JPH0614397A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To provide the ultrasonic probe for maintaining satisfactorily the quality, and also, enhancing the productivity. CONSTITUTION:The ultrasonic probe is so constituted one end side on which a conductive line 5 of a flexible printed board 4 is exposed is joined to one principal surface on one side of a piezoelectric plate 1 having an electrode on both principal faces, one principal surface of the piezoelectric plate 1 is fixed on a packing material 3, and thereafter, a gap 6 for reaching the packing material 3 from the other principal surface side of the piezoelectric plate 1 is provided, divided into plural minute piezoelectric pieces, and also, the electrode 2 is derived. This ultrasonic probe is constituted by interposing an anisotropic conductive material 9 having conductivity and an insulation property in the thickness direction and the principal face direction, respectively between one principal face of one side of the piezoelectric plate and one end side of the flexible printed board 4, joining the piezoelectric plate 1, the flexible printed board 4 and the anisotropic conductive material 9 by thermal pressure, and thereafter, the piezoelectric plate 1 is fixed to the packing material 3 and divided into minute piezoelectric pieces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an application field of an array type ultrasonic probe (hereinafter referred to as an array type probe), and in particular, an array type probe having good electrode derivation work and maintaining quality. Regarding

[0002]

BACKGROUND OF THE INVENTION An ultrasonic probe is useful as an ultrasonic wave transmitter / receiver in ultrasonic diagnostic equipment (medical) and flaw detector (mining and industrial), and one of these is an arrayed probe. The array type probe has a plurality of rectangular piezoelectric pieces arranged in a row,
For example, it is driven by electronic scanning such as linear or sector method. In recent years, there has been a demand for an ultrasonic probe having a structure with excellent workability due to an increase in demand.

[0003]

2. Description of the Related Art FIG. 3 is a diagram of an ultrasonic probe for explaining a conventional example of this type. In the array type probe, each of the plurality of minute piezoelectric pieces 1 serving as an ultrasonic wave generation source is, for example, lead zirconate titanate (commonly called PZT). Micro piezoelectric piece 1
Are formed with electrodes 2 (ab) for driving them on both main surfaces thereof. Then, a plurality of them are arranged on the backing material 3 in the width direction. One end of a flexible printed board (hereinafter referred to as a flexible board) 4 is interposed between the minute piezoelectric piece 1 and the backing material 3, and the electrode 2 is led out by its conductive path 5. Generally, a common electric path portion provided at one end of the flexible substrate 4 is joined and integrated with one main surface of one side of a rectangular piezoelectric plate, and then these are fixed onto the backing material 3. (Not shown). Usually, a common electric circuit portion of a flexible substrate is plated with solder and connected to a piezoelectric plate by a weld (thermocompression) device. Then, the slit 6 reaching the backing material 3 from the piezoelectric plate is made to divide the piezoelectric plate into a plurality of minute piezoelectric pieces 1, and the electrodes are led out from each minute piezoelectric piece 1. An acoustic matching layer (not shown) is formed on the front surface of the piezoelectric plate as needed.

[0004]

However, in such an ultrasonic probe, it is difficult to accurately control the thickness (amount) of the solder plating 7 applied to the common electric path portion of the flexible substrate 4, and this is the cause. Then there was the next problem. That is, as shown in the cross-sectional view of FIG. 4, when the solder plating 7 is thick, the excess (excess solder) 7a flows out in a ball shape to the flexible substrate side at the time of welding.
Then, due to the hardness of the excess solder 7a, the flexible substrate 4
Of the conductive path 5 is broken, and the conductive path 5 is broken in the “(a) direction in the drawing” at the time of bending, for example. Alternatively, excess solder 7a
There are many accidents where the battery is released and short-circuited with the adjacent electrodes. On the contrary, when the solder plating 7 is thin, the connection strength with the piezoelectric plate 1 becomes small, and there is a problem that peeling frequently occurs due to stress (external force) during processing in a subsequent process or the like.
For this reason, not only the quality but also the productivity is deteriorated due to the deterioration of the yield.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic probe which maintains good quality and has improved productivity.

[0006]

According to the present invention, between a main surface on one side of a piezoelectric plate and one end side of the flexible printed circuit board, there is a difference having conductivity in the thickness direction and insulation in the main surface direction. Solved that the piezoelectric plate, the flexible printed circuit board, and the anisotropic conductive material were bonded by thermocompression bonding with the directional conductive material interposed therebetween, and then the piezoelectric plate was fixed to a backing material and divided into minute piezoelectric pieces. Use it as a means. An embodiment of the present invention will be described below.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram of an ultrasonic probe for explaining one embodiment of the present invention. The same parts as those in the previous embodiment are designated by the same reference numerals, and the description thereof will be simplified. Array type transducer
As described above, generally, on one main surface of one side of the piezoelectric plate 1,
After the flexible substrate 4 is integrated and fixed to the backing material 3, the flexible board 4 is divided into a plurality of minute piezoelectric pieces 1 with a cut 6 reaching the backing material 3 and electrodes are led out from each minute piezoelectric piece 1 (previous third). See figure). Then, in this embodiment, the anisotropic conductive material 9 is interposed between the one main surface on one side of the piezoelectric plate 1 and the common electric path portion 8 provided on one end side of the flexible substrate 4. That is, the flexible substrate 4, the piezoelectric plate 1, and the anisotropic conductive material 9 are joined by thermocompression to be integrated. The anisotropic conductive material 9 has a film (sheet) shape, has conductivity in the thickness direction, and is in the main surface direction (width direction).
Has insulating properties. For example, the product name "Anisolm" manufactured by Hitachi Chemical is used. Then, it is divided into a plurality of minute piezoelectric pieces 1 and each electrode 2b of each minute piezoelectric piece 1 is led out by the conductive path 5 of the flexible substrate 4 through the anisotropic conductive material 9. The electrode 2a on the other main surface side is connected by, for example, a lead wire or a common electrode, and is connected to the reference potential path of the flexible substrate 4 (not shown). Further, an acoustic matching layer or the like is provided on the other main surface side as necessary.

With such a construction, the thickness of the anisotropically conductive material 9 and the pressure and temperature of the weld device are appropriately set to maintain the connection strength, and the excess flexibility. The outflow to the substrate 4 is prevented. That is, since the anisotropic conductive material 9 has low fluidity when melted by thermocompression bonding, it is possible to prevent the excess outflow. Therefore, the anisotropic conductive material 9 also has flexibility and prevents breakage of the conductive path 5 when the flexible substrate 4 is bent. And since there is no excess outflow, an electrical short circuit due to these is prevented. In addition, since the anisotropic conductive material 9 has an insulating property in the width direction, it prevents electrical coupling between adjacent ones and enhances the independence of the minute piezoelectric piece 1. further,
Since the solder plating application work described above is unnecessary, the joining work is facilitated. Therefore, the yield is improved and the productivity is improved together with the quality.

[0009]

[Other Matters] In the above embodiment, the anisotropic conductive material 9 is thermocompression bonded. However, in this case, thermocompression bonding may be performed using ultrasonic waves or a laser. Anything can be used as long as it can be joined. As described above, the present invention can be freely applied within the scope of the invention.

[0010]

According to the present invention, between the one principal surface on one side of the piezoelectric plate and the one end side of the flexible printed board, there is conductivity in the thickness direction and insulation in the principal surface direction. After interposing an anisotropic conductive material, the piezoelectric plate, the flexible printed board and the anisotropic conductive material are bonded by thermocompression bonding,
Since the piezoelectric plate is fixed to a backing material and divided into minute piezoelectric pieces, it is possible to provide an ultrasonic probe which maintains good quality and improves productivity.

[Brief description of drawings]

FIG. 1 is a diagram of an array type probe excluding a backing material before cutting for explaining an embodiment of the present invention.

FIG. 2 (a) is a front view of an array type probe for explaining an embodiment of the present invention, and FIG. 2 (b) is a side sectional view thereof.

FIG. 3 is a front view of an array type probe for explaining a conventional example.

FIG. 4 is a cross-sectional view of an array type probe for explaining a conventional example.

[Explanation of symbols]

1 Micro Piezoelectric Piece (or Piezoelectric Plate), 2 Electrodes, 3 Backing Material, 4 Flexible Substrate, 5 Conductive Path, 6 Cut, 7 Solder, 7b Excessive Solder, 8 Common Electric Path, 9
Anisotropic conductive material.

Claims (1)

[Claims] 1. A piezoelectric printed board having electrodes on both main surfaces is joined to one main surface on one side of the piezoelectric printed board, the one end side where a conductive path of a flexible printed circuit board is exposed, and the one main surface of the piezoelectric board is placed on a backing material. After being fixed to the piezoelectric plate, a cut reaching the backing material from the other main surface side of the piezoelectric plate is provided, and the ultrasonic probe is divided into a plurality of minute piezoelectric pieces and the electrodes are led out. An anisotropic conductive material having conductivity in the thickness direction and insulation in the direction of the main surface is interposed between one main surface and one end side of the flexible printed board, and the piezoelectric plate and the flexible printed board are provided. An ultrasonic probe in which a substrate and an anisotropic conductive material are bonded by thermocompression bonding and then the piezoelectric plate is fixed to a backing material and divided into minute piezoelectric pieces.