JPH0441878B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an ultrasonic transducer in which an ultrasonic transducer for transmitting waves and a plurality of ultrasonic transducers for receiving waves are arranged on the same housing. Regarding arrays.

[Conventional technology]

As an ultrasonic transducer array, it was first published in 1983.
There is No. 51477. According to this, it was a structure in which a plurality of array elements having a radius of about 1/10 or less of the wavelength were arranged on the same surface of a buffer made of a material with a value smaller than the specific acoustic impedance of the sound field medium. Therefore, the directivity of the elements exhibits clear unidirectionality without being affected by the mutual radiation acoustic impedance between the elements, and the variation in sensitivity between the elements is small.

[Problem that the invention seeks to solve]

However, according to the above configuration, when the array element is used for wave transmission, the radiation area is small, so there are cases where it is not possible to transmit the acoustic power necessary for the purpose. This is because the maximum acoustic power that can be extracted per unit area is limited by the sound field medium.

For example, to measure the position of an acoustic transponder installed on the ocean floor, an acoustic interrogation signal is transmitted from one transmitter suspended from a ship, and an acoustic response signal from the acoustic transponder that receives the signal is suspended separately. There is an example in which the position of the acoustic transponder is determined by determining the direction of the acoustic transponder from the signal phase difference between the array elements and the distance from the time difference between the transmission and reception.

In such cases, conventionally, a transmitter that outputs the acoustic power necessary for the purpose is provided separately from the receiver array. Since the two transducers had to be suspended in this way, it was necessary to prepare metal fittings to attach the two as one unit, and multiple mechanisms such as two elevating devices were required.

[Means for solving problems]

In order to solve such conventional problems, the present invention provides a buffer with a radius of about 1/10 or less of the wavelength on the same surface of a baffle made of a material whose acoustic impedance is smaller than the specific acoustic impedance of the sound field medium. Multiple receiving ultrasonic transducers are arranged in an L-shape at intervals of 1/4 wavelength or more, and one transmitting ultrasonic transducer with a radius of approximately 1/10 or more of the wavelength and 1/2 or less of the wavelength. The ultrasonic transducer is located at least about one wavelength away from the receiving ultrasonic transducers located at both ends of the L-shape, and further away from other receiving ultrasonic transducers. It is characterized by being arranged as follows.

[Effect]

In the present invention having such a configuration, the ultrasonic transducers for receiving waves having a radius of about 1/10 or less are arranged at intervals of 1/4 wavelength or more, so that the ultrasonic transducers for receiving waves are arranged at intervals of 1/4 wavelength or more. Interference due to the effects of acoustic radiation impedance is prevented, and the distance between the transmitting ultrasonic transducer and the receiving ultrasonic transducer is at least one wavelength apart, so that the acoustic radiation caused by the transmitting ultrasonic transducer is prevented. The influence of radiation impedance on the receiving ultrasonic transducer is also prevented.

Therefore, it is possible to configure an ultrasonic transducer array in which a plurality of receiving ultrasonic transducers and one transmitting ultrasonic transducer are integrated, and the receiving ultrasonic transducer is Because they are arranged in an L-shape, the packaging density is improved, and although the structure has a transmitting ultrasonic transducer with a large radiation surface, the overall structure is a small and high-performance ultrasonic transducer. Arrays become possible.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the arrangement of the elements. In the figure, 1 is a circular baffle, which is made of a material having a value smaller than the specific acoustic impedance of the sound field medium. 2 is an ultrasonic transducer for receiving waves, the radius of its surface is about 1/10 or less of the wavelength, and it is arranged in an L shape on the above-mentioned buffer 1 at 1/4 wavelength intervals or more. be.

Reference numeral 3 denotes a transmitting ultrasonic transducer; this transmitting ultrasonic transducer 3 is separated by at least about one wavelength from the receiving ultrasonic transducers 2 located at both ends of the L-shape; The ultrasonic transducer 3 for transmitting waves is arranged in the above-mentioned buffer 1 so as to be further away from the ultrasonic transducer 2 for receiving waves. It is designed to avoid the effects of radiation.

The position of this ultrasonic transducer 3 for transmitting waves will be explained in more detail.

The effect of mutual radiated acoustic impedance becomes smaller as the distance increases. This is the same distance as the so-called distance at which spatial correlation disappears, and if you are one wavelength away within the same plane, the effect will be only about 10%. The relationship between this spatial correlation coefficient and distance is as shown in FIG.

Therefore, the distance from the periphery of the transmitting ultrasonic transducer 3 to the periphery of the receiving ultrasonic transducer 2 may be approximately one wavelength or more. That is, in FIG. 1, d≧1 wavelength.

By doing this, the transmitting ultrasonic transducer 3 is no longer limited to having a radius of 1/10 wavelength or less, and this allows the transmitting ultrasonic transducer 3 to have the size necessary to transmit the acoustic power required for the purpose. It can be used as an ultrasonic transducer for waves. If unidirectionality is required,
Its radius is allowed to be up to 1/2 wavelength.

FIG. 3 is a longitudinal cross-sectional view of the embodiment, in which ultrasonic transducers 2 for receiving waves having a radius of about 1/10 wavelength or less are arranged on the same surface of a buttful 1 made of Kirk rubber, and ultrasonic vibrations for receiving waves A transmitting ultrasonic transducer 3 with a radius of approximately 1/10 wavelength or more is placed at a position approximately one wavelength or more away from the element 2 on the same surface of the buffer 1, and these are connected to the housing via the buffer 1. It is supported by the bottom plate 4a of No. 4.

These are molded with waterproof rubber 5 and are connected to an electronic circuit 6 inside the housing 4. 7 is a transmission cable.

With the above configuration, even if the receiving ultrasonic transducer 2 and the transmitting ultrasonic transducer 3 are arranged in one housing, there is no spatial correlation between them, and the effects of both ultrasonic transducers are eliminated. This means that you will be able to perform the following tasks.

〔Effect of the invention〕

As explained above, the present invention provides a plurality of wave receiving ultrasonic waves having a radius of about 1/10 or less of the wavelength on the same surface of a buffer made of a material whose acoustic impedance is smaller than the specific acoustic impedance of the sound field medium. Sonic transducers are arranged in an L-shape at intervals of 1/4 wavelength or more, and one ultrasonic transducer for transmitting waves has a radius of about 1/10 or more of the wavelength and 1/2 or less of the wavelength. arranged at least about one wavelength away from the receiving ultrasonic transducers located at both ends of the L-shape, and further away from other receiving ultrasonic transducers, The structure is such that it prevents interference due to the influence of acoustic radiation impedance between the receiving ultrasonic transducers, and also prevents the acoustic radiation impedance of the transmitting ultrasonic transducers from affecting the receiving ultrasonic transducers.

Therefore, it is possible to configure an ultrasonic transducer array in which a plurality of receiving ultrasonic transducers and one transmitting ultrasonic transducer are integrated, and the receiving ultrasonic transducer is Because they are arranged in an L-shape, the packaging density is improved, and although the structure has a transmitting ultrasonic transducer with a large radiation surface, the overall structure is a small and high-performance ultrasonic transducer. The effect is that the array becomes realizable.

In addition, since the transmitting ultrasonic transducer with a large radiation surface and the multiple receiving ultrasonic transducers are integrated as described above, this single ultrasonic transducer array can be used to generate, for example, an acoustic transponder. It can be used for position measurement, etc., and since only one lifting device is required, it also has the effect of improving handling and operability.

[Brief explanation of drawings]

Fig. 1 is an arrangement diagram of elements showing an embodiment of the present invention, Fig. 2 is a graph showing the spatial correlation coefficient, and Fig. 3 is a graph showing the spatial correlation coefficient.
The figure is a longitudinal sectional view of the embodiment. 1... Batsuful, 2... Ultrasonic transducer for receiving waves,
3... Ultrasonic transducer for wave transmission, 4... Housing, 5...
Waterproof rubber, 6...electronic circuit, 7...transmission cable.

Claims (1)

[Scope of Claims] 1. A plurality of receiving ultrasonic vibrations with a radius of about 1/10 or less of the wavelength on the same surface of a buffer made of a material whose acoustic impedance is smaller than the specific acoustic impedance of the sound field medium. The ultrasonic transducers are arranged in an L-shape at intervals of 1/4 wavelength or more, and one transmitting ultrasonic transducer with a radius of about 1/10 or more of the wavelength and 1/2 or less of the wavelength is arranged in the L shape. It is characterized by being arranged at least about one wavelength away from the receiving ultrasonic transducers located at both ends of the letter shape, and further away from other receiving ultrasonic transducers. Ultrasonic transducer array.