JP3929722B2 - Array-type ultrasonic probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an array-type ultrasonic probe (referred to as an array-type probe) in the industrial technical field, and more particularly to a method for deriving a ground wire.
[0002]
[Prior art]
BACKGROUND OF THE INVENTION An array-type probe is used as an ultrasonic wave transmission / reception source in, for example, a medical ultrasonic diagnostic apparatus. Normally, a plurality of piezoelectric elements are arranged and electronically or sectorally driven to obtain a tomographic image.
[0003]
(Example of Prior Art) FIG. 4 and FIG. 5 are diagrams of an array type probe for explaining one conventional example, FIG. 4 is a side sectional view, and FIG. 5 is a plan view.
The array-type probe is formed by arranging a plurality of piezoelectric elements 2 having upper and lower electrodes 1 (ab) on a backing material 3. An acoustic matching layer 4 that matches the acoustic impedance with the living body is formed in the central region of the piezoelectric element 2. Normally, after a piezoelectric plate is fixed on the backing material 3 and a continuous acoustic matching layer is laminated, the piezoelectric element 2 and the acoustic matching layer 4 are cut and divided.
[0004]
Then, the lead wires 5 (ab) are connected to the surfaces of both ends by soldering, and the upper surface electrode 1a is commonly connected to be ground potential. Thereafter, a filler (not shown) is embedded between each piezoelectric element 2 and the acoustic matching layer 4. Each bottom electrode 1b is connected to a staggered metal foil 6 at both ends for application of a driving voltage.
[0005]
[Problems to be solved by the invention]
(Problem of the prior art) However, in the array type probe having the above configuration, when connecting the lead wire to the upper surface electrode 1a of the piezoelectric element 2, the upper surface electrode 1a is peeled off by the heat of the solder (so-called solder erosion). There was a problem. For example, when the adhesion strength of the electrode is small like a composite piezoelectric material, it becomes a particularly significant problem. There is also a problem of thermal damage in which the piezoelectricity of the piezoelectric element 2 is impaired by the heat of the solder.
[0006]
For this reason, for example, the use of the conductive adhesive 7 instead of solder has been considered. However, in this case, there is a problem that the conductive adhesive 7 enters the grooves between the piezoelectric elements 2 and electrically connects the upper and lower electrodes 1 (ab) (FIG. 6). In the case of solder, it does not enter a portion where there is no electrode.
[0007]
In addition, it has been considered that the lead wire 5 (ab) is connected after the filler is embedded in the groove between the piezoelectric elements 2, but in this case, the filler adheres to the surfaces of both ends of the piezoelectric element 2. There was a problem of impairing electrical continuity.
[0008]
(Object of the Invention) An object of the present invention is to provide an array type probe which prevents thermal damage to the upper surface electrode and the piezoelectric element.
[0009]
[Means for Solving the Problems]
According to the present invention, as shown in the scope of the claims, a plurality of piezoelectric elements having electrodes on both main surfaces are arranged on a backing material, an acoustic matching layer is provided in the central region, and the end surface of the piezoelectric element is provided. In the array-type ultrasonic probe that is electrically connected in common and has a ground potential surface, a metal foil that is independent for each of the plurality of piezoelectric elements is formed on the end surface of the plurality of piezoelectric elements by a conductive adhesive. The metal foil that is bonded and bonded independently for each of the plurality of piezoelectric elements has a configuration in which lead wires are commonly connected by solder .
[0010]
[Action]
In the present invention, a metal foil is bonded to the end surface of the piezoelectric element by a conductive adhesive to connect the lead wires in common. Therefore, the conductive adhesive blocks the heat of the solder and reduces heat transfer to the upper surface electrode and the piezoelectric element. Further, since soldering is not performed directly on the electrodes of the piezoelectric element, no solder erosion occurs. An embodiment of the present invention will be described below.
[0011]
【Example】
FIGS. 1 and 2 are views of an array type probe for explaining an embodiment of the present invention. FIG. 1 is a side sectional view and FIG. 2 is a partial front sectional view. In addition, description of the same part as a prior art example is simplified or abbreviate | omitted.
As described above, the array type probe has a plurality of piezoelectric elements 2 having the upper and lower electrodes 1 (ab) arranged on the backing material 3, an acoustic matching layer 4 is formed in the central region, and the lower electrode 1 b The electrode-leading metal foil 6 is connected to both ends in a staggered manner.
[0012]
In this embodiment, the piezoelectric plate and the continuous acoustic matching layer 4 are fixed on the backing material 3, and then the continuous metal foil is fixed to the both end surfaces of the upper surface electrode 1 a with the conductive adhesive 7. Next, the metal foil and the conductive adhesive 7 are cut together with the piezoelectric plate and the continuous acoustic matching layer to obtain the metal foil 8 fixed by the individual piezoelectric elements 2, the acoustic matching layer 4 and the conductive adhesive 7. Then, the lead wire 5 (ab) is commonly connected to both ends of the upper surface electrode 1a by solder (not shown) to obtain a ground potential. Then, a filler (not shown) is buried between the grooves.
[0013]
With such a configuration, the conductive adhesive 7 and the metal foil 8 are interposed between the upper surface electrode 1a of the piezoelectric element 2 and the solder. Therefore, the solder does not directly contact the upper surface electrode 1 a and the solder heat is absorbed and blocked by the resin component (heat capacity) of the conductive adhesive 7. This prevents electrode peeling without causing solder erosion. Then, heat transfer to the piezoelectric element 2 is reduced to maintain good piezoelectricity. For these reasons, the upper surface electrode 1a and the piezoelectric element 2 are prevented from being thermally damaged by the solder heat.
[0014]
[Second embodiment]
FIG. 3 is a side sectional view of an array type probe for explaining another embodiment of the present invention. The description of the same parts as those in the previous embodiment is omitted.
In this embodiment, the metal foil 8 is connected by the conductive adhesive 7 so as to protrude from both ends of the piezoelectric element 2. An insulating adhesive 9 is provided on the lower surface of the protruding portion of the metal foil 8 to fix the protruding portion. Then, the lead wire 5 (ab) is connected to the protruding portion by a conductive adhesive (not shown), and the upper surface electrodes 1a are electrically connected in common.
[0015]
In such a case, since the lead wire 5 (ab) is connected on the protruding portion of the metal foil 8, the conductive adhesive does not enter between the grooves of each piezoelectric element 2. And since it connects by a conductive adhesive, it can join at low temperature rather than solder. Therefore, thermal damage to the upper surface electrode 1a and the piezoelectric element 2 can be further reduced.
[0016]
In addition, you may connect using not only a conductive adhesive but solder. Even in this case, since the lead wire 5 (ab) is disconnected from the upper surface electrode 1a and connected, and the heat capacity of the insulating adhesive 9 is added to prevent heat transfer, thermal damage can be further reduced.
[0017]
[Other matters]
In each of the above embodiments, the lead wires 5 (ab) are disposed on the surfaces of both ends of the piezoelectric element 2, but may be the surfaces of one end. In this case, the acoustic matching layer 4 can be formed on the entire surface excluding the surface of one end. Moreover, although the lower surface electrode 1b was derived | led-out from the both ends by the metal foil 6, it is good also as derived | led-out only from the one end part. Further, although the piezoelectric elements 2 are arranged on a plane, those arranged on a curved surface can also be applied.
[0018]
【The invention's effect】
In the present invention, a plurality of piezoelectric elements having electrodes on both main surfaces are arranged on a backing material, an acoustic matching layer is provided in the central region, and the end surfaces of the piezoelectric elements are electrically connected in common to form a ground potential surface. In the array-type ultrasonic probe, a metal foil independent for each of the plurality of piezoelectric elements is bonded to an end surface of each of the plurality of piezoelectric elements by a conductive adhesive, and each of the plurality of piezoelectric elements is independent. Since the lead wires are commonly connected to the metal foils joined together by soldering, it is possible to provide an array-type probe that prevents thermal damage to the top electrode and the piezoelectric element.
[Brief description of the drawings]
FIG. 1 is a side sectional view of an array type probe for explaining an embodiment of the present invention.
FIG. 2 is a partial front sectional view of an array type probe for explaining an embodiment of the present invention.
FIG. 3 is a side sectional view of an array type probe for explaining another embodiment of the present invention.
FIG. 4 is a side sectional view of an array type probe for explaining a conventional example.
FIG. 5 is a plan view of an array type probe for explaining a conventional example.
FIG. 6 is a partial front sectional view of an array-type probe for explaining a conventional example.
[Explanation of symbols]
1 electrode, 2 piezoelectric element, 3 backing material, 4 acoustic matching layer, 5 lead wire, 6, 8 metal foil, 7 conductive adhesive, 9 insulating adhesive.

Claims (1)

A plurality of piezoelectric elements having electrodes on both main surfaces are arranged on a backing material, an acoustic matching layer is provided in the central region, and the end surfaces of the piezoelectric elements are electrically connected in common to form a ground potential surface. In the acoustic probe, an independent metal foil for each of the plurality of piezoelectric elements is bonded to the end surface of each of the plurality of piezoelectric elements by a conductive adhesive, and each of the plurality of piezoelectric elements is bonded independently. An ultrasonic probe characterized in that lead wires are commonly connected to the metal foil by solder .

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