JPH0453585Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an ultrasonic omnidirectional transducer used in transponders, fish finders, and the like.

<Prior art> Conventionally, the omnidirectional transducer 3 for transmitting and receiving used in this type of transponder, fish finder, etc.
A ceramic piezoelectric element material is molded into a shape 4 like a spherical shell with a part cut out or a cylindrical shape as shown in FIG.

<Problems to be solved by the invention> Therefore, among the conventional oscillators of this type mentioned above,
The former has good directional characteristics, but has the disadvantage of being expensive due to manufacturing difficulties, and the latter has a problem with directional characteristics, such as low sensitivity in the cut direction of the outer edge of the cylinder.

In a transponder, a handset receives ultrasonic waves transmitted from a master station from any direction, and must immediately respond and transmit a reply wave toward the master station. In addition, in fishing, the most important information is first to detect schools of fish to be caught in all directions. Therefore, it is believed that the excellent omnidirectional performance of the transducer of the ultrasonic transmitter/receiver of the fish finder installed on a fishing boat is an essential factor that determines the catch of that fishing boat. This is no exaggeration (see Figure 4).

In either case, the performance and characteristics of the vibrator will influence the performance of the entire device.

However, as mentioned above, a vibrator with excellent omnidirectional characteristics is expensive, so there is a problem in that not every device can be equipped with an expensive omnidirectional vibrator.

Therefore, the present invention solves these conventional problems and satisfies the current requirements for resonators, and is a resonator that has excellent omnidirectional characteristics, and is far more expensive than conventional products. The purpose is to provide a vibrator with a structure that can be manufactured at low cost.

<Means for Solving the Problems> The structure of the present invention for achieving the object will be explained using FIGS. 1 and 2 corresponding to the embodiments. Two solids with approximately the same radius on both sides of the vibrating surface of
It has a structure in which couplers 2, 2 each having a hemispherical metal body are joined at their respective surfaces.

<Function> Since the present invention has such a structure, the ultrasonic vibrations generated by the expansion and contraction of the disk-shaped diaphragm 1 in the thickness direction are transmitted to the couplers 2 through the joint surfaces. , propagates through couplers 2 and 2,
radiated into the medium from the outer surface.

<Examples> Examples of the present invention will be described below based on the drawings.

1 and 2 show an embodiment of the present invention. In this embodiment, two solid couplers 2, 2 made of metal such as brass and semi-spherical with a radius approximately equal to that of the diaphragm 1 are attached to both the front and back of the vibration surface of the ceramic disc-shaped Langevin type diaphragm 1.
The flat surfaces of the pieces are bonded together with an adhesive.
It is pasted together to form a sphere.

When using the thickness vibration of a piezoelectric vibrator, the phase of vibration of the vibrating surface is such that both the front and back sides vibrate in the same phase.
In the case of transmission, ultrasonic vibrations of several tens of kilohertz are input from the joint surface of the hemispherical coupler where the output of the transmitter is closely bonded to the vibration surface of the diaphragm, and propagate through the coupler with little loss. It is radiated radially from the surface of the coupler into a medium such as seawater.
In the case of reception, vibration is input from the medium through the coupler surface in the opposite direction to the above, propagated through the metal body of the coupler, transmitted to the vibration surface of the diaphragm through the joint surface, and generates reception input. This is the electrical input for the receiver.

In other words, in the case of a fully spherical vibrator in which two of the above-mentioned solid metal couplers are attached to both sides of the vibrating surface of a piezoelectric diaphragm, and the couplers are bonded at their surfaces, the couplers are sandwiched between them in a sandwich-like manner. Apart from the resonance mode of the piezoelectric diaphragm, it has a mechanical resonance mode as a whole sphere. In other words, it is possible to radiate ultrasonic waves in all directions by using the respiratory vibration effect of the outer periphery as the basis of the sphere's vibration.

Furthermore, since the coupler is made of metal, there is no need to separately provide an electrode, and the lead wire can be conveniently drawn out from anywhere on the coupler surface.

The material of the diaphragm 1 in the above embodiment may be a piezoelectric polymer material such as PVDF other than ceramic, and the material of the coupler may be aluminum or the like other than brass. Furthermore, in the above embodiment, a structure in which two couplers 2, 2 are bonded and fixed to both the front and back surfaces of the vibrating surface was explained, but in the case of a hemispherical vibrator bonded to either the front or back surface, the directivity characteristics will be different. This can be said to be an embodiment of the present invention.

Although the embodiments considered to be representative of the present invention have been described above, the present invention is not necessarily limited to the structure of these embodiments, and the present invention is not necessarily limited to the structure of these embodiments. It can be implemented with appropriate modification within the scope of achieving the following effects.

<Effects of the invention> As is already clear from the above explanation, the invention has the following effects:
To obtain an inexpensive and excellent omnidirectional oscillator with a simple structure in which a common metal hemispherical coupler is bonded to the vibration surface of an easily available disc-shaped ceramic diaphragm. It has come to be possible to expect significant practical effects.

[Brief explanation of the drawing]

FIG. 1 is an external view showing the outline of an embodiment of the present invention;
FIG. 2 is an explanatory diagram showing the operation of an embodiment of the present invention, FIG. 3 is an external view of a conventional example, and FIG. 4 is an explanatory diagram showing an example used in a fish finder. In the figure, 1 indicates a diaphragm, and 2 indicates a coupler.

Claims (1)

[Scope of utility model registration request] A Languevain type ultrasonic waveless device is constructed by joining two hemispherical solid metal couplers 2, 2 having approximately the same radius on both sides of the vibration surface of a disc-shaped diaphragm 1 at their plane parts. Directional oscillator.