JPH0429279B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a transducer that transmits and receives multi-frequency ultrasonic signals.

When transmitting and receiving multi-frequency ultrasonic signals, conventionally, a transducer is often provided separately for each frequency.
Therefore, the entire transducer tends to become large.

One purpose of this invention is to simplify the structure of the transducer, thereby reducing the size of the transducer, and transmitting and receiving a single beam width transmission beam with multiple wide beam width transmission beams. An object of the present invention is to provide a multi-frequency ultrasonic transducer formed in the axial direction (same direction) of the transducer.

Another object of the present invention is to form a single transmitting beam and receiving beam with a narrow beam width and a plurality of transmitting beams and receiving beams with wide beam widths in the axial direction (in the same direction) of the transducer. An object of the present invention is to provide a multi-frequency ultrasonic transducer.

These multi-frequency ultrasonic transducers are, for example,
Used in fish finding equipment.

The multi-frequency ultrasonic transducer according to the first invention includes:
A plurality of annular vibrators with different radii are arranged concentrically, and the thickness vibration or height vibration of each of the plurality of annular vibrators is set to be common, and each vibrator is set to have a common frequency. The transducer is excited by a signal, and each vibrator is configured to be excited by a frequency signal of its own radial vibration.

The multi-frequency ultrasonic transducer according to the second invention includes:
A plurality of annular vibrators with different radii are arranged concentrically, and the thickness vibration or height vibration of each of the plurality of annular vibrators is set to be common, and each vibrator is set to have a common frequency. At the same time, each vibrator is excited with a radial vibration unique to each vibrator, and the received signal of this radial vibration is extracted separately. configured.

An embodiment of the present invention will be described below. In FIG. 1, T ₁ , T ₂ , and T ₃ indicate annular vibrators arranged concentrically, and have radii of r ₁ , r ₂ , and r _{3 ,} respectively.

Each annular vibrator T ₁ , T ₂ , T ₃ has a resonant frequency of thickness vibration, height vibration, and radial vibration of the vibrator. The resonant frequencies of each vibrator in the thickness or height direction are set to be the same frequency. Also, the radius of the annular vibrator _T1 is set so that the resonance frequency of its radial vibration is ₂ , and the radius of the annular vibrator _T2 is set so that the resonance frequency of its radial vibration is ₃ . Each radius of T ₃ is set so that the resonance frequency of radial vibration is ₄ . Note that the resonant frequency and radius of the radial vibration of the annular vibrator are respectively set according to the material of the vibrator. For example, when zirconium lead is used as the material of the vibrator, the frequency is 0.98 kHz when the radius is 50 cm.
Therefore, for example, when the radial resonance frequency is set to 6kHz, the radius of the annular vibrator may be set to 50×0.98/6=8.1 (cm).

FIG. 2 shows an example of transmitting and receiving ultrasonic signals using _the transducers T ₁ , T ₂ , and _{T 3 .}
T ₃ is connected to transmitters 4, 5, and
6 and 7, and transmits an ultrasonic signal. The transmitter 4 commonly excites the transducers T ₁ , T ₂ , and T ₃ using a frequency signal ₁ common to the transducers T ₁ , T ₂ , and T ₃ . The reflected waves returning from the detected object are received by the respective transducers T ₁ , T ₂ , and T ₃ , and then sent to the synthesis circuit 8
are guided and phase synthesized. The combined output is then guided to an amplifier 9, amplified, and sent out. or,
The output of the transmitter 5 is guided through the switch 1 to the transducer T ₁ . And the excitation frequency of the transmitter 5 is the oscillator
It is set to a radial resonant frequency of T ₁ . Similarly, the transmitter 6 connects the transducer T ₂ via the switch 2
The transmitter ₇ excites the transducer T ₂ at the radial resonance frequency ₃ of the transducer T ₃ via the switching device ₃ .

After the transducers T ₁ , T ₂ , and T ₃ are excited by their respective radial resonance frequency adapters ₂ , ₃ , and ₄ , their received signals are sent to amplifiers via their respective switchers 1 , 2 , and 3 . Send to 10, 11, and 12.

In FIG. 3, other transducers T ₄ , T ₅ , and T ₆ are arranged concentrically with the transducers T ₁ , T ₂ , and T ₃ in FIG. 1 . The thicknesses or thicknesses of the vibrators T ₄ , T ₅ , and T ₆ are set so that the resonant frequencies in the thickness or height direction are the same. And the transducers T ₄ , T ₅ , and T ₆ are similar to the transducers T ₁ , T ₂ , and T ₃ ,
They are excited by a common transmitter, and their respective received signals are combined in the same manner as in FIG. Therefore,
The received signal after the combination is the received signal in the combined directivity direction of the transducers T ₄ , T ₅ , and T ₆ . In this case, the oscillator
Various directivity characteristics can be obtained by appropriately setting the radii ₄ , ₅ , and ₆ of T ₄ , T ₅ , and T ₆ .

The applicant provided an ultrasonic transducer in Japanese Patent Application Laid-open No. 5570/1983, in which a plurality of groups of annularly arranged transducers are arranged concentrically. This ultrasonic transducer is constructed by appropriately setting the arrangement radius of a plurality of sets of annular transducers arranged concentrically, the transmitting output ratio of each set of annular transducers, or the combining ratio at the time of receiving waves.
This makes it possible to suppress the subpole of the wave transmitting and receiving directivity characteristics as much as possible. Therefore, in FIG. 3 as well, each of the oscillators T ₄ , T ₅ , T ₆
By setting the radius of the wave, the output ratio at the time of wave transmission, and the synthesis ratio at the time of wave reception, it is possible to suppress as much as possible the subpoles of the directivity characteristics at the time of wave transmission and reception. Furthermore, the oscillators T ₁ , T ₂ , T ₃
Similarly to the above, by setting the respective radii, the output ratio at the time of transmitting, and the synthesis ratio at the time of reception, an ultrasonic signal with the same directional characteristic as the composite directional characteristic of transducers T ₄ , T ₅ , and T ₆ is generated. can transmit and receive waves. Therefore, it is suitable for use in underwater detection using dual-frequency ultrasonic signals.

While the composite directional characteristics of the transducers T ₁ to T ₆ are set as described above, various ultrasonic signals can be transmitted and received by utilizing the radial vibration of each transducer.

For example, by appropriately setting the radii of the transducers T ₁ to T ₆ , it is possible to obtain transducers with slightly different resonant frequencies of radial vibration. Therefore, by transmitting and receiving ultrasonic signals using these transducers, it is possible to transmit and receive ultrasonic signals having a broadband frequency characteristic.

Furthermore, by appropriately setting the radius of the annular vibrator, it is possible to transmit and receive waves using different vibrators. For example, set the radius of transducer T ₁ to approximately 3.3 cm.
If zirconium lead is used as the vibrator material as described above, the radial resonance frequency will be 15k.
Hz is obtained. Therefore, the other oscillators T ₂ , T ₃ ,
If the thickness or height of T ₄ , T ₅ , and T ₆ is set so that the resonant frequency in the height direction is 15kHz, ultrasonic waves are transmitted using one of the transducers and the other transducer can be used to receive reflected waves.

According to the first invention, since all the vibrators can be made to have the same height, the structure of the transducer can be simplified, and thereby the size of the transducer can be reduced. Also, by using the thickness vibration or height vibration of multiple annular oscillators, a single narrow beam can be transmitted, and by using the radial vibration of each oscillator, multiple beams can be transmitted with a wide width. It is possible to provide a multi-frequency ultrasonic transducer formed in the axial direction (in the same direction) of a transducer constituted by a plurality of annular vibrators arranged concentrically with the beam.

According to the second invention, the structure of the transducer can be simplified, thereby reducing the size of the transducer. In addition, by using the thickness vibration or height vibration of multiple annular oscillators, we can create a single narrow beam for transmitting and receiving beams, and by using the radial vibration of each oscillator, we can create multiple beams with wide beam widths. It is possible to provide a multi-frequency ultrasonic transducer that forms a transmitting beam and a receiving beam in the axial direction (in the same direction) of a transducer constituted by a plurality of annular vibrators arranged concentrically. .

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention, FIG. 2 is an electrical block diagram thereof, and FIG. 3 shows another embodiment.

Claims (1)

[Claims] 1. A plurality of annular vibrators having different radii are arranged concentrically, and the thickness vibration or height vibration of each of the plurality of annular vibrators is set to be common. A multi-frequency ultrasonic transducer characterized in that a vibrator is excited by the common frequency signal, and each of the vibrators is excited by a unique radial vibration. 2 A plurality of annular vibrators with different radii are arranged concentrically, and the thickness vibration or height vibration of each of the plurality of annular vibrators is set to be common, and each vibrator is set to have the same thickness vibration or height vibration. At the same time, each vibrator is excited with a frequency signal and the received signals of the common frequency are configured to be phase-synthesized, and at the same time, each vibrator is excited with its own radial vibration, and the received signals of the radial vibration are separately generated. A multi-frequency ultrasonic transducer characterized by being configured so that it can be taken out.