JPH06324143A - Ultrasonic wave transducer - Google Patents

Abstract

(57) [Summary] [Objective] The purpose is to improve the directional gain and the injection power of an ultrasonic wave transmitter / receiver used in a dual beam type ultrasonic wave reflection intensity measuring apparatus. [Structure] The elements of the vibrator are arranged concentrically so as to be symmetrical with respect to the center, and the polarities and weights of the electrodes of the element group arranged from the center of the vibrator toward the outer line are changed,
Obtain a wide beam with an ideal directional pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual beam type ultrasonic transducer.

[0002]

2. Description of the Related Art An ultrasonic wave reflection intensity measuring device for measuring the reflection intensity of a single fish by ultrasonic waves and estimating the fish length and the like is well known, but in the so-called single beam system, as shown in FIG. When the fish 13 is located on the main axis Z,
In the case of being located at a position deviated from the directivity main axis Z by an angle θ, there is a difference in the sound pressure level reflected from the fish, and accurate reflection intensity cannot be measured. Therefore, this type of reflection intensity measuring device employs a so-called dual beam system.

FIG. 6 is a diagram for explaining the dual beam system. This system transmits and receives waves at a wide directional angle and
The reflected signal is received even at a narrow directional angle, and the fish 13 has a directional main axis Z.
If it is out of the range, the reflected echo level received at both directional angles has a level difference corresponding to the directional sensitivity difference at a wide directional angle, and the arrival angle θ of the reflected echo is measured from this level difference. Then, the directional sensitivity difference in the transmission / reception with a wide directional angle is corrected.

Conventionally, an ultrasonic wave transmitter / receiver used in such a dual beam system comprises a vibrating element group in which the same vibrating elements are arranged, and transmits / receives a beam having a wide directional angle (hereinafter, abbreviated as a wide beam). When oscillating, only a part of the oscillating element near the center is used, and when receiving a reflected beam with a narrow directional angle (hereinafter abbreviated as a narrow beam), the entire oscillating element group should be received. I have to.

[0005]

As described above, in the conventional dual-beam type ultrasonic transducer of this type, when transmitting and receiving a wide beam, only a part of the vibrating element near the center is used. In addition, since the directivity pattern is uniquely determined by the dimensions of the transducer, there is a problem that a high-performance transducer cannot be obtained. That is, in order to make a high performance device, when transmitting and receiving a wide beam,
Ideally, a wide beam with high intensity and high sensitivity is transmitted and received over a wide range, and it is ideal to have a directional pattern that abruptly attenuates when it exceeds this range. Since the size is determined by the size of the transducer, the current transducer, which has been particularly downsized, cannot obtain sufficient directional gain and injection power.

The present invention has been made to solve the above problems, and an ultrasonic transducer which can transmit and receive a wide beam having a relatively ideal directivity pattern even with a miniaturized transducer is obtained. Is intended.

[0007]

An ultrasonic transducer according to the present invention has a plurality of vibrating elements arranged in series so as to form a plurality of concentric circle rings including the center, and the concentric circles with the center. By changing the electrode polarities and weights of each series of vibrating elements that form a ring, an ultrasonic beam with a wide directional angle is transmitted and received by using all the vibrating elements, and the electrode polarities and weights are changed. Instead, all the vibration elements are used to receive an ultrasonic beam with a narrow directional angle.

[0008]

The ultrasonic wave transmitter / receiver of the present invention changes the applied voltage for polarity and weighting by using, for example, the Bessel function,
By transmitting and receiving an ultrasonic beam with a wide directional angle, it is possible to obtain a beam having a directional ideological pattern having equisensitivity directional characteristics near the center of the main lobe by all the vibrating elements of the vibrator.

[0009]

First, the operating principle of the present invention will be described.
It is a well-known fact that the voltage distribution applied to the ultrasonic transducer at the time of transmission and the directivity pattern of the ultrasonic waves transmitted when this voltage is applied are Fourier transform pairs,
The same applies when receiving. (W. L. Stu
z-man & G.M. A. Ant by Thiele
(See enna Theory and Design). Therefore, in the present invention, the directivity pattern is controlled by the Fourier transform pair by controlling the voltage distribution of the applied voltage.

As described above, in this type of dual-beam type ultrasonic wave transmitter / receiver, an ideal wide beam directivity pattern transmits / receives a high-intensity, high-sensitivity beam in a wide range, and An ideal pattern is a pattern that abruptly attenuates when it exceeds this range. Therefore, in the present invention, as shown in FIG. 1, for example, a Bessel function (Besselselfun) is used.
action: cylindrical function). That is, FIG.
As shown in (A), when the polarity and level of the voltage applied to each vibrating element group are made to correspond to 2J _I (γ) / γ, (J _I
() Is a Bessel function), as shown in FIG. 1 (B), it has isosensitivity characteristics near the center of its main lobe, and beyond that range, a relatively ideal directional pattern close to zero is obtained. To be

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing an arrangement example of the vibration elements in the vibrator of the present invention, and reference numerals 1, 2, 3, 4, 5, and 6 represent series of vibration element groups having different wiring connection series. That is, all the dice-shaped vibrating elements have the same polarity and weight, but the wiring connection sequence is such that wiring is formed so as to form a plurality of concentric ring rings (reference numerals 2 to 6) including the vibrating element group 1 at the center. The connections are made in series, that is, the same reference numerals 1 to 6 mean that the transducer elements are in the same series.

FIG. 3 shows an embodiment of a circuit configuration for applying a voltage to the array of vibrators shown in FIG. 2. Reference numerals 1 to 6 mean the vibration element series shown in FIG. 1, and 7 denotes a wide beam. Transformer 8 is a narrow beam transformer.

Next, the operation of the embodiment will be described. Figure 2
The transducer groups having the same reference numeral are connected to each other in the same manner, and as shown in FIG.
The polarity is opposite to that of the element group of No. 6. Also, FIG.
In the wide beam transformer 7, the secondary side winding ratio is set so that the output voltage of each tap is different (V1 to V6), as shown in FIG.
By matching with the applied voltage of, the directivity pattern of the wide beam transmitted / received can be a relatively ideal directivity pattern shown in FIG. 1 (B).

On the other hand, the received narrow beam is output from the narrow beam transformer 8. Here, the element groups 1 to 6 have the same winding ratio and are connected with the same polarity. Since the polarities of the signals between them are in phase and there is no weighting between the respective element groups, it is possible to obtain a reception signal having a directional characteristic determined by the dimensions of the transducer. This state is shown in FIG.

[0015]

As described above, since the ultrasonic wave transmitter / receiver of the present invention can transmit / receive a wide beam with a relatively ideal directivity pattern and can receive a narrow beam by using all transducers,
The directivity gain and the injection power can be greatly improved even with a small device, and the high-performance device can be obtained such that the reflection intensity of a single fish can be accurately measured at a deep depth.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the operation principle of the present invention.

FIG. 2 is a diagram showing an example of arrangement of vibrating elements in an example of the present invention.

FIG. 3 is a block diagram showing an embodiment of a circuit configuration of the present invention.

FIG. 4 is a diagram showing a directivity pattern of the transceiver according to the present invention.

FIG. 5 is a diagram for explaining a single-beam type transceiver.

FIG. 6 is a diagram for explaining a defect of a conventional device.

[Explanation of symbols]

 1-6 Vibration element groups of the same series 7 Wide beam transformer 8 Narrow beam transformer 11 Transducer 13 Fish

Claims (2)

[Claims] 1. An ultrasonic wave transmitter / receiver which transmits and receives an ultrasonic beam at a wide directional angle and receives a reflected signal at a narrow directional angle in order to perform level correction according to the arrival angle of the reflected signal. Means for arranging in series so as to form a plurality of concentric circle rings including the center, and changing the polarity and weighting of each of the series of vibrating elements forming the center and each concentric circle ring, to obtain a wide directional angle. A means for transmitting and receiving an ultrasonic beam, a means for receiving and transmitting an ultrasonic beam at a narrow directional angle without changing the polarity and weighting of each series of vibrating elements forming the center and each concentric ring are provided. Characteristic ultrasonic transducer. 2. The polarities and weighting changes when transmitting and receiving an ultrasonic beam with a wide directional angle are determined by arranging voltages of a voltage distribution using a Bessel function (column function) in series. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer is partially applied to the vibration element.