JP2006339748A - Ultrasonic probe and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the reflection of ultrasonic waves between substrates, and to obtain improved characteristics by partially removing an unneeded (trouble) portion on each substrate at an upper layer in a backing member. <P>SOLUTION: In an ultrasonic probe, the backing member 52 is composed of a backing body 73, and a plurality of substrates 72. Respective substrates 72 comprise a base layer 74 and a lead pattern. Each lead pattern comprises a plurality of leads. A plurality of protrusions are formed at an upper end on the substrate 72. More specifically, the unneeded (trouble) portion is removed on the substrate 72, thus filling the backing material between the protrusions, and hence preventing the ultrasonic waves from being reflected and propagated by the substrates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic probe and a method for manufacturing the same, and more particularly to a structure of a backing member incorporating a lead array and a method for manufacturing the same.

  The ultrasonic probe includes an array transducer that transmits and receives ultrasonic waves, a matching layer provided on the upper side of the array transducer, and a backing member provided on the lower side of the array transducer. The backing member generally exhibits an action of attenuating or absorbing ultrasonic waves emitted backward from the array transducer. If the backing member does not have good characteristics, the array transducer cannot exhibit its original characteristics sufficiently.

  The array vibrator is composed of a plurality of vibration elements. 2. Description of the Related Art In recent years, 2D array transducers are being put into practical use. The 2D array transducer is a two-dimensional array of a plurality of vibration elements, and is composed of, for example, hundreds or thousands of vibration elements. As a kind of 2D array transducer, a sparse 2D array transducer is also known that transmits and receives ultrasonic waves using a plurality of distributed effective elements.

  In order to individually connect signal lines to a large number of vibration elements constituting a 2D array transducer, a technique for embedding a two-dimensional lead array in a backing member has been proposed. That is, a plurality of signal lines are drawn from the lower side of the 2D array transducer. Various methods have been proposed as a method for manufacturing such a two-dimensional lead array built-in type backing member. Among them, a method using a flexible printed circuit (FPC) substrate (hereinafter simply referred to as “substrate”) is proposed. Attention has been paid. This is to embed a plurality of substrates in a backing material. If this type of substrate is used, advantages such as the ability to freely set the lead row pattern and the simple drawing of each lead can be obtained. According to a typical conventional technique, a plurality of backing plates and a plurality of substrates are alternately arranged while being bonded together with an adhesive (see Patent Documents 1 and 2). In addition, it is also possible to form a backing member by positioning a plurality of substrates in a mold, filling the mold with a backing material, and curing it. In addition, Japanese Patent Application No. 2004-164081 (application date: June 2, 2004) can be mentioned as an unpublished prior application related to the present application.

JP-A-7-131895 JP 2001-309493 A

  According to the experiments by the present inventors, in an ultrasonic transducer using a backing member incorporating a plurality of substrates, the frequency characteristics and beam directivity of the ultrasonic waves differ between the arrangement direction of the plurality of substrates and the direction orthogonal thereto. It has been confirmed. That is, it is assumed that the structure of the backing member (that is, the arrangement of a plurality of substrates) affects the characteristics of the array transducer. As the cause, the influence of the ultrasonic wave propagating through the substrate itself in the backing member, and internal reflection (multiple reflection) between the substrates can be considered. Note that the same problem is expected to occur when a substrate other than the FPC substrate is used.

  The above problem will be described with reference to FIGS. FIG. 1 shows a conventional backing member 10. The backing member 10 includes a backing body 12 made of a backing material and a plurality of substrates 14. Each substrate 14 includes a film-like base layer made of an insulating member and a lead pattern formed on one surface thereof. The lead pattern has a plurality of leads 18. Each lead 18 extends in the Z direction in FIG. As shown in FIG. 1, each substrate 14 has a rectangular shape, and its upper surface is exposed on the upper surface of the backing member 10. FIG. 2 shows a transducer assembly disposed in the case of the ultrasonic probe. The vibrator assembly includes the above-described backing member 10, a vibration element array (array vibrator) 20, a matching element array (matching layer) 22, and the like. The vibration element array 20 includes a plurality of vibration elements 24 that are two-dimensionally arranged, and the matching element array 22 also includes a plurality of matching elements 38 that are two-dimensionally arranged. Although 3 × 3 vibrating elements are shown in FIG. 2, hundreds to thousands of vibrating elements are actually provided. A signal electrode 26 is individually provided on the lower surface side of each vibration element 24, and a common ground electrode 36 is provided on the upper surface side of the plurality of vibration elements 24.

  The plurality of vibration elements 24 are manufactured by forming a plurality of separation grooves 28 in the X direction and the Y direction with respect to one plate made of a vibration material. The lower end of each separation groove 28 slightly enters the upper layer portion of the backing member 10. This is to completely separate the plate into a plurality of vibration elements. Similarly, the plurality of matching elements 38 are manufactured by forming a plurality of separation grooves 32 in the X direction and the Y direction with respect to one plate made of a matching material.

  FIG. 3 shows a schematic view of the backing member 10 as viewed from above. In FIG. 3, a plurality of substrates 14A, 14B, and 14C are shown, and a broken line 40 indicates a vibration element section. Now, paying attention to the center vibration element 42, some of the ultrasonic waves radiated from the back surface thereof propagate in the horizontal direction and travel to the adjacent substrates 14A and 14C, thereby Reflected (see symbols 44 and 46). That is, an unnecessary reflected wave is generated. On the other hand, among the ultrasonic waves radiated from the back surface of the vibration element 42, another part of the ultrasonic waves directly propagates on the substrate 14B (see reference numerals 48 and 50), and the ultrasonic waves are transmitted to the adjacent vibration elements. Goes around.

  For the above reasons, the frequency characteristics and directivity characteristics of the array transducer are adversely affected. In particular, since there is a difference in ultrasonic response between the X direction and the Y direction in the backing member, the directivity of the ultrasonic beam is different between the X direction and the Y direction. As a result, there is a difference in image quality between the tomographic image in the X direction and the tomographic image in the Y direction.

  An object of the present invention is to provide an ultrasonic probe having good characteristics.

  Another object of the present invention is to improve the characteristics of a backing member provided in an ultrasonic transducer.

  Another object of the present invention is to eliminate or reduce the problem caused by the ultrasonic wave propagating in the horizontal direction in the backing member.

  Another object of the present invention is to easily and accurately manufacture a backing member having good characteristics.

(1) The present invention is a backing member having an array transducer composed of a plurality of transducer elements and a plurality of substrates provided below the array transducer and electrically connected to the array transducer. Each of the substrates has a base layer and a plurality of leads provided in the base layer, and a plurality of protrusions protruding toward the array transducer side are provided at an upper end portion of the substrates. And a plurality of cutout portions are alternately formed, each protrusion has a lead protrusion element, and the upper layer portion of the backing member includes a backing material and a protrusion array embedded in the backing material. It is characterized by comprising.

  According to the above configuration, the backing member has a plurality of substrates, and each substrate has a plurality of protrusions. Thereby, the protrusion part array is comprised in the backing material in the upper layer part of the backing member. That is, the periphery (between adjacent protrusions) of each protrusion including the lead protrusion elements is filled with the backing material. In this way, since unnecessary (faulty) portions of each substrate are partially removed in the upper layer portion of the backing member, the ultrasonic wave wraps around due to the propagation of the substrate itself and the reflection of the ultrasonic waves generated between the substrates. The problem which becomes remarkable in the upper layer part can be reduced and eliminated.

  The substrate is preferably a thin film FPC, but may be other than that. The array transducer is preferably a 2D array transducer including a sparse array transducer, but may be a 1.5D array transducer or the like. Although it is desirable to configure each protrusion as an elongated shape, a shape that tapers upward may be employed. The cutout portion can be configured in various forms such as a triangle and a trapezoid spreading upward in addition to a rectangle.

  Although a plurality of protrusions can be formed in advance for each substrate, generally, the strength of each protrusion becomes a problem, that is, it is difficult to maintain an appropriate arrangement of the plurality of protrusions. As will be described later, after forming a backing block (laminate) using a plurality of substrates, the backing block is processed so that a plurality of protrusions are formed on each substrate as a result. Is desirable.

  Preferably, the width of each notch is larger than the width of each separation groove formed between the vibration elements in the array transducer. Desirably, the depth of each notch is larger than the depth of entry into the backing member in each separation groove.

  In general, when the isolation groove (element isolation groove) is formed, the upper side of the substrate is partially cut. However, the isolation groove is an extremely thin slit and cannot solve the various problems described above. Further, when the width is increased, the size of the vibration element itself is decreased. According to the above configuration, a notch (or a notch groove to be described later) is formed separately from such a separation groove, and an unnecessary portion is removed after leaving only a necessary portion of the substrate. Can effectively deal with various problems.

  Preferably, the protrusion amount of each protrusion is at least twice the wavelength of the ultrasonic wave transmitted and received by the array transducer. It is desirable that the protrusion amount of each protrusion, in other words, the depth of the notch, be set to a size that can effectively prevent ultrasonic waves from wrapping around and reflecting. Considering the attenuation of the ultrasonic waves in the backing member, the protrusion amount of each protrusion is preferably at least twice the wavelength of the ultrasonic wave, and more preferably at least three times. If the amount of protrusion is excessively large, there will be a problem with the strength of each protrusion (or a protrusion wall, which will be described later). Therefore, it is desirable to set the protrusion amount in consideration of this.

  For example, when the attenuation of the ultrasonic wave in the backing material is 40 dB / cm · MHz and the frequency of the ultrasonic wave is 3 MHz, a one-way attenuation is considered. To obtain 6 dB attenuation, a depth of 0.5 mm is required. Yes, a depth of 0.83 mm is required to obtain 10 dB attenuation, and a depth of 1.66 mm is required to obtain 20 dB attenuation. In general, an ultrasonic wave of several to several tens of MHz is used, and a backing material of about 20 to 60 dB / cm · MHz is used. Therefore, the protruding amount of the protruding portion is 0.3 to 4.0 mm. It is desirable to set within the range, and it is particularly desirable to set within the range of 0.5 to 2 mm. Of course, these values may vary depending on various conditions.

  Preferably, each protrusion includes a base layer protruding element having an elongated shape and the lead protruding element having an elongated shape. In each projecting portion, the base layer projecting element functions as a reinforcement or forming medium for the lead projecting element. In addition, you may comprise each protrusion part by the linear electrically-conductive member connected with the lead pattern on a board | substrate. That is, a comb-like linear member array may be separately added to the upper side of each substrate.

  Preferably, each of the leads is electrically connected to the lead projecting element, the lead projecting element provided on the lower end side of the lead projecting element, and spread in the horizontal direction, to the lead projecting element via the lead relay element. And connected lead body elements. According to this configuration, the lead relay element spreading in the horizontal direction can have a degree of freedom in the formation position of the lead projecting element with reference to the lead body element. Preferably, each of the substrates is a flexible circuit board. In the case of a flexible circuit board, the lead pattern can be freely formed by a technique such as etching, so that it can be easily applied to, for example, a sparse array transducer.

(2) The present invention provides an array transducer composed of a plurality of transducer elements arranged on a plane defined in the X direction and the Y direction, and provided below the array transducer, A member for attenuating ultrasonic waves radiated rearward, and having a plurality of substrates arranged in the X direction and electrically connected to the array transducer, and an upper layer of the backing member A plurality of cutout grooves arranged in the Y direction and extending in the X direction are formed in the portion, whereby a plurality of protrusions are formed at the upper end portion of each substrate, and each protrusion has the array vibration. It has a lead projecting element while projecting toward the child side, and each notch groove is filled with a backing material, whereby the adjacent projecting portions in the backing member are filled with the backing member.

  According to the above configuration, the plurality of substrates are cut transversely by forming the plurality of notch grooves in the upper layer portion of the backing member, and as a result, a plurality of substrates are formed in the upper layer portion of the backing member (between adjacent notch grooves). Projecting walls are formed, that is, a plurality of projecting portions are formed on each substrate. Since the plurality of notch grooves are filled with the backing member, the space between the protrusions is filled with the backing material. As a result, the portions where the ultrasonic waves have sneak or reflected are removed from each substrate, so that these problems can be effectively dealt with while using a simple technique.

  Preferably, the bottom surface of each notch groove is flat. Preferably, the bottom surface of each notch groove is composed of one or a plurality of inclined surfaces. If the reflection of the ultrasonic wave at the bottom surface (boundary surface) can be ignored, the bottom surface may be leveled. However, if the reflection of the ultrasonic wave at that point cannot be ignored, multiple reflections will be made with the bottom surface as some inclined surface. It is desirable to avoid it as much as possible.

  Desirably, the backing material filled in each notch groove is substantially the same as the backing material constituting the backing body of the backing member. Preferably, the width in the Y direction at the upper end of each protrusion is defined by the interval between two notch grooves passing through both sides thereof.

(3) The present invention includes a step of manufacturing a backing member having a plurality of substrates, a step of providing a plurality of vibration elements above the backing member, and a step of providing a plurality of matching elements above the plurality of vibration elements. In the step of manufacturing the backing member, a plurality of protrusions are formed at the upper end of each substrate, each protrusion has a lead protrusion element, and in the step of providing the plurality of vibration elements, The plurality of lead projecting element end faces exposed on the upper surface of the backing member are electrically connected to the plurality of vibration elements.

  According to the above configuration, when the backing member having a plurality of substrates is manufactured, a plurality of protrusions are formed on each substrate. The backing member is a method of alternately laminating a plurality of substrates and a plurality of spacer plates, a method of inserting a plurality of substrates into a plurality of slits formed in the backing plate, a positioning by positioning the plurality of substrates in the mold It can be manufactured by the method of pouring material. The plurality of vibration elements can be manufactured by two-dimensionally cutting a plate made of a vibration material, and the same applies to the plurality of matching elements. A plurality of vibration elements and a plurality of matching elements can be simultaneously manufactured by cutting. In this case, an individual electrode is formed on the upper surface side of each vibration element instead of the common electrode.

  Preferably, the step of manufacturing the backing member includes a step of manufacturing a backing block using the plurality of substrates, and a plurality of notches are formed in the backing block, thereby forming an upper end portion of each substrate. Forming the plurality of protrusions, and filling the plurality of cutout grooves with a backing material.

  According to this method, by forming a plurality of cutout grooves after the first manufacturing of the backing block, unnecessary portions on each substrate can be easily removed, that is, a plurality of protrusions can be easily formed. Even in that case, since each protrusion part does not exist independently by itself, but is held by the backing material before and after the protrusion part, it is possible to construct a good strength state. As a result, it is possible to prevent the problem that the protrusions are bent unexpectedly when the backing material is poured.

  Preferably, the step of manufacturing the backing member includes a step of manufacturing a plurality of processed substrates in which a plurality of cavities are formed between leads at the upper end as the plurality of substrates, and a backing member in each of the cavities. A step of manufacturing a backing block using the plurality of processed substrates while filling, and a step of removing the upper end edge of the backing block and forming the plurality of protrusions at the upper end of each processed substrate. . According to this method, a plurality of cavities are formed in each substrate, that is, the plurality of protrusions are formed in advance with their upper ends connected to each other. Therefore, after filling each cavity with a backing material and securing the strength of each protrusion, the connecting portion is removed.

  Preferably, the step of manufacturing the backing member includes a step of manufacturing a plurality of processed substrates in which a plurality of cavities are formed between leads at the upper end as the plurality of substrates, and a backing member in each of the cavities. Filling, and then removing the upper edge of each processed substrate to form the plurality of protrusions on the upper end of each processed substrate, and using the plurality of processed substrates on which the plurality of protrusions are formed And manufacturing the backing member. According to this method, the backing block is manufactured after the strength is secured on a substrate basis by pouring the backing material into the cavity of each substrate, and its upper edge is removed.

  Preferably, before the formation of the plurality of cutout grooves, the upper ends of the leads in the substrates are formed wide, and when the plurality of cutout grooves are formed, the upper ends of the leads are partially removed. Thus, the lead protruding element remains. According to this configuration, even if there is a positioning error on each substrate, the upper end of each lead is formed wide, so even if multiple notches are formed, multiple protrusions can be reliably formed Can do.

  As described above, according to the present invention, an ultrasonic probe having good characteristics can be provided. In particular, the characteristics of the backing member provided in the ultrasonic transducer can be improved. Alternatively, according to the present invention, a backing member having good characteristics can be easily or accurately manufactured.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 4 shows a vibrator assembly according to this embodiment. This transducer assembly is arranged in a case (not shown) of the ultrasonic probe. The ultrasonic probe is brought into contact with the surface of the living body or inserted into the body cavity of the living body. A reception signal is acquired by transmitting and receiving an ultrasonic wave in the ultrasonic probe, and an ultrasonic image is formed based on the reception signal in a medical ultrasonic diagnostic apparatus to which the ultrasonic probe is connected. Is done. As an ultrasonic image, a two-dimensional tomographic image, a two-dimensional Doppler image, a three-dimensional image, and the like are known.

  In FIG. 4, the vibrator assembly includes a backing member 52, a vibration element array (array vibrator) 54, a matching element array (matching layer) 56, and the like. In FIG. 4, the X direction and the Y direction indicate the arrangement direction of the plurality of vibration elements 58, and the Z direction indicates the ultrasonic wave transmission / reception direction.

  The backing member 52 is composed of a backing body 73 made of a backing material and a plurality of substrates 72. The backing material is obtained by adding, for example, tungsten or silicone rubber as an additive to an epoxy resin. Each substrate 72 includes a film-like base layer 74 and a lead pattern formed on one surface of the base layer 74. The lead pattern is composed of a plurality of leads 76. The lead 76 is formed by etching a copper layer formed on the base layer 74. In order to improve conductivity and adhesion, nickel or gold may be further plated. The thickness is, for example, several μm to 30 μm. The total thickness of the substrate 72 is, for example, several tens to hundreds of micrometers including the thickness of the leads 76. The base layer 74 is made of an insulating member such as polyimide. The structure of the backing member 52 and the form of each substrate 72 will be described in detail later.

  A vibrating element array 54 is provided above the backing member 52. The vibration element array 54 includes a plurality of vibration elements 58 arranged in the X direction and the Y direction, that is, two-dimensionally arranged. In FIG. 4, only a small number of vibration elements 58 are shown, but actually, the vibration element array 54 is composed of hundreds to thousands of vibration elements 58. The vibration element array 54 may be a so-called sparse type 2D array vibrator.

  The vibration element array 54 is manufactured by forming a plurality of separation grooves 60 aligned in the X direction and the Y direction with respect to one plate made of a vibration material. A filling member 62 is filled in each separation groove 60. Reference numeral 59 represents a signal electrode provided for each vibration element 58, and reference numeral 64 represents a common ground electrode for the plurality of vibration elements 58. The lower end of each separation groove 60 slightly enters the inside from the upper surface of the backing member 52, but in this embodiment, the amount of entry is very small and is shallower than the depth of the notch or notch groove described later. The groove width is also small.

  A matching element array 56 is provided above the vibration element array 54. The matching element array 56 includes a plurality of matching elements 70. The matching elements 70 are manufactured by forming a plurality of separation grooves 66 aligned in the X direction and the Y direction with respect to a single plate made of a matching material. A filling material 68 is filled in each separation groove 66. It is possible to form the separation groove 66 and the separation groove 60 simultaneously. In this case, a ground electrode is provided for each vibration element 58.

  Next, the backing member 52 will be further described. Each substrate 72 has a plurality of protrusions formed at the upper end thereof as described below with reference to FIG. In FIG. 4, two upper end surfaces of the two protrusions are shown. When the backing member 52 is divided into the upper layer portion 73A and the other portion (lower layer portion) 73B, the upper layer portion 73A forms a protruding portion array composed of a plurality of protruding portions, and the upper end surface of each protruding portion. Is exposed on the upper surface of the backing member 52. In the lower layer portion 73B of the backing member 52, the base layer main body of each substrate 72 exists. Incidentally, in FIG. 4, in the backing body 73, the upper layer portion 73A and the lower layer portion 73B are integrated members. However, as will be described later, the backing body 73 is constituted by a plurality of parts. May be.

  FIG. 5 shows the above-described substrate 72 as a perspective view. As described above, the substrate 72 includes the base layer 74 and the plurality of leads 76. In the present embodiment, as shown in FIG. 5, the upper end portion of the substrate 72 is partially removed, and specifically, a plurality of cutout portions 80 are formed in a section belonging to the upper layer portion 73A. As a result of forming the plurality of notches 80, a plurality of protruding portions 82 protruding upward are formed at the upper end portion of the base layer 74. Each protrusion 82 includes a base layer protrusion element 74A and a lead protrusion element 76A. The lead projecting element 76A constitutes the upper end portion of the lead 76, and the base layer projecting element 74A is a part of the base layer 74 and functions as a reinforcing material or a support medium for the lead projecting element 76A. The upper end surface of the projecting portion 82 includes an upper end surface 74B of the base layer projecting element 74A and an upper end surface 76B of the lead projecting element 76A. As described above, the upper end surface of the projecting portion 82 is exposed on the upper surface of the backing member, and in particular, the upper end surface 76B of the lead projecting element 76A is electrically connected to the signal electrode of the corresponding vibration element.

  As described above, the plurality of projecting portions 82 are formed on the upper end portion of the substrate 72, and the base layer 74 is composed of the base layer main body 74C and the plurality of base layer projecting elements 74A. That is, unnecessary portions in the base layer 74 are removed by forming the plurality of notches 80. However, if the plurality of notches 80 are formed in advance in the substrate 72, the strength of each protrusion 82 becomes insufficient, and it becomes difficult to sufficiently maintain the arrangement of the plurality of protrusions 82. Therefore, in this embodiment, as will be described later, by forming a plurality of substrates together with a backing material before forming the plurality of notches 80 as described above, and then forming a plurality of notches, As a result, a plurality of notches 80 are formed for each substrate 72.

  In the present embodiment, the inter-element pitch for the plurality of vibration elements is, for example, 0.3 mm, and the size in the Y direction of the protruding portion 82 is, for example, 0.1 mm. Therefore, the distance between two adjacent protrusions 82 is, for example, 0.2 mm. Of course, those numerical values are examples, and other numerical values may be adopted. It is desirable that the size of the protruding portion 82 in the Y direction be as small as possible as long as electrical connection can be satisfactorily performed. That is, by increasing the size of the notch 80, problems such as reflection of ultrasonic waves and propagation of ultrasonic waves can be more effectively prevented.

  The depth of each notch 80, that is, the protrusion amount of each protrusion 82 is preferably set to at least twice the wavelength of the ultrasonic wave, and more preferably set to at least three times the wavelength of the ultrasonic wave. Although the protrusion amount may be increased, it is desirable to set the projection amount to, for example, three times the wavelength of the ultrasonic wave because there may be a problem in strength. For example, when the ultrasonic velocity in the backing member is 2000 m / s and the ultrasonic frequency is 5 MHz, the wavelength is 0.4 mm. Therefore, the depth of the notch 80 is, for example, 1.2 mm. be able to. The numerical value can vary depending on various conditions, and is generally set within a range of 0.3 to 4.0 mm, and particularly preferably within a range of 0.5 to 2.0 mm.

  The shape of each protrusion 82 shown in FIG. 5 is preferably an elongated shape as shown in the figure, but it is also possible to adopt a form that tapers upward, for example. Similarly, various shapes such as a trapezoid and a triangle extending upward in addition to a rectangle can be adopted as the shape of each notch 80. However, as will be described later, when the reflection of ultrasonic waves at the bottom surface in a plurality of notch grooves becomes a problem, the bottom surface is configured to prevent ultrasonic reflection as much as possible. It is desirable to do.

  When the backing member 52 shown in FIG. 4 is manufactured, a plurality of conventional substrates that are not formed with the plurality of notches described above are integrated together with a backing material to form a cube-shaped backing block. . Then, as shown in FIG. 6, a plurality of cutout grooves 84 are formed with a certain arrangement in the Y direction with respect to the backing block 83. Each notch groove 84 is a transverse groove extending in the X direction. In addition, each notch groove 84 can be formed by cutting with a dicing saw, cutting with a laser, cutting with sandblast, or the like.

  When the plurality of cutout grooves 84 are formed, the plurality of protruding walls 86 are left at the upper end portion of the backing block 83. The plurality of protruding walls 86 are aligned at a predetermined interval in the Y direction, specifically, are aligned at a vibration element pitch, and each protruding wall 86 is a wall portion extending in the X direction. Each protruding wall 86 is constituted by a plurality of protruding portions 82 and a backing material portion 88 existing therebetween as shown. That is, each protrusion 82 is physically held by the plurality of backing material portions 88, and even if the strength of the protrusion 82 is insufficient, the protrusions depend on the strength of the entire protrusion wall 86. The pattern of the array can be maintained. In FIG. 6, reference numeral 83 </ b> A indicates the upper layer portion of the backing block 83, and reference numeral 83 </ b> B indicates the lower layer portion of the backing block 83.

  When the plurality of protruding walls 86 are formed on the backing block 83 as described above, the backing material 90 is then filled into the plurality of notch grooves 84 and cured as shown in FIG. . The backing material 90 is the same as the backing material constituting the backing body 73 described above. Thus, the backing member 92 is completed. This backing member 92 corresponds to the backing material 52 shown in FIG. In FIG. 7, reference numeral 94 represents a vibration element array. The upper end surface of each protrusion appears at the center of the lower surface of each vibration element.

  Next, the manufacturing method of the ultrasonic probe according to the present embodiment will be described in more detail with reference to FIG. First, in S101, the above-described backing block is manufactured. Various methods can be given as a method for manufacturing the backing block, which will be described later with reference to FIGS.

  In S102, as shown in FIG. 6, a plurality of notch grooves are formed from the upper surface side of the backing block. As a result, a plurality of protruding walls are formed at the upper end of the backing block. In S103, each notch groove is filled with a backing material, that is, groove filling is performed.

  Next, in S104, a polishing process is performed on the upper surface of the backing member formed as described above. An electrode layer is formed on the upper surface. In this case, an electrode pad may be formed for each vibration element, or an electrode layer composed of one layer may be formed, and the electrode layer may be divided into a plurality of element electrodes by subsequent dicing.

  In S105, the piezoelectric plate is bonded to the upper surface of the backing member. This piezoelectric plate constitutes a plurality of vibration elements, and a known material such as PZT can be used, or a composite material can also be used. In S106, two-dimensional dicing is performed on the piezoelectric plate. That is, one piezoelectric plate is divided into a plurality of vibration elements. In S106, each dicing groove (separation groove) is filled with a filling material. The separation groove may be an air layer, but such clogging facilitates maintaining the acoustic and electrical characteristics over a long period of time.

  In S107, a common ground electrode is provided on the upper surfaces of the plurality of vibration elements. The ground electrode is, for example, a copper foil. In S107, an acoustic matching plate is bonded to the upper surface side of the ground electrode. In S108, the acoustic matching plate is two-dimensionally diced, and each dicing groove (separation groove) is clogged. In S109, necessary wiring is performed while the transducer assembly configured as described above is arranged in the probe case. This completes the ultrasonic probe.

  9 to 11 show a method for manufacturing a backing block. In the method shown in FIG. 9, a plurality of substrates 102 and a plurality of spacer plates 108 are alternately stacked to form a backing block 100. They are bonded by an adhesive. The spacer plate 108 is made of a backing material, and the substrate 102 is an FPC or the like as described above, and is made up of the base layer 103 and the lead pattern 104. The lead pattern 104 includes a plurality of leads 106 as described above.

  In the backing block 110 shown in FIG. 10, two backing materials 110R and 110L are bonded together to form one block, and slit rows 112 are formed in the block. The slit row 112 includes a plurality of slits 114, and a substrate 116 is inserted into each slit 114. A lead pattern 118 is formed on the substrate 116. After inserting the board | substrate 116 with respect to each slit 114 and positioning it, as shown by the codes | symbols 120 and 122 with respect to a block, cutting is performed and the backing block 110 is comprised by this.

  Further, as shown in FIG. 11, a plurality of substrates 124 are arranged between the two frames 121 and 123, and a backing material 126 is filled between the two frames 121 and 123, and then indicated by reference numerals 128 and 130. As described above, the upper surface and the lower surface may be cut. Further, as shown in FIG. 12, after two frames 121 and 123 are arranged in the mold 131 and the plurality of substrates 124 are positioned by them, the backing material 126 is filled in the mold 131 in the same manner as described above. You may do it.

  By the way, in the case where a plurality of cutout grooves are formed in the backing block, if each cutout groove is a simple rectangular groove, there is a problem as shown in FIG. That is, the backing member 92 is divided into an upper layer portion 83A and a lower layer portion 83B. In this case, the backing material 134 present in the upper layer portion 83A, the base layer body or the backing material 132 present in the lower layer portion 83B, Since the boundary surface 135 is horizontal and flat, the ultrasonic wave is reflected at the boundary surface 135 (see reference numeral 142). Such a reflected wave 142 causes multiple reflection, and may adversely affect the transmission / reception characteristics of the ultrasonic wave.

  Therefore, as shown in FIG. 14, it is desirable that the boundary surface between the upper layer portion 150A and the lower layer portion 150B be one or more inclined surfaces. In the example shown in FIG. 14, the backing material 154 in the upper layer portion 150 </ b> A has a triangular shape protruding downward, thereby forming two inclined surfaces 156 </ b> A and 156 </ b> B. Incidentally, reference numeral 152 represents a base layer body or backing material present in the lower layer 150B.

  According to the backing member 150 shown in FIG. 14, since two inclined surfaces 156A and 156B are formed for each separation groove, as indicated by reference numeral 158, any ultrasonic wave radiated backward from the vibration element is selected. The slopes 156A and 156B are reflected in the horizontal direction, and the above-described problem of multiple reflection can be effectively suppressed. Therefore, as long as such a problem can be solved, various forms can be adopted as the shape of the bottom surface of each separation groove. For example, a sawtooth shape, a single slope shape, a curved surface shape, or the like can be adopted. However, if the same backing material is used in the upper layer portion 150A and the lower layer portion 150B and the reflection of ultrasonic waves at their boundary surfaces is substantially negligible, the bottom surface of each notch groove is a horizontal plane. It is also possible.

  15 and 16 show a method of manufacturing the backing member shown in FIG. As shown in FIG. 15, a plurality of cutout grooves 164 are formed in the backing block 160. In this case, by appropriately selecting the shape of the blade used in the dicing saw, it is possible to realize a groove shape protruding downward between the adjacent protruding walls 166. Reference numeral 161 represents a substrate, and reference numeral 162 represents a backing body.

  After the plurality of notches 164 are formed, they are filled with a backing material 172. This is shown in FIG. Thus, a backing member 170 is configured, and the backing member 170 corresponds to the backing member 150 shown in FIG.

  Next, a modified example of the substrate will be described with reference to FIGS. A substrate 180 shown in FIG. 17 has a lead pattern 182 including a plurality of leads 184. Each lead 184 includes a lead main body 186 and a wide upper end 188 formed on the upper end side thereof. Incidentally, reference numeral 190 represents a relay portion connecting the lead main body 186 and the wide upper end 188, which has a tapered shape.

  FIG. 18 shows still another modified example of the substrate, and the substrate 192 has a lead pattern 194 as shown in the drawing. That is, each lead 196 has a lead body 198 and a portion 202 corresponding to the wide upper end, but the wide upper end 202 is connected to each other, and constitutes the upper end connecting portion 200 as a whole. . Use of the substrate 180 shown in FIG. 17 and the substrate 192 shown in FIG. 18 has an advantage that the upper end arrangement can be made appropriate even when a substrate positioning error occurs, as will be described below. This will be described.

  FIG. 19 shows a schematic view of the backing member as viewed from above. Three substrates 180A, 180B and 180C corresponding to the substrate 180 shown in FIG. 17 are provided in the backing member. The respective substrates 180A, 180B, and 180C are inconsistent in position. In such a state, when the plurality of cutout grooves 204 are formed, partial remaining occurs in any of the plurality of wide upper end portions 188A, 188B, 188C, that is, the lead upper end elements 188Aa, 188Ba, 188Ca with that portion. Can be configured.

  In other words, in this state, as shown in FIG. 20, the lead 184 includes a lead body 186, a relay element 190, and a portion (lead upper end element) 188a left in the wide upper end 188. That is, the lead upper end element 188a that is electrically connected to the vibration element can be reliably connected to the lead body 186. Even in this case, an electrical short circuit or the like does not occur between adjacent leads. Incidentally, reference numeral 206 represents the depth of the cutout groove, and reference numeral 208 represents the maximum depth of the widened portion. The difference between them is an area where the relay element 190 exists, and the relay element 190 makes electrical connection between the lead upper end element 188a and the lead body 186 as described above. Reference numeral 209 denotes a backing material filled in a notch groove formed in the backing member. Reference numeral 180 </ b> A represents an upper layer portion of the substrate 180, and reference numeral 180 </ b> B represents a lower layer portion of the substrate 180.

  In the above, the operation of the substrate 180 shown in FIG. 17 has been described, but the same operation as described above can be obtained for the substrate 192 shown in FIG. That is, the above-described upper end connecting portion 200 is separated into portions for each lead by forming a plurality of cutout grooves.

  Next, another method for manufacturing the plurality of protrusions will be described with reference to FIGS. A plurality of cavities 214 are formed in the upper end 212 of the substrate 210. Each cavity 214 is provided between two adjacent leads 215. Each cavity 214 is a closed cavity, and a communication part 218 exists above the cavity. That is, the protrusions 216 are connected to each other at the upper end portion, and their arrangement is maintained.

  The cavity 214 can be easily manufactured by, for example, laser processing, etching processing, punching processing, or the like. When the backing block is manufactured using the substrate 210, various methods as shown in FIGS. 9 to 12 can be used. In that case, the backing material 220 may be filled in each of the cavities 214 at the stage of manufacturing the backing block, or the backing material 220 may be provided for each of the cavities 214 for each substrate 210 before the backing block is manufactured. May be filled. In any case, after the backing block is completed, the upper edge portion thereof is cut. Specifically, when attention is paid to each substrate 210, the upper edge is removed as indicated by reference numeral 222, As a result, a backing member similar to the backing member as shown in FIGS. 4 and 7 can be obtained. That is, according to the method shown in FIG. 21, it is not necessary to form a plurality of cutout grooves after the backing block is manufactured.

  As described with reference to FIGS. 13 and 14, when the reflection of ultrasonic waves in the vertical direction in the backing member becomes a problem, it is desirable to use a substrate 230 as shown in FIG. In the substrate 230, the lead pattern 232 is composed of a plurality of leads 234, and a cavity 236 is formed between adjacent leads, and finally, a backing material 240 is filled therein. The lower end portion of each hollow portion 236 has a triangular shape protruding downward, that is, the boundary surface (boundary side) 238 is constituted by two inclined surfaces. After the backing block is formed using the plurality of substrates 230, the upper edge thereof is removed as indicated by reference numeral 242, thereby forming a backing member similar to the backing member as shown in FIG. 14 or FIG. It becomes possible.

  As described above, according to the backing member of this embodiment, the problem of reflection of ultrasonic waves and propagation of ultrasonic waves by a plurality of substrates can be effectively prevented or reduced. In addition, the directivity can be improved. In particular, since uniform image quality can be obtained with the tomographic image in the X direction and the tomographic image in the Y direction, a beneficial effect can also be obtained in disease diagnosis. As a method for forming the protrusion array on the upper layer portion of the backing member, it is desirable to use the above-described method, but other methods can be employed. For example, by arranging a plurality of linear members (conductors) on the upper edge of the substrate in a comb-like shape and aligning a plurality of such substrates, a plurality of protrusion arrays are constructed in the upper layer portion of the backing member. It may be. According to such a configuration, unnecessary portions of the substrate as described above can be excluded from the upper layer portion without forming a plurality of cutout grooves. Although the 2D array transducer has been described in the above embodiment, the present invention can be applied to a 1.5D array transducer or the like. That is, the present invention can be widely applied to an ultrasonic transducer in which a plurality of substrates are embedded in a backing member. Although it is desirable to use FPC as the substrate, other substrates may be used. Further, the end of each board on the cable side may be pulled out from the backing member so that the signal lines can be connected more easily.

It is a figure which shows the prior art example of a backing member. It is a figure which shows the prior art example of a vibrator | oscillator assembly. It is a figure for demonstrating the problem of the reflection and propagation of an ultrasonic wave in a prior art example. It is a figure which shows the vibrator | oscillator assembly which concerns on this embodiment. It is a figure which shows the board | substrate which concerns on this embodiment. It is a figure which shows the some notch groove formed with respect to a backing block. It is a figure which shows the backing member manufactured by filling the backing material with respect to a some notch groove. It is a flowchart which shows the manufacturing method of the ultrasonic probe which concerns on this embodiment. It is a figure which shows the manufacturing method of the backing block by the adhesion method. It is a figure which shows the manufacturing method of the backing block by a board | substrate insertion method. It is a figure which shows the manufacturing method of the backing block using a some flame | frame. It is a figure which shows the manufacturing method of the backing block by the filling of the backing material in a formwork. It is a figure for demonstrating the problem of the reflection of the ultrasonic wave in a backing member. It is a figure for demonstrating the principle which prevents reflection of the ultrasonic wave in a backing member. It is a figure which shows the some notch groove formed in the backing block. It is a figure which shows the backing member manufactured by filling the backing material with respect to a some notch groove. It is a figure which shows the 1st modification of a board | substrate. It is a figure which shows the 2nd modification of a board | substrate. It is a figure for demonstrating the advantage at the time of using the board | substrate shown in FIG. It is a figure for demonstrating the advantage at the time of using the board | substrate shown in FIG. It is a figure which shows an example of the board | substrate which has a some cavity part. It is a figure which shows the other example of the board | substrate which has a some cavity part.

Explanation of symbols

  52 backing member, 54 vibrating element array, 56 matching element array, 58 vibrating element, 59 signal electrode, 60, 66 separation groove, 72 substrate, 73 backing body, 74 base layer, 76 lead, 80 notch, 82 protrusion.

Claims (17)

An array vibrator composed of a plurality of vibration elements;
A backing member provided below the array transducer and having a plurality of substrates electrically connected to the array transducer;
Including
Each of the substrates has a base layer and a plurality of leads provided in the base layer,
A plurality of protrusions protruding toward the array transducer side and a plurality of notches are alternately formed on the upper end of each substrate.
Each protrusion has a lead protrusion element;
The ultrasonic probe according to claim 1, wherein the upper layer portion of the backing member is composed of a backing material and a protrusion array embedded in the backing material. The ultrasonic probe according to claim 1,
The width of each notch is larger than the width of each separation groove formed between the vibration elements in the array transducer. The ultrasonic probe according to claim 2,
The depth of each said notch part is larger than the penetration depth in the said backing member in each said separation groove, The ultrasonic probe characterized by the above-mentioned. The ultrasonic probe according to claim 1,
The amount of protrusion of each protrusion is at least twice the wavelength of the ultrasonic wave transmitted and received by the array transducer. The ultrasonic probe according to claim 1,
Each of the projecting portions includes a base layer projecting element having an elongated shape and the lead projecting element having an elongated shape. The ultrasonic probe according to claim 1,
Each lead is
The lead projecting element;
A lead relay element provided on the lower end side of the lead projecting element and extending in the horizontal direction;
A lead body element electrically connected to the lead projecting element via the lead relay element;
Ultrasonic probe characterized by comprising. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein each of the substrates is a flexible circuit board. An array transducer composed of a plurality of transducer elements arranged on a plane defined by the X direction and the Y direction;
A member that is provided below the array transducer and attenuates ultrasonic waves radiated rearward from the array transducer, and is a plurality of components arranged in the X direction that are electrically connected to the array transducer. A backing member having a substrate;
Including
In the upper layer portion of the backing member, a plurality of cutout grooves arranged in the Y direction and extending in the X direction are formed, whereby a plurality of protrusions are formed at the upper end of each substrate,
Each protruding portion has a lead protruding element while protruding toward the array transducer side,
The ultrasonic probe according to claim 1, wherein a backing material is filled in each of the cutout grooves, whereby a space between adjacent protrusions in the backing member is filled with the backing member. The ultrasonic probe according to claim 8,
The ultrasonic probe according to claim 1, wherein a bottom surface of each notch groove is flat. The ultrasonic probe according to claim 8,
2. The ultrasonic probe according to claim 1, wherein a bottom surface of each notch groove is composed of one or a plurality of inclined surfaces. The ultrasonic probe according to claim 8,
2. The ultrasonic probe according to claim 1, wherein the backing material filled in each notch groove is substantially the same as the backing material constituting the backing body of the backing member. The ultrasonic probe according to claim 8,
The ultrasonic probe according to claim 1, wherein the width in the Y direction of the upper end of each protrusion is defined by the interval between two cutout grooves passing through both sides thereof. Producing a backing member having a plurality of substrates;
Providing a plurality of vibration elements on the upper side of the backing member;
Providing a plurality of matching elements above the plurality of vibration elements;
Including
In the step of manufacturing the backing member, a plurality of protrusions are formed at the upper end of each substrate,
Each protrusion has a lead protrusion element;
In the step of providing the plurality of vibration elements, a plurality of lead projecting element end faces exposed on the upper surface of the backing member are electrically connected to the plurality of vibration elements.
An ultrasonic probe manufacturing method characterized by the above. The manufacturing method according to claim 13, wherein
The step of manufacturing the backing member includes:
Producing a backing block using the plurality of substrates;
Forming a plurality of cutout grooves in the backing block, thereby forming the plurality of protrusions at the upper end of each substrate;
Filling the plurality of notch grooves with a backing material;
A method for manufacturing an ultrasonic probe, comprising: The manufacturing method according to claim 13, wherein
The step of manufacturing the backing member includes:
Producing a plurality of processed substrates in which a plurality of cavities are formed between leads at the upper end as the plurality of substrates;
A step of manufacturing a backing block using the plurality of processed substrates while filling each cavity with a backing member;
Removing the upper edge of the backing block and forming the plurality of protrusions on the upper edge of each processed substrate;
A method for manufacturing an ultrasonic probe, comprising: The manufacturing method according to claim 13, wherein
The step of manufacturing the backing member includes:
Producing a plurality of processed substrates in which a plurality of cavities are formed between leads at the upper end as the plurality of substrates;
Filling each cavity with a backing member, then removing the upper edge of each processed substrate and forming the plurality of protrusions on the upper end of each processed substrate;
Using the plurality of processed substrates formed with the plurality of protrusions to produce the backing member;
A method for manufacturing an ultrasonic probe, comprising: The manufacturing method according to claim 14, wherein
Before the formation of the plurality of cutout grooves, the upper end of each lead in each substrate is formed wide,
The method of manufacturing an ultrasonic probe, wherein at the time of forming the plurality of cutout grooves, an upper end portion of each lead is partially removed and the lead projecting element remains.

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