JP6791671B2 - Ultrasonic probe - Google Patents

Description

Embodiments of the present invention relate to ultrasonic probes.

As a medical image diagnostic device, an ultrasonic diagnostic device that scans the inside of a subject with ultrasonic waves and images the internal state of the subject based on the received signal generated from the reflected waves from the inside of the subject. It has been known. The ultrasonic diagnostic apparatus transmits ultrasonic waves into the body of the subject from the ultrasonic probe, receives the reflected wave generated by the mismatch of acoustic impedance in the body of the subject by the ultrasonic probe, and generates a received signal.

Further, the ultrasonic probe is provided with a piezoelectric vibrator, and a plurality of the piezoelectric vibrators are arranged on an array in the scanning direction. The piezoelectric vibrator vibrates based on the transmitted signal to generate ultrasonic waves, and also receives reflected waves to generate a received signal.

Here, an ultrasonic probe having an element arrangement in both a first element arrangement direction (azimus direction) and a second element arrangement direction (elevation direction) orthogonal to the first element direction has been developed. For example, an ultrasonic probe having a piezoelectric element of a 1.5D array is known, and the ultrasonic probe having this element arrangement can electronically scan an element in the azimuth direction and an element in the elevation direction. Can also be scanned electronically, so that a more ideal ultrasonic transmission / reception sound field can be formed.

Common ultrasonic probes include, for example, a piezoelectric body, an electrode layer for applying a voltage to the surface of the piezoelectric body, a flexible printed circuit board for drawing out the electrode layer from the acoustic radiation direction of the piezoelectric body, and acoustics. It is composed of matching layers.

However, for example, in the case of an ultrasonic probe including a piezoelectric element of a 1.5D array, the strength of the element decreases due to the fine element size of the piezoelectric element, and there is a concern that manufacturing defects and reliability may decrease.

Japanese Unexamined Patent Publication No. 2010-278766

An object to be solved by the present invention is to provide an ultrasonic probe having a two-dimensional element arrangement, which has high element strength, high quality, and high reliability.

The ultrasonic probe of the embodiment is an ultrasonic probe in which a plurality of elements are arranged in both the azimuth direction and the elevation direction, and is laminated with a piezoelectric body having a piezoelectric effect in the acoustic irradiation direction of the piezoelectric body. Both the piezoelectric body and the matching layer are divided into a plurality of parts in the azimuth direction, and the matching layer is not divided in the elevation direction, and the piezoelectric layer is not divided. The body is divided into a plurality of elements to form the plurality of elements.

The schematic block diagram which showed an example of the schematic structure of the ultrasonic probe of 1st Embodiment. Explanatory drawing when the ultrasonic probe of 1st Embodiment was seen in the azimuth direction. Explanatory drawing when the III-III'cross section of the ultrasonic probe of 1st Embodiment was seen in the elevation direction. Explanatory drawing when the conventional ultrasonic probe is seen in the azimuth direction. Explanatory drawing when the VV'cross section of the conventional ultrasonic probe is seen in the elevation direction. Explanatory drawing which showed the flexible printed circuit board used in the ultrasonic probe of 1st Embodiment. Explanatory drawing when the ultrasonic probe of the 2nd Embodiment was seen in the azimuth direction. Explanatory drawing when the VIII-VIII'cross section of the ultrasonic probe of the 2nd Embodiment is seen in the elevation direction.

Hereinafter, the ultrasonic probe of the embodiment will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 is a schematic configuration diagram showing an example of a schematic configuration of the ultrasonic probe 10 of the first embodiment.

As shown in FIG. 1, the ultrasonic probe 10 of the first embodiment includes a flexible printed circuit board FPC, a plurality of piezoelectric PIs, a turning electrode EP, a first matching layer ML1, a second matching layer ML2, and an acoustic lens SL. It is configured to prepare.

The flexible printed circuit board FPC extracts signals from each of the plurality of piezoelectric PIs and forms a common ground on the surface of the piezoelectric PIs. The common ground is formed together with the turning electrode EP described later.

Each of the plurality of piezoelectric PIs is composed of very elongated oscillators, and a large number of piezoelectric PIs are arranged side by side like a comb tooth to form an oscillator group. The oscillator is, for example, a piezoelectric element, and has a piezoelectric effect capable of mutually converting voltage and sound. In FIG. 1, the 1.5D array is divided into 14 pieces in the azimuth direction with three piezoelectric material PIs in the elevation direction, but this is just for showing the structure in an easy-to-understand manner. It is not limited to. In practice, a large number of, for example, 128 to 256 piezoelectric PIs are arranged in the azimuth direction.

In the present embodiment, in the ultrasonic probe 10, the direction in which a plurality of piezoelectric PIs are arranged to the right with respect to the paper surface is referred to as the azimuth direction, and the direction orthogonal to the azimuth direction is three piezoelectrics. The longitudinal direction in which the body PIs are arranged is called the elevation direction. Further, the direction in which the acoustic lens SL is provided from the plurality of piezoelectric PIs is referred to as the acoustic radiation direction.

The turning electrode EP is a ground electrode common to the acoustic irradiation direction surfaces of each of the plurality of piezoelectric PIs, and the ground electrode is formed up to the end of the surface opposite to the acoustic irradiation direction of the piezoelectric PIs. In other words, a ground electrode is formed so as to surround the piezoelectric PI from the acoustic radiation direction of the first matching layer ML1 and the second matching layer ML2 in the elevation direction of each of the piezoelectric PIs. This shape will be described separately.

The first matching layer ML1 and the second matching layer ML2 are acoustic matching layers, and are adapted to match the vibrators, which are a plurality of piezoelectric PIs, with the living body.

The acoustic lens SL is made of a material whose sound velocity is slower than the sound velocity of a living body in order to narrow the ultrasonic beam in the acoustic radiation direction, and is attached to the front surface of the vibrator which is each piezoelectric PI. The acoustic lens SL forms a thin beam as a whole by narrowing the ultrasonic beam.

Further, the ultrasonic probe 10 of the present embodiment is intended for an ultrasonic probe having a two-dimensional element arrangement in which a plurality of elements are arranged in both the azimuth direction and the elevation direction. In the first embodiment, as an example, the ultrasonic probe 10 in which the piezoelectric elements are arranged by a 1.5D array is shown, but the present invention is not limited to this. For example, it may be an ultrasonic probe in which piezoelectric elements are arranged by a 2D array.

Hereinafter, the ultrasonic probe 10 of the first embodiment will be described in more detail.

FIG. 2 is an explanatory view when the ultrasonic probe 10 of the first embodiment is viewed in the azimuth direction. Further, FIG. 3 is an explanatory view when the cross section III-III'of the ultrasonic probe 10 of the first embodiment is viewed in the elevation direction. In addition, in FIG. 2 and FIG. 3, the acoustic lens SL is omitted.

As shown in FIG. 2, the ultrasonic probe 10 of the first embodiment is configured to include a flexible printed circuit board FPC, a plurality of piezoelectric PIs, a turning electrode EP, a first matching layer ML1 and a second matching layer ML2. ing. Each of the plurality of piezoelectric PIs has a signal electrode PN on the flexible printed circuit board FPC side.

Each of the plurality of piezoelectric PIs corresponds to the magnitude of the voltage between the signal electrode PN and the turning electrode EP, which is the ground electrode, when a voltage is applied from the corresponding signal electrode PN at the time of transmission. Due to the piezoelectric effect, an ultrasonic signal is generated. On the other hand, at the time of reception, the received ultrasonic signal is applied to the piezoelectric body PI, and a voltage corresponding to the magnitude of the received ultrasonic signal is generated between the signal electrode PN and the turning electrode EP which is the ground electrode. Occur.

In the present embodiment, the piezoelectric body is divided into a plurality of parts, and the ultrasonic probe 10 is formed by the plurality of piezoelectric body PIs. As an example, the ultrasonic probe 10 including the piezoelectric element of the 1.5D array will be described, and it is assumed that there are three piezoelectric PIs in the elevation direction.

Further, as shown in FIGS. 2 and 3, the first matching layer ML1 and the second matching layer ML2 are laminated in the acoustic irradiation direction of the plurality of piezoelectric PIs.

In the present embodiment, both the piezoelectric PI and the first matching layer ML1 and the second matching layer ML2 are divided into a plurality of parts in the azimuth direction, and the first matching layer ML1 and the second matching layer ML1 and the second matching layer ML2 are divided in the elevation direction. The matching layer ML2 is not divided, but the piezoelectric PI is divided into a plurality of elements to form a plurality of elements.

By adopting such a configuration, in the first embodiment, even if the element size of each piezoelectric body PI is miniaturized, the first matching layer ML1 and the second matching layer ML2 are divided in the elevation direction. Therefore, the strengthening of the element can be maintained, and the quality of the ultrasonic probe 10 can be maintained in a high state. Moreover, since the quality can be maintained in a high state, the reliability of the ultrasonic probe 10 can be maintained high.

Assuming that the first matching layer ML1 is made of a non-conductive material, a ground electrode GE is provided on the EP side of the rotating electrode of the first matching layer ML1. By connecting the ground electrode GE and the turning electrode EP, the first matching layer ML1 and each of the plurality of piezoelectric PIs can be grounded at a reference potential. For example, when the first matching layer ML1 is made of a conductive material, it is not necessary to provide the ground electrode GE.

Here, in order to clarify the difference from the conventional ultrasonic probe 10A, the conventional configuration will be described.

FIG. 4 is an explanatory view of the conventional ultrasonic probe 10A when viewed in the azimuth direction. FIG. 5 is an explanatory view when the VV'cross section of the conventional ultrasonic probe 10A is viewed in the elevation direction.

As shown in FIG. 4, in the conventional ultrasonic probe 10A, the first matching layer ML1 and the second matching layer ML2 are divided in the elevation direction as compared with the ultrasonic probe 10 shown in FIG. The adjacent first matching layer ML1 and second matching layer ML2 are adhered to each other by the adhesive AT in the elevation direction, but it is assumed that the strength of the element is lowered by being divided.

On the other hand, in the ultrasonic probe 10 of the first embodiment shown in FIG. 2, since the first matching layer ML1 and the second matching layer ML2 are not divided between the elements in the elevation direction, the strength of the elements is increased. It is possible to maintain high quality while maintaining high strength of the element without causing deterioration. Further, since the work of dividing the first matching layer ML1 and the second matching layer ML2 does not occur, a highly reliable ultrasonic probe can be provided even in the work process.

FIG. 5 is an explanatory view when the VV'cross section of the conventional ultrasonic probe 10A is viewed in the elevation direction.

In FIG. 5, when the VV'cross section of the conventional ultrasonic probe 10A is viewed in the elevation direction, the III-III' cross section of the ultrasonic probe 10 of the first embodiment shown in FIG. 3 is viewed in the elevation direction. It shows that it has the same configuration as the explanatory diagram when viewed in.

That is, the ultrasonic probe 10 of the first embodiment shows that the manufacturing process is not so different from that of the conventional ultrasonic probe 10A as compared with the conventional ultrasonic probe 10A. That is, the ultrasonic probe 10 of the first embodiment is different from the conventional manufacturing process of the ultrasonic probe 10A except that there is no step of dividing the first matching layer ML1 and the second matching layer ML2 in the elevation direction. Almost the same manufacturing process can be applied.

Since the element size in the elevation direction is larger than the element size in the azimuth direction, the influence of acoustic crosstalk due to the fact that the first matching layer ML1 and the second matching layer ML2 are not divided is sufficiently ignored. can do.

Next, the flexible printed circuit board FPC and the turning electrode EP will be described.

As shown in FIGS. 2 and 3, the ultrasonic probe 10 is provided with a flexible printed circuit board FPC that extracts signals of each of the divided piezoelectric PIs.

The piezoelectric PI includes a rotating electrode EP that wraps around from an electrode common to each of the divided piezoelectric PIs on the acoustic irradiation direction side to the end of a surface on the side opposite to the acoustic irradiation direction of the piezoelectric PI. , A signal electrode PN connected to each of the divided piezoelectric PIs is formed.

In the rotating electrode EP, the electrodes are formed as a common ground (GND) from the electrode common to the acoustic irradiation direction side of the piezoelectric PI to the end of the surface on the direction opposite to the acoustic irradiation direction of the piezoelectric PI. There is. In other words, the turning electrode EP forms an electrode layer so as to surround the piezoelectric PI in the elevation direction of the piezoelectric PI, and forms a common ground (GND).

In the present embodiment, the turning electrodes EP are arranged in a plurality in the azimuth direction as shown in FIG.

On the other hand, a flexible printed circuit board FPC is provided on the opposite side of each piezoelectric PI in the acoustic irradiation direction.

FIG. 6 is an explanatory view showing a flexible printed circuit board FPC used in the ultrasonic probe 10 of the first embodiment.

FIG. 6A shows the surface of the flexible printed circuit board FPC, that is, the surface in the acoustic irradiation direction. Further, FIG. 6B shows the back surface of the flexible printed circuit board FPC.

In FIGS. 6A and 6B, the holes formed in the flexible printed circuit board FPC indicate through-holes TH. In FIG. 6A, the hatched portion shows the ground pattern of the ground conductor GD to which the end portion of the turning electrode EP surrounding the piezoelectric body PI is connected. Further, in FIG. 6B, the hatched portion indicates the connection portion of the signal, and the signal is extracted from each of the plurality of piezoelectric PIs via the through hole TH, and is formed on the back surface of the flexible printed circuit board FPC. , Indicates that it is wired by a signal line.

That is, the flexible printed circuit board FPC is provided with a through hole TH penetrating from the surface (front surface) on which the piezoelectric PI is provided to the surface (back surface) on the opposite side of the flexible printed circuit board FPC, and is a rotating electrode as a common ground. Both ends of the EP and the ground pattern of the ground conductor GD on the surface of the flexible printed circuit board FPC are connected.

Further, in the flexible printed circuit board FPC, the signal electrode PN of each of the divided piezoelectric PIs is wired on the back surface of the flexible printed circuit board FPC via a through hole TH penetrating the flexible printed circuit board FPC. By adopting such a configuration, the flexible printed circuit board FPC and each piezoelectric PI are collectively bonded.

As a result, the flexible printed substrate FPC forms the ground conductor GD connected to the turning electrode EP and the plurality of signal conductors SD connected to each of the signal electrode PN on the same surface, and is flexible with the piezoelectric PI. While configured to be collectively joined to the printed substrate FPC, the signals of each signal electrode PN are wired on the back surface of the flexible printed substrate FPC via a through hole TH penetrating the flexible printed substrate FPC. Will be done.

Therefore, the ultrasonic probe 10 of the first embodiment is capable of extracting the respective signals of the plurality of piezoelectric PIs through the respective through-holes TH, and is provided with the piezoelectric PIs. The end portion of the turning electrode EP can be formed as an electrode of a common ground on the same surface as the surface of the flexible printed substrate FPC.

As described above, in the ultrasonic probe 10 of the first embodiment, the first matching layer ML1 and the second matching layer ML2 are divided in the elevation direction even if the element size of the piezoelectric body PI is reduced. Therefore, the strengthening of the element can be maintained, and the quality of the ultrasonic probe 10 can be maintained in a high state. Moreover, since the quality can be maintained in a high state, the reliability of the ultrasonic probe 10 can be maintained high.

Further, in the flexible printed substrate FPC of the ultrasonic probe 10 of the first embodiment, the ground conductor GD connected to the turning electrode EP and the plurality of signal conductors SD connected to each of the signal electrode PN are flush with each other. The signal of each signal electrode PN is transmitted to the flexible printed substrate FPC through a through hole penetrating the flexible printed substrate FPC while the piezoelectric PI and the flexible printed substrate FPC are collectively bonded to each other. It is configured to be wired on the back side of.

As a result, the ultrasonic probe 10 can avoid complication of the structure of the flexible printed circuit board FPC, and the degree of freedom of wiring can be improved by wiring the signal line on the back surface of the flexible printed circuit board FPC. Can be done.

In the first embodiment, the configuration in which the piezoelectric PI, the turning electrode EP, and the flexible printed circuit board FPC shown in FIG. 6 are collectively bonded is not disclosed in the prior art, and has an advantageous effect. ing.

Therefore, the ultrasonic probe 10 of the first embodiment may be configured independently by the configuration in which the piezoelectric PI, the turning electrode EP, and the flexible printed circuit board FPC shown in FIG. 6 are collectively bonded. ..

That is, in the ultrasonic probe 10 of the first embodiment, the piezoelectric PI and the piezoelectric PI regardless of whether the first matching layer ML1 and the second matching layer ML2 are divided or not. And, the configuration in which the turning electrode EP and the flexible printed circuit board FPC shown in FIG. 6 are collectively bonded can be applied.

As a result, the ultrasonic probe 10 can avoid complication of the structure of the flexible printed circuit board FPC, and the degree of freedom of wiring can be improved by wiring the signal line on the back surface of the flexible printed circuit board FPC. Can be done.

(Second Embodiment)
In the second embodiment, in addition to the first embodiment, a backing material called a backing is further provided.

FIG. 7 is an explanatory view when the ultrasonic probe 10 of the second embodiment is viewed in the azimuth direction. FIG. 8 is an explanatory view when the VIII-VIII'cross section of the ultrasonic probe 10 of the second embodiment is viewed in the elevation direction.

As shown in FIGS. 7 and 8, in the ultrasonic probe 10 of the second embodiment, the piezoelectric body PI has a surface opposite to the surface on which the first matching layer ML1 and the second matching layer ML2 are laminated. Is provided with a backing material BM.

The back material BM is divided together with a plurality of piezoelectric PIs, a first matching layer ML1 and a second matching layer ML2 in both the azimuth direction and the elevation direction, and forms an element with each of the plurality of piezoelectric PIs. It is designed to do.

The backing material BM is made of, for example, a conductive material, and not only has an acoustic absorption effect, but can also reinforce the arrangement of the piezoelectric PI. The backing material BMs arranged along the elevation direction may be bonded to each other with the adhesive AT.

According to at least one embodiment described above, in an ultrasonic probe having a two-dimensional element arrangement such as a 1.5D array or a 2D array, the element has high strength, high quality, and high reliability. An ultrasonic probe can be provided.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... Ultrasonic probe FPC ... Flexible printed substrate EP ... Rotating electrode PI ... Piezoelectric body ML1 ... First matching layer ML2 ... Second matching layer SL ... Acoustic lens TH ... Through hole PN ... Signal electrode GD ... Ground conductor SD ... Signal Conductor GE ... Ground electrode

Claims (3)

An ultrasonic probe in which a plurality of elements are arranged in both the azimuth direction and the elevation direction.
Piezoelectric material with piezoelectric effect and
The matching layer laminated in the acoustic irradiation direction of the piezoelectric material and
A backing material that has conductivity and sound absorption effect ,
A circuit board that extracts the signal of each of the divided piezoelectric bodies,
With
The front and back materials are provided on the opposite side of the surface on which the matching layer of the piezoelectric body is laminated, and are provided between the piezoelectric body and the circuit board.
The piezoelectric body, the matching layer, and the backing material are divided into a plurality of parts in the azimuth direction, and in the elevation direction, the matching layer is not divided, and the piezoelectric body and the backing material are separated. An ultrasonic probe that is divided into a plurality of elements to form the plurality of elements. The piezoelectric body is a rotating electrode that wraps around from an electrode common to the acoustic irradiation direction side of each of the divided piezoelectric bodies to the end of a surface of the piezoelectric body on the direction opposite to the acoustic irradiation direction. And a signal electrode connected to each of the divided piezoelectric bodies are formed.
The circuit board
A ground conductor connected to the turning electrode and a plurality of signal conductors connected to each of the signal electrodes are formed on the same surface so that the piezoelectric body and the circuit board are collectively joined. The ultrasonic probe according to claim 1, wherein the signals of the signal electrodes are wired on the back surface of the circuit board through a through hole penetrating the circuit board. The plurality of grooves that divide the piezoelectric body and the backing material in the azimuth direction and the elevation direction are filled with an adhesive.
The ultrasonic probe according to claim 1 or 2.

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