JP2936007B2 - Ultrasonic probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ultrasonic probe in the application field, and particularly relates to an ultrasonic probe formed by combining a piezoelectric plate.

(Background of the Invention) An ultrasonic probe is used, for example, as a transmitting / receiving part of an ultrasonic wave in a medical ultrasonic diagnostic apparatus. In recent years, there has been an annular type in which a piezoelectric plate is combined and, for example, concentric electrodes are formed.

(Prior Art) FIGS. 5 and 6 are views of an ultrasonic probe for explaining such a conventional example.

In the ultrasonic probe, for example, a piezoelectric plate such as PZT is fixed on the work plate 1, and cut into two-dimensional x and y directions to be divided into a plurality of piezoelectric pieces 2. After the filling material 3 is buried between the grooves and integrated (composite) (FIG. 5), it is removed from the working plate 1. Next, a concentric electrode 4 having a circular center and an outer ring is provided on one main surface of the composite piezoelectric piece 2.
(Ab) is formed by forming the common electrode 5 on the other main surface as shown in FIG.
b). Then, for example, a delay signal is applied to, for example, the concentric electrode 4 to mechanically drive the sector. In such a device, the acoustic impedance is reduced and the transmission / reception efficiency is improved by the combination.

(Problems of the prior art) However, in the ultrasonic probe having the above-described configuration, the acoustic impedance of the vibrating portion formed with the concentric electrodes 4 (ab) and the non-vibrating portion therebetween are substantially equal. Therefore, there is a problem that the acoustic coupling between the vibrating parts is made dense to cause signal leakage (crosstalk), thereby deteriorating acoustic characteristics.

(Object of the Invention) It is an object of the present invention to provide an ultrasonic probe having reduced acoustic noise and improved acoustic characteristics.

(Solution) According to the present invention, a unitary piezoelectric plate is arranged with a gap, and a filler is provided in the gap to electrically and acoustically insulate the unitary piezoelectric plate to form an integrated piezoelectric plate. The unit piezoelectric plate is divided into a number of piezoelectric small pieces, a filler is provided in the cut groove, the integrated piezoelectric plate is integrated again, and the integrated piezoelectric plate corresponding to the unit piezoelectric plate is integrated. Basically, a small piece is used as an integral unit piezoelectric plate, input / output electrodes are formed on one main surface of the integral unit piezoelectric plate, and a common electrode is formed on the entire other main surface of the integral unit piezoelectric plate. Solution. Hereinafter, an embodiment of the present invention will be described with reference to a manufacturing process.

(Embodiment) FIGS. 1 to 3 are views of an ultrasonic probe during a manufacturing process for explaining an embodiment of the present invention. In each of the figures, (a) is a plan view, and (b) is a cross-sectional view of the central portion of (a).

The piezoelectric plate is made of PZT as described above, and is polarized by forming electrodes 6 on both main surfaces. In this embodiment, first, unit piezoelectric plates 7 (ab) having a circular center and an outer ring are arranged concentrically with an interval G therebetween. Then, a filler 8 such as an organic material that is electrically and mechanically insulated is provided in the gap between the unit piezoelectric plates 76 (ab) and integrated. The integrated unit piezoelectric plate is referred to as an integrated piezoelectric plate. Next, the integrated piezoelectric plate is cut in a two-dimensional direction with a groove width g, and a large number of piezoelectric small pieces 9 are cut.
To form At this time, the ratio w / t of the thickness t and the width w of the piezoelectric small piece 9 is set to be 0.4 to 0.6 or less. Then, the same filler material 8 as described above is embedded in each of the cut grooves 10 and integrated again to form a composite. The integrated piezoelectric small piece 9 is referred to as an integrated unit piezoelectric plate 11 (ab). Then, the integrated unit piezoelectric plate 11
(Ab) A common electrode 12 is formed on the other main surface, and a concentric electrode 13 (ab) for input and output is formed on one main surface. Make up the child.

In such a device, the integrated unit piezoelectric plate 11 (ab) as a vibrating portion formed with the concentric electrodes 13 (ab) is compounded, and the non-vibrating portion between the concentric electrodes is made of only an organic filler. Become. Therefore, since the acoustic impedance of the vibrating part and the non-vibrating part are greatly different, the acoustic coupling between the two can be weakened to reduce crosstalk and improve the acoustic characteristics.

(Other Matters) In the above embodiment, the unit piezoelectric plates are made concentric (annular), and the unit piezoelectric plates are integrated beforehand. After that, the filler may be embedded in the gap and the cutting groove. In this way, the workability of the filling material can be improved only once. Further, the unit piezoelectric plate can be applied even if it has a matrix shape as shown in FIG. 4, for example. In this case, it is only necessary to cut one piezoelectric plate while changing the interval G and the groove width g, so that it is not necessary to perform positioning as a unit piezoelectric plate in advance. Further, even if it is an annular type, it can be formed of one piezoelectric plate as long as it can be divided concentrically with high accuracy. Also,
Although it is assumed that the piezoelectric plate has the electrode 6 formed in advance and is polarized, as is clear from the above description, the concentric electrode 13 is again formed.
Since (ab) and the like are formed, the electrodes need only be polarized even if the electrode 6 is not provided in advance. Polarization may be performed after the formation of the concentric electrodes 13 (ab) and the like, and these can be freely changed.

(Effect of the Invention) According to the present invention, an integrated piezoelectric plate is formed by disposing a unitary piezoelectric plate with a gap, providing a filler that electrically and acoustically insulates the gap, and cutting the integrated piezoelectric plate. A groove is provided to divide the unit piezoelectric plate into a number of piezoelectric pieces, and a filler is provided in the cut groove to integrate the integrated piezoelectric plate again, and a portion corresponding to the unit piezoelectric plate is integrated. The piezoelectric piece is an integrated unit piezoelectric plate, input / output electrodes are formed on one main surface of the integrated unit piezoelectric plate, and a common electrode is formed on the entire other main surface of the integrated electric plate. Since this is a basic solution, it is possible to provide an ultrasonic probe having reduced acoustic noise and improved acoustic characteristics.

[Brief description of the drawings]

1 to 3 are views for explaining an embodiment of the present invention with manufacturing steps, FIG. 1 is a view of an integrated piezoelectric plate, FIG. 2 is a view of an integrated unit piezoelectric plate as an annular type, FIG. 3 is a diagram in which concentric electrodes and a common electrode are formed on an integrated unit piezoelectric plate, in which (a) is a plan view and (b) is a cross-sectional view. FIG. 4 is a view for explaining another embodiment of the present invention, and is a matrix type plan view. FIG. 5 is a view for explaining a conventional composite piezoelectric plate, FIG. 6 (a) is a top view of the composite piezoelectric plate on which the annular electrode is formed, and FIG. 6 (b) is a bottom view.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H04R 17/00 330 A61B 8/00 H04R 17/00 332 G01N 29/24

Claims (2)

(57) [Claims] A unit piezoelectric plate is disposed with a gap therebetween, and an electrically and acoustically insulating filler is provided in the gap to form an integrated piezoelectric plate. Further, a cut groove is provided in the integrated piezoelectric plate. The unit piezoelectric plate is divided into a large number of piezoelectric pieces, a filler is provided in the cut grooves to integrate the integrated piezoelectric plate again, and the integrated piezoelectric pieces corresponding to the unit piezoelectric plate are integrated. The integrated unit piezoelectric plate is formed by forming input / output electrodes on one main surface of the integrated unit piezoelectric plate and forming a common electrode on the entire other main surface of the integrated piezoelectric plate. Ultrasonic probe. 2. An integrated piezoelectric plate having a unit piezoelectric plate disposed with a gap and a cutting groove provided to divide the unit piezoelectric plate into a number of piezoelectric pieces, and a filler provided in the gap and the cutting groove. An integrated input / output electrode is formed on one main surface of the integrated unit piezoelectric plate, using an integrated piezoelectric piece corresponding to the unit piezoelectric plate as an integrated unit piezoelectric plate. An ultrasonic probe comprising a common electrode formed on the entire main surface.