Abstract:
An ultrasound endoscope includes: an acoustic lens for transmitting/receiving ultrasound; a transducer element generating ultrasound vibration transmitted/received via the acoustic lens; backing material with an insulation property provided on a face of the transducer element opposite to the acoustic lens; a housing accommodating the acoustic lens, the transducer element and the backing material so as to expose a surface of the acoustic lens to an outside; an insulative cooling portion with thermal conductivity higher than thermal conductivity of the backing material, and laminated on a surface of the backing material opposite to a surface in contact with the transducer element; and a signal wire configured with a metal wire extended from the transducer element into the housing through the backing material, the signal wire, including a curved portion curved so that an area of contact with the cooling portion is increased, being covered with the cooling portion.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation application of PCT/JP2015/056504 filed on Mar. 5, 2015 and claims benefit of Japanese Application No. 2014-178310 filed in Japan on Sep. 2, 2014, the entire contents of which are incorporated herein by this reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an ultrasound endoscope having an ultrasound transmitting/receiving portion. 
         [0004]    2. Description of the Related Art 
         [0005]    In an ultrasound endoscope, because of demands for diameter reduction of an insertion portion, sensitivity improvement, and two-dimensionalization of an ultrasound transducer and the like, miniaturization and higher output of the transducer itself are demanded. Accompanying the demands, there is a tendency of increase in heat generation of the transducer itself, and there may be a case where transducer output is restricted because of increase in scope surface temperature caused by the heat generation of the transducer. 
         [0006]    To cope with this, U.S. Patent Application Publication No. 5,545,942 discloses a technique for taking countermeasures against heat by filling heat-absorbing material in a housing of an ultrasound probe. 
       SUMMARY OF THE INVENTION 
       [0007]    An ultrasound endoscope according to an aspect of the invention includes: an acoustic lens for transmitting/receiving ultrasound; a transducer element configured to generate ultrasound vibration transmitted/received via the acoustic lens; backing material having an insulation property that is provided on a face of the transducer element opposite to the acoustic lens; a housing configured to accommodate the acoustic lens, the transducer element and the backing material in a manner that a surface of the acoustic lens is exposed to an outside; an insulative cooling portion with thermal conductivity higher than thermal conductivity of the backing material, the insulative cooling portion being laminated on a surface of the backing material opposite to a surface in contact with the transducer element; and a signal wire configured with a metal wire extended from the transducer element into the housing through the backing material, the signal wire including a curved portion curved so that an area of contact with the cooling portion is increased, and being covered with the cooling portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  relates to a first embodiment of the present invention and is a whole configuration diagram of an ultrasound endoscope; 
           [0009]      FIG. 2  relates to the first embodiment of the present invention and is an explanatory diagram showing a distal end portion of the endoscope; 
           [0010]      FIG. 3  relates to the first embodiment of the present invention and is a cross-sectional view of an ultrasound transmitting/receiving portion; 
           [0011]      FIG. 4  relates to the first embodiment of the present invention and is a cross-sectional view along an A-A line in  FIG. 3 ; 
           [0012]      FIG. 5  relates to the first embodiment of the present invention and is an explanatory diagram showing a curved portion of a signal wire; 
           [0013]      FIG. 6  relates to the first embodiment of the present invention and is an explanatory diagram showing an example in which a heat radiating member is attached; 
           [0014]      FIG. 7  relates to a second embodiment of the present invention and is a cross-sectional view of an ultrasound transmitting/receiving portion; 
           [0015]      FIG. 8  relates to the second embodiment of the present invention and is a cross-sectional view along a B-B line in  FIG. 7 ; and 
           [0016]      FIG. 9  relates to the second embodiment of the present invention and is an explanatory diagram showing an example in which a heat radiating member is attached. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Embodiments of the present invention will be described below with reference to drawings. 
         [0018]    First, a first embodiment of the present invention will be described. As shown in  FIG. 1 , an ultrasound endoscope  1  of the present embodiment is an electronic scanning type ultrasound endoscope having an ultrasound transducer unit  30  on a distal end side of an insertion portion  2  which is formed in an elongated tube shape and is inserted into a body cavity or the like. On a proximal end side of the insertion portion  2  of the ultrasound endoscope  1 , an operation portion  3  which is also used as a grasping portion is connectedly arranged. On a distal end side of a universal code  4  extended from a side portion of the operation portion  3 , a connector portion  5  is arranged. 
         [0019]    The insertion portion  2  is configured having a rigid portion  6  connectedly arranged in the ultrasound transducer unit  30  on the distal end side, a bending portion  7  connectedly arranged in a rear end side of the rigid portion  6  and configured to freely bend, for example, in an up-and-down direction, and a flexible tube portion  8  connectedly arranged in a rear end side of the bending portion  7 . The flexible tube portion  8  is a long tubular member with a small diameter which is provided between the bending portion  7  and the operation portion  3  and formed to have flexibility so as to be passively flexible. 
         [0020]    The operation portion  3  has a bend preventing portion  3   a  which is connected to the flexible tube portion  8 , covering a proximal end of the flexible tube portion  8 , and a grasping portion  3   b  which is connectedly arranged in the bend preventing portion  3   a  and which is grasped by a hand of a user when the user uses the ultrasound endoscope  1 . On an upper end side of the grasping portion  3   b , various kinds of operation members are arranged. On a part positioned on a lower end side of the grasping portion  3   b , which is an upper part of the bend preventing portion  3   a , a treatment instrument insertion port  9  for guiding a treatment instrument into the body cavity, and the like are provided. As the operation members provided on the operation portion  3 , for example, a bending lever  10  for performing a bending operation of the bending portion  7 , and a plurality of operation buttons  11  for performing an air/water feeding operation or a suction operation, each of operations corresponding to image pickup, illumination and the like are included. 
         [0021]    The universal code  4  passes from a distal end of the insertion portion  2  to the operation portion  3  through insides of the bending portion  7  and the flexible tube portion  8 . Furthermore, the universal code  4  is a composite cable in which various kinds of signal wires and the like extending from the operation portion  3  as well as a light guide of a light source apparatus (not shown) are inserted, and, furthermore, an air/water feeding tube extended from an air/water feeding apparatus (not shown) is inserted. The connector portion  5  arranged on the distal end side of the universal code  4  is configured having an ultrasound connector  5   a  for connecting to an ultrasound observation apparatus (not shown), an electrical connector portion  5   b  to which various kinds of signal cables are connected, and a light source side connector  5   c  for connecting to the light source apparatus and the air/water feeding apparatus (not shown). 
         [0022]    Next, a configuration of the distal end side of the insertion portion  2  will be described with use of  FIG. 2 . As shown in  FIG. 2 , the rigid portion  6  on the distal end side of the insertion portion  2  is provided with an objective lens window  20  constituting an observation optical system, an illumination lens window  21  constituting an illumination optical system, a treatment instrument guiding port  22  from which a treatment instrument such as a puncture needle is guided out, and the like. 
         [0023]    On the other hand, the ultrasound transducer unit  30  connectedly arranged in the rigid portion  6  is configured having an ultrasound transmitting/receiving portion  15  and a nosepiece  16  which is a housing for accommodating the ultrasound transmitting/receiving portion  15 . The ultrasound transmitting/receiving portion  15  is integrally arranged and held in a housing portion formed in a substantially central part of the nosepiece  16  and Ruining a recess portion. The ultrasound transmitting/receiving portion  15  is provided mainly with an acoustic lens portion  15   a  which forms an ultrasound transmitting/receiving surface in a longitudinal axis direction of the insertion portion  2  and a plurality of transducer elements  15   b  arranged along a convex surface inside the acoustic lens portion  15   a.    
         [0024]    Further, a substantially cylindrical protruding portion  16   a  is provided at a distal end of the nosepiece  16 . A first balloon holding groove  17   a  is foamed on a proximal-end-side outer circumference of the protruding portion  16   a , and a second balloon holding groove  17   b  is formed on an outer circumference of a coupling portion of the nosepiece  16  to be coupled with the rigid portion  6 . For example, a thin balloon having a high contractility which is formed, for example, with silicon rubber or latex rubber is detachably interposed between the first balloon holding groove  17   a  and the second balloon holding groove  17   b , covering the nosepiece  16 . 
         [0025]    Next, a signal wiring system of the ultrasound transducer unit  30  will be described. 
         [0026]    As shown in  FIG. 3 , the plurality of transducer elements  15   b  of the ultrasound transmitting/receiving portion  15  are electrically connected to a wiring substrate  25  on which corresponding signal lines are arranged as a pattern, via a plurality of signal wires  26 , and the wiring substrate  25  is accommodated in the nosepiece  16 . A plurality of signal cables  27  forming driving lines, the signal line and grounding lines are extended from the wiring substrate  25 . The signal cables  27  are inserted through the insertion portion  2  and connected to the ultrasound connector  5   a.    
         [0027]    More specifically, in the ultrasound transducer unit  30 , upper electrode sides of the transducer elements  15   b  are bonded to a back side of the acoustic lens portion  15   a  held in the substantially central portion of the nosepiece  16  via acoustic matching layers  31  and  32  for performing adjustment to obtain predetermined acoustic impedance. As the transducer element  15   b , for example, a piezoelectric type element obtained by sandwiching a well-known piezoelectric element between an upper electrode and a lower electrode, or a capacitance type element obtained by separating the upper electrode and the lower electrode by a column in order to make a space with a predetermined distance between the upper electrode and the lower electrode is applicable. 
         [0028]    On a back side of the lower electrodes of the transducer elements  15   b , backing material  33  for attenuating unnecessary ultrasound is arranged. As the backing material  33 , for example, what is obtained by combining ceramic particles such as alumina, zirconia and titanium oxide as filler material, with material having an insulation property, such as epoxy resin, silicone, urethane or various kinds of elastomers, as basic material can be used. 
         [0029]    Furthermore, on a back side of the backing material  33 , a cooling portion  34  for radiating heat of and cooling the transducer elements  15   b  is laminated. The plurality of signal wires  26  connecting the respective transducer elements  15   b  and the wiring substrate  25  are inserted through the backing material  33  up to the cooling portion  34 , and electrically connected to the wiring substrate  25 . 
         [0030]    Metal wires the surface of which is plated with solder, tin, nickel, copper, gold or the like are used as the signal wires  26 . As shown in  FIGS. 3 and 4 , after being curved and bent at positions inside the cooling portion  34  separated from a back side of the transducer elements  15   b  by a predetermined distance, the signal wires  26  are individually connected to a plurality of lands  25   a  of the wiring substrate  25 . That is, by curving wirings of the signal wires  26  in the cooling portion  34  and forming curved portions  35 , such a configuration is made that an area of contact between outer surfaces of the signal wires  26  and a member forming the cooling portion  34  is increased. 
         [0031]    Note that, though it is assumed in  FIGS. 3 and 4  that the plurality of transducer elements  15   b  are connected to the wiring substrate  25  via a common upper electrode, and the curved portion  35  is provided for each signal wire  26  connected to the lower electrode of each transducer element  15   b  and connected to the wiring substrate  25 , the curved portion  35  may be provided for signal wires of both of the upper and lower electrodes. 
         [0032]    Here, the cooling portion  34  has an insulating property and is formed with material having higher thermal conductivity than that of the backing material  33 . For example, by forming the cooling portion  34  with material obtained by mixing more ceramic particles than the backing material  33  with same basic resin material as the backing material  33 , radiation performance (cooling performance) is improved. 
         [0033]    In such a wiring system of the signal wires  26  which include the curved portions  35  covered with the cooling portion  34 , when each transducer element  15   b  is driven for transmission/reception of ultrasound, and heat is generated in each transducer element  15   b , the heat is transferred to each signal wire  26 . The heat transferred to the signal wire  26  is transferred to the curved portion  35  in the cooling portion  34  laminated on the back side of the backing material  33 . Since the curved portion  35  has a large area of contact with a member of the cooling portion  34  having high thermal conductivity is large, the heat generated in the transducer element  15   b  is effectively radiated, and it is possible to efficiently emit the heat generated in the transducer element  15   b  to an outside. 
         [0034]    In this case, it is possible to form a part of the signal wire  26  to be arranged in the cooling portion  34 , in a thin flat plate shape and curve the part in the flat plate shape to make a curved portion  35 A as shown in  FIG. 5 . By using the curved portion  35 A in the flat plate shape, it is possible to further increase the area of contact with a member constituting the cooling portion  34  and improve radiation performance more. 
         [0035]    Further, a heat sink  36  made of metal material or the like and stuck to an outer surface of the cooling portion  34  may be arranged outside the cooling portion  34  as shown in  FIG. 6 . The heat sink  36  is arranged between the outer surface of the cooling portion  34  and an inner wall surface of the nosepiece  16 , and one end is extended up to the rigid portion  6  on the distal end side of the insertion portion  2 , so that the heat transferred from the curved portions  35  of the signal wires  26  to the member constituting the cooling portion  34  is emitted to an endoscope body side where the nosepiece  16  is connectedly arranged. 
         [0036]    As described above, in the present embodiment, the signal wires  26  connected to the transducer elements  15   b  are extended into the cooling portion  34  formed with a member having high thermal conductivity on the back side of the backing material  33 , and the curved portions  35  obtained by curving and bending the signal wires  26  are arranged in the cooling portion  34 . Thereby, it is possible to efficiently radiate heat generated in the transducer elements  15   b  from the curved portions  35  with a large area of contact with the member constituting the cooling portion  34 , without requiring a large space for heat radiation. 
         [0037]    Especially in an ultrasound endoscope from which miniaturization of a distal end portion and higher output of a transducer are required, since it is possible to efficiently radiate heat of the transducer elements  15   b  without requiring a cooling portion with a large capacity, it is possible to suppress increase in surface temperature of the acoustic lens portion  15   a  and efficiently perform ultrasound observation without unnecessarily restricting output of the transducer. 
         [0038]    Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the cooling portion  34  in which the curved portions  35  of the signal wires  26  are arranged is changed to improve radiation performance more. 
         [0039]    More specifically, as shown in  FIG. 7 , a cooling portion  34 A of the second embodiment is configured, with a bar-shaped heat transfer member  40  formed with material having high thermal conductivity buried inside. An outer surface of the heat transfer member  40  with which the signal wires  26  come into contact is at least electrically insulated, and is formed with ceramic or metal material or the like with a high heat capacity. As shown in  FIG. 8 , the curved portions  35  of the signal wires  26  are wound and stuck around the heat transfer member  40 . 
         [0040]    Note that, in this case, for the curved portion  35 , it is also possible to form a part of the signal wire  26  in a thin flat plate shape as described with regard to  FIG. 5  of the first embodiment, and wind and stick the flat-plate-shaped part around the heat transfer member  40 . Thereby, it is possible to increase the area of contact between the curved portion  35  and the heat transfer member  40  more and improve radiation performance more. 
         [0041]    In such a configuration, heat generated in the transducer elements  15   b  is transferred through the signal wires  26 , and, in the cooling portion  34 A, the heat is transferred from the curved portions  35  of the signal wires  26  to the heat transfer member  40  and emitted to the outside. Since the curved portions  35  are arranged and stuck to the heat transfer member  40  having higher thermal conductivity in the cooling portion  34 A, the heat from the curved portions  35  can be quickly emitted to the outside. 
         [0042]    In this case also, a heat sink  41  made of metal material or the like may be arranged at an end portion of the heat transfer member  40  exposed from the cooling portion  34 A, as shown in  FIG. 9 . The heat sink  41  is arranged along the inner wall surface of the nosepiece  16  and extended up to the rigid portion  6  on the distal end side of the insertion portion  2 , similarly to the heat sink  36  described in the first embodiment, and makes it possible to quickly emit heat transferred from the curved portions  35  of the signal wires  26  to the heat transfer member  40  of the cooling portion  34 A, to the endoscope body side where the nosepiece  16  is connectedly arranged. 
         [0043]    The second embodiment makes it possible to efficiently radiate heat generated in the transducer elements  15   b  from the curved portions  35  of the signal wires  26  without requiring a large space for heat radiation, similarly to the first embodiment. In the second embodiment, since the curved portions  35  are arranged and stuck to the heat transfer member  40  having high thermal conductivity in the cooling portion  34 A, radiation performance can be further improved.