Patent Description:
In recent years, an ultrasonic endoscope that observes a state inside a body of a subject by irradiating the inside of the body with ultrasonic waves and receives reflected waves to capture video has been used in medical practice.

In such an ultrasonic endoscope, for example, as disclosed in <CIT>, an ultrasonic oscillator unit is provided in a distal end part of an insertion part that is inserted into a body. In general, the ultrasonic oscillator unit has an ultrasonic oscillator array including a plurality of ultrasonic oscillators (transducers), and the ultrasonic oscillator array is held while being attached to an exterior member provided in the distal end part.

<CIT> discloses a connection structure that electrically connects electrode pads of the ultrasonic oscillators and electrode pads of a flexible printed wiring board (hereinafter, simply referred to as a flexible printed circuit (FPC)) by solder wires or conductive paste (for example, silver paste). Other ends of a plurality of coaxial cables having one ends connected to an ultrasound processor device are electrically connected to the above-described FPC. <CIT> relates to an ultrasonic oscillator unit.

Note that, in the connection structure using soldering out of the above-described connection structures, in a case where heat of soldering in providing the solder wires is transmitted to the ultrasonic oscillators, microcracks may occur in the ultrasonic oscillators due to heat. The microcracks cause degradation of quality of an ultrasound image, and it is not preferred. On the other hand, the connection structure using conductive paste can solve a heat problem by soldering, but has the following problem.

That is, the ultrasonic endoscope is put into, for example, a sterilizing tank of a gas sterilization device and is cleaned after being used in an operation. In this case, the ultrasonic endoscope is cleaned through exposure to sterilizing gas, such as ethylene oxide gas or hydrogen peroxide plasma gas, under a reduced pressure atmosphere; however, sterilizing gas has a component that causes change in quality or deterioration of a member with which sterilizing gas is brought into contact. For this reason, in a case where the ultrasonic oscillator unit is cleaned by sterilizing gas many times, an electrical bonded portion formed of, for example, conductive paste may be deteriorated and disconnection may occur.

The present invention has been accomplished in view of such a situation, and an object of the present invention is to provide an ultrasonic oscillator unit and an ultrasonic endoscope capable of suppressing deterioration of an electrical bonded portion due to sterilizing gas.

To achieve the object of the present invention, there is provided an ultrasonic oscillator unit of the present invention according to claim <NUM> that is disposed in a distal end part of an endoscope insertion part and has a plurality of ultrasonic oscillators, in which the ultrasonic oscillators each have a piezoelectric body, a cable that is electrically bonded to the piezoelectric body is inserted into an internal space of the distal end part, at least one of a plurality of electrical bonded portions from the cable to the piezoelectric body is bonded by a resin material having conductivity (conductive resin material), the electrical bonded portion using the resin material is covered with a first resin layer, and first resin is gas barrier epoxy resin.

In an aspect of the present invention, it is preferable that the epoxy resin has a polyoxyalkylene structure.

In an embodiment of the present invention, it is preferable that the epoxy resin contains an alcohol compound.

In an embodiment of the present invention, it is preferable that a hydroxyl group equivalent of the alcohol compound is equal to or greater than <NUM> and equal to or less than <NUM>, and a molecular weight of the alcohol compound is equal to or greater than <NUM> and equal to or less than <NUM>.

In an embodiment of the present invention, it is preferable that the epoxy resin has a polyamide structure.

In an embodiment of the present invention, it is preferable that the internal space of the distal end part into which the cable is inserted is filled with a second resin layer, and second resin is epoxy resin.

In an embodiment of the present invention, it is preferable that the first resin layer has higher viscosity before curing than the second resin layer.

To achieve the object of the present invention, there is provided an ultrasonic endoscope of the present invention according to claim <NUM> having an insertion part that is inserted into a body, an
ultrasonic observation part that is provided at a distal end of the insertion part, and the ultrasonic oscillator unit of the present invention provided in the ultrasonic observation part.

According to the present invention, it is possible to suppress deterioration of an electrical bonded portion due to sterilizing gas.

Hereinafter, a preferred embodiment of an ultrasonic oscillator unit and an ultrasonic endoscope according to the present invention will be described referring to the accompanying drawings.

<FIG> is a schematic configuration diagram showing an example of an ultrasonography system <NUM> that uses an ultrasonic endoscope <NUM> of the embodiment.

As shown in <FIG>, the ultrasonography system <NUM> comprises the ultrasonic endoscope <NUM>, an ultrasound processor device <NUM> that generates an ultrasound image, an endoscope processor device <NUM> that generates an endoscope image, a light source device <NUM> that supplies illumination light, with which the inside of a body cavity is illuminated, to the ultrasonic endoscope <NUM>, and a monitor <NUM> that displays the ultrasound image and the endoscope image. The ultrasonography system <NUM> comprises a water supply tank 21a that stores cleaning water or the like, and a suction pump 21b that sucks aspirates inside the body cavity.

The ultrasonic endoscope <NUM> has an insertion part <NUM> that is inserted into a body cavity of a subject, an operating part <NUM> that is consecutively provided in a proximal end part of the insertion part <NUM> and is used by an operator to perform an operation, a universal cord <NUM> that has one end connected to the operating part <NUM>, and a distal end part <NUM> of the insertion part <NUM> comprises an ultrasonic observation part <NUM> and an endoscope observation part <NUM> described below.

In the operating part <NUM>, an air and water supply button 28a that opens and closes an air and water supply pipe line (not shown) from the water supply tank 21a, and a suction button 28b that opens and closes a suction pipe line (not shown) from the suction pump 21b are provided sequentially. In the operating part <NUM>, a pair of angle knobs <NUM> and <NUM> and a treatment tool insertion port <NUM> are provided.

In the other end portion of the universal cord <NUM>, an ultrasound connector 32a that is connected to the ultrasound processor device <NUM>, an endoscope connector 32b that is connected to the endoscope processor device <NUM>, and a light source connector 32c that is connected to the light source device <NUM> are provided. The ultrasonic endoscope <NUM> is attachably and detachably connected to the ultrasound processor device <NUM>, the endoscope processor device <NUM>, and the light source device <NUM> respectively through the connectors 32a, 32b, and 32c. The connector 32c comprises an air and water supply tube 34a that is connected to the water supply tank 21a, and a suction tube 34b that is connected to the suction pump 21b.

The insertion part <NUM> has, in order from a distal end side, the distal end part <NUM> that has the ultrasonic observation part <NUM> and the endoscope observation part <NUM>, a bendable part <NUM> that is consecutively provided on a proximal end side of the distal end part <NUM>, and a soft part <NUM> that couples a proximal end side of the bendable part <NUM> and the distal end side of the operating part <NUM>.

The bendable part <NUM> is remotely bent and operated by rotationally moving and operating a pair of angle knobs <NUM> and <NUM> provided in the operating part <NUM>. With this, the distal end part <NUM> can be directed in a desired direction.

The ultrasound processor device <NUM> generates and supplies an ultrasound signal for making an ultrasonic oscillator array <NUM> of an ultrasonic oscillator unit <NUM> (see <FIG>) of the ultrasonic observation part <NUM> described below generate an ultrasonic wave. The ultrasound processor device <NUM> receives and acquires an echo signal reflected from an observation target part irradiated with the ultrasonic wave, by the ultrasonic oscillator array <NUM> and executes various kinds of signal processing on the acquired echo signal to generate an ultrasound image that is displayed on the monitor <NUM>.

The endoscope processor device <NUM> receives and acquires a captured image signal acquired from the observation target part illuminated with illumination light from the light source device <NUM> in the endoscope observation part <NUM> and execute various kinds of signal processing and image processing on the acquired image signal to generate an endoscope image that is displayed on the monitor <NUM>.

To image an observation target part inside a body cavity using the endoscope observation part <NUM> to acquire an image signal, the light source device <NUM> generates illumination light, such as white light including light of three primary colors of red light, green light, and blue light or light of a specific wavelength. Light propagates through a light guide (not shown) and the like in the ultrasonic endoscope <NUM>, and is emitted from the endoscope observation part <NUM>, and the observation target part inside the body cavity is illuminated with light.

The monitor <NUM> receives video signals generated by the ultrasound processor device <NUM> and the endoscope processor device <NUM> and displays an ultrasound image and an endoscope image. In regard to the display of the ultrasound image and the endoscope image, only one image may be appropriately switched and displayed on the monitor <NUM> or both images may be displayed simultaneously.

Next, the configuration of the distal end part <NUM> will be described referring to <FIG>.

<FIG> is a partial enlarged plan view showing the distal end part <NUM> shown in <FIG> and the vicinity thereof the distal end part <NUM>. <FIG> is a sectional view taken along the line III-III shown in <FIG>, and is a longitudinal sectional view of the distal end part <NUM> taken along a center line thereof in a longitudinal direction. <FIG> is a sectional view taken along the line IV-IV shown in <FIG>, and is a cross-sectional view of the ultrasonic oscillator array <NUM> of the ultrasonic observation part <NUM> of the distal end part <NUM> taken along a center line of an arc structure.

As shown in <FIG> and <FIG>, in the distal end part <NUM>, the ultrasonic observation part <NUM> that acquires the ultrasound image is mounted on the distal end side, the endoscope observation part <NUM> that acquires the endoscope image is mounted on the proximal end side, and a treatment tool outlet port <NUM> is provided between the ultrasonic observation part <NUM> and the endoscope observation part <NUM>.

The endoscope observation part <NUM> is configured with an observation window <NUM>, an objective lens <NUM>, a solid-state imaging element <NUM>, illumination windows <NUM>, a cleaning nozzle <NUM>, a wiring cable <NUM> including a plurality of coaxial cables (not shown), and the like.

The treatment tool outlet port <NUM> is connected to a treatment tool channel <NUM> that is inserted into the insertion part <NUM>, and a treatment tool (not shown) that is inserted from the treatment tool insertion port <NUM> of <FIG> is led out from the treatment tool outlet port <NUM> into the body cavity through the treatment tool channel <NUM>.

As shown in <FIG>, the ultrasonic observation part <NUM> comprises the ultrasonic oscillator unit <NUM>, an exterior member <NUM> that holds the ultrasonic oscillator unit <NUM>, and a plurality of coaxial cables <NUM> that are wired in the ultrasonic oscillator unit <NUM>. The exterior member <NUM> is made of a rigid member, such as rigid resin, and configures a part of the distal end part <NUM>.

The ultrasonic oscillator unit <NUM> has the ultrasonic oscillator array <NUM> that includes a plurality of ultrasonic oscillators <NUM>, an electrode <NUM> that is provided on an end portion side of the ultrasonic oscillator array <NUM> in a width direction (a direction perpendicular to the longitudinal axis direction of the insertion part <NUM>), a backing material layer <NUM> that supports each ultrasonic oscillator <NUM> from a lower surface side, an FPC <NUM> that is disposed along a side surface of the backing material layer <NUM> in the width direction and is connected to the electrode <NUM>, and a filler layer <NUM> as a second resin layer with which an internal space <NUM> between the exterior member <NUM> and the backing material layer <NUM> is filled.

The ultrasonic oscillator unit <NUM> has an acoustic matching layer <NUM> laminated on the ultrasonic oscillator array <NUM>, and an acoustic lens <NUM> laminated on the acoustic matching layer <NUM>. That is, the ultrasonic oscillator unit <NUM> is configured as a laminate <NUM> having the acoustic lens <NUM>, the acoustic matching layer <NUM>, the ultrasonic oscillator array <NUM>, and the backing material layer <NUM>.

The ultrasonic oscillator array <NUM> is configured with a plurality of rectangular parallelepiped ultrasonic oscillators <NUM> arranged in a convex arc shape outward. The ultrasonic oscillator array <NUM> is an array of <NUM> to <NUM> channels consisting of <NUM> to <NUM> ultrasonic oscillators <NUM>, for example. Each of the ultrasonic oscillators <NUM> has a piezoelectric body <NUM>.

The ultrasonic oscillator array <NUM> of the present example is configured by arranging a plurality of ultrasonic oscillators <NUM> at predetermined pitches in a one-dimensional array shape as an example. The ultrasonic oscillators <NUM> that configure the ultrasonic oscillator array <NUM> are arranged at regular intervals in a convex bent shape along an axial direction of the distal end part <NUM> (the longitudinal axis direction of the insertion part <NUM>) and are sequentially driven based on drive signals input from the ultrasound processor device <NUM> (see <FIG>). With this, convex electronic scanning is performed with a range where the ultrasonic oscillators <NUM> shown in <FIG> are arranged, as a scanning range.

The electrode <NUM> of the ultrasonic oscillator array <NUM> has an individual electrode 52a individually and independently provided for each ultrasonic oscillator <NUM>, and an oscillator ground 52b that is a common electrode common to all the ultrasonic oscillators <NUM>. In <FIG>, a plurality of individual electrodes 52a are disposed on lower surfaces of end portions of a plurality of ultrasonic oscillators <NUM>, and the oscillator ground 52b is provided on upper surfaces of the end portions of the ultrasonic oscillators <NUM>.

The acoustic matching layer <NUM> is a layer that is provided for taking acoustic impedance matching between the subject and the ultrasonic oscillators <NUM>.

The acoustic lens <NUM> is a lens that is provided for converging the ultrasonic waves emitted from the ultrasonic oscillator array <NUM> toward the observation target part. In the acoustic lens <NUM>, powder, such as titanium oxide, alumina, or silica, is mixed as necessary to take acoustic impedance matching between the subject and the ultrasonic oscillators <NUM> in the acoustic matching layer <NUM>, and to increase the transmittance of the ultrasonic waves. The acoustic lens <NUM> is formed of, for example, silicon-based resin (millable type silicon rubber, liquid silicon rubber, or the lie), butadiene-based resin, or polyurethane-based resin.

As shown in <FIG> and <FIG>, the backing material layer <NUM> is a layer of a member made of a backing material disposed on an inside with respect to the arrangement surface of a plurality of ultrasonic oscillators <NUM>, that is, a rear surface (lower surface) of the ultrasonic oscillator array <NUM>. The backing material layer <NUM> has a role of mechanically and flexibly supporting the ultrasonic oscillator array <NUM> and attenuating ultrasonic waves propagated to the backing material layer <NUM> side among ultrasound signals oscillated from a plurality of ultrasonic oscillators <NUM> or reflected and propagated from the observation target. For this reason, the backing material is made of a material having rigidity, such as hard rubber, and an ultrasonic wave attenuation material (ferrite, ceramics, or the like) is added as needed.

The filler layer <NUM> is a layer with which the internal space <NUM> between the exterior member <NUM> and the backing material layer <NUM> is filled, and has a role of fixing the FPC <NUM>, the coaxial cables <NUM>, and various wiring portions. It is preferable that the acoustic impedance of the filler layer <NUM> matches the acoustic impedance of the backing material layer <NUM> with given accuracy or higher such that the ultrasound signals propagated from the ultrasonic oscillator array <NUM> to the backing material layer <NUM> side are not reflected at a boundary surface between the filler layer <NUM> and the backing material layer <NUM>. It is preferable that the filler layer <NUM> is made of a member having heat dissipation to increase efficiency in dissipating heat generated in a plurality of ultrasonic oscillators <NUM>. In a case where the filler layer <NUM> has heat dissipation, since heat is received from the backing material layer <NUM>, the FPC <NUM>, the coaxial cables <NUM>, and the like, heat dissipation efficiency can be improved.

With the ultrasonic oscillator unit <NUM> configured as described above, in a case where each ultrasonic oscillator <NUM> of the ultrasonic oscillator array <NUM> is driven, and a voltage is applied to the electrode <NUM> of the ultrasonic oscillator <NUM>, the piezoelectric body <NUM> oscillates to sequentially generate ultrasonic waves, and the irradiation of the ultrasonic waves is performed toward the observation target part of the subject. Then, as a plurality of ultrasonic oscillators <NUM> are sequentially driven by an electronic switch, such as a multiplexer, scanning with ultrasonic waves is performed in a scanning range along a curved surface on which the ultrasonic oscillator array <NUM> is disposed, for example, a range of about several tens mm from the center of curvature of the curved surface.

In a case where the echo signal reflected from the observation target part is received, the piezoelectric body <NUM> vibrates to generate a voltage and outputs the voltage as an electric signal corresponding to the received ultrasound echo to the ultrasound processor device <NUM>. Then, the electric signal is subjected to various kinds of signal processing in the ultrasound processor device <NUM> and is displayed as an ultrasound image on the monitor <NUM>.

By the way, the FPC <NUM> shown in <FIG> has a plurality of electrode pads <NUM> that are electrically connected to a plurality of individual electrode 52a at one end, and a plurality of electrode pads <NUM> that are electrically connected to a plurality of signal lines 56a of the coaxial cable <NUM> at the other end. The FPC <NUM> also has a ground portion (not shown) that is electrically connected to the oscillator ground 52b.

Here, as shown in <FIG>, the coaxial cables <NUM> of the present example are bundled using an outer coat <NUM> on the proximal end side of the distal end part <NUM>, and are led out from the outer coat <NUM> and are connected to the FPC <NUM> at the time of wiring. As shown in a sectional view of <FIG>, each coaxial cable <NUM> comprises a signal line 56a connected to the electrode pad <NUM> on a center side, and has an insulating outer coat 56b provided in a layer outside the signal line 56a, a shield layer 56c provided in a layer outside the outer coat 56b, and an insulating outer coat 56d provided in an outermost layer.

Returning to <FIG>, an electrical bonded portion <NUM> of the electrode pad <NUM> and the individual electrode 52a is bonded by a conductive resin material <NUM>, and an electrical bonded portion <NUM> of the electrode pad <NUM> and the signal line 56a is also boned by the conductive resin material <NUM>.

Examples of the above-described resin material <NUM> include an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) obtained by mixing thermosetting resin with fine conductive particles and forming the mixture into a film. The electrical bonded portions <NUM> and <NUM> bonded by such a resin material <NUM> may be deteriorated and disconnected due to contact with sterilizing gas, such as ethylene oxide gas or hydrogen peroxide plasma gas, in a case where the ultrasonic endoscope <NUM> is cleaned by a gas sterilization device.

Accordingly, in the ultrasonic endoscope <NUM> of the embodiment, as shown in <FIG>, each of the electrical bonded portions <NUM> and <NUM> is coated with a low reactive epoxy resin layer <NUM> that is a first resin layer. Then, even though the above-described sterilizing gas is transmitted through the acoustic lens <NUM> or the filler layer <NUM> and enters the electrical bonded portions <NUM> and <NUM> side, since the above-described epoxy resin layer <NUM> exhibits a function as a gas barrier, it is possible to suppress contact of the sterilizing gas with the electrical bonded portions <NUM> and <NUM>. With this, it is possible to suppress deterioration of the electrical bonded portions <NUM> and <NUM> due to the sterilizing gas.

Accordingly, with the ultrasonic endoscope <NUM> of the embodiment, since the electrical bonded portions <NUM> and <NUM> from the coaxial cable <NUM> to the piezoelectric body <NUM> are bonded by the conductive resin material <NUM>, and the electrical bonded portions <NUM> and <NUM> using the resin material <NUM> are coated with the gas barrier epoxy resin layer <NUM>, it is possible to suppress deterioration of the electrical bonded portions <NUM> and <NUM> due to the sterilizing gas.

Although it is preferable that all electrical bonded portions from the coaxial cable <NUM> to the piezoelectric body <NUM> are coated with the epoxy resin layer <NUM>, the present invention is not limited thereto, at least the electrical bonded portions <NUM> and <NUM> that are bonded by the conductive resin material <NUM> may be coated with the epoxy resin layer <NUM>.

In the ultrasonic endoscope <NUM> of the embodiment, although an aspect where the present example is applied to the connection structure in which the piezoelectric bodies <NUM> and the coaxial cables <NUM> are connected through the FPC <NUM> has been described, a connection structure to which the present example is applied is not limited thereto. For example, the present example can be applied to a first another connection structure in which the piezoelectric bodies <NUM> and the coaxial cables <NUM> are connected through electrical bonded portions, and a second another connection structure in which a first FPC connected to the piezoelectric bodies <NUM> and a second FPC connected to the coaxial cables <NUM> are connected through electrical bonded portions. In this case, in the second another connection structure, since stress is likely to be concentrated on the above-described electrical bonded portions at the time of handling during manufacturing, it is preferable that the electrical bonded portions are coated with the epoxy resin layer <NUM> in advance. With this, since mechanical strength of the electrical bonded portions is improved, it is possible to restrain the electrical bonded portions from being damaged at the time of handling during manufacturing.

In the ultrasonic endoscope <NUM> of the embodiment, although the resin material <NUM> is the ACF, the present invention is not limited thereto. For example, a resin material in which a conductive filler, such as metallic particles, is dispersed into binder resin, such as epoxy or urethane, and the conductive filler forms a conductive path after adhesion may be used. Examples of this resin material include a conductive paste, such as a silver paste.

Hereinafter, a specific example of the epoxy resin layer <NUM> will be described.

It is preferable that the epoxy resin of the epoxy resin layer <NUM> has a polyoxyalkylene structure. With this, gas resistance of the epoxy resin layer <NUM> to the sterilizing gas is improved.

It is preferable that the epoxy resin of the epoxy resin layer <NUM> contains an alcohol compound. With this, gas resistance of the epoxy resin layer <NUM> to the sterilizing gas is improved. In this case, it is more preferable that a hydroxyl group equivalent of the alcohol compound is equal to or greater than <NUM> and equal to or less than <NUM>, and a molecular weight of the alcohol compound is equal to or greater than <NUM> and equal to or less than <NUM>. With this, it is possible to obtain the same gas resistance as the above-described polyoxyalkylene structure.

It is preferable that the epoxy resin of the epoxy resin layer <NUM> has a polyamide structure. With this, gas resistance of the epoxy resin layer <NUM> to the sterilizing gas is improved.

On the other hand, it is preferable that second resin for forming the filler layer <NUM> is epoxy resin, and it is more preferable that the epoxy resin has a polyamide structure. With this, it is possible to allow the filler layer <NUM> to have gas resistance.

Here, epoxy resin having high gas resistance (that is, low responsiveness to gas) has a large molecular weight and high viscosity. From such situations, it is preferable that epoxy resin having high viscosity before curing to some extent is employed as the first resin layer with which the electrical bonded portions <NUM> and <NUM> are coated. With this, it is possible to increase gas resistance, and to reliably coat the electrical bonded portions <NUM> and <NUM>.

It is preferable that epoxy resin having lower viscosity before curing than the first resin is employed as the second resin for forming the filler layer <NUM>. With this, since it is possible to spread the second resin over the entire region of the internal space <NUM>, it is possible to suppress the occurrence of air bubbles that cause gas transmission, in the filler layer <NUM>.

It is preferable that the viscosity before curing of the first resin layer is equal to or greater than <NUM> Pa·s and equal to or less than <NUM> Pa·s as an example. The viscosity before curing of the second resin layer is preferably equal to or greater than <NUM> Pa·s and equal to or less than <NUM> Pa·s, and is more preferably equal to or greater than <NUM> Pa·s and equal to or less than <NUM> Pa·s.

By the way, since the ultrasonic endoscope is inserted into a human body, there is a need for a reduction in diameter of the insertion part. To realize the reduction in diameter of the insertion part, the cable that is connected to the ultrasonic oscillator is very fine compared to a cable that is used in a body surface echo. As a result, there is a problem in that mechanical strength of the electrical bonded portions is very weak, and the electrical bonded portions are easily damaged at the time of handling during manufacturing. In particular, since a load is applied to the cable at the time of work of storing the ultrasonic oscillator in the distal end part, there is a high possibility that the electrical bonded portions are damaged.

In a case where solder, instead of a conductive resin material, is used in bonding for a small ultrasonic oscillator that is employed in the ultrasonic endoscope, and in a case where heat equal to or higher than <NUM> degrees is transmitted to the piezoelectric body, the piezoelectric body has an increased risk of being damaged due to the occurrence of microcracks in the piezoelectric body. Alternatively, a disposition interval of the electrode pads of the FPC is narrow and bonding work is impossible with solder, and a solder defect is likely to occur. For this reason, a place where bonding needs to be performed using a conductive resin material necessarily occurs. In this case, since the conductive resin material has weak mechanical strength compared to solder, there is a higher possibility that the electrical bonded portions are damaged at the time of handling during manufacturing. In this way, an ultrasonic endoscope of the related art has a problem that the electrical bonded portions are easily damaged at the time of handling during manufacturing.

In contrast, in the ultrasonic endoscope <NUM> of the embodiment, since the electrical bonded portions <NUM> and <NUM> are coated with the epoxy resin layer <NUM>, mechanical strength of the electrical bonded portions <NUM> and <NUM> is improved. With this, the ultrasonic endoscope <NUM> of the embodiment solves the problem that the electrical bonded portions <NUM> and <NUM> are easily damaged at the time of handling during manufacturing.

Claim 1:
An ultrasonic oscillator unit (<NUM>) that is disposed in a distal end part (<NUM>) of an endoscope insertion part (<NUM>) and has a plurality of ultrasonic oscillators (<NUM>),
wherein the ultrasonic oscillators each have a piezoelectric body (<NUM>),
a cable (<NUM>) that is electrically bonded to the piezoelectric body (<NUM>) is inserted into an internal space (<NUM>) of the distal end part (<NUM>),
at least one of a plurality of electrical bonded portions (<NUM>,<NUM>) from the cable (<NUM>) to the piezoelectric body (<NUM>) is bonded by a resin material (<NUM>) having conductivity,
the at least one of the plurality of electrical bonded portions using the resin material (<NUM>) is covered with a first resin layer (<NUM>) whose material is different from that of the resin material (<NUM>), and
the first resin layer is made of gas barrier epoxy resin (<NUM>).