JP5349141B2 - Ultrasonic probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the enhancement of yield in an ultrasonic probe having a two-dimensional array structure. <P>SOLUTION: The ultrasonic probe includes a plurality of vibrator groups 10 arranged in a two-dimensional state. Each of the respective vibrator groups 10 has a plurality of vibrators 50 arranged in a two-dimensional state. A plurality of first substrates 30 are each electrically connected to a plurality of the vibrator groups 10. A second single substrate 40 is electrically connected to a plurality of the first substrates 30. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an ultrasonic probe used in an ultrasonic diagnostic apparatus, an ultrasonic flaw detection apparatus, or the like.

  There are ultrasonic probes used in ultrasonic diagnostic apparatuses, ultrasonic flaw detection apparatuses, and the like. As an application of the ultrasonic probe, there is a two-dimensional array probe having a two-dimensional array structure. The two-dimensional array probe has a single transducer group having a plurality of transducers arranged two-dimensionally. In order to realize a two-dimensional array structure, it is important to extract signal leads from each of a plurality of vibrators. Patent Document 1, Patent Document 2, and Patent Document 3 disclose a structure in which a signal lead is drawn out by electrically and mechanically connecting a single vibrator group and a printed wiring board. Further, Patent Document 4 proposes a structure in which an IC (integrated circuit) substrate is arranged in a single vibrator group.

  Such a two-dimensional array probe is manufactured as follows, for example. First, as shown in the figure, a single transducer group having a plurality of transducers arranged in a two-dimensional manner is prepared. A signal lead is formed on the back surface of each vibrator. Further, a printed wiring board (or IC board) having signal lead pads having the same arrangement pitch as the signal leads on the surface is prepared. The vibrator group and the flexible wiring board are connected so that the back surface of the vibrator group and the signal lead pad face each other. Thereby, the signal lead connected to the vibrator is connected to the signal lead pad on the printed wiring board. The signal lead connected to the signal lead pad is electrically connected to a wiring pattern formed on the printed wiring board or an electronic circuit integrated and mounted on the IC board.

  As another manufacturing method, there is a method of dividing the transducer into an array after connecting the back surface of the transducer block before being divided into an array and a printed wiring board.

In any method, the area of the connection surface between the transducer group and the flexible wiring board increases as the aperture diameter (number of transducers) of the transducer group increases. At that time, if both opposing surfaces are not flat, an electrical connection failure occurs and the yield deteriorates. In addition, since the area of the printed wiring board (or IC board) must be increased, the yield of the printed wiring board (or IC board) itself is also deteriorated.
JP 2001-27451 A US Pat. No. 5,311,095 US Pat. No. 5,267,221 US Pat. No. 6,551,248

  In an ultrasonic probe having a two-dimensional array structure, an improvement in yield is achieved.

  An ultrasonic probe according to an aspect of the present invention includes a plurality of transducer groups having a plurality of transducers arranged two-dimensionally, and a plurality of first transducers that are electrically connected to the plurality of transducer groups, respectively. A substrate, and a single second substrate electrically connected to the plurality of first substrates.

  According to the present invention, it is possible to improve the yield of an ultrasonic probe having a two-dimensional array structure.

  Hereinafter, an ultrasonic probe according to an embodiment of the present invention will be described with reference to the drawings. The ultrasonic probe according to this embodiment is used in an ultrasonic diagnostic apparatus, an ultrasonic flaw detection apparatus, and the like.

  FIG. 1 is a perspective view showing a schematic configuration of a main part of the ultrasonic probe according to the present embodiment. FIG. 2 is a cross-sectional view of the main part of the ultrasonic probe. As shown in FIGS. 1 and 2, the ultrasonic probe has a two-dimensional array structure. That is, this ultrasonic probe has a plurality of transducer groups 10 arranged in a two-dimensional manner. The acoustic matching material 20 is attached to the upper surface of the plurality of transducer groups 10. A plurality of first substrates 30 are mechanically and electrically connected to the lower surfaces of the plurality of transducer groups 10. A single second substrate 40 is mechanically and electrically connected to the lower surfaces of the plurality of first substrates 30.

  Each transducer group 10 has a plurality of transducers 50 arranged two-dimensionally.

  Specifically, the vibrator 50 includes a piezoelectric body 52 having a prismatic shape, a ground electrode 54 formed on the upper surface of the piezoelectric body 52, and a signal electrode 56 formed on the lower surface of the piezoelectric body 52. The piezoelectric body 52 is formed of a piezoelectric ceramic such as barium titanate, lead zirconate titanate (PZT), or lithium sulfate (LH). The ground electrode 54 is grounded. The ground electrode 54 and the signal electrode 56 are each formed of a metal thin film such as a copper foil. The ground electrode 54 and the signal electrode 56 are formed by, for example, vapor deposition or sputtering. A signal lead (not shown) for electrically pulling out the signal electrode 56 to the outside is attached to the signal electrode 56. The piezoelectric body 52 may have a laminated structure of a single piezoelectric material or a laminated structure of a plurality of piezoelectric materials, in addition to the structure made of a single piezoelectric material as in this embodiment. Furthermore, it is also possible to take a laminated structure of a piezoelectric material and a back acoustic material (backing material). In the case of a laminated structure of a piezoelectric material and a backing material, the laminated structure of the piezoelectric material and the backing material can be completely separated as in this embodiment, while only the piezoelectric material is separated and the backing material is connected. It is also possible to form a layered structure.

  The vibrators 50 are arranged along the vertical direction and the horizontal direction. The vibrator 50 receives a drive signal from an ultrasonic diagnostic apparatus main body (not shown) and generates ultrasonic waves in the thickness direction.

  The first substrate 30 is preferably a printed wiring board or an IC (integrated circuit) board. The printed wiring board is formed by forming a plurality of conductive wiring patterns on a flexible insulating substrate and forming an insulating resin that covers the plurality of wiring patterns. An IC substrate has an electronic circuit mounted on a semiconductor substrate. The first substrate 30 according to the present embodiment can be implemented by either a printed wiring board or an IC board, but is assumed to be a printed wiring board in order to specifically describe the following.

  The first substrate 30 has a first substrate body 31 formed of a flexible insulator. The shape and area of the upper and lower surfaces of the first substrate body 31 are substantially equal to the shape and area of the lower surface of the transducer group 10 to be connected. Further, the upper and lower surfaces of the first substrate body 31 are formed flat. A plurality of signal lead pads 32 for signal input / output are mechanically attached to the upper surface of the first substrate body 31. Bumps 33 are attached to the signal lead pad 32. The bump 33 is a conductor such as a metal having a spherical shape. The arrangement pitch of the signal lead pads 32 and the bumps 33 provided on the upper surface is the same as the arrangement pitch of the signal leads attached to the signal electrode 56. That is, the number of signal lead pads 32 is equal to the number of vibrators 52 to be connected. The bump 33 is electrically connected to a signal lead attached to the signal electrode 56. The first substrate body 31 is provided with a through electrode 34 for electrically connecting the upper surface and the lower surface. The through electrode 34 is made of a metal thin film formed in a through hole that penetrates the first substrate body 31 and reaches the upper surface and the lower surface. The through electrode 34 and the signal lead pad 32 are electrically connected via a wiring pattern (not shown) formed on the upper surface of the first substrate body 31.

  The first substrate body 32 and the vibrator group 10 are mechanically bonded by an adhesive 60 such as a resin, for example.

  A plurality of signal lead pads 35 and bumps 36 are also attached to the lower surface of the first substrate body 31. The number of signal lead pads 35 on the lower surface (number of bumps 36) is smaller than the number of signal lead pads 32 on the upper surface (number of bumps 33). The signal lead pad 35 and the through electrode 34 are electrically connected via a wiring pattern (not shown) formed on the lower surface of the first substrate body 31. With such a configuration of the first substrate 30, the signal lead of the signal electrode 56 can be electrically drawn out to the lower surface side of the first substrate 30.

  The second substrate 40 has a second substrate body 41. Typically, the second substrate body 41 has a quadrangular shape, and at least the upper surface of the second substrate body 41 is formed flat. On the upper surface of the second substrate body 41, signal lead pads 42 having the same arrangement pitch as that of the signal lead pads 35 arranged on the lower surface of the first substrate body 31 are formed. The number of signal lead pads 42 formed on the upper surface of the second substrate body 41 is equal to the total number of bumps 36 formed on the lower surface of the plurality of first substrate bodies 31 (total number of signal lead pads 35). The signal lead pad 42 is in contact with the bump 36 on the lower surface of the first substrate body 31.

  The second substrate body 41 and the first substrate body 31 are mechanically bonded with an adhesive such as resin, for example. As described above, the upper surface of the second substrate 40 is mechanically and electrically connected to the lower surfaces of the plurality of first substrates 30. For this reason, the upper surface of the second substrate body 41 of the second substrate 40 must have an area equal to or larger than the total area of the lower surfaces of the plurality of first substrates 30. As the second substrate 40, a printed wiring board and an IC substrate are conceivable. However, the IC substrate cannot have a large area connectable to the plurality of first substrates 30 in the manufacturing process. Therefore, a printed wiring board that can be designed in a large area is suitable as the second substrate 40.

  Further, the number of signal lead pads 35 on the connection surface between the first substrate 30 and the second substrate 40 is smaller than the number of signal lead pads 32 on the connection surface between the transducer group 10 and the first substrate 30. . In other words, the number of signal leads (number of channels) drawn to the signal lead pad 35 is smaller than the number of signal leads (number of channels) drawn to the signal lead pad.

  The upper surface and the lower surface of the second substrate body 41 are communicated with each other through a through electrode (not shown). With such a configuration of the first substrate 30 and the second substrate 40, the signal lead of the signal electrode 56 can be drawn out to the lower surface of the second substrate 40. The signal lead drawn to the lower surface of the second substrate 40 is covered in a cable shape and connected to the ultrasonic diagnostic apparatus main body.

  The acoustic matching material 20 serves to suppress reflection of ultrasonic waves due to a difference in acoustic impedance between the subject (not shown) and the vibrator 52. The acoustic matching material 20 is formed of a conductive material or an insulating material. An acoustic lens (not shown) is typically attached to the upper surface of the acoustic matching material 20. The acoustic lens is a lens made of silicone rubber or the like having an acoustic impedance close to that of the body. The acoustic lens focuses the ultrasonic beam.

  Hereinafter, a combination of the transducer group 10, the acoustic matching material 20, and the first substrate 30 is referred to as a transducer block 70. Next, the arrangement pattern of the transducer blocks 70 will be described.

  The shape and size of each transducer block 70, that is, the number of longitudinal and lateral transducers 50 included in each transducer block 70 may be the same or different. However, in order to reduce the side lobe of the ultrasonic beam generated by the ultrasonic probe, it is better that the pattern of the shape and size of each transducer block 70 has no regularity. Therefore, the shape and size of each transducer block 70 are designed to be different for each transducer block 70. Then, the transducer block 70 is arranged on the second substrate 40 so that the shape and size of the transducer block 70 as a whole is not regular.

  Since the second substrate 40 has a quadrangular shape, the entire vibrator block 70 has a quadrangular shape even if each of the vibrator blocks 70 has a different shape and size. Must be. Accordingly, each transducer block 70 is appropriately arranged on the second substrate 40 according to its shape and size.

  The arrangement pitch of the transducers 50 is designed to be the same in all transducer blocks 70. The interval between the two adjacent transducers 50 and the interval between the two adjacent transducer blocks 70 are designed to be the same. However, the present embodiment need not be limited to this. That is, the arrangement pitch of the transducers 50 does not have to be the same in all transducer blocks 70, and may be a different arrangement pitch for each transducer block 70, for example. Further, the interval between the two adjacent transducers 50 may be different from the interval between the two adjacent transducer blocks 70.

  Generally, the number of transducers included in an ultrasonic probe varies depending on the application of the ultrasonic probe. The number of the two-dimensional array of transducers included in the heart ultrasonic probe is, for example, about 50 vertical × 50 horizontal. Further, the number of transducers of the two-dimensional array included in the abdominal ultrasound probe is, for example, about 500 vertical x 500 horizontal.

  The number of transducers 50 included in the ultrasonic probe according to the present embodiment is also the same as that of a general one, and varies depending on the application. That is, the number of the transducers 50 included in the heart ultrasound probe is, for example, about 50 vertical × 50 horizontal. In this case, it is assumed that the vibrator unit is divided into, for example, four vibrator groups 10. The number of transducers 50 included in the abdominal ultrasound probe is, for example, about 500 vertical x 500 horizontal. In this case, the vibrator unit is divided into, for example, 100 vibrator groups 10.

  As described above, the ultrasonic probe 10 divides a transducer unit having a large aperture diameter into a plurality of transducer groups 10 having a small aperture diameter.

  Next, a method for manufacturing the ultrasonic probe 10 will be described. First, a plurality of transducer groups 10 having different shapes and sizes are formed. In addition, a plurality of acoustic matching materials 20 having substantially the same shape and size as each transducer group 10 are formed. Then, the vibrator group 10 and the acoustic matching material 20 having substantially the same shape and size are bonded with a resin or the like. A plurality of first substrates 30 having substantially the same shape and size as each transducer group 10 are formed. Then, as shown in FIG. 3, the transducer group 10 having the same shape and size as each other and the first lead so that the signal leads of the transducer group 10 and the bumps 33 on the upper surface of the first substrate 50 are bonded. The substrate 30 is bonded with resin or the like. In this way, the transducer block 70 is formed by bonding the transducer group 10, the acoustic matching material 20, and the first substrate 30. Similarly, a plurality of transducer blocks 70 are formed.

  Next, a single second substrate 40 is formed. As shown in FIG. 4, the first substrate 30 and the second substrate 40 are made of resin or the like so that the bumps 36 on the lower surface of the first substrate 30 and the signal lead pads 42 on the upper surface of the second substrate 40 are connected. Glue each. In this way, the plurality of transducer blocks 70 are bonded to the second substrate 40.

  Thereafter, the ultrasonic probe 10 is completed by performing the manufacturing process in the same manner as in the prior art.

  Next, the effect of the ultrasonic probe 10 having the above configuration will be described. Hereinafter, for simplicity of explanation, the plurality of transducer groups 10 are collectively referred to as a transducer unit. In the present embodiment, a vibrator unit having a large opening diameter is not directly connected to a single flexible wiring board (second substrate 40) having a large opening diameter, and the vibrator unit has a plurality of vibrators having a small opening diameter. After dividing into a group 10 and connecting the plurality of vibrator groups 10 to the plurality of first substrates 30 respectively, the plurality of first substrates 30 are connected to a single flexible wiring substrate (second substrate 40). Yes.

  Thus, by connecting to the flexible wiring board (second board 40) for each transducer group 10 having a small opening diameter, the electrical connection points (connection between the bump and the signal lead pad) that must be connected at one time. ) Can be reduced. Specifically, the ultrasonic probe has 25 transducer groups 10, and each transducer group 10 has 25 transducers 50. In this case, conventionally, since 625 (25 × 25) transducers 50 included in the ultrasonic probe are connected to the second substrate 40 at a time, there are 625 connection points per connection. become. However, in the case of this embodiment, each transducer block 70 is connected to the second substrate 40, so there are 25 connection locations per connection. As described above, according to the present embodiment, the number of electrical connection points in the connection between the vibrator 50 and the substrate (second substrate 40) can be significantly reduced.

  Furthermore, by reducing the number of signal leads on the lower surface as compared with the number of signal leads on the upper surface of the first substrate, it is possible to further reduce electrical connection locations.

  In addition, since the area of the first substrate 30 is small, the manufacturing yield of the first substrate 30 can be secured satisfactorily. Therefore, the manufacturing cost of the first substrate 30 can be kept low. Further, the flatness of the transducer unit divided into the plurality of transducer groups 10 is flat compared to the transducer unit not divided into the plurality of transducer groups 10. Therefore, the ultrasonic characteristics of the ultrasonic probe 10 are better than the ultrasonic characteristics of an ultrasonic probe having a conventional structure.

  Thus, according to the present embodiment, it is possible to improve the yield of an ultrasonic probe having a two-dimensional array structure.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

  For example, in the above configuration, the first substrate 30 is directly connected to each transducer group 10. However, the present embodiment need not be limited to this. For example, an acoustic braking material (backing material) may be connected to the lower surface of the transducer group 10 and the front surface of the first substrate may be connected to the lower surface of the connected acoustic braking material. In this case, the signal lead connected to the signal electrode penetrates through the inside of the acoustic braking material and is connected to the signal lead pad on the upper surface of the first substrate 30.

  In the above configuration, one acoustic matching material is provided on the upper surface of one transducer group 10. However, the present embodiment need not be limited to this. For example, the acoustic matching material may be divided in the same manner as the vibrator. That is. One acoustic matching material may be provided on the upper surface of one transducer 50.

  In the above configuration, a single acoustic matching material is provided on the upper surfaces of the plurality of transducer groups 10. However, the present embodiment need not be limited to this. For example, not only one layer but also two, three, or more acoustic matching materials may be provided on the upper surface of the plurality of transducer groups 10. In this case, the material of the acoustic matching material of each layer is determined so that the acoustic impedance from the plurality of transducer groups 10 to the subject (not shown) changes stepwise.

  In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The perspective view of the principal part of the ultrasonic probe concerning the embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. 1. The figure which shows the process of connecting the vibrator | oscillator of FIG. 1, an acoustic matching material, and a 1st board | substrate, and forming a vibrator | oscillator block. The figure which shows the process of connecting several vibrator | oscillator blocks of FIG. 1 to a single 2nd board | substrate.

  DESCRIPTION OF SYMBOLS 10 ... Vibrator group, 20 ... Acoustic matching material, 30 ... 1st board | substrate, 31 ... 1st board | substrate body, 32 ... Signal lead pad, 33 ... Bump, 34 ... Through-electrode, 35 ... Signal lead pad, 36 ... Bump, 40 ... second substrate, 41 ... second substrate body, 42 ... signal lead pad, 50 ... vibrator, 52 ... piezoelectric body, 54 ... ground electrode, 56 ... signal electrode, 60 ... resin, 70 ... vibrator block

Claims (5)

A plurality of transducer groups having a plurality of transducers arranged two-dimensionally;
A plurality of first substrates respectively electrically connected to the plurality of transducer groups;
A single second substrate electrically connected to the plurality of first substrates;
An ultrasonic probe comprising:   The ultrasonic probe according to claim 1, wherein each of the plurality of first substrates and the second substrate are printed wiring boards. Each of the plurality of first substrates is an IC substrate,
The second substrate is a printed wiring board;
The ultrasonic probe according to claim 1. Each of the plurality of first substrates is
A plurality of through holes penetrating the inside of the first substrate so as to reach an upper surface and a lower surface of the first substrate;
A plurality of metal thin films respectively provided in the plurality of through holes to electrically connect the upper surface and the lower surface;
The ultrasonic probe according to claim 1.   The number of signal leads on the connection surface between the first substrate and the second substrate is smaller than the number of signal leads on the connection surface between the transducer group and the first substrate. Item 2. The ultrasonic probe according to Item 1.

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