JP2002354591A - Array type ultrasonic probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an array type ultrasonic probe in which a thermal damage of an upper surface electrode and a piezoelectric element is prevented. SOLUTION: The array type ultrasonic probe comprises an acoustic matching layer at a central region by aligning the piezoelectric elements each having electrodes on both main surfaces on a backing material, in such a manner that end faces of the elements are electrically connected to a ground potential surface. The probe further comprises metal foils connected to the end surfaces via a conductive adhesive, and lead wires commonly connected to the foils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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 extracting a ground wire.

[0002]

2. Description of the Related Art An array type probe is used as a transmitting / receiving source of ultrasonic waves in, for example, a medical ultrasonic diagnostic apparatus. Normally, a plurality of piezoelectric elements are arranged and electronically driven in a sector or linear manner to obtain a tomographic image.

(Example of Prior Art) FIGS. 4 and 5 are views of an array type probe for explaining a conventional example, FIG. 4 is a side sectional view, and FIG. 5 is a plan view. The array type probe has a plurality of piezoelectric elements 2 having upper and lower electrodes 1 (ab) arranged on a backing material 3. In a central region of the piezoelectric element 2, an acoustic matching layer 4 for matching acoustic impedance with a living body is formed. Normally, after a piezoelectric plate is fixed on the backing material 3 and a continuous acoustic matching layer is laminated, it is cut and divided into individual piezoelectric elements 2 and acoustic matching layers 4.

[0004] Lead wires 5 (ab) are connected to the surfaces of both ends by soldering, respectively, and the upper electrode 1a is commonly connected to a ground potential. After that, a filler (not shown) is embedded between each piezoelectric element 2 and the acoustic matching layer 4. In addition, a metal foil 6 for electrode derivation is connected to both lower ends of the lower surface electrode 1b in a staggered manner, and a drive voltage is applied.

[0005]

(Problems to be Solved by the Invention)
However, in the array-type probe having the above-described configuration, there is a problem that when connecting a lead wire to the upper surface electrode 1a of the piezoelectric element 2, the upper surface electrode 1a is peeled off by solder heat (so-called solder erosion). For example, when the adhesion strength of the electrode is small as in the case of a composite piezoelectric material, the problem becomes particularly remarkable. Further, there is a problem of thermal damage in which the piezoelectricity of the piezoelectric element 2 is impaired by the heat of the solder.

For this reason, for example, 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 penetrates into the groove between the piezoelectric elements 2 to electrically connect the upper and lower electrodes 1 (ab) (the sixth electrode).
Figure). In the case of solder, it does not penetrate into a part without an electrode.

Further, it has been considered that the lead wire 5 (ab) is connected after the filling material is buried in the groove between the piezoelectric elements 2. In this case, the filling material is provided on both end surfaces of the piezoelectric element 2. There is a problem that the electric conduction is lost due to adhesion.

(Object of the Invention) It is an object of the present invention to provide an array type probe in which the upper electrode and the piezoelectric element are prevented from being thermally damaged.

[0009]

According to the present invention, a basic solution is to connect a metal foil to an end surface of a piezoelectric element with a conductive adhesive and commonly connect a lead wire to the metal foil. .

[0010]

According to the present invention, a metal foil is bonded to the end surface of the piezoelectric element with a conductive adhesive to connect the lead wires in common. Therefore, the conductive adhesive blocks the heat of the solder,
Heat transfer to the upper electrode and the piezoelectric element is reduced. In addition, since soldering is not directly performed on the electrodes of the piezoelectric element, solder erosion does not occur. Hereinafter, an embodiment of the present invention will be described.

[0011]

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 sectional view. The description of the same parts as those in the conventional example is simplified or omitted. As described above, the array-type probe includes a plurality of piezoelectric elements 2 having upper and lower electrodes 1 (ab) arranged side by side on a backing material 3, an acoustic matching layer 4 formed in a central area, and a lower electrode 1b formed on a lower electrode 1b. The metal foil 6 for leading out the electrodes is connected at both ends in a staggered manner.

In this embodiment, the backing material 3
After the piezoelectric plate and the continuous acoustic matching layer 4 are fixed thereon, a continuous metal foil is fixed to 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 a metal foil 8 fixed by the individual piezoelectric elements 2, the acoustic matching layer 4 and the conductive adhesive 7. Then, the upper surface electrode 1a
Lead wires 5 (ab) are commonly connected to both ends by solder (not shown) to set the ground potential. Then, a filler (not shown) is embedded between the grooves.

With such a configuration, the conductive adhesive 7 and the metal foil 8 are interposed between the upper electrode 1a of the piezoelectric element 2 and the solder. Therefore, the solder does not directly contact the upper electrode 1a, and the solder heat is absorbed and cut off 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, thermal damage to the upper surface electrode 1a and the piezoelectric element 2 due to solder heat is prevented.

[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 in the previous embodiment is omitted. In this embodiment, the piezoelectric element 2
The metal foils 8 protruding from both end portions are connected by a conductive adhesive 7. An insulating adhesive 9 is applied to the lower surface of the protruding portion of the metal foil 8.
To fix the protrusion. Then, the lead wire 5 (ab) is connected to the protruding portion by a conductive adhesive (not shown), and the upper surface electrodes 1 a are electrically connected in common.

In such a case, since the lead wire 5 (ab) is connected to the protruding portion of the metal foil 8, the conductive adhesive does not enter between the grooves of each piezoelectric element 2. Since the connection is made by the conductive adhesive, the bonding can be performed at a lower temperature than the solder. Therefore, thermal damage to the upper surface electrode 1a and the piezoelectric element 2 can be further reduced.

The connection may be made using not only a conductive adhesive but also solder. Even in this case, the lead wire 5 (ab)
Are separated from the upper surface electrode 1a and connected, and the heat capacity of the insulating adhesive 9 is added to prevent heat transfer, so that thermal damage can be further reduced.

[0017]

[Other Matters] In each of the above embodiments, the lead wires 5 (ab) are provided on both end surfaces of the piezoelectric element 2, but may be provided on one end surface. In this case, the acoustic matching layer 4 can be formed on the entire surface except the surface at one end. Further, although the lower surface electrode 1b is led out from both ends in a staggered manner by the metal foil 6, it may be led out only from one end. Further, the piezoelectric elements 2 are arranged on a plane, but those arranged on a curved surface can also be applied.

[0018]

According to the present invention, a metal foil is joined to the end surface of the piezoelectric element by a conductive adhesive and a lead wire is commonly connected to the metal foil, thereby preventing the upper electrode and the piezoelectric element from being thermally damaged. An array type probe can be provided.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an array type probe for explaining one embodiment of the present invention.

FIG. 2 is a partial front sectional view of an array type probe for explaining one 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 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)

[Claims] 1. An array type in which piezoelectric elements having electrodes on both main surfaces are arranged on a backing material, an acoustic matching layer is provided in a central region, and end surfaces of the piezoelectric elements are electrically connected to form a ground potential surface. The ultrasonic probe according to claim 1, wherein a metal foil is bonded to the end surface by a conductive adhesive, and a lead wire is commonly connected to the metal foil.