JPS625175A - Ultrasonic wave transmitting/receiving element - Google Patents

Abstract

PURPOSE:To enable the receiving of sound waves generated from a transmitting side electrode section with a receiving side electrode, by arranging electrodes on the transmitting and receiving sides on a piezo-electric substrate as bar-like electrode or the like in the combination of electrodes arranged crisscross on the piezo-electric substrate into a desired shape. CONSTITUTION:A circular arc electrode is made up of an right-shaded electrode 15 as square electrode and a circular arc comb-shaped electrode made up of a left-shaded electrode 16 to form a transmitting section. A circular arc electrode opposite in the direction to those on the transmitting side is made up of a right-shaded square electrode 17 formed on the other surface of a piezo-electric substrate as indicated by the doted line and like wise a circular arc comb- shaped electrode is made up of a left-shaded electrode 18 as square electrode opposite in the direction to those on the transmitting side to form a receiving section. With such an arrangement, a sound wave contracted is generated from the piezo-electric substrate at the transmitting side section sequentially operable and fed to a sample, the reflected wave thereof returns to the piezo-electric substrate to be detected with the receiving side electrode as opposed to the transmitting section.

Description

[Detailed Description of the Invention] Production JL4=Example"Dan Year! = The present invention relates to an ultrasonic transmitting/receiving element used in, for example, an ultrasonic microscope or an ultrasonic diagnostic apparatus.

Conventionally, an ultrasonic transducer used in an ultrasonic microscope, etc. has an ultrasonic transmitting/receiving element at one end of an ultrasonic propagation medium with a concave or spherical lens formed at the other end so that ultrasonic waves are focused. has been established.

Here, when the sample to be viewed or the ultrasonic propagation medium is scanned vertically and horizontally, the ultrasonic waves generated from the ultrasonic transmitting/receiving element are surface scanned at the focal position of the concave or spherical lens part of the ultrasonic propagation medium, and the sample of this ultrasonic wave is scanned horizontally and vertically. The acoustic characteristics at each point are detected by receiving reflected waves from the ultrasonic transceiver with an ultrasonic transmitting/receiving element and displayed on a screen such as a CRT.

In addition, ultrasonic transducers used in ultrasound diagnostic equipment are made by cutting long, ultra-thin (several tens of microns) piezoelectric elements into a width of several tens of microns in a direction perpendicular to the length direction, and arranging many elements. By connecting a delay circuit to each electrode and selecting a delay time that connects multiple electrodes, an electrical concave transducer is formed, which focuses the ultrasound beam and transmits and receives it. At this stage of transmission and reception, electrical scanning is performed sequentially in the length direction of the element, thereby displaying an ultrasonic tomographic image on the CRT screen.

However, the ultrasonic transmitting/receiving element of the conventional ultrasonic microscope configured in this way requires a mechanical scanning device to scan the ultrasonic propagation medium or the sample horizontally and vertically.
Further, the ultrasonic transmitting/receiving element of an ultrasonic diagnostic apparatus has the disadvantage that a delay circuit must be connected to the electrode, making the configuration complicated.

■ Trying to do 4 Therefore, in the ultrasound transmitting and receiving elements of conventional ultrasound microscopes,
A mechanical scanning device is required to scan the ultrasonic propagation medium or the specimen horizontally and vertically, and a delay circuit must be connected to the electrode in the ultrasonic transmitter/receiver element of the ultrasonic diagnostic device. The disadvantage was that it was complicated to construct.

In order to solve the above problems, the present invention provides a plurality of square or rectangular electrodes arranged vertically and horizontally on one surface of a piezoelectric substrate, and a plurality of square or rectangular electrodes drawn out from the square or rectangular electrodes. The square or rectangular electrodes are sequentially operated as U-shaped electrodes, comb-shaped electrodes, or arc-shaped electrodes on the transmitting side and receiving side by driving respective predetermined terminals.

The present invention combines terminals pulled out from a plurality of square or rectangular electrodes formed on one or both surfaces of a piezoelectric substrate, thereby forming the square or rectangular electrodes into a predetermined shape and transmitting electrical signals to the transmitting side. gives a compression wave focused at a predetermined angle. When this compression wave is irradiated onto a sample, it is sequentially reflected at a predetermined angle, so by sequentially detecting the reflected signals with a receiving electrode arranged on one side or the other side of the piezoelectric substrate, it is possible to Acoustic characteristics of each part of the sample can be detected without moving the piezoelectric substrate, and without connecting a delay circuit.
By performing electrical scanning sequentially in the length direction of the element, C
Ultrasonic tomographic images can be displayed on the RT screen.

Fig. 1 is a diagram for explaining the present invention in detail, in which rod-shaped electrodes 2a, 2b, 2c, 2d... are arranged in parallel on a piezoelectric substrate 1, and the rod-shaped electrodes 2a, 2b are arranged in parallel on a piezoelectric substrate 1. , 2c, 2d・
The terminals 3a, 3b, 3c, 3d, . . . are connected to the terminals 3a, 3b, 3c, 3d, .

Further, electrodes 4a, 4b, 4c, 4d,... are arranged between the rod-shaped electrodes 2a, 2b, 2c, 2d,...
A common electrode 5 at one end of these electrodes 4a, 4b, 4c, 4d, . . . is connected, and this common electrode 5 is grounded. When an electric signal of a predetermined frequency is supplied from terminals Ta and Tb, which are paired terminals 3a and 3b and 3c and 3d, sound waves are generated from the surface along the boundary between liquid and solid, as shown in Figure 2. . This angle θ is given by θ=5in1Vc/df=sin'λ+/d. However, d is the electrodes 4a, 4b, 4c, 4d, .
..., Vc is the propagation velocity of the sound wave in the liquid, and λ is the wavelength of the sound wave at frequency f.

Therefore, a sound wave generated by a certain combined electrode part on the transmitting side is reflected by the sample, and the reflected wave drives the combined electrode part on the receiving side, which is a predetermined distance away from the combined electrode part on the transmitting side, determined by the angle θ. For example, input terminals Ta and Tb
By simply sequentially inputting electrical signals to ..., signals corresponding to the state of the sample can be sequentially detected from the output terminals.

In addition, in Figure 2, below 100MH, "Lamb wave"
It is effective to use ``Rayleigh waves'' for higher frequencies. In the case of this Lamb wave, as shown in FIG. 3(a), rod-shaped electrodes 2a and 2
This problem occurs due to the configuration in which a comb-shaped electrode consisting of a common electrode connected to electrodes 4a, 4b, . . b, 2c, . I can do it. In the case of Rayleigh waves, as shown in FIG. 3(b), rod-shaped electrodes 2a, 2b, 2 are provided on both sides of the substrate 1.
A comb-shaped electrode consisting of a common electrode connected to electrodes 4a, 4b, 4c, . . . is arranged respectively, and the liquid 6
This can be caused by a structure in which the dielectric protective film 7 is provided on the part that contacts with the glass substrate 8 and the glass substrate 8 is provided on the opposite side.

Note that ZnO2 or a polymer piezoelectric film is used as the substrate.

FIG. 4 shows a perspective view of an ultrasonic transmitting and receiving element according to an embodiment of the present invention, in which a large number of square electrodes 9□0.912.9□1.9 are arranged vertically and horizontally on one surface of a piezoelectric substrate 1. □,...
9□I9□2.923.9□4...,9. □、93□
, 933.934... are provided, and these square electrodes 9□ 9□2.913.914..., 920.9□
2.9□1.924...,93i9,2゜933.9
34... have terminals 10□ and 10□2.10, respectively.
.

1014..., 102□, 10□2, lO□3,10
□. ..., 1O11,103□, 10. ,,103.
... is connected and pulled out. In addition, these square electrodes 91, 912, 911, 91, ..., 9□4
．． 9.2,923.9□,...,910.932.9
13.9□, . . . are formed on one side of the piezoelectric substrate 1 as shown in FIG. 5(a), or on both sides of the piezoelectric substrate 1 as shown in FIG. 5(b). It will be done. Note that a dielectric protective film 11 is provided on these square electrodes, and a glass substrate 12 is provided under the piezoelectric substrate 1 or the square electrodes of the piezoelectric substrate 1.

The ultrasonic transmitting/receiving element of this embodiment configured in this manner has, for example, the square electrode 13 with diagonal lines on the right as a bar-shaped electrode, and the electrode 1 with diagonal lines on the left as shown in FIG. 6(a).
When 4 is sequentially operated as a comb-shaped electrode, the configuration shown in FIG. 1 is obtained. In addition, as shown in FIG. 6(b), the right diagonally lined electrode 13 of the square electrode 13 and the electrode 13' between the rod-like wires
It is also possible to use the 6th electrode as a U-shaped electrode.
As shown in Figure (c), the square electrode 15 with diagonal lines on the right constitutes an arc-shaped electrode, and the electrode 16 with diagonal lines on the left forms an arc-shaped comb-shaped electrode, which serves as the transmitting side. As shown by the dotted line, the square electrode 17 formed on the other side of the piezoelectric substrate 1 with a right diagonal line constitutes an arc-shaped electrode facing opposite to the transmitting side, and similarly the left diagonal line of the positive direction electrode is formed. The applied electrode 18 forms an arcuate comb-shaped electrode facing opposite to the transmitting side, and by using this as the receiving side, a sound wave narrowed from the transmitting side is generated from the piezoelectric substrate 1 at the above-mentioned angle θ.

When this sound wave is sent to the sample, the reflected wave of the sound wave returns to the piezoelectric substrate 1, so that it can be detected by the receiving electrode facing the transmitting electrode.

In the above embodiment, the electrodes formed on the piezoelectric substrate are square, but they may be rectangular.

As is clear from the above description, the present invention combines a large number of square or rectangular electrodes arranged vertically and horizontally on a piezoelectric substrate into a desired shape to form rod-shaped electrodes, U-shaped electrodes, and comb-shaped electrodes. Alternatively, sound waves can be generated with a simple mechanism in which the transmitting side electrode and the receiving side are arranged on a piezoelectric substrate as arcuate electrodes, and the sound waves generated from the transmitting side electrode part can be generated without providing a delay circuit. It has the advantage that the signals can be sequentially received by the receiving electrode.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the present invention in detail, FIG. 2 is an explanatory diagram for generating sound waves using the configuration shown in FIG. 1, FIG. 3 is a block diagram for generating Rayleigh waves, and FIG. 4 is a plan view of the ultrasonic transmitting/receiving element of the first embodiment of the present invention, FIG. 5 is a perspective view of the ultrasonic transmitting/receiving element of FIG. 4 of the present invention, and FIG. 6 is an explanatory diagram of the operation of FIG. 4. be. 1...Piezoelectric substrate, 9□□2.9□1,9□,...
・、9□い9□2.921.924...、931.9
3□, 9, 3.934...square electrode, 102-10
1□, 1013.10, 4..., 1021.10
22.100.102. ..., 10□1.101□,
1013, 1014...terminals. Patent applicant Koji Toda Honda Electronics Co., Ltd. Figure 4 1

Claims (2)

[Claims] (1) Consisting of a plurality of square or rectangular electrodes arranged vertically and horizontally on one surface of a piezoelectric substrate, and terminals drawn out from the square or rectangular electrodes, each predetermined terminal is driven to form the square or rectangular electrode. An ultrasonic transmitting/receiving element characterized in that electrodes are sequentially operated as a U-shaped electrode, a comb-shaped electrode, or an arc-shaped electrode on a transmitting side and a receiving side. (2) The ultrasonic transmitting/receiving element according to claim 1, wherein the rectangular and square electrodes are provided on both surfaces of the piezoelectric substrate.