JP5457843B2 - Ultrasonic probe - Google Patents

Description

  The present invention relates to an ultrasonic probe that is connected to an ultrasonic diagnostic apparatus and transmits / receives ultrasonic waves to / from a subject, and more particularly to an electrode structure of a piezoelectric element.

  There is an ultrasonic diagnostic apparatus that scans an inside of a subject with ultrasonic waves and images an internal state of the subject based on a reception signal generated from a reflected wave from the inside of the subject. Such an ultrasonic diagnostic apparatus transmits an ultrasonic wave from an ultrasonic probe into a subject, receives a reflected wave caused by an acoustic impedance mismatch inside the subject, and generates a reception signal.

  The ultrasonic probe is provided with a plurality of piezoelectric elements in the scanning direction that generate an ultrasonic wave by vibrating based on a transmission signal and generate a reception signal by receiving a reflected wave.

  Since it is necessary to apply a voltage to the ultrasonic wave transmitting surface from the back surface of the piezoelectric element, a signal electrode is provided on the back surface of the piezoelectric element, and a ground electrode is provided on the ultrasonic wave transmitting surface of the piezoelectric element. A flexible printed circuit board is used as a wiring member for connecting the signal electrode and the ground electrode and an electric circuit for transmitting / receiving an electrical signal to / from the ultrasonic diagnostic apparatus.

  There are two main types of configurations for drawing electrodes from piezoelectric elements: a configuration in which a flexible printed circuit board is soldered to the side surface of the piezoelectric element, and a configuration in which a flexible printed circuit board is soldered or adhesively bonded to the back surface of the piezoelectric element. Is done. For example, Patent Document 1 discloses an example in which a flexible printed circuit board is bonded and bonded on the back surface of a piezoelectric element.

  The configuration in which the flexible printed circuit board is soldered to the side surface of the piezoelectric element is used, for example, when the piezoelectric element is a circular vibrator. FIG. 12 is an example of a configuration of a piezoelectric element, a backing material, and a flexible printed board in a conventional ultrasonic probe in which a flexible printed board is soldered to the side surface of the piezoelectric element.

  In the example of FIG. 12, the piezoelectric element 10, the signal electrode 11 formed so as to cover substantially the entire back surface and one side surface of the piezoelectric element 10, the substantially entire ultrasonic wave transmission surface of the piezoelectric element 10, and the other side surface. A ground electrode 12 formed so as to cover the back surface, a backing material 3 bonded to the back surface of the piezoelectric element 10, a flexible printed circuit board 2 that extracts the signal electrode 11, and a flexible printed circuit board 5 that extracts the ground electrode 12. The

  As shown in FIG. 12, the signal electrode connection portion 101 of the signal electrode 11 located on the side surface of the piezoelectric element 10 and the signal wiring layer 22 of the flexible printed circuit board 2 are electrically connected. Further, the ground electrode connecting portion 121 of the ground electrode 12 located on the side surface of the piezoelectric element 10 and the ground wiring layer 52 of the flexible printed circuit board 5 are electrically connected.

  A signal electrode notch 112 is provided at the end of the signal electrode 11 opposite to the signal electrode connection portion 101, and a ground electrode is provided at the end of the ground electrode 12 opposite to the ground electrode connection portion 121. A notch 122 is provided. The signal electrode 11 and the ground electrode 12 are electrically separated by the signal electrode notch 112 and the ground electrode notch 122.

  The configuration in which the flexible printed board is soldered or adhesively bonded to the back surface of the piezoelectric element is used, for example, when the piezoelectric element is a rectangular vibrator. FIGS. 13 and 14 are examples of a piezoelectric element, a backing material, and a flexible printed board in a conventional ultrasonic probe in which a flexible printed board is soldered or adhesively bonded to the back surface of the piezoelectric element.

  For example, FIG. 14 is an example of the ultrasonic probe disclosed in Patent Document 1, in which the piezoelectric element 10, the signal electrode 11 formed so as to cover the central portion of the back surface of the piezoelectric element 10, and the superposition of the piezoelectric element 10 are illustrated. A grounding electrode 12 that covers almost the entire surface of the acoustic wave transmission surface and is drawn out to the back surface of the piezoelectric element 10 through the side surface of the piezoelectric element 10, a backing material 3 joined to the back surface of the piezoelectric element 10, and a piezoelectric element 10 and the backing material 3, and the flexible printed circuit board 2 that draws out the signal electrode 11 and the ground electrode 12.

  As shown in FIG. 14, the flexible printed circuit board 2 includes a first insulating layer 27, a ground wiring layer 26, a second insulating layer 25, a signal wiring layer 22, and a base layer (third insulating layer). 21, and a second protective layer (spacer) 24.

  The central portions of the signal wiring layer 22 and the base layer 21 are pushed up by the second protective layer 24, so that the electrode connection portion 221 and the ground wiring layer 26 of the signal wiring layer 22 have substantially the same height, and the back surface of the piezoelectric element 10. Join with. At this time, the signal electrode 11 and the electrode connection part 221 are electrically connected. In addition, the ground electrode connecting portion 121 drawn to the back surface of the piezoelectric element 10 of the ground electrode 12 and the ground wiring layer 26 are electrically connected.

  In the case of a configuration in which the flexible printed circuit board 2 is soldered or adhesively bonded to the back surface of the piezoelectric element 10 as in the example of FIG. 13 or FIG. 14, the flexible printed circuit board 2 is attached after the piezoelectric element 10 and the flexible printed circuit board 2 are bonded. In general, the piezoelectric element 10 is bent at a substantially right angle along the backing material 3 at the end of the piezoelectric element 10.

JP 2007-167445 A

  On the other hand, as shown in FIG. 12, the configuration in which the flexible printed boards 2 and 5 are soldered to the side surface of the piezoelectric element 10 is soldered on the side surface of the thin piezoelectric element 10, and thus an effective solder area cannot be secured. There is a problem that the yield is not stable because the connection quality of the electrodes deteriorates and the work becomes complicated.

  13 and 14, when the flexible printed circuit board 2 is soldered or adhesively bonded to the back surface of the piezoelectric element 10, the flexible printed circuit board 2 is attached to the piezoelectric element 10 in order to reduce the size of the ultrasonic probe. Therefore, it is difficult to use a piezoelectric vibrator other than a rectangle. Further, there is a high possibility that the signal wiring layer 22 is disconnected at the bent portion, and it is necessary to provide a protective layer for protection.

  Furthermore, as shown in Patent Document 1 (FIG. 14), in the case of a configuration in which the ground electrode 12 is pulled out to the back surface through the side surface of the piezoelectric element 10, the effective portion of the piezoelectric element 10 is limited to a portion covered with the signal electrode 11. Ineffective portions are formed. Since this invalid portion does not contribute to transmission / reception of ultrasonic waves, an attempt to increase the effective portion leads to an unnecessary increase in the size of the ultrasonic probe.

  The present invention solves the above-mentioned problem, and in addition to the case where a rectangular vibrator is used, when a piezoelectric vibrator other than a rectangle (for example, an octagonal piezoelectric vibrator) is used, the back surface of the piezoelectric element is flexible. An object of the present invention is to provide an ultrasonic probe in which a bent portion is protected by a protective layer by a configuration in which a printed board is soldered or adhesively bonded.

  It is another object of the present invention to provide an ultrasonic probe that does not require an ineffective portion in a piezoelectric element by soldering or adhesively bonding a flexible printed circuit board to the back surface of the piezoelectric element.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a piezoelectric vibration component including one or more piezoelectric elements each having a ground electrode disposed on an ultrasonic wave transmission surface and a signal electrode disposed on a back surface; An ultrasonic probe comprising a backing material overlaid on a back surface of the piezoelectric vibration component, and a flexible printed circuit board interposed between the piezoelectric vibration component and the backing material, wherein the flexible printed circuit board is partially A base layer having a raised portion, a signal wiring layer formed along the base layer on the surface of the base layer on the piezoelectric vibration component side, and a portion corresponding to the raised portion connected to the signal electrode, A protective layer that is formed on both sides of a part of the signal wiring layer corresponding to the raised part and protects the signal wiring layer corresponding to a part other than the raised part, A portion of the signal wiring layer corresponding to the raised portion is connected to the surface of the piezoelectric vibration component side and the back surface of the signal electrode, the surface of the protective layer on the piezoelectric vibration component side, and the signal electrode An ultrasonic probe characterized in that the back surface is connected.

  According to the present invention, in addition to the case where a rectangular vibrator is used, in the case where a piezoelectric vibrator other than a rectangle (for example, an octagonal piezoelectric vibrator) is used, the flexible printed circuit board is soldered or bonded to the back surface of the piezoelectric element. By the structure to join, the ultrasonic probe which protected the bending part with the protective layer can be provided.

  In addition, it is possible to install a signal electrode that applies a voltage to the piezoelectric element so as to cover almost the entire back surface of the piezoelectric element, so that an ineffective portion is not required and the ultrasonic probe can be miniaturized. It becomes.

It is an exploded view of the piezoelectric element, backing material, and flexible printed circuit board in 1st Embodiment. It is a top view of the flexible printed circuit board in a 1st embodiment. It is an expanded sectional view of the flexible printed circuit board in a 1st embodiment. It is a figure for demonstrating the production method of the flexible printed circuit board in 1st Embodiment. It is a figure for demonstrating the production method of the flexible printed circuit board in 1st Embodiment. 1 is a schematic view of an ultrasonic probe according to the present invention. It is a figure for demonstrating the production method of the flexible printed circuit board in the modification 1. FIG. It is a figure for demonstrating the production method of the flexible printed circuit board in the modification 1. FIG. 10 is a plan view of a flexible printed circuit board in Modification 1. FIG. 10 is an exploded view of a piezoelectric element, a backing material, and a flexible printed board in Modification 1. FIG. It is a top view of a flexible printed circuit board in the case of using a piezoelectric element in which a circular part is cut out linearly. It is sectional drawing which shows an example of the conventional ultrasonic probe which connects both a signal electrode and a ground electrode with a flexible printed circuit board by the side surface of a piezoelectric element. It is sectional drawing which shows an example of the conventional ultrasonic probe which connects both a signal electrode and a ground electrode with a flexible printed circuit board in the back surface of a piezoelectric element. It is an exploded view which shows an example of the conventional ultrasonic probe which connects both a signal electrode and a ground electrode with a flexible printed circuit board in the back surface of a piezoelectric element.

(First embodiment)
The ultrasonic probe according to the first embodiment will be described below with reference to FIGS. 1 and 2 and FIG.

  As shown in FIG. 1, the ultrasonic probe according to the present embodiment includes a piezoelectric vibration composed of one or more piezoelectric elements 10 in which a ground electrode 12 is installed on the ultrasonic transmission surface and a signal electrode 11 is installed on the back surface. A component 1 and a backing material 3 superimposed on the back surface of the piezoelectric vibration component 1 are provided. A flexible printed circuit board 2 is provided between the piezoelectric vibration component 1 and the backing material 3. In addition, as shown in FIG. 6, an acoustic matching layer 4 composed of a first acoustic matching layer 41 and a second acoustic matching layer 42 (conductor) is provided on the ultrasonic wave transmission surface of the piezoelectric vibration component 1. The acoustic lens 6 is provided so as to overlap in this order. A flexible printed circuit board 5 is interposed between the first acoustic matching layer 41 and the second acoustic matching layer 42, and a signal from the ground electrode 12 is drawn out.

  Hereinafter, the structure of each part is demonstrated concretely. In the following description, the ultrasonic scanning direction is the Z-axis direction (perpendicular to the plane of FIG. 1), the ultrasonic convergence direction is the Y-axis direction (vertical direction of the plane of FIG. 1), the Z-axis and Y-axis. The direction orthogonal to both axes is defined as the X-axis direction (the left-right direction on the paper surface of FIG. 1). In the Y-axis direction, the upper side is referred to as the ultrasonic wave transmission surface side, and the lower side is referred to as the back surface side.

  The piezoelectric vibration component 1 is configured by arranging at least one piezoelectric element 10 in which the signal electrode 11 and the ground electrode 12 are arranged in the scanning direction (Z-axis direction) (piezoelectric element 10, signal electrode 11, and The ground electrode 12 will be described later). As shown in FIG. 2, the piezoelectric vibration component 1 according to the present embodiment has a rectangular shape when viewed from the Y-axis direction. In the following description, it is assumed that the piezoelectric vibration component 1 includes a plurality of (two or more) piezoelectric elements 10.

  The piezoelectric element 10 has a piezoelectric effect, and for example, piezoelectric ceramics such as zinc oxide (ZnO) and lead zirconate titanate (PZT) are used.

  The signal electrode 11 is disposed so as to cover almost the entire back surface of the piezoelectric element 10. Specifically, considering the difference in processing accuracy of the piezoelectric element 10 and the signal electrode 11, the signal electrode 11 is formed so as to cover the entire back surface of the piezoelectric element 10 after processing. As a material of the signal electrode 11, a metal such as gold, silver, or copper having good conductivity is used.

  The ground electrode 12 is disposed so as to cover almost the entire ultrasonic wave transmission surface of the piezoelectric element 10. Specifically, considering the difference in processing accuracy of the piezoelectric element 10 and the ground electrode 12, the ground electrode 12 is formed so as to cover the entire ultrasonic wave transmission surface of the piezoelectric element 10 after processing. This is because a voltage is applied between the ground electrode 12 and the signal electrode 11, so that the portion covered with the ground electrode 12 becomes a part that is actually driven, and it is desirable to make the ground electrode 12 wider. .

  The signal electrode 11 and the ground electrode 12 are arranged for each piezoelectric element 10, and the signal electrode 11 and the ground electrode 12 of each piezoelectric element 10 are separated by a cutting groove that divides the piezoelectric vibrating component 1 into each piezoelectric element 10. The signal electrode 11 and the ground electrode 12 of the other piezoelectric element 10 are electrically separated.

  The backing material 3 absorbs ultrasonic waves propagating to the back side of the piezoelectric element 10 and is disposed on the back side of the piezoelectric vibration component 1. The material of the backing material 3 is not particularly limited, but rubber having excellent sound absorption is used.

  The flexible printed circuit board 2 transmits a drive signal to the piezoelectric element 10 and transmits a reception signal obtained by converting a reflected wave into an electric signal to an electric circuit. The flexible printed circuit board 2 is provided between the piezoelectric vibration component 1 and the backing material 3. Intervene in.

  The flexible printed circuit board 2 includes a substrate body 20 and a second protective layer 24. The substrate body 20 includes a base layer 21, a signal wiring layer 22, and a first protective layer 23 that are sequentially stacked from the backing material 3 toward the piezoelectric element 10.

  The signal wiring layer 22 includes an electrode connection portion 221 connected to the signal electrode 11 and an electrode lead-out portion 222 that extends the electrode connection portion 221 along the base layer 21 in the X-axis direction. As a material of the signal wiring layer 22, a metal such as gold, silver, or copper having good conductivity is used. Hereinafter, a portion corresponding to the electrode connecting portion 221 of the base layer 21 is referred to as a base layer exposed portion 211.

  The first protective layer 23 includes a piezoelectric element joint portion 231 corresponding to the ultrasonic wave transmission surface side of the backing material 3, and a side surface protection portion 232 that is bent along the side surface of the backing material 3.

  The piezoelectric element bonding portion 231 has a region slightly larger than the portion corresponding to the ultrasonic wave transmission surface side of the electrode connection portion 221 removed. That is, an opening 01 that is slightly larger than the electrode connection portion 221 is formed in the piezoelectric element bonding portion 231 with respect to the Y-axis direction. Thereby, the electrode connection part 221 and the base layer exposure part 211 are exposed from the flexible printed circuit board 2 to the signal electrode 11 side formed on the back surface of the piezoelectric element 10.

  The second protective layer 24 is interposed between the backing material 3 and the substrate body 20, and a portion where the electrode connection portion 221 of the substrate body 20 is exposed (the base layer exposed portion 211 and the region corresponding to the range A in FIG. 1). The electrode connecting portion 221) is raised toward the piezoelectric element 10. This raised portion corresponds to a raised portion. The formation range of the second protective layer 24 almost corresponds to the formation range of the electrode connection portion 221. However, if the formation range of the second protective layer 24 is limited to the inside of the opening 01 formed in the piezoelectric element joint portion 231 (range A in FIG. 1), it may be smaller or larger than the electrode connection portion 221. It doesn't matter.

  Here, the thickness of the second protective layer 24 will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of the flexible printed circuit board according to the first embodiment. As shown in FIG. 3, the thickness d4 of the second protective layer 24 is set to the thickness d3 of the first protective layer 23. Accordingly, the thickness from the backing material 3 to the piezoelectric element bonding portion 231 (the sum d1 + d2 + d3 of the thickness d1 of the base layer 21, the thickness d2 of the signal wiring layer 22, and the thickness d3 of the first protective layer 23). Is the thickness from the backing material 3 to the electrode connecting portion 221 (the sum d4 + d1 + d2 of the thickness d4 of the second protective layer 24, the thickness d1 of the base layer 21, and the thickness d2 of the signal wiring layer 22). equal. The electrode connection part 221, the piezoelectric element joining part 231, and the second protective layer 24 are formed in a substantially flat shape. That is, the thickness d4 of the second protective layer 24 is set to the thickness d3 of the first protective layer 23, so that the electrode connection portion 221 and the piezoelectric element bonding portion 231 are included in the same plane. become.

  The thickness d4 of the second protective layer 24 may be finely adjusted according to the material of the second protective layer 24. That is, if the second protective layer 24 is a soft material, it is slightly compressed by being sandwiched between the backing material 3 and the substrate body 20. Therefore, the thickness d4 of the second protective layer 24 may be set to d3 + da in consideration of the compression amount da of the second protective layer. The same applies to the case where a soft material is used for the first protective layer 23. In this case, when the piezoelectric vibration component 1 and the flexible printed circuit board 2 are joined, the thickness d3 of the first protective layer 23 is set so that the electrode connecting portion 221 and the piezoelectric element joining portion 231 are included in the same plane. Will be set.

  Conventional techniques may be used for joining the backing material 3 and the flexible printed circuit board 2 and joining the flexible printed circuit board 2 and the piezoelectric vibration component 1 (specifically, the signal electrode 11). As a general technique for joining the backing material 3 and the flexible printed circuit board 2, joining using an adhesive is well known. As a general technique for joining the flexible printed circuit board 2 and the piezoelectric vibration component 1, joining by soldering or joining by an adhesive is well known. When the flexible printed circuit board 2 and the piezoelectric vibration component 1 are joined, the signal electrode 11 is joined to the electrode connecting portion 221 and the piezoelectric element joining portion 231.

  When the backing material 3 and the flexible printed circuit board 2 are joined, the flexible printed circuit board 2 is bent along the side surface of the backing material 3 by the bent portion α. At this time, the electrode lead-out portion 222 of the signal wiring layer 22 is protected by the piezoelectric element joint portion 231 and the side surface protection portion 232 of the first protective layer 23.

  Hereinafter, the configuration of the ultrasonic probe will be described with reference to FIG. FIG. 6 is a schematic diagram of a configuration of an ultrasonic probe according to the present invention.

  The acoustic lens 6 converges the transmitted and received ultrasonic waves and shapes them into a beam shape, and is disposed on the ultrasonic wave transmission surface side of the acoustic matching layer 4 (the acoustic matching layer 4 will be described later). As the material of the acoustic lens 6, silicone or the like whose acoustic impedance is close to that of a living body is used.

  The acoustic matching layer 4 acoustically matches the piezoelectric element 10 and the acoustic lens 6, and is interposed between the piezoelectric element 10 and the acoustic lens 6. The acoustic matching layer 4 includes a first acoustic matching layer 41 and a second acoustic matching layer 42. The material of the first acoustic matching layer 41 and the second acoustic matching layer 42 is not particularly limited, but the acoustic impedance changes stepwise from the piezoelectric element 10 toward the acoustic lens 6, and The material is selected so that the second acoustic matching layer 42 located on the piezoelectric element 10 side has conductivity.

  The flexible printed circuit board 5 is interposed between the first acoustic matching layer 41 and the second acoustic matching layer 42 and draws an electrical signal from the ground electrode 12. The flexible printed circuit board 5 includes a base layer and a ground wiring layer (not shown), and the ground wiring layer draws an electrical signal from the ground electrode 12 through the second acoustic matching layer 42.

(Method for creating flexible printed circuit board 2 according to the first embodiment)
Next, a method for creating the flexible printed circuit board 2 will be described with reference to FIGS. 4 and 5 are diagrams for explaining a method of creating a flexible printed board in the first embodiment. 4A and 5A show plan views of the flexible printed circuit board 2 as viewed from the Z-axis direction. FIGS. 4B and 5B show the flexible printed circuit board 2 as XY. A cross-sectional view cut along a plane is shown.

  First, as shown in FIG. 4, the signal wiring layer 22 is laminated on the surface of the base layer 21 on the ultrasonic wave transmission surface side, and the second protective layer 24 is laminated on the back surface of the base layer 21. At this time, the second protective layer 24 is disposed at a position corresponding to the back side of the electrode connection part 221 of the signal wiring layer 22, that is, on the back side of the base layer exposed part 211.

  After the base layer 21, the signal wiring layer 22, and the second protective layer 24 are stacked, the stacked body is placed on a flat surface and pressed with a heat press or the like. As a result, the base layer exposed portion 211 and the electrode connecting portion 221 are raised by receiving pressure from the second protective layer 24.

  Next, as shown in FIG. 5, the first protective layer 23 is laminated on the ultrasonic wave transmission surface side of the electrode lead-out portion 222.

  The laminated first protective layer 23, signal wiring layer 22, and base layer 21 are pressed and pressure bonded by heat press. At this time, the electrode connection part 221 raised by the pressure from the second protective layer 24 and the first protective layer 23 are set in the same plane. Thus, the flexible printed board 2 is formed.

  In the above description, the first protective layer 23 is laminated and pressure-bonded after the base layer exposed portion 211 and the electrode connecting portion 221 are raised, but the base layer 21, the signal wiring layer 22, and the first protective layer 23 are bonded. After the layer 23 and the second protective layer 24 are stacked, the base layer exposed portion 211 and the electrode connecting portion 221 may be raised by pressurization such as heat press.

(Joining of the flexible printed circuit board 2 and the piezoelectric vibration component 1 according to the first embodiment)
The produced flexible printed circuit board 2 is bonded to the back surface of the piezoelectric vibration component 1. At this time, the electrode connection part 221 and the signal electrode 11 installed on the back surface of the piezoelectric element 10 are electrically connected. Conventional techniques may be used for joining the flexible printed circuit board 2 and the piezoelectric vibration component 1 (specifically, the signal electrode 11). Generally, joining by soldering or adhesive is well known.

(Join of flexible printed circuit board 2 and backing material 3 according to the first embodiment)
The backing material 3 is bonded to the back surface of the flexible printed circuit board 2. Conventional techniques may be used for joining the flexible printed circuit board 2 and the backing material 3, and generally joining by an adhesive is well known.

  Reference is now made to FIG. FIG. 1 is an exploded view of the piezoelectric element 10, the backing material 3, and the flexible printed circuit board 2 in the present embodiment. When the flexible printed circuit board 2 and the backing material 3 are joined, the flexible printed circuit board 2 is bent along the side surface of the backing material 3 at a bent portion α as shown in FIG.

  Next, as shown in FIG. 6, the acoustic matching layer 4, the flexible printed circuit board 5 that pulls out the ground electrode 12, and the acoustic lens 6 are bonded to the ultrasonic wave transmission surface of the piezoelectric vibration component 1, thereby the present embodiment. Is formed. For joining the piezoelectric vibration component 1, the acoustic matching layer 4, the flexible printed circuit board 5, and the acoustic lens 6, a conventional technique may be used.

  Reference is now made to FIG. FIG. 2 is a plan view of the flexible printed circuit board 2 in the first embodiment. When the piezoelectric vibration component 1, the acoustic matching layer 4, the flexible printed circuit board 5, and the acoustic lens 6 are joined, the piezoelectric vibration component 1 is cut along a plane parallel to the XY plane as shown in FIG. It is divided into a plurality of elements (piezoelectric element 10 in which signal electrode 11 and ground electrode 12 are arranged) in the axial direction.

  At this time, a cutting groove for dividing the piezoelectric vibration component 1 is formed from the back surface of the piezoelectric vibration component 1 (the bonding surface between the signal electrode 11 and the flexible printed circuit board 2) to at least the back surface of the piezoelectric element joint 231 and the back surface of the signal electrode 11. It is good to set the depth to the XZ plane β (see FIG. 1) located between the two. In the ultrasonic probe according to the present embodiment, the function of the ultrasonic probe can be realized even if the ultrasonic probe is cut to a deep position on the back side from the XZ plane β.

  As described above, according to the ultrasonic probe according to the present embodiment, the bent portion of the flexible printed board is covered with the protective layer (first protective layer 23) by the configuration in which the flexible printed board is soldered or adhesively bonded to the back surface of the piezoelectric element. It is possible to provide a protected ultrasonic probe.

  In addition, it is possible to install a signal electrode that applies a voltage to the piezoelectric element so as to cover almost the entire back surface of the piezoelectric element, so that an ineffective portion is not required and the ultrasonic probe can be miniaturized. It becomes.

(Modification 1)
Next, an ultrasonic probe according to Modification 1 will be described with reference to FIG. FIG. 9 is a plan view of the flexible printed circuit board 2 in the first modification. 7 and 8 are diagrams for explaining a method of creating the flexible printed circuit board 2 in the first modification. A method for creating the flexible printed circuit board 2 will be described later. Further, in the first modification, the description will be made by paying attention to the configuration of the piezoelectric vibration component 1 and the flexible printed board 2 different from the ultrasonic probe according to the first embodiment.

  As shown in FIG. 9, the piezoelectric vibration component 1 according to Modification 1 has a shape having a side surface portion 1 a in which at least a part of the side surface is formed in a planar shape when viewed from the Y-axis direction. At this time, the backing material 3 is shaped so as to have the same shape as the piezoelectric vibration component 1 when viewed from the Y-axis direction, corresponding to the shape of the piezoelectric vibration component 1.

  In addition, the flexible printed circuit board 2 according to the modified example 1 is formed such that the portion to be joined to the back surface of the piezoelectric vibration component 1 has the same shape as the piezoelectric vibration component 1 when viewed from the Y-axis direction. For example, in the example of FIG. 9, the piezoelectric vibration component 1, the backing material 3, and the portion of the flexible printed circuit board 2 that is joined to the back surface of the piezoelectric vibration component 1 are parallel to the Z axis when viewed from the Y-axis direction. The sides are shaped so as to form a straight octagon. At this time, the side surface portion 1a of the piezoelectric vibration component 1 and the side surface parallel to the YZ plane including the side parallel to the Z axis of the backing material 3 are preferably formed so as to be included in a continuous plane.

  The electrode lead-out portion 222 according to Modification 1 pulls out the electrode connection portion 221 along the side surface of the backing material 3 continuous with the side surface portion 1a through the bent portion α of the flexible printed board 2 corresponding to the side surface portion 1a. Install as follows. At this time, a portion (range B in FIG. 9) corresponding to the back surface of the piezoelectric element joint portion 231 of the electrode lead portion 222 may be drawn in a direction intersecting the XY plane.

  The first protective layer 23 according to Modification 1 has a different shape when viewed from the Y-axis direction, but, similarly to the configuration of the first protective layer 23 according to the first embodiment, the piezoelectric element bonding portion 231 and the side surface It is comprised with the protection part 232, and the opening 01 is provided.

  Further, the second protective layer 24 according to the first modification example has the same configuration as that of the second protective layer 24 according to the first embodiment, is formed with the same thickness as the first protective layer 23, and is a substrate. The portions of the main body 20 where the electrode connection portions 221 are exposed (the base layer exposure portions 211 and the electrode connection portions 221 corresponding to the range A in FIG. 9) are raised toward the piezoelectric element 10.

(Method for Creating Flexible Printed Circuit Board 2 According to Modification 1)
Next, a method for creating the flexible printed circuit board 2 will be described with reference to FIGS. 7 and 8 are diagrams for explaining a method for creating a flexible printed circuit board according to the first modification. FIGS. 7A and 8A are plan views of the flexible printed board 2 viewed from the Z-axis direction. FIGS. 7B and 8B show the flexible printed board 2 as XY. A cross-sectional view cut along a plane is shown. The method for creating the flexible printed circuit board 2 according to Modification 1 is the same as that for the flexible printed circuit board 2 according to the first embodiment.

  Specifically, first, as shown in FIG. 7, the signal wiring layer 22 is laminated on the surface of the base layer 21 on the ultrasonic wave transmission surface side, and the second protective layer 24 is laminated on the back surface of the base layer 21.

  When the base layer 21, the signal wiring layer 22, and the second protective layer 24 are laminated, these laminated bodies are pressed by heat press or the like. As a result, the base layer exposed portion 211 and the electrode connecting portion 221 are raised by receiving pressure from the second protective layer 24.

  Next, as shown in FIG. 8, the first protective layer 23 is laminated on the surface of the signal wiring layer 22 on the ultrasonic wave transmission surface side.

  The laminated first protective layer 23, signal wiring layer 22, and base layer 21 are pressed and pressure bonded by heat press. At this time, the electrode connection part 221 raised by the pressure from the second protective layer 24 and the first protective layer 23 are set in the same plane. Thus, the flexible printed board 2 is formed.

  As in the first embodiment, after the base layer 21, the signal wiring layer 22, the first protective layer 23, and the second protective layer 24 are stacked, the base layer is pressed by heat press or the like. The layer exposure part 211 and the electrode connection part 221 may be raised.

(Division | segmentation with respect to the scanning direction of the piezoelectric vibration component 1 which concerns on the modification 1)
Reference is now made to FIGS. FIG. 9 is a plan view of the flexible printed circuit board 2 in the first modification. FIG. 10 is an exploded view of the piezoelectric element, the backing material, and the flexible printed circuit board in Modification 1. When the piezoelectric vibration component 1, the acoustic matching layer 4, the flexible printed circuit board 5, and the acoustic lens 6 are joined as in the first embodiment, the piezoelectric vibration component 1 is cut along the XY plane as shown in FIG. In the scan direction (Z-axis direction), it is divided into a plurality of elements.

  At this time, a cutting groove for dividing the piezoelectric vibration component 1 is formed from the back surface of the piezoelectric vibration component 1 (the bonding surface between the signal electrode 11 and the flexible printed circuit board 2) to at least the back surface of the piezoelectric element joint 231 and the back surface of the signal electrode 11. It is set as the depth to XZ plane (beta) (refer FIG. 10) located in between.

  Accordingly, the electrode lead-out portion 222 located on the back surface of the piezoelectric element joint portion 231 can be disposed at a position intersecting the cutting groove on the XZ plane without being cut by the cutting groove. As a result, the electrode lead-out portion 222 can be pulled out along the side surface of the backing material 3 continuous with the side surface portion 1a through the bent portion α. Therefore, the piezoelectric vibration component 1 only needs to have the side surface portion 1 a in which at least a part of the side surface is formed in a planar shape, and a piezoelectric vibrator other than a rectangle can be used for the piezoelectric vibration component 1.

  As described above, in addition to the characteristics of the ultrasonic probe according to the first embodiment, the ultrasonic probe according to Modification 1 can use a piezoelectric vibrator other than a rectangle (for example, an octagonal piezoelectric vibrator). Therefore, an ultrasonic probe with reduced side lobes can be realized at low cost.

  In the above description, the case where the shape of the piezoelectric vibrating component 1 viewed from the Y-axis direction is an octagon has been described as an example, but this is not limited to an octagon. For example, FIG. 11 is a plan view of a flexible printed board in the case of using a piezoelectric element in which a part of a circle is cut out linearly. As shown in FIG. 9 and FIG. 11, the shape is not limited as long as the side surface of the piezoelectric vibration component 1 that is continuous with the side surface of the backing material 3 from which the electrode lead-out portion 222 is drawn is a flat surface.

  In the above description, the side surface parallel to the YZ plane of the piezoelectric vibration component 1 is formed in a planar shape, but this is not limited to the side surface parallel to the YZ plane. It suffices to have a side surface part of which side surface is partly formed on a plane when viewed from the Y-axis direction, and the electrode lead-out portion 222 extends along the side surface of the backing material 3 continuous with the side surface portion. If it is, the structure will not be limited.

DESCRIPTION OF SYMBOLS 1 Piezoelectric vibration part 10 Piezoelectric element 11 Signal electrode 12 Ground electrode 2 Flexible printed circuit board 21 Base layer 211 Base layer exposure part 22 Signal wiring layer 221 Electrode connection part 222 Electrode extraction part 23 1st protective layer 231 Piezoelectric element junction part 232 Side surface Protection part 24 2nd protection layer 3 Backing material 4 Acoustic matching layer 5 Flexible printed circuit board 6 Acoustic lens

Claims (4)

A piezoelectric vibration component composed of one or more piezoelectric elements each having a ground electrode on the ultrasonic wave transmission surface and a signal electrode on the back surface;
A backing material superimposed on the back surface of the piezoelectric vibration component;
An ultrasonic probe comprising a flexible printed circuit board interposed between the piezoelectric vibration component and the backing material,
The flexible printed circuit board is formed along the base layer on a surface of the base layer having a raised portion in part and on the piezoelectric vibration component side of the base layer, and a portion corresponding to the raised portion serves as the signal electrode. A signal wiring layer to be connected; and a protective layer that is formed on both sides of a part of the signal wiring layer corresponding to the raised portion and protects the signal wiring layer corresponding to a portion other than the raised portion. ,
A portion of the signal wiring layer corresponding to the raised portion is connected to a surface on the piezoelectric vibration component side and a back surface of the signal electrode,
An ultrasonic probe characterized in that a surface of the protective layer on the piezoelectric vibration component side and a back surface of the signal electrode are connected.   The surface of the protective layer on the piezoelectric vibration component side and a portion of the signal wiring layer corresponding to the raised portion on the side of the piezoelectric vibration component are formed on substantially the same plane. The ultrasonic probe according to claim 1. The piezoelectric vibration component is composed of two or more piezoelectric elements, and is rectangular when viewed from the direction of transmitting ultrasonic waves,
3. The signal wiring layer according to claim 1, wherein the signal wiring layer is formed so as to be drawn out in parallel with a plane including a cut surface that divides the piezoelectric vibration component into two or more piezoelectric elements. Ultrasonic probe. The piezoelectric vibration component is composed of two or more piezoelectric elements, and at least a part of the side surface is formed in a planar shape,
In a direction where at least a part of the wiring layer intersects a plane including a cut surface that divides the piezoelectric vibration component into two or more piezoelectric elements on the base layer facing a part of the back surface of the piezoelectric vibration component. The ultrasonic probe according to claim 1, wherein the ultrasonic probe is drawn out along a side surface of the backing material that is drawn out and is continuous with the planar side surface of the piezoelectric vibration component.

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