JP4255364B2 - Manufacturing method of two-dimensional array type ultrasonic probe - Google Patents

Description

  The present invention relates to a two-dimensional array type ultrasonic probe and a manufacturing method thereof.

A two-dimensional structure in which a piezoelectric vibrator made of a plate-like piezoelectric body having electrode layers on both surfaces is divided into two directions, a length direction and a width direction, as an ultrasonic probe for a medical ultrasonic diagnostic apparatus An array-type ultrasonic probe is known.
A two-dimensional array type ultrasonic probe is generally a laminate of an acoustic matching layer and divided piezoelectric vibrators, and for electrically connecting the divided piezoelectric vibrators to the outside for each divided unit. Consists of wiring tools. Usually, the acoustic matching layer side electrodes of the divided piezoelectric vibrators are electrically connected to each other and used as a common electrode. The other electrode layer is wired by a wiring tool for each division unit so that electric energy can be supplied for each division unit.

  Patent Document 1 discloses a two-dimensional array type ultrasonic probe in which an electrode layer on a wiring side is connected to a wiring tool including a rigid portion provided with a through hole and a flexible portion having a lead-out wiring pattern. Has been.

The two-dimensional array type ultrasonic probe is a three-dimensional ultrasonic image as compared with a one-dimensional array ultrasonic probe having a configuration in which a piezoelectric vibrator is divided in one of the length direction and the width direction. Can be easily obtained, or the focus of the ultrasonic beam can be adjusted electronically. Note that a two-dimensional array type ultrasonic probe for the purpose of electronically adjusting the focus of the ultrasonic beam is sometimes referred to as a 1.5-dimensional (1.5D) array ultrasonic probe. In this specification, all array ultrasonic probes having a configuration in which a piezoelectric vibrator is divided in a two-dimensional direction are all referred to as a two-dimensional array type ultrasonic probe.
Japanese Patent No. 3288815

  In a two-dimensional array type ultrasonic probe used in a medical ultrasonic diagnostic apparatus, it is required to increase the frequency of ultrasonic signals to be transmitted and received. The frequency of the ultrasonic signal transmitted and received by the ultrasonic probe depends on the thickness of the piezoelectric vibrator. Generally, the thinner the piezoelectric vibrator, the higher the frequency of the ultrasonic signal transmitted and received. is there. Therefore, in order to meet the demand for higher frequencies, it is necessary to reduce the thickness of the piezoelectric vibrator.

On the other hand, the transmission / reception efficiency (electric-acoustic conversion efficiency) of the ultrasonic signal of the piezoelectric vibrator depends on the S / T ratio between the length S of the short side of the piezoelectric vibrator and the thickness T of the piezoelectric vibrator. Are known. Generally, when the S / T ratio is in the range of 0.3 to 0.7, it is said that the transmission / reception efficiency of ultrasonic signals is high.
Therefore, in order to efficiently transmit and receive high-frequency ultrasonic signals, it is necessary to reduce the size of the division unit (particularly, the length of the short side) with the thickness of the piezoelectric vibrator.

  In order to efficiently transmit and receive high-frequency ultrasonic signals, when the piezoelectric vibrator is divided so that the S / T ratio is 0.3 to 0.7, the ultrasonic transmission / reception area of each division unit is reduced. For this reason, in order to increase the transmission / reception area of the ultrasonic signal of the entire two-dimensional array type ultrasonic probe, it is necessary to increase the number of division units of the piezoelectric vibrator. However, in the two-dimensional array type ultrasonic probe, since the wiring-side electrode layer must be connected to the wiring tool for each division unit, there is a problem that the manufacturing becomes complicated when the number of division units increases. .

  Accordingly, an object of the present invention is to provide a two-dimensional array-type ultrasonic probe that can efficiently transmit and receive high-frequency ultrasonic signals in a wide area and that is easy to manufacture, and a method for manufacturing the same. .

The present invention relates to an acoustic matching layer, an acoustic matching layer side electrode layer, and a laminate in which a composite of a plate-like piezoelectric body divided for each wiring terminal unit and a wiring side electrode layer is laminated in this order, and the laminate A two-dimensional array-type ultrasonic probe including a wiring tool having an electrode terminal electrically connected to each wiring terminal of a wiring side electrode layer of the body, wherein each complex of each wiring terminal unit is adjacent to each other A gold bump, solder, in which the wiring-side electrode layer of each wiring terminal unit is provided with a separate electrode layer provided for each of the prism-shaped divided composites. It is formed by electrically connecting with a conductor selected from the group consisting of a bump, a conductive paste, a lead copper foil, and a lead wire, and the prismatic divided composite is a side that is a side adjacent to each other. Side length L and the side adjacent to other wiring terminal units The ratio L / S to the short side length S is in the range of 1 to 100, and the total thickness of the short side length S, the acoustic matching layer side electrode, the plate-like piezoelectric body, and the wiring side electrode layer the ratio S / T of the T is on the manufacturing method of the two-dimensional array type ultrasonic probe area by near 0.3 to 0.7.

Preferred embodiments of the two-dimensional array type ultrasonic probe obtained by the production method of the present invention are shown below.
(1) The divided composites adjacent to each other are connected to each other by the piezoelectric material at a portion where the bottom surface in contact with the acoustic matching layer electrode reaches a portion of 5 to 20% of the thickness of the plate-like piezoelectric material.
(2) The acoustic matching layer is divided corresponding to each wiring terminal unit composite.

That is, the present invention comprises the following steps, in the manufacturing method of the two-dimensional array type ultrasonic probe of the present invention.
(1) A step of laminating an acoustic matching layer on the surface of one electrode layer of a piezoelectric vibrator having a thickness T made of a plate-like piezoelectric body having electrode layers on both surfaces;
(2) Each of the piezoelectric vibrators is subdivided from the other electrode layer side so that the long side of the upper surface is L and the short side is S along the length direction and width direction of the piezoelectric vibrator. A step of forming a prismatic divided composite by cutting a plurality of cuts to a portion close to the surface of the other electrode layer;
(3) A conductor selected from the group consisting of a gold bump, a solder bump, a conductive paste, a lead copper foil, and a lead wire, in which adjacent divided composites are separately prepared so as to straddle the side having the length L. Electrically connecting and forming a composite of a plate-like piezoelectric body divided for each wiring terminal and the wiring-side electrode layer; and
(4) A step of connecting each of the wiring-side electrode layers of the composite to each of the electrode terminals of the wiring tool prepared separately.

The present invention also resides in a method for manufacturing the two-dimensional array type ultrasonic probe of the present invention, including the following steps.
(1) A step of laminating an acoustic matching layer on the surface of one electrode layer of a piezoelectric vibrator having a thickness T made of a plate-like piezoelectric body having electrode layers on both surfaces;
(2) From the other electrode layer side of the piezoelectric vibrator, the length of one side of the upper surface is L along the length direction and width direction of the piezoelectric vibrator, and the length of the side adjacent to this side A step of forming a rectangular prism-shaped composite by inserting a plurality of cuts that are subdivided so as to be an integral multiple of S up to a portion close to the surface of the other electrode layer;
(3) An electrically conductive material selected from the group consisting of gold bumps, solder bumps, conductive paste, lead copper foil, and lead wires, in which adjacent composites are separately prepared so as to straddle the side having the length L. Connecting to:
(4) A rectangular prismatic composite is divided into length S along a side having a length of L, and a composite of a plate-like piezoelectric body and a wiring-side electrode layer divided for each wiring unit is obtained. Forming; and
(5) A step of connecting each of the wiring-side electrode layers of the composite to each of the electrode terminals of the wiring tool prepared separately.

In the two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention, the composite of the wiring terminal unit is composed of two or more prismatic divided composites. It can be arbitrarily prepared depending on the number of connected columnar divided composites. The prismatic divided composite has a ratio L / S between the length L of the long side and the length S of the short side which is the side adjacent to the other wiring terminal unit in the range of 1 to 100, The ratio S / T of the short side length S to the total thickness (piezoelectric vibrator thickness) T of the acoustic matching layer side electrode, the plate-like piezoelectric body, and the wiring side electrode layer is 0.3 to 0.7. Since it is in the range, the transmission / reception efficiency (electric-acoustic conversion efficiency) of the ultrasonic signal is increased. Therefore, the two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention can efficiently transmit and receive high-frequency ultrasonic signals in a wide area.
In addition, according to the manufacturing method of the present invention, the two-dimensional array type ultrasonic probe of the present invention can be industrially advantageously manufactured.

The method for producing a two-dimensional array type ultrasonic feeler element of the present invention with reference to the accompanying drawings will be described.

FIG. 1 is a perspective view of an example of a two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention.
FIG. 2 is a perspective view of the two-dimensional array type ultrasonic probe shown in FIG. 1 as viewed from the wiring-side electrode layer side. In FIG. 2, reference numeral 7 (sound absorbing material) in FIG. 1 is omitted.
1 and 2, the two-dimensional array type ultrasonic probe includes an acoustic matching layer composed of a first acoustic matching layer 1 and a second acoustic matching layer 2, an acoustic matching layer side electrode layer 3, and a plate-like piezoelectric element. A laminated body in which the composite body 6 of the body 4 and the wiring-side electrode layer 5 is laminated in this order, and wiring terminals 12 electrically connected to each wiring terminal unit of the wiring-side electrode layer 5 of the laminated body; And two printed wiring boards 14a and 14b having wiring 13 connected to the wiring terminals. A sound absorbing material 7 is laminated on the surface of the wiring side electrode layer 5 opposite to the plate-like piezoelectric body 4 side.

The composite 6 is divided for each wiring terminal unit (basic unit for transmitting and receiving an ultrasonic signal). The divided composite terminals 6 a of the wiring terminals are adjacent to each other and are electrically connected by the conductor 8. It is comprised from the two prismatic division | segmentation composite bodies 9a and 9b connected in general (refer FIG. 2). The number of prismatic divided composites constituting the composite 6a in units of wiring terminals is preferably 2 to 5, and particularly preferably 2.
As the conductor 8, a gold bump, a solder bump, a conductive paste, a lead copper foil, and a lead wire can be used.

  The prismatic divided composites 9a and 9b have a ratio L / S between the length L of the long side that is the side adjacent to each other and the length S of the short side that is the side adjacent to the other wiring terminal unit. Is in the range of 1 to 100, and the ratio S / T of the short side length S to the total thickness T of the acoustic matching layer side electrode 3, the plate-like piezoelectric body 4, and the wiring side electrode layer 5 is 0.3. It is in the range of -0.7, preferably 0.5-0.7, particularly preferably 0.6. Although there is no restriction | limiting in particular in thickness T, Generally it exists in the range of 0.1-1 mm.

  The prismatic divided composite is connected to each other by a piezoelectric material at the portion where the bottom surface in contact with the acoustic matching layer electrode reaches a portion of 5 to 20% of the thickness of the plate-like piezoelectric material, that is, plate-like It is preferable that the depth of the notch 10 that divides the piezoelectric body 4 and the wiring-side electrode layer 5 is a depth that reaches 80 to 95% of the thickness of the plate-shaped piezoelectric body. The width of the cut 10 is preferably in the range of 0.025 to 0.50 μm.

  The cuts 10 in the prismatic divided composite are preferably filled with a sound-absorbing resin in order to reduce crosstalk between the prismatic divided composites. As the sound absorbing resin, an epoxy resin, a urethane resin, and a silicone resin can be used.

  Each of the first acoustic matching layer 1 and the second acoustic matching layer 2 is provided for each wiring terminal unit by a notch 11 extending from the surface of the second acoustic matching layer 2 to a portion near the surface of the acoustic matching layer side electrode layer 3. It is preferable to be divided corresponding to the complex. It is preferable that the notch 11 of the acoustic matching layer is also filled with a sound absorbing resin. As the sound absorbing resin, an epoxy resin, a urethane resin, and a silicone resin can be used.

  The acoustic matching layer side electrode 3 is a common electrode of the prismatic divided composite. The acoustic matching layer side electrode 3 is larger in size than the first acoustic matching layer 1 in order to facilitate the extraction of electricity to the outside. The part of the wiring side electrode layer 5 that protrudes from the first acoustic matching layer 1 is separated by cutting. Moreover, you may scrape off the area | region which protruded from the 1st acoustic matching layer of the wiring side electrode layer 5 instead of making a notch | incision.

  The wiring-side electrode layer 5 is electrically taken out to the outside by the printed wiring boards 14a and 14b for each composite of each wiring terminal unit. The wiring-side electrode layer 5 and the wiring terminals 12 of the printed wiring boards 14a and 14b are electrically connected via lead wires 15a, 15b and 15c. Of the three wiring terminal unit composites arranged in the direction of the long side of the prismatic divided composite, the wiring terminal unit composites at both ends are electrically connected to each other by lead wires 15a and printed wiring by lead wires 15c. It is electrically connected to the wiring terminal 12 of the board 14b. The central wiring terminal unit complex is electrically connected to the wiring terminals 12 of the printed wiring board 14a by lead wires 15b.

  In the two-dimensional array type ultrasonic probe shown in FIGS. 1 and 2, a printed wiring board is used as a wiring tool. However, the configuration of the wiring tool is not particularly limited, and a normal two-dimensional array type ultrasonic probe is used. The well-known wiring tool currently used for the touch element can be used. Moreover, there is no restriction | limiting in particular also in the connection method of a wiring tool and a wiring side electrode layer, The well-known method used for the normal two-dimensional array type | mold ultrasonic probe can be utilized.

FIG. 3 is a perspective view of another example of a two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention.
In the two-dimensional array type ultrasonic probe of FIG. 3, as a wiring tool, it has an electrode terminal (not shown) at a position corresponding to the complex of each wiring terminal unit on one surface, and on the other surface, A printed wiring board 17 having an electrical wiring 16 electrically connected to each of the electrode terminals is used.

In the two-dimensional array-type ultrasonic probe obtained by the manufacturing method of the present invention, the number of the composites arranged in units of wiring terminals is not particularly limited, but generally 3 to 3 in the direction of the long side of the prismatic divided composite. There are 10 ranges, 5 to 200 ranges in the direction of the short side.

Next, an example of the manufacturing method of the two-dimensional array type ultrasonic probe of the present invention will be described with reference to FIGS.
First, as shown in FIG. 4A, the first acoustic matching is performed on the surface of the electrode layer 20 of the piezoelectric vibrator 23 having a thickness T, which is composed of a plate-like piezoelectric body 22 having electrode layers 20 and 21 on both surfaces. The layer 24 and the second acoustic matching layer 25 are laminated in this order. When the size of the piezoelectric vibrator 23 is larger than that of the first acoustic matching layer 24, the region protruding from the first acoustic matching layer of the electrode layer 21 is separated by cutting or from the first acoustic matching layer of the electrode layer 21. Scrap off the protruding area.

  Next, as shown in FIG. 4B, from the electrode layer 21 side of the piezoelectric vibrator 23, along the length direction (Y direction) and the width direction (X direction) of the piezoelectric vibrator, A plurality of cuts 26 that are divided so that the long side (side in the X direction) is L and the short side (side in the Y direction) is S are close to the surface of the electrode layer (acoustic matching layer side electrode layer) 20. The part is inserted to form a prismatic divided composite 27.

  Next, as shown in FIG. 5, the adjacent prismatic divided composite bodies 27 are electrically connected by the conductors 28 so as to straddle the sides having the length L, and are divided for each wiring terminal. A composite 29 of wiring terminal units composed of the plate-like piezoelectric body and the wiring-side electrode layer is formed.

  Then, each of the wiring-side electrode layers of the composite 29 in units of wiring terminals is connected to each of the electrode terminals of the wiring tool prepared separately. Finally, a sound absorbing material is laminated on the surface of the wiring side electrode layer.

  Another method of manufacturing the two-dimensional array type ultrasonic probe of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 6 (A), a first acoustic matching layer is formed on the surface of the electrode layer 30 of the piezoelectric vibrator 33 having a thickness T, which is composed of a plate-like piezoelectric body 32 having electrode layers 30 and 31 on both surfaces. 34 and the second acoustic matching layer 35 are laminated in this order. When the size of the piezoelectric vibrator 33 is larger than that of the first acoustic matching layer 34, the region protruding from the first acoustic matching layer of the electrode layer 31 is separated by cutting or from the first acoustic matching layer of the electrode layer 31. Scrap off the protruding area.

  Next, as shown in FIG. 6B, from the side of the electrode layer 31 of the piezoelectric vibrator 33, along the length direction (Y direction) and the width direction (X direction) of the piezoelectric vibrator, A plurality of cuts 36 each subdivided so that one length is L and the length of the side adjacent to this side is twice as long as S is formed on the electrode layer (acoustic matching layer side electrode layer) 30. A rectangular prism-shaped composite body 37 is formed up to a portion close to the surface.

  Next, as shown in FIG. 7A, adjacent rectangular prismatic composites 37 are electrically connected by a conductor 38 so as to straddle a side having a length L.

  Next, as shown in FIG. 7B, the rectangular prismatic composite 37 is cut along the side having a length L and divided into lengths S. As a result, the rectangular prismatic composite 37 is divided into prismatic composites 37a and 37b, and a wiring terminal unit composite 40 composed of a plate-like piezoelectric body divided for each wiring unit and a wiring-side electrode layer is formed. The

  Then, each of the wiring side electrode layers of the composite 40 in units of wiring terminals is connected to each of the electrode terminals of the wiring tool prepared separately. Finally, a sound absorbing material is laminated on the surface of the wiring side electrode layer.

  The length of the side of the rectangular prismatic complex 37 adjacent to the side of L is an integer that is three times or more of S, and the adjacent composites are electrically connected so as to straddle the side of L After that, the rectangular prismatic composite may be divided into lengths S along the side having the length L. However, in this case, an electrically independent prismatic split composite is formed, and thus a step of electrically connecting the composites again is required.

It is a perspective view of an example of the two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention. It is the perspective view which looked at the two-dimensional array type ultrasonic probe shown in FIG. 1 from the wiring side electrode layer side. It is a perspective view of another example of the two-dimensional array type ultrasonic probe obtained by the manufacturing method of the present invention. It is a perspective view which shows typically the process until it forms a division | segmentation composite body from a piezoelectric vibrator according to the manufacturing method of the two-dimensional array type ultrasonic probe of this invention. It is a perspective view which shows the process of electrically connecting the division | segmentation composite_body | complex formed in FIG. It is a perspective view which shows typically the process from a piezoelectric vibrator to forming a rectangular prism-shaped composite according to another manufacturing method of the two-dimensional array type ultrasonic probe of the present invention. The perspective view which shows typically the process of forming the composite of the plate-shaped piezoelectric material and wiring side electrode layer which were divided | segmented for every wiring unit from the process of electrically connecting the division | segmentation composite_body | complex formed in FIG. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st acoustic matching layer 2 2nd acoustic matching layer 3 Acoustic matching layer side electrode layer 4 Plate-like piezoelectric material 5 Wiring side electrode layer 6 Composite 6a Wiring terminal unit composite 7 Sound absorbing material 8 Conductor 9a, 9b Square columnar division Composite 10 Notch 11 Notch 12 Wiring terminal 13 Wiring 14a, 14b Printed wiring board 15a, 15b, 15c Lead wire 16 Electrical wiring 17 Printed wiring board 20, 21 Electrode layer 22 Plate-like piezoelectric body 23 Piezoelectric vibrator 24 First acoustic matching Layer 25 second acoustic matching layer 26 notch 27 prismatic divided composite 28 conductor 29 wiring terminal unit composite 30, 31 electrode layer 32 plate-like piezoelectric body 33 piezoelectric vibrator 34 first acoustic matching layer 35 second acoustic matching layer 35 36 cut 37 rectangular divided composite 37a, 37b prismatic divided composite 38 conductor 39 cut 40 wiring terminal unit composite

Claims (4)

A laminated body in which a composite of an acoustic matching layer, an acoustic matching layer side electrode layer, and a plate-like piezoelectric body divided for each wiring terminal unit and a wiring side electrode layer is laminated in this order, including the following steps: A two-dimensional array-type ultrasonic probe including a wiring tool having an electrode terminal electrically connected to each wiring terminal of the wiring-side electrode layer of the laminate, wherein the composite of each wiring terminal unit comprises: A gold bump composed of two or more prismatic divided composites adjacent to each other, wherein the wiring side electrode layer of each wiring terminal unit is prepared separately for each of the prismatic divided composites. , Solder bumps, conductive paste, lead copper foil, and lead wires are electrically connected with a conductor selected from the group consisting of lead wires, and the prismatic divided composite is formed on the sides adjacent to each other. Adjacent to the length L of a certain long side and other wiring terminal units The ratio L / S to the short side length S which is the side of the first side is in the range of 1 to 100, and the short side length S, the acoustic matching layer side electrode, the plate-like piezoelectric body, and the wiring side electrode layer The method of manufacturing a two-dimensional array type ultrasonic probe in which the ratio S / T to the total thickness T is in the range of 0.3 to 0.7:
(1) A step of laminating an acoustic matching layer on the surface of one electrode layer of a piezoelectric vibrator having a thickness T made of a plate-like piezoelectric body having electrode layers on both surfaces;
(2) From the other electrode layer side of the piezoelectric vibrator, the length of the long side of the upper surface is L and the length of the short side is S along the length direction and width direction of the piezoelectric vibrator. A step of forming a prismatic divided composite by inserting a plurality of cuts each subdivided so as to be close to the surface of the other electrode layer;
(3) A conductor selected from the group consisting of a gold bump, a solder bump, a conductive paste, a lead copper foil, and a lead wire, in which adjacent divided composites are separately prepared so as to straddle the side having the length L. Electrically connecting and forming a composite of a plate-like piezoelectric body divided for each wiring terminal and the wiring-side electrode layer; and
(4) A step of connecting each of the wiring-side electrode layers of the composite to each of the electrode terminals of the wiring tool prepared separately. 2. The method for manufacturing a two-dimensional array type ultrasonic probe according to claim 1, wherein the conductor used in the step (3) is a gold bump, a solder bump, or a lead wire . A laminated body in which a composite of an acoustic matching layer, an acoustic matching layer side electrode layer, and a plate-like piezoelectric body divided for each wiring terminal unit and a wiring side electrode layer is laminated in this order, including the following steps: A two-dimensional array-type ultrasonic probe including a wiring tool having an electrode terminal electrically connected to each wiring terminal of the wiring-side electrode layer of the laminate, wherein the composite of each wiring terminal unit comprises: A gold bump composed of two or more prismatic divided composites adjacent to each other, wherein the wiring side electrode layer of each wiring terminal unit is prepared separately for each of the prismatic divided composites. , Solder bumps, conductive paste, lead copper foil, and lead wires are electrically connected with a conductor selected from the group consisting of lead wires, and the prismatic divided composite is formed on the sides adjacent to each other. Adjacent to the length L of a certain long side and other wiring terminal units The ratio L / S to the short side length S which is the side of the first side is in the range of 1 to 100, and the short side length S, the acoustic matching layer side electrode, the plate-like piezoelectric body, and the wiring side electrode layer The method of manufacturing a two-dimensional array type ultrasonic probe in which the ratio S / T to the total thickness T is in the range of 0.3 to 0.7:
(1) A step of laminating an acoustic matching layer on the surface of one electrode layer of a piezoelectric vibrator having a thickness T made of a plate-like piezoelectric body having electrode layers on both surfaces;
(2) From the other electrode layer side of the piezoelectric vibrator, the length of one side of the upper surface is L along the length direction and width direction of the piezoelectric vibrator, and the length of the side adjacent to this side A step of forming a rectangular prism-shaped composite by inserting a plurality of cuts that are subdivided so as to be an integral multiple of S up to a portion close to the surface of the other electrode layer;
(3) An electrically conductive material selected from the group consisting of gold bumps, solder bumps, conductive paste, lead copper foil, and lead wires, in which adjacent composites are separately prepared so as to straddle the side having the length L. Connecting to:
(4) A rectangular prismatic composite is divided into length S along a side having a length of L, and a composite of a plate-like piezoelectric body and a wiring-side electrode layer divided for each wiring unit is obtained. Forming; and
(5) A step of connecting each of the wiring-side electrode layers of the composite to each of the electrode terminals of the wiring tool prepared separately. The method for manufacturing a two-dimensional array type ultrasonic probe according to claim 3, wherein the conductor used in the step (3) is a gold bump, a solder bump, or a lead wire.

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