KR20030082303A - Ultrasonic transducer array - Google Patents

Abstract

The present invention relates to a medical imaging ultrasound transducer in a straight or curved form, wherein electrodes located on both sides of the piezoceramic are made of a flexible double sided connector having a flexible double sided connector, and the device density of the ultrasonic transducer ( greatly increase the element density, greatly reduce the noise by individual grounding of each device, greatly improve the ultrasonic utilization efficiency by using the concave acoustic lens whose sound wave transfer speed is faster in water, and improve the piezoelectric ceramic and matching layer A shielding layer deposited on the outside of the shield reduces electromagnetic interference (EMI) and achieves electrical shielding with the patient, while the shield provides mechanical and moisture protection.

In addition, the ground conductor of the flexible printed circuit board (insulated board) is made thicker than existing products to serve as a heat sink, thereby ensuring thermal reliability of the product and minimizing electromagnetic interference (EMI). will be.

Description

Ultrasonic transducer array

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical imaging ultrasound transducer in a straight or curved shape. In detail, electrodes located on both sides of a piezoceramic may be used in a flexible double sided connector having a flexible double sided connector. It greatly increases the element density, greatly attenuates the noise by individual grounding of each element, and greatly improves the ultrasonic utilization efficiency by using a concave acoustic lens whose sound wave transfer speed is faster than that of water. The shielding layer deposited on the outer side of the mating layer achieves electrical shielding with the patient, reduces electromagnetic interference (EMI), and the shielding layer achieves mechanical and moisture protection.

In addition, the ground conductor formed on the flexible printed circuit board (insulated board) is formed thicker than the existing product to serve as a heat sink, thereby ensuring thermal reliability of the product and minimizing electromagnetic interference (EMI). I did it.

Ultrasound imaging has been used in medicine for many years. Straight and curved ultrasound transducers are used to visualize the conditions in the patient's body. These ultrasound image transducers are also used in other areas. But medical imaging is probably the best known field for the use of these converters.

Typically, ultrasonic transducers for visualization images of certain images in the human body include ultrasonic oscillators arranged linearly. These ultrasonic oscillators are driven by a randomly generated stimulus (mainly an electrical signal), and receive reflected waves from various subjects.

In the advances in technology, there has been a need to produce ultrasound images with improved resolution. Of course, it includes not only better images, but also greater durability and ease of use and convenience.

In a typical array ultrasonic transducer, the piezoceramic is driven by a voltage applied to the electrode. Such linear ultrasonic transducers are generally formed of piezoceramic, which is placed between two layers of electrodes. The piezoceramic of this structure is fixed to a backing called a sound absorbing layer, which is cut into individual single elements along the longitudinal axis.

In manufacturing such piezoelectric ultrasonic transducers, one of the limiting factors is that as the device size of the transducer decreases, the difficulty in joining the wires for sending signals to the transducer increases. Such wire bonding is required for linear ultrasonic transducers with drive and probe circuits.

In addition, piezoceramic, which is one of the most important items of piezoelectric ultrasonic transducer, rises in and out of about 10 ° C compared to the pre-use temperature (room temperature) as the use time of the ultrasonic transducer increases, and the ground conductor Since the thickness is about 33 μm, sufficient heat dissipation is not achieved, which lowers the thermal reliability and efficiency of the product, as well as causing noise in the product due to electromagnetic interference (EMI).

Accordingly, the present invention provides a double-sided flexible circuit, a flex circuit or a connector in order to drive by applying a voltage to the electrode in contact with the surface of the piezoceramic, or to detect the vibration in the piezoceramic Used.

In addition, the present invention provides that the electrodes on both sides of the piezoceramic are connected to a double sided circuit or connector by soldering a flexible double sided connector to a ceramic electrode or through the use of an anisotropic conductive adhesive. do.

When the flexible double-sided connector is bonded to the piezoceramic electrode, the filled adhesive material (fill) is used to strengthen the strength of the bonding site. In the case of a soldering method, this filler means of course soldering. However, such filling may be additionally formed by screen printing or other processes. Anisotropic conductive adhesives may also be used to connect the flexible connector to the transducer.

Also, in the present invention, one of the first and second connector conductors is a common conductor commonly connected to the electrodes of the piezoceramic. The second connector conductor is in this case composed of an array of individual conductors connected to the elements of the piezoelectric transducer.

In addition, the present invention is that respective ground conductors are used to drive or sense an element of each piezoelectric transducer. Thus both sides of the flexible double-sided connector comprise separate electrodes for connecting the respective piezoelectric elements.

In addition, the element density of the ultrasonic transducer can be increased by using two flexible double-sided connectors connected to the electrodes of the piezoceramic, in which the conductors of each of the flexible double-sided connectors are all separate from the elements of the piezoelectric transducer. Can be connected.

As a result, an increase in the space provided in the flexible double-sided connector or an increase in the pitch of the conductive wires can eventually reduce the spacing of the individual conductors in the flexible double-sided connector. Thus, the relative space of each connector wiring is increased by corresponding to the converter element. This can be done in two ways.

And, since the registration is maintained between the first and second conductive contacts, the two contacts of the ultrasonic single device are defined from a flexible circuit or a double-sided connector on one side.

In addition, by displacing the first and second patterns of a single flexible double-sided connector, each circuit element is connected using the first flexible double-sided connector, and the second terminal is connected using another second flexible double-sided connector. .

According to the present invention, through the use of the individual ground conductor of the above structure, each piezoelectric element has an individual ground on the opposite side (the back layer side) of the piezoelectric ceramic. This may help to reduce noise, depending on the drive system used.

In addition, the present invention has several features that can improve the performance of the ultrasonic transducer. A concave acoustic lens is used for ultrasound focusing in the lateral direction when the propagation speed in the lens is larger than in water. The lens is made of epoxy, whose sound speed is faster than 1700 m / s.

Water, on the other hand, has a sound velocity of about 1500 m / s. A shielding layer is deposited on the outside of the piezoelectric ceramic and matching layer, which not only reduces electromagnetic interference (EMI) but also electrically shields the patient from the sensor.

The thickness of the shielding film does not affect the attenuation of the ultrasonic signal and should be such that it can suppress electromagnetic interference. This shielding film is preferably deposited so as to surround 100% of both sides and the surface of the transducer.

Furthermore, the transducer in the present invention also has a protective film that surrounds both sides of the piezoceramic. This protects the bonding portion of the matching layer and the piezoelectric ceramic and the bonding portion of the piezoelectric ceramic and the back layer.

In addition, the present invention is electroless plating or chemical vapor deposition (Physical Vapor Deposition) or physical vapor deposition (Electric Vapor Deposition) or the adhesion of the conductive material to the thickness of the ground conductor of the flexible printed circuit board And the like to form thicker than the thickness of the existing ground conductor.

In general, as the ultrasonic transducer is driven, the temperature of the piezoelectric element, which is a core component of the ultrasonic transducer, is increased, thereby deteriorating the transducer characteristics. Therefore, heat dissipation devices such as heat sinks are required to maintain the unique characteristics of the converter.

Due to this necessity, if the thickness of the grounding conductor is formed thicker than the existing product, thermal reliability can be ensured, which may help to maintain the unique characteristics of the ultrasonic transducer.

At the same time, the increased thickness of the ground conductor encapsulates the ultrasonic transducer, thus reducing noise from the outside, which will help minimize electromagnetic interference (EMI).

1 is a cross-sectional view of the converter proposed in the present invention.

2: Schematic diagram of a linear array ultrasonic transducer.

3 is a partial cross-sectional view of the present invention piezoceramic.

4 is an enlarged view of FIG. 1 to better show a portion in which a flexible double-sided connector applied to the present invention is connected to a piezoelectric ceramic. FIG.

5 is a partial plan view showing the lower surface and the electrode of the present invention piezoceramic.

6 is a view showing another connection method of the flexible double-sided connector of the present invention.

7 is a view showing a connection method of two flexible double-sided connectors to increase the pattern pitch of the electrode in the present invention.

8 is a schematic diagram showing how several transducer elements in the present invention are connected to a plurality of wires of the connector conductor of the first layer.

<Explanation of symbols for the main parts of the drawings>

(10)-Array Ultrasonic Transducers (10a to 10k) (20a to 20e)-Elements of Ultrasonic Transducers

(12)-piezoelectric ceramic (14)-conductive coating

(15)-Dicing Step (16) (17)-Insulation Stage

(18) (20)-electrode 18a-18d (20a-20d)-electrode of transducer element

(22) (22a) (22b)-flexible double-sided connector

(24)-Insulation Board (24I)-Insulation

(26) (26a--26d)-Ground connector conductor

(28) (28a ~ 28d)-Signal Connector Conductors

(26E) (28E) (40) (41)-contact

(30)-Acoustic layer (backing) (31)-Adhesive

(32) (33)-Matching layer (34)-Sound focusing element

(34P)-Protection Unit (36)-Shields

(38)-Protection (42)-Filling Part

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic diagram for defining the transverse and longitudinal directions of the arrayed ultrasonic transducer 10 used in the present invention.

The ultrasonic transducer 10 has a plurality of ultrasonic transducer elements 10a to 10k, and the longitudinal direction is a direction in which the tenth element 10k, which is an ultrasonic transducer element, is arranged, and the lateral direction is an orthogonal direction thereto. to be.

Referring to FIG. 3, which shows a piezoceramic 12, the piezoceramic 12 is coated (or coated) with a suitable conductive coating 14, such as a conductor such as gold, copper, silver, aluminum. . The conductive coating 14 is formed of the electrodes 18, 20 so that the piezoceramic 12 is surrounded by the first and second electrodes 18, 20.

Insulating ends 16 and 17 formed on the conductive coating 14 may electrically separate the first and second electrodes 18 and 20. The insulating ends 16 and 17 may be formed by any suitable process including dicing or corrosion.

In the present invention, the flexible double-sided connector 22 is used to connect from the piezoceramic transducer elements 10a to 10k to the driving or sensing circuit, and this technique is a technique generally found in this field. Is one of.

5 to 7, the piezoceramic 12 and the conductive coating 14 are generally divided into a dicing step 15, and the dicing step 15 is a converter element 10. A plurality of ultrasonic transducer elements 10a to 10k are produced along the longitudinal direction of.

This technique is well known in this field, and in general, the piezoceramic 12, which has been subjected to a conductive coating, is a sound absorbing layer 30, or a matching layer 32, 33 using a suitable adhesive 31. Applied after adhering to

In the present invention, the flexible double-sided connector 22 must be fixed to the piezoceramic 12 and the coated electrodes 18 and 20 before the piezoceramic 12 coated with the conductive material is adhered to the sound absorbing layer 30. do. This is explained in the next section. When the fixing step is completed, the piezoelectric ceramics 12 coated with the conductive coating are adhered to the sound absorbing layer 30 using a suitable adhesive 31.

The structure of the ultrasonic transducer described in the present invention is composed of one inner matching layer 32, an outer matching layer 33, and an acoustic focusing element 34. The acoustic focusing element 34 is formed of the acoustic focusing element 34, the internal and external matching layers 32 and 33, the piezoelectric ceramics 12 coated with a conductive material, and all or part of the sound absorbing layer 30. It consists of a protection part 34P which protects along a circumference. As such, the protection portion 34P of the acoustic focusing element 34 protects the ultrasonic transducer structure from mechanical shock and moisture, thereby preventing each layer from being separated.

The acoustic focusing element 34 of the present invention is a concave acoustic lens having a sound velocity faster than that of water. The acoustic focusing element 34 forms a concave acoustic lens with epoxy having a sound wave speed of 1700 m / s or faster or about 2000 m / s, which is actually compared with a propagation speed of 1500 m / s in water. do. Since the sound wave propagation speed in the concave acoustic lens is faster than the sound wave propagation speed in the water, the concave acoustic lens has an effect of focusing acoustic energy at a focal point determined by the radius of curvature.

In the present invention, the shielding film 36 is formed on the front and side surfaces of the transducer element by the deposition of a suitable metallic electromagnetic shielding film. The shielding film 36 lowers the sensitivity of the electromagnetic interference of the transducer to improve the sensitivity (sensitivity), and also electrically insulates the ultrasound transducer from the patient. In addition, the shielding film 36 prevents damage due to impact or effectively blocks moisture, thereby preventing structural damage of the ultrasonic transducer associated with moisture.

The protective film 38 is covered with a thin film on the shielding film 36 to cover the layer structure of the transducer to protect it from moisture and mechanical shock.

Details of the flexible double-sided connector used in the present invention are shown in FIG. 4, which enlarges a part of FIG. 1. The flexible double-sided connector 22 mainly consists of a flexible insulating substrate 24, for example, a polyimide film such as Kapton (trade name) of E.I.Dupont Co. or similar film.

The first connector conductor 26, which is a grounding conductor, and the second connector conductor, 28, which is a signal conductor, are located on the opposite side of the flexible insulator board 24, and a suitable wire form which will be discussed in detail later in this specification is this flexible double-sided connector. It exists on one side or both sides.

Before securing the flexible double-sided connector 22 to the piezoceramic 12 coated with a conductive coating, the ends of the flexible double-sided connector 22 are formed of the first conductor 26, the flexible insulating substrate 24, and the second. The ends of each layer should be visible on one side of the flexible double-sided connector 22 in order of conductor 28.

As shown in FIG. 4, the second connector conductor 28 extends under the first connector conductor 26 and the insulating substrate 24 to form an exposed second contact 28E.

In a similar manner as above, the flexible insulator substrate 24 extends under the first connector conductor 26 along the second connector conductor 28 to form an exposed insulator 24I. Naturally, the first connector conductor 26 remains exposed, forming the first contact 26E exposed.

The flexible double-sided connector 22 is connected to the first and second electrodes 18, 20 of the piezoceramic so that they can be electrically conducted by any suitable conductive adhesive material. This is done by aligning the exposed insulation 24I with one of the insulation ends 16.

The exposed first contact 26E is bonded to the first electrode 18 of the piezoceramic 12 together with the first conductive contact 40. At the same time, the exposed second contact 28E is bonded to the second electrode 20 of the piezoceramic 12 together with the second conductive contact 41.

As discussed in the present invention, the first and second conductive contacts 40 and 41 may be performed by soldering using solder. However, anisotropic conductive adhesives can also be used to form the first and second conductive contacts 40, 41. As already mentioned, the first conductive contact 40 is preferably configured to include a fill 42 for the purpose of contact strengthening.

However, this filling portion 42 extends over most of the sides of the piezoceramic 12 coated with at least a conductive material in the brazing structure. This filling (filling) enhances the adhesion of the contacts between the flexible double-sided connector 22 and the conductive coating 14.

The flexible double-sided connector 22 is generally fastened to a piezoelectric ceramic 12 coated with a conductor before the rest of the transducer is assembled. The piezoceramic 12 is attached to the sound absorbing layer 30 by a suitable adhesive 31, and the rest of the transducer is formed in a manner generally conceived in the art. Of course, the configuration of the array type ultrasonic transducer requires a plurality of ultrasonic transducer elements 10a to 10k, as shown in FIG.

In general, these ultrasonic transducer elements are made by attaching a sound absorbing backing to the piezoelectric ceramics 12 and dicing the piezoelectric ceramics 12. Each electrode formed in the first or second connector conductor portion is aligned to be connected to a particular ultrasonic transducer element 10a-10k. Dicing is generally performed after the flexible double-sided connector 22 is bonded. As a result, the ends of the flexible double-sided connector 22 are also diced together.

The use of the flexible double-sided connector 22 allows considerable flexibility for each of the contacts connected in the arrayed ultrasound transducer 10. FIG. 5 illustrates a first example of a junction, each connected to ultrasonic transducer elements 10a-10d through the use of a flexible double-sided connector 22. 6 and 7 as well as FIG. 5 show the bottom of the piezoelectric ceramics 12 coated with a conductor, where the flexible double-sided connector 22 and the respective conductors are connected.

In the example of FIG. 5, the first connector conductor 26 is commonly connected to all of the ultrasound transducer elements 10a-10d as the first common or ground conductor 26C. However, this common or ground conductor 26C is in turn connected to the electrodes 18a-18d of the first transducer element. As a result, the electrodes 18a to 18d of this first transducer element are commonly connected.

The second connector conductor 28 uses the second connector conductors 28a to 28d to connect to the electrodes 20a to 20d of the second converter element. It is important that the insulating end 16 is connected like a bridge by the exposed insulating portion 24I of the flexible insulating substrate 24. In this way the electrodes 20a to 20d of each second transducer element are approached individually. At the same time, the electrodes 18a to 18d of the first converter element are commonly connected.

Of course, this arrangement may be reversed in the present invention, and the electrodes 28a to 28d of each first transducer element may be used to approach the electrodes 18a to 18d of the first transducer element. At the same time a common ground conductor may be used to collectively connect the electrodes 20a to 20d of the second converter element.

5 shows that the flexible double-sided connector 22 will approach the ultrasound transducer from its edge so that the joint reinforcing fill 42 can be formed. However, this also makes it possible for the flexible double-sided connector 22 to approach the insulation end 16 from another direction (center of the transducer array).

6 shows each of the first and second connector conductors 26a to 26d (28a to 28d), respectively, in contact with the electrodes 18a to 18d (20a to 20d) of the respective first and second ultrasonic elements. It's another way to embody it. Moreover, no common electrode in FIG. 6 was used for any beneficial reason. In other respects, FIG. 6 is essentially identical or identical to FIG. 5.

7 is a view illustrating another example of a transducer connector in the present invention. In FIG. 7, the first and second flexible double-sided connectors 22a and 22b are connected to the respective ultrasonic transducer elements 20a to 20e. As the size of the ultrasonic transducer elements decreases, various problems arise in the size of the connector conductors 26a-26k (28a-28k) due to registration problems as well as shrinkage of the conductor lithography. These problems are greatly reduced by connecting all other ultrasonic transducer elements using a single flexible double-sided connector 22a or 22b.

In FIG. 7 the first connector conductor 26 of the first double-sided connector 22a is only connected to the odd first connector conductors 26a, 26c and 26e, and the second connector conductor of the first double-sided connector 22a. 28 is only connected to the even first connector conductors 26b and 26d.

In a similar manner, the first connector conductor 26 of the second double-sided connector 22b is connected to only the even first respective connector conductors 26b and 26d, and the second connector conductor of the second double-sided connector 22b ( 28 is only connected to the odd first connector conductors 26a, 26c and 26e, respectively.

In FIG. 7 the second connector conductor is connected to a different ultrasonic transducer element than the one connected by the first connector conductor 26. In addition, the first connector conductor 26 of the first flexible double-sided connector 22a is connected to the odd ultrasonic transducer elements 10a, 10c, 10e, and the second connector conductor of FIG. 7 is an even ultrasonic transducer. Connected to elements 10b and 10d. The second connector conductor 28 is in fact the same as the second flexible double-sided connector 22b connected to the odd second connector conductors 28a, 28c and 28e.

Of course, the relationship between the first and second connector conductors 26, 28 is reversed in line with the proposal of the present invention. The first flexible double-sided connector 28a thus has first and second connector conductors 26 and 28, both of which are connected to the odd ultrasonic transducer elements 10a, 10c and 10e. At the same time, the first and second connector conductors 26 and 28 of the corresponding second flexible double-sided connector 28b are connected to even ultrasonic transducer elements 10b and 10d.

One of these solutions provides an inherent advantage in increasing the transducer element density. It is therefore possible to increase the image resolution.

6 illustrates one of the other proposals in the present invention in detail. That is, the first connector conductor 26 and the second connector conductor 28 cause the ultrasonic transducer elements to alternately exhibit opposite polarities. The first transducer element electrodes 18a, 18c, 18e are driven with one polarity while driving the electrodes 18b, 18d of the first transducer element with reverse polarity. This technique results in noise attenuation throughout the transducer.

In the present invention, the thickness of the ground conductors 26 (26a to 26d), which are the first connector conductors, is increased to 50 μm to 50 mm so that the surface temperature of the ultrasonic transducer in operation is lowered to 1 ° C. to 10 ° C. than the conventional one. By helping to maintain the unique characteristics of the ultrasonic transducer, while minimizing the electromagnetic interference (EMI).

The ground conductors 26 (26a to 26d) may be made of at least one of an alloy of gold, copper, silver, aluminum, gold, copper, silver, and aluminum, and the thickness of the ground conductor of the flexible double-sided connector (insulating substrate). For thickening, one of electroless plating or chemical vapor deposition, physical vapor deposition, electroplating, or adhesion of conductor materials can be used.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes may be possible without departing from the technical spirit of the present invention, which is a technology to which the present invention pertains. It is obvious to those of ordinary skill in the field.

As described above, the present invention uses flexible double sided connectors that are easy to bend and have double density, so that the electrodes located on both sides of the piezoelectric ceramic are not only provided with ease of use, but also the element density of the ultrasonic transducer. And the effect is greatly increased.

In addition, the present invention has the effect that when the flexible double-sided connector is bonded to the electrode of the piezoceramic, the strength of the bonding portion is greatly improved by the adhesive material (filling material) to be filled.

In addition, in the present invention, by shifting the first and second patterns of a single flexible double-sided connector, each circuit device can be connected using the first flexible double-sided connector, the second terminal using another second flexible double-sided connector There is an effect that can be connected.

In addition, according to the present invention, through the use of the individual ground of the above structure, each piezoelectric element has an individual ground on the opposite side (the back layer side) of the piezoceramic, so there is an effect that noise is greatly attenuated according to the system used. .

In addition, the concave acoustic lens used in the present invention has an effect of focusing ultrasonic waves effectively and efficiently since the sound wave propagation speed is made of epoxy of a medium faster than in water.

In addition, in the present invention, the shielding layer deposited on the outside of the piezoceramic and the matching layer has an effect of reducing electromagnetic interference (EMI) and achieving electrical shielding with the patient.

In addition, in the present invention, not only the bonding portion of the matching layer, the sound absorbing layer (backing), the piezoelectric ceramic, and the bonding portion of the piezoceramic and the back layer are protected by moisture, but also protected by moisture. There is an effect such as.

In addition, by increasing the thickness of the ground conductor on the flexible double-sided connector, the surface temperature of the ultrasonic transducer is lowered from 1 ° C to 10 ° C, which helps to maintain the unique characteristics of the ultrasonic transducer through such thermal reliability, and at the same time, electromagnetic interference (EMI) Minimize the effects.

Claims (18)

The ultrasonic transducer is contacted with the first electrode layer and the second electrode layer with the first and second electrode layers in electrical contact with the surface of the piezoelectric ceramic, an insulation stage for electrically separating the first and second electrodes, and an insulator film therebetween. The flexible conductors with wires on both sides, the insulator film that extends beyond the first conductor wire at the connecting end of the flexible double-sided connector, and the second conductor wire that extends beyond the insulator film. A stepped structure consisting of a membrane and a second conductor wiring, a first conductor wiring of a flexible double-sided connector connected to the first electrode of the piezoceramic, a second conductor wiring of a flexible double-sided connector connected to the second electrode of the piezoelectric ceramic, Array type consisting of an insulator film covering the insulation ends Acoustic transducer. The method according to claim 1; And the first and second wires of the ultrasonic transducer are all connected to each of the plurality of ultrasonic transducer elements. The method according to claim 1 or 2; And the first wiring of the ultrasonic transducer is individually connected to a plurality of elements, and the second wiring of the ultrasonic transducer is commonly connected to all of the plurality of elements. The method according to claim 1 or 2; The ultrasonic transducer has two insulated ends, and the flexible double-sided circuit board is composed of first and second flexible double-sided circuit boards, and the two first and second flexible double-sided circuit boards each have one of two insulated ends. And all piezoceramic elements connected to one of the flexible double-sided circuit boards. The method according to claim 1 or 2; And the ultrasonic transducer includes both linear and curved transducers. The method according to claim 1 or 2; Ultrasonic transducer, characterized in that the thickness of the ground conductor formed on the flexible double-sided connector to 50㎛ ~ 50mm thick. The method according to claim 6; An array type ultrasonic transducer, characterized in that the ground conductor material is at least one of an alloy of gold, copper, silver, aluminum, gold, copper, silver, and aluminum. The method according to claim 6; An array type ultrasonic transducer using one of electroless plating, chemical vapor deposition, physical vapor deposition, electroplating, and adhesion of conductor materials to increase the thickness of the ground conductor. The piezoelectric ceramic of the ultrasonic transducer is divided into a plurality of elements, and the piezoelectric ceramic is expanded in the main direction (longitudinal direction), the first and second electrode layers contacting both sides of the piezoelectric ceramic, and the energy generated from the piezoelectric ceramic. An array type ultrasonic transducer consisting of a concave acoustic lens having a sound velocity that is faster than the sound velocity of water while being concave in the transverse direction orthogonal to the longitudinal direction so as to focus on a point. The method according to claim 9; The concave acoustic lens is an array type ultrasonic transducer, characterized in that the sound velocity passing through the interior is formed of a material faster than 1700m / s. The method according to claim 9 or 10; And the concave acoustic lens is formed of an epoxy material. The method according to claim 11; And the ultrasonic transducer comprises at least one matching layer, the matching layer being positioned between the ceramic and the concave acoustic lens. The method according to claim 9 or 10; And the ultrasonic transducer is straight or curved. The ultrasonic transducer is the first to enclose a backing, a ceramic layer split into multiple elements extending along the main direction (longitudinal direction), and a ceramic that interacts with each of the multiple elements to convert ultrasonic waves. And an arrayed ultrasonic transducer comprising a second electrode layer, a concave acoustic lens, and a shielding film that extends to the backing and essentially covers all of the above layer structures. The method according to claim 14; The concave acoustic lens surrounds the rest of the above-mentioned layered structure and extends to the above-mentioned backing to provide a mechanical barrier to the rest of the above-mentioned layered structure and a protective film against moisture. Type ultrasonic transducer. The method according to claim 14 or 15; Ultrasonic transducers, characterized in that the linear or curved array ultrasonic transducer. The method according to claim 14 or 15; The concave acoustic lens is an array type ultrasonic transducer, characterized in that the sound velocity passing through the interior is formed of a material faster than 1700m / s. The method according to claim 14 or 15; And the concave acoustic lens is formed of an epoxy material.