JPH0548040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an ultrasonic transducer in which directional characteristics are improved by arranging bent transducers in a plane such that they are located at each vertex of a triangle.

(Prior Art and its Problems) Conventionally, an ultrasonic transducer using a small bending type vibrator has a structure shown in FIG. 1. In this figure, a support ring 2 is formed on a substrate 1, a bending type vibrator 3 having a bimorph structure in which two piezoelectric elements are bonded together is supported by the support ring 2, and the ultrasonic wave of the bending type vibrator 3 is A matching box 4 is attached to the transmitting/receiving wave surface. The electrodes on the upper and lower surfaces of the bending type vibrator 3 are connected to terminal pins 5A, 5.
B, respectively.

However, in a planar structure using a small bending type vibrator as shown in FIG. 1, the directivity characteristics are broad, and it is difficult to reduce side lobes. For this reason, in order to improve the directivity characteristics, a large transducer was used, or a horn was used to narrow down the ultrasonic beam. However, when a large-sized vibrator is used or a combination structure of a small-sized vibrator and a horn is adopted, the overall shape inevitably becomes large.

(Purpose of the Invention) As a result of various experiments, the inventor of the present invention found that by arranging bent vibrators in a plane so that they are located at each vertex of a triangle and electrically connecting them in parallel to transmit and receive waves, the directivity characteristics can be significantly improved. The object of the present invention is to improve the directional characteristics by arranging the bending type vibrators at each vertex of a triangle, thereby making the shape smaller and lighter. An object of the present invention is to provide an ultrasonic transducer that is capable of achieving high performance.

(Embodiments of the Invention) Hereinafter, embodiments of the ultrasonic transducer according to the present invention will be described with reference to the drawings while comparing them with a comparative example.

Comparative Example 1 As shown in FIG. 2, the ultrasonic wave transmitting/receiving elements 10 having the structure shown in FIG. 1 were arranged in a straight line, and the directional characteristics were measured by electrically connecting them in parallel. The measurement results were as shown in FIGS. 3 to 6. Here, FIG. 3 shows a case where there are two elements 10, FIG. 4 shows a case where there are three elements, FIG. 5 shows a case where there are four elements, and FIG. 6 shows a case where there are five elements. As can be seen from FIGS. 3 to 6, side lobes appear near the directivity direction (0°) and the directivity characteristics are not improved much.

Comparative Example 2 As shown in FIG. 7, four ultrasonic transceiver elements 10 having the structure shown in FIG. 1 were arranged in a square array, connected in parallel, and their directivity characteristics were measured. The measurement results are shown in FIG. 8, where side lobes appear on both sides of the directional direction (0°), and the directional characteristics have not been improved.

Example As shown in FIG. 9, three ultrasonic transceiver elements 10 shown in FIG. 1 were arranged in a triangular shape on the same substrate 1A. As shown in FIG. 10, the elements 10 are arranged such that the center of each element is located at the vertex of an equilateral triangle, and the vibration surfaces of each bending type vibrator are on the same plane. are connected in parallel and excited with the same phase. In this case, the directivity characteristics are as shown in Figure 11, and the side lobes on both sides of the directivity direction (0°) are significantly suppressed, and the directivity characteristics are significantly improved. (Effects of the Example) It is clear from the above explanation. As shown in the example, only when the ultrasonic transmitting/receiving elements are arranged in a plane so as to be located at each vertex of a triangle, a remarkable effect of improving the directional characteristics can be obtained. An ultrasonic transducer can be realized. It has also become easier to produce a device with performance equivalent to or better than that using a large vibrator or horn. As a result, it can be fully used in distance meters, object detection devices, remote control devices, etc. used in continuous autofocus of VTRs and the like.

(Supplementary explanation of the embodiment) In Fig. 9, the bending type vibrator 3 is placed on the same substrate.
Although three ultrasonic wave transmitting/receiving elements 10 are arranged in this embodiment, each element may be individually provided in a case and they may be arranged in a triangular arrangement. Further, the structure of each ultrasonic wave transmitting/receiving element does not necessarily have to be the same as that in FIG. 1, and can be changed as appropriate.
For example, a unimorph structure in which a piezoelectric element and a metal plate are bonded together can be used as a bending type vibrator.

(Effects of the Invention) As explained above, according to the ultrasonic transducer of the present invention, three bending type vibrators each made of a piezoelectric element or a piezoelectric element and a metal plate are used, and the transducer is positioned at each vertex of a triangle. Since the structure is arranged in a plane, it is possible to reduce the size and weight, and also to significantly improve the directivity characteristics.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a conventional ultrasonic transducer, Fig. 2 is an explanatory diagram showing a linear arrangement configuration in Comparative Example 1, and Figs. 3 to 6 are illustrations of a linear arrangement configuration. Graph showing the directional characteristics, FIG. 7 is an explanatory diagram showing the square arrangement in Comparative Example 2, FIG. 8 is a graph showing the directional characteristics in the case of the square arrangement, and FIG. 9 is the ultrasonic wave transmission and reception according to the present invention. A perspective view showing an embodiment of the device, 1st
Figure 0 is an explanatory diagram showing the triangular arrangement of the embodiment.
FIG. 1 is a graph showing the directional characteristics in the case of the example. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Support ring, 3... Flexible vibrator, 4... Matching device, 10... Ultrasonic wave transmitting/receiving element.

Claims (1)

[Scope of Claims] 1. An ultrasonic transducer characterized in that bending type vibrators made of piezoelectric elements or piezoelectric elements and metal plates are arranged in a plane so as to be located at each vertex of a triangle. 2. The ultrasonic transducer according to claim 1, wherein each of the bending type transducers is electrically connected in parallel and driven by the same excitation source.