JP4071084B2 - Manufacturing method of two-dimensional array ultrasonic probe - Google Patents

Description

[0001]
The present invention relates to a method for manufacturing a two-dimensional array ultrasonic probe.
BACKGROUND OF THE INVENTION
[0002]
[Prior art]
As an ultrasonic probe used in a medical ultrasonic diagnostic apparatus, a piezoelectric vibrator composed of a plate-like piezoelectric body having electrodes on the upper and lower sides is divided into two-dimensional directions to form a plurality of piezoelectric vibrator pieces. Two-dimensional array ultrasound probes are known. This two-dimensional array ultrasonic probe can easily obtain a three-dimensional ultrasonic image as compared with a one-dimensional array ultrasonic probe configured by dividing a piezoelectric vibrator in a one-dimensional direction, or There is a feature that the focus of the ultrasonic beam can be adjusted electronically. Note that a two-dimensional array ultrasonic probe for the purpose of electronically adjusting the focus of the ultrasonic beam may be referred to as a 1.5-dimensional (1.5D) array ultrasonic probe. In this specification, all array ultrasonic probes having a structure in which a piezoelectric vibrator is divided in a two-dimensional direction are all referred to as a two-dimensional array ultrasonic probe.
[0003]
In the two-dimensional array ultrasonic probe, the upper and lower electrodes of each piezoelectric vibrator piece must be electrically connected to the outside. As a method of connecting this electrode to the outside, the following method is known.
[0004]
In Patent Document 1, a lower electrode of a piezoelectric vibrator piece is formed by using a wiring board having a conductive path connected to an electrode hole (through hole) arranged in a two-dimensional shape on one surface. An external connection is disclosed. In this patent document 1, the lower electrode of the piezoelectric vibrator is fixed to the surface opposite to the conduction path side of the wiring board, and then a cut is made from the upper electrode of the piezoelectric vibrator until reaching the wiring board. After being divided into a plurality of piezoelectric vibrator pieces, the lower electrode of the piezoelectric vibrator piece is led out to the surface on the conduction path side through an electrode hole, and the lower electrode of the piezoelectric vibrator piece is connected to the outside. Note that the upper electrode of one piezoelectric vibrator piece can be connected to the outside through a common electrode formed thereon.
[0005]
FIG. 1 of Patent Document 2 shows a lower electrode (first electrode) of a piezoelectric vibrator piece using a wiring board including a rigid part provided with a through hole and a flexible part having a lead wiring pattern. A two-dimensional array ultrasonic probe in which is connected to the outside is disclosed. In the two-dimensional array ultrasonic probe disclosed in this figure, a common electrode is formed on the upper electrode (second electrode) of the piezoelectric vibrator piece.
[0006]
4 and 5 of Patent Document 2 further include an anisotropic conductive layer in which columnar conductors are arranged between the piezoelectric vibrator piece and the wiring board, and a lower electrode of the piezoelectric vibrator piece and A two-dimensional array ultrasonic probe connected to a wiring board is disclosed. In the two-dimensional array ultrasonic probe disclosed in these drawings, the upper electrode of the piezoelectric vibrator piece seems to be a common electrode. However, in consideration of the description in the specification, the common electrode is a piezoelectric vibrator. It is thought that it is formed on the upper electrode of the piece.
[0007]
FIG. 7 of Patent Document 2 shows a two-dimensional array in which the lower electrodes of the piezoelectric vibrator pieces are connected to the outside via lead-out pads provided at both ends in the direction in which the number of piezoelectric vibrator pieces is arranged. An ultrasound probe is disclosed. Even in the two-dimensional array ultrasonic probe disclosed in this figure, the upper electrode of the piezoelectric vibrator piece seems to be a common electrode. However, in consideration of the description, the common electrode is a piezoelectric vibrator piece. It is thought that it is formed on the upper electrode.
[0008]
[Patent Document 1]
Japanese Patent No. 2948610 [Patent Document 2]
Japanese Patent No. 3288815 [0009]
[Problems to be solved by the invention]
In the two-dimensional array ultrasonic probe, it is desirable that the ultrasonic transmission / reception characteristics of the piezoelectric vibrator pieces exhibit a high degree of homogeneity. However, when the common electrode is formed on the upper electrode of the piezoelectric vibrator piece like the two-dimensional array ultrasonic probe known so far, the thickness of the common electrode tends to be non-uniform, The uniformity of ultrasonic transmission / reception characteristics may be reduced. Accordingly, an object of the present invention is to provide a method for manufacturing a two-dimensional array ultrasonic probe in which ultrasonic transmission / reception characteristics of each piezoelectric vibrator piece have high homogeneity.
[0010]
[Means for Solving the Problems]
This invention exists in the manufacturing method of the two-dimensional array ultrasonic probe which consists of the following processes.
(1) A step of forming an acoustic matching layer on the surface of the upper electrode of the piezoelectric vibrator made of a plate-like piezoelectric body having electrodes on the upper and lower sides.
(2) With respect to the surface of the lower electrode of the piezoelectric vibrator, in a two-dimensional direction, from the surface of the lower electrode toward the upper electrode, the depth is 80 to 95% of the thickness of the plate-like piezoelectric body. A step of dividing the lower electrode and the plate-like piezoelectric body into a plurality of subdivided lower electrode pieces and plate-like piezoelectric vibrator pieces.
(3) Separately prepared electrode terminals of a wiring board having an electrode terminal corresponding to the lower electrode piece of the piezoelectric vibrator and an electric wiring connected to the electrode terminal are respectively connected to the lower electrode piece of the piezoelectric vibrator. Electrically connecting to the lead wire.
(4) A step of forming a sound absorbing layer by curing a curable resin material on the surface of the lower electrode piece of the piezoelectric vibrator.
(5) From the surface of the acoustic matching layer opposite to the piezoelectric vibrator side to the front of the piezoelectric vibrator, a cut is made at a position corresponding to the cut formed in the piezoelectric vibrator, and the cut is filled with resin. Process.
[0011]
A preferred embodiment of the method for producing the two-dimensional array ultrasonic probe of the present invention is shown below.
(1) A step of filling a resin material into the cut of the piezoelectric vibrator is included.
[0012]
The present invention also relates to a plate-like piezoelectric element having electrodes on top and bottom, for the surface of the lower electrode, formed on the two-dimensional directions, toward the upper electrode from the surface of the lower electrode, the plate The lower electrode and the plate-like piezoelectric body are divided into a plurality of subdivided lower electrode pieces and plate-like piezoelectric pieces by a cut extending to a depth of 80 to 95% of the thickness of the piezoelectric member. A piezoelectric substrate, a wiring board having an electrode terminal electrically connected to each of the lower electrode pieces of the piezoelectric vibrator via lead wires, and an electric wiring connected to each of the electrode terminals, There is also a two-dimensional array ultrasonic probe including a sound absorbing layer formed on the surface of the lower electrode piece and an acoustic matching layer formed on the surface of the upper electrode of the piezoelectric vibrator.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A method for manufacturing a two-dimensional array ultrasonic probe of the present invention will be described with reference to the accompanying drawings.
[0014]
First, as shown in FIG. 1, the first acoustic matching layer 5 and the second acoustic matching are formed on the surface of the upper electrode 1 of the piezoelectric vibrator 4 composed of the plate-like piezoelectric body 3 having the electrodes 1 and 2 on the upper and lower sides. An acoustic matching layer 7 composed of the layer 6 is formed. In the example shown in FIG. 1, the size of the acoustic matching layer 7 is larger than the size of the piezoelectric vibrator 4 in order to secure a space for taking out the upper electrode 1 of the piezoelectric vibrator 4 to the outside. The size of the acoustic matching layer 7 is not particularly limited and may be the same as the size of the piezoelectric vibrator 4.
[0015]
In the present invention, the material of the piezoelectric vibrator 4 and the acoustic matching layer 7 is not particularly limited, and various materials used for ordinary ultrasonic probes can be used. Examples of the material of the upper and lower electrodes 1 and 2 of the piezoelectric vibrator 4 include metals such as gold and silver. Examples of the material of the plate-like piezoelectric body 3 include piezoelectric ceramics such as lead zirconate titanate (PZT). Examples of the material of the acoustic matching layer 7 include resin materials such as epoxy resin and urethane resin. The acoustic matching layer 7 does not necessarily have to be two layers, and may be a single layer or three or more layers.
[0016]
As a method for forming the acoustic matching layer 7, a method of pouring an uncured curable resin material on the upper electrode 1 and then curing it, or preparing a resin material sheet formed in a sheet shape in advance is used. A known method such as a method of adhering to the electrode 1 with an adhesive (eg, an epoxy resin adhesive) can be employed.
[0017]
Next, as shown in FIG. 2 (a), the piezoelectric vibrator 4 is turned upside down, and the piezoelectric vibrator 4 is formed with an acoustic matching layer for transmitting / receiving ultrasonic waves (ultrasonic transmission / reception part). ) In order to divide into 4a and the part (upper electrode connection part) 4b in which the acoustic matching layer for ensuring the space which makes it easy to connect an upper electrode outside is not formed (upper electrode connection part) 4b, it is an upper electrode from the surface of the lower electrode 2 A cut 8 a corresponding to the size of the acoustic matching layer 7 is made toward 1. Instead of making the cut 8a, the lower electrode of the upper electrode connection portion 4b may be scraped off.
[0018]
Subsequently, as shown in FIG. 2B, the lower electrode in the two-dimensional direction (X direction and Y direction in FIG. 2B) with respect to the surface of the lower electrode 2 of the piezoelectric vibrator 4. A notch 8b is made from the surface of 2 toward the upper electrode 1 to divide the lower electrode 2 and the plate-like piezoelectric body 3 into a plurality of subdivided lower electrode pieces 2a and plate-like piezoelectric piece 3a. That is, the notch 8b is inserted to divide the ultrasonic wave transmitting / receiving portion 4a of the piezoelectric vibrator 4 into a plurality of piezoelectric vibrator pieces 4a ′ and the upper electrode connection portion 4b into a plurality of upper electrode connection piece 4b ′. In FIG. 2B, the ultrasonic transmission / reception portion 4a is divided into five piezoelectric vibrator pieces 4a ′ in each of the X direction and the Y direction. There are no particular restrictions.
[0019]
The cuts 8a and 8b to be inserted into the piezoelectric vibrator 4 can be formed using a known cutting device such as a dicing saw. When forming the notch 8a, it is preferable to set the depth so that it does not exceed 95% of the thickness of the plate-like piezoelectric body 3 of the piezoelectric vibrator 4. If the thickness of the plate-like piezoelectric body is set to exceed 95%, the upper electrode 1 may be cut by mistake. When the cut 8b is formed, the depth is 95% or less of the thickness of the plate-like piezoelectric body 3 of the piezoelectric vibrator 4 and 80% of the thickness of the plate-like piezoelectric body 3 as in the case of the cut 8a. Set as above. When the depth of the cut 8b is less than 80% of the thickness of the plate-like piezoelectric body, crosstalk between the piezoelectric vibrator pieces tends to occur.
[0020]
Next, as shown in FIG. 3, in order to further reduce crosstalk between the piezoelectric vibrator pieces, the notches 8 a and 8 b are filled with a resin 9. As the resin 9, an epoxy resin, a urethane resin, and a silicone resin can be used.
[0021]
Next, as shown in FIG. 4, an electrode of a wiring board 12 that has a separately prepared electrode terminal 10 corresponding to the lower electrode piece 2 a of the piezoelectric vibrator 4 and an electric wiring 11 connected to the electrode terminal 10. The terminal 10 is electrically connected to each of the lower electrode pieces 2 a of the piezoelectric vibrator 4 via lead wires 13.
[0022]
Aluminum or gold can be used as the material of the lead wire 13. In particular, gold is preferable. As a method of forming the lead wire 13, a wire bonding method can be used.
[0023]
As the wiring board 12, the same wiring board as that used in a normal ultrasonic probe such as a flexible printed wiring board can be used.
[0024]
The connection pattern between the lower electrode piece 2a of the piezoelectric vibrator and the wiring board 12 can be appropriately set according to the purpose of use of the two-dimensional array ultrasonic probe. Hereinafter, the connection pattern between the lower electrode piece of the piezoelectric vibrator and the wiring board will be described with reference to FIGS.
[0025]
FIG. 5 is a plan view of an example in which the piezoelectric vibrator is viewed from the lower electrode side in a state in which the lower electrode piece of the piezoelectric vibrator and the wiring board are connected by a lead wire. In FIG. 5, the wiring board includes an electrode board 12a having two electrode terminals 10a and 10b, and a wiring board 12b having three electrode terminals 10c, 10d and 10e. Of the five lower electrode piece of the piezoelectric vibrator 4, the lower side electrode pieces 2a ₁ is connected to the electrode terminals 10a by a lead wire 13a, the lower electrode strips 2a ₂ connected to the electrode terminal 10b via a lead wire 13b The lower electrode piece 2a ₃ is connected to the electrode terminal 10e by a lead wire 13e, and the lower electrode piece 2a ₅ is connected to the electrode terminal 10d by a lead wire 13d. In the two-dimensional array ultrasonic probe having this connection pattern, electrical energy can be supplied to each of the lower electrodes 2a ₁ , 2a ₂ , 2a ₃ , 2a ₄ , 2a ₅ independently. Therefore, this connection pattern is mainly used for a two-dimensional array ultrasonic probe for the purpose of obtaining a three-dimensional ultrasonic image.
[0026]
FIG. 6 is a plan view of another example in which the piezoelectric vibrator is viewed from the lower electrode side in a state in which the lower electrode piece of the piezoelectric vibrator and the wiring board are connected by lead wires. In FIG. 6, the wiring board is composed of an electrode board 12a having two electrode terminals 10a and 10b and a wiring board 12b having two electrode terminals 10c and 10d. Of the five lower electrode piece of the piezoelectric vibrator 4, the lower side electrode pieces 2a ₁ is connected to the electrode terminals 10a by a lead wire 13a, the lower electrode strips 2a ₂ connected to the electrode terminal 10b via a lead wire 13b , the lower electrode strip 2a ₃ and the electrode terminal 10c connected by a lead wire 13c, the lower electrode strip 2a ₅ connected to the electrode terminal 10b via a lead wire 13b connected to the lower electrode strips 2a ₂ by a lead wire 13d, The lower electrode piece 2a ₅ is connected to the electrode terminal 10e by a lead wire 13e. In the two-dimensional array ultrasonic probe having this connection pattern, electric energy can be simultaneously supplied to the lower electrode piece 2a ₂ and the lower electrode piece 2a ₄ . Therefore, this connection pattern is mainly used in a two-dimensional array ultrasonic probe for the purpose of electronically adjusting the focus of an ultrasonic beam.
[0027]
FIG. 7 is a plan view of still another example in which the piezoelectric vibrator is viewed from the lower electrode side in a state in which the lower electrode piece of the piezoelectric vibrator and the wiring board are connected by lead wires. In FIG. 7, the wiring board includes an electrode board 12a having two electrode terminals 10a and 10b, and a wiring board 12b having one electrode terminal 10c. Of the five lower electrode piece of the piezoelectric vibrator 4, the lower side electrode pieces 2a ₁ is connected to the electrode terminals 10a by a lead wire 13a, the lower electrode strips 2a ₂ connected to the electrode terminal 10b via a lead wire 13b The lower electrode piece 2a ₃ is connected to the electrode terminal 10c by the lead wire 13c, the lower electrode piece 2a ₄ is connected to the electrode terminal 10d by the lead wire 13d, and the electrode terminal is connected by the lead wire 13b together with the lower electrode piece 2a ₂ connect to 10b, the lower electrode strip 2a ₅ is connected to the electrode terminal 10b via a lead wire 13b connected to the lower side electrode pieces 2a ₂ from the lead wire 13e. A two-dimensional array ultrasonic probe having such a connection pattern is advantageously used particularly when the focus is to electronically adjust the focus of the ultrasonic beam. In the two-dimensional array ultrasonic probe having this connection pattern, electric energy is simultaneously supplied to the lower electrode piece 2a ₂ and the lower electrode piece 2a ₄ , and the lower electrode piece 2a ₁ and the lower electrode piece 2a _5. be able to. Therefore, this connection pattern is mainly used in a two-dimensional array ultrasonic probe for the purpose of electronically adjusting the focus of an ultrasonic beam.
[0028]
When the electrode terminal of the wiring board is connected to the lower electrode piece of the piezoelectric vibrator as described above, an uncured curable resin material is applied to the surface of the lower electrode piece of the piezoelectric vibrator as shown in FIG. The sound absorbing layer 14 is formed by curing, and then the upper and lower sides of the piezoelectric vibrator 4 are returned to the original, and the piezoelectric vibration from the surface opposite to the piezoelectric vibrator 4 side of the acoustic matching layer 7 to the front of the piezoelectric vibrator. A notch 15 is made at a position corresponding to the notch 8 b formed in the child, and the notch 15 is filled with the resin 16.
[0029]
An epoxy resin can be used as the curable resin for forming the sound absorbing layer.
[0030]
The cut 15 of the acoustic matching layer 7 is preferably set to a depth of 80 to 95% of the thickness of the acoustic matching layer 7, similarly to the cut 8 b of the piezoelectric vibrator.
[0031]
FIG. 9 shows a cutaway perspective view of an example of the two-dimensional array ultrasonic probe manufactured as described above. In FIG. 9, the two-dimensional array ultrasonic probe is composed of a plate-like piezoelectric body 3 having electrodes 1 and 2 on the upper and lower sides, and is formed in the two-dimensional direction with respect to the surface of the lower electrode 2. The lower electrode 2 and the plate-like piezoelectric body 3 are formed by notches 8 a and 8 b extending from the surface from the lower electrode 2 toward the upper electrode 1 to a depth of 80 to 95% of the thickness of the plate-like piezoelectric body 3. Is divided into a plurality of subdivided lower electrode pieces 2a and plate-like piezoelectric piece 3a (that is, the piezoelectric vibrator 4 has a plurality of piezoelectric vibrator pieces 4a 'and an upper electrode connecting piece. 4b ′) and the electrode terminal 10 electrically connected to each of the lower electrode piece 2a of the piezoelectric vibrator 4 and the piezoelectric vibrator 4 via the lead wire 13 and the electricity connected to each of the electrode terminals. A wiring board 12 having wiring 11 is formed on the surface of the lower electrode piece 2a of the piezoelectric vibrator. Sound absorbing layer 14, and is composed of an acoustic matching layer 7 of the first acoustic matching layer 5 formed on the surface of the upper electrode 1 of the piezoelectric vibrator second acoustic matching layer 6.
[0032]
The cuts 8a and 8b are filled with a resin 9 in order to reduce crosstalk between the piezoelectric vibrator pieces. Further, the acoustic matching layer 7 is formed with a cut 15, and the cut 15 is also filled with a resin 16.
[0033]
【The invention's effect】
In the method for manufacturing a two-dimensional array ultrasonic probe of the present invention, the upper electrode of the piezoelectric vibrator is not cut, so that it is not necessary to form a common electrode on the upper electrode of the piezoelectric vibrator piece. Therefore, in the two-dimensional array ultrasonic probe manufactured by the method of the present invention, the ultrasonic transmission / reception characteristics of each piezoelectric vibrator piece have a high degree of homogeneity. Further, in the manufacturing method of the present invention, the step of forming the common electrode that is necessary in the conventional manufacturing method can be omitted, and the productivity of the two-dimensional array ultrasonic probe is increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of a piezoelectric vibrator in which an acoustic matching layer is formed on the surface of an upper electrode in accordance with the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
FIG. 2 is a perspective view of a piezoelectric vibrator showing a state in which the piezoelectric vibrator of FIG. 1 has been cut in accordance with the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
3 is a cross-sectional view of a piezoelectric vibrator showing a state in which a resin is filled in the notch of the piezoelectric vibrator of FIG. 2 in accordance with the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
4 is a cross-sectional view of a piezoelectric vibrator showing a state in which the lower electrode piece of the piezoelectric vibrator of FIG. 3 and a wiring board are connected by a lead wire in accordance with the method for manufacturing a two-dimensional array ultrasonic probe of the present invention. FIG.
FIG. 5 shows a state in which the lower electrode piece of the piezoelectric vibrator and the wiring board are connected by a lead wire according to the method for manufacturing a two-dimensional array ultrasonic probe of the present invention. It is the top view of an example seen.
FIG. 6 shows a state in which the lower electrode piece of the piezoelectric vibrator and the wiring board are connected to each other by a lead wire according to the manufacturing method of the two-dimensional array ultrasonic probe of the present invention. It is a top view of another example seen.
FIG. 7 shows a state in which a wiring board and a lower electrode piece of a piezoelectric vibrator are connected by a lead wire from the lower electrode side according to the method for manufacturing a two-dimensional array ultrasonic probe of the present invention. It is the top view of another example seen.
8 is a diagram illustrating a method of manufacturing a two-dimensional array ultrasonic probe according to the present invention, in which a sound absorbing layer is formed on the surface of the lower electrode piece of the piezoelectric vibrator of FIG. It is sectional drawing of the piezoelectric vibrator which shows the state filled with resin.
FIG. 9 is a cutaway perspective view of an example of a two-dimensional array ultrasonic probe manufactured according to the method of manufacturing a two-dimensional array ultrasonic probe of the present invention.
[Explanation of symbols]
1 upper electrode 2 lower electrode _{2a, 2a 1, 2a 2,} 2a 3, 2a 4, 2a 5 lower electrode piece 3 piezoelectric plate 3a shaped piezoelectric member 4 piezoelectric vibrators 4a ultrasonic transmitting and receiving portion 4a 'piezoelectric Vibrator piece 4b Upper electrode connection portion 4b 'Upper electrode connection portion piece 5 First acoustic matching layer 6 Second acoustic matching layer 7 Acoustic matching layer 8a, 8b Notch 9 Resin 10, 10a, 10b, 10c, 10d, 10e Electrode terminal 11 Electrical wiring 12 Wiring boards 13, 13a, 13b, 13c, 13d, 13e Lead wire 14 Sound absorbing layer 15 Notch 16 Resin

Claims (3)

A method for producing a two-dimensional array ultrasonic probe comprising the following steps:
(1) forming an acoustic matching layer on a surface of an upper electrode of a piezoelectric vibrator made of a plate-like piezoelectric body provided with electrodes on the upper and lower sides;
(2) With respect to the surface of the lower electrode of the piezoelectric vibrator, in a two-dimensional direction, from the surface of the lower electrode toward the upper electrode, the depth is 80 to 95% of the thickness of the plate-like piezoelectric body. A step of dividing the lower electrode and the plate-like piezoelectric body into a plurality of subdivided lower electrode pieces and plate-like piezoelectric vibrator pieces;
(3) Separately prepared electrode terminals of a wiring board having an electrode terminal corresponding to the lower electrode piece of the piezoelectric vibrator and an electric wiring connected to the electrode terminal are respectively connected to the lower electrode piece of the piezoelectric vibrator. Electrically connecting to the lead wire through a lead wire ;
(4) forming a sound absorbing layer by curing a curable resin material on the surface of the lower electrode piece of the piezoelectric vibrator ; and
(5) Cut from the surface of the acoustic matching layer opposite to the piezoelectric vibrator to the front of the piezoelectric vibrator at a position corresponding to the cut formed in the piezoelectric vibrator, and fill the cut with resin. Process .   The method for manufacturing a two-dimensional array ultrasonic probe according to claim 1, further comprising a step of filling a resin material into the notch of the piezoelectric vibrator. It consists of a plate-shaped piezoelectric body with electrodes on the top and bottom, and is formed in the two-dimensional direction with respect to the surface of the lower electrode, and the thickness of the plate-shaped piezoelectric body from the surface of the lower electrode toward the upper electrode A piezoelectric vibrator in which the lower electrode and the plate-like piezoelectric body are divided into a plurality of subdivided lower electrode pieces and plate-like piezoelectric pieces by a cut extending to a depth of 80 to 95% of A wiring board having an electrode terminal electrically connected to each of the lower electrode pieces of the piezoelectric vibrator via a lead wire and an electric wiring connected to each of the electrode terminals, and a surface of the lower electrode piece of the piezoelectric vibrator A two-dimensional array ultrasonic probe comprising a sound absorbing layer formed on the surface of the piezoelectric transducer and an acoustic matching layer formed on the surface of the upper electrode of the piezoelectric vibrator.

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