shell [3] that it is characterized in that this nautical receiving set is that the low-density composite that adopts epoxy resin and glass microballoon to form is made, and the average density of this low-density composite is 0.65-0.75g/cm ³

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