JP3171715B2 - Array type ultrasonic probe for high frequency - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array type ultrasonic probe for high frequency (referred to as an array type probe), and more particularly to an array type probe formed by depositing piezoelectric ceramics. .

[0002]

2. Description of the Related Art An array type probe is useful as an ultrasonic wave transmitting / receiving unit in an ultrasonic diagnostic apparatus for medical use or the like, and is electronically driven, for example, a linear or sector. In recent years, there has been a demand for an ultrasonic probe that can be used to increase the frequency of ultrasonic waves, improve the sensitivity by focusing, or be easily manufactured, for example, from the early detection of a small diseased part in the human body (living body).

[0003]

2. Description of the Related Art FIG. 3 is a sectional view for explaining a conventional example of an arrayed probe, in which FIG. 3A is a front sectional view and FIG. 3B is a side view. In the ultrasonic probe, a piezoelectric plate is fixed on a backing material 1 and cut into a plurality of small piezoelectric pieces 2 for division. That is, the micro piezoelectric pieces 1 are arranged in a row in the width w direction. The piezoelectric plate is made of a piezoelectric ceramic such as PZT (lead zirconate titanate) and has electrodes on both main surfaces (not shown). The electrodes are led out for each of the small piezoelectric pieces 2 by a flexible substrate or the like (not shown) when the piezoelectric plate is cut. An acoustic matching layer 3 is formed on the transmitting / receiving surface of each micro piezoelectric piece 1 and an acoustic lens 4 converging in the width direction is provided.

[0004]

However, in the ultrasonic probe having the above structure, the ultrasonic frequency is inversely proportional to the thickness t of the piezoelectric plate. There is a limit due to. For example, if the piezoelectric plate is P
In the case of ZT, practically about 10 MHz (about 0.
It is considered possible to increase the thickness up to 1 mm), and it is difficult to further increase the frequency. Further, in order to maintain good characteristics, the width w of the minute piezoelectric piece is reduced in proportion to the thickness t, and w
The / t ratio must be kept constant. Therefore,
When cutting a piezoelectric plate, it is necessary to cut the piezoelectric plate at a finer pitch and with higher precision as the thickness becomes smaller. The acoustic lens 4 is generally formed of a silicone resin.
The attenuation of the ultrasonic wave is increased, causing a propagation loss. For this reason, for example, it is conceivable to use a piezoelectric plate curved in the width direction, but in this case, there is a problem that it is difficult to manufacture the piezoelectric plate with high accuracy.

[0005]

The present invention relates to PVD (Physical V).
apor Deposition) or CVD (Chemical Vapor Deposition)
Focusing on the point that a piezoelectric thin film can be formed by vapor deposition such as position), firstly, an array-type probe that makes it easy to increase the frequency of ultrasonic waves and does not need to cut the piezoelectric plate, and secondly, on a curved surface It is an object of the present invention to provide an ultrasonic probe in which micro piezoelectric pieces are arranged.

[0006]

According to the present invention, a first columnar electrode is formed on one main surface of a base, and then a piezoelectric ceramic powder is deposited on the columnar electrode to form a columnar deposited piezoelectric plate. A first object of the present invention is to form a second row electrode on the row deposition piezoelectric plate. Further, a second object of the present invention is to form one main surface of the base as a curved surface. Hereinafter, an embodiment of the present invention will be described together with its operation.

[0007]

1 is a schematic view of an ultrasonic probe for explaining an embodiment of the present invention. FIG. 1 (a) is a front sectional view, and FIG. 1 (b) is a side view. The ultrasonic probe includes a base 5, first row electrodes 6, row deposition piezoelectric plates 7, second row electrodes 8, and an acoustic matching layer 9. The base is made of resin or the like, and the width direction of one main surface is a concave surface. The first row-shaped electrodes 6 are composed of a plurality of electrodes which are separated and independent from each other, and are formed so as to be aligned in the longitudinal direction of the base 5. For example, it is formed by vapor deposition while masking an electrode unnecessary portion. The row-shaped deposited piezoelectric plate 7 is P
VD is formed on the first columnar electrode 6. That is, PZT powder is scattered and deposited while only the first columnar electrodes 6 are exposed by the mask. Then, the thickness is controlled by, for example, a monitor device (not shown).
The second columnar electrodes 8 are formed by vapor deposition with the columnar deposited piezoelectric plates 7 exposed by a mask. The acoustic matching layer 9 has a two-layer structure, both of which are arranged in a row and are laminated on the row-stacked piezoelectric plates 7 by PVD or the like. The electrodes on the wave transmitting and receiving surfaces are commonly connected by, for example, lead wires (not shown) or the like, and a filler is buried in each gap such as a row of deposited piezoelectric plates. After the formation of the first and second columnar electrodes 6, 8, a polarization process is performed.

[0008] With such a configuration, PD is obtained by PVD.
The ZT particles are scattered and deposited to form the row-deposited piezoelectric plates 7 which are individually divided. Since the thickness t is controlled by an electronic monitoring device, uniform deposition can be performed in a unit of μm or less. Therefore, the ultrasonic frequency is set to 10 MHz.
The above high frequency can be realized. Further, unlike the conventional example, it is not necessary to cut the piezoelectric plates, and the pitch p between the deposited piezoelectric plates and the width w of the deposited piezoelectric plates are determined by the mask accuracy. Therefore, the workability is improved by eliminating the cutting process,
Moreover, it can be manufactured with high precision. In this embodiment, since one main surface of the base 5 is concave, the ultrasonic waves are converged without using an acoustic lens. Therefore, high sensitivity can be obtained without attenuating the ultrasonic wave, and the number of parts can be reduced.

[0009]

[Other Matters] In the above embodiment, one main surface of the base is concave, but depending on the application, it may be flat or convex, and the shape is limited. Never. Although the acoustic matching layer has two layers, it may or may not have a single layer depending on the application. Further, in the embodiment, a schematic diagram has been described. For example, as shown in FIG. 2, for the electrode lead-out or the like, both sides of the base 5 are protruded to extend the first row-shaped electrodes 6 as shown in FIG. For example, a flexible substrate (not shown) may be connected and led out.
Further, the second row-shaped electrodes 8 on the wave transmitting / receiving surface are commonly connected by a lead wire. However, the second row-shaped electrodes 8 may be integrally connected at the time of vapor deposition, for example, so as not to contact the first row-shaped electrodes. In addition, the row-shaped deposited piezoelectric plates 7 are provided directly on the base 5. However, with the increase in the circumference, the ultrasonic wave has a large amount of attenuation, and the adverse effect due to the reflected wave disappears, so that the backing material becomes unnecessary. Because. Further, the present invention is not limited to PZT, and can be applied to other piezoelectric ceramics such as lead titanate. Also, the ultrasonic frequency can be applied even if it is 10 MHz or less, in short, using a method of forming a piezoelectric thin film by vapor deposition,
An array-type probe having the requirements of claim 1 is included in the technical scope of the present invention.

[0010]

According to the present invention, a first columnar electrode is formed on one main surface of a base, and then a piezoelectric ceramic powder is deposited on the columnar electrode to form a columnar deposited piezoelectric plate. Further, since the second row-shaped electrodes are formed on the row-deposited piezoelectric plates, the frequency of ultrasonic waves can be easily increased, and a high-precision array-type probe can be provided. Further, by forming the base as a curved surface, it is possible to easily provide an arrayed probe having a curved surface.

[Brief description of the drawings]

FIG. 1 is a schematic view of an ultrasonic probe explaining one embodiment of the present invention, wherein FIG. 1 (a) is a front sectional view and FIG. 1 (b) is a side view.

FIG. 2 is a side view of an ultrasonic probe explaining another embodiment of the present invention.

FIG. 3 is a diagram of an ultrasonic probe for explaining a conventional example, wherein FIG. 3 (a) is a front sectional view and FIG. 3 (b) is a side view.

[Explanation of symbols]

5 bases, 6, 8 rows of electrodes, 7 rows of piezoelectric plates, 9
Acoustic matching layer

Claims (1)

(57) [Claims] 1. A base, and a first row of electrodes formed on one main surface of the base and comprising a plurality of individually independent electrodes;
An array type ultrasonic wave for high frequency comprising an arrayed piezoelectric plate formed by depositing piezoelectric ceramics on the arrayed electrodes, and a second arrayed electrode formed on the arrayed piezoelectric plate In the probe , the base is concave and
The first row electrodes are extended from the row deposition piezoelectric plates to extend.
An array type ultrasonic probe characterized by being put out .