JP3612312B2 - Ultrasonic probe and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic probe and a method for manufacturing the same, and more particularly to an ultrasonic probe including a backing with a built-in lead array and a method for manufacturing the same.
[0002]
[Prior art]
For example, in a 2D array vibrator composed of a plurality of vibration elements, a backing with a built-in lead array is used to connect a lead (signal lead) to each vibration element (see, for example, Japanese Patent No. 3279375). Here, a plurality of electrode pads connected to a plurality of leads are formed on the upper and lower surfaces of the backing. Each electrode pad on the upper surface is bonded to the electrode surface (lower surface) of each piezoelectric element. Thereby, each lead is electrically connected to each piezoelectric element.
[0003]
Conventionally, a matching layer is provided on the front side of each piezoelectric element. This is because the acoustic impedance of the piezoelectric element and the acoustic impedance of the living body are matched. On the other hand, it has also been proposed to provide a back intermediate layer on the back side of each piezoelectric element. Here, it is considered that the back surface intermediate layer can function as a back side matching layer or a back side reflection layer depending on its characteristics.
[0004]
[Problems to be solved by the invention]
However, if the back intermediate layer is provided, the plurality of leads provided in the backing cannot be electrically connected to each piezoelectric element as it is. Moreover, a rational manufacturing process for providing such a back intermediate layer is required.
[0005]
An object of the present invention is to enable a lead to be reliably connected to each piezoelectric element even when a back surface intermediate layer is provided.
[0006]
Another object of the present invention is to provide a process for manufacturing an ultrasonic probe having a plurality of back surface intermediate layers and a backing with a built-in lead array.
[0007]
[Means for Solving the Problems]
(1) In order to achieve the above object, the present invention is provided with a plurality of piezoelectric elements and a back side of the plurality of piezoelectric elements, and absorbs ultrasonic waves radiated from the plurality of piezoelectric elements to the back side. Backing, a plurality of back intermediate layers provided between the plurality of piezoelectric elements and the backing, and electrically connected to the plurality of piezoelectric elements through the backing and the plurality of back intermediate layers seen including a plurality of leads, wherein the in plurality of rear intermediate layer, a plurality of dividing grooves separating the adjacent rear intermediate layer each other forming said each piezoelectric element, the rear intermediate layer is provided separated characterized in that was.
[0008]
According to the above configuration, a plurality of leads are provided through the backing and the plurality of back surface intermediate layers, whereby a signal can be supplied to each piezoelectric element or a ground can be connected. The present invention can be applied to various array transducers such as a 1D array transducer, a 1.5D array transducer, and a 2D array transducer (including a sparse array transducer).
[0009]
Preferably, each of the leads includes a first lead portion inserted into the backing and a second lead portion inserted into the back intermediate layer, and the first lead portion and the second lead. The part consists of one conductor. According to this configuration, it is not necessary to connect the first lead portion and the second lead portion.
[0010]
Desirably, when the acoustic impedance of each piezoelectric element is Z1, the acoustic impedance of each back intermediate layer is Z2, and the acoustic impedance of the backing is Z3,
Z1>Z2> Z3 (1)
Thus, each of the back intermediate layers functions as a back side matching layer.
[0011]
According to this configuration, the back surface intermediate layer functions as a matching layer that matches the acoustic impedance, that is, it is possible to further enhance the action of absorbing ultrasonic waves in the backing.
[0012]
Desirably, when the acoustic impedance of each piezoelectric element is Z1, the acoustic impedance of each back intermediate layer is Z2, and the acoustic impedance of the backing is Z3,
Z1>Z3> Z2 (2)
Thus, each of the back intermediate layers functions as a back side reflective layer.
[0013]
According to this configuration, the back surface intermediate layer functions as a reflective layer that positively utilizes the difference in acoustic impedance. That is, it is possible to increase the sound pressure of the ultrasonic wave radiated forward from the piezoelectric element by reflecting a part of the ultrasonic wave radiated to the back side forward. In any case, in order for the back surface intermediate layer to function as a matching layer or a reflective layer, it is desirable to make the thickness appropriate in relation to the wavelength of the ultrasonic wave.
[0014]
Desirably, each said back surface intermediate layer is comprised with an electroconductive member, and each said back surface intermediate layer serves as an electrode pad of each said piezoelectric element. According to this configuration, since it is not necessary to separately provide an electrode pad for each piezoelectric element, the structure can be simplified and the manufacturing cost can be reduced.
[0015]
(2) Further, the present invention provides a plurality of piezoelectric elements, a backing provided on the back side of the plurality of piezoelectric elements, for absorbing ultrasonic waves radiated from the plurality of piezoelectric elements to the back side, and the plurality of the plurality of piezoelectric elements . a plurality of rear intermediate layer functioning as an electrode pad provided between the piezoelectric element and the backing, saw including a plurality of leads electrically connected to the plurality of rear intermediate layer, the plurality of back In the intermediate layer, a plurality of dividing grooves for separating adjacent back surface intermediate layers from each other are formed, and a separate back surface intermediate layer is provided for each of the piezoelectric elements .
[0016]
In the above configuration, each lead may penetrate both the backing and each back surface intermediate layer, or may penetrate only the backing and be electrically connected to the bottom surface of each back surface intermediate layer. In any case, each lead is electrically connected to each back intermediate layer.
[0017]
(3) The present invention also includes a step of passing a plurality of conductive wires between the back surface intermediate member and the substrate, a step of providing a backing between the back surface intermediate member and the substrate, and an upper surface of the back surface intermediate member. a step of providing a piezoelectric member on the side, and cutting the piezoelectric member and the rear intermediate member, thereby, viewed including the steps of forming a plurality of piezoelectric elements and a plurality of rear intermediate layer, a by the cutting, each A separate back surface intermediate layer is formed for each piezoelectric element .
[0018]
According to the above configuration, the backing is formed in a state where a plurality of conductive wires are stretched between the back intermediate member and the substrate, and the piezoelectric member and the back intermediate member are cut together. Each back intermediate layer desirably has an insulating property.
[0019]
Preferably, the method includes a step of providing an electrode member on an upper surface of the back intermediate member between the step of providing the backing and the step of providing the piezoelectric member, and by cutting, the plurality of piezoelectric elements, the plurality of electrode pads, and The plurality of back surface intermediate layers are formed.
[0020]
Preferably, in the step of providing the backing, a fluid backing material is filled between the back intermediate member and the substrate and is cured, and at this time, the back intermediate member and the substrate are separated from each other. It functions as a positioning member for the plurality of conductive wires. According to this structure, positioning of each conducting wire can be performed simply.
[0021]
Preferably, a plurality of through holes are formed in the back intermediate member in advance, and the conductive wires are inserted through the through holes.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is a flowchart showing the main part of the manufacturing process of the ultrasonic probe according to the present invention. Hereinafter, the manufacturing process will be described with reference to the drawings, and the structural features of the ultrasonic transducer included in the ultrasonic probe according to the present embodiment will also be described.
[0024]
The ultrasonic probe according to the present embodiment is connected to the ultrasonic diagnostic apparatus main body via a cable. Further, in use, it is used in contact with the body surface of a living body, and ultrasonic waves are transmitted and received in that state. Of course, the ultrasonic probe according to the present embodiment may be inserted into a body cavity.
[0025]
The process of S101 shown in FIG. 1 will be described. In FIG. 2, the back intermediate member 10 and the substrate 12 are positioned at a predetermined interval. Here, the back surface intermediate member 10 is a member for forming a back surface intermediate layer for each vibration element, and the back surface intermediate member 10 is configured as a plate-like member in the example shown in FIG. The back intermediate member 10 can be made of, for example, a material obtained by mixing an inorganic powder or the like with an epoxy resin. The back intermediate member 10 is formed with a plurality of through holes 10A corresponding to the two-dimensional array of vibration elements. The through-hole 10A can be formed by using, for example, laser processing or an ultrafine drill. In the example shown in FIG. 2, the back intermediate member 10 is a member having an insulating property, but it may be formed of a conductive member as will be described later. The thickness of the back intermediate member 10 is set in relation to the wavelength of the ultrasonic wave, and preferably the thickness is set to an odd multiple of a quarter wavelength.
[0026]
The substrate 12 described above is configured as a plate-like member having an insulating property. In addition, a plurality of through holes 12 </ b> A are formed in the substrate 12 in the same arrangement as the plurality of through holes 10 </ b> A formed in the back intermediate member 10. Of course, a plurality of through holes 12A may be formed in the substrate 12 in an arrangement different from that of the plurality of through holes 10A formed in the back intermediate member 10. A plurality of electrode pads 14 are provided on the back side of the substrate 12, that is, the lower surface side in the drawing, corresponding to the plurality of through holes 12A. The electrode pad 14 is made of a conductive member. A through hole 14A is formed at the center of each electrode pad 14, and each through hole 12A formed in the substrate 12 and each through hole 14A formed in the electrode pad 14 communicate with each other.
[0027]
In the step of S101 shown in FIG. 1, as shown in FIG. 2, in the state where the back intermediate member 10 and the substrate 12 are positioned at a predetermined interval, a plurality of conductive wires 18 are stretched between them. Specifically, one end side of the conducting wire 18 is pierced through each through hole 10A formed in the back intermediate member 10, and the other end side of the conducting wire 18 is pierced through each through hole 12A (and the through hole 14A) of the substrate 12. Passed.
[0028]
Then, for example, soldering or the like is performed on the through-hole 14A of each electrode pad 14, and then a portion of each conductive wire 18 drawn downward from the electrode pad 14 is cut. FIG. 2 shows this state, and reference numeral 16 indicates a soldered portion. Of course, the cutting of the drawn portion of the conducting wire 18 may be performed in a later step.
[0029]
In S102 of FIG. 1, the space 20 between the back intermediate member 10 and the substrate 12 shown in FIG. 2 is surrounded by a frame body (not shown), and the space 20 is filled with the backing material. In FIG. 2, the positioning member that holds the back intermediate member 10 and the substrate 12 is not shown.
[0030]
In FIG. 2, the through-hole 10A, the through-hole 12A, and the through-hole 14A are shown large for understanding the invention, but in actuality, the diameters of the through-holes 10A, 12A, and 14A are the conductors 18. It is set to be slightly larger than the diameter of. The through holes 10A, 12A, and 14A are not shown in FIGS. 3 and 4 later.
[0031]
Here, the backing material will be described. In the present embodiment, as the backing material, for example, a material obtained by mixing tungsten powder or the like into an epoxy resin can be used. Here, the purpose of mixing tungsten powder or the like into the epoxy resin is to obtain a desired acoustic impedance and a desired attenuation factor. In the above-described S102, after vacuum deaeration of the filled backing material, the backing material is allowed to stand, for example, at 80 ° C. for 5 hours to cure the backing material. Then, the backing material is processed so as to obtain a predetermined outer shape.
[0032]
In S103 of FIG. 1, the electrode member 24 is formed on the upper surface of the back intermediate member 10, as shown in FIG. The electrode member 24 is configured as a plate-like member in the example shown in FIG. 3, but an electrode member 24, that is, an electrode pad may be provided for each vibration element at this stage. The electrode member 24 can be formed using techniques such as electroless plating, vapor deposition, sputtering, and application of conductive paint.
[0033]
As shown in FIG. 3, the electrode member 24 is electrically connected to the upper end of the conductive wire 18 that later functions as a signal lead. Each conductor 18 is roughly divided into a first portion 18A and a second portion 18B. The first portion 18A is inserted through the backing 22, and the second portion 18B is inserted through the back intermediate member 10. . Compared with the case where the conductors are individually buried for each of these portions, the present embodiment has an advantage that the conductors can be collectively provided for both the back intermediate member 10 and the backing 22. .
[0034]
In step S104 shown in FIG. 1, a plate-like piezoelectric member (piezoelectric plate) is bonded to the upper surface of the block body shown in FIG. In this case, for example, a conductive adhesive or a nonconductive adhesive is used. As will be described later, the piezoelectric member has a lower electrode layer that functions as a signal electrode and an upper electrode layer that functions as a ground electrode. These electrode layers can be formed into a film shape by using, for example, vapor deposition or sputtering.
[0035]
Next, in the process of S105 in FIG. 1, a plurality of divided grooves are formed in a matrix shape along the vertical direction and the horizontal direction from the upper surface side of the processed body after the piezoelectric member is bonded.
[0036]
Due to the formation of the dividing grooves, the back surface intermediate member 10 is divided into a plurality of back surface intermediate layers, and the electrode member 24 shown in FIG. 3 is also divided into a plurality of electrode pads. Furthermore, the piezoelectric member described above is also divided into a plurality of piezoelectric elements.
[0037]
In S106 of FIG. 1, ground leads are provided on the upper surface side of the plurality of piezoelectric elements. The ground lead is formed of, for example, a copper foil having a planar shape. An upper electrode layer provided on each piezoelectric element is electrically connected to the ground lead. Thereafter, a plate-like alignment member is bonded to the upper surface side of the ground lead. In step S107, the alignment member is divided into matrixes along the vertical and horizontal directions, thereby forming a plurality of matching layers corresponding to the plurality of vibration elements. Become.
[0038]
FIG. 4 shows a state after the process of S107 is executed. In the above-described step S105, for example, the dividing groove 100 is formed using a dicing saw or the like, and in the above-described step S107, the dividing groove 102 is formed using a dicing saw or the like as described above. Looking at each vibration element, the back surface intermediate layer 10B is provided on the upper surface side of the backing 22, and the electrode pad 24A is formed on the upper surface side thereof. A piezoelectric element 26 is provided on the upper surface side of the electrode pad 24A. The lower electrode layer 26B of the piezoelectric element 26 is electrically connected to the electrode pad 24A. A ground lead 28 is provided on the upper surface side of the piezoelectric element 26, and the ground lead 28 is electrically connected to the upper surface electrode layer 24 </ b> A of the piezoelectric element 26. A matching layer 30 is provided on the upper surface side of the ground lead 28. As is clear from the above description and as shown in the drawing, each separation groove 100 formed vertically from above has a depth that exceeds the thickness of the back intermediate member 10 and enters the backing 22. Thus, each back surface intermediate layer 10B is separated from other back surface intermediate layers 10B.
[0039]
That is, by executing the above steps, for example, a 2D array transducer can be configured. The above split groove 100 functions as a groove for each vibrating element (and the rear intermediate layer) electrically and acoustically separated from each other between the respective oscillation Domoto child (and the rear intermediate layers), the separation The groove 100 may be filled with a member having electrical and acoustic isolation as required. The same applies to the dividing groove 102.
[0040]
Next, the function of each back surface intermediate layer 10B will be described. The acoustic impedance of the piezoelectric element 26 is Z1, the acoustic impedance of each back surface intermediate layer 10B is Z2, and the acoustic impedance of the backing 22 is Z3.
[0041]
In this case, when each back surface intermediate layer 10B functions as a back side matching layer, each acoustic impedance is set so that the relationship of Z1>Z2> Z3 is satisfied.
[0042]
On the other hand, when each back surface intermediate layer 10B functions as a back side reflection layer, the acoustic impedance of each member is set so that the relationship of Z1>Z3> Z2 is established.
[0043]
When each back surface intermediate layer 10B functions as a back surface side matching layer, it is possible to further enhance the action of absorbing unnecessary ultrasonic waves in the backing 22, while when each back surface intermediate layer 10B functions as a back surface side reflective layer. It is possible to further increase the sound pressure of the ultrasonic wave radiated forward. In order to produce such an effect more, it is desirable to set the thickness of the back intermediate layer 10B to an odd multiple of 1/4 of the ultrasonic wavelength.
[0044]
FIG. 5 shows a main configuration of another embodiment. In this embodiment, a conductive member is used as the back intermediate layer 30. The lead 18 includes a first portion 18A inserted into the backing and a second portion 18B inserted through the back surface intermediate layer 30. Since the back intermediate layer 30 is made of a conductive member, the electrode pad 24A shown in FIG. 4 and the like can be eliminated, and the structure can be simplified correspondingly, and the manufacturing process can be simplified. There is.
[0045]
FIG. 6 shows still another embodiment. In the configuration example shown in FIG. 6, the conductive back intermediate layer 30 is used as in the example shown in FIG. The upper end of 18 reaches only the lower surface level of the back surface intermediate layer 30 and does not penetrate the entire back surface intermediate layer 30.
[0046]
When the backing 22 is made of a conductive member, it is desirable to provide an insulating coating layer on the outside of the conductor.
[0047]
Note that the through hole 10A shown in FIG. 2 may be filled and cured with the same member as the back intermediate member 10, and similarly, the through hole 12A in the substrate 12 is similar to the substrate 12 as well. The member may be filled and cured. Furthermore, in the present embodiment, only one back surface intermediate layer is provided, but a configuration in which a plurality of back surface intermediate layers are stacked may be employed. In this case, the acoustic impedance of each layer may be varied stepwise. In that case, it is desirable that the thickness of each layer is an odd multiple of 1/4 of the wavelength of the ultrasonic wave.
[0048]
【The invention's effect】
As described above, according to the present invention, the lead can be reliably connected to each piezoelectric element even when the back surface intermediate layer is provided. In addition, according to the present invention, it is possible to provide a manufacturing process of an ultrasonic probe having a plurality of back surface intermediate layers and a lead array built-in backing.
[Brief description of the drawings]
FIG. 1 is a flow for explaining a manufacturing process of an ultrasonic probe according to the present invention.
FIG. 2 is a diagram for explaining a process of inserting a conducting wire.
FIG. 3 is a view for explaining a step of forming an electrode member.
FIG. 4 is a diagram showing a finally formed two-dimensional array transducer.
FIG. 5 is a diagram showing a configuration of another embodiment.
FIG. 6 is a diagram showing a configuration of still another embodiment.
[Explanation of symbols]
10 Back intermediate member, 12 Substrate, 14 Electrode pad, 18 Conductor, 22 Backing, 24 Electrode member, 26 Piezoelectric element, 28 Ground lead, 100, 102 Dividing groove.

Claims (10)

A plurality of piezoelectric elements;
A backing that is provided on the back side of the plurality of piezoelectric elements and absorbs ultrasonic waves radiated from the plurality of piezoelectric elements to the back side;
A plurality of back intermediate layers provided between the plurality of piezoelectric elements and the backing;
A plurality of leads electrically connected to the plurality of piezoelectric elements through the backing and the plurality of backside intermediate layers;
Only including,
In the plurality of back surface intermediate layers, a plurality of dividing grooves that separate adjacent back surface intermediate layers from each other are formed,
An ultrasonic probe, wherein a separate back surface intermediate layer is provided for each of the piezoelectric elements . The ultrasonic probe according to claim 1,
Each lead is
A first lead portion inserted through the backing;
A second lead portion inserted through each back intermediate layer;
Consists of
The ultrasonic probe according to claim 1, wherein the first lead portion and the second lead portion are formed of a single conductor. The ultrasonic probe according to claim 1,
When the acoustic impedance of each piezoelectric element is Z1, the acoustic impedance of each back intermediate layer is Z2, and the acoustic impedance of the backing is Z3, the relationship Z1>Z2> Z3 holds,
The ultrasonic probe according to claim 1, wherein each of the back intermediate layers functions as a back matching layer. The ultrasonic probe according to claim 1,
When the acoustic impedance of each piezoelectric element is Z1, the acoustic impedance of each back intermediate layer is Z2, and the acoustic impedance of the backing is Z3, the relationship of Z1>Z3> Z2 holds,
Each of the back intermediate layers functions as a back side reflection layer. The ultrasonic probe according to claim 1,
Each back intermediate layer is composed of a conductive member,
The ultrasonic probe, wherein each of the back surface intermediate layers is also used as an electrode pad of each of the piezoelectric elements. A plurality of piezoelectric elements;
A backing that is provided on the back side of the plurality of piezoelectric elements and absorbs ultrasonic waves radiated from the plurality of piezoelectric elements to the back side;
A plurality of back intermediate layers functioning as electrode pads provided between the plurality of piezoelectric elements and the backing;
A plurality of leads electrically connected to the plurality of back intermediate layers;
Only including,
In the plurality of back surface intermediate layers, a plurality of dividing grooves that separate adjacent back surface intermediate layers from each other are formed,
An ultrasonic probe, wherein a separate back surface intermediate layer is provided for each of the piezoelectric elements . Spanning a plurality of conductors between the back intermediate member and the substrate;
Providing a backing between the back intermediate member and the substrate;
Providing a piezoelectric member on the upper surface side of the back intermediate member;
Cutting the piezoelectric member and the back intermediate member, thereby forming a plurality of piezoelectric elements and a plurality of back intermediate layers;
Only including,
A method of manufacturing an ultrasonic probe , wherein a separate back surface intermediate layer is formed for each piezoelectric element by the cutting . In the manufacturing method of Claim 7,
A step of providing an electrode member on the upper surface of the back surface intermediate layer between the step of providing the backing and the step of providing the piezoelectric member;
The method of manufacturing an ultrasonic probe, wherein the plurality of piezoelectric elements, a plurality of electrode pads, and the plurality of back intermediate layers are formed by the cutting. The manufacturing method according to claim 8, wherein
In the step of providing the backing, a fluid backing material is filled between the back intermediate member and the substrate, and it is cured,
In that case, the said back surface intermediate member and the said board | substrate function as a positioning member of these conducting wires, The manufacturing method of the ultrasonic probe characterized by the above-mentioned. In the manufacturing method of Claim 9,
A plurality of through holes are formed in advance in the back intermediate member,
The method of manufacturing an ultrasonic probe, wherein the conductive wires are inserted into the through holes.

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