JPH02195946A - Manufacture of ultrasonic vibrator - Google Patents

Abstract

PURPOSE:To efficiently perform the electrode lead guiding work and precisely stabilize vibrator control by connecting an unsplit piezoelectric material and a flexible PC board, stabilizing the relative position of constituting elements, and applying cutting treatment for insulating vibrating elements together. CONSTITUTION:A conducting foil material 12 is stuck on one face of a flexible PC board 10, and the portion of the flexible PC board 10 removed by etching treatment on one end side of the conducting foil material 12 is an insulating region 10a. The flexible PC board 10 is connected to an unsplit block-shaped piezoelectric material 16 stuck with an electrode 14 in advance. Part of the pattern common section 10c of the flexible PC board 10 cut on the piezoelectric material and connected to the electrode 14 is notched, and its pitch is made coincident with the strip-shaped pitch removed with the conducting foil material of the pattern split section 10b of the flexible PC board 10. The portion left in the common state between the insulating section tip of the pattern split section 10b is cut, and vibrating elements 16a are separated from the conductive state and insulated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling an ultrasonic transducer, and particularly to an improvement in a method for leading out electrode leads from a transducer array in which a piezoelectric plate is finely divided into a plurality of pieces.

[Conventional technology] High-frequency mechanical vibration waves are sent into the body from the surface of the body,
Ultrasonic transducers that convert ultrasound waves returned from inside a living body into electrical signals according to the living body's reaction to these vibration waves are well known, and play an extremely important role in determining the performance of ultrasound diagnostic equipment.

Ultrasonic transducers utilize the piezoelectric effect of piezoelectric ceramics and polymeric piezoelectric materials to excitedly transmit ultrasonic waves that correspond to electrical signals applied to them), and also transmit ultrasonic waves that are returned from the living body due to the piezoelectric reverse effect. Generates an electrical signal corresponding to (wave reception).

By the way, a vibrator used in an electronic scanning ultrasonic diagnostic device is generally made up of dozens to hundreds of vibrating elements each having a minute width (=0.5 to 1.5 aa+) in which a piezoelectric plate is finely cut and divided. It is configured as a vibrator array. Ultrasonic waves drive several to dozens of elements simultaneously, and by moving the driving parts sequentially and electrically at high speed (15 to 30 frames/second), real-time images can be obtained. can.

Here, as is well known, the ultrasonic transducer is excited by applying a voltage between a pair of electrodes bonded to face each other so as to sandwich the transducer. Therefore, in the case of an array type vibrator consisting of a large number of vibrating elements as described above, electrode leads must be derived for each vibrating element.

However, the pitch between the vibrating elements in such an array probe is extremely small as described above, and it is extremely difficult to attach individual electrode leads to each vibrating element.

Conventional methods for attaching electrode leads to array probes include, for example, manually adhering lead wires, or using a flexible PC board with a pattern printed in advance by etching or the like in accordance with the pitch of the vibrating elements. Common.

[Problems to be Solved by the Invention] However, in the method using the lead wire, since the electrode surface of the vibrator is unsuitable for wire bonding,
It is not easy to stably and reliably adhere thick lead wires onto a smooth electrode surface.

Furthermore, since the pitch between the vibrating elements is very small, it is necessary to use thin wires with low mechanical strength as lead wires, which makes wire breakage more likely to occur.

On the other hand, when using a flexible PC board, the flexible P
It is possible to selectively employ an indirect connection method in which the C board and the electrode are soldered with a lead wire, and a direct connection method in which the flexible PC board and the electrode are soldered without an intervening material.

However, the former method requires a complicated and large amount of processing effort, as the lead wires must be manually soldered to each vibrating element one by one in extremely minute parts.

In addition, in the latter method, even if the pattern accuracy of the flexible PC board is sufficiently increased in advance to match the transducer pitch, the base material will be deformed due to thermal expansion during soldering, and the pattern pitch of the flexible PC board will be and the cutting pitch of the transducer, which results in a situation where it is almost impossible to manufacture, especially in the case of high-density transducers cut into ultra-fine pieces with the intention of improving the image quality of ultrasound diagnostic equipment. .

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve the pattern pitch of the flexible PC board and the cutting pitch of the vibrator even in the case of a vibrator consisting of a large number of high-density elements. It is an object of the present invention to provide a method for manufacturing an ultrasonic transducer, which allows the electrode leads to be accurately matched and to derive electrode leads with extremely stable mechanical strength through simple processing operations.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for manufacturing an ultrasonic vibrator comprising a plurality of vibrating elements in which a piezoelectric material is finely divided. A pattern forming step in which a pattern dividing portion corresponding to the pitch of the vibrating elements is formed on one end side of a flexible PC board formed by concretion on one side by an etching process, and the other end side is left undivided as a common part of the pattern. , a step of connecting the pattern common portion side of the flexible PC board on which the pattern formation process has been completed to the electrode stuck on the surface of the piezoelectric material;
Cutting and dividing a part of the piezoelectric material and the conductive foil material on the common part side at a predetermined pitch to form a plurality of vibrating elements;
The present invention is characterized in that it includes a step of cutting the remaining undivided region of the pattern common portion to independently connect each vibrating element and the pattern division portion.

[Operation] According to the method of the present invention configured as described above, a pattern with a pitch corresponding to the pitch between the vibrating elements is formed on one end of the electrode of the undivided piezoelectric material, and the other end is in the undivided state. Flexible P with the pattern joint part left in
C board is connected.

At this time, the electrodes of the vibrator are soldered so that the common pattern portion side of the flexible PC board faces them.

From this state, the piezoelectric material is cut and divided into a plurality of vibrating elements, and at this time, cuts are also made in a part of the common pattern part of the flexible PC board.

At this stage, the L side of the vibrator has been divided by cutting the piezoelectric material, and the lower side of the flexible PC board has been divided by pattern formation by the etching process or the like. It is understood that the flexible PC board interposed between the pattern dividing portion and the divided vibrating elements is partially left undivided.

As a result of the above, the flexible PC board and the electrode are completely fixedly connected as a whole, and the cutting and division of the piezoelectric material has also been completed, so there will be no inconveniences such as thermal expansion or pitch deviation due to subsequent processing. .

In this way, when the connection process is completed, the common part of the pattern remaining in the undivided state of the flexible PC board is cut using a specified cutter, etc., thereby insulating the adjacent vibrating elements from each other, and separating them from each other. independent electrode leads can be taken out.

[Example] Hereinafter, a preferred example of the present invention will be described based on the drawings.

The characteristic feature of the method of the present invention is that the connection between the electrode and the lead is the most important point in the lead extraction work for the electrode on the piezoelectric material. This is performed on the piezoelectric material in a block state before division, and after stably fixing the relative position of the piezoelectric material and the lead, the lead is made independent for each vibrating element.

As a result, the electrode leads for the finely divided vibrating elements can be taken out by simply cutting a part of the conductive foil material on the flexible PC board, which has already been stably fixed. There are no inconveniences such as misalignment caused by thermal expansion when connecting wires to each element one by one or bonding the vibrating element to a flexible PC board on which a completed pattern has been formed in advance, and it is extremely easy to use. It is possible to easily achieve insulation between the vibrating elements III.

FIG. 1 shows a flexible PC board 10 according to the present invention, on one side of which a conductive foil material 12 such as copper is adhered. One end side of the conductive foil material 12 is subjected to an etching process corresponding to the division pitch of the piezoelectric material into vibrating element units, which will be described later, and a flexible PC board from which the conductive foil material 12 has been removed by this etching process. It can be understood that the portion 10 becomes the insulating region 10a. and,
As is clear from the figure, the other end connected to the piezoelectric electrode is left undivided as a common pattern portion 10c.

The flexible PC that has completed the pattern formation process in this way
The plate 10 is then provided with electrodes 14 on its upper and lower surfaces as shown in FIG.
will be connected to the undivided block-shaped piezoelectric material 16 that has been pasted in advance. The piezoelectric material 16 is placed on a back load 18 for sound absorption, and the pattern-forming surface of the flexible PC board is passed from one end of the plate-side electrode 14 of the piezoelectric material 16 to the side surface of the back load 18. It takes a form.

The connection of the flexible PC board 10 to the electrode 10c of the flexible PC board 10 is performed by soldering, etc., as in the prior art, but at this stage, as is clear from the figure, the piezoelectric material 16 is still connected to the plurality of vibrating elements. The pattern common part 10c of the flexible PC board 10 is not divided into
The pattern is also left in a continuous state without a completed pattern matching the pitch of the vibrating elements.

In the conventional method using a flexible PC board, a piezoelectric material that has already been divided into vibrating elements is connected to a flexible PC board on which a completed pattern matching the pitch of the vibrating elements is formed. For this reason, when soldering, if a severe pitch deviation occurs due to thermal expansion of the material of the flexible PC board, this may remain permanently and it is necessary to take measures such as adjusting it in the subsequent processing process. I can't do it at all.

In contrast, in the method of the present invention, the piezoelectric material 16 to be connected
Since the pattern common portions 10c of the flexible PC board 10 are still in a continuous block state, it is extremely easy to connect them accurately, and even if some deviation occurs due to thermal expansion, it will not be difficult to connect them in the subsequent cutting process. Can be easily adjusted.

From the above, the interconnection of the constituent elements has been completed, and the next step is to cut and divide the piezoelectric material 16 into a predetermined number of multivibration elements.

FIG. 3 shows the state of the piezoelectric material 16 that has been cut and divided into a vibrator array consisting of several stages of elements, and the piezoelectric material 16, which was a block-shaped unit in FIG. When cutting the piezoelectric material 16, the cut extends to a part of the pattern common portion 10c of the flexible PC board 10 connected to the electrode 14 bonded to the bottom surface of the piezoelectric material 16. It is understood that the extent of

This dividing operation is performed using a predetermined cutting machine or the like, and the pitch is determined by etching the pattern dividing portion 10b of the flexible PC board 10 to remove the conductive foil material on the surface and forming pitches in the form of mutually insulated strips. match.

Then, by making the cut into a part of the common portion 10c of the flexible PC board 10, it is possible to check whether the pitch of the etched pattern dividing portion 10b matches the pitch of the divided piezoelectric element 16a, and to check the deviation thereof. It becomes possible to clearly understand the extent to which this is occurring.

Thereafter, as shown by the arrow in FIG. 3, the piezoelectric material 16
Since the tip of the cutting cut and the tip of the insulating portion of the pattern dividing portion 10b formed by the etching process are still left in a common state, by cutting this portion, the transducer elements 16a are separated from the conductive state and are insulated. That will happen.

It is preferable to use an ultrasonic cutter or the like to perform the canting operation of the common pattern portion 10c, which allows extremely fine cutting to be performed accurately.

Figure 4 shows the state of the vibrator after completing all the steps above.
Electrode leads are individually led out from each element 16a of the transducer array, and the conductive foil material 12 of the flexible PC board 10-1- corresponds to each cord 16a that is insulated from each other by the cutting operation. serves as a terminal for connection to an external element, and this conductive foil material 12
A driving pulse for excitation of the vibration element 16a is supplied through the vibration element 16a.

As described above, the method of the present invention performs the most important points in the lead extraction work from the vibrating element, such as connecting the lead material to the electrode on the piezoelectric material and cutting and dividing the piezoelectric material, as a preliminary step in the machining process with a large tolerance. By using a method of insulating each vibrating element and deriving independent leads after the positions of the components of the vibrator as a whole have been determined, it is possible to derive leads from individual vibrating elements, which was the most difficult method with conventional methods. This work essentially only involves cutting the common pattern portion of the flexible PC board at the final stage.

As a result, inconvenient and inefficient work such as considering misalignment due to thermal expansion when connecting flexible PC boards and connecting wires to each vibrating element is completely unnecessary, resulting in a revolutionary simplification of the work process. It is possible to realize the present invention, prevent short-circuits between adjacent elements due to pitch deviation, etc., and extremely easily provide a high-density multi-element type ultrasonic transducer.

[Effects of the Invention] Hereinafter, l: As explained, according to the method of the present invention, after the undivided piezoelectric material and the flexible PC board are connected to stabilize the relative positions of the components, vibration is caused in the final step. Since the elements are cut to insulate each other, it is possible to improve the efficiency of the electrode lead lead-out operation and to stabilize and increase the precision of the vibrator control.

[Brief explanation of the drawings] Figure 1 shows a flexible p
Fig. 2 is a perspective view showing the state in which the flexible PC board is connected to the electrodes; Fig. 3 is a perspective view showing the state in which the piezoelectric material is cut and divided into a plurality of vibrating elements; FIG. 4 is a diagram showing the work of leading out electrode leads from each vibrating element of the ultrasonic vibrator according to the method of the present invention. 10... Flexible PC board 12... Conductive foil material 14... Electrode 16... Piezoelectric material 18... Back load.

Claims (1)

[Claims] (1) In a method for manufacturing an ultrasonic transducer consisting of a plurality of vibrating elements in which a piezoelectric material is finely divided, the vibration A pattern forming step in which a pattern dividing portion corresponding to the pitch of the elements is formed by etching, and the other end side is left in an undivided state as a pattern common portion, and a pattern common portion side of the flexible PC board after the pattern forming process is completed. a step of connecting the piezoelectric material to an electrode stuck on the surface of the piezoelectric material, and a step of cutting and dividing a part of the piezoelectric material and the conductive foil material on the common part side of the pattern at a predetermined pitch to form a plurality of vibration elements. A method for manufacturing an ultrasonic transducer, comprising the steps of: cutting the remaining undivided region of the pattern common portion to individually and independently connect each vibrating element and the pattern dividing portion. .