JP5065085B2 - Ultrasonic probe and manufacturing method thereof - Google Patents

Description

  The present invention relates to an ultrasonic probe, and more particularly to a small-sized ultrasonic probe suitable for loading into a catheter and a method for manufacturing the same.

  The ultrasonic probe is used as an ultrasonic transmitter / receiver of a medical ultrasonic diagnostic apparatus. Recently, an ultrasonic probe is loaded on a catheter and an ultrasonic diagnosis is performed with the catheter inserted into the body. In this ultrasonic probe for loading a catheter, there is a high demand for miniaturization in order to reduce the burden on the patient and enhance the insertion into a smaller body cavity such as a deep blood vessel.

  An ultrasonic probe generally includes a thin piezoelectric ceramic sheet whose upper and lower surfaces are flat and a pair of electrode layers formed to face the upper and lower surfaces of the piezoelectric ceramic sheet. An acoustic matching layer for increasing the propagation efficiency of ultrasonic waves to the subject is attached to the electrode layer on the ultrasonic probe side that transmits and receives ultrasonic waves, and is opposite to the side that transmits and receives ultrasonic waves. The electrode layer is provided with a sound absorbing layer for absorbing ultrasonic waves that become noise. Since the acoustic matching layer and the sound absorbing layer are usually formed of a non-conductive polymer material, the electrode layers formed on the upper and lower surfaces of the piezoelectric ceramic sheet are externally connected with the downsizing of the ultrasonic probe. It tends to be difficult to connect to a power source.

  As a method of facilitating connection of the ultrasonic probe to an external power source, one of the electrode layers formed on the upper and lower surfaces of the piezoelectric ceramic sheet is extended to the opposite surface, and the upper and lower electrode layers are moved up and down. There is known a method for enabling connection to an external power source from either one direction. In general, an electrode layer obtained by extending the upper and lower electrode layers to the opposite surface is called a folded electrode layer.

  Patent Document 1 discloses an ultrasonic probe having a folded electrode layer that extends to the lower surface of a piezoelectric ceramic sheet by forming a conductive layer on the side surface of the piezoelectric ceramic sheet. .

Patent Document 2 discloses an ultrasonic probe formed on a folded electrode layer on the surface of an insulating material disposed around the width direction of a piezoelectric ceramic sheet.
JP-A-8-280095 JP 2001-292495 A

As described above, it is useful to form the folded electrode layer in order to facilitate the connection between the electrode layer of the ultrasonic probe and the lead wire. However, with the miniaturization of the ultrasonic probe, it becomes difficult to form the folded electrode layer. Particularly recently, an extremely small ultrasonic probe for incorporation into a blood vessel catheter having a diameter of 1 mm or less has been desired. In such a small ultrasonic probe, a folded electrode layer is desired. Is difficult to form industrially.
Accordingly, an object of the present invention is to provide a technique for industrially advantageously producing a small-sized ultrasonic probe having a folded electrode layer particularly suitable for loading a catheter.

The present invention is an ultrasonic probe manufacturing method including the following steps (1) to (7).
(1) A step of preparing a piezoelectric ceramic sheet having a large number of small-diameter through holes arranged in alignment along the sheet plane.
(2) A step of forming a lower electrode layer in contact with the lower surface opening of each small diameter through hole on the lower surface of the piezoelectric ceramic sheet, and attaching a conductive layer to the inner wall surface of each small diameter through hole.
(3) On the upper surface of the piezoelectric ceramic sheet, a lower electrode layer terminal electrode layer is disposed around the upper surface opening of each small-diameter through hole, and faces the lower electrode layer, and the lower electrode layer terminal The upper electrode layer is electrically connected to the upper electrode layer at a position not in electrical contact with the electrode layer, and the lower electrode layer terminal electrode layer and the upper electrode layer disposed in the width direction of the upper electrode layer Forming a terminal electrode layer for an electrode layer, and further attaching a conductive layer to the inner wall surface of each small-diameter through hole;
(4) A step of providing an acoustic matching layer on the surface of the upper electrode layer.
(5) A step of providing a sound absorbing layer on the surface of the lower electrode layer.
(6) With respect to the piezoelectric ceramic sheet that has undergone at least the steps (2) and (3), the small diameter through hole, the lower electrode layer electrically connected to the conductive layer of the small diameter through hole, and the lower electrode layer A terminal electrode layer for the side electrode layer, and an upper electrode layer facing the lower electrode layer are included in one section, and the terminal electrode layer for the upper electrode layer, the terminal electrode layer for the lower electrode layer, Cutting along the one side so that the small-diameter through hole is arranged at a position eccentric from the center of the one side.
(7) A step of connecting a lead wire to each of the upper electrode layer terminal electrode layer and the lower electrode layer terminal electrode layer.
However, the order of the step (2) and the step (3) may be reversed, and the order of the steps (4) to (6) is arbitrary.

  The present invention also provides a rectangular piezoelectric ceramic sheet piece having a through hole extending in the thickness direction in the vicinity of the side surface, an upper electrode layer provided on the upper surface of the piezoelectric ceramic sheet piece, and an upper side electrically connected to the upper electrode layer Terminal electrode layer for electrode layer, lower electrode layer provided on the lower surface of the piezoelectric ceramic sheet piece, conductive layer provided on the inner wall surface of the through hole electrically connected to the lower electrode layer, the conductive layer A lower electrode layer terminal electrode layer provided on the upper surface of the piezoelectric ceramic sheet piece electrically connected to the upper electrode layer terminal electrode layer and the lower electrode layer terminal electrode layer. There is also an ultrasonic probe including a wire, an acoustic matching layer provided on the upper surface of the upper electrode layer, and a sound absorbing layer provided on the lower surface of the lower electrode layer. In the ultrasonic probe of the present invention, the through hole is provided in the vicinity of any side surface of the piezoelectric ceramic sheet piece and at a position off the center of the side surface, and the terminal electrode for the upper electrode layer It is preferable that the layer and the terminal electrode layer for the lower electrode layer are provided side by side with the center of the side surface as a boundary.

By using the manufacturing method of the present invention, a plurality of small ultrasonic probes having folded electrode layers can be manufactured from one piezoelectric ceramic sheet.
The small ultrasonic probe manufactured using the manufacturing method of the present invention can be advantageously used for loading a catheter. In addition, since the terminal electrode layers for both electrode layers are formed side by side on one surface (upper surface), it is easy to attach a signal line, and an ultrasonic probe suitable for downsizing can be obtained.

  The ultrasonic probe of the present invention and the manufacturing method thereof will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view of an example of an ultrasonic probe according to the present invention.
In FIG. 1, an ultrasonic probe includes a rectangular piezoelectric ceramic sheet piece 2 having a through hole 1 extending in the thickness direction in the vicinity of a side surface, an upper electrode layer 3 and an upper electrode provided on the upper surface of the piezoelectric ceramic sheet piece 2. The upper electrode layer terminal electrode layer 4 electrically connected to the layer 3, the lower electrode layer 5 provided on the lower surface of the piezoelectric ceramic sheet piece 2, and the through hole 1 electrically connected to the lower electrode layer 5. The conductive layer 6 provided on the inner wall surface, the lower electrode layer terminal electrode layer 7 provided on the upper surface of the piezoelectric ceramic sheet piece 2 electrically connected to the conductive layer 6, the upper electrode layer terminal electrode layer 4 and the lower layer The upper electrode layer lead wire 9 a and the lower electrode layer lead wire 9 b connected to each of the terminal electrode layers 7 for the side electrode layer by the bonding material layer 8, and the acoustic matching layer 10 provided on the upper surface of the upper electrode layer 3. , And sound absorption provided on the lower surface of the lower electrode layer 5 Consisting of 11.

  In the ultrasonic probe of the present invention, the folded electrode layer is formed by extending the lower electrode layer 5 on the upper surface of the piezoelectric ceramic sheet piece 2 by the conductive layer 6 and the terminal electrode layer 7 for the lower electrode layer.

  The through-hole 1 formed in the piezoelectric ceramic sheet piece 2 is preferably circular when viewed from above in order to facilitate manufacturing, but may be rectangular. The through hole 1 is preferably formed at a position deviated from the center of the lower electrode layer terminal electrode layer 7 in order to expand the connection region of the lower electrode layer terminal electrode layer 7 with the lead wire 9b. In the present embodiment, the terminal electrode layer 7 for the lower electrode layer is formed in a rectangular shape, and the through hole 1 is provided in the vicinity of one side of the rectangular shape and at an eccentric position from the center of this side. ing.

  Examples of the material of the piezoelectric ceramic sheet piece 2 include piezoelectric ceramic materials such as lead zirconate titanate (PZT) and lithium niobate.

  The upper electrode layer 3 becomes an ultrasonic wave transmission / reception surface. The ratio (W: L) between the width W and the length L of the upper electrode layer 3 is preferably in the range of 0.8: 1.0 to 1.0: 0.8.

  The lower electrode layer 5 is formed at a position facing the upper electrode layer 3. The lower electrode layer 5 is preferably formed on the entire lower surface of the piezoelectric ceramic sheet piece 2.

  The upper electrode layer terminal electrode layer 4 and the lower electrode layer terminal electrode layer 7 are adjacent to the lower electrode layer terminal electrode layer 7 on the side surface side of the piezoelectric ceramic sheet piece 2 having the through holes 1. It is preferable that the side surface of the side surface be disposed side by side. As a result, the two terminal electrode layers 4 and 7 are provided side by side in the width W direction of the upper electrode layer 3.

  Examples of the conductive material forming the upper electrode layer 3, the upper electrode layer terminal electrode layer 4, the lower electrode layer 5, the conductive layer 6 and the lower electrode layer terminal electrode layer 7 include silver, chromium, copper, Mention may be made of metals such as nickel and gold, and laminates of these metals.

  Examples of the material of the bonding material layer 8 for fixing the upper electrode layer lead wire 9a and the lower electrode layer lead wire 9b to the electrode layers 4 and 7 include solder and a conductive adhesive. it can. The lead wires 9a and 9b may be fixed to the electrode layers 4 and 7 by welding. Further, the lead wires 9a and 9b may be formed by wire bonding.

  Examples of the material of the acoustic matching layer 10 include a resin material such as an epoxy resin. The acoustic matching layer 10 may be two or more layers.

  Examples of the material of the sound absorbing layer 11 include rubber and an epoxy resin in which metal powder such as tungsten powder is dispersed.

The ultrasonic probe of the present invention can be manufactured by a method including the following steps (1) to (7).
(1) A step of preparing a piezoelectric ceramic sheet having a large number of small-diameter through holes arranged in alignment along the sheet plane.
(2) A step of forming a lower electrode layer in contact with the lower surface opening of each small diameter through hole on the lower surface of the piezoelectric ceramic sheet, and attaching a conductive layer to the inner wall surface of each small diameter through hole.
(3) On the upper surface of the piezoelectric ceramic sheet, a lower electrode layer terminal electrode layer is disposed around the upper surface opening of each small-diameter through hole, and faces the lower electrode layer, and the lower electrode layer terminal The upper electrode layer is electrically connected to the upper electrode layer at a position not in electrical contact with the electrode layer, and the lower electrode layer terminal electrode layer and the upper electrode layer disposed in the width direction of the upper electrode layer Forming a terminal electrode layer for an electrode layer, and further attaching a conductive layer to the inner wall surface of each small-diameter through hole;
(4) A step of providing an acoustic matching layer on the surface of the upper electrode layer.
(5) A step of providing a sound absorbing layer on the surface of the lower electrode layer.
(6) With respect to the piezoelectric ceramic sheet that has undergone at least the steps (2) and (3), the small diameter through hole, the lower electrode layer electrically connected to the conductive layer of the small diameter through hole, and the lower electrode layer A terminal electrode layer for the side electrode layer, and an upper electrode layer facing the lower electrode layer are included in one section, and the terminal electrode layer for the upper electrode layer, the terminal electrode layer for the lower electrode layer, Cutting along the one side so that the small-diameter through hole is arranged at a position eccentric from the center of the one side.
(7) A step of connecting a lead wire to each of the upper electrode layer terminal electrode layer and the lower electrode layer terminal electrode layer.

  The manufacturing method of said ultrasonic probe is demonstrated with reference to FIGS. 2-8 of an accompanying drawing.

  FIG. 2 is a plan view of an example of the piezoelectric ceramic sheet 22 having the small diameter through hole 21 prepared in the step (1). In FIG. 2, the piezoelectric ceramic sheet 22 is a circular sheet in which four small-diameter through holes 21 are arranged in the vertical and horizontal directions along the sheet plane. One ultrasonic probe can be manufactured for one small diameter through hole 21. The number of small-diameter through holes 21 per piezoelectric ceramic sheet 22 is not particularly limited, but is preferably in the range of 2 to 1000, particularly preferably in the range of 10 to 500.

  The thickness of the piezoelectric ceramic sheet 22 is preferably in the range of 0.010 to 0.20 mm, particularly preferably in the range of 0.020 to 0.10 mm. The inner diameter of the small-diameter through hole 21 is preferably in the range of 0.010 to 0.40 mm, particularly preferably in the range of 0.020 to 0.20 mm. The aspect ratio of the small diameter through hole 21 (= thickness of the piezoelectric ceramic sheet 22 / inner diameter of the small diameter through hole 21) is preferably in the range of 0.1 to 1.0, particularly preferably in the range of 0.2 to 0.8. It is.

  The piezoelectric ceramic sheet 22 having the small-diameter through-hole 21 is formed by, for example, a method of forming a small-diameter through-hole at a predetermined position by perforating a thin-walled piezoelectric ceramic sheet previously formed to a desired thickness, or thicker than a desired thickness. The piezoelectric ceramic plate can be manufactured by forming a small-diameter through hole at a predetermined position by drilling, and then polishing each of the upper and lower surfaces of the piezoelectric ceramic plate. A method of polishing after the latter drilling is preferred.

  FIG. 3 is a partially enlarged rear view of an example of the piezoelectric ceramic sheet after the lower electrode layer 23 and the conductive layer 24 are attached to the lower surface of the piezoelectric ceramic sheet 22 in accordance with the step (2). In FIG. 3, one lower electrode layer 23 is formed corresponding to each through-hole 21, but the lower electrode layer 23 may be formed in a stripe shape extending in the vertical or horizontal direction, It may be formed on the entire lower surface of the piezoelectric ceramic sheet 22.

  FIG. 4 shows a state after the conductive layer 24, the lower electrode layer terminal electrode layer 25, the upper electrode layer 26, and the upper electrode layer terminal electrode layer 27 are provided on the upper surface of the piezoelectric ceramic sheet 22 in accordance with the step (3). FIG. 5 is a partial enlarged plan view of an example of a piezoelectric ceramic sheet, and FIG. 5 is a cross-sectional view taken along the line II of FIG.

  In the present invention, the lower electrode layer 23 and the conductive layer 24 are provided in the step (2), and the conductive layer 24 and the terminal electrode layer 25 for the lower electrode layer are provided in the step (3). Thus, the lower electrode layer 23, the conductive layer 24, and the lower electrode layer terminal electrode layer 25 are integrally formed with high conductivity. Further, in the step (3), the upper electrode layer 26 and the upper electrode layer terminal electrode layer 27 are additionally provided so that the upper electrode layer 26 and the upper electrode layer terminal electrode layer 27 have high conductivity integrally. Formed with. Note that the order of the steps (2) and (3) may be reversed. Thus, since the conductive layer 24 is formed twice in the step (2) and the step (3), there is a possibility that the conductor is insufficiently formed only from one surface. This can be prevented.

  Each electrode layer and conductive layer can be formed by, for example, an ion plating method using a mask material, an evaporation method, or a sputtering method.

  6 is a partially enlarged plan view of an example of the piezoelectric ceramic sheet after the acoustic matching layer 28 is formed on the piezoelectric ceramic sheet 22 of FIG. 4 according to the step (4). In FIG. 6, the acoustic matching layers 28 are formed in stripes extending laterally on the surfaces of the plurality of upper electrode layers 26, but one acoustic matching layer 28 is provided corresponding to each upper electrode layer 26. You may form, and you may form in the whole upper surface of the piezoelectric ceramic sheet | seat 22 except the part in which the terminal electrode layer 27 for upper electrode layers and the terminal electrode layer 25 for lower electrode layers are formed.

  The acoustic matching layer 28 can be formed by a method in which an acoustic matching layer forming resin sheet is bonded, or a method in which a liquid acoustic matching layer forming resin material is applied and cured.

  FIG. 7 is a partially enlarged rear view of an example of the piezoelectric ceramic sheet after the sound absorbing layer 29 is formed on the piezoelectric ceramic sheet 22 of FIG. 6 according to the step (5). In FIG. 7, the sound absorbing layer 29 is formed in a stripe shape extending laterally on the surface of the plurality of lower electrode layers 23, but one sound absorbing layer 29 is formed corresponding to each lower electrode layer 23. Alternatively, it may be formed on the entire lower surface of the piezoelectric ceramic sheet 22.

  The sound absorbing layer 29 can be formed by a method of bonding a sound absorbing layer forming sheet or a method of applying and curing a liquid sound absorbing layer forming material.

  When the terminal electrode layer for the upper electrode layer and the terminal electrode layer for the lower electrode layer and the lead wire are connected by a bonding material, the acoustic matching layer 28 is formed [step (4)], and then the piezoelectric ceramic sheet is cut. Prior to the step (6), it is preferable to form a bonding material layer on each of the upper electrode layer terminal electrode layer and the lower electrode layer terminal electrode layer.

  FIG. 8 is a partially enlarged plan view of an example of the piezoelectric ceramic sheet after the bonding material layer 30 is formed on each of the upper electrode layer terminal electrode layer 27 and the lower electrode layer terminal electrode layer 25. The bonding material layer 30 may be formed before the sound absorbing layer is formed [step (5)].

  FIG. 9 is a partially enlarged plan view of an example of a piezoelectric ceramic sheet showing a cutting line 31 when cutting the piezoelectric ceramic sheet 22 in accordance with the step (6). In the present invention, the small-diameter through hole, the lower electrode layer electrically connected to the conductive layer of the small-diameter through hole, the terminal electrode layer for the lower electrode layer, and the lower electrode layer facing each other according to the cutting line 31 The upper electrode layer is cut so as to be included in one section.

  Then, in the step (7), the lead electrode layer for the upper electrode layer and the terminal electrode layer for the lower electrode layer of the piezoelectric ceramic sheet piece obtained by the step (6) are respectively led through the bonding material layer. By connecting the lines, the ultrasonic probe shown in FIG. 1 can be manufactured.

  The order of the steps (4) to (6) can be arbitrarily determined. For example, the formation of the acoustic matching layer and the formation of the sound absorbing layer may be reversed [in the order of steps (5), (4), (6)], the acoustic matching layer is formed, and then the piezoelectric ceramic sheet is formed. After cutting, a sound absorbing layer may be formed [in the order of steps (4), (6), (5)], and after cutting the piezoelectric ceramic sheet, an acoustic matching layer and a sound absorbing layer are formed. [Order of steps (6), (4), (5)].

It is a perspective view of an example of an ultrasonic probe according to the present invention. It is a top view of an example of the piezoelectric ceramic sheet | seat which has a small diameter through-hole used in the manufacturing method of the ultrasonic probe of this invention. FIG. 3 is an enlarged rear view of an example of a piezoelectric ceramic sheet after a lower electrode layer and a conductive layer on the inner wall surface of a through hole are formed on the piezoelectric ceramic sheet of FIG. 2. The enlarged plan view of an example of the piezoelectric ceramic sheet after forming the upper electrode layer, the terminal electrode layer for the upper electrode layer, the terminal electrode layer for the lower electrode layer, and the conductive layer on the inner wall surface of the through hole on the piezoelectric ceramic sheet of FIG. It is. It is the II sectional view taken on the line of FIG. FIG. 5 is an enlarged plan view of an example of a piezoelectric ceramic sheet after an acoustic matching layer is formed on the piezoelectric ceramic sheet of FIG. 4. FIG. 7 is an enlarged rear view of an example of a piezoelectric ceramic sheet after a sound absorbing layer is formed on the piezoelectric ceramic sheet of FIG. 6. FIG. 8 is an enlarged plan view of an example of a piezoelectric ceramic sheet after a bonding material layer is formed on each of an upper electrode layer terminal electrode layer and a lower electrode layer terminal electrode layer of the piezoelectric ceramic sheet of FIG. 7. It is an enlarged plan view of an example of a piezoelectric ceramic sheet for explaining cutting lines of the piezoelectric ceramic sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Through-hole 2 Piezoelectric ceramic sheet piece 3 Upper electrode layer 4 Terminal electrode layer for upper electrode layers 5 Lower electrode layer 6 Conductive layer 7 Terminal electrode layer for lower electrode layers 8 Bonding material layer 9a Lead wire for upper electrode layers 9b Lower Side electrode layer lead wire 10 Acoustic matching layer 11 Sound absorbing layer 21 Small diameter through hole 22 Piezoelectric ceramic sheet 23 Lower electrode layer 24 Conductive layer 25 Lower electrode layer terminal electrode layer 26 Upper electrode layer 27 Upper electrode layer terminal electrode layer 28 acoustic matching layer 29 sound absorbing layer 30 bonding material layer 31 cutting line

Claims (3)

An ultrasonic probe manufacturing method including the following steps:
(1) A step of preparing a piezoelectric ceramic sheet having a large number of small-diameter through holes arranged in alignment along the sheet plane;
(2) forming a lower electrode layer in contact with the lower surface opening of each small-diameter through-hole on the lower surface of the piezoelectric ceramic sheet, and attaching a conductive layer to the inner wall surface of each small-diameter through-hole;
(3) On the upper surface of the piezoelectric ceramic sheet, a lower electrode layer terminal electrode layer is disposed around the upper surface opening of each small-diameter through hole, and faces the lower electrode layer, and the lower electrode layer terminal The upper electrode layer is electrically connected to the upper electrode layer at a position not in electrical contact with the electrode layer, and the lower electrode layer terminal electrode layer and the upper electrode layer disposed in the width direction of the upper electrode layer Forming a terminal electrode layer for an electrode layer and further attaching a conductive layer to the inner wall surface of each small-diameter through hole;
(4) attaching an acoustic matching layer to the surface of the upper electrode layer;
(5) A step of providing a sound absorbing layer on the surface of the lower electrode layer;
(6) With respect to the piezoelectric ceramic sheet that has undergone at least the steps (2) and (3), the small diameter through hole, the lower electrode layer electrically connected to the conductive layer of the small diameter through hole, and the lower electrode layer A terminal electrode layer for the side electrode layer, and an upper electrode layer facing the lower electrode layer are included in one section, and the terminal electrode layer for the upper electrode layer, the terminal electrode layer for the lower electrode layer, Cutting along the side so that the small-diameter through hole is arranged at a position eccentric from the center of the side;
(7) connecting the lead wires to the terminal electrode layer for the upper electrode layer and the terminal electrode layer for the lower electrode layer;
However, the order of the step (2) and the step (3) may be reversed, and the order of the steps (4) to (6) is arbitrary.   Rectangular piezoelectric ceramic sheet piece having through holes extending in the thickness direction in the vicinity of the side surface, upper electrode layer provided on the upper surface of the piezoelectric ceramic sheet piece, and terminal electrode for the upper electrode layer electrically connected to the upper electrode layer Layer, a lower electrode layer provided on the lower surface of the piezoelectric ceramic sheet piece, a conductive layer provided on the inner wall surface of the through-hole electrically connected to the lower electrode layer, and electrically connected to the conductive layer A lower electrode layer terminal electrode layer provided on the upper surface of the piezoelectric ceramic sheet piece, a lead wire attached to each of the upper electrode layer terminal electrode layer and the lower electrode layer terminal electrode layer, and the upper electrode An ultrasonic probe comprising: an acoustic matching layer provided on an upper surface of the layer; and a sound absorbing layer provided on a lower surface of the lower electrode layer.   The through hole is provided in the vicinity of any side surface of the piezoelectric ceramic sheet piece and at a position off the center of the side surface, and the terminal electrode layer for the upper electrode layer and the terminal electrode for the lower electrode layer The ultrasonic probe according to claim 2, wherein the layer is provided side by side with the center of the side surface as a boundary.

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