JP2567872Y2 - Receiver - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for converting underwater sound waves into an electric signal, and more particularly to a small receiver in which an electronic circuit is housed.

[0002]

2. Description of the Related Art A conventional receiver generally has a structure using a bolted Langevin vibrator in which piezoelectric vibrators are stacked, a structure using a cylindrical piezoelectric vibrator, a structure using a flat plate piezoelectric vibrator, and the like. It is used. A cylindrical piezoelectric vibrator or a flat-plate type piezoelectric vibrator is used in a wave receiver aiming at miniaturization and weight reduction. In particular, as shown in FIG. 4, a metal plate 10 and a flat-plate-shaped piezoelectric vibrator 4 are bonded together. Often a bimorph or unimorph structure is used.

FIG. 3 shows an example of the structure of a small receiver using the unimorph structure. The sound receiving portion 8 has a unimorph or bimorph structure, and the sound receiving portion is attached to the substrate 9.
After the sound signal is converted into an electric signal by the sound receiving unit, the signal is amplified by the electronic circuit 6 on the board and transmitted by the cable 7.

[0004]

Since the conventional receiver uses a bimorph or unimorph structure,
There is a problem that it cannot be used under a deep water pressure. When high water pressure is applied, it is necessary to make the metal plate thicker or reduce its diameter in order to prevent the sound receiving part from crushing.However, this reduces the amount of deflection and reduces the receiving sensitivity, that is, the electric signal from underwater sound waves. Conversion efficiency is reduced. In addition, when the diameter is reduced, there is no space for accommodating the electronic circuit, and the electronic components are mounted on the board outside the sound receiving portion.However, stress due to water pressure is directly applied to the electronic components, and the reliability of the electronic components is reduced. There has been a problem that it is significantly reduced.

Further, there is a problem that a noise output is large when vibration is applied to the receiver.

An object of the present invention is to provide a small, lightweight, and highly reliable receiver that can be used at a great depth.

[0007]

Receivers of the present invention SUMMARY OF THE INVENTION may, an annular piezoelectric transducer which converts an electrical signal to mechanical vibration to both surfaces of the neutral plate is provided, further piezoelectric against neutral plate A pressure receiving plate for converting sound waves into mechanical vibration is provided outside the vibrator, and a cable for signal transmission and power supply is connected to the neutral plate, and the center of the ring of the annular piezoelectric vibrator is connected to the neutral plate. versus
Then, an electronic circuit for amplifying electric signals is provided on the inner neutral plate surface.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1A is a perspective view of an embodiment of the receiver according to the present invention, FIG.
FIG. 1B is a sectional view taken along line AA ′ of FIG. 1A, and FIG. 2 is an explanatory view showing an internal structure.

As shown in FIGS. 1 and 2, an annular piezoelectric vibrator 1 is provided on both sides of a neutral plate 5, and a pressure receiving plate 2 is provided outside the piezoelectric vibrator with respect to the neutral plate. Is provided.
A cable 7 is connected to the neutral plate, and an electronic circuit 6 is provided on the surface of the neutral plate inside the center of the ring of the ring- shaped piezoelectric vibrator.

Next, the operation of the receiver according to the present invention will be described. Since sound waves propagating in water are compression waves, when the receiver is sufficiently smaller than the wavelength of the sound waves, a pressure proportional to the sound pressure is applied to the pressure receiving plate from the outside. The force applied to the pressure receiving plate is applied to the annular piezoelectric vibrator, converted into an electric signal, amplified by an electronic circuit, and transmitted by a cable.

The pressure receiving plate has a disk-like shape made of a metal or a synthetic resin, and has a curved surface to increase the strength in order to increase the water pressure resistance. When the water pressure is not so much applied, a flat plate may be used.

The ring-shaped piezoelectric vibrator has a structure using electrodes on upper and lower surfaces or inner and outer surfaces, receives a pressure generated by a sound wave received by a pressure receiving plate, and converts the pressure into an electric signal by a piezoelectric effect. Here, the wave receiving sensitivity is determined by the thickness between the electrodes of the ring-shaped piezoelectric vibrator and the stress amplification by the area ratio between the pressure receiving plate and the ring-shaped piezoelectric vibrator, and is not related to the size of the wave receiver. The stress generated by water pressure is also applied to the piezoelectric vibrator by multiplying it by the stress amplification factor. However, since the allowable compressive stress of the piezoelectric vibrator is generally about 4000 kg / cm ² , the stress amplification factor is about 10 times. Even when used, it can be used at a water pressure of 400 kg / cm ² , that is, a water depth up to 4000 m.

The neutral plate has an annular piezoelectric vibrator adhered and held on both surfaces, and is provided at the center of the annular ring of the annular piezoelectric vibrator.
On the inside surface, an electronic circuit such as a preamplifier circuit is provided. The signal output of the electronic circuit or the power supply to the electronic circuit is performed by connecting to a cable outside the annular piezoelectric vibrator by printed wiring on the surface of the neutral plate or internal wiring using a multilayer substrate.

The cable is a multi-core cable for power supply and signal transmission, and a tension member is fixed to a neutral plate.
Only the conductor is connected to the neutral plate wiring.

The whole is kept waterproof by a resin mold or coating.

Further, noise generated due to vibration or the like is reduced by providing a piezoelectric vibrator or a pressure receiving plate symmetrically with respect to the neutral plate. Vibration in the plane including the cable and the receiver causes a displacement deformation in which the pressure receiving plate becomes a mass, but the piezoelectric effect is small for such a deformation, and almost no electric output appears. Also, the vibration in the direction perpendicular to this can be canceled by connecting the outputs of the two receivers in parallel or in series. That is, when one of the pressure receiving plates is vibrating as a mass in a direction in which a compressive stress is applied to the piezoelectric vibrator, the other pressure receiving plate acts as a mass for generating a tensile stress, so that the output of the opposite polarity is canceled. However, the vibration generated on the pressure receiving plate by the sound wave does not cancel because the two piezoelectric vibrators generate signals of the same polarity.

[0017]

As described above, an annular piezoelectric vibrator is provided on both sides of a neutral plate, and a wave receiving plate is provided outside the piezoelectric vibrator with respect to the neutral plate. By connecting a cable and installing an electronic circuit on the surface of the neutral plate inside the center of the ring of the ring of the piezoelectric vibrator, it can be used under high water pressure and reduce the receiving sensitivity Therefore, the size and weight of the electronic circuit can be reduced, and no stress is applied to the electronic circuit, so that the reliability is high and the noise output due to the vibration applied to the receiver is reduced.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a receiver according to the present invention, wherein (a) is a perspective view and (b) is a sectional view.

FIG. 2 is an explanatory view of the internal structure of the perspective view shown in FIG. 1;

FIG. 3 is an explanatory diagram of an internal structure of a conventional receiver.

FIG. 4 is a cross-sectional view of the sound receiving unit of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 piezoelectric vibrator 2 pressure receiving plate 3 resin mold 4 piezoelectric vibrator 5 neutral plate 6 electronic circuit 7 cable 8 sound receiving unit 9 substrate 10 metal plate

Claims (1)

(57) [Scope of request for utility model registration] An annular piezoelectric vibrator is provided on both sides of a neutral plate, a pressure receiving plate is provided outside the piezoelectric vibrator with respect to the neutral plate, and a cable is connected to the neutral plate. An electronic circuit provided on a surface of a neutral plate inside the center of the ring of the ring- shaped piezoelectric vibrator.