JP4071083B2 - Manufacturing method of two-dimensional array ultrasonic probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a two-dimensional array ultrasonic probe.
[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 conductive path side of the wiring board, and then a notch reaching the wiring board from the upper electrode of the piezoelectric vibrator is made. 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 conductive 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 portion provided with a through hole and a flexible portion having a lead-out wiring pattern. A two-dimensional array ultrasonic probe in which is connected to the outside is disclosed. Also 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 figures, the upper electrode of the piezoelectric vibrator piece seems to be a common electrode, but in consideration of the description, 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 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 piece.
(3) was separately prepared, on one surface, it has a plurality of electrode terminals corresponding to, respectively Re its bottom electrode piece of the piezoelectric vibrator, on the other surface, is connected to each of the electrode terminals A step of electrically connecting each electrode terminal of the wiring board having electric wiring to each of the lower electrode pieces of the piezoelectric vibrator.
(4) A step of forming a sound absorbing material on the surface of the wiring board opposite to the piezoelectric vibrator side.
(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 includes a plate-like piezoelectric body having electrodes on the upper and lower sides, and is formed in a two-dimensional direction with respect to the surface of the lower electrode, from the surface from the lower electrode toward the upper electrode. 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. An electrical terminal electrically connected to each of the electrode terminals on one surface, and an electrode terminal electrically connected to each of the lower electrode piece of the piezoelectric vibrator and the piezoelectric vibrator A two-dimensional array ultrasonic probe comprising a wiring board having a wiring board, a sound absorbing material formed on the surface opposite to the piezoelectric vibrator side of the wiring board, and an acoustic matching layer formed on the upper electrode of the piezoelectric vibrator. is there.
[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 smaller than the size of the piezoelectric vibrator 4 in order to secure a space for connecting 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 of 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 into a sheet shape in advance, 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 made, the ultrasonic transmission / reception portion 4a of the piezoelectric vibrator 4 is divided into a plurality of piezoelectric vibrator pieces 4a ', and the upper electrode connection portion 4b is divided into a plurality of upper electrode connection pieces 4b'. To do. 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 to be 95% or less of the thickness of the plate-like piezoelectric body 3 of the piezoelectric vibrator 4. If it is set to exceed 95% of the thickness of the plate-like piezoelectric body, 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, the electrode terminal 10 corresponding to each of the lower electrode pieces of the piezoelectric vibrator is provided on one surface prepared separately, and the electrode terminal 10 is provided on the other surface. Each of the electrode terminals 10 of the wiring board 12 having the electric wiring 11 connected thereto is electrically connected to each of the lower electrode pieces 2a of the piezoelectric vibrator piece 4a ′ by a solder dump 13.
[0022]
For the connection between the lower electrode piece 2a and the electrode terminal 10, a conductive material such as cream solder, a conductive adhesive, and an anisotropic conductive adhesive can be used in addition to the solder dump. In the case of using an adhesive such as a conductive adhesive and an anisotropic conductive adhesive, in order to prevent a void (gap) between the piezoelectric vibrator 4 and the wiring board 12, a wiring board is previously provided. A plurality of through-holes (not shown) are opened in 12 and the piezoelectric vibrator 4 and the wiring board 12 are bonded together, and then vacuum degassing is performed, so that a gap between the piezoelectric vibrator 4 and the wiring board 12 is obtained. It is preferable to remove air.
[0023]
The wiring board 12 uses a translucent resin film in which the electrode terminal 10 can be seen through the substrate (base) from the surface on the electric wiring side in order to facilitate alignment between the electrode terminal 10 and the lower electrode piece 2a. It is preferable to use a flexible printed circuit board.
[0024]
The pattern of the electrical wiring 11 on the wiring board 12 is appropriately set according to the purpose of use of the two-dimensional array ultrasonic probe. Hereinafter, the electrical wiring pattern of the wiring board for the two-dimensional array ultrasonic probe will be described with reference to FIGS.
[0025]
FIG. 5 is a plan view of an example showing an electrical wiring pattern of the wiring board, FIG. 5A is a plan view of the surface of the wiring board on the electrode terminal side, and FIG. 5B is a plan view of the wiring board. It is a top view of the surface by the side of electrical wiring. In FIG. 5, a rectangle indicated by a broken line corresponds to a lower electrode piece of the piezoelectric vibrator. In the wiring board 12a of FIG. 5, the electrode terminals 10a, 10b, 10c, 10d, and 10e are connected to the outside by electric wirings 11a, 11b, 11c, 11d, and 11e, respectively. This wiring board 11a is mainly used for a two-dimensional array ultrasonic probe for obtaining a three-dimensional ultrasonic image.
[0026]
6 is a plan view of another example showing the electrical wiring pattern of the wiring board, FIG. 6 (a) is a plan view of the surface of the wiring board on the electrode terminal side, and FIG. 6 (b) is a wiring diagram. It is a top view of the surface by the side of the electrical wiring of a board | substrate. Also in FIG. 6, the rectangle indicated by the broken line corresponds to the lower electrode piece of the piezoelectric vibrator as in the case of FIG. 5. The wiring board 12b of FIG. 6 is the same as the wiring of FIG. 5 except that the electrode terminal 11b and the electrode terminal 11d adjacent to the center electrode terminal 10c are connected by the electric wiring 11b and connected to the outside by one electric wiring 11d. The configuration is the same as that of the substrate. This wiring board 12b is mainly used for a two-dimensional array ultrasonic probe for the purpose of electronically adjusting the focus of the ultrasonic beam.
[0027]
FIG. 7 is a plan view of still another example showing the electrical wiring pattern of the wiring board, FIG. 7A is a plan view of the surface of the wiring board on the electrode terminal side, and FIG. It is a top view of the surface by the side of the electrical wiring of a wiring board. Also in FIG. 7, the rectangle indicated by the broken line corresponds to the lower electrode piece of the piezoelectric vibrator, as in the case of FIGS. 5 and 6. The wiring board 12c of FIG. 7 is the same as the wiring board of FIG. 6 except that the electrode terminals 11a and the electrode terminals 11e located at both ends are connected by the electric wiring 11a and connected to the outside by one electric wiring 11e. It is a configuration. The wiring board 12c is also used for a two-dimensional array ultrasonic probe mainly for electronically adjusting the focus of the ultrasonic beam, similarly to the wiring board of FIG.
[0028]
As described above, when the electrode terminal of the wiring board is connected to the lower electrode piece of the piezoelectric vibrator, the sound absorbing material 14 is formed on the surface opposite to the piezoelectric vibrator 4 side of the wiring board 12 as shown in FIG. Next, the upper and lower sides of the piezoelectric vibrator 4 are returned to the original, and the notch 8b formed in the piezoelectric vibrator from the surface opposite to the piezoelectric vibrator 4 side of the acoustic matching layer 7 to the front of the piezoelectric vibrator is supported. A cut 15 is made at the position where the cut is made, and a resin 16 is filled in the cut.
[0029]
The sound absorbing material 14 is formed by pouring an uncured curable resin (e.g., epoxy resin or urethane resin) onto the wiring substrate 12 and then curing the sound absorbing material 14, or a sound absorbing material molded into a predetermined shape. A publicly known method such as a method of preparing (example: ferrite rubber) in advance and bonding it onto the wiring board 12 with an adhesive (eg, epoxy resin adhesive) can be employed.
[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 in the same manner as the cut of the piezoelectric vibrator.
[0031]
Examples of the resin 16 that fills the cut 15 of the acoustic matching layer 7 include an epoxy resin, a urethane resin, and a silicone resin, as in the case of filling the cut of the piezoelectric vibrator.
[0032]
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 provided with electrodes 1 and 2 on the upper and lower sides, and is formed on the surface of the lower electrode 2 in a two-dimensional direction. The lower electrode 2 and the plate-like piezoelectric body 3 are divided into a plurality of subdivided lower electrode pieces 2a and plate-like piezoelectric piece by the notches 8a and 8b extending to a depth of 80 to 95% of the thickness of 3. Of the piezoelectric vibrator 4 and the lower electrode piece 2a of the piezoelectric vibrator 4 that are divided into 3a (that is, divided into a plurality of piezoelectric vibrator pieces 4a 'and an upper electrode connecting piece 4b'). A wiring board 12 having an electrode terminal 10 electrically connected to each electrode on one surface and an electric wiring 11 electrically connected to each of the electrode terminals on the other surface, the piezoelectric vibrator side of the wiring board Is formed on the sound absorbing material 14 formed on the surface opposite to the upper surface of the piezoelectric vibrator and the upper electrode 1 of the piezoelectric vibrator. It was, and a acoustic matching layer 7 and the first acoustic matching 5 made from the second acoustic matching layer 6.
[0033]
In order to reduce crosstalk between the piezoelectric vibrator pieces, the cuts 8a and 8b are filled with a resin 9. Further, the acoustic matching layer 7 is formed with a cut 15, and the cut 15 is also filled with a resin 16.
[0034]
【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 a wiring board is connected to a lower electrode piece of the piezoelectric vibrator of FIG. 3 in accordance with the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
FIG. 5 is a diagram showing an example of an electrical wiring pattern of a wiring board that can be used in the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
FIG. 6 is a diagram showing another example of an electrical wiring pattern of a wiring board that can be used in the method for manufacturing a two-dimensional array ultrasonic probe of the present invention.
FIG. 7 is a view showing still another example of the electric wiring pattern of the wiring board that can be used in the method of manufacturing the two-dimensional array ultrasonic probe of the present invention.
8 is a diagram illustrating a method for manufacturing a two-dimensional array ultrasonic probe according to the present invention. In FIG. 4, a sound absorbing material is formed on the wiring board of the piezoelectric vibrator shown in FIG. It is sectional drawing of the piezoelectric vibrator which shows the state which carried out.
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]
DESCRIPTION OF SYMBOLS 1 Upper electrode 2 Lower electrode 2a Lower electrode piece 3 Plate-shaped piezoelectric material 3a Plate-shaped piezoelectric material piece 4 Piezoelectric vibrator 4a Ultrasonic wave transmission / reception part 4a 'Piezoelectric vibrator piece 4b Upper electrode connection part 4b' Upper electrode connection part piece 5 Sound absorbing material 6 First acoustic matching layer 7 Second acoustic matching layer 8a, 8b Notch 9 Resin 10, 10a, 10b, 10c, 10d, 10e Electrode terminals 11, 11a, 11b, 11c, 11d, 11e Electrical wiring 12 Wiring board 13 Solder bump 14 Sound absorbing material 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 pieces;
(3) was separately prepared, on one surface, it has a plurality of electrode terminals corresponding to, respectively Re its bottom electrode piece of the piezoelectric vibrator, on the other surface, is connected to each of the electrode terminals Electrically connecting each electrode terminal of the wiring board having electrical wiring to each of the lower electrode pieces of the piezoelectric vibrator ;
(4) forming a sound absorbing material on the surface of the wiring board opposite to the piezoelectric vibrator side ;
(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 .   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 and wiring having an electrode terminal electrically connected to each of the lower electrode pieces of the piezoelectric vibrator on one surface and an electric wiring electrically connected to each of the electrode terminals on the other surface A two-dimensional array ultrasonic probe comprising a sound absorbing material formed on a surface of a substrate opposite to a piezoelectric vibrator side, and an acoustic matching layer formed on an upper electrode of the piezoelectric vibrator.

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