Abstract:
A manufacturing method for an ultrasonic probe including the steps of forming a plurality of unit fixing plates. Laminating each unit fixing plates to one another to form a fixing base and inserting lead wires into grooves formed in the fixing base. Partially cutting away and smoothing both principal surfaces of the fixing base to expose lead wires. Fixing a piezoelectric plate to one principal surface of the fixing base and cutting out between the lead wires in a one dimension direction and a two dimension direction, to divide up said piezoelectric plate and the fixing base into a plurality of piezoelectric elements.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of, and claims priority to, U.S. patent application Ser. No. 11/111,170, filed Apr. 21, 2005, which claims priority to Japanese Patent Application No. JP 2004-132495, filed Apr. 28, 2004. The content of each of the above-noted applications is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to an ultrasonic probe in which piezoelectric elements are arrayed in a two dimensional form, and in particular to an ultrasonic probe in which lead wires are led out with a high degree of accuracy, and to a manufacturing method therefor. 
     Ultrasonic probes are widely used, for example, as the ultrasonic transmitting and receiving section in medical diagnostic equipment. As such equipment, there are those which have piezoelectric elements arrayed in a two-dimensional form and which scan electronically in a two-dimensional direction for high resolution. 
       FIG. 6  is a perspective view for explaining a conventional ultrasonic probe. 
     This ultrasonic probe comprises a plurality of piezoelectric elements  1   a ,  1   b  and  1   c  arrayed on the upper surface of a fixing base  2  in a two-dimensional direction (lengthwise direction (X) and widthwise direction (Y)). Each of the piezoelectric elements  1   a ,  1   b  and  1   c  has driving electrodes  3   a  and  3   b  on both of their principal surfaces (upper surface and lower surface). The fixing base  2  normally comprises a damper material such as rubber that has a vibration damping function for inhibiting vibration, to prevent reflection of ultrasonic waves. Generally, the damper material is called a backing material. Moreover, a lead wire  4  is connected to the driving electrode  3   b  provided on the lower surface of the piezoelectric element  1 , and passes through the fixing base  2  and is led out to the back side thereof. Here, the lead wire  4  is exposed on the back side of the fixing base  2 , and is connected to a power supply cable by a connector (not shown). 
     In order to manufacture such a conventional ultrasonic probe, first of all, for example as shown in  FIG. 7 , a plurality of comb shaped integrated lead wires  4 A in which the lead wires  4  are formed from a thin plate and are connected by a connection portion  5 , are arrayed in parallel, inside a mold box (not shown). Then, a damper material of synthetic resin that constitutes the fixing base  2 , is poured into the mold box, and allowed to harden to integrate the integrated lead wires  4 A. Next, both principal surfaces (upper surface and lower surface) of the damper material are ground to expose the connection portion  5  and a rear end portion of the integrated lead wire  4 A [Refer to Japanese Unexamined Patent Publication (TOKKYO KOKAI) No. Hei 10-282074 (Japanese Patent No. 3507655)]. 
     Finally, a piezoelectric plate  6  is fixed to the one principal surface of the fixing base  2  which had the connection portion  5  exposed, and the areas between the respective lead wires  4  and between the integrated lead wires  4 A are cut away to divide up the fixing base  2  into individual piezoelectric elements  1   a ,  1   b  and  1   c  (see  FIG. 6 ). As a result, the electrically connected lead wires  4  are led out from the lower surface of the individual piezoelectric elements  1 . 
     However, in the conventional ultrasonic probe of the above construction, since a damper material is used as the fixing base  2 , then for example when connecting the lead wires  4  exposed on the underside, to the connector (not shown) using solder, the connection operation becomes difficult due to a lack of heat resistance. Moreover, accurately aligning the comb shaped integrated lead wire  4 A inside the mold box is difficult. Therefore, there is a problem in that array accuracy of the lead wires  4  is reduced, and so forth. 
     An object of the present invention is to provide an ultrasonic probe in which the array accuracy of the lead wires, and the heat resistance when connecting to a connector are enhanced, and a manufacturing method therefor. 
     SUMMARY OF THE INVENTION 
     The ultrasonic probe of the present invention is one where, in an ultrasonic probe in which a plurality of piezoelectric elements are arrayed in a two-dimensional direction on a fixing base, and lead wires from the lower surface of each of the piezoelectric elements that are electrically connected and are inserted through the fixing base are led out, the construction is such that, the fixing base has an opening portion in an array direction of the piezoelectric elements, and comprises unit fixing plates laminated in the array direction, and grooves through which the lead wires are inserted, are formed on one principal surface of the unit fixing plates, and damper material is filled into the opening portion. 
     Furthermore, the manufacturing method for an ultrasonic probe of the present invention, comprises, in a manufacturing method for an ultrasonic probe in which a plurality of piezoelectric elements are arrayed in a two dimensional direction on a fixing base, and lead wires from a lower surface of each of the piezoelectric elements that are electrically connected and are inserted into the fixing base are led out: a step for laminating a plurality of unit fixing plates that have an opening portion passing through a plate surface and have grooves provided in parallel in a vertical direction of the plate surface, to form a fixing base; a step for inserting lead wires into each groove in the unit fixing plates of the laminated fixing base; a step for cutting away both principal surfaces of the fixing base to expose the lead wires; a step for fixing a piezoelectric plate to an upper surface of the fixing base; and a step for cutting out between the lead wires of the fixing base to divide up the fixing base into a plurality of piezoelectric elements. 
     According to the ultrasonic probe of the present invention, due to the thickness of the unit fixing plate, and grooves formed therein, the array accuracy of the lead wires is enhanced. Furthermore, since damper material is filled into the opening portion formed in the fixing base, then by selecting the material for the fixing base, heat resistance when connecting to a connector can be improved. Moreover, according to the manufacturing method for an ultrasonic probe of the present invention, the ultrasonic probe of the present invention can be manufactured easily. 
     BEST MODE FOR CARRYING OUT THE INVENTION 
     A best mode for the ultrasonic probe of the present invention, is to make the fixing base from ceramic, and as a result, heat resistance when connecting to the connector is improved. Moreover, opening portions are provided beforehand in the unit fixing plates. Therefore, the opening portions can be formed easily when laminating the unit fixing plates to construct the fixing base. 
     Also, a best mode for the manufacturing method of the ultrasonic probe of the present invention is to mirror-polish both principal surfaces of the unit fixing plates, and laminate them by direct union. As a result, an adhesive becomes unnecessary, and the thickness of the adhesive layer can be disregarded. Therefore the degree of orientation of the lead wires can be improved. 
     Furthermore, in the manufacturing method for the ultrasonic probe of the present invention, the unit fixing plates are fusion laminated by glass which is filled into other grooves provided between the aforementioned grooves. 
     Moreover, in the manufacturing method for the ultrasonic probe of the present invention, the lead wires inserted into the grooves are made to be a comb shaped integrated lead wire. As a result, insertion of the lead wires into the grooves become easier. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an upper surface perspective view for explaining a first embodiment of an ultrasonic probe of the present invention. 
         FIG. 2  is a back face perspective view of the ultrasonic probe shown in  FIG. 1 . 
         FIG. 3  is a perspective view of a unit fixing plate used in the first embodiment of the ultrasonic probe of the present invention. 
         FIG. 4  is an assembly perspective view illustrating a method of insertion of integrated lead wires into a fixing base used in the first embodiment of the ultrasonic probe of the present invention. 
         FIG. 5  is a plan view of a fixing plate used in a second embodiment of the ultrasonic probe of the present invention. 
         FIG. 6  is a perspective view of a conventional ultrasonic probe. 
         FIG. 7  is an assembly diagram showing a manufacturing method for a conventional ultrasonic probe. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
       FIG. 1  to  FIG. 3  are diagrams for explaining a first embodiment of an ultrasonic probe of the present invention.  FIG. 1  is an upper surface perspective view of the ultrasonic probe,  FIG. 2  is a back face perspective view of the ultrasonic probe shown in  FIG. 1 , and  FIG. 3  is perspective view of a unit fixing plate of the ultrasonic probe. 
     As shown in  FIG. 1 , in the ultrasonic probe of the present invention a plurality of piezoelectric elements  1   a ,  1   b  and  1   c , which have driving electrodes  3   a  and  3   b  on their upper and lower surfaces, are arrayed on a fixing base  2  in a two dimensional direction (lengthwise (X) and widthwise (Y) direction). Lead wires  4  shown in  FIG. 2  are respectively connected to the driving electrodes  3   b  provided on the lower surfaces of the piezoelectric elements  1   a ,  1   b  and  1   c . As shown in  FIG. 2 , the lead wires  4  are made so as to be exposed from the lower surface of the fixing base  2 . 
     In this first embodiment, the fixing base  2  is formed from ceramic, and has an opening portion  7  spanning in the array direction of the piezoelectric elements  1   a ,  1   b  and  1   c  (for example the lengthwise direction (X)). A damper material having a vibration damping function, is filled into this opening portion  7 . Moreover, the fixing base  2  comprises a plurality of unit fixing plates  8  laminated in the array (X) direction. 
     As shown in  FIG. 3 , the respective unit fixing plates  8  have opening portions passing through their plate surfaces, and a plurality of grooves  9   a  are provided on one principal surface, extending in a vertical direction orthogonal to the array direction (lengthwise direction (X)). Furthermore, for example, both principal surfaces of the unit fixing plate  8  are mirror-polished, and each of the unit fixing plates  8  are laminated by intermolecular bonding by direct union, thus constructing the fixing base  2 . 
     In the ultrasonic probe of the present invention constructed in this way, first a plurality of ceramic flat plates having the opening portions  7  as shown in  FIG. 3  are cast by firing, and then the unit fixing plates  8  are formed by forming a plurality of grooves  9   a  in parallel in the vertical direction. Then, both principal surfaces of the unit fixing plates  8  are mirror-polished. Next, the unit fixing plates  8  are superposed and heat treated. As a result, each of the unit fixing plates  8  is laminated by direct intermolecular bonding by van der Waals force bonding. As a result, the fixing base  2  that has the opening portion  7  in the array direction (lengthwise direction (X)), and that has a plurality of first grooves  9   a  in the vertical direction is obtained. 
     Next, as shown in  FIG. 4 , the lead wires  4  are connected by a connection portion  5  and the comb shaped integrated lead wire  4 A is inserted into the grooves  9   a  in the fixing base  2 . Then, both principal surfaces of the fixing base  2  are partially removed to expose the lead wires  4  on both principal surfaces. Next, the damper material is poured into the opening portion  7  of the fixing base  2 , and hardened. Finally, the connection portion  5  is cut away and the one principal surface of the fixing base  2  is smoothened, after which a piezoelectric plate (see the piezoelectric plate  6  shown in  FIG. 1 ) is fixed on the one principal surface of the fixing base  2 . In addition, the piezoelectric plate and the area between the lead wires  4  are cut using a dicing saw or the like, to form cut outs, first in a one-dimensional direction in the fixing base  2 , and then in a two-dimensional direction, to divide up the area. By cutting between each of the lead wires  4 , the fixing base  2  is made to have the respective piezoelectric elements  1   a ,  1   b  and  1   c . Moreover, the lead wires  4  electrically connected to each of the piezoelectric elements are led out from the lower surface of each of the piezoelectric elements  1   a ,  1   b  and  1   c  ( FIG. 1  shows the state in which the piezoelectric plate  6  is divided up into each of the piezoelectric elements  1   a ,  1   b  and  1   c , but does not show the fixing base  2  being divided up). 
     According to such a construction, due to the thickness of the unit fixing plate  8  and the depth of the formed grooves  9   a , the parallel direction (widthwise direction (Y)) array accuracy of the comb shaped lead wire  4 A a can be enhanced. Moreover, due to the grooves  9   a  formed in the unit fixing plate  8 , the array accuracy (comb shaped lead wires  4 A) in the one-dimensional direction (lengthwise direction (X)) can be enhanced. Furthermore, since the unit fixing plate  8  is formed from ceramic, heat resistance can be enhanced. Moreover, since the damper material is filled into the opening portion  7  formed in the fixing base  2 , the vibration damping function can be sufficiently demonstrated. 
     Second Embodiment 
       FIG. 5  is a plan view of a fixing base of an ultrasonic probe for explaining a second embodiment of the ultrasonic probe of the present invention, and the manufacturing method therefor. 
     In this second embodiment, as shown in  FIG. 5 , the fixing base  2  that fixes the piezoelectric elements  1  arrayed in the two-dimensional direction, is laminated by joining together a plurality of unit fixing plates  8  made of ceramic. That is to say, between the grooves  9   a  in each of the unit fixing plates  8 , other grooves  9   b  with shallower groove depths are provided. Then granulated glass (frit glass) is embedded in the grooves  9   b , and is melted to fill the grooves. Next, the unit fixing plates  8  are superposed with their principal surface directions the same, and are fired. As a result, the glass  10  filled inside the grooves  9   b  is re-melted, and the plurality of unit fixing plates  8  are joined together to give a laminated body (fixing base  2 ). 
     Then, as with the first embodiment the comb shaped integrated lead wire  4 A is inserted into the grooves  9   a  as shown in  FIG. 4 , and both principal surfaces of the fixing base  2  are partially cut away to expose the lead wires  4 . Moreover, the piezoelectric plate is fixed on one principal surface of the fixing base  2 , and the areas between the lead wires  4  are cut and divided up in a similar way to that described above, and individual piezoelectric elements arrayed in a two-dimensional direction are obtained. Also in such a construction, similarly to the first embodiment, the array accuracy of the lead wires in a two-dimensional direction (lengthwise and widthwise directions), and the heat resistance when connecting to a connector can be enhanced. 
     In the above embodiments, each of the unit fixing plates  8  is joined together by direct union or glass fusion. However, the unit fixing plates  8  may also be joined to each other using a high melting point adhesive for example. Furthermore, the comb shaped integrated lead wire  4 A is inserted into the grooves  9   a  after the joining together of the unit fixing plates  8  to form the fixing base  2 . However, the unit fixing plates  8  may be joined to each other to form the fixing base  2 , in a state in which the comb shaped integrated lead wires  4 A are inserted into each of the grooves  9   a  of the unit fixing plates  8 . 
     Also, the lead wires are in the form of the comb shaped integrated lead wire  4 A. However these may be individual lead wires. Moreover, the opening portion  7  is formed beforehand in the unit fixing plate  8 . However, the opening portion  7  may be formed in the fixing base  2  which is already formed from the laminated unit fixing plates  8 . Furthermore, the grooves  9   a  are formed after the firing of the unit fixing plates  8 . However at the time of firing a green sheet (ceramic coating), the grooves  9   a  may be already formed.