JP5146815B2 - Ultrasonic probe, endoscope and method for manufacturing ultrasonic probe - Google Patents

Description

  The present invention relates to an ultrasonic probe that can be used for precise diagnosis and treatment of a local part of a living body, an endoscope including the same, and a method of manufacturing the ultrasonic probe.

  In endovascular treatment using an endoscope, if the blood vessel is narrowed and the lumen is biased, or if the blood vessel is curved and it is difficult to pass through the endoscope, the catheter can be used inside the blood vessel without damaging the lesion. A forward-viewing ultrasonic endoscope that can safely observe the shape of the front of the device has been developed.

  In particular, for chronic total occlusion lesions, when the blood vessel is completely occluded due to thrombus or cholesterol, etc., the recanalization treatment is performed using a hard guide wire, so the guide wire can be safely used without puncturing the blood vessel. There is a need for an intravascular front-view ultrasound endoscope capable of observing in front three-dimensional and real-time the blood vessel structure into which a catheter is to be inserted in advance in order to push it forward. For this reason, the present inventors have already succeeded in trial production of a forward-viewing ultrasonic endoscope. For example, a front-view ultrasound endoscope can be manufactured in a lump by using a conductive backing (Patent Document 1), and a convex vibrator that can control directivity (Patent Document 2) has also been successfully produced. In addition, non-planar lithography has also been developed as a basic technique for mounting a high-performance MEMS device on the catheter tip (Patent Document 3).

  Patent Document 4 discloses a technique in which minute piezoelectric elements are manually arranged and mounted on a catheter, and Patent Document 5 discloses an inner array that can be viewed forward by forming an element array on a flexible sheet and winding it around the catheter. An endoscope is disclosed, and Non-Patent Document 1 discloses a technique in which a multi-element piezoelectric element is attached to the distal end portion of a catheter.

Japanese Patent No. 3552923 Japanese Patent No. 3787725 JP 2007-114758 A JP 2000-358299 A US Pat. No. 6,457,365 IEEE Trans. Ultrason., Ferroselect. Freq. Contr., Vol. 51, (2004), pp. 800-808. IEEE Trans. Ultrason., Ferroelec. Freq. Contr., Vol. 44, (1997), pp. 1140-1147.

  However, in the forward-viewing ultrasonic endoscope developed by the present inventors, the number of ultrasonic transducers is small, causing a virtual image called an artifact. An artifact is a virtual image generated when an ultrasonic image is constructed, and should not be inherent. In addition, the techniques disclosed in Patent Documents 4 and 5 and Non-Patent Document 1 have a drawback that it is difficult to form a ring array and multiple elements with a free design, and it is difficult to take out wiring for each piezoelectric element and mount it on a catheter. is there.

  PMN-PT disclosed in Non-Patent Document 2 has excellent piezoelectric characteristics that can replace conventional PZT. However, PMN-PT is easily destroyed, and it is not possible to easily make an ultrasonic probe.

  A first object of the present invention is to provide an ultrasonic probe in which piezoelectric elements are arranged in a ring array to form a multi-element and an endoscope including the same.

  The second object of the present invention is to provide a method for producing an ultrasonic probe that can be easily produced even if piezoelectric elements are arranged in a ring array to form a multi-element.

  In order to achieve the first object, an ultrasonic probe of the present invention includes an ultrasonic transducer arranged in a ring array and vibration absorption arranged on the rear side of the ultrasonic transducer for each ultrasonic transducer. And a holding portion for holding each vibration absorber, and a wiring connection portion for each ultrasonic transducer is provided at the rear end portion of the holding portion. The back side electrode and the wiring connection part are electrically connected.

Preferably, a connection member is disposed on the rear side of the holding portion. In particular, the connecting member may be composed of one tube or a plurality of concentric tubes, or may be formed by deforming a flexible substrate or a flexible sheet into a tube shape.
Preferably, the connection member is provided with a wiring pattern including a connection electrode portion connected to the wiring connection portion, and circuit components for processing signals related to transmission and reception of ultrasonic waves by the ultrasonic transducer are mounted. Yes.
The wiring connection part can be circumferentially arranged with an interval between the outer peripheral edge part of the rear end part of the holding part.
The wiring connection portion may be arranged at the rear end portion of the holding portion along the same or similar arrangement pattern as the arrangement pattern of the ultrasonic transducers.
Preferably, the holding portion has a through-hole and has a truncated cone shape with the through-hole as an axis, and the wiring connection portion is arranged at a distance from the rear end surface or the side surface of the holding portion. Alternatively, the holding part has a through hole and has a stepped shape in which the width in the axial direction changes in the radial direction with the through hole as an axis, and the wiring connection part seems to be arranged at an interval on the rear end surface of the holding part. It may be.
The endoscope of the present invention is configured by mounting the ultrasonic probe of the present invention on a distal end portion of a catheter or an endoscopic tool.

  In order to achieve the second object described above, the ultrasonic probe manufacturing method of the present invention forms an embedded portion in a predetermined pattern on the back surface of the piezoelectric body with one or more circumferential intervals, A metal layer is formed for each part, a backing layer serving as a vibration absorber is injected into each buried part, and a wiring structure is formed on the backing layer, thereby forming a holding part in which the wiring structure and the backing layer are embedded. And dividing the piezoelectric body into a single or multiple ring array and forming a through hole in the piezoelectric body and the holding portion.

Furthermore, a wiring member is formed on the cylindrical member, or a wiring member is formed on a flexible sheet or flexible substrate and deformed into a tube shape to form a connecting member, and each back side in the wiring structure of the holding unit Connecting the electrode and each connection electrode portion of the wiring pattern.
When forming the holding portion, it is preferable to form a connection wiring portion corresponding to each backing layer at an interval on the outer peripheral edge of the rear end portion of the holding portion. When forming the holding portion, it is preferable to form a connection wiring portion along the arrangement pattern of the backing layer at the rear end portion of the holding portion. It is preferable to use nonplanar photolithography when forming the wiring structure.

  According to the ultrasonic probe of the present invention, since many ultrasonic transducers are provided, even if the ultrasonic vibration is generated and the reflection is received, the artifact is suppressed, and the echo image is accurately obtained from the received ultrasonic vibration. It can be obtained in three dimensions. Further, by providing a wiring structure, particularly a multilayer wiring structure, in the holding part, the back side electrode of the ultrasonic transducer can be drawn out to the back end part of the holding part by wiring. Thereby, electrical connection to the catheter tip can also be easily performed. Further, the holding portion is provided with wiring extending backward in a predetermined wiring pattern, and an IC chip in which a signal amplifier circuit, a signal switching circuit, and the like are integrated can be easily mounted.

  According to the method for manufacturing an ultrasonic probe according to the present invention, it is possible to manufacture an ultrasonic probe with high accuracy with few manual processes. Further, the multilayer wiring structure in the holding part can be easily and precisely manufactured by employing the non-planar photofabrication developed by the present inventors.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
An ultrasonic probe according to an embodiment of the present invention generates ultrasonic waves from one or a plurality of ultrasonic transducers arranged in a ring shape, and generates reflected waves of the generated ultrasonic waves. It can be received by a vibrator. Since this ultrasonic probe has a multi-element ultrasonic transducer, artifacts are suppressed, and an echo image can be obtained accurately and three-dimensionally from the received ultrasonic vibration. In the following embodiments, some preferred embodiments will be described, but the design can be appropriately changed in accordance with the gist of the present invention.

(First embodiment)
As a first embodiment of the present invention, a transmission / reception unit is configured by arranging ultrasonic transducers in a double ring shape, and a single tube is provided as a connection member for wiring extraction outside on the rear side of the transmission / reception unit. The provided form will be described.

FIG. 1 is a schematic view showing an endoscope to which an ultrasonic probe according to the first embodiment is attached.
The ultrasonic probe 1 according to the first embodiment is attached to the distal end portion 2 </ b> A of the catheter 2 and constitutes an endoscope 3. The ultrasonic probe 1 includes a transmission / reception unit 10 that transmits and receives ultrasonic vibrations, and a connection member 20 that is attached to the rear side of the transmission / reception unit 10. The transmission / reception unit 10 and the connection member 20 have a through hole 1 </ b> A that penetrates. The through hole 1A functions as a working channel of the endoscope 3, and the tube member 30 is inserted as necessary. The tube member 30 functions as a ground wiring, for example. The working channel serves as an inlet for necessary angiographic agents and drug solutions, and as an insertion path for micro tools such as a guide wire.

[Configuration of ultrasonic probe]
The ultrasonic probe 1 according to the first embodiment will be described in detail.
2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along the line BB in FIG. 1, and FIG. FIG. 5 is a cross-sectional view taken along the line CC, and FIG. 5 is a view of the transmission / reception unit 10 in the ultrasonic probe 1 as viewed from the rear.

  In the first embodiment, the transmission / reception unit 10 of the ultrasonic probe 1 includes a plurality of ultrasonic transducers 11 arranged in a ring array and each ultrasonic transducer 11 as shown in FIGS. A vibration absorber 12 that absorbs vibration and a holding portion 13 that holds the vibration absorber 12 are included. The holding unit 13 includes a multilayer wiring structure 13 </ b> A that makes electrical connection to the ultrasonic transducer 11.

  Each ultrasonic transducer | vibrator 11 is arrange | positioned at the ring array shape, and is isolate | separated by the space | gap or rod part as the isolation | separation part 11A. For example, as shown in FIG. 4, the ultrasonic transducer 11 is arranged so as to form a double ring array around the through hole 1 </ b> A. In the illustrated example, eight ultrasonic transducers 11 are arranged in the inner ring array and sixteen ultrasonic transducers 11 are arranged in the outer ring array. As a result, ultrasonic waves can be transmitted from one ultrasonic transducer 11, and the reflected waves of the transmitted vibrations can be received by a plurality of ultrasonic transducers 11, that is, 24 pieces. Further, ultrasonic waves can be transmitted from any plural or all of the ultrasonic transducers 11 and received by all or some of the ultrasonic transducers 11.

  The ultrasonic transducer 11 is configured by sandwiching a segmented piezoelectric body 11B between a front side electrode 11C and a back side electrode 11D. In addition to PZT, it is preferable to use piezoelectric single crystal PMN-PT (magnesium magnesium niobate titanate), which has excellent piezoelectric characteristics and an acoustic impedance close to that of a living body, in addition to PZT. In the illustrated example, the front electrode 11C is not divided for each ultrasonic transducer but is a common electrode, but may be subdivided for each ultrasonic transducer. A matching layer 14 is formed on the front electrode 11C. The matching layer 14 is for impedance matching between the ultrasonic transducer 11 and a medium such as a liquid existing in a space where the ultrasonic probe 1 is used.

  The holding unit 13 includes an embedded unit 13B in which the same number of vibration absorbers 12 as the ultrasonic transducers 11 are embedded, and a multilayer wiring structure 13A. The same number of wiring connection portions 16 as the ultrasonic transducers 11 are provided on the rear surface of the holding portion 13. In the multilayer wiring structure 13A, the back electrode 11D and the wiring connection portion 16 are electrically connected to each other.

  The embedding part 13 </ b> B has a plurality of embedding parts on the back side of the ultrasonic transducer 11 following the arrangement of the ultrasonic transducer 11. The number of embedding parts 13 </ b> B provided in the holding part 13 is the same as that of the ultrasonic transducers 11. As the material of the embedded portion 13B, a thick film photoresist that can be easily formed in a three-dimensional shape can be employed. The vibration absorbers 12 are embedded and held in the embedded portions 13B. The embedded portion 13B is configured by connecting a plurality of ring portions with branch portions extending in the radial direction. An epoxy resin mixed with tungsten powder can be used for the vibration absorber 12. The vibration absorber 12 instantaneously absorbs the vibration of the ultrasonic vibrator 11 accompanying the transmission of the ultrasonic wave from the ultrasonic vibrator 11, thereby generating noise in the ultrasonic signal received by the ultrasonic vibrator 11. I won't let you.

  The multilayer wiring structure 13A electrically connects the back-side electrode 11D provided on the back surface of each ultrasonic transducer 11 and the wiring connection portion 16 respectively. The front side of the embedded portion 13B corresponds to the back surface of the ultrasonic transducer 11. The multilayer wiring structure 13A is attached to the back side electrode 11D of the ultrasonic transducer 11, the metal layer 13C attached to at least one side wall of each embedded part 13B, and the back side electrode 11D of the vibration absorber 12 on the opposite side. The metal layer 13D, the interlayer insulating films 13E and 13G that connect the metal layer 13D and the wiring connection portion 16, and the buried electrode portions 13F and 13H. In this multilayer wiring structure 13A, each back-side electrode 11D and each wiring connection portion 16 are connected by wiring.

  For example, as shown in FIG. 5, the wiring connection portions 16 are arranged in the same number as the ultrasonic transducers 11 with a gap in the circumferential edge of the cylindrical holding portion 13. The wiring connection portion 16 includes a first wiring connection portion 16A that is wired to each of the ultrasonic transducers 11 in the outer ring array shape, and a second wiring connection that is connected to each of the ultrasonic transducers 11 in the inner ring array shape. Wiring connection portion 16B. In the example shown in FIGS. 4 and 5, sixteen ultrasonic transducers 11 are arranged on the outer side, and eight ultrasonic transducers 11 are arranged on the inner side. In the arrangement pattern, one second wiring connection portion 16B is arranged every two first wiring connection portions 16A.

Next, the connection member 20 will be described.
6 is a diagram schematically showing the connecting member 20, FIG. 7 is a sectional view taken along the line DD in FIG. 1, and FIG. 8 is a sectional view taken along the line EE in FIG.
As shown in FIG. 8, the connection member 20 forms a multilayer wiring as shown in FIG. 8 with an insulating layer 22 made of resin and an electrode layer 23 made of Cu on the outer peripheral portion of an insulating tube 21 such as a glass tube. As the resin, a paraxylylene resin can be used. In the electrode layer 23, a connection electrode portion 23 </ b> A is formed on the side connected to the transmission / reception unit 10, and the connection electrode portion 23 </ b> A is electrically connected to the wiring connection portion 16. The multilayer wiring is formed in a laminated structure of an electrode layer 23 and an insulating layer 22 having a predetermined pattern formed on the insulating tube 21. An IC chip 24 as a circuit component is connected on the electrode layer 23 of the multilayer wiring of the connection member 20. As shown in FIG. 7, a plurality of IC chips 24 are arranged on the multilayer wiring, for example, at the outer peripheral portion of the connection member 20 at equal intervals when viewed from the central axis of the connection member 20. This is because the ultrasonic probe 1 has a minute size that can be inserted into a blood vessel. A wiring such as a coaxial cable disposed from the rear end portion of the catheter 2 to the distal end portion 2A of the catheter 2 is electrically connected to the multilayer wiring.

  FIG. 9 is a development view showing an example of a wiring pattern formed on the connection member 20. As shown in FIG. 9, the wiring pattern formed on the connecting member 20 is arranged in the axial direction of the first connecting electrode portion 23 </ b> A disposed on the outer periphery of the insulating tube 21 on the transmission / reception unit 10 side. The second connection electrode portion 23B, and the wiring connection portion 23C that connects the first connection electrode portion 23A and the second connection electrode portion 23B. The first connecting electrode portion 23A has an area connectable with the wiring connecting portion 16, and the second connecting electrode portion 23B has an area connectable with the IC chip 24 and the wire. The wiring connecting portion 23C is formed in a linear shape.

  In the ultrasonic probe 1 according to the first embodiment, when an electrical signal is input to the IC chip 24 via a wiring such as a coaxial cable, the ultrasonic wave in the transmission / reception unit 10 is received by the IC chip 24 based on the input. A voltage is applied to at least one specific ultrasonic transducer 11 in the transducer group. Then, the specific ultrasonic transducer 11 generates ultrasonic waves. Thereafter, the IC chip 24 receives an electrical signal obtained by converting the ultrasonic vibration received by each ultrasonic transducer 11 of the ultrasonic transducer group in the transmission / reception unit 10, performs predetermined signal processing, and performs signal processing on the coaxial cable. Is output.

  The ultrasonic probe 1 according to the first embodiment employs a so-called phased array method in which all of the ultrasonic transducer groups in the transmission / reception unit 10 are phase-driven and reception of ultrasonic echoes from the object to be measured is also phase-driven. You may send and receive.

  In addition to the above-described transmission and reception modes of ultrasonic waves by the ultrasonic probe 1, light may be emitted from the working channel in a pulse manner at a frequency of ultrasonic vibration, and reflection may be received by the ultrasonic probe 1. .

  At that time, the number of ultrasonic transducers 11 of the ultrasonic probe 1 is increased, and the frequency of ultrasonic vibration is increased, thereby reducing artifacts. In addition, since the signal processing is performed by the IC chip 24 directly below the ultrasonic transducer 11, signal deterioration due to transmission / reception with the outside via the coaxial cable does not occur. Therefore, even with the small ultrasonic probe 1, the resolution of the image can be increased.

[Method of manufacturing ultrasonic probe]
Hereinafter, a method for manufacturing the ultrasonic probe 1 according to Embodiment 1 will be described.
In the ultrasonic probe 1, the transmitting / receiving unit 10 and the connecting member 20 are respectively produced, and the wiring connecting unit 16 in the transmitting / receiving unit 10 and the first connecting electrode unit 23A in the connecting member 20 are connected by bonding, soldering, or the like. Thus, it can be manufactured.

The manufacturing process of the transmission / reception unit 10 is as follows. FIG. 10 is a diagram showing the first half of the manufacturing process of the transmitting / receiving unit 10 in the ultrasonic probe 1, and FIG. 11 is a diagram showing the middle stage of the manufacturing process of the transmitting / receiving unit 10 in the ultrasonic probe 1. FIG. 12 is a diagram illustrating the latter half of the manufacturing process of the transmission / reception unit in the ultrasonic probe. In this step, a plurality of patterns may be formed on the piezoelectric body 40 as a single substrate, and a plurality of transmission / reception units 10 may be manufactured collectively.
First, one surface, for example, the negative surface of the prepared piezoelectric body 40 is polished (FIG. 10A), a resist 41 is applied, and a pattern is formed by photolithography to form an embedded portion 41A (FIG. 10). (B)). The resist may be formed by attaching a dry film resist instead of coating.

  Next, a metal layer 42 is formed on the bottom and side walls of the embedded portion 41A. At this time, even if a layer such as Au (gold) that directly forms the metal layer 42 is formed on the piezoelectric body 40 in advance, it is easy to peel off. Therefore, as shown in FIG. 10C, Ti (titanium), Mo (molybdenum) ), A base layer 42A such as Cr (chromium) is formed, and then a seed metal layer is formed thereon, and the metal layer 42B is thickened by electrolytic plating (FIG. 10D). For the formation of the underlayer 42A, a thin film forming method such as sputtering or vacuum vapor deposition can be employed. Note that the metal layer 42 formed on the bottom and side walls of the embedded portion 41A becomes part of the back electrode 11D and the metal layer 13C of the ultrasonic transducer 11.

  Next, the embedded portion 41A is filled with a backing material 43A serving as a vibration absorber (FIG. 10E), and the unnecessary backing material is removed to form the backing layer 43 (FIG. 10F). At this time, the metal layer between the embedded portions is removed by polishing or the like. This backing layer 43 becomes the vibration absorber 12.

Next, a metal layer 44 is formed on the entire surface with respect to the polished surface (FIG. 10G), and a resist is formed by photolithography as an etching mask 45 for the metal layer 44 (FIG. 11A). The electrode layer 44A is patterned by etching 44 (FIG. 11B), and after completion, the resist as the etching mask 45 is removed with an organic solvent such as acetone (FIG. 11C).
Next, photosensitive polyimide is formed as the insulating layer 46, and patterning is performed by photolithography (FIG. 11D). After forming the metal layer 47 on the polished surface (FIG. 11E), the metal layer 47 is formed. The etching mask 48 is formed by resist photolithography (FIG. 11F).
Next, after etching the metal layer 47 and patterning the electrode 47A (FIG. 11G), the resist as the etching mask 48 is removed with an organic solvent such as acetone (FIG. 12A).

Next, the piezoelectric body 40 is polished to a predetermined thickness to obtain a piezoelectric body 40A (FIG. 12B). Thereby, mode resonance of several tens, for example, 20 MHz becomes possible.
Next, a sandblast etching mask 49 is produced by photolithography of an etching resist for sandblasting (FIG. 12C).
The groove 50 is formed in the piezoelectric body 40A using sandblasting, and patterning is performed in a ring array shape so as to form a plurality of elements, and the through holes 51 are formed (FIG. 12D), and the resist is removed (FIG. 12). (E)).
Next, the groove 50 formed by patterning in the piezoelectric body 40A is filled with a filler to form a separation portion 52 (FIG. 12F), and the front electrode 53 is formed on the piezoelectric body 40A (FIG. 12G). )), And the matching layer 14 is further formed as necessary to complete the transmission / reception unit 10. The formation of the front electrode 53 and the matching layer 14, the extraction of the ground, and the separation of the transmission / reception unit 10 can be performed by appropriately changing processes.

A method for producing the connection member 20 will be described.
FIG. 13 is a diagram illustrating a manufacturing process of the connection member 20. An insulating tube 60 such as a glass tube or an insulating tube 60 obtained by subjecting the surface of a metal tube or the like to insulation treatment is prepared as a substrate for the connecting member 20 (FIG. 13A).
Next, a base layer 61A in which Ti (titanium) and Au (gold) are sequentially laminated is formed on the entire side surface of the insulating tube 60 (FIG. 13B). The Ti layer is a layer inserted in order to improve adhesion with the insulating tube 60. The adhesion may be enhanced by a Mo (molybdenum) layer or a Cr (chromium) layer instead of the Ti layer. For the formation of the underlying layer 61A, a thin film forming method such as sputtering can be used.
A resist 62 is applied to the entire surface of the base layer 61A (FIG. 13C), mask exposure is performed using a laser or the like, and development is performed to pattern the resist 62A (FIG. 13D).
A plating layer is formed on the base layer 61A using an electrolytic plating method or the like to increase the overall thickness to form a metal layer 61B (FIG. 13E), and the resist 62A is removed with an organic solvent (FIG. 13F). ), The exposed portion of the base layer 61A is removed by etching, and only the wiring portion 61C is formed in the insulating tube 60 (FIG. 13G).
Thereafter, the edge of the connection electrode part for connecting the IC chip and the wire is formed by dicing as shown by a dotted line (FIG. 13H), and the connection member 20 is obtained.
In the above manufacturing process, when lithography is performed on a non-planar surface, non-planar photolithography, that is, the resist height position and film thickness distribution are decomposed into a two-dimensional matrix, and the exposure height for each matrix without using a photomask. It is possible to use a method of performing exposure using an exposure dose amount that matches the height of the focus and the resist thickness (see Patent Document 3).

  FIG. 14 is a schematic view showing another connecting member 20 ′. The connecting member 20 may have a cylindrical cross section, an elliptical shape having a hollow shape, or a flat shape having a hollow shape, and may have a hollow triangular shape as shown in FIG. It may be square. A wiring pattern as indicated by reference numeral 61C is formed on the connecting member 20 'shown in FIG. Thus, instead of the insulating tube 60, wiring patterns may be formed on a substrate having various cross-sectional shapes.

  FIG. 15 is a diagram illustrating a manufacturing process of the connection member 20 different from that in FIG. 13. Unlike the process shown in FIG. 13, a wiring pattern may be formed on the flexible substrate 20A (FIG. 15A), and then the flexible substrate 20A may be deformed into a tube shape to form the connection member 20B (FIG. 15B). ). The connection member 20B may have a circular, elliptical, or flat cross section, or a polygonal shape such as a triangular shape or a rectangular shape. If the flexible substrate 20A is rounded to form a cylindrical shape, even if the end faces parallel to the axis are joined as shown in FIG. 15B, the end faces parallel to the axis are joined together. There may be no case. A flexible sheet may be used instead of the flexible substrate 20A.

A connection method between the transmission / reception unit 10 and the connection member 20 will be described.
FIG. 16 is a diagram illustrating a connection process between the transmission / reception unit 10 and the connection member 20.
The connecting member 20 is formed with a multilayer wiring by the electrode layer 23 on the surface of the cylindrical insulating tube, that is, the outer peripheral portion (see FIG. 16A). The insulating tube 21 has a shaft portion 21 </ b> A that communicates with the through hole 1 </ b> A of the transmission / reception unit 10 at the center thereof. In addition to the cylindrical glass tube, the insulating tube 21 may be a metal tube formed with an insulating film. The surface of the shaft portion of the insulating tube 21 may be covered with a conductive material to form a ground region (ground).

The tube member 30 is inserted into the through-hole 1A of the transmission / reception unit 10 manufactured as described above, and the tube member 30 is inserted into the shaft portion 21A of the insulating tube 21 (FIG. 16B). In this case, the outer peripheral surface of the tube member 30 may be covered with a conductive material to form a grounding region, that is, a ground.
Next, the wiring connection part 16 of the multilayer wiring structure 13A and the wiring part 23 on the insulating tube 21 are connected by the connection part 23D. In this connection step, the wiring connection portion 16 (not shown in FIG. 16) and a part of the wiring portion 23 are connected by solder or conductive resin. When connecting with solder, the solder may be melted and solidified by laser irradiation (FIGS. 16C and 16D).
Thereafter, an IC chip 24 (not shown in FIG. 16) is connected to the wiring portion 23 to complete the ultrasonic probe 1.

Since the ultrasonic probe 1 can be manufactured through the above steps, the endoscope 3 is completed by attaching the ultrasonic probe 1 to the distal end portion 2A of the catheter 2 as shown in FIG. Instead of the catheter 2, it may be attached to the tip of various endoscope tools. Here, the endoscope tool is an elongated tool that is inserted into a forceps port of an optical endoscope such as a fiberscope or an electronic endoscope, and is used for various diagnoses and treatments in the body.
In the first embodiment, the ultrasonic transducers are arranged in a double ring array, and the wiring connection portion of the transmission / reception unit is arranged circumferentially on the outer peripheral edge of the holding unit. The ring array of the ultrasonic transducer does not need to be double, and may be single or triple depending on the size of the ultrasonic transducer.

(Second Embodiment)
A second embodiment will be described.
In the second embodiment, the wiring connection portion of the transmission / reception unit is not arranged circumferentially on the outer peripheral edge as in the first embodiment, but is the same or similar to the arrangement pattern of the ultrasonic transducers. It arrange | positions at the rear-end part of a holding | maintenance part along the pattern.
In the following explanation, a case where ultrasonic transducers are arranged in a triple ring array and arranged in a triple ring array along the arrangement pattern of each ultrasonic transducer on the back side will be described. The arrangement of the acoustic wave vibrator and the wiring connection portion is not necessarily triple, and may be double or quadruple.

FIG. 17 is a diagram illustrating a connection method between the transmission / reception unit 70 and the connection member 80 in the ultrasonic probe 5 according to the second embodiment.
In the second embodiment, ultrasonic transducers are arranged in the transmitter / receiver 70 in a triple ring array. Corresponding to this arrangement, wiring connection portions 71 are arranged in a triple ring array on the back side of the transmission / reception unit 70. For example, when twelve ultrasonic transducers are arranged in the outer ring array, eight in the middle ring array, and four in the inner ring array, as shown in FIG. Twelve connection portions 71 are arranged in the outer ring array, eight in the middle ring array, and four in the inner ring array. Each wiring connection portion 71 is performed up to the step of providing the metal layer 44A immediately after the backing layer 43 forming the vibration absorber in the manufacturing method in the first embodiment (FIGS. 10A to 11C), After that, as shown in FIG. 12B in the first embodiment, the piezoelectric body 40 is polished to a predetermined thickness to obtain the piezoelectric body 40A, and the subsequent steps are performed in the same manner, so that the transmission / reception unit is manufactured. be able to.

  In the second embodiment, the connection member 80 is configured by coaxially arranging a plurality of tubes 81, 82, 83 having different diameters. In the case shown in FIG. 17, since the wiring connection portions 71 are arranged in a triple ring array, the connection member 80 has three tubes 81, 82, 83 of the same number as the array of the wiring connection portions 71 coaxially. Arranged and configured. A predetermined wiring pattern is formed on the outer peripheral surfaces of the tubes 81, 82, and 83 as in the first embodiment. Here, the polymer tube itself can be used as the thin-walled tubes 81, 82, 83, or the flexible sheet can be deformed. As the polymer tube, for example, a polyimide tube can be used. When the flexible sheet is rolled and deformed, the cross sections of the tubes 81, 82, and 83 may be circular, elliptical, flat, or polygonal shapes such as a triangular shape and a rectangular shape. As long as the flexible sheet is rolled up to have a cylindrical shape, not only the end faces parallel to the axis are joined but the end faces parallel to the axis may not be joined.

The connection between the transmission / reception unit 70 and the connection member 80 will be described with reference to FIG.
First, as shown in FIG. 17A, the first tube 81 is arranged behind the transmission / reception unit 70 so as to be coaxial with the through hole of the transmission / reception unit 70. Thereafter, each of the connection electrode portions 81 </ b> A provided on the outer periphery of the distal end portion of the first tube 81 is connected to each of the four wiring connection portions 71 </ b> A disposed on the innermost side on the back side of the transmission / reception unit 70. This connection can be performed in the same manner as in the first embodiment.

  Next, as shown in FIG. 17B, the second tube 82 is coaxially disposed outside the first tube 81. Thereafter, each of the connection electrode portions 82A provided on the outer periphery of the distal end portion of the second tube 82 is connected to each of the eight wiring connection portions 71B provided at a substantially intermediate position on the back side of the transmission / reception portion 70. Since wiring is formed behind the connection electrode portion 82A on the outer peripheral side surface of the second tube 82, an IC chip 82C as a circuit component is mounted on the IC connection electrode portion 82B. Further, each cable 82E is connected to each rear end electrode portion 82D of the wiring portion patterned on the outer peripheral surface of the second tube 82. Only a part of the wiring pattern is shown. The connection of the cable 82E to the tube 82 and the mounting of the IC chip 82C may be performed before or after the connection between the transmission / reception unit 70 and the tube 82.

  Next, as shown in FIG. 17C, the third tube 83 is coaxially disposed outside the second tube 82. Thereafter, each of the connection electrode portions 83 </ b> A provided on the outer periphery of the distal end portion of the third tube 83 is connected to each of the twelve wiring connection portions 71 </ b> C provided in the vicinity of the outer periphery of the transmission / reception unit 70. Since a wiring pattern is formed on the outer peripheral surface of the third tube 83 behind the connection electrode portion 83A, an IC chip 83C as a circuit component is mounted on the IC connection electrode portion 83B. Further, each cable 83E is connected to each rear end electrode portion 83D of the wiring portion patterned on the outer peripheral surface of the third tube 83.

  Next, as shown in FIG. 17D, the cable 81E is connected to the rear end electrode portion 81D of the wiring portion patterned on the outer peripheral surface of the first tube 81. At that time, an IC chip 81F may be interposed as shown.

  Through the above steps, the transmission / reception unit 70 and the connection member 80 are connected, and the wiring connection units 71A, 71B, 71C in the transmission / reception unit 70 are electrically wired toward the rear end of the connection member 80. IC chips 82C, 83C and 81F can be mounted. For example, signal switching circuits, signal amplifiers, and pulse generators are dispersedly arranged in the IC chips 81F, 82C, and 83C mounted on the first to third tubes 81, 82, and 83 forming the connection member 80, respectively. Is done. Thereby, each ultrasonic transducer | vibrator can be vibrated in order for a short time according to the operation signal input with respect to the ultrasonic probe 5 from the outside. Further, since the ultrasonic wave transmitted from the ultrasonic probe 5 is reflected by the subject, the ultrasonic probe 5 receives the reflected wave. Then, each ultrasonic transducer receives the reflected wave and converts it into an electrical signal. The electric signals converted by the respective ultrasonic transducers can be amplified by the IC chips 81F, 82C, 83C, and the respective ultrasonic signals can be output while being switched to the outside. Note that a ground wiring cable (not shown) may be inserted into the first tube 81 in advance in the step shown in FIG.

(Third embodiment)
Next, a third embodiment will be described.
The third embodiment is different from the first embodiment in the configuration of the holding unit. FIG. 18 is a schematic perspective view showing the holding portion 33 in the third embodiment. The holding part 33 has a through-hole 33A at its central axis, and has a cylindrical part 33B that directly holds a backing layer (not shown) and a frustoconical part 35 on the rear side. A wiring connection portion 36 is disposed on the side surface portion 35 </ b> A or the rear end portion 35 </ b> B of the truncated cone shape portion 35. In the illustrated case, the wiring connection portions 36 are arranged in two rows in the direction along the axis of the side surface portion 35A. In the case shown in the figure, the holding portion 33 is configured by two steps of the cylindrical portion 33B and the truncated cone-shaped portion 35, but may have three or more steps.

  FIG. 19 is a schematic perspective view showing a modified example of the holding portion 33 in the third embodiment. As shown in FIG. 19, the holding portion 33 has a through hole 33A on the central axis thereof, has a step shape in which the width in the axial direction changes along the radial direction with the through hole 33A as an axis, and the wiring connecting portion 36 Are arranged on the respective rear end surfaces 37A, 37B, 37C of the holding portion 33 with a space therebetween. That is, the holding part 33 is configured by a stepped cylindrical part. In the drawing, the holding portion 33 constituting the step cylindrical portion has a longer axial width on the through hole 33A side than on the radially outer side, but conversely, the through hole 33A side is on the radially outer side. The axial width may be shorter than that. Wiring connection portions 36 are arranged on the rear end surfaces 37A, 37B, and 37C of the step cylindrical portion at intervals.

  In the third embodiment, similarly to the manufacturing method in the first embodiment, a resist 41 is applied or laminated on the piezoelectric body 40, and a pattern is formed by photolithography to form an embedded portion 41A. A metal layer 42 is formed on the bottom and side walls, and a backing material 43A is filled in the embedded portion 41A to form the backing layer 43 (FIGS. 10A to 10F). The piezoelectric body 40 is polished to a predetermined thickness as necessary.

  A frustoconical portion 35 and a stepped cylindrical portion are formed on the back surface side of the embedded portion 41A by multilayer resist film formation, patterning by photolithography, metal layer formation, and patterning by photolithography. A multilayer wiring structure is formed. At that time, if necessary, the resist height position and film thickness distribution are decomposed into a two-dimensional matrix, and the focus height and the resist thickness are adjusted to match the exposure height for each matrix without using a photomask. It is possible to use a method of performing exposure using the exposure dose amount (see Patent Document 3). This exposure method is called non-planar photolithography.

Hereinafter, specific examples of the ultrasonic probe and the manufacturing method thereof according to the present invention will be described by taking, for example, a 24-element front-view ultrasonic probe having an outer diameter of 2.5 mm and an inner diameter of 0.5 mm as an example.
First, a photoresist 41 (Kayaku Microchem Co., Ltd., SU-8) is applied to a piezoelectric film 40 (JFE Mineral Co., Ltd., PMN-PT) having a thickness of 300 μm so as to form a pressure film, and photolithography is performed. An embedded portion 41A is formed through pattern formation (FIGS. 10A and 10B).
Au and Cr are sputtered on the bottom and side walls of the embedded portion 41A, and further, the metal layer 42 is formed by electrolytic plating (FIGS. 10C and 10D).
Next, an epoxy (manufacturer name: Epoxy Technology, EPO-TEK 301) mixed with 8% by volume of tungsten powder is filled into the embedded portion 41A as a backing layer 43 (FIGS. 10E and 10F).
A holding portion 13 having a multilayer wiring structure is formed on the back side of the backing layer 43 using a thick film photoresist (FIGS. 10G, 11A to 11G, and 12A).
Next, the front side of the PMN-PT substrate as the piezoelectric body 40 is polished until the thickness becomes 90 μm (FIG. 12B).
Thereafter, with respect to the PMN-PT substrate as the piezoelectric body 40A, a through hole 51 having an inner diameter of 0.5 mm, and a circumferential groove portion 50 having a radius of 1.0 mm so as to divide the space between the injection and formation of the backing material, The radial groove 50 from the through hole 51 toward the circumferential groove 50 having a radius of 1.0 mm, and the radial radially outward groove from the groove 50 on the circumference having a radius of 1.0 mm. 50 (FIG. 12D).

  FIG. 20 is a diagram showing an SEM image observed from the front side of the piezoelectric body 40 </ b> A in which the groove 50 is formed, in connection with an actual prototype. From this figure, it can be seen that the PMN-PT substrate as the piezoelectric body 40A is a ring array.

Next, the front-side electrode 11C is formed on the surface of the PMN-PT substrate as the piezoelectric body 40A, and the matching layer 14 is formed thereon, whereby the ultrasonic transducer 11 divided into 24 parts is formed.
Next, the wiring part 23 is formed on the outer surface of the glass tube as the insulating tube 21 having a diameter of 3 mm by using non-planar photolithography. Cu (copper) can be used as a wiring material in the wiring part 23.

Next, the wiring part 23 on the glass tube as the insulating tube 21 and the holding part 13 of the transmission / reception part 10 are electrically and mechanically connected using solder or conductive resin (FIG. 15).
Finally, an IC chip 24 for surface mounting made of a high-speed operational amplifier and a chip resistor are connected to the wiring portion 23 on the insulating tube 21. At that time, the three IC chips 24 mounted on the insulating tube 21 are arranged so as to be symmetric with respect to the central axis of the insulating tube 21 (FIG. 7).

  FIG. 21 is a diagram showing an SEM image of the insulating tube 21 in which the wiring part 23 is formed in an example of actual trial manufacture. From this figure, it can be seen that the wiring portion 23 is well formed on the surface of the insulating tube 21.

  FIG. 22 is a diagram showing an SEM image in which an IC chip is mounted on the wiring portion 23 in an example of actual trial manufacture. From this figure, it can be seen that a high-speed operational amplifier and a chip resistor as the IC chip 24 are connected to the wiring portion 23.

The transmission / reception performance of the actually produced ultrasonic probe 1 will be described.
The produced ultrasonic probe 1 was placed in water, and an iron plate was disposed as a reflector on the front side of the ultrasonic probe 1. The ultrasonic probe 1 was driven using a pulse generator (Panametrics model-5900PR), and the reception echo by the ultrasonic probe was monitored.

  FIG. 23A is a diagram showing a result of a one-dimensional simulation of the actually manufactured ultrasonic probe 1, and FIG. 23B is a diagram showing a measurement result of the actually manufactured ultrasonic probe 1. FIG. 22A and 22B, the left vertical axis represents the received voltage (relative value), and the right vertical axis represents the frequency spectrum intensity (relative value, expressed in dB). The horizontal axis is the time axis (μ seconds) and the frequency spectrum (MHz). Although the one-dimensional simulation and the measured value differ in the number of vibrations of the received echo, the center frequency of the frequency spectrum is 20 MHz, and it can be seen that the measurement result is in good agreement with the simulation.

It is the schematic which shows the endoscope with which the ultrasonic probe which concerns on 1st Embodiment was attached. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which follows the CC line of FIG. It is the figure which looked at the transceiver part in an ultrasonic probe from back. It is a figure which shows a connection member typically. It is sectional drawing which follows the DD line | wire of FIG. It is sectional drawing which follows the EE line | wire of FIG. It is an expanded view which shows an example of the wiring pattern formed in a connection member. It is a figure which shows the first half of the production process of the transmission / reception part in an ultrasonic probe. It is a figure which shows the middle stage of the production process of the transmission / reception part in an ultrasonic probe. It is a figure which shows the latter half of the production process of the transmission / reception part in an ultrasonic probe. It is a figure which shows the preparation process of a connection member. FIG. 6 is a schematic view showing another connection member 20. It is a figure which shows the preparation process of the connection member different from FIG. It is a figure which shows the connection process of a transmission / reception part and a connection member. It is a figure which shows the connection method of the transmission / reception part and connection member in the ultrasonic probe which concerns on 2nd Embodiment. It is a typical perspective view which shows the holding | maintenance part in 3rd Embodiment. It is a typical perspective view which shows the modification of the holding | maintenance part in 3rd Embodiment. It is a figure which shows the SEM image observed from the front side of the piezoelectric material in which the groove part was formed in the example actually manufactured. It is a figure which shows the SEM image of the glass tube in which the wiring part was formed in the example actually prototyped. It is a figure which shows the SEM image which concerns on the example actually produced as a trial and mounts the IC chip in the wiring part. (A) is a figure which shows the result of the one-dimensional simulation of the actually manufactured ultrasonic probe 1, and (b) is a figure which shows the measurement result of the actually manufactured ultrasonic probe 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,5: Ultrasonic probe 1A, 33A, 51: Through-hole 2: Catheter 2A: Tip part 3: Endoscope 10: Transmission / reception part 11: Ultrasonic transducer 11A: Separation part 11B, 40, 40 ': Piezoelectric body 11C, 53: Front side electrode 11D: Back side electrode 12: Vibration absorber 13, 33: Holding part 13A: Multilayer wiring structure 13B, 41A: Buried part 13C, 13D: Metal layer 13E: Interlayer insulating film 13F: Buried electrode Part 14: Matching layer 16, 36: Wiring connecting part 16A: First wiring connecting part 16B: Second wiring connecting part 20, 20 ', 20B, 80: Connecting member 20A: Flexible substrate 21: Insulating tube 21A: Shaft Portions 22 and 46: Insulating layer 23: Wiring portion (electrode layer)
23A: 1st connection electrode part 23B: 2nd connection electrode part 23C: Wiring connection part 23D: Connection part 24, 81F, 82C, 83C: IC chip 30: Tube member 33B: Cylindrical part 35: Frustum shape Part 35A: Side part 35B: Rear end part 37A: Rear end face 41, 62, 62A: Resist (photoresist)
42, 42B, 44, 44A, 47, 61B: Metal layer (electrode layer)
42A, 61A: Underlayer 43: Backing layer 43A: Backing material 45, 48, 49: Etching mask 47A: Electrode 50: Groove part 52: Separation part 60: Insulating tube 61C: Wiring part 70: Transmission / reception part 71, 71A, 71B, 71C: Wiring connection portion 81, 82, 83: Tube 81A, 82A, 83A: Connection electrode portion 81D, 82D, 83D: Rear end electrode portion 81E, 82E, 83E: Cable 82B, 83B: IC connection electrode portion

Claims (15)

An ultrasonic transducer disposed in a ring array, a vibration absorber disposed on the rear side of the ultrasonic transducer for each ultrasonic transducer, and a holding unit that holds each of the vibration absorbers. Prepared,
A wiring connection part for each ultrasonic transducer is provided at the rear end of the holding part,
An ultrasonic probe in which a back electrode for each ultrasonic transducer and the wiring connection part are electrically connected by a wiring structure in the holding part.   The ultrasonic probe according to claim 1, wherein a connection member is disposed on the rear side of the holding portion.   The ultrasonic probe according to claim 2, wherein the connection member is configured by one tube or a plurality of concentric tubes.   The ultrasonic probe according to claim 2, wherein the connection member is formed by deforming a flexible substrate or a flexible sheet into a tube shape.   The connection member is provided with a wiring pattern including a connection electrode portion connected to the wiring connection portion, and circuit components for processing signals related to transmission and reception of ultrasonic waves by the ultrasonic transducer are mounted. The ultrasonic probe according to claim 2.   The ultrasonic probe according to claim 1, wherein the wiring connection portion is circumferentially arranged with an interval around an outer peripheral edge portion of a rear end portion of the holding portion.   The ultrasonic probe according to claim 1, wherein the wiring connection portion is disposed at a rear end portion of the holding portion along the same or similar arrangement pattern as the arrangement pattern of the ultrasonic transducers. The holding portion has a through hole and has a truncated cone shape with the through hole as an axis,
The ultrasonic probe according to claim 1, wherein the wiring connection portion is disposed on the rear end surface or the side surface of the holding portion with a space therebetween. The holding portion has a through hole and has a step shape in which the width in the axial direction changes according to the radial direction with the through hole as an axis,
The ultrasonic probe according to claim 1, wherein the wiring connection portion is disposed with a gap on a rear end surface of the holding portion.   An endoscope configured by mounting the ultrasonic probe according to any one of claims 1 to 9 on a distal end portion of a catheter or an endoscope tool. One or a plurality of circumferentially spaced intervals are formed on the back surface of the piezoelectric body, embedded portions are formed in a predetermined pattern, a metal layer is formed for each embedded portion, and a vibration absorber and each of the embedded portions Injecting a backing layer to form a wiring structure on the backing layer, thereby forming a holding portion in which the wiring structure and the backing layer are embedded;
Dividing the piezoelectric body into a single or multiple ring array, and forming a through hole in the piezoelectric body and the holding portion;
A method for producing an ultrasonic probe, comprising: Furthermore, forming a connection pattern by forming a wiring pattern on a cylindrical member or forming a wiring pattern on a flexible sheet or flexible substrate and deforming it into a tube shape;
Connecting each back side electrode in the wiring structure of the holding portion and each connection electrode portion of the wiring pattern;
The manufacturing method of the ultrasonic probe of Claim 11 containing this.   The method for producing an ultrasonic probe according to claim 11, wherein when forming the holding portion, a connection wiring portion corresponding to each backing layer is formed at an interval on an outer peripheral edge of a rear end portion of the holding portion.   The method of manufacturing an ultrasonic probe according to claim 11, wherein when forming the holding portion, a connection wiring portion is formed along the arrangement pattern of the backing layer at a rear end portion of the holding portion.   The method of manufacturing an ultrasonic probe according to claim 11, wherein non-planar photolithography is used when forming the wiring structure.