JP3302124B2 - Ultrasonic probe and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe used in an ultrasonic endoscope or the like used in the medical field and a method of manufacturing the same, and more particularly, to an ultrasonic probe having an improved electrode structure of a piezoelectric element. And a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, ultrasonic probes have been rapidly growing in demand as medical ultrasonic diagnostic devices in addition to nondestructive inspection devices. Probes such as ultrasonic endoscopes emit high-frequency acoustic vibrations from the ultrasonic transducer into the living body,
The reflected ultrasonic waves are received by an ultrasonic transducer, and different information is processed according to slight differences in interface characteristics, thereby obtaining a cross-sectional image of the inside of a living body.

[0003] A transducer of an ultrasonic transducer is generally composed of a piezoelectric element, an acoustic matching layer, and a back load material. This ultrasonic transducer applies a high-frequency voltage pulse to the piezoelectric element using the electrode formed on the surface of the piezoelectric element, causes the piezoelectric element to resonate, rapidly deforms, and generates an ultrasonic pulse. is there. However, in the case of high frequency and miniaturization, such as an ultrasonic probe for blood vessels, the shape of the piezoelectric element becomes small and the thickness becomes very thin. Has become very difficult. In addition, although the electrode material has a high adhesion strength to a resin or a piezoelectric ceramic, a perfect electrode material has not yet been found, such as not being able to sufficiently bring out the piezoelectric characteristics. In general, a silver-baked electrode is used as an electrode, but when higher frequency and higher precision are required, the electrode is formed by vapor deposition or sputtering of a metal or alloy such as gold, silver, and nickel. There are many things.

[0004] As a conventional example, Japanese Patent Application Laid-Open No. Hei 5 (1993) shown in FIG.
As in the ultrasonic probe described in JP-A-13542, a first ultrasonic probe formed on the back load member 7 provided on the base 25 from the main plane to the side surface of the piezoelectric element 3 of the ultrasonic probe. There is a configuration having an electrode 5a and a second electrode 5b formed at a position facing the first electrode 5a while ensuring insulation with the first electrode 5a. 22 is a flexible substrate. For connection to the piezoelectric element 3, a method is adopted in which conduction is established by the solder 18 through the side surface of the piezoelectric element 3 or a folded electrode. Then, in order to prevent the corner electrodes 5a, 5b from being torn or peeled off at the time of cutting, each of the electrodes 5a, 5b is cut.
The peripheral portion of the side electrode 5b is reinforced by the reinforcing electrode 24.

[0005]

However, in a conventional ultrasonic probe having a structure as disclosed in Japanese Patent Application Laid-Open No. Hei 5-13542, the electrodes 5a and 5b are formed to extend to the side surface of the piezoelectric element 3. ing. Therefore, there are several problems described below. In other words, because of the configuration in which the electrodes 5a and 5b are provided on the side surfaces, the direction of the polarization axis approaches the horizontal direction (radial direction) inverted by 90 degrees in the peripheral portion of the side surface electrodes, and the amplitude of an unnecessary mode is likely to occur. . Then, due to insulation measures at the time of polarization, the ratio of the portion where the positive and negative electrodes 5a and 5b are located at opposing positions where ultrasonic waves are actually transmitted and received decreases. In a blood vessel probe or the like in which the volume itself of the piezoelectric element 3 is regulated, the reduction in the part to be actually driven greatly affects the sensitivity and leads to deterioration in image accuracy. Further, as the frequency is increased, the thickness of the piezoelectric element 3 is reduced, and it is very difficult to form the electrodes 5a and 5b on the side surfaces.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an ultrasonic probe using a piezoelectric element which can be easily miniaturized and easily connected, and a method of manufacturing the same. And

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises at least one or more acoustic matching layers or acoustic lenses, a piezoelectric element having electrodes on the front and back surfaces, and a back load. In the ultrasonic probe made of a material, at one end of the piezoelectric element, a surface non-electrode portion provided on the front surface, and at the other end of the piezoelectric element, a back non-electrode provided on the back surface Portion, the other end of the piezoelectric element, provided at a position facing the back non-electrode portion, a surface electrode thick portion exposed from the side surface of the other end of the piezoelectric element, A back electrode thick portion provided at a position facing the front non-electrode portion at the one end, and exposed from a side surface of the one end of the piezoelectric element;
It is characterized by having.

According to a second aspect of the present invention, there is provided an ultrasonic probe according to the first aspect, comprising at least one or more acoustic matching layers or acoustic lenses, a piezoelectric element having electrodes on front and back surfaces, and a back load material. In manufacturing the stylus, at least one or more acoustic matching layer or acoustic lens, and after laminating and joining the back load material, cut and expose the surface electrode thick part and the back electrode thick part, and expose In addition, there is provided a method of manufacturing an ultrasonic probe, wherein the connection is made at the thick portion of the front electrode and the thick portion of the back electrode.

[0009]

According to the present invention, a thick portion of the front electrode exposed from the side surface of the other end of the piezoelectric element and a thick portion of the back electrode exposed from the side surface of the one end of the piezoelectric element are provided. Since an ultrasonic probe is formed by connecting wires at a thick portion of an electrode, an ultrasonic probe using a piezoelectric element having an electrode that can be easily connected without providing a side electrode, and a method of manufacturing the same are disclosed. Can be provided.

[0010]

Embodiment 1 (Configuration) This embodiment will be described with reference to FIGS. FIG. 1 is a perspective view of a piezoelectric element, FIG.
4 and 5 are perspective views showing a method of manufacturing the transducer portion of the ultrasonic probe, and FIG. 6 is a sectional view of the manufactured ultrasonic probe.

First, a rectangular piezoelectric ceramic thin plate 1
Then, the electrode thick portions 2a and 2b are formed on the front and back of the main plane as shown in FIG. Next, as shown in FIG. 2, the electrode material 4a is not applied to a portion where conduction with the one electrode thick portion 2a is obtained and where the electrode thick portion 2b is provided on the opposed flat surface (opposite surface). Thus, a flat electrode 5a is formed. Similarly, the opposing electrode 5b is formed, and the piezoelectric element 3 used for the ultrasonic probe of this embodiment is manufactured.

More specifically, a lead ceramic titanate (PT) -based thin plate 1 having a thickness of 0.11 mm and a resonance frequency of 20 MHz (the temperature at which spontaneous polarization disappears is 320 ° C.) is prepared by lapping, and a silver paste is prepared. Is thickly applied by screen printing, dried and baked to form electrodes 2a and 2b having a thickness of about 35 μm. Next, a surface treatment such as ion bombardment is performed, and a planar electrode 5 is formed on the main plane portion as shown in FIG. 2 by vapor deposition, and a polarization operation is performed to produce the piezoelectric element 3. As shown in FIG. 4, an acoustic matching layer 6 made of an epoxy resin is formed on this piezoelectric element 3, and a back load material 7 made of an epoxy resin containing a tungsten filler is formed, thereby producing a laminate. Next, the solid line 19 in FIG. 4 is cut by a precision cutting machine to produce a structure in which the electrode thick portion is exposed on the side as shown in FIG. Further, a portion 26 indicated by a solid line in FIG. 5 is cut by a precision cutting machine to produce one small vibrator portion.

Then, as shown in FIG. 6, this transducer is mounted on a housing 12 formed by processing a metal pipe.
The insulating plate 10 is fixed with an adhesive and then fixed, and the electrode thick portion exposed on the side surface of the transducer is connected via the conductive resin 9. At this time, the GND electrode 5a on the acoustic emission surface side is once connected to the housing 12 with the conductive resin 9, and is connected by soldering to a coaxial cable passing through the inside of the flexible shaft at a housing pipe (not shown). On the other hand, the connection of the plus side electrode 5b is
2 to ensure insulation from
On the reference numeral 0, the conductive resin 9 is connected to the coaxial cable signal line 11. The ultrasonic probe 17 was manufactured with the above configuration. 9 parts of the conductive resin is molded and protected by the epoxy resin 8. Also, housing 1
2 and the flexible shaft 13 are brazed by silver brazing 14, and the housing 12 is made of corrosion-resistant stainless steel plated with electroless nickel so that soldering is possible.

(Operation) By the above-mentioned method, conduction from the thick electrode portion exposed on the side surface to the conductive resin 9 can be ensured. Since the positive and negative electrodes 5a and 5b on the opposing planes that actually function as transducers are thin, no mechanical loss occurs. Further, when the acoustic matching layer and the back load material are formed by the casting method or laminated by bonding, even if the resin or the adhesive runs out, the problem is eliminated by cutting after lamination.
Further, even if the accuracy at the time of laminating the acoustic matching layer and the back load material is rough, there is no problem because the cutting is performed, and the ultrasonic probe can be easily manufactured. In this embodiment,
The thick electrode portion was provided by a baked silver electrode, and then the silver electrode was formed on the main plane by vapor deposition, but the order of application may be any, and the electrode material may be any material as long as the electrode thick portion has a thickness. The same operation and effect can be obtained with a conductive resin, and the same operation and effect can be obtained as long as the material of the electrode applied to the main plane portion is a metal such as gold, silver, copper or the like and a conductive material mainly containing a metal. can get.

(Effect) By manufacturing by the above-described method, connection can be easily performed without using a side electrode or a folded electrode having a problem in reliability, and reliability is improved. In addition, since the lamination accuracy of the acoustic matching layer and the back load material is not required, and it is not necessary to consider the adhesion of the resin to the electrodes 5a and 5b, the ultrasonic probe can be easily manufactured. Since the ratio of the positive and negative electrodes 5a and 5b at the positions facing each other is higher than that with the side electrodes, the actual drive unit may be large and small to obtain the same level of sensitivity. 12 is shortened, and the commercial value is improved. Although the band-shaped electrode thick portions 2a and 2b are formed on the piezoelectric ceramic thin plate 1 in FIG. 1, similar effects can be obtained in the electrode thick portion 2 on a point and the like in consideration of the cutting pitch as shown in FIG. can get.

[0016]

Embodiment 2 (Configuration) FIG. 7 is a perspective view of a vibrator portion of an ultrasonic probe according to the present embodiment, and FIG. 8 is a cross section of a mirror type ultrasonic probe using the vibrator. FIG. The basic configuration of this embodiment is the same as that of the first embodiment. The same components are denoted by the same reference numerals, and only the differences will be described.

In this embodiment, a silver electrode is applied to the main surface of the piezoelectric ceramic thin plate 1 in the same manner as in the first embodiment.
After drying, change the electrode thick part to another screen and apply.
After drying and baking, a laminated body of the acoustic matching layer, the piezoelectric element, and the back load material as shown in FIG. 5 of Example 1 was produced. Thereafter, a copper foil 15 having a thickness of 50 μm was adhered with a conductive adhesive, and a shape as shown in FIG. 7 was cut in a length direction by a precision cutting machine to produce a vibrator portion. The vibrator portion was mounted on a housing 12 provided with a mirror 16 for reflecting an ultrasonic wave via a polysulfone insulating plate 10, thereby producing an ultrasonic probe 17. For connection to the piezoelectric element 3, the electrode 5 a on the acoustic emission surface side is set to GND, dropped on the housing 12 with a conductive resin (adhesive) 9, connected to a coaxial cable from the housing 12 by a solder (not shown), and connected to the positive side. The electrode 5b has a configuration in which the signal line 11 is soldered to a copper foil 15 extending to the rear of the back load member 7 with solder 18 and is also molded with an epoxy resin 8 which also serves as insulation.

(Operation) Since the connection space can be minimized by manufacturing according to the above-described method, the ratio of the piezoelectric element 3 of the mirror-type ultrasonic probe vertically installed can be increased. Also, the process of manufacturing the vibrator portion is easier than manufacturing an ultrasonic probe using disk-shaped ceramics, and several tens of devices can be manufactured at a time. Further, since the acoustic matching layer 6 is laminated on the piezoelectric element 3 and then cut, the acoustic matching layer 6 having a desired thickness and a uniform thickness and the same shape as the piezoelectric element 3 can be manufactured. Further, after laminating the acoustic matching layer 6 and the back load material 7 on the piezoelectric element 3, the piezoelectric element 3 is cut, and a side electrode is provided. There is no wrap around.

(Effect) Since the acoustic matching layer 6 is laminated on the piezoelectric element 3 and then cut, an acoustic matching layer 6 having a desired thickness and uniform thickness, the same shape as the piezoelectric element 3 is obtained, and An ultrasonic probe having higher sensitivity than the ultrasonic probe and having no distortion of the ultrasonic beam can be manufactured. Another factor for improving the sensitivity is that the space for the connection is small and the ratio of the piezoelectric element 3 can be increased. And
The process of manufacturing the vibrator portion is much easier than manufacturing an ultrasonic probe using disk-shaped ceramics. After the acoustic matching layer 6, the piezoelectric element 3, and the back load material 7 are laminated, the vibrator is cut and vibrated. Since the probe part is manufactured, several tens of pieces can be manufactured at a time, and an ultrasonic probe can be manufactured at low cost from the viewpoint of mass production. In this embodiment, the acoustic matching layer 6 has a single-layer structure, but the same effect can be obtained if at least one acoustic matching layer 6 or acoustic lens is provided.

[0020]

Embodiment 3 (Structure) FIG. 9 is a sectional view of a transducer portion of an ultrasonic probe according to this embodiment. The basic configuration of this embodiment is the same as that of the first embodiment. The same components are denoted by the same reference numerals, and only the differences will be described.

In this embodiment, a laminated body of the acoustic matching layer 6, the piezoelectric element 3, and the back load material 7 is manufactured in the same manner as in the first embodiment, and after being cut, as shown by a broken line in FIG. The electrodes 5a,
The silver external electrode 21 is deposited on the side surface portion where
a and 21b were formed. However, the vibrator of this embodiment is
This is a configuration in which an epoxy resin-based acoustic lens 20 is formed on the piezoelectric element 3. An ultrasonic probe having the same configuration as that of FIG. 6 of the first embodiment was manufactured using the vibrator portion on which the external electrodes 21a and 21b were formed.

(Operation) When manufactured by the above-described method, it is possible to connect the external electrodes 21a and 21b formed on the side surfaces of the piezoelectric element electrically connected to the electrodes 5a and 5b of the piezoelectric element 3 by using a conductive resin. Becomes

(Effect) Even if the frequency is increased and the size is reduced and the width of the vibrator is reduced, an ultrasonic probe having high reliability for connection can be manufactured because the area required for conduction is increased. .

[0024]

Embodiment 4 (Structure) FIG. 10 is a perspective view of a transducer portion of an ultrasonic probe according to this embodiment. The basic configuration of this embodiment is the same as that of the first embodiment. The same components are denoted by the same reference numerals, and only the differences will be described.

In this embodiment, after cutting to expose the electrode thick portion, the two flexible substrates 22 that have been laminated into one piece from the middle are cut into the positive and negative electrodes 5a and 5a, respectively.
5b by soldering with a solder 18 and an adhesive 2
The ultrasonic probe is fixed to the vibrator by using 3 and cut in the length direction, mounted on a housing, and connected to a cable.

(Function) When the ultrasonic probe is manufactured by the above-described method, the ultrasonic probe can be manufactured without connecting the cable to the inside of the housing serving as the hard portion.

(Effect) When manufactured by the above-described method, there is no need to connect the cable to the hard portion, and the length of the hard portion can be shortened, and the commercial value is improved. The same effect can be obtained even if the connection with the flexible substrate 22 is performed not only by the solder 18 but also by a conductive resin.

[0028]

As described above, according to the ultrasonic probe and the method of manufacturing the same according to the present invention, the ultrasonic transducer of a piezoelectric element having a reduced thickness due to a demand for high frequency, small size and small diameter. In addition, a method of connecting the transducers, that is, a so-called electrode mounting method, is easy, and a highly reliable and inexpensive ultrasonic probe can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a piezoelectric element of an ultrasonic probe according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a piezoelectric element of the ultrasonic probe according to the first embodiment.

FIG. 3 is a perspective view showing another method for forming the thick electrode portion of the first embodiment.

FIG. 4 is a perspective view illustrating a method of manufacturing a transducer unit of the ultrasonic probe according to the first embodiment.

FIG. 5 is a perspective view illustrating a method of manufacturing the transducer unit of the ultrasonic probe according to the first embodiment.

FIG. 6 is a cross-sectional view showing the ultrasonic probe according to the first embodiment.

FIG. 7 is a perspective view illustrating a vibrator portion of an ultrasonic probe according to a second embodiment of the present invention.

FIG. 8 is a sectional view of an ultrasonic probe using the transducer of the ultrasonic probe according to the second embodiment.

FIG. 9 is a cross-sectional view illustrating a transducer section of an ultrasonic probe according to a third embodiment of the present invention.

FIG. 10 is a perspective view showing a transducer unit of an ultrasonic probe according to a fourth embodiment of the present invention.

FIG. 11 is a sectional view showing a conventional ultrasonic probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric ceramic thin plate 2a, 2b Electrode thick part 3 Piezoelectric element 5a, 5b electrode 6 Acoustic matching layer 7 Back load material 9 Conductive resin 10 Insulating plate 11 Signal line 12 Housing 17 Ultrasonic probe 18 Solder 20 Acoustic lens 21 External electrode 22 Flexible board

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 17/00 330 A61B 8/00 G01N 29/24

Claims (2)

(57) [Claims] 1. An ultrasonic probe comprising at least one or more acoustic matching layers or acoustic lenses, a piezoelectric element having electrodes on the front and back surfaces, and a back load material, wherein one end of the piezoelectric element And a front non-electrode portion provided on the front surface, the other end of the piezoelectric element, a rear non-electrode portion provided on the back surface, and the other end of the piezoelectric element, A surface electrode thick portion that is provided at an opposite position and is exposed from the side surface of the other end of the piezoelectric element, and is provided at a position that is the one end of the piezoelectric element and that faces the surface non-electrode portion; And a back electrode thick portion exposed from the side surface of the one end of the piezoelectric element. 2. An ultrasonic probe according to claim 1, comprising at least one or more acoustic matching layers or acoustic lenses, a piezoelectric element having electrodes on the front and back surfaces, and a back load material. After laminating and joining at least one or more acoustic matching layers or acoustic lenses and a back load member, the exposed surface electrode thick portion and the back electrode thick portion are cut and exposed, and the exposed surface electrode thick portion is exposed. And a connection at a thick portion of the back electrode and the back electrode.