TWI693731B - High-frequency ultrasound piezoelectric element, manufacturing method thereof and the high-frequency ultrasound probe comprising the high-frequency ultrasound piezoelectric element - Google Patents

Abstract

The present invention relates to a manufacturing method of the high-frequency ultrasound piezoelectric element, comprising: preparing bottom electrode by coating the complex of sol-gel solution and piezoelectric powder to the bottom electrode with spray method, sintering the coated complex to form a piezoelectric film, and forming an upper electrode on the piezoelectric film. The present invention produces the high-frequency ultrasound piezoelectric element by such an easy method and also get clearer ultrasound image than the prior art.

Description

High-frequency ultrasonic piezoelectric element, its manufacturing method and high-frequency ultrasonic piezoelectric element Frequency ultrasonic probe

The present invention relates to a high-frequency ultrasonic piezoelectric element, a method for manufacturing the same, and a high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element, and particularly to a high-frequency ultrasonic piezoelectric element including a piezoelectric film formed by a spray method, Manufacturing method and high-frequency ultrasound probe (high-frequency ultrasound probe) including the high-frequency ultrasound piezoelectric element.

Conventionally, an ultrasonic probe or the like is used to irradiate ultrasonic waves into an organism or the like to obtain a reflected wave from the inside of the organism, and the resulting reflected wave is signal-processed and visualized to diagnose the properties of the organism. A piezoelectric element is used for the transmission and reception of ultrasonic waves. As the material of the piezoelectric element, an oxide-based piezoelectric material having a perovskite crystal structure such as lead zirconate titanate (Pb(Zr,Ti)O ₃ :PZT) is generally used. Piezoelectric elements are usually manufactured by molding powder made of PZT into a predetermined shape such as a cube, sintering the molded body to obtain a ceramic sintered body, and then processing the sintered body as a piezoelectric film by cutting, grinding, etc. In a desired shape, an electrode is mounted on the piezoelectric film to form a piezoelectric element (for example, refer to Patent Document 1 and the like).

In recent years, it has been required to obtain ultrasound images with higher definition. High-definition ultrasound images require piezoelectric elements that can send and receive ultrasound at higher frequencies. When the same material is used as the material of the piezoelectric element, as the thickness of the piezoelectric film decreases, it becomes possible to transmit and receive ultrasonic waves at a high frequency. Specifically, the driving frequency of the piezoelectric element is inversely proportional to the thickness of the piezoelectric element. When a piezoelectric element having a 100 μm piezoelectric film is driven at, for example, 20 MHz, if the piezoelectric element made of the same material is used A piezoelectric film with a thickness of one-fifth of 100 μm, that is, 20 μm, usually has a driving frequency that is 5 times that of 20 MHz, that is, 100 MHz. If a piezoelectric element driven at such a high frequency of 100 MHz is used, the spatial resolution of the obtained ultrasound image in the irradiation direction is five times that of the case where the driving frequency is 20 MHz. Therefore, in order to obtain a piezoelectric element capable of obtaining a higher-definition ultrasonic image, it is necessary to form a piezoelectric film with a smaller thickness.

Prior technical literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. H07-45124.

However, as described above, the thinning of the sintered body made of PZT by mechanical processing such as cutting and grinding is inefficient, and the thinness of the resulting thin film is also limited. Furthermore, if a sintered body made of PZT having a thickness of several tens to hundreds of μm is machined, cracks and the like may occur.

The present invention was made in view of the above-mentioned problems, and its object is to form a thinner piezoelectric film by a simple method, and use the resulting piezoelectric film to obtain a high-frequency ultrasonic piezoelectric element capable of transmitting and receiving high-definition ultrasonic images.

In order to achieve the above object, the present invention applies a spray method to apply a composite of a sol-gel solution and piezoelectric powder on an electrode to form a piezoelectric film, thereby manufacturing a high-frequency ultrasonic piezoelectric element.

Specifically, the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention is characterized by comprising: a step of preparing a lower electrode; a composite body containing a sol-gel solution and a piezoelectric powder is coated on the lower electrode by spray coating Sintering the coated composite to form a piezoelectric film; and forming an upper electrode on the piezoelectric film.

According to the manufacturing method of the high-frequency ultrasonic piezoelectric element according to the present invention, a composite body containing a sol-gel solution and a piezoelectric powder is coated on the lower electrode by spraying method, so by appropriately adjusting the discharge amount of the composite body discharged , Discharge time, etc., it is possible to easily form a piezoelectric film of a desired film thickness in a desired area, and it is also possible to form an extremely thin piezoelectric film of several μm.

In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming the upper electrode, the piezoelectric film may be provided with a plurality of openings arranged in an array and exposing the piezoelectric film The mask, covering the piezoelectric film and the mask to form the upper electrode, and then removing the mask.

Thus, the upper electrodes are formed in an array on the piezoelectric film, so the resulting piezoelectric element can be applied to a so-called phased array type ultrasonic probe, which can control a plurality of upper electrodes The regions of the piezoelectric film directly below each other emit ultrasonic waves with a certain time difference, and electronic scanning is used to obtain a cross-sectional image inside the organism.

In this case, in the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction on the surface can be prepared; in the step of forming the piezoelectric film, the piezoelectric film is formed on the bottom surface of the concave portion; In the electrode step, the piezoelectric film is formed Plural upper electrodes aligned in the extending direction of the recess.

As a result, a plurality of upper electrodes are arranged in the recessed portion of the lower electrode along the extending direction of the recessed portion (the longitudinal direction of the lower electrode), so that the super-emission from each region of the piezoelectric film located directly under these upper electrodes can be suppressed and concentrated The sound wave diffuses in a direction perpendicular to the extending direction of the concave portion (width direction of the lower electrode). Therefore, when the piezoelectric element is used in an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced and the manufacturing cost can be reduced.

In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming a piezoelectric film, a mask having a plurality of openings arranged in an array and exposing the lower electrode may be arranged on the lower electrode, Then, the composite body is coated on the lower electrode by spray coating, and the composite body is sintered to form a plurality of piezoelectric films arranged in an array.

Thus, a plurality of thin piezoelectric films arranged in an array can be easily formed on the lower electrode. In addition, since a plurality of thin piezoelectric films can be formed in an array, the resulting piezoelectric element can be applied to a so-called phased array type superprobe. This ultrasonic probe can control a plurality of piezoelectric films to emit ultrasound at a specific time difference with each other. Acoustic wave, using electronic scanning to obtain a cross-sectional image of the inside of the organism.

In this case, in the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction on the surface may be prepared; in the step of forming the piezoelectric film, the bottom surface of the concave portion of the lower electrode is formed to be arranged along the A plurality of piezoelectric films arranged in the extending direction of the concave portion.

As a result, a plurality of piezoelectric films are arranged on the bottom surface of the concave portion of the lower electrode along the extending direction of the concave portion (the longitudinal direction of the lower electrode), and therefore it is possible to suppress and condense the ultrasonic waves emitted from the piezoelectric film perpendicular to the extending direction of the concave portion In the direction of (the width direction of the lower electrode). Therefore, when the piezoelectric element is used in an ultrasonic probe, there is no need to provide an acoustic lens, and the number of parts can be reduced Reduce manufacturing costs.

In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of preparing the lower electrode, a rod-shaped lower electrode having a concave portion on the end surface may be prepared; in the step of forming the piezoelectric film, on the bottom surface of the concave portion of the lower electrode A piezoelectric film is formed.

As a result, the piezoelectric film is formed on the bottom surface of the concave portion on the end surface of the rod-shaped lower electrode. Therefore, it is possible to suppress and condense the diffusion of ultrasonic waves emitted from the piezoelectric film from the axial direction of the rod-shaped lower electrode to the outside. Therefore, as in the case described above, when the piezoelectric element is used in an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced and the manufacturing cost can be reduced. In addition, by providing, for example, a single piezoelectric film on the end surface of the rod-shaped lower electrode, it can be applied to a so-called single-vibrator ultrasonic probe that can obtain a cross-sectional image of the inside of an organism by mechanical scanning, instead of the above-mentioned phased array ultrasonic Probe.

In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, a piezoelectric powder made of PZT can be used as the piezoelectric powder.

The high-frequency ultrasonic piezoelectric element according to the present invention is characterized in that it is obtained by the above-mentioned manufacturing method, is provided with a lower electrode, and a composite body containing a sol-gel solution and a piezoelectric powder is coated on the lower electrode by spraying and then sintered The formed piezoelectric film and the upper electrode formed on the piezoelectric film.

According to the high-frequency ultrasonic piezoelectric element according to the present invention, since the piezoelectric film formed by coating the composite containing the sol-gel solution and the piezoelectric powder by the spray coating method is included, the film of the piezoelectric film can be easily adjusted If it is thick, it is easy to obtain a thin piezoelectric film. Therefore, since it has a thin piezoelectric film, it is easy to obtain a high-frequency ultrasonic piezoelectric element capable of transmitting and receiving ultrasonic waves of higher frequencies.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the upper electrode may be formed in a plurality of arrays on the piezoelectric film.

As a result, the upper electrodes are arranged in an array on the piezoelectric film, so the resulting piezoelectric element can be applied to a so-called phased array ultrasonic probe. This ultrasonic probe controls the piezoelectrics located directly below a plurality of upper electrodes Each area of the membrane emits ultrasonic waves with a certain time difference from each other, and a cross-sectional image inside the organism can be obtained by electronic scanning.

In this case, the lower electrode is plate-shaped and has a concave portion extending in the longitudinal direction on its surface, the piezoelectric film is formed on the bottom surface of the concave portion, and a plurality of upper electrodes can be arranged on the piezoelectric film along the extending direction of the concave portion.

As a result, the plurality of upper electrodes are arranged in the recessed portion of the lower electrode along the extending direction of the recessed portion (the longitudinal direction of the lower electrode), so that the super-emission from each region of the piezoelectric film located directly under these upper electrodes can be suppressed and concentrated The sound wave diffuses in a direction perpendicular to the extending direction of the concave portion (width direction of the lower electrode). Therefore, when the piezoelectric element is used in an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced and the manufacturing cost can be reduced.

In the high-frequency ultrasonic piezoelectric element according to the present invention, a plurality of piezoelectric films may be formed in an array on the lower electrode.

Thus, since a plurality of piezoelectric films are formed in an array, it can be applied to a so-called phased array ultrasonic probe, which controls a plurality of piezoelectric films to emit ultrasonic waves with a specific time difference from each other, which can be used Electronic scanning obtains a cross-sectional image inside the organism.

In this case, the lower electrode is plate-shaped and has a concave portion extending in the longitudinal direction on its surface, and a plurality of piezoelectric films may be arranged along the extending direction of the concave portion and arranged on the bottom surface of the concave portion of the lower electrode.

As a result, a plurality of piezoelectric films are arranged on the bottom surface of the concave portion of the lower electrode along the extending direction of the concave portion (the longitudinal direction of the lower electrode), and therefore it is possible to suppress and condense the ultrasonic waves emitted from the piezoelectric film perpendicular to the extending direction of the concave portion In the direction of (the width direction of the lower electrode). Therefore, when the piezoelectric element is used in an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced and the manufacturing cost can be reduced.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the lower electrode is rod-shaped and has a concave portion at its end surface, and the piezoelectric film may be formed on the bottom surface of the concave portion.

As a result, the piezoelectric film is formed on the bottom surface of the concave portion on the end surface of the rod-shaped lower electrode. Therefore, it is possible to suppress and condense the diffusion of ultrasonic waves emitted from the piezoelectric film from the axial direction of the rod-shaped lower electrode to the outside. Therefore, as in the case described above, when the piezoelectric element is used in an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced and the manufacturing cost can be reduced. In addition, by providing, for example, a single piezoelectric film on the end surface of the rod-shaped lower electrode, it can be applied to a so-called single-vibrator ultrasonic probe that can obtain a cross-sectional image of the inside of an organism by mechanical scanning, instead of the above-mentioned phased array ultrasonic Probe.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the piezoelectric powder may be a piezoelectric powder made of PZT.

The high-frequency ultrasonic probe according to the present invention is characterized by including the above-mentioned high-frequency ultrasonic piezoelectric element.

According to the high-frequency ultrasonic probe according to the present invention, since the high-frequency ultrasonic piezoelectric element having the above-mentioned functions and effects is included, a thinner piezoelectric film can be easily obtained and high-frequency ultrasonic waves can be transmitted and received. As a result, more High definition image.

High-frequency ultrasonic piezoelectric element according to the present invention, and its manufacture Method, and a high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element, a composite body containing a sol-gel solution and a piezoelectric powder is coated on the lower electrode by a spray coating method, so an extremely thin piezoelectric film can be obtained simply, As a result, higher frequency ultrasonic waves can be transmitted and received, and a high-frequency ultrasonic probe capable of obtaining higher-definition images can be obtained.

10, 20, 30‧‧‧ High frequency ultrasonic piezoelectric element

11, 21, 31‧‧‧ Lower electrode

12, 22, 32‧‧‧ Piezo film

13‧‧‧Mask layer

14‧‧‧ opening

15, 25, 35‧‧‧ Upper electrode

26、36‧‧‧recess

1(a) to (f) are cross-sectional views sequentially showing the manufacturing process of the high-frequency ultrasonic piezoelectric element according to Embodiment 1 of the present invention.

2 is a plan view showing a high-frequency ultrasonic piezoelectric element according to Embodiment 1 of the present invention.

3 is a cross-sectional view showing a high-frequency ultrasonic piezoelectric element according to a modification of Embodiment 1 of the present invention.

4(a) is a cross-sectional view showing a high-frequency ultrasonic piezoelectric element according to Embodiment 2 of the present invention, and (b) is a plan view showing a high-frequency ultrasonic piezoelectric element according to Embodiment 2 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

Example 1

Hereinafter, the manufacturing method and the configuration of the high-frequency ultrasonic piezoelectric element 10 according to Embodiment 1 of the present invention will be described with reference to FIGS. 1(a) to (f) and FIG. 2.

First, as shown in FIG. 1(a), a flat plate-shaped lower electrode 11 is prepared. The material of the lower electrode 11 is not particularly limited as long as it is a conductive material composed of a metal generally used as an electrode. In addition, the thickness of the lower electrode 11 is also not particularly limited, as long as it is appropriately selected from the viewpoint of miniaturization and strength of the piezoelectric element, for example, 10 μm to 150 μm.

Next, as shown in FIG. 1( b ), a piezoelectric film 12 is formed on the lower electrode 11. The piezoelectric film 12 is obtained by applying a composite body containing a sol-gel solution and a piezoelectric powder on the lower electrode 11 using a spray coating method, and sintering the applied composite body. For example, the sol-gel solution is obtained by dissolving a metal alkoxide in a solvent such as ethanol or methanol, and it is preferable to use a PZT sol-gel solution containing lead alkoxide, zirconium alkoxide, and titanium alkoxide. In addition, PZT can be used as the material of the piezoelectric powder. The composition ratio (weight ratio) of the sol-gel solution to the piezoelectric powder may be, for example, sol-gel solution: piezoelectric powder=1:1-2:1. In addition, the particle size of the piezoelectric powder is preferably 50 to 1000 nm. The discharge amount, discharge time, and distance from the discharge to the lower electrode of the composite in the spray coating method can be appropriately changed according to the film thickness of the formed piezoelectric film. In order to obtain a piezoelectric element that can transmit and receive ultrasonic waves of higher frequencies, the piezoelectric film can be thinned. If the spraying method is used, it can be easily thinned by controlling the discharge amount or discharge time of the composite, for example, in Under the condition that the discharge time is 200 ms, a composite layer with a thickness of about 10 μm can be formed. After coating by this spray coating method, the composite layer is dried at about 150°C for 5 minutes, temporarily sintered at about 450°C for 5 minutes, and fired at about 650°C for 5 minutes, and then, for example, by using electricity Corona discharge is subjected to polarization treatment to obtain piezoelectric film 12.

Next, as shown in FIG. 1( c ), a mask layer 13 is provided on the piezoelectric film 12. The material of the mask layer 13 may use materials such as resin, glass, wood, or paper, but is not limited thereto.

Next, as shown in FIG. 1( d ), a plurality of openings 14 that expose the piezoelectric film 12 are formed on the mask layer 13. The openings 14 are provided at positions where the upper electrode 15 needs to be formed later, and in this embodiment are arranged at equal intervals along the longitudinal direction of the lower electrode. The formation of the opening 14 depends on the material of the mask layer 13 and may be chemically treated such as an etching method or mechanically treated such as cutting. In addition, in this embodiment, the opening 14 is formed after the mask layer 13 is provided on the piezoelectric film 12, but it may be Before the mask layer 13 is provided on the piezoelectric film 12, an opening 14 is formed in the mask layer 13 in advance, and then the mask layer 13 with the opening 14 formed is disposed on the piezoelectric film 12.

Next, as shown in FIG. 1( e ), the upper electrode 15 is formed on the piezoelectric film 12 and the mask layer 13. The material of the upper electrode 15 is not particularly limited as long as it is a conductive material generally used as an electrode, and for example, metals such as gold and silver can be used. In addition, conventional methods such as a vapor deposition method and a sputtering method can be used to form the upper electrode 15. The thickness of the upper electrode 15 is also not particularly limited, as long as it is appropriately selected from the viewpoint of miniaturization and strength of the piezoelectric element, for example, 10 μm to 150 μm.

Next, as shown in FIG. 1( f ), the mask layer 13 is removed so that the upper electrode 15 remains only on the piezoelectric film 12 in the opening 14. Although not shown, the high-frequency ultrasonic piezoelectric element 10 of this embodiment can be obtained by connecting the leads connected to the power source to the lower electrode 11 and the plurality of upper electrodes 15 respectively.

For convenience, FIG. 1 shows that three openings 14 are formed on the mask layer 13 and three upper electrodes 15 are formed, but of course it is not limited to this, and five upper electrodes may also be formed as shown in FIG. 2 15. It is also possible to form five or more upper electrodes 15 as required. In this embodiment, a plurality of upper electrodes 15 are formed in an array on the piezoelectric film 12. Specifically, as shown in FIGS. 1( f) and 2, the upper electrodes 15 are arranged along the longitudinal direction of the lower electrode 11 . Thus, by using a high-frequency ultrasonic piezoelectric element 10 in which an upper electrode 15 is arranged in an ultrasonic probe for imaging a cross section inside an organism, a so-called phased array type ultrasonic probe can be obtained. The ultrasonic probe controls the timing of applying the voltage to the upper electrode so that the regions of the piezoelectric film directly below the upper electrodes emit ultrasonic waves with a specific time difference from each other, so that the cross-sectional image inside the organism can be obtained by electronic scanning. The high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element of this embodiment is the same as the conventional ultrasonic probe, and is attached from the base end side to the front end side on the probe body The backing material, the piezoelectric element of the present embodiment, the acoustic matching layer and the acoustic lens (acoustic lens) are arranged in a secondary configuration. However, in the high-frequency ultrasonic probe of this embodiment, the base material and the acoustic matching layer are not essential structures.

In addition, in this embodiment, as shown above, a plurality of upper electrodes are formed on the piezoelectric film formed by covering the lower electrode using a mask having openings, but a mask having openings formed in an array may also be used. A plurality of piezoelectric films arranged in an array are formed on the lower electrodes, and upper electrodes are formed on the plurality of piezoelectric films. Thereby, when the piezoelectric film material is sprayed, a plurality of piezoelectric films are separated from each other, so there is no need to perform a cutting process of dicing the piezoelectric film in order to prevent crosstalk in the piezoelectric element. In particular, since the cutting of the thin piezoelectric film is prone to cracks and the like is difficult to perform, it is advantageous in this regard.

In this embodiment, a flat plate-shaped lower electrode 11 is used to produce a high-frequency ultrasonic piezoelectric element 10. However, a plate-shaped lower electrode having a recess extending in the longitudinal direction on the surface may be used, and a piezoelectric film and an upper electrode may be formed in the recess , Thereby forming a high-frequency ultrasonic piezoelectric element. A high-frequency ultrasonic piezoelectric element of this form will be described as a modification of Embodiment 1 with reference to FIG. 3. In this embodiment, the description of the same points as in Embodiment 1 is omitted, and only the differences are described in detail. In addition, FIG. 3 is a diagram showing an ultrasonic piezoelectric element equivalent to the high-frequency ultrasonic piezoelectric element shown in FIG. 2 except that the lower electrode has a recess, and particularly shows a cross section along the longitudinal direction of the upper electrode on one of the upper electrodes. That is, in the high-frequency ultrasonic piezoelectric element of this modification, a plurality of upper electrodes are arranged in a direction perpendicular to the paper surface of FIG. 3.

As shown in FIG. 3, the high-frequency ultrasonic piezoelectric element 20 of this modification includes a lower electrode 21 having a recess 26 formed on the surface. The recess 26 is formed to extend in the longitudinal direction of the lower electrode 21. In addition, the periphery of the opening of the recess 26 (the boundary between the surface of the lower electrode 21 and the recess 26) is chamfered (rounding). A piezoelectric film 22 is formed on the bottom surface of the recess 26 of the lower electrode 21. The piezoelectric film 22 is formed along the shape of the bottom surface of the recess 26. The upper electrode 25 is formed on the piezoelectric film 22. As in the first embodiment, the upper electrode 25 is provided in plural along the longitudinal direction of the lower electrode 21, that is, along the extending direction of the concave portion. In addition, the high-frequency ultrasonic piezoelectric element 20 of this modified example can be formed in the same manner as the high-frequency ultrasonic piezoelectric element 10 of Embodiment 1 described above except that the lower electrode 21 having the recess 26 is used, and the formation of the piezoelectric film 22 and the upper electrode 25 is performed. Method.

In addition, in this modification, a plurality of piezoelectric films arranged in the extending direction of the concave portion are also formed on the lower electrode, and an upper electrode is formed on each of the plurality of piezoelectric films. Thus, as described above, when the piezoelectric film material is sprayed, a plurality of piezoelectric films are separated from each other, so there is no need to perform processing such as cutting off the piezoelectric film in order to prevent crosstalk in the piezoelectric element.

In the high-frequency ultrasonic piezoelectric element 20 of the present modification example, the surface of the lower electrode 21 is formed with a concave portion 26 extending parallel to the arrangement direction of the piezoelectric film 22, and therefore, it is possible to suppress and converge the piezoelectric film 22 disposed in the concave portion 26 The emitted ultrasonic wave diffuses in a direction perpendicular to the extending direction of the recess 26 (the width direction of the lower electrode 21). As a result, when the high-frequency ultrasonic piezoelectric element 20 is used in an ultrasonic probe, it is not necessary to provide an acoustic lens.

Example 2

Next, a high-frequency ultrasonic piezoelectric element 30 according to Embodiment 2 of the present invention will be described with reference to FIG. 4. In addition, in this embodiment, the description of the same points as those of the above-mentioned Embodiment 1 and one modification thereof is omitted, and only the differences are described in detail. The high-frequency ultrasonic piezoelectric element 30 of the present embodiment is different from the high-frequency ultrasonic piezoelectric element 10 of the first embodiment in that it uses a rod-shaped lower electrode 31 as a lower electrode and forms a single piezoelectric film 32 and an upper electrode 35. .

As shown in FIGS. 4(a) and (b), in the high-frequency ultrasonic piezoelectric element 30 of this embodiment, The lower electrode 31 has a rod shape as described above, and particularly has a cylindrical shape. In addition, one end surface of the lower electrode 31 is formed with a spherical segment shaped concave portion 36 having a circular opening. The periphery of the opening of the recess 36 (the boundary between the surface of the lower electrode 31 and the recess 36) is chamfered. For example, the diameter of the cross section of the lower electrode 31 is 10 mm, the opening diameter of the recess 36 is 6 mm, and the depth of the recess 36 is 2 mm. Of course, these dimensions are only an example and are not limited to these, and these dimensions may be appropriately selected.

A piezoelectric film 32 is formed on the bottom surface of the recess 36 of the lower electrode 31. The piezoelectric film 32 is formed along the shape of the bottom surface of the recess 36. In this embodiment, as in Embodiment 1, the piezoelectric film 32 can be formed by coating and sintering the composite body by spray coating. The upper electrode 35 is formed on the piezoelectric film 32. The upper electrode 35 is also formed along the shape of the bottom surface of the recess 36. In the high-frequency ultrasonic piezoelectric element 30 of this embodiment, before the upper electrode 35 is formed, a mask layer having a plurality of openings is not particularly formed, but a single film is formed on the piezoelectric film 32 by a method such as vapor deposition组合的第一 electrode35. In addition, although not shown, as in the first embodiment, the lower electrode 31 and the upper electrode 35 are respectively connected with leads connected to the power source.

In the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, the piezoelectric film 32 and the upper electrode 35 are formed on the end surface of the rod-shaped lower electrode 31, so it can be used for a single vibrator type that is used by mechanical scanning Ultrasonic probe. In addition, the high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element 30 of the present embodiment may have the same structure as the first embodiment described above. In addition, in the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, the piezoelectric film 32 and the upper electrode 35 are formed in the concave portion 36 formed on the end surface of the rod-shaped lower electrode 31, so the ultrasonic waves emitted from the piezoelectric film 32 are concentrated It does not diffuse outward from the axial direction of the lower electrode 31. As a result, when the high-frequency ultrasonic piezoelectric element 30 is used in an ultrasonic probe, it is not necessary to provide an acoustic lens.

As described above, according to the high-frequency ultrasonic piezoelectric element of the present invention, its manufacturing method, and the high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element, the lower electrode is coated with the sol-gel solution The composite of electropowder can easily obtain an extremely thin piezoelectric film, and as a result, can transmit and receive ultrasonic waves of higher frequencies, and can obtain a high-frequency ultrasonic probe capable of obtaining higher-definition images.

The embodiments of the present invention are not limited to the above-mentioned embodiments, and various changes can be made without departing from the gist of the present invention.

10‧‧‧High frequency ultrasonic piezoelectric element

11‧‧‧Lower electrode

12‧‧‧ Piezo film

13‧‧‧Mask layer

14‧‧‧ opening

15‧‧‧Upper electrode

Claims (13)

A method for manufacturing a high-frequency ultrasonic piezoelectric element, comprising the steps of: preparing a plate-shaped lower electrode having a concave portion extending on the surface in a longitudinal direction; coating the bottom surface of the concave portion of the lower electrode by spray coating A composite body containing a sol-gel solution and a piezoelectric powder, and the step of sintering the coated composite body to form a piezoelectric film; and forming a plurality of piezoelectric films arranged on the piezoelectric film to be arranged along the extending direction of the concave portion Steps of the upper electrode. The method for manufacturing a high-frequency ultrasonic piezoelectric element according to claim 1, wherein in the step of forming the upper electrode, the piezoelectric film is provided with a plurality of openings arranged in an array and exposing the piezoelectric film A mask, covering the piezoelectric film and the mask to form an upper electrode, and then removing the mask. A method for manufacturing a high-frequency ultrasonic piezoelectric element, comprising the steps of: preparing a plate-shaped lower electrode having a concave portion extending on the surface in a longitudinal direction; coating the bottom surface of the concave portion of the lower electrode by spray coating A composite body containing a sol-gel solution and a piezoelectric powder, a step of sintering the coated composite body to form a piezoelectric film; and a step of forming an upper electrode on the piezoelectric film; and forming the piezoelectric film In this step, a plurality of piezoelectric films arranged in a line along the extending direction of the concave portion are formed on the bottom surface of the concave portion of the lower electrode. The method for manufacturing a high-frequency ultrasonic piezoelectric element according to claim 3, wherein in the step of forming the piezoelectric film, the lower electrode is provided with an arrangement in an array Then, the masks of the plurality of openings exposed by the lower electrode are coated with the composite body on the lower electrode by a spray coating method, and the composite body is sintered to form a plurality of piezoelectric films arranged in an array. A method for manufacturing a high-frequency ultrasonic piezoelectric element, comprising the steps of: preparing a rod-shaped lower electrode having a concave portion at an end surface; applying a sol-gel solution and a sol-gel solution to the bottom surface of the concave portion of the lower electrode by spray coating In the piezoelectric powder composite, the step of sintering the applied composite to form a piezoelectric film; and the step of forming an upper electrode arranged on the piezoelectric film. The method for manufacturing a high-frequency ultrasonic piezoelectric element according to any one of claims 1 to 5, wherein a piezoelectric powder made of PZT is used as the above-mentioned piezoelectric powder. A high-frequency ultrasonic piezoelectric element, characterized by the high-frequency ultrasonic piezoelectric element manufactured by the method for manufacturing a high-frequency ultrasonic piezoelectric element of claim 1, the high-frequency ultrasonic piezoelectric element having: a plate having a concave portion extending in the longitudinal direction on the surface Shaped lower electrode; a piezoelectric film formed by coating a composite body containing a sol-gel solution and a piezoelectric powder on the bottom surface of the concave portion of the lower electrode by spraying and then sintering; and forming on the piezoelectric film A plurality of upper electrodes arranged along the extending direction of the concave portion. The high-frequency ultrasonic piezoelectric element according to claim 7, wherein the upper electrode is formed in a plurality of arrays on the piezoelectric film. A high-frequency ultrasonic piezoelectric element, characterized by the high-frequency ultrasonic piezoelectric element according to claim 3 A high-frequency ultrasonic piezoelectric element manufactured by a method for manufacturing a device, the high-frequency ultrasonic piezoelectric element including: a plate-shaped lower electrode having a concave portion extending on the surface in a longitudinal direction; and coating the bottom surface of the concave portion of the lower electrode by a spray coating method A plurality of piezoelectric films formed by sintering a composite body containing a sol-gel solution and a piezoelectric powder; and an upper electrode formed on the piezoelectric film; the plurality of piezoelectric films are arranged along the extending direction of the concave portion It is arranged on the bottom surface of the recess of the lower electrode. The high-frequency supersonic piezoelectric element according to claim 9, wherein a plurality of the piezoelectric films are formed in an array on the lower electrode. A high-frequency ultra-sonic piezoelectric element, characterized by a high-frequency ultrasonic piezoelectric element manufactured by the method for manufacturing a high-frequency ultrasonic piezoelectric element of claim 5, the high-frequency ultrasonic piezoelectric element having: a rod-shaped lower electrode having a concave portion at an end surface; A piezoelectric film formed by coating a composite body containing a sol-gel solution and a piezoelectric powder on the bottom surface of the concave portion of the lower electrode by spraying and then sintering; and an upper electrode formed on the piezoelectric film. The high-frequency ultrasonic piezoelectric element according to any one of claims 7 to 11, wherein the above-mentioned piezoelectric powder is made of PZT. A high-frequency ultrasonic probe characterized by including the high-frequency ultrasonic piezoelectric element according to any one of claims 7 to 12.

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